Endangered and Threatened Wildlife and Plants; Threatened Species Status With a Section 4(d) Rule for Bracted Twistflower and Designation of Critical Habitat
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DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 17 [Docket No. FWS-R2-ES-2021-0013; FF09E21000 FXES1111090FEDR 223] RIN 1018-BE44 Endangered and Threatened Wildlife and Plants; Threatened Species Status With a Section 4(d) Rule for Bracted Twistflower and Designation of Critical Habitat AGENCY:
Fish and Wildlife Service, Interior.
ACTION:
Proposed rule.
SUMMARY:
We, the U.S. Fish and Wildlife Service (Service), announce a 12-month finding on a petition to list the bracted twistflower ( Streptanthus bracteatus ), a plant species from Texas, as a threatened species and designate critical habitat under the Endangered Species Act of 1973, as amended (Act). After a review of the best available scientific and commercial information, we find that listing the species is warranted. Accordingly, we propose to list bracted twistflower as a threatened species with a rule issued under section 4(d) of the Act (a “4(d) rule”). We also propose to designate critical habitat for the bracted twistflower under the Act. In total, approximately 1,606 acres (650 hectares) in Uvalde, Medina, Bexar, and Travis Counties in Texas fall within the boundaries of the proposed critical habitat designation. In addition, we announce the availability of a draft economic analysis (DEA) of the proposed designation of critical habitat for the bracted twistflower. If we finalize this rule as proposed, it would extend the Act's protections to this species and its critical habitat.
DATES:
We will accept comments received or postmarked on or before January 10, 2022. Comments submitted electronically using the Federal eRulemaking Portal (see ADDRESSES , below) must be received by 11:59 p.m. Eastern Time on the closing date. We must receive requests for a public hearing, in writing, at the address shown in FOR FURTHER INFORMATION CONTACT by December 27, 2021.
ADDRESSES:
Written comments: You may submit comments by one of the following methods:
0, 2022. Comments submitted electronically using the Federal eRulemaking Portal (see ADDRESSES , below) must be received by 11:59 p.m. Eastern Time on the closing date. We must receive requests for a public hearing, in writing, at the address shown in FOR FURTHER INFORMATION CONTACT by December 27, 2021.
ADDRESSES:
Written comments: You may submit comments by one of the following methods:
(1) Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov. In the Search box, enter the docket number or RIN for this rulemaking (presented above in the document headings). For best results, do not copy and paste either number; instead, type the docket number or RIN into the Search box using hyphens. Then, click on the Search button. On the resulting page, in the Search panel on the left side of the screen, under the Document Type heading, check the Proposed Rule box to locate this document. You may submit a comment by clicking on “Comment.”
(2) By hard copy: Submit by U.S. mail to: Public Comments Processing, Attn: FWS-R2-ES-2021-0013, U.S. Fish and Wildlife Service, MS: PRB/3W, 5275 Leesburg Pike, Falls Church, VA 22041-3803.
We request that you send comments only by the methods described above. We will post all comments on http://www.regulations.gov. This generally means that we will post any personal information you provide us (see Information Requested, below, for more information).
Availability of supporting materials: For the critical habitat designation, the coordinates or plot points or both from which the maps are generated are included in the decision file and are available at http://www.regulations.gov under Docket No. FWS-R2-ES-2021-0013, and at the Austin Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT )
equested, below, for more information).
Availability of supporting materials: For the critical habitat designation, the coordinates or plot points or both from which the maps are generated are included in the decision file and are available at http://www.regulations.gov under Docket No. FWS-R2-ES-2021-0013, and at the Austin Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT ). Any additional tools or supporting information that we may develop for the critical habitat designation will also be available at the Service website and Field Office set out above, and may also be included in the preamble and/or at http://www.regulations.gov.
FOR FURTHER INFORMATION CONTACT:
Adam Zerrenner, Field Supervisor, U.S. Fish and Wildlife Service, Austin Ecological Services Field Office, 10711 Burnet Road, Suite 200, Austin, TX 78758; telephone 512-490-0057. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Relay Service at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Executive Summary
Why we need to publish a rule. Under the Act, if we determine that a species is an endangered or threatened species throughout all or a significant portion of its range, we are required to promptly publish a proposal in the Federal Register and make a determination on our proposal within 1 year. To the maximum extent prudent and determinable, we must designate critical habitat for any species that we determine to be an endangered or threatened species under the Act. Listing a species as an endangered or threatened species and designation of critical habitat can only be completed by issuing a rule.
What this document does. We propose to list the bracted twistflower as a threatened species with a species-specific 4(d) rule under the Act. We also propose to designate critical habitat for the species.
The basis for our action
threatened species under the Act. Listing a species as an endangered or threatened species and designation of critical habitat can only be completed by issuing a rule.
What this document does. We propose to list the bracted twistflower as a threatened species with a species-specific 4(d) rule under the Act. We also propose to designate critical habitat for the species.
The basis for our action. Under section 4(a) of the Act, we may determine that a species is an endangered or threatened species because of any of the following five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; or (E) other natural or manmade factors affecting its continued existence. We have determined that the primary threats to the bracted twistflower are loss of habitat due to urban and residential development, changes in structure and composition of vegetation and wildfire frequency, and herbivory by dense populations of white-tailed deer ( Odocoileus virginianus ) and introduced ungulates.
Section 4(a)(3) of the Act requires the Secretary of the Interior (Secretary) to designate critical habitat concurrent with listing to the maximum extent prudent and determinable. Section 3(5)(A) of the Act defines critical habitat as (i) the specific areas within the geographical area occupied by the species, at the time it is listed, on which are found those physical or biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protections; and (ii) specific areas outside the geographical area occupied by the species at the time it is listed, upon a determination by the Secretary that such areas are essential for the conservation of the species
s listed, on which are found those physical or biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protections; and (ii) specific areas outside the geographical area occupied by the species at the time it is listed, upon a determination by the Secretary that such areas are essential for the conservation of the species. Section 4(b)(2) of the Act states that the Secretary must make the designation on the basis of the best scientific data available and after taking into consideration the economic impact, the impact on national security, and any other relevant impacts of specifying any particular area as critical habitat.
Information Requested
We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from other concerned governmental agencies, Native
We particularly seek comments concerning:
(1) The species' biology, range, and population trends, including:
(a) Biological or ecological requirements of the species, including habitat requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range, including distribution patterns;
(d) Historical and current population levels, and current and projected trends; and
ents concerning:
(1) The species' biology, range, and population trends, including:
(a) Biological or ecological requirements of the species, including habitat requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range, including distribution patterns;
(d) Historical and current population levels, and current and projected trends; and
(e) Past and ongoing conservation measures for the species, its habitat, or both.
(2) Factors that may affect the continued existence of the species, which may include habitat modification or destruction, overutilization, disease, predation, the inadequacy of existing regulatory mechanisms, or other natural or manmade factors.
(3) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to this species and existing regulations that may be addressing those threats.
(4) Additional information concerning the historical and current status, range, distribution, and population size of this species, including the locations of any additional populations of this species.
(5) Information on regulations that are necessary and advisable to provide for the conservation of the bracted twistflower and that the Service can consider in developing a 4(d) rule for the species. In particular, information concerning the extent to which we should include any of the section 9 prohibitions in the 4(d) rule or whether we should consider any additional exceptions from the prohibitions in the 4(d) rule.
(6) The reasons why we should or should not designate habitat as “critical habitat” under section 4 of the Act (16 U.S.C. 1531 et seq. ), including information to inform the following factors that the regulations identify as reasons why designation of critical habitat may be not prudent:
(a) The species is threatened by taking or other human activity and identification of critical habitat can be expected to increase the degree of such threat to the species;
“critical habitat” under section 4 of the Act (16 U.S.C. 1531 et seq. ), including information to inform the following factors that the regulations identify as reasons why designation of critical habitat may be not prudent:
(a) The species is threatened by taking or other human activity and identification of critical habitat can be expected to increase the degree of such threat to the species;
(b) The present or threatened destruction, modification, or curtailment of a species' habitat or range is not a threat to the species, or threats to the species' habitat stem solely from causes that cannot be addressed through management actions resulting from consultations under section 7(a)(2) of the Act;
(c) Areas within the jurisdiction of the United States provide no more than negligible conservation value, if any, for a species occurring primarily outside the jurisdiction of the United States; or
(d) No areas meet the definition of critical habitat.
(7) Specific information on:
(a) The amount and distribution of bracted twistflower habitat;
(b) What areas, that were occupied at the time of listing and that contain the physical or biological features essential to the conservation of the species, should be included in the designation and why;
(c) Any additional areas occurring within the range of the species [ i.e., Travis, Medina, Uvalde, Bexar, Hays Counties] that should be included in the designation because they (1) are occupied at the time of listing and contain the physical or biological features that are essential to the conservation of the species and that may require special management considerations, or (2) are unoccupied at the time of listing and are essential for the conservation of the species;
(d) Special management considerations or protection that may be needed in critical habitat areas we are proposing, including managing for the potential effects of climate change; and
ures that are essential to the conservation of the species and that may require special management considerations, or (2) are unoccupied at the time of listing and are essential for the conservation of the species;
(d) Special management considerations or protection that may be needed in critical habitat areas we are proposing, including managing for the potential effects of climate change; and
(e) What areas not occupied at the time of listing are essential for the conservation of the species. We particularly seek comments:
(i) Regarding whether occupied areas are adequate for the conservation of the species;
(ii) Providing specific information regarding whether or not unoccupied areas would, with reasonable certainty, contribute to the conservation of the species and contain at least one physical or biological feature essential to the conservation of the species.
(iii) Explaining whether or not unoccupied areas fall within the definition of “habitat” at 50 CFR 424.02 and why.
(8) Land use designations and current or planned activities in the subject areas and their possible impacts on proposed critical habitat.
(9) Any probable economic, national security, or other relevant impacts of designating any area that may be included in the final designation, and the related benefits of including or excluding specific areas.
(10) Information on the extent to which the description of probable economic impacts in the draft economic analysis is a reasonable estimate of the likely economic impacts.
(11) Whether any specific areas we are proposing for critical habitat designation should be considered for exclusion under section 4(b)(2) of the Act, and whether the benefits of potentially excluding any specific area outweigh the benefits of including that area under section 4(b)(2) of the Act. If you think we should exclude any additional areas, please provide credible information regarding the existence of a meaningful economic or other relevant impact supporting a benefit of exclusion.
idered for exclusion under section 4(b)(2) of the Act, and whether the benefits of potentially excluding any specific area outweigh the benefits of including that area under section 4(b)(2) of the Act. If you think we should exclude any additional areas, please provide credible information regarding the existence of a meaningful economic or other relevant impact supporting a benefit of exclusion.
(12) Whether we could improve or modify our approach to designating critical habitat in any way to provide for greater public participation and understanding, or to better accommodate public concerns and comments.
Please include sufficient information with your submission (such as scientific journal articles or other publications) to allow us to verify any scientific or commercial information you include.
Please note that submissions merely stating support for, or opposition to, the action under consideration without providing supporting information, although noted, will not be considered in making a determination, as section 4(b)(1)(A) of the Act directs that determinations as to whether any species is an endangered or a threatened species must be made “solely on the basis of the best scientific and commercial data available.”
You may submit your comments and materials concerning this proposed rule by one of the methods listed in ADDRESSES . We request that you send comments only by the methods described in ADDRESSES .
If you submit information via http://www.regulations.gov, your entire submission—including any personal identifying information—will be posted on the website. If your submission is made via a hardcopy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy submissions on http://www.regulations.gov
ission—including any personal identifying information—will be posted on the website. If your submission is made via a hardcopy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy submissions on http://www.regulations.gov.
Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on http://www.regulations.gov.
Because we will consider all comments and information we receive during the comment period, our final determinations may differ from this proposal. Based on the new information
Public Hearing
Section 4(b)(5) of the Act provides for a public hearing on this proposal, if requested. Requests must be received by the date specified in DATES . Such requests must be sent to the address shown in FOR FURTHER INFORMATION CONTACT . We will schedule a public hearing on this proposal, if requested, and announce the date, time, and place of the hearing, as well as how to obtain reasonable accommodations, in the Federal Register and local newspapers at least 15 days before the hearing. For the immediate future, we will provide these public hearings using webinars that will be announced on the Service's website, in addition to the Federal Register . The use of these virtual public hearings is consistent with our regulations at 50 CFR 424.16(c)(3).
Previous Federal Actions
In 1975, the Smithsonian Institution presented a report to Congress describing over 3,000 vascular plants considered endangered, threatened, or extinct in the United States, including the bracted twistflower
on the Service's website, in addition to the Federal Register . The use of these virtual public hearings is consistent with our regulations at 50 CFR 424.16(c)(3).
Previous Federal Actions
In 1975, the Smithsonian Institution presented a report to Congress describing over 3,000 vascular plants considered endangered, threatened, or extinct in the United States, including the bracted twistflower. The Service published a notice on July 1, 1975 (40 FR 27824), in which we announced that this report had been accepted as a petition under the terms of the Act, and that the taxa named in the report and notice were being reviewed for possible inclusion in the List of Endangered and Threatened Plants.
On December 15, 1980, we classified the bracted twistflower as a Category 2 candidate for listing (45 FR 82480). We defined Category 2 candidates as taxa for which information in the Service's possession indicated the probable appropriateness of listing as endangered or threatened, but for which sufficient information was not available to biologically support a proposed rule at the time. The species remained so designated in subsequent candidate notices of review (CNORs) (50 FR 39526, September 27, 1985; 55 FR 6184, February 21, 1990; 58 FR 51144, September 30, 1993). In the February 28, 1996, CNOR (61 FR 7596), we discontinued the designation of Category 2 species as candidates; therefore, the bracted twistflower was no longer a candidate species.
On October 26, 2011, we added bracted twistflower to the candidate list (76 FR 66370). Candidates are those fish, wildlife, and plants for which we have on file sufficient information on biological vulnerability and threats to support preparation of a listing proposal, but for which preparation and publication of a proposal is precluded by higher priority listing actions
ger a candidate species.
On October 26, 2011, we added bracted twistflower to the candidate list (76 FR 66370). Candidates are those fish, wildlife, and plants for which we have on file sufficient information on biological vulnerability and threats to support preparation of a listing proposal, but for which preparation and publication of a proposal is precluded by higher priority listing actions. Bracted twistflower was included in all subsequent annual CNORs with a listing priority number of 8, which reflects a species with threats that are ongoing and imminent (77 FR 69994, November 21, 2012; 78 FR 70104, November 22, 2013; 79 FR 72450, December 5, 2014; 80 FR 80584, December 24, 2015; 81 FR 87246, December 2, 2016; 84 FR 54732, October 10, 2019; 85 FR 73164, November 16, 2020).
On August 5, 2014, we received a petition to list the bracted twistflower. Because the species was already on our candidate list, we took no additional action on the petition.
Supporting Documents
A species status assessment (SSA) team prepared an SSA report for the bracted twistflower. The SSA team was composed of Service biologists in consultation with other species experts. The SSA report represents a compilation of the best scientific and commercial data available concerning the status of the species, including the impacts of past, present, and future factors (both negative and beneficial) affecting the species. In accordance with our joint policy on peer review published in the Federal Register on July 1, 1994 (59 FR 34270), and our August 20, 2016, memorandum updating and clarifying the role of peer review of listing actions under the Act, we sought the expert opinions of six appropriate specialists regarding the SSA. We received one response. We also sent the SSA report to four partners, including scientists with expertise in local plant species, for review. We received review from four partners (Texas Parks and Wildlife Department, the City of Austin, the City of San Antonio, and Joint Base San Antonio).
I
actions under the Act, we sought the expert opinions of six appropriate specialists regarding the SSA. We received one response. We also sent the SSA report to four partners, including scientists with expertise in local plant species, for review. We received review from four partners (Texas Parks and Wildlife Department, the City of Austin, the City of San Antonio, and Joint Base San Antonio).
I. Proposed Listing Determination
Background
Bracted twistflower is an annual herbaceous plant in the mustard family (Brassicaceae) that occurs only along the southeastern edge of the Edwards Plateau of central Texas. There are currently 35 described species of Streptanthus. Bracted twistflower can be distinguished from most other members of this genus because the leaves borne on the flower stalk lack stems and all flower stems have a small modified leaf, called a bract, at their bases.
Bracted twistflower habitats occur near the boundary between the Edwards or Devils River limestone formations and the Glen Rose limestone formation. Individual plants commonly occur near or under a canopy of Ashe juniper ( Juniperus ashei ), Texas live oak ( Quercus fusiformis ), Texas mountain laurel ( Sophora secundiflora ), Texas red oak ( Quercus buckleyi ), or other trees.
The seeds germinate in response to fall and winter rainfall, forming basal rosettes, and the flower stalks emerge the following spring bearing showy, lavender-purple flowers. The seed capsules remain attached to the stalks during the summer as they mature and dehisce, releasing the seeds to be dispersed by gravity. The foliage withers as the fruits mature, and the plants die during the heat of summer. This species is primarily an outcrossing species; the leafcutter bee Megachile comata (family: Megachilidae) is known to be an effective pollinator. Because the seeds of bracted twistflower do not disperse far, gene flow for this species occurs mainly through pollination
ng the seeds to be dispersed by gravity. The foliage withers as the fruits mature, and the plants die during the heat of summer. This species is primarily an outcrossing species; the leafcutter bee Megachile comata (family: Megachilidae) is known to be an effective pollinator. Because the seeds of bracted twistflower do not disperse far, gene flow for this species occurs mainly through pollination.
Since 1989, populations of the bracted twistflower have been documented at 17 naturally occurring element occurrences (EOs) in five counties, as well as one experimental trial in Travis County (see Table 1, below). We have adopted the EO standard to maintain consistency with the Texas Parks and Wildlife Department's Natural Diversity Database (TXNDD) and because the EOs used in the TXNDD are practical approximations of populations, based on the best available scientific information. Each EO may consist of one to many Source Features, which are specific locations where one or more
Bracted twistflower is an annual plant, and the numbers of individuals that germinate at the Source Features of each EO vary widely from year to year in response to weather patterns or other stimuli. Thus, the numbers observed in any single year are not useful measures of population size because they do not reveal the numbers of live, dormant seeds that persist in the soil seed reserve. The SSA report (Service 2021, appendix A) describes the method we used to estimate the potential population sizes of EOs, which we define as the largest numbers of individuals that have been observed at each Source Feature of each EO. We then used aerial imagery to determine whether the habitat of any Source Features had been destroyed by construction of roads, buildings, or other disturbance, and we calculated the estimated remaining potential population at each EO. For a complete descriptions of the analysis used, see the SSA report
the largest numbers of individuals that have been observed at each Source Feature of each EO. We then used aerial imagery to determine whether the habitat of any Source Features had been destroyed by construction of roads, buildings, or other disturbance, and we calculated the estimated remaining potential population at each EO. For a complete descriptions of the analysis used, see the SSA report. Table 1 lists the total potential populations of each EO and the proportions of each that were reported from Source Features that were destroyed, partially destroyed, or are still intact. In summary, within the naturally-occurring EOs, we determined that habitats and potential populations are completely intact at 11 EOs, partially destroyed at four EOs, and completely destroyed at two EOs. However, even where habitats are intact, populations may decline due to ungulate herbivory, juniper competition, or other factors. A thorough review of the taxonomy, life history, and ecology of the bracted twistflower is presented in the SSA report (Service 2021, entire).
Table 1—Bracted Twistflower Element Occurrences (EOs), Potential Population Sizes (Numbers of Individuals), and Habitat Statuses of Source Features EO—site name; owner; representation area 1 Total potential population of all source features Potential population by habitat status Intact Destroyed Partially destroyed Percent remaining intact 2—Cat Mountain (Far West); Private; NE 866 123 112 631 14.2 7—Ullrich Water Treatment Plant (Bee Creek Preserve); City of Austin; NE 493 493 0 0 100.0 9—Mt. Bonnell/Mt
nd Habitat Statuses of Source Features EO—site name; owner; representation area 1 Total potential population of all source features Potential population by habitat status Intact Destroyed Partially destroyed Percent remaining intact 2—Cat Mountain (Far West); Private; NE 866 123 112 631 14.2 7—Ullrich Water Treatment Plant (Bee Creek Preserve); City of Austin; NE 493 493 0 0 100.0 9—Mt. Bonnell/Mt. Bonnell City Park; Private/City of Austin; NE 919 237 433 249 25.8 17—Barton Creek Wilderness Park; City of Austin (Balcones Canyonlands Preserve (BCP)); NE 1,677 1,677 0 0 100.0 21—Mesa-FM 2222; Private; NE 330 0 70 260 0.0 26—Bright Leaf State Natural Area (SNA); Austin Community Foundation; NE 10 10 0 0 100.0 32—Rough Hollow Ranch; Private; NE 40 0 40 0 0.0 33 2 —Vireo Preserve (experimental reintroduction); City of Austin (BCP); NE 120 35—Valburn Drive/Bull Creek District Park; Private/City of Austin; NE 1,041 343 644 54 32.9 36—Gus Fruh/Barton Creek Greenbelt; City of Austin; NE 29 29 0 0 100.0 xx 3 —Falls Ranch; Private; NE 6 6 0 0 100.0 8—E Medina Lake; Texas Department of Transportation, Medina County, and private rights-of-way; C 2,260 477 481 1,302 21.1 18—Medina Lake; Private; C 1,254 1,254 0 0 100.0 23—Eisenhower City Park/Camp Bullis Military Training Reservation; City of San Antonio/Dept. of Defense; C 190 190 0 0 100.0 25—Laurel Canyon (Bear Bluff); Private Limited Partnership with City of San Antonio conservation easement; C 2,000 2,000 0 0 100.0 31—Rancho Diana (undeveloped natural area); City of San Antonio; C 958 958 0 0 100.0 10—Garner State Park; Texas Parks and Wildlife Department; W 686 686 0 0 100.0 24—Upper Long Canyon; Private; W 5 5 0 0 100.0 1 Described under Species Needs, below. NE = northeast; C = central; W = west. 2 This experimental reintroduction is not one of the 17 naturally-occurring EOs. 3 This newly-discovered site does not yet have in EO ID or EO number in the TXNDD. Regulatory and Analytical Framework
Regulatory Framework
Section 4 of the Act (16 U.S.C
686 686 0 0 100.0 24—Upper Long Canyon; Private; W 5 5 0 0 100.0 1 Described under Species Needs, below. NE = northeast; C = central; W = west. 2 This experimental reintroduction is not one of the 17 naturally-occurring EOs. 3 This newly-discovered site does not yet have in EO ID or EO number in the TXNDD. Regulatory and Analytical Framework
Regulatory Framework
Section 4 of the Act (16 U.S.C. 1533) and its implementing regulations (50 CFR part 424) set forth the procedures for determining whether a species is an endangered species or a threatened species. The Act defines an endangered species as a species that is in danger of extinction throughout all or a significant portion of its range, and a threatened species as a species that is “likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range”. The Act requires that we determine whether any species is an endangered species or a threatened species because of any of the following factors:
(A) The present or threatened destruction, modification, or curtailment of its habitat or range;
(B) Overutilization for commercial, recreational, scientific, or educational purposes;
(C) Disease or predation;
(D) The inadequacy of existing regulatory mechanisms; or
(E) Other natural or manmade factors affecting its continued existence.
These factors represent broad categories of natural or human-caused actions or conditions that could have an effect on a species' continued existence. In evaluating these actions and
We use the term “threat” to refer in general to actions or conditions that are known to or are reasonably likely to negatively affect individuals of a species. The term “threat” includes actions or conditions that have a direct impact on individuals (direct impacts), as well as those that affect individuals through alteration of their habitat or required resources (stressors)
g these actions and
We use the term “threat” to refer in general to actions or conditions that are known to or are reasonably likely to negatively affect individuals of a species. The term “threat” includes actions or conditions that have a direct impact on individuals (direct impacts), as well as those that affect individuals through alteration of their habitat or required resources (stressors). The term “threat” may encompass—either together or separately—the source of the action or condition or the action or condition itself.
However, the mere identification of any threat(s) does not necessarily mean that the species meets the statutory definition of an “endangered species” or a “threatened species.” In determining whether a species meets either definition, we must evaluate all identified threats by considering the expected response by the species, and the effects of the threats—in light of those actions and conditions that will ameliorate the threats—on an individual, population, and species level. We evaluate each threat and its expected effects on the species, then analyze the cumulative effect of all of the threats on the species as a whole. We also consider the cumulative effect of the threats in light of those actions and conditions that will have positive effects on the species—such as any existing regulatory mechanisms or conservation efforts. The Secretary determines whether the species meets the definition of an “endangered species” or a “threatened species” only after conducting this cumulative analysis and describing the expected effect on the species now and in the foreseeable future.
The Act does not define the term “foreseeable future,” which appears in the statutory definition of “threatened species.” Our implementing regulations at 50 CFR 424.11(d) set forth a framework for evaluating the foreseeable future on a case-by-case basis
ed species” only after conducting this cumulative analysis and describing the expected effect on the species now and in the foreseeable future.
The Act does not define the term “foreseeable future,” which appears in the statutory definition of “threatened species.” Our implementing regulations at 50 CFR 424.11(d) set forth a framework for evaluating the foreseeable future on a case-by-case basis. The term “foreseeable future” extends only so far into the future as the Service can reasonably determine that both the future threats and the species' responses to those threats are likely. In other words, the foreseeable future is the period of time in which we can make reliable predictions. “Reliable” does not mean “certain”; it means sufficient to provide a reasonable degree of confidence in the prediction. Thus, a prediction is reliable if it is reasonable to depend on it when making decisions.
It is not always possible or necessary to define foreseeable future as a particular number of years. Analysis of the foreseeable future uses the best scientific and commercial data available and should consider the timeframes applicable to the relevant threats and to the species' likely responses to those threats in view of its life-history characteristics. Data that are typically relevant to assessing the species' biological response include species-specific factors such as lifespan, reproductive rates or productivity, and other demographic factors.
Analytical Framework
The SSA report (Service 2021, entire) documents the results of our comprehensive biological review of the best scientific and commercial data regarding the status of the species, including an assessment of the potential threats to the species. The SSA report does not represent a decision by the Service on whether the species should be proposed for listing as an endangered or threatened species under the Act
port (Service 2021, entire) documents the results of our comprehensive biological review of the best scientific and commercial data regarding the status of the species, including an assessment of the potential threats to the species. The SSA report does not represent a decision by the Service on whether the species should be proposed for listing as an endangered or threatened species under the Act. However, it does provide the scientific basis that informs our regulatory decisions, which involve the further application of standards within the Act and its implementing regulations and policies. The following is a summary of the key results and conclusions from the SSA report; the full SSA report can be found at Docket No. FWS-R2-ES-2021-0013 on http://www.regulations.gov.
To assess bracted twistflower viability, we used the three conservation biology principles of resiliency, redundancy, and representation (Shaffer and Stein 2000, pp. 306-310). Briefly, resiliency supports the ability of the species to withstand environmental and demographic stochasticity (for example, wet or dry, warm or cold years), redundancy supports the ability of the species to withstand catastrophic events (for example, droughts, large pollution events), and representation supports the ability of the species to adapt over time to long-term changes in the environment (for example, climate changes). In general, the more resilient and redundant a species is and the more representation it has, the more likely it is to sustain populations over time, even under changing environmental conditions. Using these principles, we identified the species' ecological requirements for survival and reproduction at the individual, population, and species levels, and described the beneficial and risk factors influencing the species' viability.
The SSA process can be categorized into three sequential stages. During the first stage, we evaluated the individual species' life-history needs
tal conditions. Using these principles, we identified the species' ecological requirements for survival and reproduction at the individual, population, and species levels, and described the beneficial and risk factors influencing the species' viability.
The SSA process can be categorized into three sequential stages. During the first stage, we evaluated the individual species' life-history needs. The next stage involved an assessment of the historical and current condition of the species' demographics and habitat characteristics, including an explanation of how the species arrived at its current condition. The final stage of the SSA involved making predictions about the species' responses to positive and negative environmental and anthropogenic influences. Throughout all of these stages, we used the best available information to characterize viability as the ability of a species to sustain populations in the wild over time. We use this information to inform our regulatory decision.
Summary of Biological Status and Threats
In this discussion, we review the biological condition of the species and its resources, and the factors that influence the species' current and future condition, in order to assess the species' overall viability and the risks to that viability. We analyze these factors both individually and cumulatively to determine the current condition of the species and project the future condition of the species under several plausible future scenarios.
Species Needs
Habitat Availability and Protection From Herbivory
Bracted twistflower habitat occurs on karstic, porous limestones near the boundary of the Devils River or Edwards formations and Glen Rose formations in central Texas. These juniper-oak woodlands and shrublands experience hot, often dry summers and mild winters with bimodal (spring and fall) precipitation patterns. Optimal microsites for the bracted twistflower have less than 50 percent cover of woody plant canopy with the most robust plants growing in full sun (Fowler 2010, pp
of the Devils River or Edwards formations and Glen Rose formations in central Texas. These juniper-oak woodlands and shrublands experience hot, often dry summers and mild winters with bimodal (spring and fall) precipitation patterns. Optimal microsites for the bracted twistflower have less than 50 percent cover of woody plant canopy with the most robust plants growing in full sun (Fowler 2010, pp. 10-12; Leonard 2010, pp. 30-32; Ramsey 2010, pp. 10-13, 20; Leonard and Van Auken 2013, pp. 276-285). However, in areas with dense populations of white-tailed deer and other herbivores, few individuals survive except where they are protected from herbivory by a cover of dense, spiny understory vegetation (McNeal 1989, p. 17; Damude and Poole 1990, pp. 29 -30; Poole et al. 2007, p. 470; Leonard 2010, p. 63).
Reproduction
Bracted twistflower is an annual species sustained through its reserve of
Bracted twistflower reproduces primarily by outcrossing between individuals that are not closely related; self-pollination produces only small amounts of seeds. Fertilization requires that two or more sexually compatible individuals are located within the forage range of native bee pollinators. The longevity of seed viability has not been determined, although at least some seeds remain viable in the soil for at least 7 years (Service 2021, p. 12). The known pollinators of bracted twistflower are leafcutter bees ( Megachile spp.) (Dieringer (1991, pp. 341-343), which have an estimated forage range of 600 meters to 3 kilometers (0.37 to 1.86 miles) (Mitchell 1936, pp. 124-125; Gathmann and Tscharntke 2002, pp. 760-761; Greenleaf et al. 2007, p. 593; Discover Life 2019); sweat bees (family Halictidae ) may also be effective pollinators (Service 2021, p. 5), but due to their smaller size have correspondingly smaller forage ranges
ringer (1991, pp. 341-343), which have an estimated forage range of 600 meters to 3 kilometers (0.37 to 1.86 miles) (Mitchell 1936, pp. 124-125; Gathmann and Tscharntke 2002, pp. 760-761; Greenleaf et al. 2007, p. 593; Discover Life 2019); sweat bees (family Halictidae ) may also be effective pollinators (Service 2021, p. 5), but due to their smaller size have correspondingly smaller forage ranges. Sexual reproduction also increases genetic diversity, and thus representation, which allows populations to be more likely to adapt and survive when confronted with new pathogens, competitors, and changing environmental conditions. For these reasons, successful reproduction likely requires clustering of genetically diverse individuals within habitats that also support leafcutter bees, sweat bees, and other native bee species.
Fall and winter rainfall stimulate bracted twistflower seed germination; successive rainfall events that allow soil moisture to persist may have greater effect than one or two heavy rains. In addition to rain, other factors appear to stimulate germination, such as the removal of competing vegetation, and possibly fire during a previous season.
Minimum Viable Population Size
Populations of bracted twistflower must be large enough to have a high probability of surviving a prescribed period of time. For example, Mace and Lande (1991, p. 151) propose that species or populations be classified as vulnerable when the probability of persisting 100 years is less than 90 percent. This metric of population resilience is called minimum viable population (MVP). We adapted the method published in Pavlik (1996, p. 137) to estimate an MVP for bracted twistflower of about 1,800 individuals. This estimate of MVP is based only on numbers of mature, flowering individuals because juveniles that die before they reproduce do not contribute to the effective population size or future genetic diversity
population resilience is called minimum viable population (MVP). We adapted the method published in Pavlik (1996, p. 137) to estimate an MVP for bracted twistflower of about 1,800 individuals. This estimate of MVP is based only on numbers of mature, flowering individuals because juveniles that die before they reproduce do not contribute to the effective population size or future genetic diversity.
Current Condition
Our assessment of the current species viability of bracted twistflower is based on its resiliency, redundancy, and representation. We ranked the current conditions of bracted twistflower EOs as high, medium, low, or extirpated based on the following characteristics: The proportion of potential populations where habitat is intact (described above); the population sizes and trends (if known) in remaining intact habitats; genetic diversity and inbreeding coefficients (if known); and the current levels of monitoring, vegetation management, and protection from development, herbivores, and recreational impacts on the remaining intact habitats. The current condition of each EO is based upon the cumulative effects of these factors.
Resiliency
Our review of the TXNDD EO records (TXNDD 2018) indicates that relatively large pulses of bracted twistflower plants emerge in specific areas (Source Features) during relatively few years, while during most years few or no plants emerge. This wide annual variation in germination makes it very difficult to determine the species' population sizes and demographic trends (Service 2021, pp. 22-23, appendix A). However, one indicator of the status of bracted twistflower populations is the condition of their habitats. We define potential population size as the maximum numbers observed in specific areas during “pulse” years, when optimal conditions stimulate the greatest amounts of seed germination, establishment, and survival to successful reproduction. Thus, our estimate of the species' status is based in part on the potential populations remaining in intact habitats
lations is the condition of their habitats. We define potential population size as the maximum numbers observed in specific areas during “pulse” years, when optimal conditions stimulate the greatest amounts of seed germination, establishment, and survival to successful reproduction. Thus, our estimate of the species' status is based in part on the potential populations remaining in intact habitats. The potential total number of individuals at the 17 naturally occurring EOs observed since 1989 is 12,764 (not including 120 planted at the experimental population at EO 33). Since 1989, 14 percent of bracted twistflower habitat (a potential population of 1,780 plants) has been completely destroyed in portions of six EOs; 19 percent of bracted twistflower habitat (a potential population of 2,496 plants) has been partially destroyed in portions of five EOs; and 67 percent (a potential population of 8,488 plants) remains intact in portions of 15 naturally occurring EOs (note that each EO can have intact, partially destroyed, and destroyed portions, so the total is greater than the number of EOs). Nevertheless, this estimate reflects only the losses due to habitat development, and does not account for populations that may have declined due to excessive herbivory or juniper competition.
Only four of the remaining EOs have potential populations of at least 50 percent of the estimated MVP value of 1,800 individuals. These medium resilient populations are Barton Creek Greenbelt and Wilderness Park (EO 17) and Rancho Diana (EO 31), which are protected natural areas managed by the City of Austin and City of San Antonio, respectively; Laurel Canyon (EO 25) is protected from development and land use change through a City of San Antonio conservation easement; and landowners voluntarily conserve a portion of Medina Lake (EO 18). The City of Austin also protects Ullrich (EO 7) from development and land use change (Texas Parks and Wildlife Department 2018, p
areas managed by the City of Austin and City of San Antonio, respectively; Laurel Canyon (EO 25) is protected from development and land use change through a City of San Antonio conservation easement; and landowners voluntarily conserve a portion of Medina Lake (EO 18). The City of Austin also protects Ullrich (EO 7) from development and land use change (Texas Parks and Wildlife Department 2018, p. 1), although the potential maximum population is about 27 percent of the estimated MVP level. Gus Fruh (EO 36) is small, but due to its proximity to EO 17 along Barton Creek, might be considered part of a Barton Creek metapopulation. Mt. Bonnell City Park (EO 9), Garner SP (EO 10), Eisenhower City Park (EO 23), Valburn/Bull Creek District Park (EO 35), and Falls Ranch (no EO number) are all currently far below the MVP level. Four EOs have been mostly lost to development: Cat Mountain (EO 2), East Medina (EO 8), Mt. Bonnell City Park, and Valburn/Bull Creek. Two EOs have been completely lost to development: Mesa (EO 21) and Rough Hollow (EO 32). No individuals have been seen in recent years at two additional EOs, Bright Leaf (EO 26) and Upper Long Canyon (EO 24), nor at the experimental population at Vireo Preserve (EO 33). In summary, none of the EOs of bracted twistflower have reached the MVP level in the last decade, most have low resiliency, many have gradually declined over the years that they have been monitored, and six EOs have been extirpated or very nearly extirpated.
Redundancy and Representation
Bracted twistflower currently possesses significant genetic diversity at the species level, but populations are genetically distinct and there is no gene
Representation areas are sectors of a species' geographic range where important constituents of its genetic and ecological diversity occur. The known EOs of bracted twistflower are clustered in three geographic areas separated from each other by 50 km (30 mi) or more
rently possesses significant genetic diversity at the species level, but populations are genetically distinct and there is no gene
Representation areas are sectors of a species' geographic range where important constituents of its genetic and ecological diversity occur. The known EOs of bracted twistflower are clustered in three geographic areas separated from each other by 50 km (30 mi) or more. Slight differences in day length, solar elevation, temperature, and precipitation occur over the species' range from northeast to southwest. Austin has more moderate summer and winter temperatures, 40 percent fewer days of freezing weather, and 40 percent greater annual rainfall, compared to Uvalde County. These climate differences also create variation in the structure and composition of associated vegetation. Pepper (2010, pp. 4, 15) identified major, distinct clusters of genetic diversity in Medina County and in the Austin area . Based on this genetic data and the geographic clustering of populations, we identified three representation areas in the northeastern, central, and western portions of the species' range (Service 2021, Figure 9).
Two EOs are extirpated (EO 21 and EO 32), and five EOs have low condition ranks and negligible contributions to redundancy. The northeast representation area has six EOs with high or medium condition ranks, conferring an intermediate degree of population redundancy within this area. The central representation area also has intermediate redundancy, because it has four EOs with high- or medium- condition ranks. In the west representation area, only EO 10 has a medium condition rank, and no population pulses have been observed there in recent years. This representation area appears to have very low redundancy; however, few surveys have been conducted in that area, so undiscovered populations might still exist.
In summary, bracted twistflower has four EOs with medium resiliency and no highly resilient EOs. Two representation areas have intermediate redundancy
condition rank, and no population pulses have been observed there in recent years. This representation area appears to have very low redundancy; however, few surveys have been conducted in that area, so undiscovered populations might still exist.
In summary, bracted twistflower has four EOs with medium resiliency and no highly resilient EOs. Two representation areas have intermediate redundancy. Genetic representation at the species level is adequate, but 40 to 50 percent of EOs had low genetic diversity and high inbreeding, and inbreeding also occurred in three larger populations. The species has lost all or parts of six EOs and one-third of its potential population size over the last 30 years.
Risk Factors
A primary driver of the bracted twistflower's status is habitat loss due to urban and residential land development (McNeal 1989, p. 17; Damude and Poole 1990, p. 51; Zippin 1997, p. 229; Fowler 2010, p. 2; Pepper 2010, p. 5). A number of cities, including Austin, San Marcos, New Braunfels, and San Antonio, were established along the Balcones Escarpment due to the prevalence of springs. This area, known as the Interstate 35 corridor, is one of the fastest-growing urban complexes in the United States. Urban development reduces the redundancy and representation of the bracted twistflower and has consumed all or most of the habitat at six EOs of the bracted twistflower.
Habitat changes leading to lower sunlight intensity in the existing habitat are another threat to the bracted twistflower as growth and reproduction of the species, and thus resilience, increases with higher light intensity and duration (Fowler 2010, pp. 1-18; Leonard 2010, pp. 1-86; Ramsey 2010, pp. 1-35; Leonard and Van Auken 2013, pp. 276-285). Bracted twistflower habitats have likely experienced a decline in the frequency of wildfire, which has allowed Ashe juniper and other woody plant cover to increase within most bracted twistflower populations (Bray 1904, pp. 14-15, 22-23; Fonteyn et al. 1988, p. 79; Fowler et al. 2012, pp
Fowler 2010, pp. 1-18; Leonard 2010, pp. 1-86; Ramsey 2010, pp. 1-35; Leonard and Van Auken 2013, pp. 276-285). Bracted twistflower habitats have likely experienced a decline in the frequency of wildfire, which has allowed Ashe juniper and other woody plant cover to increase within most bracted twistflower populations (Bray 1904, pp. 14-15, 22-23; Fonteyn et al. 1988, p. 79; Fowler et al. 2012, pp. 1518-1521). These increases in woody plant cover reduce the growth and reproduction of bracted twistflowers.
Severe herbivory by white-tailed deer and introduced ungulates is a significant factor affecting the status of bracted twistflower throughout the species' range, except where populations are protected from deer by fencing or through intensive herd management (McNeal 1989, p. 17; Damude and Poole 1990, pp. 52-53; Dieringer 1991, p. 341; Zippin 1997, pp. 39-197, 227; Leonard 2010, pp. 36-43; Fowler 2014, pp. 17, 19). Herbivory is exacerbated by the extremely high deer densities in the Edwards Plateau of Texas (Zippin 1997, p. 227).
Both permitted and unauthorized recreation affects the species' survival at several protected natural areas, as well as on private lands. Hiking and mountain bike trails have impacted the populations at Mt. Bonnell City Park, Barton Creek Preserve, Garner State Park, and Bull Creek Park through trampling of the herbaceous vegetation and severe soil erosion where trails cut directly through occupied habitat (McNeal 1989, p. 19; Fowler 2010, p. 2; Bracted Twistflower Working Group 2010, p. 3; Pepper 2010, pp. 5, 15, 17).
Small, isolated populations are less resilient and more vulnerable to catastrophic losses caused by random fluctuations in recruitment or variations in rainfall or other environmental factors (Service 2016, p. 20). Small populations are also less able to overwhelm herbivores to ensure replenishment of the soil seed reserve (Service 2021, p. 33)
king Group 2010, p. 3; Pepper 2010, pp. 5, 15, 17).
Small, isolated populations are less resilient and more vulnerable to catastrophic losses caused by random fluctuations in recruitment or variations in rainfall or other environmental factors (Service 2016, p. 20). Small populations are also less able to overwhelm herbivores to ensure replenishment of the soil seed reserve (Service 2021, p. 33). In addition to population size, it is likely that population density also influences population viability, because reproduction requires genetically compatible individuals to be clustered within the forage range of the native bee pollinators (Service 2021, p. 33). Small, reproductively isolated populations are also more susceptible to the loss of genetic diversity, genetic drift, and inbreeding (Barrett and Kohn 1991, pp. 3-30). This may reduce the ability of the species or population to resist pathogens and parasites, adapt to changing environmental conditions, or colonize new habitats. More than half of the EOs observed since 1989 are at risk due to the demographic consequences of small population sizes (significantly below the estimated MVP level of 1,800 individuals), and many of the remaining populations have very little genetic diversity and relatively high levels of inbreeding (Pepper 2010, pp. 13, 15). The species as a whole still possesses significant genetic diversity (Pepper 2010, pp. 4, 11, 15), but several of the core reservoirs of the species' genetic diversity occur on private lands and may be lost to development.
Projections of the Species Future Viability
The SSA projects viability during two future periods, from 2030 to 2040 and from 2050 to 2074. We chose these time frames because they represent the likely minimum and maximum lengths of time that seeds could remain viable in the soil, and therefore the potential of declining EOs to recover from viable seeds in the soil seed reserve
t to development.
Projections of the Species Future Viability
The SSA projects viability during two future periods, from 2030 to 2040 and from 2050 to 2074. We chose these time frames because they represent the likely minimum and maximum lengths of time that seeds could remain viable in the soil, and therefore the potential of declining EOs to recover from viable seeds in the soil seed reserve. Although we do not know the maximum length of time that bracted twistflower seeds can remain viable in the soil seed reserve, observations of the experimental population at Vireo Preserve reveal that at least some seeds are viable after seven
The projections of future viability also considered three different scenarios representing an improvement over current conditions, continuation of current trends, or deterioration beyond current conditions. These scenarios were based on seven components that influence this species' status and their cumulative effects on the species: The extent of conservation support, effects of regional development, survey results, documentation of the geographic range, effectiveness of habitat management, effectiveness of population management, and effects of climate changes. Table 2 summarizes the projected species viability during each of the two time frames and under each of the three scenarios. Under the “improvement” scenario, the number of EOs in high condition, currently 5, would increase to 10 by 2030-2040 and to 13 by 2050-2074 leading to an increase in species' resiliency. In this scenario species' redundancy and representation remain stable. Under the “continue” scenario, the number of extirpated EOs would increase to four by 2030-2040 and to 10 by 2050-2074 leading to a loss of redundancy. Both EOs in the West Representation Area would be extirpated by 2050-2074 leading to a reduction in species' representation. Conditions within 15 EOs would deteriorate under this scenario, leading to a reduction in species' resiliency
emain stable. Under the “continue” scenario, the number of extirpated EOs would increase to four by 2030-2040 and to 10 by 2050-2074 leading to a loss of redundancy. Both EOs in the West Representation Area would be extirpated by 2050-2074 leading to a reduction in species' representation. Conditions within 15 EOs would deteriorate under this scenario, leading to a reduction in species' resiliency. The “deterioration” scenario projects extirpation of 11 and 15 EOs during these periods, respectively, leading to a significant reduction in species redundancy and representation. By 2050-2074 all EOs in the West Representation area would be extirpated with only two remaining in the Northeast Representation Area and one in the Central Representation Area. Under this scenario, species resiliency declines across all sites. For more information, see the bracted twistflower SSA report (Service 2021, pp. 51-66). These scenarios should not be interpreted as mutually exclusive. The components of the scenarios will interact independently; future viability will likely result from a combination of conditions analyzed in these scenarios. For example, conservation support and habitat management could be better than expected by 2050, but climate changes and regional growth could have more severe impacts than expected.
Table 2—Projected Viabilities of Bracted Twistflower During Two Future Time Frames and Under Three Scenarios EO No. Current condition rank Future scenarios Improvement Period/rank Current trends continue Period/rank Deterioration Period/rank Northeast Representation Area 2 Low 2030-2040: Low 2030-2040: Low 2030-2040: Extirpated. 2050-2074: Medium 2050-2074: Extirpated 2050-2074: Extirpated. 7 High 2030-2040: High 2030-2040: High 2030-2040: Low. 2050-2074: High 2050-2074: High 2050-2074: Low. 9 Medium 2030-2040: High 2030-2040: Low 2030-2040: Extirpated. 2050-2074: High 2050-2074: Extirpated 2050-2074: Extirpated. 17 High 2030-2040: High 2030-2040: High 2030-2040: Low
ow 2030-2040: Low 2030-2040: Low 2030-2040: Extirpated. 2050-2074: Medium 2050-2074: Extirpated 2050-2074: Extirpated. 7 High 2030-2040: High 2030-2040: High 2030-2040: Low. 2050-2074: High 2050-2074: High 2050-2074: Low. 9 Medium 2030-2040: High 2030-2040: Low 2030-2040: Extirpated. 2050-2074: High 2050-2074: Extirpated 2050-2074: Extirpated. 17 High 2030-2040: High 2030-2040: High 2030-2040: Low. 2050-2074: High 2050-2074: Medium 2050-2074: Low. 21 Extirpated 2030-2040: Extirpated 2030-2040: Extirpated 2030-2040: Extirpated. 2050-2074: Extirpated 2050-2074: Extirpated 2050-2074: Extirpated. 26 Low 2030-2040: Medium 2030-2040: Extirpated 2030-2040: Extirpated. 2050-2074: Medium 2050-2074: Extirpated 2050-2074: Extirpated. 32 Extirpated 2030-2040: Medium 2030-2040: Extirpated 2030-2040: Extirpated. 2050-2074: Medium 2050-2074: Extirpated 2050-2074: Extirpated. 33 Low 2030-2040: Medium 2030-2040: Extirpated 2030-2040: Extirpated. 2050-2074: High 2050-2074: Extirpated 2050-2074: Extirpated. 35 Medium 2030-2040: High 2030-2040: Low 2030-2040: Low. 2050-2074: High 2050-2074: Low 2050-2074: Extirpated. 36 High 2030-2040: High 2030-2040: Medium 2030-2040: Low. 2050-2074: High 2050-2074: Low 2050-2074: Extirpated. xx 1 Medium 2030-2040: Medium 2030-2040: Low 2030-2040: Extirpated. 2050-2074: High 2050-2074: Extirpated 2050-2074: Extirpated. Central Representation Area 8 Low 2030-2040: Medium 2030-2040: Low 2030-2040: Extirpated. 2050-2074: Extirpated 2050-2074: Extirpated. 18 Medium 2030-2040: High 2030-2040: Medium 2030-2040: Low. 2050-2074: High 2050-2074: Low 2050-2074: Extirpated. 23 Medium 2030-2040: High 2030-2040: Low 2030-2040: Extirpated. 2050-2074: High 2050-2074: Low 2050-2074: Extirpated. 25 High 2030-2040: High 2030-2040: Medium 2030-2040: Low. 2050-2074: High 2050-2074: Low 2050-2074: Extirpated. 31 High 2030-2040: High 2030-2040: High 2030-2040: Medium. 2050-2074: High 2050-2074: High 2050-2074: Low. West Representation Area 10 Medium 2030-2040: High 2030-2040: Low 2030-2040: Extirpated
h 2030-2040: Low 2030-2040: Extirpated. 2050-2074: High 2050-2074: Low 2050-2074: Extirpated. 25 High 2030-2040: High 2030-2040: Medium 2030-2040: Low. 2050-2074: High 2050-2074: Low 2050-2074: Extirpated. 31 High 2030-2040: High 2030-2040: High 2030-2040: Medium. 2050-2074: High 2050-2074: High 2050-2074: Low. West Representation Area 10 Medium 2030-2040: High 2030-2040: Low 2030-2040: Extirpated. 2050-2074: High 2050-2074: Extirpated 2050-2074: Extirpated. 24 Low 2030-2040: Medium 2030-2040: Low 2030-2040: Extirpated. 2050-2074: High 2050-2074: Extirpated 2050-2074: Extirpated. 1 This newly-discovered site does not yet have in EO ID or EO number in the TXNDD. We note that, by using the SSA framework to guide our analysis of the scientific information documented in the SSA report, we have not only analyzed individual effects on the species, but we have also analyzed their potential cumulative effects. We incorporate the cumulative effects into our SSA analysis when we characterize the current and future condition of the species. To assess the current and future condition of the species, we undertake an iterative analysis that encompasses and incorporates the threats individually and then accumulates and evaluates the effects of all the factors that may be influencing the species, including threats and conservation efforts. Because the SSA framework considers not just the presence of the factors, but to what degree they collectively influence risk to the entire species, our assessment integrates the cumulative effects of the factors and replaces a standalone cumulative effects analysis.
Conservation Efforts
Ten scientific investigations have been completed that contribute to our knowledge of the phenology, reproduction, habitats, ecology, population biology, and population genetics of bracted twistflower
they collectively influence risk to the entire species, our assessment integrates the cumulative effects of the factors and replaces a standalone cumulative effects analysis.
Conservation Efforts
Ten scientific investigations have been completed that contribute to our knowledge of the phenology, reproduction, habitats, ecology, population biology, and population genetics of bracted twistflower. The Bracted Twistflower Working Group, a consortium of federal, state, and local agencies, researchers, and conservation organizations, has met informally at least annually since 2000 and has worked actively to promote the conservation and recovery of this species. The Service, Texas Parks and Wildlife Department (TPWD), the City of Austin, Travis County, the Lower Colorado River Authority, and the Lady Bird Johnson Wildflower Center established a voluntary Memorandum of Agreement to protect, monitor, and restore bracted twistflower and its habitats on Balcones Canyonlands Preserve (BCP) tracts. Five extant EOs and one experimental population are protected through the agreement, including three of the five populations in a high current condition (Table 2). The City of San Antonio has actively protected and managed EOs at Eisenhower Park and Rancho Diana; the latter continues to be one of the largest remaining populations. The City of San Antonio and The Nature Conservancy own a conservation easement to protect 222 ha (549 ac) in Medina County for watershed conservation; this includes EO 25, which has one of the largest extant bracted twistflower populations. All or parts of 11 EOs are located on state or local conservation land.
Determination of the Bracted Twistflower's Status
Section 4 of the Act (16 U.S.C
s. The City of San Antonio and The Nature Conservancy own a conservation easement to protect 222 ha (549 ac) in Medina County for watershed conservation; this includes EO 25, which has one of the largest extant bracted twistflower populations. All or parts of 11 EOs are located on state or local conservation land.
Determination of the Bracted Twistflower's Status
Section 4 of the Act (16 U.S.C. 1533) and its implementing regulations (50 CFR part 424) set forth the procedures for determining whether a species meets the definition of an “endangered species” or a “threatened species.” The Act defines an “endangered species” as a species that is in danger of extinction throughout all or a significant portion of its range, and a “threatened species” as a species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. The Act requires that we determine whether a species meets the definition of endangered species or threatened species because of any of the following factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) Overutilization for commercial, recreational, scientific, or educational purposes; (C) Disease or predation; (D) The inadequacy of existing regulatory mechanisms; or (E) Other natural or manmade factors affecting its continued existence.
Status Throughout All of Its Range
We have carefully assessed the best scientific and commercial information available regarding the past, present, and future threats and the cumulative effect of the threats under the section 4(a)(1) factors to the bracted twistflower.
Bracted twistflower occurs in three geographically separate representation areas, which experience differing regional climate and biotic factors
All of Its Range
We have carefully assessed the best scientific and commercial information available regarding the past, present, and future threats and the cumulative effect of the threats under the section 4(a)(1) factors to the bracted twistflower.
Bracted twistflower occurs in three geographically separate representation areas, which experience differing regional climate and biotic factors. Although threats are currently acting on the bracted twistflower throughout its range, 11 EOs were found to have high or medium resiliency for their current condition, and 11 EOs (including one experimental population) occur on protected, state- or locally-owned conservation lands. Thus, after assessing the best available information, we conclude that the bracted twistflower is not currently in danger of extinction throughout all of its range. We therefore proceed with determining whether the bracted twistflower is likely to become endangered within the foreseeable future throughout all of its range.
For the purpose of this determination, the foreseeable future is 50 years, which corresponds to the climate projections used in the analysis. Under the “current trends continue” scenario, the number of extirpated EOs increases from two to 10. Under the “declining” scenario, 15 EOs will become extirpated, and the condition rank of the remaining three EOs will be low. Development, which results in the permanent loss of habitat, is the most significant threat to bracted twistflower, and this threat is expected to continue into the future. Habitats throughout the species' range have been degraded due to habitat modification and increased browsing pressure from white-tailed deer and introduced ungulates. Threats from habitat loss, habitat modification, increased herbivory, and loss of genetic diversity are cumulative and will likely result in further degradation without management intervention. There is no appreciable gene flow between populations (Pepper 2010, p. 11)
nge have been degraded due to habitat modification and increased browsing pressure from white-tailed deer and introduced ungulates. Threats from habitat loss, habitat modification, increased herbivory, and loss of genetic diversity are cumulative and will likely result in further degradation without management intervention. There is no appreciable gene flow between populations (Pepper 2010, p. 11). Populations of bracted twistflower have declined and are expected to continue to decline into the future. Our analysis
Status Throughout a Significant Portion of Its Range
Under the Act and our implementing regulations, a species may warrant listing if it is in danger of extinction or likely to become so in the foreseeable future throughout all or a significant portion of its range. The court in Center for Biological Diversity v. Everson, 2020 WL 437289 (D.D.C. Jan. 28, 2020) ( Center for Biological Diversity ), vacated the aspect of the Final Policy on Interpretation of the Phrase “Significant Portion of Its Range” in the Endangered Species Act's Definitions of “Endangered Species” and “Threatened Species” (79 FR 37578; July 1, 2014) that provided the Service does not undertake an analysis of significant portions of a species' range if the species warrants listing as threatened throughout all of its range. Therefore, we proceed to evaluating whether the species is endangered in a significant portion of its range—that is, whether there is any portion of the species' range for which both (1) the portion is significant, and (2) the species is in danger of extinction in that portion. Depending on the case, it might be more efficient for us to address the “significance” question or the “status” question first. We can choose to address either question first. Regardless of which question we address first, if we reach a negative answer with respect to the first question that we address, we do not need to evaluate the other question for that portion of the species' range
t portion. Depending on the case, it might be more efficient for us to address the “significance” question or the “status” question first. We can choose to address either question first. Regardless of which question we address first, if we reach a negative answer with respect to the first question that we address, we do not need to evaluate the other question for that portion of the species' range.
Following the court's holding in Center for Biological Diversity, we now consider whether there are any significant portions of the species' range where the species is in danger of extinction now ( i.e., endangered). In undertaking this analysis for the bracted twistflower, we choose to address the status question first—we consider information pertaining to the geographic distribution of the species and the threats that the species faces to identify any portions of the range where the species is endangered.
The statutory difference between an endangered species and a threatened species is the time frame in which the species becomes in danger of extinction; an endangered species is in danger of extinction now while a threatened species is not in danger of extinction now but is likely to become so in the foreseeable future. Thus, we reviewed the best scientific and commercial data available regarding the time horizon for the threats that are driving the bracted twistflower to warrant listing as a threatened species throughout all of its range. We considered whether the threats are geographically concentrated in any portion of the species' range in a way that would accelerate the time horizon for the species' exposure or response to the threats. We examined the following threats: Habitat loss to development (Factor A); changes in fire frequency and the composition and structure of vegetation (Factor A); excessive herbivory by white-tailed deer and other ungulates (Factor C); and demographic and genetic consequences of small, isolated populations (Factor E), including cumulative effects
for the species' exposure or response to the threats. We examined the following threats: Habitat loss to development (Factor A); changes in fire frequency and the composition and structure of vegetation (Factor A); excessive herbivory by white-tailed deer and other ungulates (Factor C); and demographic and genetic consequences of small, isolated populations (Factor E), including cumulative effects.
All of the known threats are present throughout the bracted twistflower's range, but to different degrees in different areas. We identified the western portion of the species' range, consisting of two EOs in Uvalde County, and determined that there is a concentration of threats from browsing of white-tailed deer and other ungulates. These threats are not unique to this area, but are acting at greater intensity here ( e.g., larger populations of white-tailed deer and other ungulates). One EO is fairly large in size and is in medium condition with a moderate level of genetic diversity. The other EO within Uvalde County only has data from one observation in 1997, which documented five plants, and is in low condition. Since the larger population in this portion is in medium condition, this portion is not currently in danger of extinction.
Although some threats to the bracted twistflower are concentrated in Uvalde County, the best scientific and commercial data available does not indicate that the concentration of threats, or the species' responses to the concentration of threats, are likely to accelerate the time horizon in which the species becomes in danger of extinction in that portion of its range. As a result, the bracted twistflower is not in danger of extinction now within Uvalde County. Therefore, we determine, that the species is likely to become in danger of extinction within the foreseeable future throughout all of its range. This is consistent with the courts' holdings in Desert Survivors v. Department of the Interior, No. 16-cv-01165-JCS, 2018 WL 4053447 (N.D. Cal. Aug
of its range. As a result, the bracted twistflower is not in danger of extinction now within Uvalde County. Therefore, we determine, that the species is likely to become in danger of extinction within the foreseeable future throughout all of its range. This is consistent with the courts' holdings in Desert Survivors v. Department of the Interior, No. 16-cv-01165-JCS, 2018 WL 4053447 (N.D. Cal. Aug. 24, 2018), and Center for Biological Diversity v. Jewell, 248 F. Supp. 3d, 946, 959 (D. Ariz. 2017).
Determination of Status
Our review of the best scientific and commercial data available indicates that bracted twistflower meets the Act's definition of a threatened species. Therefore, we propose to list the bracted twistflower as a threatened species in accordance with sections 3(20) and 4(a)(1) of the Act.
Available Conservation Measures
Conservation measures provided to species listed as endangered or threatened species under the Act include recognition, recovery actions, requirements for Federal protection, and prohibitions against certain practices. Recognition through listing results in public awareness and conservation by Federal, State, Tribal, and local agencies; private organizations; and individuals. The Act encourages cooperation with the States and other countries and calls for recovery actions to be carried out for listed species. The protection required by Federal agencies and the prohibitions against certain activities are discussed, in part, below.
The primary purpose of the Act is the conservation of endangered and threatened species and the ecosystems upon which they depend. The ultimate goal of such conservation efforts is the recovery of these listed species so that they no longer need the protective measures of the Act. Section 4(f) of the Act calls for the Service to develop and implement recovery plans for the conservation of endangered and threatened species
e Act is the conservation of endangered and threatened species and the ecosystems upon which they depend. The ultimate goal of such conservation efforts is the recovery of these listed species so that they no longer need the protective measures of the Act. Section 4(f) of the Act calls for the Service to develop and implement recovery plans for the conservation of endangered and threatened species. The recovery planning process involves the identification of actions that are necessary to halt or reverse the species' decline by addressing the threats to its survival and recovery. The goal of this process is to restore listed species to a point where they are secure, self-sustaining, and functioning components of their ecosystems.
Recovery planning consists of preparing draft and final recovery plans, beginning with the development of a recovery outline and making it available to the public within 30 days of a final listing determination. The recovery outline guides the immediate implementation of urgent recovery actions and describes the process to be used to develop a recovery plan. Revisions of the plan may be done to address continuing or new threats to the species, as new substantive information becomes available. The recovery plan also identifies recovery criteria for review of when a species may be ready for reclassification from endangered to http://www.fws.gov/endangered ), or from our Austin Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT ).
Implementation of recovery actions generally requires the participation of a broad range of partners, including other Federal agencies, States, Tribes, nongovernmental organizations, businesses, and private landowners. Examples of recovery actions include habitat restoration ( e.g., restoration of native vegetation), research, captive propagation and reintroduction, and outreach and education
).
Implementation of recovery actions generally requires the participation of a broad range of partners, including other Federal agencies, States, Tribes, nongovernmental organizations, businesses, and private landowners. Examples of recovery actions include habitat restoration ( e.g., restoration of native vegetation), research, captive propagation and reintroduction, and outreach and education. The recovery of many listed species cannot be accomplished solely on Federal lands because their range may occur primarily or solely on non-Federal lands. To achieve recovery of these species requires cooperative conservation efforts on private, State, and Tribal lands.
If this species is listed, funding for recovery actions will be available from a variety of sources, including Federal budgets, State programs, and cost-share grants for non-Federal landowners, the academic community, and nongovernmental organizations. In addition, pursuant to section 6 of the Act, the State of Texas would be eligible for Federal funds to implement management actions that promote the protection or recovery of the bracted twistflower. Information on our grant programs that are available to aid species recovery can be found at: http://www.fws.gov/grants.
Although the bracted twistflower is only proposed for listing under the Act at this time, please let us know if you are interested in participating in recovery efforts for this species. Additionally, we invite you to submit any new information on this species whenever it becomes available and any information you may have for recovery planning purposes (see FOR FURTHER INFORMATION CONTACT ).
Section 7(a) of the Act requires Federal agencies to evaluate their actions with respect to any species that is proposed or listed as an endangered or threatened species and with respect to its critical habitat, if any is designated. Regulations implementing this interagency cooperation provision of the Act are codified at 50 CFR part 402
planning purposes (see FOR FURTHER INFORMATION CONTACT ).
Section 7(a) of the Act requires Federal agencies to evaluate their actions with respect to any species that is proposed or listed as an endangered or threatened species and with respect to its critical habitat, if any is designated. Regulations implementing this interagency cooperation provision of the Act are codified at 50 CFR part 402. Section 7(a)(4) of the Act requires Federal agencies to confer with the Service on any action that is likely to jeopardize the continued existence of a species proposed for listing or result in destruction or adverse modification of proposed critical habitat. If a species is listed subsequently, section 7(a)(2) of the Act requires Federal agencies to ensure that activities they authorize, fund, or carry out are not likely to jeopardize the continued existence of the species or destroy or adversely modify its critical habitat. If a Federal action may affect a listed species or its critical habitat, the responsible Federal agency must enter into consultation with the Service.
Federal agency actions within the species' habitat that may require conference or consultation or both as described in the preceding paragraph include management and any other landscape-altering activities on Federal lands administered by the Federal Highways Administration, U.S.D.A. Natural Resources Conservation Service, U.S. Army Corps of Engineers, Department of Defense-Joint Base San Antonio, and Federal Emergency Management Agency.
It is our policy, as published in the Federal Register on July 1, 1994 (59 FR 34272), to identify to the maximum extent practicable at the time a species is listed, those activities that would or would not constitute a violation of section 9 of the Act. The intent of this policy is to increase public awareness of the effect of a proposed listing on proposed and ongoing activities within the range of the species proposed for listing
he Federal Register on July 1, 1994 (59 FR 34272), to identify to the maximum extent practicable at the time a species is listed, those activities that would or would not constitute a violation of section 9 of the Act. The intent of this policy is to increase public awareness of the effect of a proposed listing on proposed and ongoing activities within the range of the species proposed for listing. The discussion below regarding protecting regulations under section 4(d) complies with our policy.
II. Proposed Rule Issued Under Section 4(d) of the Act
Background
Section 4(d) of the Act contains two sentences. The first sentence states that the Secretary shall issue such regulations as she deems necessary and advisable to provide for the conservation of species listed as threatened. The U.S. Supreme Court has noted that statutory language like “necessary and advisable” demonstrates a large degree of deference to the agency (see Webster v. Doe, 486 U.S. 592 (1988)). Conservation is defined in the Act to mean the use of all methods and procedures which are necessary to bring any endangered species or threatened species to the point at which the measures provided pursuant to the Act are no longer necessary. Additionally, the second sentence of section 4(d) of the Act states that the Secretary may by regulation prohibit with respect to any threatened species any act prohibited under section 9(a)(1), in the case of fish or wildlife, or section 9(a)(2), in the case of plants. Thus, the combination of the two sentences of section 4(d) provides the Secretary with wide latitude of discretion to select and promulgate appropriate regulations tailored to the specific conservation needs of the threatened species. The second sentence grants particularly broad discretion to the Service when adopting the prohibitions under section 9.
The courts have recognized the extent of the Secretary's discretion under this standard to develop rules that are appropriate for the conservation of a species
o select and promulgate appropriate regulations tailored to the specific conservation needs of the threatened species. The second sentence grants particularly broad discretion to the Service when adopting the prohibitions under section 9.
The courts have recognized the extent of the Secretary's discretion under this standard to develop rules that are appropriate for the conservation of a species. For example, courts have upheld rules developed under section 4(d) as a valid exercise of agency authority where they prohibited take of threatened wildlife, or include a limited taking prohibition (see Alsea Valley Alliance v. Lautenbacher, 2007 U.S. Dist. Lexis 60203 (D. Or. 2007); Washington Environmental Council v. National Marine Fisheries Service, 2002 U.S. Dist. Lexis 5432 (W.D. Wash. 2002)). Courts have also upheld 4(d) rules that do not address all of the threats a species faces (see State of Louisiana v. Verity, 853 F.2d 322 (5th Cir. 1988)). As noted in the legislative history when the Act was initially enacted, “once an animal is on the threatened list, the Secretary has an almost infinite number of options available to him with regard to the permitted activities for those species. He may, for example, permit taking, but not importation of such species, or he may choose to forbid both taking and importation but allow the transportation of such species” (H.R. Rep. No. 412, 93rd Cong., 1st Sess. 1973).
Exercising this authority under section 4(d), we have developed a proposed rule that is designed to address the bracted twistflower's specific threats and conservation needs. Although the statute does not require us to make a “necessary and advisable” finding with respect to the adoption of specific prohibitions under section 9, we find that this rule as a whole satisfies the requirement in section 4(d) of the Act to issue regulations deemed necessary and advisable to provide for the conservation of the bracted twistflower
wer's specific threats and conservation needs. Although the statute does not require us to make a “necessary and advisable” finding with respect to the adoption of specific prohibitions under section 9, we find that this rule as a whole satisfies the requirement in section 4(d) of the Act to issue regulations deemed necessary and advisable to provide for the conservation of the bracted twistflower. As discussed above under Summary of Biological Status and Threats, the Service has concluded that the bracted twistflower is likely to
Section 7(a)(2) of the Act requires Federal agencies, including the Service, to ensure that any action they fund, authorize, or carry out is not likely to jeopardize the continued existence of any endangered species or threatened species or result in the destruction or adverse modification of designated critical habitat of such species. In addition, section 7(a)(4) of the Act requires Federal agencies to confer with the Service on any agency action which is likely to jeopardize the continued existence of any species proposed to be listed under the Act or result in the destruction or adverse modification of proposed critical habitat.
If a Federal action may affect a listed species or its critical habitat, the responsible Federal agency (action agency) must enter into consultation with us. Examples of actions that are subject to the section 7 consultation process are actions on State, Tribal, local, or private lands that require a Federal permit (such as a permit from the U.S. Army Corps of Engineers under section 404 of the Clean Water Act (33 U.S.C. 1251 et seq. ) or a permit from the Service under section 10 of the Act) or that involve some other Federal action (such as funding from the Federal Highway Administration, Federal Aviation Administration, or the Federal Emergency Management Agency)
rivate lands that require a Federal permit (such as a permit from the U.S. Army Corps of Engineers under section 404 of the Clean Water Act (33 U.S.C. 1251 et seq. ) or a permit from the Service under section 10 of the Act) or that involve some other Federal action (such as funding from the Federal Highway Administration, Federal Aviation Administration, or the Federal Emergency Management Agency). Federal actions not affecting listed species or critical habitat—and actions on State, Tribal, local, or private lands that are not federally funded, authorized, or carried out by a Federal agency—do not require section 7 consultation.
This obligation does not change in any way for a threatened species with a species-specific 4(d) rule. Actions that result in a determination by a Federal agency of “not likely to adversely affect” continue to require the Service's written concurrence and actions that are “likely to adversely affect” a species require formal consultation and the formulation of a biological opinion.
Provisions of the Proposed 4(d) Rule
This proposed 4(d) rule would provide for the conservation of the bracted twistflower by prohibiting the following activities, except as otherwise authorized or permitted: Importing or exporting; certain acts related to removing, damaging, and destroying; delivering, receiving, transporting, or shipping in interstate or foreign commerce in the course of commercial activity; and selling or offering for sale in interstate or foreign commerce.
As discussed above under Summary of Biological Status and Threats, habitat loss due to urban and residential land development (Factor A), increases in woody plant cover (Factor A), severe herbivory (Factor E), and small, isolated populations (Factor E) affect the status of the bracted twistflower
e course of commercial activity; and selling or offering for sale in interstate or foreign commerce.
As discussed above under Summary of Biological Status and Threats, habitat loss due to urban and residential land development (Factor A), increases in woody plant cover (Factor A), severe herbivory (Factor E), and small, isolated populations (Factor E) affect the status of the bracted twistflower. To protect the species from these threats, in addition to the protections that apply to Federal lands, the 4(d) rule would prohibit a person from removing, cutting, digging up, or damaging or destroying the species on non-Federal lands in knowing violation of any law or regulation of any State or in the course of any violation of a State criminal trespass law. As most populations of the bracted twistflower occur off Federal land, these protections in the 4(d) rule are key to its effectiveness. For example, any damage to the species on non-Federal land in violation of a Texas off-highway vehicle law would be prohibited by the 4(d) rule. Additionally, any damage incurred by the species due to criminal trespass on non-Federal lands would similarly violate the proposed 4(d) rule. As a whole, the proposed 4(d) rule would help in the efforts to recover the bracted twistflower by limiting specific actions that damage individual populations.
We may issue permits to carry out otherwise prohibited activities, including those described above, involving threatened plants under certain circumstances
nal trespass on non-Federal lands would similarly violate the proposed 4(d) rule. As a whole, the proposed 4(d) rule would help in the efforts to recover the bracted twistflower by limiting specific actions that damage individual populations.
We may issue permits to carry out otherwise prohibited activities, including those described above, involving threatened plants under certain circumstances. Regulations governing permits for threatened plants are codified at 50 CFR 17.72, which states that “the Director may issue a permit authorizing any activity otherwise prohibited with regard to threatened species.” That regulation also states, “The permit shall be governed by the provisions of this section unless a special rule applicable to the plant is provided in sections 17.73 to 17.78.” We interpret that second sentence to mean that permits for threatened species are governed by the provisions of section 17.72 unless a special rule, which we have defined to mean a species-specific 4(d) rule, provides otherwise. We recently promulgated revisions to section 17.71 providing that section 17.71 will no longer apply to plants listed as threatened in the future. We did not intend for those revisions to limit or alter the applicability of the permitting provisions in section 17.72, or to require that every species-specific 4(d) rule spell out any permitting provisions that apply to that species and species-specific 4(d) rule. To the contrary, we anticipate that permitting provisions would generally be similar or identical for most species, so applying the provisions of section 17.72 unless a species-specific 4(d) rule provides otherwise would likely avoid substantial duplication
o require that every species-specific 4(d) rule spell out any permitting provisions that apply to that species and species-specific 4(d) rule. To the contrary, we anticipate that permitting provisions would generally be similar or identical for most species, so applying the provisions of section 17.72 unless a species-specific 4(d) rule provides otherwise would likely avoid substantial duplication. Moreover, this interpretation brings section 17.72 in line with the comparable provision for wildlife at 50 CFR 17.32, in which the second sentence states, “Such permit shall be governed by the provisions of this section unless a special rule applicable to the wildlife, appearing in sections 17.40 to 17.48, of this part provides otherwise.” Under 50 CFR 17.12 with regard to threatened plants, a permit may be issued for the following purposes: For scientific purposes, to enhance propagation or survival, for economic hardship, for botanical or horticultural exhibition, for educational purposes, or for other purposes consistent with the purposes and policy of the Act. Additional statutory exemptions from the prohibitions are found in sections 9 and 10 of the Act.
We recognize the special and unique relationship with our State natural resource agency partners in contributing to conservation of listed species. State agencies often possess scientific data and valuable expertise on the status and distribution of endangered, threatened, and candidate species of wildlife and plants. State agencies, because of their authorities and their close working relationships with local governments and landowners, are in a unique position to assist the Services in implementing all aspects of the Act. In this regard, section 6 of the Act provides that the Services shall cooperate to the maximum extent practicable with the States in carrying out programs authorized by the Act
e and plants. State agencies, because of their authorities and their close working relationships with local governments and landowners, are in a unique position to assist the Services in implementing all aspects of the Act. In this regard, section 6 of the Act provides that the Services shall cooperate to the maximum extent practicable with the States in carrying out programs authorized by the Act. Therefore, any qualified employee or agent of a State conservation agency that is a party to a cooperative agreement with the Service in accordance with section 6(c) of the Act, who is designated by his or her agency for such purposes, would be able to conduct activities designed to conserve the bracted twistflower that may result in otherwise prohibited activities without additional authorization.
The Service recognizes the proposed 4(d) rule would allow beneficial and educational aspect of activities with seeds of cultivated plants, which generally enhance the propagation of the species, and therefore would satisfy permit requirements under the Act. The Service intends to monitor the interstate and foreign commerce and import and export of these specimens in a manner that will not inhibit such activities, providing the activities do not represent a threat to the survival of the species in the wild. In this regard, seeds of cultivated specimens would not be subject to the prohibitions above, provided that a statement that the seeds are of “cultivated origin” accompanies the seeds or their container.
Propagation is currently taking place for the bracted twistflower and will continue to be an important recovery tool. This will include collecting seeds from wild populations, following Center for Plant Conservation guidelines and the USFWS-NMFS 2000 Policy Regarding Controlled Propagation of Species Listed Under the Endangered Species Act (65 FR 56916), and propagating them for seed increase, population augmentation, introduction, and research related to the species' recovery
ue to be an important recovery tool. This will include collecting seeds from wild populations, following Center for Plant Conservation guidelines and the USFWS-NMFS 2000 Policy Regarding Controlled Propagation of Species Listed Under the Endangered Species Act (65 FR 56916), and propagating them for seed increase, population augmentation, introduction, and research related to the species' recovery.
Nothing in this proposed 4(d) rule would change in any way the recovery planning provisions of section 4(f) of the Act, the consultation requirements under section 7 of the Act, or the ability of the Service to enter into partnerships for the management and protection of the bracted twistflower. However, interagency cooperation may be further streamlined through planned programmatic consultations for the species between Federal agencies and the Service, where appropriate. We ask the public, particularly State agencies and other interested stakeholders that may be affected by the proposed 4(d) rule, to provide comments and suggestions regarding additional guidance and methods that the Service could provide or use, respectively, to streamline the implementation of this proposed 4(d) rule (see Information Requested, above).
III. Critical Habitat
Background
Critical habitat is defined in section 3 of the Act as:
(1) The specific areas within the geographical area occupied by the species, at the time it is listed in accordance with the Act, on which are found those physical or biological features
(a) Essential to the conservation of the species, and
this proposed 4(d) rule (see Information Requested, above).
III. Critical Habitat
Background
Critical habitat is defined in section 3 of the Act as:
(1) The specific areas within the geographical area occupied by the species, at the time it is listed in accordance with the Act, on which are found those physical or biological features
(a) Essential to the conservation of the species, and
(b) Which may require special management considerations or protection; and
(2) Specific areas outside the geographical area occupied by the species at the time it is listed, upon a determination that such areas are essential for the conservation of the species.
Our regulations at 50 CFR 424.02 define the geographical area occupied by the species as an area that may generally be delineated around species' occurrences, as determined by the Secretary ( i.e., range). Such areas may include those areas used throughout all or part of the species' life cycle, even if not used on a regular basis ( e.g., migratory corridors, seasonal habitats, and habitats used periodically, but not solely by vagrant individuals). Additionally, our regulations at 50 CFR 424.02 define the word “habitat” as follows: “For the purposes of designating critical habitat only, habitat is the abiotic and biotic setting that currently or periodically contains the resources and conditions necessary to support one or more life processes of a species.”
Conservation, as defined under section 3 of the Act, means to use and the use of all methods and procedures that are necessary to bring an endangered or threatened species to the point at which the measures provided pursuant to the Act are no longer necessary
etting that currently or periodically contains the resources and conditions necessary to support one or more life processes of a species.”
Conservation, as defined under section 3 of the Act, means to use and the use of all methods and procedures that are necessary to bring an endangered or threatened species to the point at which the measures provided pursuant to the Act are no longer necessary. Such methods and procedures include, but are not limited to, all activities associated with scientific resources management such as research, census, law enforcement, habitat acquisition and maintenance, propagation, live trapping, and transplantation, and, in the extraordinary case where population pressures within a given ecosystem cannot be otherwise relieved, may include regulated taking.
Critical habitat receives protection under section 7 of the Act through the requirement that Federal agencies ensure, in consultation with the Service, that any action they authorize, fund, or carry out is not likely to result in the destruction or adverse modification of critical habitat. The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve, or other conservation area. Such designation also does not allow the government or public to access private lands. Such designation does not require implementation of restoration, recovery, or enhancement measures by non-Federal landowners. Where a landowner requests Federal agency funding or authorization for an action that may affect a listed species or critical habitat, the Federal agency would be required to consult with the Service under section 7(a)(2) of the Act
rnment or public to access private lands. Such designation does not require implementation of restoration, recovery, or enhancement measures by non-Federal landowners. Where a landowner requests Federal agency funding or authorization for an action that may affect a listed species or critical habitat, the Federal agency would be required to consult with the Service under section 7(a)(2) of the Act. However, even if the Service were to conclude that the proposed activity would result in destruction or adverse modification of the critical habitat, the Federal action agency and the landowner are not required to abandon the proposed activity, or to restore or recover the species; instead, they must implement “reasonable and prudent alternatives” to avoid destruction or adverse modification of critical habitat.
Under the first prong of the Act's definition of critical habitat, areas within the geographical area occupied by the species at the time it was listed are included in a critical habitat designation if they contain physical or biological features (1) which are essential to the conservation of the species and (2) which may require special management considerations or protection. For these areas, critical habitat designations identify, to the extent known using the best scientific and commercial data available, those physical or biological features that are essential to the conservation of the species (such as space, food, cover, and protected habitat). In identifying those physical or biological features that occur in specific occupied areas, we focus on the specific features that are essential to support the life-history needs of the species, including, but not limited to, water characteristics, soil type, geological features, prey, vegetation, symbiotic species, or other features. A feature may be a single habitat characteristic, or a more complex combination of habitat characteristics. Features may include habitat characteristics that support ephemeral or dynamic habitat conditions
al to support the life-history needs of the species, including, but not limited to, water characteristics, soil type, geological features, prey, vegetation, symbiotic species, or other features. A feature may be a single habitat characteristic, or a more complex combination of habitat characteristics. Features may include habitat characteristics that support ephemeral or dynamic habitat conditions. Features may also be expressed in terms relating to principles of conservation biology, such as patch size, distribution distances, and connectivity.
Under the second prong of the Act's definition of critical habitat, we can designate critical habitat in areas outside the geographical area occupied by the species at the time it is listed, upon a determination that such areas are essential for the conservation of the species. The implementing regulations at 50 CFR 424.12(b)(2) further delineate unoccupied critical habitat by setting out three specific parameters: (1) When designating critical habitat, the Secretary will first evaluate areas occupied by the species; (2) the Secretary will only consider unoccupied areas to be essential where a critical
Section 4 of the Act requires that we designate critical habitat on the basis of the best scientific data available. Further, our Policy on Information Standards Under the Endangered Species Act (published in the Federal Register on July 1, 1994 (59 FR 34271)), the Information Quality Act (section 515 of the Treasury and General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)), and our associated Information Quality Guidelines provide criteria, establish procedures, and provide guidance to ensure that our decisions are based on the best scientific data available. They require our biologists, to the extent consistent with the Act and with the use of the best scientific data available, to use primary and original sources of information as the basis for recommendations to designate critical habitat
ation Quality Guidelines provide criteria, establish procedures, and provide guidance to ensure that our decisions are based on the best scientific data available. They require our biologists, to the extent consistent with the Act and with the use of the best scientific data available, to use primary and original sources of information as the basis for recommendations to designate critical habitat.
When we are determining which areas should be designated as critical habitat, our primary source of information is generally the information from the SSA report and information developed during the listing process for the species. Additional information sources may include any generalized conservation strategy, criteria, or outline that may have been developed for the species; the recovery plan for the species; articles in peer-reviewed journals; conservation plans developed by States and counties; scientific status surveys and studies; biological assessments; other unpublished materials; or experts' opinions or personal knowledge.
As the regulatory definition of “habitat” reflects (50 CFR 424.02), habitat is dynamic, and species may move from one area to another over time. We recognize that critical habitat designated at a particular point in time may not include all of the habitat areas that we may later determine are necessary for the recovery of the species. For these reasons, a critical habitat designation does not signal that habitat outside the designated area is unimportant or may not be needed for recovery of the species
e from one area to another over time. We recognize that critical habitat designated at a particular point in time may not include all of the habitat areas that we may later determine are necessary for the recovery of the species. For these reasons, a critical habitat designation does not signal that habitat outside the designated area is unimportant or may not be needed for recovery of the species. Areas that are important to the conservation of the species, both inside and outside the critical habitat designation, will continue to be subject to: (1) Conservation actions implemented under section 7(a)(1) of the Act, (2) regulatory protections afforded by the requirement in section 7(a)(2) of the Act for Federal agencies to ensure their actions are not likely to jeopardize the continued existence of any endangered or threatened species, and (3) the prohibitions found in section 9 of the Act. Federally funded or permitted projects affecting listed species outside their designated critical habitat areas may still result in jeopardy findings in some cases. These protections and conservation tools will continue to contribute to recovery of the species. Similarly, critical habitat designations made on the basis of the best available information at the time of designation will not control the direction and substance of future recovery plans, habitat conservation plans (HCPs), or other species conservation planning efforts if new information available at the time of those planning efforts calls for a different outcome.
Prudency Determination
Section 4(a)(3) of the Act, as amended, and implementing regulations (50 CFR 424.12) require that, to the maximum extent prudent and determinable, the Secretary shall designate critical habitat at the time the species is determined to be an endangered or threatened species. Our regulations (50 CFR 424.12(a)(1)) state that the Secretary may, but is not required to, determine that a designation would not be prudent in the following circumstances:
menting regulations (50 CFR 424.12) require that, to the maximum extent prudent and determinable, the Secretary shall designate critical habitat at the time the species is determined to be an endangered or threatened species. Our regulations (50 CFR 424.12(a)(1)) state that the Secretary may, but is not required to, determine that a designation would not be prudent in the following circumstances:
(i) The species is threatened by taking or other human activity and identification of critical habitat can be expected to increase the degree of such threat to the species;
(ii) The present or threatened destruction, modification, or curtailment of a species' habitat or range is not a threat to the species, or threats to the species' habitat stem solely from causes that cannot be addressed through management actions resulting from consultations under section 7(a)(2) of the Act;
(iii) Areas within the jurisdiction of the United States provide no more than negligible conservation value, if any, for a species occurring primarily outside the jurisdiction of the United States;
(iv) No areas meet the definition of critical habitat; or
(v) The Secretary otherwise determines that designation of critical habitat would not be prudent based on the best scientific data available.
As discussed earlier in this document, there is currently no imminent threat of collection or vandalism identified under Factor B for this species, and identification and mapping of critical habitat is not expected to initiate any such threat. In our SSA report (Service 2021, entire) and proposed listing determination for the bracted twistflower, we determined that the present or threatened destruction, modification, or curtailment of habitat or range is a threat to the bracted twistflower and that those threats in some way can be addressed by section 7(a)(2) consultation measures. The species occurs wholly in the jurisdiction of the United States, and we are able to identify areas that meet the definition of critical habitat
twistflower, we determined that the present or threatened destruction, modification, or curtailment of habitat or range is a threat to the bracted twistflower and that those threats in some way can be addressed by section 7(a)(2) consultation measures. The species occurs wholly in the jurisdiction of the United States, and we are able to identify areas that meet the definition of critical habitat. Therefore, because none of the circumstances enumerated in our regulations at 50 CFR 424.12(a)(1) have been met and because the Secretary has not identified other circumstances for which this designation of critical habitat would be not prudent, we have determined that the designation of critical habitat is prudent for the bracted twistflower.
Critical Habitat Determinability
Having determined that designation is prudent, under section 4(a)(3) of the Act we must find whether critical habitat for the bracted twistflower is determinable. Our regulations at 50 CFR 424.12(a)(2) state that critical habitat is not determinable when one or both of the following situations exist:
(i) Data sufficient to perform required analyses are lacking, or
(ii) The biological needs of the species are not sufficiently well known to identify any area that meets the definition of “critical habitat.”
When critical habitat is not determinable, the Act allows the Service an additional year to publish a critical habitat designation (16 U.S.C. 1533(b)(6)(C)(ii)).
We reviewed the available information pertaining to the biological needs of the species and habitat characteristics where this species is located. This and other information represent the best scientific data available and led us to conclude that the designation of critical habitat is determinable for the bracted twistflower
o publish a critical habitat designation (16 U.S.C. 1533(b)(6)(C)(ii)).
We reviewed the available information pertaining to the biological needs of the species and habitat characteristics where this species is located. This and other information represent the best scientific data available and led us to conclude that the designation of critical habitat is determinable for the bracted twistflower.
Physical or Biological Features Essential to the Conservation of the Species
In accordance with section 3(5)(A)(i) of the Act and regulations at 50 CFR 424.12(b), in determining which areas we will designate as critical habitat from within the geographical area occupied
In considering whether features are essential to the conservation of the species, we may consider an appropriate quality, quantity, and spatial and temporal arrangement of habitat characteristics in the context of the life-history needs, condition, and status of the species. These characteristics include, but are not limited to, space for individual and population growth and for normal behavior; food, water, air, light, minerals, or other nutritional or physiological requirements; cover or shelter; sites for breeding, reproduction, or rearing (or development) of offspring; and habitats that are protected from disturbance.
Summary of Essential Physical or Biological Features
We derive the specific physical or biological features essential to the conservation of the bracted twistflower from studies of the species' habitat, ecology, and life history as described below. Additional information can be found in the SSA report available on http://www.regulations.gov and https://ecos.fws.gov/ecp/species/2856. We have determined that the following physical or biological features are essential to the conservation of the bracted twistflower:
Geological Substrate and Soils
ed twistflower from studies of the species' habitat, ecology, and life history as described below. Additional information can be found in the SSA report available on http://www.regulations.gov and https://ecos.fws.gov/ecp/species/2856. We have determined that the following physical or biological features are essential to the conservation of the bracted twistflower:
Geological Substrate and Soils.
The prevalent Cretaceous geological formations in the Edwards Plateau of central Texas include the Edwards group of formations and its equivalent, the Devils River formation, which replaces the Edwards to the west and south; both of these formations overlie the Glen Rose formation (Maclay and Small 1986, pp. 17-24). Karstic, porous limestones are abundant in the Edwards and Devils River formations, and conversely, the Glen Rose limestones have relatively little porosity. The Edwards Aquifer occupies the porous upper strata, and many seeps and springs occur along the Balcones Escarpment, where the boundary of these upper formations with the Glen Rose is exposed at the surface. Some units of the Edwards, Devils River, and Glen Rose formations are dolomitic, meaning that, in addition to calcium, they also contain significant amounts of magnesium. Bracted twistflower populations occur in close proximity to the exposed boundary of the Edwards or Devils River and Glen Rose formations (McNeal 1989, p. 15; Zippin 1997, p. 223; Carr 2001, p. 1; Pepper 2010, p. 5). Most populations are less than 2 kilometers (km) (1.2 miles (mi)) from this boundary, as seen in less detailed, small-scale geological maps (Fowler 2014, pp. 11-12). A detailed, large-scale geological map of northern Bexar County (Clark et al. 2009) reveals that two bracted twistflower populations (Eisenhower City Park and Rancho Diana) occur in a narrow stratum identified as a basal nodular hydrostratigraphic member of the Kainer Formation, Edwards Group
(mi)) from this boundary, as seen in less detailed, small-scale geological maps (Fowler 2014, pp. 11-12). A detailed, large-scale geological map of northern Bexar County (Clark et al. 2009) reveals that two bracted twistflower populations (Eisenhower City Park and Rancho Diana) occur in a narrow stratum identified as a basal nodular hydrostratigraphic member of the Kainer Formation, Edwards Group. This stratum is immediately below a dolomitic hydrostratigraphic member of the Kainer Formation, and immediately above a cavernous hydrostratigraphic member of the Glen Rose limestone (Service 2021, pp. 8-9, figures 6-8). Populations often occur in horizontal bands where these strata are exposed along slopes. Soils in the immediate vicinity of individual plants are very shallow clays with abundant rock fragments.
Although we do not know why the species is associated with the Edwards-Glen Rose boundary, Fowler (2014, p. 12) proposed two hypotheses: (1) The species depends on increased seepage between these formations; and (2) the species requires higher levels of magnesium ions that leach from dolomitic limestone in the lower strata of the Edwards formation. These hypotheses are not mutually exclusive.
Ecological Community.
Bracted twistflower occurs in native, old-growth juniper-oak woodlands and shrublands along the Balcones Escarpment. Individual plants frequently occur near or under a canopy of Ashe juniper, Texas live oak, Texas persimmon ( Diospyros texana ), Texas mountain laurel, Texas red oak or other trees. In many sites bracted twistflower inhabits dense thickets of evergreen sumac ( Rhus virens ), agarita ( Mahonia trifoliolata ), Roemer acacia ( Acacia roemeriana ), Lindheimer silk-tassel ( Garrya ovata ssp. lindheimeri ), thoroughwort ( Ageratina havanensis ), oreja de ratón ( Bernardia myricifolia ), or other shrubs.
Bracted twistflower is a winter annual plant that persists only where individuals produce enough seeds to sustain a reserve of viable seeds in the soil
ac ( Rhus virens ), agarita ( Mahonia trifoliolata ), Roemer acacia ( Acacia roemeriana ), Lindheimer silk-tassel ( Garrya ovata ssp. lindheimeri ), thoroughwort ( Ageratina havanensis ), oreja de ratón ( Bernardia myricifolia ), or other shrubs.
Bracted twistflower is a winter annual plant that persists only where individuals produce enough seeds to sustain a reserve of viable seeds in the soil. White-tailed deer and introduced ungulates heavily browse the flower stalks of individual plants before they can set seed, thus contributing to the decline of populations. Herbivory threatens the species throughout its range, except where it is protected from deer by fencing or intensive herd management (hunting) (McNeal 1989, p. 17; Damude and Poole 1990, pp. 52-53; Dieringer 1991, p. 341; Zippin 1997, pp. 39-197, 227; Leonard 2010, pp. 36-43; Fowler 2014, pp. 17, 19). The extremely high deer densities in the Edwards Plateau of Texas exacerbate the species' vulnerability to herbivory (Zippin 1997, p. 227).
In sites that are protected from white-tailed deer, the most robust bracted twistflower plants occur where woody plant cover is less dense (Damude and Poole 1990, pp. 29-30; Poole et al. 2007, p. 470). The two largest populations, Laurel Canyon and Rancho Diana, occur in relatively open vegetation of low shrubs and sotol ( Dasylirion texanum ), where there is little or no juniper cover. Laboratory and field experiments demonstrated that growth and reproduction of bracted twistflower benefits from higher light intensity and duration than it receives in many of the extant populations (Fowler 2010, pp. 10-11; Leonard 2010, p. 63; Ramsey 2010, p. 20); its persistence in dense thickets may be due to increased herbivory of the plants growing in more open vegetation (Leonard 2010, p. 63; Ramsey 2010, p. 22). Deer-exclusion cages significantly increased the et al. 1988, p. 79; Service 2021, pp. 12, 29-30)
ight intensity and duration than it receives in many of the extant populations (Fowler 2010, pp. 10-11; Leonard 2010, p. 63; Ramsey 2010, p. 20); its persistence in dense thickets may be due to increased herbivory of the plants growing in more open vegetation (Leonard 2010, p. 63; Ramsey 2010, p. 22). Deer-exclusion cages significantly increased the et al. 1988, p. 79; Service 2021, pp. 12, 29-30).
Bracted twistflower produces seeds primarily through outcrossing (fertilization between different individuals), and therefore depends heavily on pollinators, including a native leafcutter bee, Megachile comata, for reproduction (Dieringer 1991, pp. 341-343). Halictid bees (sweat bees) and other native bee species may also be effective pollinators (Service 2021, p. 5). Therefore, bracted twistflower habitats must also support populations of leafcutter bees and other native bee species that effectively pollinate the species. Native bees in turn require, as sources of pollen and nectar, a diverse, abundant understory of native forb and shrub species that in the past was periodically renewed by wildfires.
In summary, the essential physical and biological features of bracted twistflower are:
(1) Karstic, dolomitic limestones underlain by less permeable limestone strata, where perched aquifers seep to the surface along slopes. These are often found within 2 kilometers of the exposed boundary of the Edwards or Devils River and Glen Rose geological formations;
(2) Native, old-growth juniper-oak woodlands and shrublands along the Balcones Escarpment;
(3) Herbivory from white-tailed deer and introduced ungulates of such low intensity that it does not severely deplete populations prior to seed dispersal;
(4) Tree and shrub canopy gaps that allow direct sunlight to reach the herbaceous plant layer at least 6 hours per day; and
geological formations;
(2) Native, old-growth juniper-oak woodlands and shrublands along the Balcones Escarpment;
(3) Herbivory from white-tailed deer and introduced ungulates of such low intensity that it does not severely deplete populations prior to seed dispersal;
(4) Tree and shrub canopy gaps that allow direct sunlight to reach the herbaceous plant layer at least 6 hours per day; and
(5) Viable populations of native bee species and the abundant, diverse forb and shrub understory that support them.
Special Management Considerations or Protection
When designating critical habitat, we assess whether the specific areas within the geographical area occupied by the species at the time of listing contain features which are essential to the conservation of the species and which may require special management considerations or protection. The features essential to the conservation of this species may require special management considerations or protections to reduce the following threats: Habitat loss due to urban and residential development, increased woody plant cover, severe herbivory by native and introduced ungulates, and trampling and erosion from recreational use. Management activities that could ameliorate these threats include (but are not limited to) juniper thinning, prescribed fire, fencing to exclude deer and other herbivores, herd management of local ungulate populations, and protection from foot and bicycle traffic. These management activities will protect the physical and biological features essential for the conservation of the species by reducing herbivory, maintaining open canopies, protecting the habitat from trampling and erosion, and conserving diverse shrub and forb understory vegetation that supports the species' native bee pollinators.
Criteria Used To Identify Critical Habitat
As required by section 4(b)(2) of the Act, we use the best scientific data available to designate critical habitat
onservation of the species by reducing herbivory, maintaining open canopies, protecting the habitat from trampling and erosion, and conserving diverse shrub and forb understory vegetation that supports the species' native bee pollinators.
Criteria Used To Identify Critical Habitat
As required by section 4(b)(2) of the Act, we use the best scientific data available to designate critical habitat. In accordance with the Act and our implementing regulations at 50 CFR 424.12(b), we review available information pertaining to the habitat requirements of the species and identify specific areas within the geographical area occupied by the species at the time of listing and any specific areas outside the geographical area occupied by the species to be considered for designation as critical habitat.
Areas Occupied at the Time of Listing
We considered the geographic areas occupied by the species at the time of listing to consist of EOs with survey data within the past 7 years or areas in which we confirmed that habitat remained intact using aerial imagery. We know that seeds can remain dormant and viable in the soil of intact sites for at least 7 years. Due to the large proportion of private lands within the range of the species, the majority of known locations occur on publicly-owned conservation lands that can be accessed for surveys. Most of the critical habitat units have been surveyed annually, and the habitats are protected by the cities of Austin and San Antonio. We do not have recent surveys for two sites, EOs 10 and 18 (Garner State Park and Medina Lake). However, we have precise geographic coordinates for these populations collected with Global Positioning System (GPS) instruments. In a Geographic Information System (GIS), we have overlaid the geographic coordinates of these sites on recent orthographically corrected aerial photographs and have determined that the habitats remain intact
two sites, EOs 10 and 18 (Garner State Park and Medina Lake). However, we have precise geographic coordinates for these populations collected with Global Positioning System (GPS) instruments. In a Geographic Information System (GIS), we have overlaid the geographic coordinates of these sites on recent orthographically corrected aerial photographs and have determined that the habitats remain intact.
We designated critical habitat units only at extant EOs that still possess one or more of the physical and biological features that are essential to its conservation. We delineated each critical habitat unit around areas where karstic, dolomitic limestones of the Edwards or Devils River formations overlay the less permeable Glen Rose formation. The elevation ranges and degree of slope of these geological strata vary among EOs. However, because the exposed strata that support bracted twistflower populations are nearly horizontal, we used the elevation range where individuals have been observed at each EO to delineate this essential geological feature over the short distances spanned by that EO Similarly, since seepage from overlying karst aquifers occurs on slopes, we also used the range of slopes where individuals have been observed at each EO to delineate this essential feature at that EO. Thus, we combined the parameters of the observed elevation range and slope range of the species at each EO to delimit each critical habitat unit. However, we excluded any areas that lack natural vegetation, such as roads and buildings, as determined through examination of recent aerial photographs. We also did not designate critical habitat units at EOs that are no longer occupied, or that no longer possess the essential physical and biological features due to development or significant disturbance
EO to delimit each critical habitat unit. However, we excluded any areas that lack natural vegetation, such as roads and buildings, as determined through examination of recent aerial photographs. We also did not designate critical habitat units at EOs that are no longer occupied, or that no longer possess the essential physical and biological features due to development or significant disturbance. Finally, we did not extend critical habitat units beyond areas that have been surveyed, because we cannot determine if they
Areas Outside the Geographic Area Occupied at the Time of Listing
We are not proposing to designate any areas outside the geographic area currently occupied by bracted twistflower because we did not find any unoccupied areas that contained the necessary PBFs and were essential for the conservation of the species. We are designating critical habitat within occupied habitat in all three representation areas, including areas that preserve the populations with the highest resiliency. Therefore, unoccupied areas are not necessary for the recovery of the species.
General Information on the Maps of the Proposed Critical Habitat Designation
When determining proposed critical habitat boundaries, we made every effort to avoid including developed areas such as lands covered by buildings, pavement, and other structures because such lands lack physical or biological features necessary for bracted twistflower. The scale of the maps we prepared under the parameters for publication within the Code of Federal Regulations may not reflect the exclusion of such developed lands. Any such lands inadvertently left inside critical habitat boundaries shown on the maps of this proposed rule have been excluded by text in the proposed rule and are not proposed for designation as critical habitat
bracted twistflower. The scale of the maps we prepared under the parameters for publication within the Code of Federal Regulations may not reflect the exclusion of such developed lands. Any such lands inadvertently left inside critical habitat boundaries shown on the maps of this proposed rule have been excluded by text in the proposed rule and are not proposed for designation as critical habitat. Therefore, if the critical habitat is finalized as proposed, a Federal action involving these lands would not trigger section 7 consultation with respect to critical habitat and the requirement of no adverse modification unless the specific action would affect the physical or biological features in the adjacent critical habitat.
We propose to designate as critical habitat lands that we have determined are occupied at the time of listing ( i.e., currently occupied) and that contain one or more of the physical or biological features that are essential to support life-history processes of the species.
Some units contain all of the identified physical or biological features and support multiple life-history processes. Some units contain only some of the physical or biological features necessary to support the bracted twistflower's particular use of that habitat.
The proposed critical habitat designation is defined by the maps, as modified by any accompanying regulatory text, presented at the end of this document under Proposed Regulation Promulgation. We include more detailed information on the boundaries of the critical habitat designation in the preamble of this document. We will make the coordinates or plot points or both on which each map is based available to the public on http://www.regulations.gov at Docket No. FWS-R2-ES-2021-0013 and at the field office responsible for the designation (see FOR FURTHER INFORMATION CONTACT ).
Proposed Critical Habitat Designation
We are proposing approximately 1,607 acres (ac) (650 hectares (ha)) in three units as critical habitat for the bracted twistflower
t points or both on which each map is based available to the public on http://www.regulations.gov at Docket No. FWS-R2-ES-2021-0013 and at the field office responsible for the designation (see FOR FURTHER INFORMATION CONTACT ).
Proposed Critical Habitat Designation
We are proposing approximately 1,607 acres (ac) (650 hectares (ha)) in three units as critical habitat for the bracted twistflower. The critical habitat areas we describe below constitute our current best assessment of areas that meet the definition of critical habitat for the bracted twistflower. The three areas we propose as critical habitat are: (1) Northeast Unit; (2) Central Unit; and (3) Southwest Unit. Table 2 shows the proposed critical habitat units, the land ownership, and the approximate area of each unit. All units proposed for designation are occupied.
Table 2—Proposed Critical Habitat Units for the Bracted Twistflower [Area estimates reflect all land within critical habitat unit boundaries.] Unit Subunit (conservation area or property name) Property owner Occupied? Critical habitat size Ac Ha 1. Northeast 1a. Barton Creek Park/Wilderness Area (EOs 17, 36) City of Austin Yes 690.50 279.44 1b. Bull Creek Park (EO 35) City of Austin Yes 2.32 0.94 1c. Mount Bonnell Park (EO 9) City of Austin Yes 2.00 0.81 1d. Ullrich Water Treatment Plant (Bee Creek Park) (EO 7) City of Austin Yes 29.92 12.11 2. Central 2a. Eisenhower Park (EO 23) City of San Antonio Yes 78.16 31.63 2b. Rancho Diana (EO 31) City of San Antonio Yes 395.73 160.15 2c. Laurel Canyon Ranch Conservation Easement (EO 25) Laurel C. Canyon Ranch LP; City of San Antonio holds conservation easement Yes 39.59 16.02 2d. Medina River (EO 18) Private Yes 23.28 9.42 3. Southwest Garner State Park (EO 10) Texas Parks and Wildlife Department Yes 345.22 139.71 Totals 1,606.72 650.23 Note: Area sizes may not sum exactly due to rounding. We present brief descriptions of all units, and reasons why they meet the definition of critical habitat for the bracted twistflower, below
olds conservation easement Yes 39.59 16.02 2d. Medina River (EO 18) Private Yes 23.28 9.42 3. Southwest Garner State Park (EO 10) Texas Parks and Wildlife Department Yes 345.22 139.71 Totals 1,606.72 650.23 Note: Area sizes may not sum exactly due to rounding. We present brief descriptions of all units, and reasons why they meet the definition of critical habitat for the bracted twistflower, below.
Unit 1: Northeast
Unit 1 consists of 725 ac (293 ha) of occupied habitat within Travis County, Texas, and is composed of four subunits, which are described below.
Subunit 1a
Barton Creek Greenbelt and Barton Creek Wilderness Park consist of 838.76 ac (339.44 ha) and 1,120.26 ac (453.36 ha) of protected areas, respectively, along Barton Creek within the City of Dendroica chrysoparia ), bracted twistflower, and protected cave invertebrates, while providing appropriate, safe, public recreational access; over 100,000 people visit the Barton Creek units annually for outdoor recreational uses (City of Austin 2007a, pp. 1-11). The specific management objectives relevant to the bracted twistflower include posting educational signs, developing memoranda of cooperation with user groups, conducting outreach to user groups, blocking unauthorized trails, enforcing trail closures, thinning junipers, and controlling exotic species. The City of Austin Wildland Conservation Division monitors the Barton Creek bracted twistflower populations annually (City of Austin 2018); we estimate that this is the second largest known population of this species.
Subunit 1b
Bull Creek District Park, acquired in 1971, is a 47.30-ac (19.14-ha) conservation area owned and managed by the City of Austin Parks and Recreation Department as a unit of the BCP system. We are proposing to designate 2.32 ac (0.94 ha) of this BCP unit as occupied critical habitat for the bracted twistflower (EO 35)
e that this is the second largest known population of this species.
Subunit 1b
Bull Creek District Park, acquired in 1971, is a 47.30-ac (19.14-ha) conservation area owned and managed by the City of Austin Parks and Recreation Department as a unit of the BCP system. We are proposing to designate 2.32 ac (0.94 ha) of this BCP unit as occupied critical habitat for the bracted twistflower (EO 35). This subunit contains the essential physical and biological features of proximity to the geological boundary, old-growth juniper-oak woodlands, and viable native bee populations. Specific threats include juniper encroachment into canopy gaps, white-tailed deer herbivory, infrequent wildfire, off-trail recreational uses, and small population size. Special management needed for the bracted twistflower within this subunit includes white-tailed deer herd management and thinning of juniper trees; if it can be conducted safely, management could include prescribed burning. The primary management goals of this BCP unit are to maintain and improve habitat for golden-cheeked warblers; to protect karst species and other species of concern, including canyon mock-orange ( Philadelphus ernestii ), a rare endemic shrub; and to protect the watershed, water quantity, and water quality (City of Austin 2007b, pp. 1-5). A secondary management goal is to provide safe public access for outdoor recreation. Although the bracted twistflower is not specifically included in the BCP management plan for Bull Creek District Park, a small population was discovered there after the plan was developed and is now monitored annually by the City of Austin Wildland Conservation Division (City of Austin 2018).
Subunit 1c
Mount Bonnell Park (Covert Park at Mount Bonnell) is a 6.07-ac (2.45-ha) conservation area owned and managed by the City of Austin Parks and Recreation Department as a unit of the BCP system. We are proposing to designate 2.00 ac (0.81 ha) of this BCP unit as occupied critical habitat for the bracted twistflower (EO 9)
of Austin Wildland Conservation Division (City of Austin 2018).
Subunit 1c
Mount Bonnell Park (Covert Park at Mount Bonnell) is a 6.07-ac (2.45-ha) conservation area owned and managed by the City of Austin Parks and Recreation Department as a unit of the BCP system. We are proposing to designate 2.00 ac (0.81 ha) of this BCP unit as occupied critical habitat for the bracted twistflower (EO 9). This subunit contains the essential physical and biological features of proximity to the geological boundary, old-growth juniper-oak woodlands, and viable native bee populations. Specific threats include juniper encroachment into canopy gaps, white-tailed deer herbivory, infrequent wildfire, off-trail recreational uses, and small population size. Special management needed for the bracted twistflower within this subunit includes white-tailed deer herd management and thinning of juniper trees; if it can be conducted safely, management could include prescribed burning. The primary management goal for the BCP acreage of Mt. Bonnell is to protect and manage habitat for the bracted twistflower (City of Austin 2007c, pp. 1-4). Management objectives include stopping unauthorized foot traffic into the species' habitat; conducting annual monitoring of the population; increasing the population size; working with adjacent private landowners to protect and manage the species; and removing nonnative, invasive vegetation. The City of Austin Wildland Conservation Division monitors the Mount Bonnell bracted twistflower population annually (City of Austin 2018). This small population is a remnant of a much larger population that extended onto adjacent private land and was subsequently lost to residential development.
Subunit 1d
Ullrich Water Treatment Plant (Bee Creek Park) is a 95.42-ac (38.61-ha) property owned and managed by the City of Austin Water Utility. The Balcones Canyonlands Conservation Plan designated 17.7 ac (7.16 ha) of this property as BCP Habitat Management Areas
mnant of a much larger population that extended onto adjacent private land and was subsequently lost to residential development.
Subunit 1d
Ullrich Water Treatment Plant (Bee Creek Park) is a 95.42-ac (38.61-ha) property owned and managed by the City of Austin Water Utility. The Balcones Canyonlands Conservation Plan designated 17.7 ac (7.16 ha) of this property as BCP Habitat Management Areas. We are proposing to designate 29.92 ac (12.11 ha) of this BCP unit as occupied critical habitat for the bracted twistflower (EO 7); the proposed critical habitat area includes some undeveloped portions of the property that were not included in the BCP Habitat Management Area designation. This subunit contains the essential physical and biological features of proximity to the geological boundary, old-growth juniper-oak woodlands, protection from deer herbivory, and viable native bee populations. Specific threats include juniper encroachment into canopy gaps, infrequent wildfire, and small population size. Special management needed for the bracted twistflower within this subunit includes white-tailed deer herd management and thinning of juniper trees; if it can be conducted safely, management could include prescribed burning. The primary management goals are to protect and maintain habitat for the golden-cheeked warbler, protect karst features and monitor the Bee Creek Cave harvestman ( Texella reddelli ) and other karst invertebrates, protect the population of bracted twistflower at this site, and protect the Little Bee Creek watershed quality (City of Austin 2007d, pp. 1-4). Austin Water Utility constructed a game fence to protect the bracted twistflower population from deer browsing and unauthorized public access. The City of Austin Wildland Conservation Division monitors the Ullrich bracted twistflower population annually (City of Austin 2018).
Unit 2: Central
Unit 2 consists of 537 ac (217 ha) of occupied habitat within Bexar and Medina Counties in Texas
1-4). Austin Water Utility constructed a game fence to protect the bracted twistflower population from deer browsing and unauthorized public access. The City of Austin Wildland Conservation Division monitors the Ullrich bracted twistflower population annually (City of Austin 2018).
Unit 2: Central
Unit 2 consists of 537 ac (217 ha) of occupied habitat within Bexar and Medina Counties in Texas. This unit is composed of four subunits, which are described below.
Subunit 2a
Eisenhower Park is a 324-ac (131-ha) designated natural area in Bexar County owned by the City of San Antonio and managed by San Antonio Parks and Recreation Department (SAPRD). It is bounded on the north by Camp Bullis Military Reservation. We are proposing
Subunit 2b
Rancho Diana is a 1,148-ac (465-ha) natural area in Bexar County acquired by the City of San Antonio through the City's 2005 Edwards Aquifer Protection program. We are proposing to designate 395.73 ac (160.15 ha) as occupied critical habitat for the bracted twistflower at Rancho Diana (EO 31). This subunit contains the essential physical and biological features of proximity to the geological boundary, old-growth juniper-oak woodlands, protection from deer herbivory, tree and shrub canopy gaps, and viable native bee populations. Specific threats include herbivory from white-tailed deer, juniper encroachment into canopy gaps, and infrequent wildfire. Special management needed for the bracted twistflower within this subunit includes white-tailed deer herd management and thinning of juniper trees; if it can be conducted safely, management could include prescribed burning. This property is managed by SAPRD, but currently is not open to the public. SAPRD discovered a large population of bracted twistflower at Rancho Diana in 2010, and subsequently protected the population with a deer-fenced exclosure; however, portions of the population extend beyond this exclosure and are vulnerable to herbivory
t can be conducted safely, management could include prescribed burning. This property is managed by SAPRD, but currently is not open to the public. SAPRD discovered a large population of bracted twistflower at Rancho Diana in 2010, and subsequently protected the population with a deer-fenced exclosure; however, portions of the population extend beyond this exclosure and are vulnerable to herbivory. SAPRD cleared the overstory brush from small portions of the enclosed population in 2017 and 2019, resulting in a large increase in the emergence and seed production of bracted twistflowers within the cleared areas.
Subunit 2c
Laurel Canyon Ranch Conservation Easement is a private property in Medina County owned by Laurel C. Canyon Ranch Limited Partnership, of Houston, Texas. The City of San Antonio Edwards Aquifer Protection Program holds a conservation easement on 549 ac (222 ha) of Laurel Canyon Ranch (City of San Antonio and The Nature Conservancy 2016). About 87 percent of the easement is within the Edwards Aquifer Recharge Zone, and the conservation easement protects water quantity and quality for the City of San Antonio. This subunit is not open to the public. The largest known population of the bracted twistflower was documented at this site in 2001 (Carr 2001; TXNDD 2018), and has been monitored annually by SAPRD since 2018. We are proposing to designate 39.59 ac (16.02 ha) as occupied critical habitat for the bracted twistflower at the Laurel Canyon Ranch Conservation Easement (EO 25). This subunit contains the essential physical and biological features of proximity to the geological boundary, old-growth juniper-oak woodlands, tree and shrub canopy gaps, and viable native bee populations. Specific threats include herbivory from white-tailed deer, juniper encroachment into canopy gaps, and infrequent wildfire
d twistflower at the Laurel Canyon Ranch Conservation Easement (EO 25). This subunit contains the essential physical and biological features of proximity to the geological boundary, old-growth juniper-oak woodlands, tree and shrub canopy gaps, and viable native bee populations. Specific threats include herbivory from white-tailed deer, juniper encroachment into canopy gaps, and infrequent wildfire. Special management needed for the bracted twistflower within this subunit includes white-tailed deer herd management and thinning of juniper trees; if it can be conducted safely, management could include prescribed burning.
Subunit 2d
Medina River is a 722.81-ac (292.52-ha) tract of private property in Medina County owned by Medina Ranch Inc. of San Antonio, Texas. A population of about 1,000 bracted twistflowers was documented there in April 2007 (TXNDD 2018). We are proposing to designate 23.28 ac (9.42 ha), located along bluffs overlooking the Medina River Diversion Lake, as occupied critical habitat for the bracted twistflower (EO 18). This subunit contains the essential physical and biological features of proximity to the geological boundary, old-growth juniper-oak woodlands, tree and shrub canopy gaps, and viable native bee populations. Specific threats include herbivory from white-tailed deer, juniper encroachment into canopy gaps, and infrequent wildfire. Special management needed for the bracted twistflower within this subunit includes white-tailed deer herd management and thinning of juniper trees; if it can be conducted safely, management could include prescribed burning. This subunit is not open to the public.
Unit 3: Southwest
Unit 3 consists of occupied habitat within Uvalde County, Texas. Garner State Park was donated by local landowners to the State of Texas in 1941, and is managed by TPWD. One population of bracted twistflower persists at this very heavily visited, 1,786-ac (723-ha) State park
conducted safely, management could include prescribed burning. This subunit is not open to the public.
Unit 3: Southwest
Unit 3 consists of occupied habitat within Uvalde County, Texas. Garner State Park was donated by local landowners to the State of Texas in 1941, and is managed by TPWD. One population of bracted twistflower persists at this very heavily visited, 1,786-ac (723-ha) State park. We are proposing to designate 345.23 ac (139.71 ha) as occupied critical habitat for the bracted twistflower at Garner State Park (EO 10). This subunit contains the essential physical and biological features of proximity to the geological boundary, old-growth juniper-oak woodlands, tree and shrub canopy gaps, and viable native bee populations. Specific threats include herbivory from white-tailed deer and introduced ungulates, juniper encroachment into canopy gaps, off-trail recreational uses of habitats, and infrequent wildfire. Special management needed for the bracted twistflower within this subunit includes white-tailed deer herd management and thinning of juniper trees; if it can be conducted safely, management could include prescribed burning.
Effects of Critical Habitat Designation
Section 7 Consultation
Section 7(a)(2) of the Act requires Federal agencies, including the Service, to ensure that any action they fund, authorize, or carry out is not likely to jeopardize the continued existence of any endangered species or threatened species or result in the destruction or adverse modification of designated critical habitat of such species. In addition, section 7(a)(4) of the Act requires Federal agencies to confer with the Service on any agency action which is likely to jeopardize the continued existence of any species proposed to be listed under the Act or result in the destruction or adverse modification of proposed critical habitat.
We published a final rule revising the definition of destruction or adverse modification on August 27, 2019 (84 FR 44976)
(4) of the Act requires Federal agencies to confer with the Service on any agency action which is likely to jeopardize the continued existence of any species proposed to be listed under the Act or result in the destruction or adverse modification of proposed critical habitat.
We published a final rule revising the definition of destruction or adverse modification on August 27, 2019 (84 FR 44976). Destruction or adverse
If a Federal action may affect a listed species or its critical habitat, the responsible Federal agency (action agency) must enter into consultation with us. Examples of actions that are subject to the section 7 consultation process are actions on State, Tribal, local, or private lands that require a Federal permit (such as a permit from the U.S. Army Corps of Engineers under section 404 of the Clean Water Act (33 U.S.C. 1251 et seq. ) or a permit from the Service under section 10 of the Act) or that involve some other Federal action (such as funding from the Federal Highway Administration, Federal Aviation Administration, or the Federal Emergency Management Agency). Federal actions not affecting listed species or critical habitat—and actions on State, Tribal, local, or private lands that are not federally funded, authorized, or carried out by a Federal agency—do not require section 7 consultation.
Compliance with the requirements of section 7(a)(2) is documented through our issuance of:
(1) A concurrence letter for Federal actions that may affect, but are not likely to adversely affect, listed species or critical habitat; or
ions on State, Tribal, local, or private lands that are not federally funded, authorized, or carried out by a Federal agency—do not require section 7 consultation.
Compliance with the requirements of section 7(a)(2) is documented through our issuance of:
(1) A concurrence letter for Federal actions that may affect, but are not likely to adversely affect, listed species or critical habitat; or
(2) A biological opinion for Federal actions that may affect and are likely to adversely affect listed species or critical habitat.
When we issue a biological opinion concluding that a project is likely to jeopardize the continued existence of a listed species and/or destroy or adversely modify critical habitat, we provide reasonable and prudent alternatives to the project, if any are identifiable, that would avoid the likelihood of jeopardy and/or destruction or adverse modification of critical habitat. We define “reasonable and prudent alternatives” (at 50 CFR 402.02) as alternative actions identified during consultation that:
(1) Can be implemented in a manner consistent with the intended purpose of the action,
(2) Can be implemented consistent with the scope of the Federal agency's legal authority and jurisdiction,
(3) Are economically and technologically feasible, and
(4) Would, in the Service Director's opinion, avoid the likelihood of jeopardizing the continued existence of the listed species and/or avoid the likelihood of destroying or adversely modifying critical habitat.
Reasonable and prudent alternatives can vary from slight project modifications to extensive redesign or relocation of the project. Costs associated with implementing a reasonable and prudent alternative are similarly variable.
Regulations at 50 CFR 402.16 set forth requirements for Federal agencies to reinitiate formal consultation on previously reviewed actions
ely modifying critical habitat.
Reasonable and prudent alternatives can vary from slight project modifications to extensive redesign or relocation of the project. Costs associated with implementing a reasonable and prudent alternative are similarly variable.
Regulations at 50 CFR 402.16 set forth requirements for Federal agencies to reinitiate formal consultation on previously reviewed actions. These requirements apply when the Federal agency has retained discretionary involvement or control over the action (or the agency's discretionary involvement or control is authorized by law) and, if subsequent to the previous consultation: (1) If the amount or extent of taking specified in the incidental take statement is exceeded; (2) if new information reveals effects of the action that may affect listed species or critical habitat in a manner or to an extent not previously considered; (3) if the identified action is subsequently modified in a manner that causes an effect to the listed species or critical habitat that was not considered in the biological opinion; or (4) if a new species is listed or critical habitat designated that may be affected by the identified action.
Application of the “Destruction or Adverse Modification” Standard
The key factor related to the destruction or adverse modification determination is whether implementation of the proposed Federal action directly or indirectly alters the designated critical habitat in a way that appreciably diminishes the value of the critical habitat as a whole for the conservation of the listed species. As discussed above, the role of critical habitat is to support physical or biological features essential to the conservation of a listed species and provide for the conservation of the species
osed Federal action directly or indirectly alters the designated critical habitat in a way that appreciably diminishes the value of the critical habitat as a whole for the conservation of the listed species. As discussed above, the role of critical habitat is to support physical or biological features essential to the conservation of a listed species and provide for the conservation of the species.
Section 4(b)(8) of the Act requires us to briefly evaluate and describe, in any proposed or final regulation that designates critical habitat, activities involving a Federal action that may violate section 7(a)(2) of the Act by destroying or adversely modifying such habitat, or that may be affected by such designation.
Activities that the Service may, during a consultation under section 7(a)(2) of the Act, consider likely to destroy or adversely modify critical habitat include, but are not limited to, actions that would disturb the soil or underlying rock strata, reduce the diversity and abundance of native bees and bee-pollinated plant species, or diminish the perched aquifers that supply seep moisture to bracted twistflower habitats. Such activities could include, but are not limited to, excavation of soil or underlying rock strata with bulldozers, graders, back-hoes, or excavators within habitats; application of insecticides that kill or impair native bees; application of herbicides that kill or damage native bee-pollinated plants; and displacement of native juniper-oak woodlands with surface cover, such as pavement and buildings, that impede infiltration of rainwater into the soil. These activities could deplete or destroy the soil seed reserve of viable seeds of the bracted twistflower, diminish the abundance of the species' pollinators and thereby reduce seed production and gene flow, or alter the soil and hydrology so that it no longer supports the germination, establishment, and reproduction of the bracted twistflower
that impede infiltration of rainwater into the soil. These activities could deplete or destroy the soil seed reserve of viable seeds of the bracted twistflower, d
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