# 76 FR 27184: Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Lepidium papilliferum (Slickspot Peppergrass)

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-10753

## Section

- **Citation:** 76 FR 27184
- **Heading:** Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Lepidium papilliferum (Slickspot Peppergrass)
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Federal Register / Vol. 76 / 76 FR 27184

## Text

DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 17 [Docket No. FWS-R1-ES-2010-0071; MO 92210-0-0009] RIN 1018-AX16 Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Lepidium papilliferum (Slickspot Peppergrass) AGENCY:
Fish and Wildlife Service, Interior.

ACTION:
Proposed rule.

SUMMARY:
We, the U.S. Fish and Wildlife Service, propose to designate critical habitat for Lepidium papilliferum (slickspot peppergrass) under the Endangered Species Act of 1973, as amended. In total, we are proposing to designate 23,374 hectares (57,756 acres) as critical habitat for Lepidium papilliferum, in Ada, Elmore, Payette, and Owyhee Counties in Idaho.

DATES:
To provide us with adequate time to consider your comments, comments must be received on or before July 11, 2011. Please note that if you are using the Federal eRulemaking Portal (see ADDRESSES section, below), the deadline for submitting an electronic comment is 11:59 p.m. Eastern Standard Time on this date. We must receive requests for public hearings, in writing, at the address shown in the FOR FURTHER INFORMATION CONTACT section by June 24, 2011.

ADDRESSES:
You may submit comments by one of the following methods:
• Federal eRulemaking Portal: http://www.regulations.gov. In the box that reads “Enter Keyword or ID,” enter the docket number for this proposed rule, which is FWS-R1-ES-2010-0071. Check the box that reads “Open for Comment/Submission,” and then click the Search button. You should see an icon that reads “Submit a Comment.” Please ensure that you have found the correct rulemaking before submitting your comment.
• U.S. mail or hand-delivery: Public Comments Processing, Attn: FWS-R1-ES-2010-0071; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, Suite 222; Arlington, VA 22203.
We will post all comments on http://www.regulations.gov
n that reads “Submit a Comment.” Please ensure that you have found the correct rulemaking before submitting your comment.
• U.S. mail or hand-delivery: Public Comments Processing, Attn: FWS-R1-ES-2010-0071; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, Suite 222; Arlington, VA 22203.
We will post all comments on http://www.regulations.gov . This generally means that we will post any personal information you provide us (see the Public Comments section below for more information).
FOR FURTHER INFORMATION CONTACT:
Brian Kelly, State Supervisor, U.S. Fish and Wildlife Service, Idaho Fish and Wildlife Office, 1387 S. Vinnell Way, Room 368, Boise, ID 83709; telephone 208-378-5243; facsimile 208-378-5262. If you use a telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:
Public Comments
We intend that any final action resulting from this proposal 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 government agencies, the scientific community, industry, or other interested parties concerning this proposed rule. We particularly seek comments concerning:
(1) The reasons why we should or should not designate habitat as “critical habitat” under section 4 of the Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et seq. ), including whether there are threats to Lepidium papilliferum from human activity, the degree to which threats from human activity can be expected to increase due to the designation, and whether that increase in threats outweighs the benefit of designation such that the designation of critical habitat may not be prudent.
e Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et seq. ), including whether there are threats to Lepidium papilliferum from human activity, the degree to which threats from human activity can be expected to increase due to the designation, and whether that increase in threats outweighs the benefit of designation such that the designation of critical habitat may not be prudent.
(2) Specific information on:
• The amount and distribution of Lepidium papilliferum habitat;
• What areas occupied at the time of listing and that contain features essential to the conservation of Lepidium papilliferum should be included in the designation and why;
• The habitat components (primary constituent elements) essential to the conservation of the species, such as specific soil characteristics, plant associations, or pollinators, and the quantity and spatial arrangement of these features on the landscape needed to provide for the conservation of the species;
• What areas not occupied at the time of listing are essential for the conservation of the species, if any, and why; and
• Special management considerations or protections that the features essential to the conservation of Lepidium papilliferum may require, including managing for the potential effects of climate change.
(3) Land use designations and current or planned activities in the subject areas and their possible impacts on proposed critical habitat.
(4) Any probable economic, national security, or other relevant impacts of designating any area that may be included in the final designation. We are particularly interested in any impacts on small entities, and the benefits of including or excluding areas that are subject to these impacts.
rrent or planned activities in the subject areas and their possible impacts on proposed critical habitat.
(4) Any probable economic, national security, or other relevant impacts of designating any area that may be included in the final designation. We are particularly interested in any impacts on small entities, and the benefits of including or excluding areas that are subject to these impacts.
(5) Whether the benefits of excluding any particular area from critical habitat outweigh the benefits of including that area in critical habitat under section 4(b)(2) of the Act, after considering both the potential impacts and benefits of the proposed critical habitat designation. Under section 4(b)(2) of the Act, we may exclude an area from critical habitat if we determine that the benefits of such exclusion outweigh the benefits of including that particular area as critical habitat, unless failure to designate that specific area as critical habitat will result in the extinction of the species. We are considering the possible exclusion of areas under private ownership, in particular, as we anticipate the benefits of exclusion may outweigh the benefits of inclusion in those areas. We therefore request specific information on:
• The benefits of including any specific areas in the final designation and supporting rationale,
• The benefits of excluding any specific areas from the final designation and supporting rationale, and
• Whether any specific exclusions may result in the extinction of the species and why (see Exclusions section below).
(5) The use of Public Land Survey System quarter-quarter sections to delineate the proposed critical habitat designation; we used quarter-quarter sections in this proposed rule because they are the most-commonly-used minimum size and method for delineating land ownership boundaries within the range of Lepidium papilliferum .
the extinction of the species and why (see Exclusions section below).
(5) The use of Public Land Survey System quarter-quarter sections to delineate the proposed critical habitat designation; we used quarter-quarter sections in this proposed rule because they are the most-commonly-used minimum size and method for delineating land ownership boundaries within the range of Lepidium papilliferum .
(6) Information on the projected and reasonably likely impacts of climate change on Lepidium papilliferum and on the critical habitat areas we are proposing.
(7) 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 comment.
Our final determination concerning critical habitat for Lepidium papilliferum will take into consideration all written comments we receive during the comment period,
You may submit your comments and materials concerning this proposed rule by one of the methods listed in the ADDRESSES section. We will post your entire comment—including any personal identifying information—on http://www.regulations.gov . If you provide personal identifying information, such as your name, street address, phone number, or e-mail address, 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.
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, or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Idaho Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT ).
Background
Lepidium papilliferum was listed as a threatened species under the Act on October 8, 2009 (74 FR 52014)
umentation we used in preparing this proposed rule, will be available for public inspection on http://www.regulations.gov, or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Idaho Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT ).
Background
Lepidium papilliferum was listed as a threatened species under the Act on October 8, 2009 (74 FR 52014). In this proposed rule, we intend to discuss only those topics directly relevant to the designation of critical habitat for this species. For more detailed information on the genetics and biology of L. papilliferum, please refer to the final listing rule published in the Federal Register on October 8, 2009 (74 FR 52014). Detailed information on L. papilliferum directly relevant to designation of critical habitat is discussed under the Primary Constituent Elements section below.
Species Information
Lepidium papilliferum is a small, flowering plant in the mustard family (Brassicaceae). The plant grows in unique microsite habitats known as slickspots (described below, under “Ecology and Habitat”), which are found within the semiarid sagebrush-steppe ecosystem of southwestern Idaho. The species is endemic to this region, known only from the Snake River Plain and its adjacent northern foothills (an area approximately 145 by 40 kilometers (km) (90 by 25 miles (mi)), or 5,800 square kilometers (km 2 ) (2,250 square miles (mi 2 ))), with a smaller, disjunct population on the Owyhee Plateau (an area of approximately 18 by 19 km (11 by 12 mi), or 342 km 2 (132 mi 2 )). Rangewide, L. papilliferum is associated with slickspots that cover a relatively small cumulative area within the larger sagebrush-steppe ecosystem. Additionally, although L. papilliferum is found almost exclusively in slickspots, very few existing slickspots are occupied by L. papilliferum
ulation on the Owyhee Plateau (an area of approximately 18 by 19 km (11 by 12 mi), or 342 km 2 (132 mi 2 )). Rangewide, L. papilliferum is associated with slickspots that cover a relatively small cumulative area within the larger sagebrush-steppe ecosystem. Additionally, although L. papilliferum is found almost exclusively in slickspots, very few existing slickspots are occupied by L. papilliferum.
Lepidium papilliferum is herbaceous and relatively low-growing, averaging 5 to 20 centimeters (cm) (2 to 8 inches (in)) high, but occasionally reaching up to 40 cm (16 in) in height. It is an intricately branched, tap-rooted plant, with numerous, small, white, four-petalled flowers. Fruits (siliques) are round in outline, flattened, and two-seeded (Moseley 1994, pp. 3, 4; Holmgren et al. 2005, p. 260). The species is monocarpic (it flowers once and then dies) and displays two different life history strategies—an annual form and a biennial form. The annual form reproduces by flowering and setting seed in its first year, and dies within one growing season. The biennial life form initiates growth in the first year as a vegetative rosette, but does not flower and produce seed until the second growing season. The proportion of annuals versus biennials in a population can vary greatly (Meyer et al. 2005, p. 15), but in general annuals appear to outnumber biennials (Moseley 1994, p. 12).
Like many short-lived plants growing in arid environments, above-ground numbers of Lepidium papilliferum individuals can fluctuate widely from one year to the next, depending on seasonal precipitation patterns (Mancuso and Moseley 1998, p. 1; Meyer et al. 2005, pp. 4, 12, 15; Palazzo et al. 2005, p. 9; Menke and Kaye 2006a, p. 8; Menke and Kaye 2006b, pp. 10, 11; Sullivan and Nations 2009, p. 44). Mancuso and Moseley (1998, p. 1) note that sites with thousands of above-ground plants one year may have none the next, and vice versa
ly from one year to the next, depending on seasonal precipitation patterns (Mancuso and Moseley 1998, p. 1; Meyer et al. 2005, pp. 4, 12, 15; Palazzo et al. 2005, p. 9; Menke and Kaye 2006a, p. 8; Menke and Kaye 2006b, pp. 10, 11; Sullivan and Nations 2009, p. 44). Mancuso and Moseley (1998, p. 1) note that sites with thousands of above-ground plants one year may have none the next, and vice versa. Above-ground plants represent only a portion of the population; the seed bank (a reserve of dormant seeds, generally found in the soil) contributes the other portion, and in many years constitutes the majority of the population (Mancuso and Moseley 1998, p. 1).
Ecology and Habitat
Lepidium papilliferum gets its common name, slickspot peppergrass, from its almost exclusive association with slickspot microsite habitats. “Slickspots” are visually distinct openings in the sagebrush-steppe community characterized by soils with high sodium content and distinct clay layers; they tend to be highly reflective and light in color, making them easy to detect on the landscape (Fisher et al. 1996, p. 3). Within the range of L. papilliferum, slickspots cover a relatively small cumulative area within the larger sagebrush-steppe ecosystem. For example, an intense field inventory within the U.S. Air Force Juniper Butte Range in 2002 found that of the 4,480 ha (11,070 ac) surveyed, approximately 1 percent (44.1 ha) (109 ac) consisted of slickspot microsites; of those slickspots, only 4 percent were occupied by individuals of L. papilliferum. It is not known how long slickspots take to form, but it is hypothesized to take several thousands of years (Nettleton and Peterson 1983, p. 193; Seronko 2006, in litt. ). Climate conditions that allowed for the formation of slickspots in southwestern Idaho are thought to have occurred during a wetter Pleistocene period. As slickspots appear to have formed during the Pleistocene and new slickspots are not being formed, the loss of a slickspot is considered a permanent loss
ake several thousands of years (Nettleton and Peterson 1983, p. 193; Seronko 2006, in litt. ). Climate conditions that allowed for the formation of slickspots in southwestern Idaho are thought to have occurred during a wetter Pleistocene period. As slickspots appear to have formed during the Pleistocene and new slickspots are not being formed, the loss of a slickspot is considered a permanent loss. Some slickspots subjected to only light disturbance in the past may apparently be capable of re-forming (Seronko 2006, in litt. ). Disturbances that alter the physical properties of the soil layers, however, such as deep disturbance and the addition of organic matter, may lead to destruction and permanent loss of slickspots.
Several analyses have shown a positive association between above-ground abundance of Lepidium papilliferum and spring precipitation in the same year. More recently, Sullivan and Nations (2009, pp. 30, 41) analyzed 18 years of data and found that both plant density and plant abundance were positively related to mean monthly precipitation in late winter and spring (January through May). This correlation of abundance with spring rainfall is important, as it at least partially explains annual fluctuations in L. papilliferum population numbers. In contrast, precipitation in the fall or early winter may have a negative effect on L. papilliferum abundance the following spring (Meyer et al. 2005, p. 15; Sullivan and Nations 2009, p. 39). It has been suggested this negative relationship may be the result of prolonged flooding of the slickspot microsites, causing et al. 2005, pp. 15-16).
Threats
The primary threat factors that affect the habitat and survival of Lepidium papilliferum in southwest Idaho include the invasion of nonnative annual grasses, such as Bromus tectorum (cheatgrass), and increased fire frequency. Bromus tectorum can impact L
sted this negative relationship may be the result of prolonged flooding of the slickspot microsites, causing et al. 2005, pp. 15-16).
Threats
The primary threat factors that affect the habitat and survival of Lepidium papilliferum in southwest Idaho include the invasion of nonnative annual grasses, such as Bromus tectorum (cheatgrass), and increased fire frequency. Bromus tectorum can impact L. papilliferum directly through competition, but it also acts indirectly on the species by providing continuous fine fuels that contribute to the documented increased frequency and extent of wildfires in southwest Idaho. Frequent wildfires ultimately result in the conversion of the sagebrush-steppe habitat to nonnative annual grasslands, with consequent losses of native species diversity and natural ecological function. This creates a positive feedback loop between nonnative annual grasses and fire, which makes it difficult to separate out the effects that each of these threats independently have on L. papilliferum.
Development also poses a threat to Lepidium papilliferum, both directly through the destruction of populations and loss of slickspot microsites, as well as indirectly through habitat fragmentation. The loss of slickspots is a permanent loss of habitat for L. papilliferum, because the species is specifically adapted to occupy these unique microsite habitats that developed in the Pleistocene era, and new slickspots are no longer being formed (Nettleton and Peterson 1983, pp. 166, 191, 206).
In addition to wildfire, nonnative plants, and development, livestock use poses a secondary threat to Lepidium papilliferum, primarily through mechanical damage to individual plants and slickspot habitats. Livestock trampling can disrupt the soil layers of slickspots, altering slickspot function (Seronko 2004 , in litt.; Colket 2005, p. 34; Meyer et al. 2005, pp. 21-22)
1983, pp. 166, 191, 206).
In addition to wildfire, nonnative plants, and development, livestock use poses a secondary threat to Lepidium papilliferum, primarily through mechanical damage to individual plants and slickspot habitats. Livestock trampling can disrupt the soil layers of slickspots, altering slickspot function (Seronko 2004 , in litt.; Colket 2005, p. 34; Meyer et al. 2005, pp. 21-22). Trampling when slickspots are dry can lead to mechanical damage to the slickspot soil crust, potentially resulting in the invasion of nonnative plants and altering the hydrologic function of slickspots. In water-saturated slickspot soils, trampling by livestock can break through the restrictive clay layer; this is referred to as penetrating trampling (State of Idaho et al. 2006, p. 9). Trampling that alters the soil structure and the functionality of slickspots (Rengasamy et al. 1984, p. 63; Seronko 2004, in litt. ) likely impacts the suitability of these microsites for L. papilliferum. Trampling can also negatively affect the seed bank by pushing seeds too deeply into the soil for subsequent successful germination and emergence. The current livestock management conditions and associated conservation measures address this threat such that it does not appear to pose a significant risk to the species at this time, but more monitoring information is needed to determine the significance of this threat to L. papilliferum rangewide.
Lepidium papilliferum is primarily an outcrossing species, and depends upon a diversity of insect pollinators for more successful fruit production and to maintain genetic variability by genetic exchange with distant populations. Some of the primary threats identified may have indirect effects on L. papilliferum by negatively impacting the native insect populations that the species depends on for pollination and genetic exchange
ily an outcrossing species, and depends upon a diversity of insect pollinators for more successful fruit production and to maintain genetic variability by genetic exchange with distant populations. Some of the primary threats identified may have indirect effects on L. papilliferum by negatively impacting the native insect populations that the species depends on for pollination and genetic exchange. Changes in native habitat caused by residential or agricultural development, or conversion of the native plant community to nonnative species, may impact insect pollinator populations by removing specific food sources or habitats required for breeding or nesting. In addition, habitat isolation and fragmentation resulting from activities such as development or road construction may result in decreased pollination of L. papilliferum from distant sources, possibly resulting in decreased reproductive potential ( e.g., lower seed set) and reduced genetic diversity.
The Owyhee harvester ant was recently identified as a potentially-important seed predator of Lepidium papilliferum. A native species, the harvester ants appear to favor areas dominated by nonnative annual grasses, such as Bromus tectorum, and in the wake of disturbance factors such as wildfire, these ants are beginning to colonize areas that were historically unsuitable for nesting. This expansion is increasingly bringing them into contact with L. papilliferum, which experiences high rates of seed predation by the ants with potential negative consequences for the seed bank and recruitment. Our current understanding of how pervasive harvester ant colonies have become within the range of L. papilliferum, and their overall significance on the long-term viability of the species, is limited due to the short-term nature of the research so far.
For a detailed analysis of the threats to Lepidium papilliferum, please refer to the final listing rule for the species published October 8, 2009 (74 FR 52014)
derstanding of how pervasive harvester ant colonies have become within the range of L. papilliferum, and their overall significance on the long-term viability of the species, is limited due to the short-term nature of the research so far.
For a detailed analysis of the threats to Lepidium papilliferum, please refer to the final listing rule for the species published October 8, 2009 (74 FR 52014).
Previous Federal Actions
On July 15, 2002, we proposed to list Lepidium papilliferum as endangered (67 FR 46441). On January 12, 2007, we published a document in the Federal Register withdrawing the proposed rule (72 FR 1622), based on a determination at that time that listing was not warranted (for a description of Federal actions concerning L. papilliferum between the 2002 proposal to list and the 2007 withdrawal, please refer to the 2007 withdrawal document). On April 6, 2007, Western Watersheds Project filed a lawsuit challenging our decision to withdraw the proposed rule to list L. papilliferum. On June 4, 2008, the U.S. District Court for the District of Idaho (Court) reversed the decision to withdraw the proposed rule, with directions that the case be remanded to the Service for further consideration consistent with the Court's opinion ( Western Watersheds Project v. Kempthorne, Case No. CV 07-161-E-MHW (D. Idaho)).
After issuance of the Court's remand order, we published a public notification of the reinstatement of our July 15, 2002, proposed rule to list Lepidium papilliferum as endangered and announced the reopening of a public comment period on September 19, 2008 (73 FR 54345). To ensure that our review of the species' status was complete, we announced another reopening of the comment period on March 17, 2009, for a period of 30 days (74 FR 11342). On October 8, 2009, we published a final rule (74 FR 52014) listing L. papilliferum as a threatened species throughout its range.
Critical Habitat
Background
Critical habitat is defined in section 3 of the Act as:
345). To ensure that our review of the species' status was complete, we announced another reopening of the comment period on March 17, 2009, for a period of 30 days (74 FR 11342). On October 8, 2009, we published a final rule (74 FR 52014) listing L. papilliferum as a threatened species throughout its range.
Critical Habitat
Background
Critical habitat is defined in section 3 of the Act as:
(i) 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.
(I) Essential to the conservation of the species, and
(II) Which may require special management considerations or protection; and
(ii) 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.
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
Critical habitat receives protection under section 7 of the Act through the prohibition against Federal agencies carrying out, funding, or authorizing the destruction or adverse modification of critical habitat. Section 7(a)(2) requires consultation on Federal actions that may affect 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 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
al actions that may affect 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 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 seeks or requests Federal agency funding or authorization for an action that may affect a listed species or critical habitat, the consultation requirements of section 7(a)(2) would apply, but even in the event of a destruction or adverse modification finding, the Federal action agency and the applicant's obligation is not to restore or recover the species, but to implement reasonable and prudent alternatives to avoid destruction or adverse modification of critical habitat.
For inclusion in a critical habitat designation, the habitat within the geographical area occupied by the species at the time it was listed must contain the primary constituent elements (PCEs) essential to the conservation of the species, and be included only if those features may require special management considerations or protection. Critical habitat designations identify, to the extent known using the best scientific data available, habitat areas that provide essential life-cycle needs of the species (areas on which are found the PCEs laid out in the appropriate quantity and spatial arrangement for the conservation of the species). Under the Act and regulations at 50 CFR 424.12, we can designate critical habitat in areas outside the geographical area occupied by the species at the time it is listed only when we determine that those areas are essential for the conservation of the species and that a designation limited to those areas occupied at the time of listing would be inadequate to ensure the conservation of the species
Under the Act and regulations at 50 CFR 424.12, we can designate critical habitat in areas outside the geographical area occupied by the species at the time it is listed only when we determine that those areas are essential for the conservation of the species and that a designation limited to those areas occupied at the time of listing would be inadequate to ensure the conservation of the species.
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; 114 Stat. 2763A-153-54)), and our associated Information Quality Guidelines (available online at http://www.fws.gov/informationquality/topics/IQAguidelines-final82307.pdf ), 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 developed during the listing process for the species. Additional information sources may include the recovery plan for the species (if available), articles in peer-reviewed journals, conservation plans developed by States and counties, scientific status surveys and studies, biological assessments, or other unpublished materials, including expert opinion or personal knowledge.
Habitat is often dynamic, and species may move from one area to another over time
al information sources may include the recovery plan for the species (if available), articles in peer-reviewed journals, conservation plans developed by States and counties, scientific status surveys and studies, biological assessments, or other unpublished materials, including expert opinion or personal knowledge.
Habitat is often dynamic, and species may move from one area to another over time. In particular, we recognize that climate change may cause changes in areas of occupied habitat. In the Pacific Northwest, regionally averaged temperatures have risen 0.8 degrees Celsius (C) (1.5 degrees Fahrenheit (F)) over the last century (as much as 2 degrees C (4 degrees F) in some areas), and are projected to increase by another 1.5 to 5.5 degrees C (3 to 10 degrees F) over the next 100 years (Mote et al. 2003, p. 54; Karl et al. 2009, p. 135). Arid regions such as the Great Basin where Lepidium papilliferum occurs are likely to become hotter and drier, fire frequency is expected to accelerate, and fires may become larger and more severe (Brown et al. 2004, pp. 382-383; Neilson et al. 2005, p. 150; Chambers and Pellant 2008, p. 31; Karl et al. 2009, p. 83). Under projected future temperature conditions, the cover of sagebrush in the Great Basin region is anticipated to be dramatically reduced (Neilson et al. 2005, p. 154). Warmer temperatures and greater concentrations of atmospheric carbon dioxide create conditions favorable to the invasive annual grass Bromus tectorum, and perpetuate the positive feedback cycle between annual grasses and fire frequency that poses a significant threat to the sagebrush matrix habitat of L. papilliferum (Chambers and Pellant 2008, p. 32; Karl et al. 2009, p. 83).
The direct, long-term impact from climate change to the habitat of Lepidium papilliferum is yet to be determined
favorable to the invasive annual grass Bromus tectorum, and perpetuate the positive feedback cycle between annual grasses and fire frequency that poses a significant threat to the sagebrush matrix habitat of L. papilliferum (Chambers and Pellant 2008, p. 32; Karl et al. 2009, p. 83).
The direct, long-term impact from climate change to the habitat of Lepidium papilliferum is yet to be determined. Under the current climate-change projections discussed above, we anticipate that future climatic conditions will favor further invasion by Bromus tectorum, that fire frequency will continue to increase, and that the extent and severity of fires may increase as well, further changing the species composition of southwest Idaho's sagebrush-steppe habitat.
Although the Intergovernmental Panel on Climate Change (IPCC) projects that the changes to the global climate system in the 21st century will likely be greater than those observed in the 20th century (IPCC 2007, p. 45), there are, nonetheless, limitations to our ability to estimate the scope or magnitude of the effects. Therefore, 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 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 required for recovery of the species.
Areas that are important to the conservation of the species, but are outside the critical habitat designation, will continue to be subject to conservation actions we implement under section 7(a)(1) of the Act. Those areas outside the critical habitat designation that support populations are also subject to the regulatory protections afforded by the section 7(a)(2) jeopardy standard, as determined on the basis of the best available scientific information at the time of the agency action
habitat designation, will continue to be subject to conservation actions we implement under section 7(a)(1) of the Act. Those areas outside the critical habitat designation that support populations are also subject to the regulatory protections afforded by the section 7(a)(2) jeopardy standard, as determined on the basis of the best available scientific information at the time of the agency action. Federally funded or permitted projects affecting listed species outside their designated critical habitat areas may still result in jeopardy findings in some cases. 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
Methods
As required by section 4(b)(2) of the Act, in developing this proposed rule we used the best scientific data available in determining those specific areas within the geographical area occupied at the time of listing that contain the features essential to the conservation of Lepidium papilliferum and that may require special management considerations or protection.
We reviewed available information that pertains to the habitat requirements of this species. These sources of information included, but were not limited to, data used to complete the final rule to list the species (74 FR 52014; October 8, 2009); information from biological surveys, peer reviewed articles, various agency reports and databases for or by the Idaho Natural Heritage Program (INHP), U.S. Bureau of Land Management (BLM), Idaho Army National Guard, State of Idaho, U.S. Air Force, and nongovernmental cooperators; discussions with species experts; and data and information presented in academic research theses
014; October 8, 2009); information from biological surveys, peer reviewed articles, various agency reports and databases for or by the Idaho Natural Heritage Program (INHP), U.S. Bureau of Land Management (BLM), Idaho Army National Guard, State of Idaho, U.S. Air Force, and nongovernmental cooperators; discussions with species experts; and data and information presented in academic research theses. Additionally, we utilized regional Geographic Information System (GIS) data (such as species occurrence data, land use, topography, aerial imagery, soil data, and land ownership maps) for area calculations and mapping.
The long-term probability of the survival and recovery of Lepidium papilliferum is dependent upon protecting existing population sites of sufficient quality and viability to contribute meaningfully to the conservation of the species; maintaining ecological function within these sites, including preserving the integrity of the slickspot soils and connectivity within and between populations in close geographic proximity to one another (to facilitate pollinator activity); and keeping these areas free of major habitat-disturbing activities, including the establishment of invasive, nonnative plant species and frequent wildfire. Because slickspots cover a relatively small cumulative area within the larger sagebrush-steppe matrix, we did not restrict the designation to individual occupied slickspots, but included some adjacent sagebrush-steppe habitat to provide for ecosystem function. This contiguous habitat provides the requisite PCEs for L. papilliferum, including native flowering plants and habitat to support pollinators, and additionally provides the essential feature of habitat free from disturbances, such as invasive species, development, and recreation. The areas we are proposing to designate as critical habitat were all occupied at the time of listing, and provide physical and biological features essential for the conservation of L
lliferum, including native flowering plants and habitat to support pollinators, and additionally provides the essential feature of habitat free from disturbances, such as invasive species, development, and recreation. The areas we are proposing to designate as critical habitat were all occupied at the time of listing, and provide physical and biological features essential for the conservation of L. papilliferum that may require special management considerations or protection. We do not propose to designate areas outside of the geographical area presently occupied by the species.
Our first step in delineating proposed critical habitat units was to identify areas that provide for the conservation of Lepidium papilliferum within the three physiographic regions where the species was known to occur at the time of listing (74 FR 52020; October 8, 2009). These areas include the Boise Foothills, the Snake River Plain and its adjacent northern foothills, and a single disjunct population on the Owyhee Plateau. We are proposing to designate critical habitat in all three physiographic regions to conserve the genetic variability represented by L. papilliferum across its range and because these areas are representative of the entire known historical geographic distribution of the species (50 CFR 424.12(b)(5)).
We then identified areas within these geographic units that were occupied by Lepidium papilliferum at the time of listing utilizing the element occurrence (EO) data provided to us by the Idaho Natural Heritage Program (INHP), and information used in the final rule to list Lepidium papilliferum published in the Federal Register on October 8, 2009 (74 FR 52014). Element occurrences of L. papilliferum are defined by grouping occupied slickspots that occur within 1 km (0.6 mi) of each other; all occupied slickspots within a 1-km (0.6-mi) distance of another occupied slickspot are aggregated into a single EO. The definition of a single EO is based on the distance over which individuals of L
published in the Federal Register on October 8, 2009 (74 FR 52014). Element occurrences of L. papilliferum are defined by grouping occupied slickspots that occur within 1 km (0.6 mi) of each other; all occupied slickspots within a 1-km (0.6-mi) distance of another occupied slickspot are aggregated into a single EO. The definition of a single EO is based on the distance over which individuals of L. papilliferum are believed to be capable of genetic exchange through insect-mediated pollination (Colket and Robertson 2006, pp. 1-2). INHP assigned to each EO an identifying number and a qualitative rank based on measures of population size and habitat quality. Using the EO area ranking system developed by the INHP, we evaluated specific areas to propose for designation as critical habitat (see Criteria Used to Identify Critical Habitat, below). The ranking given to each area takes into account those features that are essential to L. papilliferum, including the presence of slickspots, habitat conditions within and surrounding the area, and the conditions of the surrounding landscape features necessary to support pollination and other life-history requirements. Each EO for L. papilliferum is given a ranking of A, B, C, D, E, F, H, or X by the INHP; higher rankings (the highest rank would be an “A”) indicate sites with greater habitat quality and larger population sizes, which we infer are more likely to persist and sustain the species. As of February 2009, there were no A-ranked EOs of L. papilliferum. Rankings of B, C, and D indicate a decreasing continuum of detectable plants, native plant community, habitat condition, and overall landscape context within 1 km (0.6 mi) of occupied slickspots, with a B ranking signifying a greater number of plants and better habitat conditions and a D ranking signifying few plants and poor conditions. Areas ranked E are those records with confirmed L. papilliferum presence but for which no additional habitat information is available
nts, native plant community, habitat condition, and overall landscape context within 1 km (0.6 mi) of occupied slickspots, with a B ranking signifying a greater number of plants and better habitat conditions and a D ranking signifying few plants and poor conditions. Areas ranked E are those records with confirmed L. papilliferum presence but for which no additional habitat information is available. Areas ranked H indicate historical occurrences, X rankings connote extirpated occurrences, and F rankings indicate areas where no L. papilliferum individuals were found when last visited by a qualified surveyor.
Critical habitat boundaries were initially determined based on the minimum delineation of EO areas. Using GIS, we included an area of approximately 250 meter (m) (820 feet (ft)) around each EO to provide the PCEs for the species, including habitat of sufficient quantity and quality to support pollinators of Lepidium papilliferum in occupied slickspots. This areal extent was chosen to provide the minimum area needed to sustain an active pollinator community for L. papilliferum. This distance is not meant to capture all habitat that is potentially used by pollinators, but it is meant to capture a sufficient area to allow for pollinators to nest, feed, and reproduce in habitat that is adjacent and connected to L. papilliferum EOs. Although the species is served by a variety of pollinators, we delineated this pollinator-use area based on one of L. papilliferum' s important pollinators with a relatively limited flight distance, the solitary bee, assuming that potential pollinators with long-range flight capabilities would be capable of using this habitat as well. Research suggests that solitary bees have fairly small foraging distances (Steffan-Dewenter et al. 2002, pp. 1427-1429; Gathmann and Tscharntke 2002, p. 762); a study by Gathmann and Tscharntke suggested a maximum foraging range between 150 and 600 m (495 and 1,970 ft)
itary bee, assuming that potential pollinators with long-range flight capabilities would be capable of using this habitat as well. Research suggests that solitary bees have fairly small foraging distances (Steffan-Dewenter et al. 2002, pp. 1427-1429; Gathmann and Tscharntke 2002, p. 762); a study by Gathmann and Tscharntke suggested a maximum foraging range between 150 and 600 m (495 and 1,970 ft). Based on this data, we chose 250 m (820 ft) as a reasonable mid-range estimate of the distance needed to provide sufficient L. papilliferum, and some of these insects may travel greater distances than solitary bees; however, these pollinators may also find habitat within 250 m (820 ft) of L. papilliferum EOs. We did not delineate a pollinator use area larger than 250 m (820 ft) around L. papilliferum EOs, because that could include habitats that may not directly contribute to the survival or recovery of the species. In addition to supporting the pollinator community, this area surrounding EOs of L. papilliferum provides the essential feature of habitat free from disturbance, such as development and recreation, for the species.
Using GIS, we intersected the 250-m (820-ft) buffered EOs with a quarter-quarter section shapefile based on the Public Land Survey System. The Public Land Survey System is a rectangular survey system commonly used in the western United States that divides the land into 6-mile square townships (equivalent to 1,554 ha), which are then further subdivided into 1-mile square sections (259 ha). These sections may be surveyed into smaller squares by repeated halving and quartering; a quarter section is 160 ac (65 ha), and the smallest unit normally utilized is a “quarter-quarter section,” equal in size to 40 ac (16 ha) (about 1/16 of a square mile, or 400 m across). Quarter-quarter sections that contained delineated EOs and surrounding buffers were initially identified as proposed critical habitat
tions may be surveyed into smaller squares by repeated halving and quartering; a quarter section is 160 ac (65 ha), and the smallest unit normally utilized is a “quarter-quarter section,” equal in size to 40 ac (16 ha) (about 1/16 of a square mile, or 400 m across). Quarter-quarter sections that contained delineated EOs and surrounding buffers were initially identified as proposed critical habitat. We chose this strategy because, in our judgment, this scale of analysis is the appropriate scale for defining the critical habitat boundaries of this particular species. We based our determination to use this scale of analysis on the following reasons: (1) Quarter-quarter sections are the most-commonly-used minimum size and method for delineating land ownership boundaries within the range of Lepidium papilliferum; (2) the Public Land Survey System is a commonly-used method in Idaho and the sections are easily identified on standard maps, which will assist the public and land management agencies in easily identifying proposed critical habitat areas; (3) quarter-quarter section boundaries are commonly used for partitioning lands for management purposes such as livestock allotment boundaries; and (4) quarter-quarter section descriptions minimize the number of coordinates necessary to define the shapes of the critical habitat units, and avoid a false sense of precision that might be inferred from the use of other mapping tools; we would not consider mapping on a finer scale to represent reliable data with regard to location information.
Primary Constituent Elements (PCEs)
In accordance with subsections 3(5)(A)(i) and 4(b)(1)(A) of the Act and our implementing regulations at 50 CFR 424.12, in determining those areas within the geographical area occupied by the species at the time of listing to propose as critical habitat, we consider the physical or biological features essential to the conservation of the species that may require special management considerations or protection
ce with subsections 3(5)(A)(i) and 4(b)(1)(A) of the Act and our implementing regulations at 50 CFR 424.12, in determining those areas within the geographical area occupied by the species at the time of listing to propose as critical habitat, we consider the physical or biological features essential to the conservation of the species that may require special management considerations or protection. These may include, but are not limited to:
(1) Space for individual and population growth and for normal behavior;
(2) Food, water, air, light, minerals, or other nutritional or physiological requirements;
(3) Cover or shelter;
(4) Sites for breeding, reproduction, or rearing (or development) of offspring; germination, or seed dispersal; and generally
(5) Habitats that are protected from disturbance or are representative of the historic geographical and ecological distributions of a species.
We derived the specific PCEs essential to the conservation of Lepidium papilliferum based on the known biological needs of the species. We consider the physical or biological features essential to the conservation of L. papilliferum to be those PCEs laid out in the appropriate quantity and spatial arrangement to provide for the conservation of the species. All areas proposed as critical habitat for L. papilliferum are currently occupied, were occupied at the time of listing, and are within the species' historical geographic range.
With rare exception, Lepidium papilliferum is known only to occur in slickspot habitat microsites scattered within the greater semiarid sagebrush-steppe ecosystem of southwestern Idaho. The restricted distribution of L. papilliferum is likely due to its adaptation to the specific conditions within these slickspot habitats. Slickspots are distinguished from the surrounding sagebrush habitat as having the following characteristics: microsites where water pools when rain falls (Fisher et al. 1996, pp
tered within the greater semiarid sagebrush-steppe ecosystem of southwestern Idaho. The restricted distribution of L. papilliferum is likely due to its adaptation to the specific conditions within these slickspot habitats. Slickspots are distinguished from the surrounding sagebrush habitat as having the following characteristics: microsites where water pools when rain falls (Fisher et al. 1996, pp. 2, 4); sparse native vegetation; distinct soil layers with a columnar or prismatic structure, higher alkalinity and clay content, and natric (sodic, high sodium) properties (Fisher et al. 1996, pp. 15-16; Meyer and Allen 2005, pp. 3-5, 8; Palazzo et al. 2008, p. 378); and reduced levels of organic matter and nutrients due to lower biomass production (Meyer and Quinney 1993, pp. 3, 6; Fisher et al. 1996, p. 4). Although the low permeability of slickspots appears to help hold moisture (Moseley 1994, p. 8), once the thin crust dries out, the survival of L. papilliferum seedlings depends on the ability of the plant to extend the taproot into the argillic horizon (soil layer with high clay content) to extract moisture from the deeper natric zone (Fisher et al. 1996, p. 13).
Ecologically functional slickspots have the following three primary layers: the surface silt layer, the middle restrictive layer, and an underlying moist clay layer. Although slickspots can appear homogeneous on the surface, the actual depth of the silt and restrictive layer can vary throughout the slickspot (Meyer and Allen 2005, Tables 9, 10, and 11). The top two layers (surface silt and restrictive) of slickspots are normally very thin; the surface silt layer varies in thickness from a few mm to 3 cm (0.1 to 1.2 in) in slickspots known to support Lepidium papilliferum, and the restrictive layer varies in thickness from 1 to 3 cm (0.4 to 1.2 in) (Meyer and Allen 2005, p. 3). Fisher et al. (1995, p. 4) describe the smooth surface layer of slickspots as crustlike, with prominent vesicular pores
of slickspots are normally very thin; the surface silt layer varies in thickness from a few mm to 3 cm (0.1 to 1.2 in) in slickspots known to support Lepidium papilliferum, and the restrictive layer varies in thickness from 1 to 3 cm (0.4 to 1.2 in) (Meyer and Allen 2005, p. 3). Fisher et al. (1995, p. 4) describe the smooth surface layer of slickspots as crustlike, with prominent vesicular pores. Below the surface layer, the soil clay content increases abruptly and creates a strongly-structured, finely-textured boundary (horizon) formed by the concentration of silicate clay materials, known as an argillic horizon. Slickspot soil profiles are distinctive and distinguished from the surrounding soil matrix by very thin surface layers that form prominently vesicular crusts, natric-like argillic horizons that occur just below the soil surface, and by increasingly saline and sodic conditions with depth (Fisher et al. 1995, pp. 11, 16). Disturbances that alter the physical properties of slickspot soil layers, such as deep disturbance and the addition of organic matter, may lead to destruction and permanent loss of slickspots. Slickspot soils are especially susceptible to mechanical disturbances when wet (Rengasmy et al. 1984, p. 63; Seronko 2004, in litt. ). Such disturbances disrupt the soil layers important to L. papilliferum seed germination and seedling growth, and alter hydrological function.
The biological soil crust, also known as a microbiotic crust or cryptogamic crust, is another component of quality habitat for Lepidium papilliferum. Such crusts are commonly found in semiarid et al. 2006, pp. 174, 176). These crusts are sensitive to disturbances that disrupt crust integrity, such as compression due to livestock trampling or off-road vehicle (ORV) use, and are also vulnerable to damage by fire. Recovery from disturbance is possible but occurs very slowly (Johnston 1997, pp. 10-11)
t of quality habitat for Lepidium papilliferum. Such crusts are commonly found in semiarid et al. 2006, pp. 174, 176). These crusts are sensitive to disturbances that disrupt crust integrity, such as compression due to livestock trampling or off-road vehicle (ORV) use, and are also vulnerable to damage by fire. Recovery from disturbance is possible but occurs very slowly (Johnston 1997, pp. 10-11).
The native, semiarid sagebrush-steppe habitat of southwestern Idaho where Lepidium papilliferum is found can be divided into two plant associations, each dominated by the shrub Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush): (1) A. tridentata ssp. wyomingensis - Achnatherum thurberianum (formerly Stipa thurberiana ) (Thurber's needlegrass); and (2) A. tridentata ssp. wyomingensis - Agropyron spicatum (bluebunch wheatgrass) habitat types. The perennial bunchgrasses Poa secunda (Sandberg's bluegrass) and Sitanion hysrix (bottlebrush squirreltail) are commonly found in the understory of these habitats, and the species Artemisia tridentata ssp. tridentata (basin big sagebrush), Chrysothamnus nauseosus (grey rabbitbrush), Chrysothamnus viridiflorus (green rabbitbrush), Eriogonum strictum (strict buckwheat), Purshia tridentata (bitterbrush), and Tetradymium glabrata (little-leafed horsebrush) form a lesser component of the shrub community. Under relatively undisturbed conditions, the understory is populated by a diversity of perennial bunchgrasses and forbs, including species such as Achnatherum (formerly Oryzopsis ) hymenoides (Indian ricegrass), Achillea millefolium (common yarrow), Phacelia heterophylla (varileaf phacelia), Astragalus purshii (Pursh's milkvetch), Phlox longifolia (longleaf phlox), and Aristida purpurea var. longiseta (purple threeawn).
Lepidium papilliferum is primarily an outcrossing species requiring pollen from separate plants for more successful fruit production; it exhibits low seed set in the absence of insect pollinators (Robertson 2003, p. 5; Robertson and Klemash 2003, p
arileaf phacelia), Astragalus purshii (Pursh's milkvetch), Phlox longifolia (longleaf phlox), and Aristida purpurea var. longiseta (purple threeawn).
Lepidium papilliferum is primarily an outcrossing species requiring pollen from separate plants for more successful fruit production; it exhibits low seed set in the absence of insect pollinators (Robertson 2003, p. 5; Robertson and Klemash 2003, p. 339; Robertson and Ulappa 2004, p. 1707; Billinge and Robertson 2008, pp. 1005-1006). Lepidium papilliferum is capable of self-pollinating, however, with a selfing rate (rate of self-pollination) of 12 to 18 percent (Billinge 2006, p. 40; Robertson et al. 2006a, p. 40).
Known Lepidium papilliferum insect pollinators include several families of bees (Hymenoptera), including Apidae, Halictidae, Sphecidae, and Vespidae; beetles (Coleoptera), including Dermestidae, Meloidae, and Melyridae; flies (Diptera), including Bombyliidae, Syrphidae, and Tachinidae; and others (Robertson and Klemash 2003, p. 336; Robertson et al. 2006b, p. 6). Seed set does not appear to be limited by the abundance of pollinators (Robertson et al. 2004, p. 14). However, studies have shown a strong positive correlation between insect diversity and the number of L. papilliferum flowering at a site (Robertson and Hannon 2003, p. 8). Measurement of fruit set per visit revealed considerable variability in the effectiveness of pollination by different types of insects. Since L. papilliferum has a wide array of pollinators, general pollinator management practices for conservation of pollinators should be practiced at sites designated as critical habitat. These practices include “a diversity of native plants whose blooming times overlap to provide flowers for foraging throughout the seasons; nesting and egg-laying sites, with appropriate nesting materials; sheltered, undisturbed places for hibernation and overwintering; and a landscape free of poisonous chemicals” (Shepherd et al. 2003, pp. 49-50)
practiced at sites designated as critical habitat. These practices include “a diversity of native plants whose blooming times overlap to provide flowers for foraging throughout the seasons; nesting and egg-laying sites, with appropriate nesting materials; sheltered, undisturbed places for hibernation and overwintering; and a landscape free of poisonous chemicals” (Shepherd et al. 2003, pp. 49-50). An intact native sagebrush community, as opposed to a monoculture of nonnative annual grasslands such as Bromus tectorum, is more likely to support a wider array of pollinators. Many pollinators depend on native plants and may be unable to access resources from introduced species; many bees, for example, not only require large numbers of flowers to provide nectar and pollen, but also need a variety of flowering plants to sustain them throughout the growing season (Kearns and Inouye 1997, p. 298).
To ensure that sufficient habitat and a diversity of native flowering plants are available to support the pollinator community required for the viability of Lepidium papilliferum populations, we determined that each EO should be surrounded by a minimum pollinator-use area extending 250 m (820 ft) from the periphery. We chose this extent as a reasonable estimate of the area needed to sustain an active pollinator community for L. papilliferum (see Methods, above). The areas proposed as critical habitat will ensure maintenance and continuity of foraging habitats for insect pollinators adjacent to occupied slickspots, which helps to increase seed viability and production and is essential for maintaining genetic diversity in the species over the long term. Additionally, the provision of sufficient native sagebrush-steppe habitat protects L. papilliferum from wildfire, nonnative plant invasions, and colonization by harvester ants, and it helps to maintain local ecosystem characteristics within the larger landscape, which are crucial for protecting the species and its seed bank. The seed bank is an essential feature of L
he species over the long term. Additionally, the provision of sufficient native sagebrush-steppe habitat protects L. papilliferum from wildfire, nonnative plant invasions, and colonization by harvester ants, and it helps to maintain local ecosystem characteristics within the larger landscape, which are crucial for protecting the species and its seed bank. The seed bank is an essential feature of L. papilliferum's biology because it provides the species with resilience in the face of stochastic impacts and variation in environmental conditions.
All areas designated as critical habitat for Lepidium papilliferum were occupied at the time of listing, are within the species' historical geographic range, and provide sufficient PCEs to support at least one life-history function. Based on the above needs and our current knowledge of the life history, biology, and ecology of the species and the habitat requirements for sustaining the essential life history functions of the species, we have determined that Lepidium papilliferum's PCEs include:
(1) Ecologically-functional microsites or “slickspots” that are characterized by:
(a) A high sodium and clay content, and a three-layer soil horizonation sequence, which allows for successful seed germination, seedling growth, and maintenance of the seed bank. The surface horizon consists of a thin, silty, vesicular, pored (small cavity) layer that forms a physical crust (the silt layer). The subsoil horizon is a restrictive clay layer with an abruptic (referring to an abrupt change in texture) boundary with the surface layer, that is natric or natric-like in properties (a type of argillic (clay-based) horizon with distinct structural and chemical features) (the restrictive layer). The second argillic subsoil layer (that is less distinct than the upper argillic horizon) retains moisture through part of the year (the moist clay layer); and
uptic (referring to an abrupt change in texture) boundary with the surface layer, that is natric or natric-like in properties (a type of argillic (clay-based) horizon with distinct structural and chemical features) (the restrictive layer). The second argillic subsoil layer (that is less distinct than the upper argillic horizon) retains moisture through part of the year (the moist clay layer); and
(b) Sparse vegetation with low to moderate introduced, invasive, nonnative plant species cover.
(2) Relatively-intact, native Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush) vegetation assemblages, represented by native bunchgrasses, shrubs, and forbs, within 250 m (820 ft) of Lepidium papilliferum element occurrences to protect slickspots and Lepidium papilliferum from disturbance L. papilliferum's pollinators.
(3) A diversity of native plants whose blooming times overlap to provide pollinator species with sufficient flowers for foraging throughout the seasons and to provide nesting and egg-laying sites; appropriate nesting materials; and sheltered, undisturbed places for hibernation and overwintering of pollinator species. In order for genetic exchange of Lepidium papilliferum to occur, pollinators must be able to move freely between slickspots. Alternative pollen and nectar sources (other plant species within the surrounding sagebrush vegetation) are needed to support pollinators during times when Lepidium papilliferum is not flowering, when distances between slickspots are large, and in years when L. papilliferum is not a prolific flowerer.
e of Lepidium papilliferum to occur, pollinators must be able to move freely between slickspots. Alternative pollen and nectar sources (other plant species within the surrounding sagebrush vegetation) are needed to support pollinators during times when Lepidium papilliferum is not flowering, when distances between slickspots are large, and in years when L. papilliferum is not a prolific flowerer.
(4) Sufficient pollinators for successful fruit and seed production, particularly pollinator species of the sphecid and vespid wasp families, species of the bombyliid and tachnid fly families, honeybees, and halictid bee species, most of which are solitary insects that nest outside of slickspots in the surrounding sagebrush-steppe vegetation, both in the ground and within the vegetation.
The space for individual and population growth is provided by PCEs 1, 2, and 3; the need for food, water, air, light, minerals, or other physiological requirements is provided by PCEs 1 and 2; the need for cover and shelter is met by PCEs 1 and 2; sites for reproduction, germination, and seed dispersal are provided by PCEs 1, 2, 3, and 4; and habitat free from disturbance is met by PCE 2. All of the above described PCEs do not have to occur simultaneously within a unit for the unit to constitute critical habitat for Lepidium papilliferum. All units and subunits proposed in this rule as critical habitat contain at least one of the PCEs to provide for one or more of the life-history functions of L. papilliferum.
Special Management Considerations or Protection
Within the geographical area occupied by the species at the time it was listed, section 3(5)(A) of the Act defines critical habitat as those specific areas on which are found those physical or biological features essential to the conservation of the species and that may require special management considerations or protection
s of L. papilliferum.
Special Management Considerations or Protection
Within the geographical area occupied by the species at the time it was listed, section 3(5)(A) of the Act defines critical habitat as those specific areas on which are found those physical or biological features essential to the conservation of the species and that may require special management considerations or protection. Accordingly, when designating critical habitat, we assess whether the PCEs within the areas occupied at the time of listing may require special management consideration or protections.
A detailed discussion of the threats affecting the physical and biological features essential to the conservation of Lepidium papilliferum, and that may require special management consideration or protection, can be found in the final listing rule published in the Federal Register on October 8, 2009 (74 FR 52014). The primary threats to the PCEs for L. papilliferum include the following direct and indirect effects: The current wildfire regime ( i.e., increasing frequency, size, and duration), invasive, nonnative plant species ( e.g., Bromus tectorum ), and habitat loss and fragmentation due to agricultural and urban development. One of the indirect threats experienced by L. papilliferum is the negative impact on insect pollinators caused by conversion and fragmentation of native habitats due to invasive, nonnative plant species and various forms of development. Another indirect threat is the potential increase in seed predation by harvester ants resulting from the conversion of sagebrush-steppe to nonnative annual grasses such as B. tectorum. Livestock pose a threat to L. papilliferum, primarily through mechanical damage to individual plants and slickspot habitats; however, current livestock management conditions and associated conservation measures address this potential threat such that it does not pose a significant risk to the viability of the species as a whole
n of sagebrush-steppe to nonnative annual grasses such as B. tectorum. Livestock pose a threat to L. papilliferum, primarily through mechanical damage to individual plants and slickspot habitats; however, current livestock management conditions and associated conservation measures address this potential threat such that it does not pose a significant risk to the viability of the species as a whole. Other, less significant factors that have the potential to impact the species include the effects from rangeland revegetation projects, wildfire management practices, recreation, and military use.
Current Wildfire Regime
The current wildfire regime and invasive, nonnative plant species were cited in the final listing rule as the primary cause for the decline of Lepidium papilliferum. The invasion of nonnative plant species, particularly annual grasses such as Bromus tectorum and Taeniatherum caput-medusae (medusahead), has contributed to increasing the amount and continuity of fine fuels across the landscape, and as a result, the wildfire frequency interval has been shortened from between 60 to 110 years historically to less than 5 years in many areas of the sagebrush-steppe ecosystem at present (Wright and Bailey 1982, p. 158; Billings 1990, pp. 307-308; Whisenant 1990, p. 4; USGS 1999, in litt., pp. 1-9; West and Young 2000, p. 262). These wildfires tend to be larger and burn more uniformly than those that occurred historically, resulting in fewer patches of unburned vegetation, which can affect the post-fire recovery of native sagebrush-steppe vegetation (Whisenant 1990, p. 4). The result of this altered wildfire regime has been the conversion of vast areas of the former sagebrush-steppe ecosystem to nonnative annual grasslands (USGS 1999, in litt., pp. 1-9). Frequent wildfires can also promote soil erosion and sedimentation (Bunting et al. 2003, p. 82) in arid environments such as the sagebrush-steppe ecosystem. Increased sedimentation can result in a silt layer that is too thick for optimal L
ed wildfire regime has been the conversion of vast areas of the former sagebrush-steppe ecosystem to nonnative annual grasslands (USGS 1999, in litt., pp. 1-9). Frequent wildfires can also promote soil erosion and sedimentation (Bunting et al. 2003, p. 82) in arid environments such as the sagebrush-steppe ecosystem. Increased sedimentation can result in a silt layer that is too thick for optimal L. papilliferum germination (Meyer and Allen 2005, pp. 6-7).
I. Several researchers have noted signs of increased habitat degradation for Lepidium papilliferum, most notably in terms of exotic species cover and wildfire frequency ( e.g., Moseley 1994, p. 23; Menke and Kaye 2006b, p. 19; Colket 2008, pp. 33-34), but only recently have analyses demonstrated a statistically significant, negative relationship between the degradation of habitat quality, both within slickspot microsites and in the surrounding sagebrush-steppe matrix, and the abundance of L. papilliferum. Sullivan and Nations (2009, pp. 114-118, 137) found a consistent, statistically significant, negative correlation between wildfire and the abundance of L. papilliferum across its range. Their analysis of 5 years of Habitat Integrity and Population (HIP) monitoring data indicated that L. papilliferum “abundance was lower within those slickspot [sic] that had previously burned” (Sullivan and Nations 2009, p. 137), and the relationship between L. papilliferum abundance and fire is reported as “relatively large and statistically significant,” regardless of the age of the fire or the number of past fires (Sullivan and Nations 2009, p. 118). The nature of this relationship was not affected by the number of fires that may have occurred in the past; whether only one fire had occurred or several, the association with decreased abundance of L. papilliferum was similar (Sullivan and Nations 2009, p. 118)
large and statistically significant,” regardless of the age of the fire or the number of past fires (Sullivan and Nations 2009, p. 118). The nature of this relationship was not affected by the number of fires that may have occurred in the past; whether only one fire had occurred or several, the association with decreased abundance of L. papilliferum was similar (Sullivan and Nations 2009, p. 118).
Special management to protect the proposed critical habitat areas and the features essential to the conservation of Lepidium papilliferum from the effects of the current wildfire regime may include preventing or restricting the establishment of invasive, nonnative plant species, post-wildfire restoration with native plant species, and reducing the likelihood of wildfires affecting the nearby plant community components. Local fire agencies can achieve the latter
Invasive, Nonnative Plant Species
The conversion of sagebrush-steppe habitat to nonnative annual grasslands over the past several decades has reduced or degraded suitable habitat for Lepidium papilliferum, in addition to fragmenting and isolating extant occupied areas. There are two primary ways for invasive, nonnative plants to become established in L. papilliferum habitats, through natural spreading (unseeded) or revegetation projects (seeded). The rates at which nonnative unseeded species are spreading, oftentimes into relatively intact habitats, is of major concern to natural resource managers. Invasive, nonnative plants can alter various attributes of ecosystems including geomorphology, wildfire regime, hydrology, microclimate, nutrient cycle, and productivity (for a summary see Dukes and Mooney 2003, entire). Additionally, these invasive, nonnative plants can negatively affect native plants, including rare plants like L
intact habitats, is of major concern to natural resource managers. Invasive, nonnative plants can alter various attributes of ecosystems including geomorphology, wildfire regime, hydrology, microclimate, nutrient cycle, and productivity (for a summary see Dukes and Mooney 2003, entire). Additionally, these invasive, nonnative plants can negatively affect native plants, including rare plants like L. papilliferum, through competitive exclusion, niche displacement, hybridization, and competition for pollinators; examples of these negative effects are widespread among different taxa, locations, and ecosystems (D'Antonio and Vitousek 1992, pp. 63-87; Olson 1999, p. 5; Mooney and Cleland 2001, p. 1). Recent analyses have revealed a significant, negative association between the presence of weedy species and the abundance or density of L. papilliferum, to the point that L. papilliferum may be excluded from slickspots (Sullivan and Nations 2009, pp. 109-112). Although the specific mechanisms are not well understood, some of these plants, such as Agropyrum cristatum (crested wheatgrass) and Bromus tectorum, are strong competitors in this arid environment for such limited resources as moisture, which tends to be concentrated in slickspots (Pyke and Archer 1991, p. 4; Moseley 1994, p. 8; Lesica and DeLuca 1998, p. 4), at least in the subsurface soils (Fisher et al. 1996, pp. 13-16).
Special management to protect the features essential to the conservation of Lepidium papilliferum in the areas proposed as critical habitat from the effects of invasive, nonnative unseeded plant species may include the following: (1) protecting remnant blocks of native vegetation, (2) educating the public about invasive, nonnative species, (3) supporting research and funding for nonnative plant species control, (4) preventing or restricting the establishment of nonnative plant species, (5) washing vehicles prior to any travel into areas containing L. papilliferum, (6) quarantining livestock prior to entering allotments containing L
cting remnant blocks of native vegetation, (2) educating the public about invasive, nonnative species, (3) supporting research and funding for nonnative plant species control, (4) preventing or restricting the establishment of nonnative plant species, (5) washing vehicles prior to any travel into areas containing L. papilliferum, (6) quarantining livestock prior to entering allotments containing L. papilliferum, and (7) reducing the likelihood of wildfires.
Livestock Use
The most visible effect to Lepidium papilliferum and its habitat from livestock use is through trampling impacts. Livestock trampling can affect the fragile soil layers of slickspots (Colket 2005, p. 34; Meyer et al. 2005, pp. 21-22; Seronko 2004, in litt. ). Trampling when slickspots are dry can lead to mechanical damage to the slickspot soil crust, potentially resulting in invasion of nonnative plants into the slickspots and altering the hydrologic function of slickspots, but is hypothesized to be less of an impact to L. papilliferum habitats than trampling of wet slickspot soils. Livestock trampling of water-saturated slickspot soils that breaks through the restrictive layer (referred to as “penetrating trampling” (State of Idaho et al. 2006, p. 9)) has the potential to alter the soil structure and the functionality of slickspots (Rengasamy et al. 1984, p. 63; Seronko 2004, in litt. ). Penetrating trampling that occurs when slickspots are wet also has the potential to affect the seed bank for L. papilliferum by pushing the seeds below a depth where they can germinate ( i.e., below 3 cm (1.5 in.)) (Meyer and Allen 2005, pp. 9-10; Meyer et al. 2006, pp. 891, 901-902).
There are also indirect effects from livestock use that have impacted the sagebrush-steppe ecosystem. Livestock use has been suggested as a contributing factor to the spread of invasive, nonnative plant species (Frost and Launchbaugh 2003, pp. 43-45)
e seeds below a depth where they can germinate ( i.e., below 3 cm (1.5 in.)) (Meyer and Allen 2005, pp. 9-10; Meyer et al. 2006, pp. 891, 901-902).
There are also indirect effects from livestock use that have impacted the sagebrush-steppe ecosystem. Livestock use has been suggested as a contributing factor to the spread of invasive, nonnative plant species (Frost and Launchbaugh 2003, pp. 43-45). The spread of Bromus tectorum on the Snake River Plain in particular has been attributed to several causes, including the past practice of heavy, unmanaged livestock use in the late 1800s (Mack 1981, pp. 145-165). Today, invasive, nonnative annual plants such as B. tectorum are so widespread that they have been documented spreading into areas that have not been disturbed (Tisdale et al. 1965, pp. 349, 351). Therefore, the absence of livestock use is no longer sufficient, by itself, to protect the landscape from invasive, nonnative species (Frost and Launchbaugh 2003, p. 44).
With careful management, livestock grazing may be used as a tool to select for certain native species, or even to control B. tectorum (Frost and Launchbaugh 2003, p. 43). For example, under the revised Juniper Butte Range Integrated Natural Resources Management Plan (INRMP), the U.S. Air Force will continue to use livestock throughout the majority of the Juniper Butte Range to reduce the amount of standing grass biomass to in turn reduce wildfire risk (U.S. Air Force 2004, pp. 6-37 through 6-39). However, this requires intensive management and timing that is not typically feasible over large areas.
Research designed to specifically examine the relationship between livestock use and Lepidium papilliferum is currently being conducted by the University of Idaho and the State of Idaho in cooperation with the Service (State of Idaho et al. 2006, p. 119)
Air Force 2004, pp. 6-37 through 6-39). However, this requires intensive management and timing that is not typically feasible over large areas.
Research designed to specifically examine the relationship between livestock use and Lepidium papilliferum is currently being conducted by the University of Idaho and the State of Idaho in cooperation with the Service (State of Idaho et al. 2006, p. 119).
Special management to protect the features essential to the conservation of Lepidium papilliferum from the effects of livestock use in the areas proposed as critical habitat may include conservation measures and actions to minimize the effects of livestock use on these lands. Existing conservation plans contain numerous measures to avoid, mitigate, and monitor the effects of livestock use on L. papilliferum. Livestock-grazing conservation measures implemented through the State of Idaho Candidate Conservation Agreement (CCA) and the U.S. Air Force INRMP apply to all Federal and State-managed lands within the occupied range of L. papilliferum (approximately 95 percent of the total occupied area). Existing conservation measures include prescribing a minimum distance for the placement of salt and water troughs, identifying livestock use restrictions to reduce trampling of slickspots during wet periods, constructing fences, or potentially modifying current livestock use. We recognize the potential for negative impacts to L. papilliferum populations and slickspots that may result from seasonal, localized trampling events. However, under current management conditions, we do not consider livestock use to pose a significant threat to L. papilliferum. We encourage the continued implementation of conservation measures and associated monitoring to ensure potential impacts of livestock trampling to L. papilliferum are avoided or minimized
opulations and slickspots that may result from seasonal, localized trampling events. However, under current management conditions, we do not consider livestock use to pose a significant threat to L. papilliferum. We encourage the continued implementation of conservation measures and associated monitoring to ensure potential impacts of livestock trampling to L. papilliferum are avoided or minimized.
Residential and Agricultural Development
Past residential and agricultural development was responsible for five documented extirpations and four probable extirpations of Lepidium papilliferum (Colket et al. 2006, p. 4). The long-term viability of L. papilliferum on private land on the Snake River Plain and adjacent Boise L. papilliferum and slickspot habitat through habitat conversion, increased nonnative plant invasions, increased ORV use, increased wildfire, changes to insect populations, and increased fragmentation. Utility lines such as power and gas lines, as well as roads, also fragment L. papilliferum occupied areas and act as corridors for nonnative plant invasions.
Special management to protect the features essential to the conservation of Lepidium papilliferum from the effects of residential and agricultural development in the areas proposed may include creating managed plant reserves and open spaces; limiting disturbances to and within suitable habitats; increasing compliance inspections with permit holders; requiring project fencing with adjacent construction activities; disallowing new roads; and evaluating the need for and conducting restoration or revegetation of native plants in open spaces, plant preserves, or disturbed areas, such as cuts for powerlines.
The designation of critical habitat does not imply that lands outside of critical habitat do not play an important role in the conservation of Lepidium papilliferum
g with adjacent construction activities; disallowing new roads; and evaluating the need for and conducting restoration or revegetation of native plants in open spaces, plant preserves, or disturbed areas, such as cuts for powerlines.
The designation of critical habitat does not imply that lands outside of critical habitat do not play an important role in the conservation of Lepidium papilliferum. Activities with a Federal nexus that may affect those areas outside of critical habitat, such as development, agricultural, or road construction activities, are still subject to review under section 7 of the Act if they may affect L. papilliferum. The prohibitions of section 9 of the Act include the import or export of listed species, and the removal to possession or malicious damage or destruction of a species under Federal jurisdiction (16 U.S.C. 1538(a)(2)).
Criteria Used To Identify Critical Habitat
As required by section 4(b)(2) of the Act, we used the best scientific data available in determining those specific areas within the geographical area occupied at the time of listing that contain the features essential to the conservation of Lepidium papilliferum and that may require special management considerations or protection. Our proposed designation of critical habitat for L. papilliferum is based on the information and procedures detailed in the Methods section, above. As described, we are proposing to designate critical habitat within the three physiographic regions where the species was known to occur at the time of listing (October 8, 2009), the Boise Foothills, the Snake River Plain, and the Owyhee Plateau. The areas we are proposing to designate as critical habitat were all occupied at the time of listing, and provide physical and biological features essential for the conservation of L. papilliferum that may require special management considerations or protection. All proposed areas provide one or more of the PCEs for life history function
se Foothills, the Snake River Plain, and the Owyhee Plateau. The areas we are proposing to designate as critical habitat were all occupied at the time of listing, and provide physical and biological features essential for the conservation of L. papilliferum that may require special management considerations or protection. All proposed areas provide one or more of the PCEs for life history function. We do not propose to designate areas outside the geographical area presently occupied by the species.
We included all Lepidium papilliferum EOs with INHP rankings of B, BC, and C in the proposed critical habitat. We conclude that areas with these rankings provide the physical and biological features essential to the conservation of the species, as they are most likely to provide for viable populations of L. papilliferum that will contribute to the conservation and recovery of the species, and each provides one or more of the PCEs as defined in this proposed rule. EOs ranked as B have one or more of the following features: More than 399 individuals, low nonnative plant species cover, predominantly unburned, few anthropogenic disturbances, and a surrounding landscape that is only minimally or partially fragmented within a distance of 1 km (0.6 mi). EOs ranked C have one or more of the following features: More than 50 individuals; low to moderate nonnative plant species cover; only partially burned; few to moderate anthropogenic disturbances; and a surrounding landscape within 1 km (0.6 mi) that is not predominantly fragmented by development, nonnative annual grasslands, or nonnative seeding projects. For the purposes of the proposed critical habitat analyses, we categorized areas containing B- or BC-ranked EOs (intermediate between B-rank and C-rank, see Colket et al. 2006, p. 5) as having high conservation value for the slickspot peppergrass, while areas containing C-ranked EOs were categorized as having medium conservation value for the species
nual grasslands, or nonnative seeding projects. For the purposes of the proposed critical habitat analyses, we categorized areas containing B- or BC-ranked EOs (intermediate between B-rank and C-rank, see Colket et al. 2006, p. 5) as having high conservation value for the slickspot peppergrass, while areas containing C-ranked EOs were categorized as having medium conservation value for the species. Because data on condition, landscape context, and size are used to calculate the EO rankings, it is important to keep in mind that while some EOs included as critical habitat have lower habitat quality than others, their higher ranking may reflect their larger size. Based on the ranking definitions detailed above, EOs ranked as B, BC, and C are considered to contain some or all of the PCEs essential to the conservation of Lepidium papilliferum. We considered those EOs ranked C or higher to provide the PCEs for L. papilliferum in the quantity and spatial arrangement essential to the conservation of the species, and determined that these EOs are collectively sufficient to achieve the conservation and recovery of the species.
We did not include sites ranked D or lower in the proposed designation. D-ranked sites have 50 or fewer individuals of Lepidium papilliferum, and the quality of the habitat is poor. Few components of the native plant community remain, introduced plant species cover is high, and the slickspots themselves have high invasive, nonnative plant cover or have been subject to livestock disturbance. Few or several moderately severe anthropogenic disturbances are evident at such sites, and each site has been predominantly to completely burned (Colket et al. 2006, p. 4). Portions of these sites may have been drill-seeded (seeded using a specialized attachment on a tractor to mechanically plant seeds), which alters the slickspot soil layers
nt cover or have been subject to livestock disturbance. Few or several moderately severe anthropogenic disturbances are evident at such sites, and each site has been predominantly to completely burned (Colket et al. 2006, p. 4). Portions of these sites may have been drill-seeded (seeded using a specialized attachment on a tractor to mechanically plant seeds), which alters the slickspot soil layers. The landscape around such sites is moderately to completely fragmented by agricultural lands, residential or commercial development, introduced annual grasslands, or drill-seeding projects (Colket et al. 2006, p. 4). Due to the poor condition of the habitat around D-ranked sites, the low viability of the small L. papilliferum populations remaining at such sites, and the fragmented nature of the surrounding landscape, we determined that EOs ranked D or lower do not provide the PCEs in sufficient quantity or spatial arrangement to be essential to the conservation of the species, and are therefore not expected to make any meaningful contribution to the recovery of the species. Based on our evaluation of EOs ranked C or higher, we did not consider sites ranked D or lower to be necessary to achieve the conservation of the species. Therefore, we did not include EOs ranked D or lower in the proposed designation.
Based on this analysis, we are proposing to designate four units as critical habitat for Lepidium papilliferum: The Ada County Unit, the Elmore County Unit, the Owyhee County Unit, and the Payette County Unit. Two of these units are further divided into subunits; the Ada County Unit has four subunits and the Elmore County Unit has three subunits. Subunits are used for ease of mapping
esignation.
Based on this analysis, we are proposing to designate four units as critical habitat for Lepidium papilliferum: The Ada County Unit, the Elmore County Unit, the Owyhee County Unit, and the Payette County Unit. Two of these units are further divided into subunits; the Ada County Unit has four subunits and the Elmore County Unit has three subunits. Subunits are used for ease of mapping. There are 17 EOs within the Ada County Unit, 12 EOs within the Elmore County Unit, 11 EOs within the Owyhee County Unit, and 3 EOs within the Payette County Unit, for a total of 43 EOs, ranked B, BC, or C, included in this
When determining proposed critical habitat boundaries within this proposed rule, we made every effort to avoid including developed areas such as lands covered by buildings, pavement, and other structures because such lands lack PCEs for Lepidium papilliferum. 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 require section 7 consultation with respect to critical habitat, nor would it trigger the requirement of no adverse modification, unless the specific action would affect the PCEs in the adjacent critical habitat.
Proposed Critical Habitat Designation
We are proposing four units as critical habitat for Lepidium papilliferum. The critical habitat areas we describe below constitute our current best assessment of areas that meet the definition of critical habitat for L. papilliferum. The four areas we propose as critical habitat are: (1) The Ada County Unit, (2) the Elmore County Unit, (3) the Owyhee County Unit, and (4) the Payette County Unit
We are proposing four units as critical habitat for Lepidium papilliferum. The critical habitat areas we describe below constitute our current best assessment of areas that meet the definition of critical habitat for L. papilliferum. The four areas we propose as critical habitat are: (1) The Ada County Unit, (2) the Elmore County Unit, (3) the Owyhee County Unit, and (4) the Payette County Unit. All units were occupied at the time of listing and are currently occupied. The approximate areas of each proposed critical habitat unit and associated subunits, if any, are shown in Table 1.
Table 1—Proposed Critical Habitat Units and Area (Hectares (Acres)) by Land Ownership for Lepidium Papilliferum [Area estimates reflect all land within proposed critical habitat unit boundaries] Unit or subunit Federal State Municipal (county) Private Total Unit 1—Payette County 257 ha (635 ac) 0 ha (0 ac) 0 ha (0 ac) 16 ha (40 ac) 273 ha (675 ac) Unit 2—Ada County 4,842 ha (11,964 ac) 1,149 ha (2,840 ac) 340 ha (840 ac) 667 ha (1,648 ac) 6,998 ha (17,292 ac) 2a 644 ha (1,592 ac) 0 ha (0 ac) 340 ha (840 ac) 291 ha (719 ac) 1,275 ha (3,151 ac) 2b 2,676 ha (6,613 ac) 98 ha (241 ac) 0 ha (0 ac) 32 ha (80 ac) 2,806 ha (6,934 ac) 2c 512 ha (1,265 ac) 98 ha (242 ac) 0 ha (0 ac) 311 ha (768 ac) 921 ha (2,275 ac) 2d 1,009 ha (2,494 ac) 954 ha (2,357 ac) 0 ha (0 ac) 33 ha (81 ac) 1,996 ha (4,932 ac) Unit 3—Elmore County 3,483 ha (8,606 ac) 97 ha (239 ac) 0 ha (0 ac) 418 ha (1,034 ac) 3,998 ha (9,879 ac) 3a 696 ha (1,721 ac) 0 ha (0 ac) 0 ha (0 ac) 241 ha (595 ac) 937 ha (2,316 ac) 3b 656 ha (1,621 ac) 97 ha (239 ac) 0 ha (0 ac) 49 ha (120 ac) 801 ha (1,980 ac) 3c 2,130 ha (5,264 ac) 0 ha (0 ac) 0 ha (0 ac) 129 ha (319 ac) 2,259 ha (5,583 ac) Unit 4—Owyhee County 11,505 ha (28,428 ac) 600 ha (1,482 ac) 0 ha (0 ac) 0 ha (0 ac) 12,105 ha (29,910 ac) All Units 20,086 ha (49,633 ac) 1,846 ha (4,561 ac) 340 ha (840 ac) 1,102 ha (2,722 ac) 23,374 ha (57,756 ac) Note: Area sizes may not sum exactly due to rounding
c) 0 ha (0 ac) 49 ha (120 ac) 801 ha (1,980 ac) 3c 2,130 ha (5,264 ac) 0 ha (0 ac) 0 ha (0 ac) 129 ha (319 ac) 2,259 ha (5,583 ac) Unit 4—Owyhee County 11,505 ha (28,428 ac) 600 ha (1,482 ac) 0 ha (0 ac) 0 ha (0 ac) 12,105 ha (29,910 ac) All Units 20,086 ha (49,633 ac) 1,846 ha (4,561 ac) 340 ha (840 ac) 1,102 ha (2,722 ac) 23,374 ha (57,756 ac) Note: Area sizes may not sum exactly due to rounding. We present brief descriptions of all units and their constituent subunits below. Each of these units provide one or more PCEs essential to the conservation of the species. As described above under Criteria Used To Identify Critical Habitat, EOs included within the units were chosen using the EO area ranking system developed by the INHP, which takes into account those physical and biological features that are essential to L. papilliferum ( i.e., slickspots, habitat condition within and surrounding the area, and the conditions of the surrounding landscape features necessary to support pollination and other life-history requirements), and that we have determined may require special management considerations or protection. We are not proposing to designate any areas outside the geographical area occupied by the species at the time of listing as critical habitat.
The PCEs in each of these units may require special management considerations or protection to address threats from wildfire, invasive, nonnative plant species, and activities such as livestock trampling or development that may occur in the area. See the Special Management Considerations or Protection section of this proposed rule for a discussion of the threats to L. papilliferum habitat and potential management considerations. Further details on threats to L. papilliferum are provided in the final listing rule for the species, published in the Federal Register on October 8, 2009 (74 FR 52014).
Unless otherwise cited, information used to develop these descriptions is based on the 2010 INHP Element Occurrence Records (EOR) (INHP 2010, in litt
he threats to L. papilliferum habitat and potential management considerations. Further details on threats to L. papilliferum are provided in the final listing rule for the species, published in the Federal Register on October 8, 2009 (74 FR 52014).
Unless otherwise cited, information used to develop these descriptions is based on the 2010 INHP Element Occurrence Records (EOR) (INHP 2010, in litt. ) and the Element Occurrence review and update for Lepidium papilliferum, which describes how each individual EO was ranked (Colket et al. 2006).
Unit 1: Payette County
The Payette County unit consists of 273 ha (675 ac). The northern boundary of Unit 1 is approximately 7.6 km (4.8 mi) south of New Plymouth, Idaho. Lepidium papilliferum was known to occupy this unit at the time of listing; currently 257 ha (635 ac) are Federally managed by the BLM, and 16 ha (40 ac) are privately owned. This unit is composed of three L. papilliferum EOs: 66, 68, and 70. This unit contains PCEs and is important to the conservation of L. papilliferum because it contains the northernmost occurrences for L. papilliferum and potentially has the highest numbers of individual plants.
The plant community of EO 66 is composed of a fragmented Artemisia tridentata ssp. wyomingensis/Vulpia octoflora (six weeks fescue) community that has had a mosaic burn and was subsequently seeded with Agropyron cristatum (crested wheatgrass). This is a large occurrence, with over 6,700 Lepidium papilliferum individuals observed along HIP transects in 2008. Invasive, nonnative plants, wildfire, and residential development are threats to this EO. Use of ORVs and livestock are potential threats, although an exclosure protects portions of the EO from livestock and ORV use.
The second EO in Unit 1, EO 68, is primarily composed of a Sisymbrium altissimum (tumble mustard)/ Poa secunda community, at times adjacent to small Artemisia tridentata ssp. wyomingensis fragments
ive plants, wildfire, and residential development are threats to this EO. Use of ORVs and livestock are potential threats, although an exclosure protects portions of the EO from livestock and ORV use.
The second EO in Unit 1, EO 68, is primarily composed of a Sisymbrium altissimum (tumble mustard)/ Poa secunda community, at times adjacent to small Artemisia tridentata ssp. wyomingensis fragments. This EO is adjacent to Interstate 84 and is located less than 500 m (1,640 ft) from commercial development. Historically, this EO has had high Lepidium papilliferum abundance; however, the occurrence and surrounding area is very weedy and has burned in the past. Wildfire, invasive, nonnative plants, and livestock use are threats to this occurrence.
The third EO in Unit 1 is EO 70, composed of a contiguous, unburned Artemisia tridentata ssp. wyomingensis / Vulpia octoflora community with low introduced, invasive, nonnative species cover. While a relatively intact landscape surrounds the occurrence, historical wildfire and residential development have occurred within 250 m (820.2 ft) of the EO. The immediate threat to EO 70 is wildfire. In addition, the surrounding area seems to be used as a dumping ground, with trash and garbage evident. Livestock use is also a potential threat.
Unit 2: Ada County
The Ada County unit consists of 6,998 ha (17,292 ac) divided into four subunits: 2a, 2b, 2c, and 2d . Lepidium papilliferum was known to occupy this unit at the time of listing. 4,842 ha (11,964 ac) of this unit are Federally managed by the BLM, 1,149 ha (2,840 ac) are managed by the State of Idaho, 340 ha (840 ac) are managed by Ada County, and 667 ha (1,648 ac) are on private lands. This unit is composed of 17 L. papilliferum EOs split among the four subunits. This unit contains PCEs important to the conservation of L. papilliferum; many of the subunits are large, and contain the most intact areas of sagebrush-steppe habitat that has had little impact from wildfire
ed by the State of Idaho, 340 ha (840 ac) are managed by Ada County, and 667 ha (1,648 ac) are on private lands. This unit is composed of 17 L. papilliferum EOs split among the four subunits. This unit contains PCEs important to the conservation of L. papilliferum; many of the subunits are large, and contain the most intact areas of sagebrush-steppe habitat that has had little impact from wildfire.
Subunit 2a
Subunit 2a contains the city of Eagle, Idaho, and the southern boundary of the unit is approximately 7.2 km (4.5 mi) northwest of Boise, Idaho. It is composed of six EOs: 38, 52, 65, 76, 107, and 108.
Nonnative, annual weedy species dominate the landscape within EO 38, with scattered Purshia tridentata, Artemisia tridentata ssp. wyomingensis, and Ericameria nauseosa (rubber rabbitbrush). This EO is almost completely contained within the Ada County Landfill Complex (Cole 2008, entire) and is located in close proximity to the Idaho Velodrome and Cycling Park and Eagle Sports Complex. In 2008, survey efforts (Cole 2008) found an additional 5,000 L. papilliferum plants, which resulted in a subsequent upgrade to the EO rank. Primary threats to this EO include wildfire (the western portion of this EO burned in 2009 (Ada County 2010, in litt. )); human recreation associated with the construction of authorized and unauthorized trails for mountain biking and hiking (some slickspots have already been impacted); and invasive, nonnative weed invasions and expansions (Cole 2008, pp. 10, 13). Livestock use occurred in the past, but ceased in the area approximately 10 years ago (T. Hutchinson, pers. comm. in Cole 2008, p. 12), and we have no evidence to suggest that livestock use is likely to pose a threat to this EO within the foreseeable future.
EO 52 is composed of a varied plant community, including scattered islands of Purshia tridentata / Artemisia tridentata ssp. wyomingensis / Chrysothamnus viscidiflorus (yellow rabbitbrush) with an understory primarily composed of Bromus tectorum and Poa secunda
2008, p. 12), and we have no evidence to suggest that livestock use is likely to pose a threat to this EO within the foreseeable future.
EO 52 is composed of a varied plant community, including scattered islands of Purshia tridentata / Artemisia tridentata ssp. wyomingensis / Chrysothamnus viscidiflorus (yellow rabbitbrush) with an understory primarily composed of Bromus tectorum and Poa secunda. It is a large EO, with thousands of plants documented. This EO is located near the Eagle/Boise urban area and receives substantial recreational use through hiking, equestrian riding, biking, and ORV use. Residential development occurs within 500 m (1,640 ft) of this subunit. EO 52 is known to be threatened by wildfire, invasive, nonnative plant species, recreation, and development.
EO 65 is composed of an Artemisia tridentata ssp. wyomingensis / Purshia tridentata / Bromus tectorum / Taeniatherum caput-medusae plant community. The Seaman's Gulch Ridge to Rivers trail system runs through and around a portion of this EO south of Seaman's Gulch road (Cole 2008, p. 9). While there is a high diversity of forbs within the EO, the area is generally weedy overall. Biological soil crust cover in the general area is fairly high. Wildfire, invasive, nonnative plant species, and unauthorized recreation trail travel are threats to EO 65.
The vegetative community of EO 76 is Artemisia tridentata ssp. tridentata/Vulpia octoflora with low cover of both native forbs and invasive, nonnative annuals. The surrounding landscape is completely disturbed from a combination of burned areas, residential development, and agricultural lands. However, this is a large occurrence, with approximately 4,800 Lepidium papilliferum individuals observed on the HIP transects in 2008. This EO is threatened by wildfire, invasive, nonnative plant species, livestock use, recreation, and residential and road development.
EO 107 is located on private land. The vegetative community is characterized as degraded Artemisia tridentata ssp
ultural lands. However, this is a large occurrence, with approximately 4,800 Lepidium papilliferum individuals observed on the HIP transects in 2008. This EO is threatened by wildfire, invasive, nonnative plant species, livestock use, recreation, and residential and road development.
EO 107 is located on private land. The vegetative community is characterized as degraded Artemisia tridentata ssp. wyomingensis habitat with an understory of Bromus tectorum and Aristida purpurea var. longiseta. At the time of the survey, there were signs of recent fire in the area. This EO is threatened by wildfire and invasive, nonnative plant species.
EO 108 occurs in an Artemisia tridentata ssp. tridentata / Artemisia tridentata ssp. wyomingensis / Chrysothamnus viscidiflorus-Ericameria nauseosus community with a mix of native and nonnative understory species. The plant community within this EO is in various states of transition given historical disturbance regimes such as fire and use by livestock (URS 2008, p. 6). However, 2007 and 2008 survey data indicate an estimated 1,117 Lepidium papilliferum individuals are located within this EO. Threats to EO 108 include invasive, nonnative plant species, wildfires, livestock use, recreation (including ORV use), and residential and road development.
Subunit 2b
The northern boundary of Subunit 2b is approximately 4.2 km (2.6 mi) south of Kuna, Idaho. Subunit 2b is composed of three EOs: 18, 24, and 25.
EO 18 is a large occurrence composed of Artemisia tridentata / Poa secunda, B. tectorum / Sisymbrium altissimum, and B. tectorum / Bassia prostrata communities. It is located approximately 14.5 km (9 mi) (14.5 km) Bromus tectorum is abundant throughout the area, with P. secunda being the most common bunchgrass. Wildfire destroyed the original sagebrush habitat throughout portions of EO 18 in the mid-1990s. Future wildfires, invasive, nonnative plant species, and recreation are the likely long-term threats facing this EO
rum / Bassia prostrata communities. It is located approximately 14.5 km (9 mi) (14.5 km) Bromus tectorum is abundant throughout the area, with P. secunda being the most common bunchgrass. Wildfire destroyed the original sagebrush habitat throughout portions of EO 18 in the mid-1990s. Future wildfires, invasive, nonnative plant species, and recreation are the likely long-term threats facing this EO.
EO 24 is a large EO; the following vegetative communities are just a few of those found within this EO: Artemisia tridentata ssp. wyomingensis / Bromus tectorum, B. tectorum, and B. tectorum / Agropyron spicatum. It is located approximately 6.4 km (4 mi) south to southwest of Kuna and near the Kuna/Boise urban area. The surrounding area has been highly disturbed by wildfires and roads, with much of the land surrounding Kuna Butte being converted for agricultural use. This EO is known to be threatened by wildfire, invasive, nonnative plant species, and recreation.
The vegetative community of EO 25 is characterized as degraded Artemisia tridentata ssp. wyomingensis habitat. This EO is located near the Kuna/Boise urban area, approximately 6.4 km (4 mi) northeast of Melba. Much of the area has burned and is now predominantly comprised of Bromus tectorum, Sisymbrium altissimum, and Salsola kali with some Poa secunda. EO 25 is threatened by wildfire, invasive, nonnative plant species, and recreation.
Subunit 2c
The northern boundary of Subunit 2c is approximately 8 km (5 mi) south of Boise, Idaho. It is composed of four EOs: 22, 32, 48, and 64.
Information from previous visits describes vegetation within EO 22 as an Artemisia tridentata spp. wyomingensis community with an understory dominated by Bromus tectorum. It is located about 2.4 km (1.5 mi) north of Pleasant Valley. Portions of this EO have burned, with scattered slickspots degraded to varying degrees. Threats to EO 22 include wildfires and their effects on the remaining patches of sagebrush
from previous visits describes vegetation within EO 22 as an Artemisia tridentata spp. wyomingensis community with an understory dominated by Bromus tectorum. It is located about 2.4 km (1.5 mi) north of Pleasant Valley. Portions of this EO have burned, with scattered slickspots degraded to varying degrees. Threats to EO 22 include wildfires and their effects on the remaining patches of sagebrush. Other threats include development of surrounding private land for suburban and commercial purposes.
The vegetative community of EO 32 is composed of an Artemisia tridentata ssp. tridentata / Bromus tectorum and A. tridentata ssp. wyomingensis / Poa secunda community with an understory dominated by invasive, nonnative annual species. Records demonstrate a fair to good number of Lepidium papilliferum plants over a large area. It is located approximately 5.6 km (3.5 mi) southwest of the Boise Airport. This EO is known to be threatened by wildfire, invasive, nonnative plant species, recreation (ORV use), and development. Development is also a potential threat given the proximity of this EO to private lands.
EO 48 is composed of an Artemisia tridentata ssp. wyomingensis/Bromus tectorum / Elymus elymoides plant community. There is a high cover of litter and biological soil crust in slickspots within this EO. The primary threat to EO 48 is from wildfires. Other threats include invasion and expansion of nonnative invasive plant species, livestock use, and recreational use by hunters and ORVs that utilize the adjacent powerline roadway.
Artemisia tridentata ssp. wyomingensis community with Bromus tectorum dominates the understory of EO 64. The EO is located from 50 to 500 m (164 to 1,640 ft) south of the Boise airport and associated development. The slickspots in this EO are in fair condition and have high cover of biological soil crust. Population vigor ranges from moderate to excellent. This EO is threatened by wildfire, invasive, nonnative plant species, and potential development associated with airport activities
story of EO 64. The EO is located from 50 to 500 m (164 to 1,640 ft) south of the Boise airport and associated development. The slickspots in this EO are in fair condition and have high cover of biological soil crust. Population vigor ranges from moderate to excellent. This EO is threatened by wildfire, invasive, nonnative plant species, and potential development associated with airport activities.
Subunit 2d
The northern boundary of subunit 2d is approximately 24.8 km (15.4 mi) southeast of Boise, Idaho. Subunit 2d is composed of four EOs: 27, 72, 77, and 104.
The dominant vegetation of EO 27 consists of Artemisia tridentata ssp. wyomingensis / Poa secunda / Ceratocephala testiculata and A. tridentata ssp. wyomingensis / Bromus tectorum / Lepidium perfoliatum, predominantly the former. It is located approximately 35 km (21 mi) southeast of Boise. Some parts of this EO have burned in the past, although the entire EO is relatively intact and constitutes one of the largest blocks of unburned sagebrush-steppe habitats left on the western Snake River Plain. A portion of this EO includes the Orchard Training Area (OTA), managed by the Idaho Army National Guard, and we are proposing to exempt this area from the designation of critical habitat under section 4(a)(3) of the Act (see Exemptions, below). This EO is known to be threatened by wildfire, invasive, nonnative plant species, and livestock disturbances.
Vegetative communities of EO 72 include the following: Artemisia tridentata ssp. tridentata / Bromus tectorum, Chrysothamnus viscidiflorus / A. tridentata ssp. wyomingensis / Poa secunda, A. tridentata ssp . wyomingensis / P. secunda/B. tectorum / A. tridentata ssp. tridentata, and Agropyron cristatum / P. secunda. This EO is located roughly 23 km (14 mi) south of Boise. Most of the EO has burned at least once in the past couple of decades resulting in a mix of small-to-fairly-large shrub patches intermixed with invasive, nonnative, annual-grassland vegetation
gensis / Poa secunda, A. tridentata ssp . wyomingensis / P. secunda/B. tectorum / A. tridentata ssp. tridentata, and Agropyron cristatum / P. secunda. This EO is located roughly 23 km (14 mi) south of Boise. Most of the EO has burned at least once in the past couple of decades resulting in a mix of small-to-fairly-large shrub patches intermixed with invasive, nonnative, annual-grassland vegetation. This EO is known to be threatened by wildfire, invasive, nonnative plant species, and livestock trampling.
The plant community of EO 77 is composed of an Artemisia tridentata ssp. wyomingensis / Bromus tectorum / Poa seconda. While the EO is unburned, the surrounding area is partially burned. Bromus tectorum is growing abundantly throughout the general EO. Wildfires are the primary threat to this EO because of the existing Bromus tectorum understory. Livestock trampling of slickspots is also a continued threat.
The primary community type of EO 104 is a Bromus tectorum / Poa secunda and Chrysothamnus spp./ P. secunda / B. tectorum. This EO is located approximately 23 km (14 mi) south of Boise. Most of the EO has burned at least once in the past 20 years resulting in a mix of small to fairly large shrub patches and areas of annual grassland. Invasive, nonnative plants, wildfire, and livestock are threats to this EO.
Unit 3: Elmore County
The Elmore County unit consists of 3,998 ha (9,879 ac) divided into three subunits: 3a, 3b, and 3c. Lepidium papilliferum was known to occupy this unit at the time of listing. 3,483 ha (8,606 ac) of this unit are Federally managed, of which 3,418 ha (8,446 ac) are managed by BLM and 65 ha (160 ac) by the Bureau of Reclamation (BOR), 97 ha (239 ac) are managed by the State of Idaho, and 418 ha (1,034 ac) are privately owned. This unit is composed of 12 L. papilliferum EOs. This unit contains PCEs and is important to the conservation of L
this unit at the time of listing. 3,483 ha (8,606 ac) of this unit are Federally managed, of which 3,418 ha (8,446 ac) are managed by BLM and 65 ha (160 ac) by the Bureau of Reclamation (BOR), 97 ha (239 ac) are managed by the State of Idaho, and 418 ha (1,034 ac) are privately owned. This unit is composed of 12 L. papilliferum EOs. This unit contains PCEs and is important to the conservation of L. papilliferum because it contains EOs with good habitat, represents a significant portion of the species' range, and contains several EOs with high numbers of L. papilliferum individuals.
Subunit 3a
The northern boundary of subunit 3a is approximately 6.8 km (4.2 mi) south of Mayfield, Idaho, while the southern boundary is approximately 19.6 km (12.2 mi) northwest of Mountain Home, Idaho. Subunit 3a is composed of three EOs: 20, 30, and 31.
EO 20 is composed of Artemisia tridentata / Poa secunda / Bromus and introduced invasive, nonnative, annual-grassland communities. This EO is located adjacent to Interstate 84 and Old Highway 30. Residential development occurs within 250 m (820 ft) of the EO. Portions of this EO have burned in the past, and Agropyron cristatum drill-seeding is evident along the northeast edge of the EO. The primary threats to this EO are wildfires, invasive, nonnative weeds, and development on private lands.
The plant community of EO 30 contains a large stand of intact, mature sagebrush-steppe habitat with various size classes of Artemisia tridentata ssp. wyomingensis represented, and a grass-dominated understory. This EO is located in close proximity to Old Highway 30 and private lands. Although the EO area is unburned, the adjacent areas and surrounding landscape have been burned and are fragmented. This is a large EO with over 7,000 Lepidium papilliferum plants observed in 2000. It is known to be threatened by wildfire, invasive, nonnative plants, urban development, and recreation.
The plant community of EO 31 is composed of Artemisia tridentata spp. wyomingensis / Poa secunda, A
ough the EO area is unburned, the adjacent areas and surrounding landscape have been burned and are fragmented. This is a large EO with over 7,000 Lepidium papilliferum plants observed in 2000. It is known to be threatened by wildfire, invasive, nonnative plants, urban development, and recreation.
The plant community of EO 31 is composed of Artemisia tridentata spp. wyomingensis / Poa secunda, A. tridentata spp. wyomingensis / B. tectorum, and introduced grasses. It consists of a mid-size population in good-to-fair habitat condition. Part of the EO has burned, and the surrounding landscape is predominantly burned. This EO is threatened by wildfires, livestock trampling, private land development, and ORV use.
Subunit 3b
The boundaries of subunit 3b contain the city of Mountain Home, Idaho, while the northern boundary is approximately 63.9 km (39.7 mi) southeast of Boise, Idaho. Subunit 3b is composed of seven EOs: 2, 21, 29, 50, 51, 61, and 62.
EO 2 is composed of a large, unburned Artemisia tridentata ssp. wyomingensis / Poa secunda plant community with low-to-moderate cover of Bromus tectorum, Salsola kali, and Lepidium perfoliatum. It is located approximately 11 km (7 mi) west of Mountain Home. Wildfire and livestock disturbances are the major threats to this relatively intact EO.
EO 21 consists of a largely-intact stand of sagebrush-steppe habitat that consists of a community of native species including Artemisia tridentata ssp. wyomingensis and Poa secunda, and the introduced, nonnative plant Ceratocephala testiculata. It is located approximately 6 km (4 mi) west of Mountain Home and 1.6 km (1.0 mi) south of Interstate 84. There is low understory cover, but high biological crust cover. This occurrence has not been burned, although the surrounding landscape is predominantly burned. This EO is threatened by wildfire, invasive, nonnative, annual plant species, and recreation.
Although the overstory in the area of the third EO in this subunit, EO 29, is composed of Artemisia tridentata ssp
mi) south of Interstate 84. There is low understory cover, but high biological crust cover. This occurrence has not been burned, although the surrounding landscape is predominantly burned. This EO is threatened by wildfire, invasive, nonnative, annual plant species, and recreation.
Although the overstory in the area of the third EO in this subunit, EO 29, is composed of Artemisia tridentata ssp. wyomingensis, the understory is now dominated by Bromus tectorum. This EO is located about 3 km (2 mi) southeast of Mountain Home, between Interstate 84 (about 65 m (210 ft) away) and burned, nonnative, annual-grassland habitat. There is a fairly high biological soil crust cover of approximately 30 percent in the surrounding landscape, and slickspots also tend to have a relatively high crust cover. This EO is threatened by wildfire and invasive, nonnative plant species.
EO 50 has a largely-native-species overstory, with fairly contiguous Artemisia tridentata ssp. wyomingensis cover; however, the understory is dominated by Bromus tectorum. It is located approximately 5.6 km (3.5 mi) southeast of Mountain Home. The EO itself is unburned, although surrounding BLM and private lands have burned in the past. Slickspots are clumped in several areas within this occurrence. The surrounding landscape is fragmented due to a combination of burned areas, residential development, and agricultural lands. This EO is threatened by invasive, nonnative plant species and wildfire. Urban encroachment is occurring on adjacent, privately-owned lands, which could lead to further fragmentation of the surrounding landscape.
The plant community of EO 51 consists of a mix of native and nonnative plant species, primarily Artemisia tridentata ssp. wyomingensis in the overstory and Ceratocephala testiculata and Descurainia pinnata (western tansymustard) in the understory. It is located roughly 5 km (3 mi) east of Mountain Home. There is a low diversity and abundance of native forbs but only trace amounts of Bromus tectorum
he plant community of EO 51 consists of a mix of native and nonnative plant species, primarily Artemisia tridentata ssp. wyomingensis in the overstory and Ceratocephala testic

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-10753. Check the current official text before relying on it. Not legal advice.