# 80 FR 58536: Endangered and Threatened Wildlife and Plants; Endangered Species Status for Chamaecrista lineata var. keyensis (Big Pine Partridge Pea), Chamaesyce deltoidea ssp. serpyllum (Wedge Spurge), and Linum arenicola (Sand Flax), and Threatened Species Status for Argythamnia blodgettii (Blodgett's Silverbush)

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2015-24291

## Section

- **Citation:** 80 FR 58536
- **Heading:** Endangered and Threatened Wildlife and Plants; Endangered Species Status for Chamaecrista lineata var. keyensis (Big Pine Partridge Pea), Chamaesyce deltoidea ssp. serpyllum (Wedge Spurge), and Linum arenicola (Sand Flax), and Threatened Species Status for Argythamnia blodgettii (Blodgett's Silverbush)
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Federal Register / Vol. 80 / 80 FR 58536

## Text

DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 17 [Docket No. FWS-R4-ES-2015-0137]; [4500030113] RIN 1018-AZ95 Endangered and Threatened Wildlife and Plants; Endangered Species Status for Chamaecrista lineata var. keyensis (Big Pine Partridge Pea), Chamaesyce deltoidea ssp. serpyllum (Wedge Spurge), and Linum arenicola (Sand Flax), and Threatened Species Status for Argythamnia blodgettii (Blodgett's Silverbush) AGENCY:
Fish and Wildlife Service, Interior.

ACTION:
Proposed rule.

SUMMARY:
We, the U.S. Fish and Wildlife Service (Service or USFWS), propose to list four plants from south Florida under the Endangered Species Act of 1973, as amended (Act): Chamaecrista lineata var. keyensis (Big Pine partridge pea), Chamaesyce deltoidea ssp. serpyllum (wedge spurge), and Linum arenicola (sand flax) as endangered species, and Argythamnia blodgettii (Blodgett's silverbush) as a threatened species. If we finalize this rule as proposed, it would extend the Act's protections to these plants.

DATES:
We will accept comments received or postmarked on or before November 30, 2015. Comments submitted electronically using the Federal eRulemaking Portal (see ADDRESSES , below) must be received by 11:59 p.m. Eastern Time on the closing date. We must receive requests for public hearings, in writing, at the address shown in FOR FURTHER INFORMATION CONTACT by November 13, 2015.

ADDRESSES:
You may submit comments by one of the following methods:
(1) Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov. In the Search box, enter FWS-R4-ES-2015-0137, which is the docket number for this rulemaking. Then, in the Search panel on the left side of the screen, under the Document Type heading, click on the Proposed Rules link to locate this document. You may submit a comment by clicking on “Comment Now!”
wing methods:
(1) Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov. In the Search box, enter FWS-R4-ES-2015-0137, which is the docket number for this rulemaking. Then, in the Search panel on the left side of the screen, under the Document Type heading, click on the Proposed Rules link to locate this document. You may submit a comment by clicking on “Comment Now!”
(2) By hard copy: Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS-R4-ES-2015-0137; U.S. Fish and Wildlife Service, MS: BPHC, 5275 Leesburg Pike, Falls Church, VA 22041-3803.
We request that you send comments only by the methods described above. We will post all comments on http://www.regulations.gov. This generally means that we will post any personal information you provide us (see Public Comments, below, for more information).
FOR FURTHER INFORMATION CONTACT:
Larry Williams, State Supervisor, U.S. Fish and Wildlife Service, South Florida Ecological Services Field Office, 1339 20th Street, Vero Beach, FL 32960; by telephone 772-562-3909; or by facsimile 772-562-4288. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Executive Summary
Why we need to publish a rule. Under the Act, if we determine that a species is an endangered or threatened species throughout all or a significant portion of its range, we must publish a proposed rule to list the species in the Federal Register and make a determination on our proposal within 1 year. Listing a species as an endangered or threatened species can only be completed by issuing a rule.
This rule proposes the listing of Chamaecrista lineata var. keyensis, Chamaesyce deltoidea ssp. serpyllum, and Linum arenicola as endangered species, and Argythamnia blodgettii as a threatened species
to list the species in the Federal Register and make a determination on our proposal within 1 year. Listing a species as an endangered or threatened species can only be completed by issuing a rule.
This rule proposes the listing of Chamaecrista lineata var. keyensis, Chamaesyce deltoidea ssp. serpyllum, and Linum arenicola as endangered species, and Argythamnia blodgettii as a threatened species. The four plants are candidate species for which we have on file sufficient information on biological vulnerability and threats to support preparation of a listing proposal, but for which development of a listing rule has until now been precluded by other higher priority listing activities. This rule reassesses all available information regarding status of and threats to the four plants.
The basis for our action. Under the Act, we may determine that a species is an endangered or threatened species based on any of five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; or (E) other natural or manmade factors affecting its continued existence. We have determined that the threats to Chamaecrista lineata var. keyensis, Chamaesyce deltoidea ssp. serpyllum, Linum arenicola, and Argythamnia blodgettii consist primarily of habitat loss and modification through urban and agricultural development, and lack of adequate fire management (Factor A); and the proliferation of nonnative invasive plants, stochastic events (hurricanes and storm surge), maintenance practices used on roadsides and disturbed sites, and sea level rise (Factor E). Existing regulatory mechanisms have not been adequate to reduce or remove these threats (Factor D).
We will seek peer review. We will seek comments from independent specialists to ensure that our determinations are based on scientifically sound data, assumptions, and analyses
(hurricanes and storm surge), maintenance practices used on roadsides and disturbed sites, and sea level rise (Factor E). Existing regulatory mechanisms have not been adequate to reduce or remove these threats (Factor D).
We will seek peer review. We will seek comments from independent specialists to ensure that our determinations are based on scientifically sound data, assumptions, and analyses. We will invite these peer reviewers to comment on this listing proposal.
Information Requested
Public Comments
We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from other concerned governmental agencies, Native American tribes, the scientific community, industry, or any other interested parties concerning this proposed rule. We particularly seek comments concerning:
(1) The four plants' biology, range, and population trends, including:
(a) Biological or ecological requirements of these plants, including habitat requirements for establishment, growth, and reproduction;
(b) Genetics and taxonomy;
(c) Historical and current ranges, including distribution patterns;
(d) Historical and current population levels, and current and projected trends; and
(e) Past and ongoing conservation measures for the plants, their habitats, or both.
(2) Factors that may affect the continued existence of these plants, which may include habitat modification or destruction, overutilization, disease, predation, the inadequacy of existing regulatory mechanisms, or other natural or manmade factors.
(3) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to these plants and existing regulations that may be addressing those threats.
(4) Current or planned activities in the areas occupied by these plants and possible impacts of these activities on these plants.
, the inadequacy of existing regulatory mechanisms, or other natural or manmade factors.
(3) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to these plants and existing regulations that may be addressing those threats.
(4) Current or planned activities in the areas occupied by these plants and possible impacts of these activities on these plants.
(5) Additional information concerning the biological or ecological requirements
(6) Scientific information or analysis informing whether these plants more closely meet the definition of endangered or of threatened under the Act.
Please include sufficient information with your submission (such as scientific journal articles or other publications) to allow us to verify any scientific or commercial information you include.
Please note that submissions merely stating support for or opposition to the action under consideration without providing supporting information, although noted, will not be considered in making a determination, as section 4(b)(1)(A) of the Act (16 U.S.C. 1531 et seq. ) directs that determinations as to whether any species is an endangered or threatened species must be made “solely on the basis of the best scientific and commercial data available.”
You may submit your comments and materials concerning this proposed rule by one of the methods listed in the ADDRESSES section. We request that you send comments only by the methods described in the ADDRESSES section.
If you submit information via http://www.regulations.gov, your entire submission—including any personal identifying information—will be posted on the Web site. If your submission is made via a hardcopy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy submissions on http://www.regulations.gov
ssion—including any personal identifying information—will be posted on the Web site. If your submission is made via a hardcopy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy submissions on http://www.regulations.gov.
Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on http://www.regulations.gov, or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, South Florida Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT ).
Public Hearing
Section 4(b)(5) of the Act provides for one or more public hearings on this proposal, if requested. Requests must be received within 45 days after the date of publication of this proposed rule in the Federal Register . Such requests must be sent to the address shown in the FOR FURTHER INFORMATION CONTACT section. We will schedule public hearings on this proposal, if any are requested, and announce the dates, times, and places of those hearings, as well as how to obtain reasonable accommodations, in the Federal Register and local newspapers at least 15 days before the hearing.
Peer Review
In accordance with our joint policy on peer review published in the Federal Register on July 1, 1994 (59 FR 34270), we will seek the expert opinions of at least three appropriate and independent specialists regarding this proposed rule. The purpose of peer review is to ensure that our listing determinations are based on scientifically sound data, assumptions, and analyses. The peer reviewers have expertise in the biology, habitat, and conservation status of these plants, which will inform our determinations. We invite comment from the peer reviewers during the public comment period
endent specialists regarding this proposed rule. The purpose of peer review is to ensure that our listing determinations are based on scientifically sound data, assumptions, and analyses. The peer reviewers have expertise in the biology, habitat, and conservation status of these plants, which will inform our determinations. We invite comment from the peer reviewers during the public comment period.
Previous Federal Actions
On January 9, 1975, as directed by the Act, the Secretary for the Smithsonian Institution submitted a report to Congress on potential endangered and threatened plant species of the United States (Smithsonian 1975, entire). The report identified more than 3,000 plant species as potentially either endangered or threatened, including Argythamnia blodgettii, Chamaecrista lineata var. keyensis (under the former name Cassia keyensis ), Chamaesyce deltoidea ssp. serpyllum (under the name Chamaesyce ( Euphorbia ) deltoidea ssp. serpyllum ), and Linum arenicola (Smithsonian 1975, pp. 56, 58, 61, 81). On July 1, 1975, we published in the Federal Register (40 FR 27824) our notification that we considered this report to be a petition to list the identified plants as either endangered or threatened under the Act. The 1975 notice solicited information from Federal and State agencies, and the public, on the status of the species.
On December 15, 1980, we published in the Federal Register (45 FR 82480) our notice of review of plant taxa for listing as endangered or threatened species. In that document, Argythamnia blodgettii, Chamaecrista lineata var. keyensis (under the former name Cassia keyensis ), Chamaesyce deltoidea ssp. serpyllum (under the former name Euphorbia deltoidea ssp. serpyllum ), and Linum arenicola were identified as Category 1 species (taxa for which we had enough biological information to support listing as either endangered or threatened). As a result, we considered all four plants to be candidates for addition to the Federal List of Endangered and Threatened Plants
nsis ), Chamaesyce deltoidea ssp. serpyllum (under the former name Euphorbia deltoidea ssp. serpyllum ), and Linum arenicola were identified as Category 1 species (taxa for which we had enough biological information to support listing as either endangered or threatened). As a result, we considered all four plants to be candidates for addition to the Federal List of Endangered and Threatened Plants. The 1980 notice solicited information from Federal and State agencies, and the public, on the status of the four plant species.
On November 28, 1983, we published a document in the Federal Register (48 FR 53640) assigning a listing priority number (LPN) to two of the four plant species in accordance with our Listing Priority Guidance (48 FR 43098; September 21, 1983). Argythamnia blodgettii and Linum arenicola were assigned an LPN of 2, which meant that information that the Service possessed indicated that proposing to list as endangered or threatened was possibly appropriate but we lacked substantial information on biological vulnerability and threat(s) to support a proposed listing.
On September 27, 1985, we published a document in the Federal Register (50 FR 39526) assigning LPNs to all four of the plant species in accordance with our Listing Priority Guidance (48 FR 43098; September 21, 1983). Argythamnia blodgettii and Linum arenicola both retained an LPN of 2, which meant that information that the Service possessed indicated that proposing to list as endangered or threatened was possibly appropriate but we lacked substantial information on biological vulnerability and threat(s) to support a proposed listing. Chamaecrista lineata var. keyensis (under the former name Cassia keyensis ) and Chamaesyce deltoidea ssp. serpyllum (under the former name Euphorbia deltoidea ssp. serpyllum ) were both assigned an LPN of 1, which meant the Service had on file substantial information on biological vulnerability and threat(s) to support the appropriateness of proposing to list as endangered or threatened
d listing. Chamaecrista lineata var. keyensis (under the former name Cassia keyensis ) and Chamaesyce deltoidea ssp. serpyllum (under the former name Euphorbia deltoidea ssp. serpyllum ) were both assigned an LPN of 1, which meant the Service had on file substantial information on biological vulnerability and threat(s) to support the appropriateness of proposing to list as endangered or threatened. We recognized at that time that any proposed listing action may take “some years” because of the “large number of taxa” at issue.
The 1990 candidate notice of review (CNOR) published in the Federal Register on February 21, 1990 (55 FR 6184). In that CNOR, Argythamnia blodgettii and Linum arenicola both retained an LPN of 2, and Chamaecrista lineata var. keyensis and Chamaesyce deltoidea ssp. serpyllum both retained an LPN of 1. Candidate species are assigned LPNs based on immediacy and magnitude of threats, as well as taxonomic status. The lower the LPN, the higher priority that species is for us to determine appropriate action using our available resources. We determined at that time that proposing to list was warranted, but was precluded due to workloads and priorities.
All four plants remained on the candidate list in the 1993 CNOR (58 FR 51144; September 30, 1993), with Argythamnia blodgettii and Linum arenicola both retaining an LPN of 2, and Chamaecrista lineata var. keyensis Chamaesyce deltoidea ssp. serpyllum being assigned an LPN of 3C (taxa that have proven to be more abundant or widespread than previously believed and/or those that are not subject to any identifiable threat).
The 1999 CNOR (64 FR 57534; October 25, 1999) retained Chamaecrista lineata var. keyensis and Chamaesyce deltoidea ssp. serpyllum as candidates and assigned an LPN of 6 to both, retained Linum arenicola as a candidate and assigned an LPN of 2, and retained Argythamnia blodgettii as a candidate and assigned an LPN of 11.
Chamaecrista lineata var. keyensis and Chamaesyce deltoidea ssp
e threat).
The 1999 CNOR (64 FR 57534; October 25, 1999) retained Chamaecrista lineata var. keyensis and Chamaesyce deltoidea ssp. serpyllum as candidates and assigned an LPN of 6 to both, retained Linum arenicola as a candidate and assigned an LPN of 2, and retained Argythamnia blodgettii as a candidate and assigned an LPN of 11.
Chamaecrista lineata var. keyensis and Chamaesyce deltoidea ssp. serpyllum remained on the candidate list from 2001 to 2006, with the LPN of 6 (66 FR 54808, October 30, 2001; 67 FR 40657, June 13, 2002; 69 FR 24876, May 4, 2004; 70 FR 24870, May 11, 2005; 71 FR 53756, September 12, 2006). In the December 6, 2007, CNOR (72 FR 69034), we changed the LPN of Chamaecrista lineata var. keyensis and Chamaesyce deltoidea ssp. serpyllum from a 6 to a 9 because the threats to the species were found to be of lower magnitude than previously known. Chamaecrista lineata var. keyensis and Chamaesyce deltoidea ssp. serpyllum remained on the candidate list as published in the CNORs from 2008 to 2014 with the LPN of 9 (73 FR 75176, December 10, 2008; 74 FR 57804, November 9, 2009; 75 FR 69222, November 10, 2010; 76 FR 66370, October 26, 2011; 77 FR 69994, November 21, 2012; 78 FR 70104, November 22, 2013; 79 FR 72450, December 5, 2014).
Linum arenicola remained on the candidate list from 2001 to 2009, with the LPN of 2 (66 FR 54808, October 30, 2001; 67 FR 40657, June 13, 2002; 69 FR 24876, May 4, 2004; 70 FR 24870, May 11, 2005; 71 FR 53756, September 12, 2006; 72 FR 69034, December 6, 2007; 73 FR 75176, December 10, 2008; 74 FR 57804, November 9, 2009). In the November 10, 2010, CNOR (75 FR 69222), we changed the LPN of L. arenicola from a 2 to a 5 because of the threats to the species were found to be of lower magnitude than previously known and new data showing a larger population. L
4, 2004; 70 FR 24870, May 11, 2005; 71 FR 53756, September 12, 2006; 72 FR 69034, December 6, 2007; 73 FR 75176, December 10, 2008; 74 FR 57804, November 9, 2009). In the November 10, 2010, CNOR (75 FR 69222), we changed the LPN of L. arenicola from a 2 to a 5 because of the threats to the species were found to be of lower magnitude than previously known and new data showing a larger population. L. arenicola remained on the candidate list as published in the CNORs from 2011 to 2014 with the LPN of 5 (76 FR 66370, October 26, 2011; 77 FR 69994, November 21, 2012; 78 FR 70104, November 22, 2013; 79 FR 72450, December 5, 2014).
Argythamnia blodgettii remained on the candidate list from 2001 to 2014, with the LPN of 11 (66 FR 54808, October 30, 2001; 67 FR 40657, June 13, 2002; 69 FR 24876, May 4, 2004; 70 FR 24870, May 11, 2005; 71 FR 53756; September 12, 2006; 72 FR 69034, December 6, 2007; 73 FR 75176, December 10, 2008; 74 FR 57804, November 9, 2009; 75 FR 69222, November 10, 2010; 76 FR 66370, October 26, 2011; 77 FR 69994, November 21, 2012; 78 FR 70104, November 22, 2013; 79 FR 72450, December 5, 2014).
For all four of the plant species, the 2005 CNOR (70 FR 24870; May 11, 2005) included a “warranted but precluded” finding in response to a May 11, 2004, petition to list the species.
On May 10, 2011, as part of a settlement agreement with a plaintiff, the Service filed a proposed work plan with the U.S. District Court for the District of Columbia. The work plan would enable the agency to, over a period of 6 years, systematically review and address the needs of more than 250 species listed within the 2010 CNOR, including Chamaecrista lineata var. keyensis, Chamaesyce deltoidea ssp. serpyllum, Linum arenicola, and Argythamnia blodgettii, to determine if these species should be added to the Federal Lists of Endangered and Threatened Wildlife and Plants
plan would enable the agency to, over a period of 6 years, systematically review and address the needs of more than 250 species listed within the 2010 CNOR, including Chamaecrista lineata var. keyensis, Chamaesyce deltoidea ssp. serpyllum, Linum arenicola, and Argythamnia blodgettii, to determine if these species should be added to the Federal Lists of Endangered and Threatened Wildlife and Plants. This work plan would enable the Service to again prioritize its workload based on the needs of candidate species, while also providing State wildlife agencies, stakeholders, and other partners clarity and certainty about when listing determinations will be made. On July 12, 2011, the Service reached an agreement with another plaintiff group and further strengthened the work plan, which would allow the agency to focus its resources on the species most in need of protection under the Act. These agreements were approved by the court on September 9, 2011. The four species are proposed for listing pursuant to these agreements.
Background
It is our intent to discuss below only those topics directly relevant to the listing of Chamaecrista lineata var. keyensis, Chamaesyce deltoidea ssp. serpyllum, and Linum arenicola as endangered, and Argythamnia blodgettii as threatened, in this proposed rule.
Chamaecrista lineata var. keyensis (Big Pine partridge pea)
Species Description
Chamaecrista lineata var. keyensis is a small, prostrate to ascending, perennial, herbaceous shrub that is 10-80 centimeters (cm) (3.9-31.5 inches (in)) tall, with yellow flowers and pinnately compound leaves (each leaf consists of a main stem with multiple leaflets lined up along on each side). It has one to several branched stems arising from a contorted rootstock. New branches are covered in soft, fuzzy hairs. The leaves are 1.7-4.0 cm (0.7-1.6 in) long, with 5 to 9 pairs of leaflets
s shrub that is 10-80 centimeters (cm) (3.9-31.5 inches (in)) tall, with yellow flowers and pinnately compound leaves (each leaf consists of a main stem with multiple leaflets lined up along on each side). It has one to several branched stems arising from a contorted rootstock. New branches are covered in soft, fuzzy hairs. The leaves are 1.7-4.0 cm (0.7-1.6 in) long, with 5 to 9 pairs of leaflets. Flowers consist of five sepals 9-20 mm (0.4-0.8 in) long that are fused together near their bases; five yellow petals 11-15 mm (0.4-0.6 in) long, with one slightly larger than the others; 10 reddish-purple stamens; and a single, elongate style. The fruit is an elongate pod, roughly similar to that of a pea, 33-45 mm (1.3-1.8 in) long and 4.5-5.0 mm (0.19-0.17 in) wide, with a soft fuzzy texture, which turns gray with age and eventually split open to release seeds (Irwin and Barneby 1982, p. 757; Small 1933, pp. 662-663).
Taxonomy
John Loomis Blodgett was the first to collect Chamaecrista lineata var. keyensis, sometime between 1838 and 1852, on Big Pine Key (Bradley and Gann 1999, p. 17). Pollard (1894, p. 217) assigned the plants on Big Pine Key to the existing taxon Cassia grammica. John K. Small (1903, p. 587; 1913, p. 58) followed this usage, but used the genus Chamaecrista (considered a subgenus within Cassia or a genus unto itself variously by many authors). In 1917, Pennell (p. 344) recognized the Big Pine Key plant as a distinct endemic species, naming it Chamaecrista keyensis. This name was retained by Small (1933, p. 663) in his Manual of the Southeastern Flora. In an exhaustive study of Cassia and Chamaecrista, Irwin and Barneby (1982, p. 757) assigned plants in Florida and parts of the West Indies to the existing taxon Chamaecrista lineata, and assigned the Big Pine Key plants to var. keyensis, retaining them as endemic to the Florida Keys. Isely (1990, p. 33), Wunderlin (1998, p. 348), and Wunderlin and Hansen (2003, p. 441) have followed this treatment
n an exhaustive study of Cassia and Chamaecrista, Irwin and Barneby (1982, p. 757) assigned plants in Florida and parts of the West Indies to the existing taxon Chamaecrista lineata, and assigned the Big Pine Key plants to var. keyensis, retaining them as endemic to the Florida Keys. Isely (1990, p. 33), Wunderlin (1998, p. 348), and Wunderlin and Hansen (2003, p. 441) have followed this treatment. The online Atlas of Florida Vascular Plants (Wunderlin and Hansen 2014, p. 1) uses Chamaecrista lineata var. keyensis. The Integrated Taxonomic Information System (2015, p. 1) uses the name Chamaecrista lineata var. keyensis and indicates that this taxonomy is accepted. Based upon the best available scientific information, Chamaecrista lineata var. keyensis is a distinct taxon, endemic to the lower Keys in Monroe County, Florida. Synonyms are Cassia keyensis (Pennell) J.F. Macbr and Chamaecrista keyensis Pennell. Chamaecrista lineata var. keyensis is related to, and superficially resembles, Chamaecrista fasciculata, the partridge pea, a common species which occurs throughout Florida.
Climate
The climate of south Florida where Chamaecrista lineata var. keyensis occurs is classified as tropical savanna and is characterized by distinct wet and dry seasons and a monthly mean temperature above 18 degrees Celsius (°C) (64.4 degrees Fahrenheit (°F)) in every month of the year (Gabler et al. 1994, p. 211). Freezes can occur in the winter months, but are rare at this latitude in south Florida. Rainfall in the lower Keys, where C. lineata var. keyensis occurs exclusively, varies from an annual average of 89-102 cm (35-40 in). Approximately 75 percent of yearly rainfall occurs during the wet season from June through September (Snyder et al. 1990, p. 238).
Habitat
Chamaecrista lineata var. keyensis occurs in pine rocklands of the lower Florida Keys, and adjacent disturbed sites, including roadsides
he lower Keys, where C. lineata var. keyensis occurs exclusively, varies from an annual average of 89-102 cm (35-40 in). Approximately 75 percent of yearly rainfall occurs during the wet season from June through September (Snyder et al. 1990, p. 238).
Habitat
Chamaecrista lineata var. keyensis occurs in pine rocklands of the lower Florida Keys, and adjacent disturbed sites, including roadsides.
Pine Rocklands: Pine rocklands are a unique and highly imperiled ecosystem found on limestone substrates in south Florida and a few islands in the Bahamas. In Florida, pine rocklands are located on the Miami Rock Ridge in present day Miami and in Everglades National Park, in the Florida Keys, and in the Big Cypress Swamp. While all four plants in this proposed rule occur primarily in pine rocklands, they have not been recorded in the Big Cypress Swamp area. Pine rocklands differ to some degree between and within these areas with regard to substrate ( e.g., amount of exposed limestone, type of soil), elevation, hydrology, and species composition (both plant and animal).
Pine rocklands occur in a mosaic with primarily two other natural community types—rockland hammock and marl prairie. Pine rocklands grade into rockland hammock; pine rocklands have an open pine canopy, and rockland hammock has a closed, hardwood canopy. Marl prairies differ from pine rocklands in having no pines, an understory dominated by grasses and sedges, and a minimal cover of shrubs (FNAI 2010, p. 63).
The total remaining acreage of pine rocklands in Miami-Dade and Monroe Counties is now 8,981 hectares (ha) (22,079 acres (ac)) (approximately 8,140 ha (20,100 ac)) in Miami-Dade County, and 801 ha (1,979 ac) in the Florida Keys (Monroe County).
Pine rocklands are characterized by an open canopy of Pinus elliottii var. densa (South Florida slash pine) with a patchy understory of tropical and temperate shrubs and palms and a rich herbaceous layer of mostly perennial species, including numerous species endemic to South Florida
roximately 8,140 ha (20,100 ac)) in Miami-Dade County, and 801 ha (1,979 ac) in the Florida Keys (Monroe County).
Pine rocklands are characterized by an open canopy of Pinus elliottii var. densa (South Florida slash pine) with a patchy understory of tropical and temperate shrubs and palms and a rich herbaceous layer of mostly perennial species, including numerous species endemic to South Florida. Outcrops of weathered oolitic (small, rounded particles or grains) limestone are common, and solution holes may be present. This subtropical, pyrogenic flatland can be mesic or xeric depending on landscape position and associated natural communities (FNAI 2010a, p. 1).
Pine rocklands occur on relatively flat, moderately to well-drained terrain from 2-7 meters (m) (6.5 to 23 feet (ft)) above sea level (FNAI 2010a, p. 2). The oolitic limestone is at or very near the surface, and there is very little soil development. Soils are generally composed of small accumulations of nutrient-poor sand, marl, clayey loam, and organic debris in depressions and crevices in the rock surface. Organic acids occasionally dissolve the surface limestone causing collapsed depressions in the surface rock called solution holes (FNAI 2010a, p. 1). Drainage varies according to the porosity of the limestone substrate, but is generally rapid. Consequently, most sites are wet for only short periods following heavy rains. During the rainy season, however, some sites may be shallowly inundated by slow-flowing surface water for up to 60 days each year (FNAI 2010a, p. 1).
Pine rocklands have an open canopy of South Florida slash pine, generally with multiple age classes. The diverse, open shrub and subcanopy layer is composed of more than 100 species of palms and hardwoods (FNAI 2010a, p. 1), most derived from the tropical flora of the West Indies (FNAI 2010a, p. 1). Many of these species vary in height depending on fire frequency, getting taller with time since fire
ne rocklands have an open canopy of South Florida slash pine, generally with multiple age classes. The diverse, open shrub and subcanopy layer is composed of more than 100 species of palms and hardwoods (FNAI 2010a, p. 1), most derived from the tropical flora of the West Indies (FNAI 2010a, p. 1). Many of these species vary in height depending on fire frequency, getting taller with time since fire. These may include Serenoa repens (saw palmetto), Sabal palmetto (cabbage palm), Coccothrinax argentata (silver palm), Thrinax morrisii (Key thatch palm), Myrica cerifera (wax myrtle), Rapanea punctata (myrsine), Metopium toxiferum (poisonwood), Byrsonima lucida (locustberry), Dodonaea viscosa (varnishleaf), Tetrazygia bicolor (tetrazygia), Guettarda scabra (rough velvetseed), Ardisia escallonioides (marlberry), Psidium longipes (longstalked stopper), Sideroxylon salicifolium (willow bustic), and Rhus copallinum (winged sumac). Short-statured shrubs may include Quercus elliottii (running oak), Randia aculeata (white indigoberry), Crossopetalum ilicifolium (Christmas berry), Morinda royoc (redgal), and Chiococca alba (snowberry).
Grasses, forbs, and ferns make up a diverse herbaceous layer ranging from mostly continuous in areas with more soil development and little exposed rock to sparse where more extensive outcroppings of rock occur. Typical herbaceous species may include Andropogon spp.; Schizachyrium gracile, S. rhizomatum, and S. sanguineum (bluestem grasses); Aristida purpurascens (arrowleaf threeawn); Sorghastrum secundum (lopsided indiangrass); Muhlenbergia capillaris (hairawn muhly); Rhynchospora floridensis (Florida white-top sedge); Tragia saxicola (pineland noseburn); Echites umbellata (devil's potato); Croton linearis (pineland croton); several species of Chamaesyce spp. (sandmats); Chamaecrista fasciculata (partridge pea); Zamia pumila (coontie); Anemia adiantifolia (maidenhair pineland fern); Pteris bahamensis (Bahama brake); and Pteridium aquilinum var. caudatum (lacy bracken) (FNAI 2010a, p. 1)
Florida white-top sedge); Tragia saxicola (pineland noseburn); Echites umbellata (devil's potato); Croton linearis (pineland croton); several species of Chamaesyce spp. (sandmats); Chamaecrista fasciculata (partridge pea); Zamia pumila (coontie); Anemia adiantifolia (maidenhair pineland fern); Pteris bahamensis (Bahama brake); and Pteridium aquilinum var. caudatum (lacy bracken) (FNAI 2010a, p. 1).
There are noticeable differences in species composition between the pine rocklands found in the Florida Keys and the mainland. The shrub layer in pine rocklands occurring in the northern end of the Miami Rock Ridge more closely resembles pine flatwoods as a result of the amount of sandy soils in this area, with species such as Lyonia fruticosa (staggerbush), Quercus minima (dwarf live oak), Quercus pumila (running oak), and Vaccinium myrsinites (shiny blueberry) becoming more common (Snyder et al. 1990, p. 255). Pine rocklands in the lower Florida Keys have a subcanopy composed of several palms such as Thrinax morrisii, Thrinax radiata (Florida thatch palm), and Coccothrinax argentata, and hardwoods such as Byrsonima lucida and Psidium longipes (Bradley 2006, p. 3). The diversity of the herbaceous layer decreases as the density of the shrub layer increases ( i.e., as understory openness decreases), and pine rocklands on the mainland have a more diverse herbaceous layer due to the presence of temperate species and some tropical species that do not occur in the Florida Keys (FNAI 2010, p. 63).
Pine rocklands are maintained by regular fire, and are susceptible to other natural disturbances such as hurricanes, frost events, and sea level rise (SLR) (Ross et al. 1994). Fires historically burned on an interval of approximately every 3 to 7 years, and were typically started by lightning strikes during the frequent summer thunderstorms (FNAI 2010a, p. 3). Mature South Florida slash pine is highly fire-resistant (Snyder et al. 1990, p. 259)
nd are susceptible to other natural disturbances such as hurricanes, frost events, and sea level rise (SLR) (Ross et al. 1994). Fires historically burned on an interval of approximately every 3 to 7 years, and were typically started by lightning strikes during the frequent summer thunderstorms (FNAI 2010a, p. 3). Mature South Florida slash pine is highly fire-resistant (Snyder et al. 1990, p. 259). Above-ground portions of hardwood shrubs are typically killed by fire, but often resprout below ground; palms typically produce new growth post-fire from their unaffected apical buds. The amount of woody understory growth is directly related to the length
Pine rocklands are also susceptible to natural disturbances such as hurricanes and other severe storms, during which trees may be killed, thereby helping to maintain the open canopy that is essential to pine rocklands plants. During such events, pine rocklands near the coast may be temporarily inundated by saltwater, which can also kill or damage vegetation (Snyder et al. 1990, p. 251). These sporadic but potentially major disturbances, along with burning, create the dynamic nature of the pine rocklands habitat. Some currently unsuitable areas may become open in the future, while areas currently open may develop more dense canopy over time, eventually rendering that portion of the pine rocklands unsuitable for pine rocklands endemic plants.
Within pine rocklands habitat, Chamaecrista lineata var. keyensis is associated with areas that have few hardwoods and overstory palms are abundant (Bradley and Gann 1999, p 17-18). C. lineata var. keyensis plants are often in a clumped distribution surrounded by large areas of bare, open rock that do not support plant growth (Bradley 2006, p. 3). C. lineata var. keyensis is widespread in pine rocklands of Big Pine Key, but more frequent in the northern part of the island (Bradley 2006, p. 13). It is also more frequent in the interior of pine rocklands than on coastal edges (Bradley 2006, p. 13; Bradley and Saha 2009, p. 9)
umped distribution surrounded by large areas of bare, open rock that do not support plant growth (Bradley 2006, p. 3). C. lineata var. keyensis is widespread in pine rocklands of Big Pine Key, but more frequent in the northern part of the island (Bradley 2006, p. 13). It is also more frequent in the interior of pine rocklands than on coastal edges (Bradley 2006, p. 13; Bradley and Saha 2009, p. 9). C. lineata var. keyensis is more abundant in areas with relatively higher elevation (Bradley and Saha 2009, p. 26), low shrub density, and a diverse herb layer (Bradley 2006, p. 37).
Roadsides: Roadsides are a potentially important habitat for Chamaecrista lineata var. keyensis (Bradley 2006, p. 21). Where pine rocklands endemics such as C. lineata var. keyensis are found on road shoulders, the ground cover is dominated mostly by native herbs and grasses, and exotic lawn grasses have not been planted. Maintaining the roadsides in this condition through regular mowing, without planting sod, should continue to provide suitable habitat for C. lineata var. keyensis (Bradley 2006, p. 37).
Historical Range
Chamaecrista lineata var. keyensis is endemic to the lower Florida Keys in Monroe County, Florida. Historical records exist for occurrences on five islands: Big Pine Key, No Name Key, Ramrod Key, Cudjoe Key, and Sugarloaf Key (Hodges and Bradley 2006, pp. 20-21).
Current Range, Population Estimates, and Status
The current range of Chamaecrista lineata var. keyensis is Big Pine Key and Cudjoe Key. In 2007, Bradley and Saha (2009, pp. 9-11) surveyed Big Pine Key, Cudjoe Key, Little Pine Key, No Name Key, and Sugarloaf Key (the five islands in the Florida Keys containing pine rocklands) and observed C. lineata var. keyensis only on Big Pine Key and Cudjoe Key. It has not been reported from other islands for some time (Ramrod Key in 1911, No Name Key in 1916 (Hodges and Bradley 2006, p. 45), and Lower Sugarloaf Key in 2005 (Hodges and Bradley 2006, p. 21)). Accordingly, C. lineata var
, No Name Key, and Sugarloaf Key (the five islands in the Florida Keys containing pine rocklands) and observed C. lineata var. keyensis only on Big Pine Key and Cudjoe Key. It has not been reported from other islands for some time (Ramrod Key in 1911, No Name Key in 1916 (Hodges and Bradley 2006, p. 45), and Lower Sugarloaf Key in 2005 (Hodges and Bradley 2006, p. 21)). Accordingly, C. lineata var. keyensis is considered extirpated from Ramrod Key, No Name Key, and Lower Sugarloaf Key—3 of 5 (60 percent) of the islands where it was historically recorded (Bradley and Gann 1999, p. 18; Hodges and Bradley 2006, p. 21). Big Pine Key, Cudjoe Key, Little Pine Key, No Name Key, and Sugarloaf Key presently contain pine rocklands habitat. No pine rocklands currently exist on Ramrod Key.
Population data for Chamaecrista lineata var. keyensis have been collected periodically on Big Pine Key since 1955. Because of the size of Big Pine Key, sample study plots were used, as opposed to a complete search of all potential habitat. Multiple indicators show that the population on Big Pine Key has declined over the past 60 years (Bradley 2006, p. 35). Dickson (1955) and Alexander and Dickson (1972) reported densities of C. lineata var. keyensis from plots they established on Big Pine Key in 1951 and 1969, respectively. Dickson (1955) reports a mean density of 10,764 plants/ha (26,599 plants/ac). Alexander and Dickson (1972) report a mean density of 27,871 plants/ha (68,872 plants/ac). In 2005, Bradley (2006, p. 35) recorded 2,339 plants/ha (5,780 plants/ac), 23.4 percent and 9.0 percent of the 1955 and 1972 estimates, respectively. Hurricane Wilma, which passed over Big Pine Key on October 24, 2005, generated storm surge in the lower Keys of up to 10 feet (Bradley 2006, p. 11; Hodges 2010, p. 4). In 2007, density had dropped to 820 plant/ha (2,026 plants/ac) and had not fully rebounded after 9 years (Bradley et al. 2015, pp. 21-22). By 2013, density had fallen to 657 plants/ha (1,624 plants/ac) (Bradley et al. 2015, p. 21)
. Hurricane Wilma, which passed over Big Pine Key on October 24, 2005, generated storm surge in the lower Keys of up to 10 feet (Bradley 2006, p. 11; Hodges 2010, p. 4). In 2007, density had dropped to 820 plant/ha (2,026 plants/ac) and had not fully rebounded after 9 years (Bradley et al. 2015, pp. 21-22). By 2013, density had fallen to 657 plants/ha (1,624 plants/ac) (Bradley et al. 2015, p. 21). In summary, the data from 2005 to 2013 demonstrate a 63.8 percent decline in the density of C. lineata var. keyensis on Big Pine Key (Bradley et al. 2015, p. 48).
A second indicator, the frequency which Chamaecrista lineata var. keyensis occurred in sample plots on Big Pine Key from data collected in 2005, 2007, and 2013, also show a decline. Chamaecrista lineata var. keyensis was present in 37 percent of plots in 2005, and 19 percent of plots in 2013, respectively. This represents a 49 percent reduction in the species frequency in study plots (Bradley et al. 2015, p. 48).
A third indicator, total population size for Chamaecrista lineata var. keyensis on publicly owned pine rocklands on Big Pine Key (478 ha (1,181 ac)), was estimated to be 866,659 plants in 2005 (pre-Hurricane Wilma), 391,944 in 2007 (2 years post-Wilma), and 313,914 in 2013 (8 years post-Wilma). This represents a population decrease of 64 percent (Bradley et al. 2015, p. 21).
The most recent estimate (2013) of the Chamaecrista lineata var. keyensis population on Big Pine Key is 313,914 plants (Bradley et al. 2015, p. 21). Since 82 percent of the pine rocklands on Big Pine Key are publicly owned, this estimate likely accounts for the majority of the population. The most recent estimate of the population on Cudjoe Key is 150 plants (Hodges and Bradley 2006, p. 21).
The decline in Chamaecrista lineata var. keyensis can be largely attributed to loss of pine rocklands habitat to development and modification of this habitat due to inadequate fire management. Folk (1991, p
are publicly owned, this estimate likely accounts for the majority of the population. The most recent estimate of the population on Cudjoe Key is 150 plants (Hodges and Bradley 2006, p. 21).
The decline in Chamaecrista lineata var. keyensis can be largely attributed to loss of pine rocklands habitat to development and modification of this habitat due to inadequate fire management. Folk (1991, p. 188) estimated that pine rocklands historically covered 1,049 ha (2,592 ac), about 44 percent of Big Pine Key. Pine rocklands now cover approximately 582 ha (1,438 ac) of Big Pine Key, 56 percent of the historical estimate by Folk (1991) (Bradley 2006, p. 4). Hurricanes and associated storm surge have also impacted population levels. These factors are discussed in detail below,
Table 1—Summary of the Status and Trends of the Known Occurrences of Chamaecrista lineata var. keyensis Population Ownership Most recent population estimate Status Trend Big Pine Key USFWS, 1 FWC 2 Monroe County, private 313, 914 (2014) 4 Extant 4 Declining. 4 Cudjoe Key USFWS, 1 FWC 2 150 (2005) 3 Extant 3 Insufficient data. Lower Sugar Loaf Key USFWS, 1 FWC 2 , Monroe County 3 (2005) 3 Extirpated 3 No Name Key unknown no data (1916) 3 Extirpated 3 Ramrod Key unknown no data (1911) 3 Extirpated 3 1 U.S. Fish and Wildlife Service. 2 Florida Fish and Wildlife Conservation Commission. 3 Hodges and Bradley 2006, p. 45. 4 Bradley et al. 2015, p. 21. Biology
The reproductive biology and relationship to fire of Chamaecrista lineata var. keyensis has received a considerable amount of study. Significant findings are summarized below.
Life History and Reproduction: Chamaecrista lineata var. keyensis is a perennial, but some stems will die back every year, and a small proportion of plants may go dormant for a year or more. Peak flowering and fruiting occurs in the summer from May to August, corresponding with increased rainfall during these months in the Florida Keys. Mature seedpods may contain 1 to 10 seeds
summarized below.
Life History and Reproduction: Chamaecrista lineata var. keyensis is a perennial, but some stems will die back every year, and a small proportion of plants may go dormant for a year or more. Peak flowering and fruiting occurs in the summer from May to August, corresponding with increased rainfall during these months in the Florida Keys. Mature seedpods may contain 1 to 10 seeds. Seedlings may appear throughout the year, with a peak in the fall during September to October, immediately following seed dispersal. Seeds may persist in the soil seed bank for up to 3 years (Liu and Menges 2005, p. 1484).
Chamaecrista lineata var. keyensis flowers require insect visitation for pollination. The anthers (pollen-bearing structures) have small pores from which pollen escapes when a visiting insect's wings vibrate the structure, a phenomenon known as buzz-pollination. Though many types of insects visit C. lineata var. keyensis flowers, effective pollination can be performed only by buzz-pollinating bees. Of the numerous bee species that visit the flowers, only Xylocopa micans and Melissodes spp. bees have been observed performing effective buzz-pollination (Liu and Koptur 2003, pp. 1184-1186).
Chamaecrista lineata var. keyensis flowers are self-compatible (an individual can be fertilized with its own pollen), and seeds are generated both by self- and cross-pollination. However, seed set is higher when cross-pollination occurs. Seed germination rates are higher from cross-pollinated flowers, suggesting that inbreeding depression occurs in seeds produced through self-pollination (Liu and Koptur 2003, pp. 1184-1186). Taken together, these findings confirm that insect pollination is crucial to the plant's reproduction and progeny fitness.
Fire Ecology and Demography: Chamaecrista lineata var. keyensis grows in the understory of pine rocklands, a fire-dependent ecosystem. The seeds have a hard seed coat that may help them survive fire (Liu et al. 2005a, p. 216)
pollination (Liu and Koptur 2003, pp. 1184-1186). Taken together, these findings confirm that insect pollination is crucial to the plant's reproduction and progeny fitness.
Fire Ecology and Demography: Chamaecrista lineata var. keyensis grows in the understory of pine rocklands, a fire-dependent ecosystem. The seeds have a hard seed coat that may help them survive fire (Liu et al. 2005a, p. 216). Fire has important effects on survival and regeneration of C. lineata var. keyensis. Fire may immediately kill some of the plants, but populations rebound during the first and second years after fire. Three years post-fire, survival in burned areas can equal that of unburned areas, suggesting that C. lineata var. keyensis can recover completely after fire. Fire stimulates stem growth, fruiting, and seedling establishment. Fire seasonality may produce different responses in C. lineata var. keyensis. Overall, winter and early summer fires produce more favorable results compared with late summer fires (Liu and Menges 2005, p. 1848).
Demographic modeling by (Liu et al. 2005a, p. 210) found that fire return intervals of 5 to 7 years generated the lowest extinction and population decline probabilities for Chamaecrista lineata var. keyensis, regardless of burn season. Bradley and Saha (2009, p. 20) found that both fire frequency and time since the last fire had significant effects on the density of C. lineata var. keyensis in study plots. The highest densities were found in plots that were burned three or more times over a 45-year period from 1960 to 2005, and in plots that had burned recently, while lower densities were associated with plots that had not been burned in 45 years.
Liu et al. (2005b, p. 71) found that differences in fire intensity (as measured by maximum ground temperature) did not have a significant long-term effect on survival, growth, or seedling recruitment. However, the number of fruits produced and percentage of fruiting plants increased as fire intensity increased
while lower densities were associated with plots that had not been burned in 45 years.
Liu et al. (2005b, p. 71) found that differences in fire intensity (as measured by maximum ground temperature) did not have a significant long-term effect on survival, growth, or seedling recruitment. However, the number of fruits produced and percentage of fruiting plants increased as fire intensity increased. This suggests that low-intensity fires associated with shorter fire return intervals (less than 3 years) may not provide the most favorable conditions for post-fire recovery.
Taken together, these results indicate that Chamaecrista lineata var. keyensis can tolerate and may benefit from periodic fire. As discussed above under “Habitat,” fire is a crucial element in maintaining the pine rocklands habitat. Periodic fires eliminate the shrub subcanopy, remove litter from the ground, recycle nutrients, and are necessary to prevent succession to a hardwood-dominated ecosystem (rockland hammock) that is unsuitable for C. lineata var. keyensis (Bradley and Gann 1999, pp. 17-18).
Chamaesyce deltoidea ssp. serpyllum (wedge spurge)
Species Description
Chamaesyce deltoidea ssp. serpyllum is a small, prostrate, perennial herb. The stems are slender and numerous, radiating out from the taproot. The leaves are 2 to 5 mm (0.08 to 0.19 in) long, more or less triangular, and covered with fine short fuzz, giving the plant a silvery appearance. The flowers are cyathia, the specialized inflorescences characteristic of the genus Euphorbia and its close relatives. The fruit is a capsule about 1.5 mm (0.06 in) wide (Small 1933, p. 795; Herndon 1993, p. 50).
Taxonomy
John K. Small collected plants on Big Pine Key and first described Chamaesyce deltoidea ssp. serpyllum as C. serpyllum (Small 1913, p. 81). Burch (1966, p.99) included C. serpyllum as a subspecies of C. deltoidea, assigning the currently accepted name C. deltoidea ssp. serpyllum. The online Atlas of Florida Vascular Plants uses the name C. deltoidea ssp
, p. 795; Herndon 1993, p. 50).
Taxonomy
John K. Small collected plants on Big Pine Key and first described Chamaesyce deltoidea ssp. serpyllum as C. serpyllum (Small 1913, p. 81). Burch (1966, p.99) included C. serpyllum as a subspecies of C. deltoidea, assigning the currently accepted name C. deltoidea ssp. serpyllum. The online Atlas of Florida Vascular Plants uses the name C. deltoidea ssp. serpyllum (Wunderlin and Hansen 2008, p. 1), and the Integrated Taxonomic Information System (ITIS 2015, p. 1) indicates that its taxonomic status is accepted. We have carefully reviewed all taxonomic data to determine that Chamaesyce deltoidea (Engelm. ex Chapm.) Small ssp. serpyllum (Small) D.G. Burch is a valid taxon. Synonyms include Chamaesyce serpyllum Small; Euphorbia deltoidea Engelmann ex Chapman ssp. serpyllum (Small) Y. Yang; and Chamaesyce serpyllum Small, Euphorbia deltoidea Engelmann ex Chapman var. serpyllum (Small) Oudejans (Wunderlin and Hansen 2008, p. 3).
Climate
The climate of south Florida where Chamaesyce deltoidea ssp. serpyllum occurs is classified as tropical savanna, as described above for Chamaecrista lineata var. keyensis .
Habitat
Chamaesyce deltoidea ssp. serpyllum occurs in pine rocklands and adjacent disturbed sites on Big Pine Key, including roadsides. It most often grows directly from crevices in the oolitic limestone substrate (Bradley and Gann 1999, p. 31). Pine rocklands are described in detail for Chamaecrista lineata var. keyensis, above. Within pine rocklands, Chamaesyce deltoidea ssp. serpyllum is associated with areas of relatively higher elevation, extensive exposed rock substrate, where the understory is open, hardwood and palm density is low, and native herbaceous species cover and richness are high (Bradley and Saha 2009, p. 26; Ross and Ruiz 1996, p. 6; Bradley 2006, p. 27). Roadsides dominated mostly by native herbs and grasses where exotic lawn grasses are not established are a potentially important habitat for C. deltoidea ssp. serpyllum (Bradley 2006, p. 37)
bstrate, where the understory is open, hardwood and palm density is low, and native herbaceous species cover and richness are high (Bradley and Saha 2009, p. 26; Ross and Ruiz 1996, p. 6; Bradley 2006, p. 27). Roadsides dominated mostly by native herbs and grasses where exotic lawn grasses are not established are a potentially important habitat for C. deltoidea ssp. serpyllum (Bradley 2006, p. 37).
Historical Range
Chamaesyce deltoidea ssp. serpyllum is historically known from only Big Pine Key in the Florida Keys in Monroe County, Florida.
Current Range, Population Estimates, and Status
The current range of Chamaesyce deltoidea ssp. serpyllum is on Big Pine Key. Small groups of plants are scattered widely across the island (Herndon 1993, in Bradley and Gann 1999, p. 31).
Population data for Chamaesyce deltoidea ssp. serpyllum have been collected on Big Pine Key periodically since 1996. Indicators show that the population on Big Pine Key has declined over the past 19 years. Using study plots across Big Pine Key, Ross and Ruiz (1996, p. 6) found C. deltoidea ssp. serpyllum was present in 22 percent of study plots in 1996. When sampled again by Bradley (2006, p. 11; Bradley et al. 2015, p. 21) in 2005, 2007, and 2013, the species was present in 7.4, 5.5, and 3.7 percent of study plots, respectively. This represents an 83 percent reduction of the species' frequency in study plots from 1996 to 2013, and a 50 percent reduction from 2005 to 2013. The decrease in frequency is attributed in large part to the total disappearance of the species from study plots in the southern portion of Big Pine Key after Hurricane Wilma in 2005 (Bradley et al. 2013, p. 24).
Total population size for Chamaesyce deltoidea ssp. serpyllum on publicly owned pine rocklands on Big Pine Key (478 ha (1,181 acres)) was estimated to be 352,993 plants in 2005 (pre-Hurricane Wilma), 343,255 in 2007 (post-Wilma), and 368,557 in 2013
al disappearance of the species from study plots in the southern portion of Big Pine Key after Hurricane Wilma in 2005 (Bradley et al. 2013, p. 24).
Total population size for Chamaesyce deltoidea ssp. serpyllum on publicly owned pine rocklands on Big Pine Key (478 ha (1,181 acres)) was estimated to be 352,993 plants in 2005 (pre-Hurricane Wilma), 343,255 in 2007 (post-Wilma), and 368,557 in 2013. This represents a slight (4.4 percent) increase in the known population size of from 2005 to 2013 (Bradley et al. 2013, p. 21). The slight increase in 2013 is due to the Blue Hole Fire in 2011. Prior to this fire, the species had not been detected in plots in the Blue Hole area of Big Pine Key, but was found in one plot after the 2011 fire. This single plot contained 134 plants, 17.3 percent of the plants recorded across all 646 plots in 2013. If this single plot is taken out of the analysis, density per plot would be 1.3, 10.3 percent lower than that recorded in 2005, and 18.6 percent lower than 2007 (Bradley et al. 2015, pp. 24-25; Bradley and Saha 2009, p. 12). Since 82 percent of the pine rocklands on Big Pine Key are publicly owned, this estimate likely accounts for the majority of the population. Taken together, the data suggest that the population declined significantly due to Hurricane Wilma but rebounded by 2013. However, the frequency of the plant in study plots has decreased from 1996 to 2013, suggesting that fewer areas now support the species. While there have been significant changes between sampling events, the 9-year pattern of total population size is stable (Bradley et al. 2015, pp. 21, 24, 49). At the same time, there has been a reduction in the species' range on Big Pine Key and frequency of the plant in study plots (Bradley et al. 2015, pp. 25, 49), suggesting that while there has been a small increase in the total number of plants, the area occupied by the plant is shrinking.
Table 2 summarizes the status and trends of the known occurrences of Chamaesyce deltoidea ssp. serpyllum
9). At the same time, there has been a reduction in the species' range on Big Pine Key and frequency of the plant in study plots (Bradley et al. 2015, pp. 25, 49), suggesting that while there has been a small increase in the total number of plants, the area occupied by the plant is shrinking.
Table 2 summarizes the status and trends of the known occurrences of Chamaesyce deltoidea ssp. serpyllum.
Table 2—Summary of the Status and Trends of the Known Occurrences of Chamaesyce deltoidea ssp. serpyllum Population Ownership Most recent population estimate Status Trend Big Pine Key USFWS, FWC, private 368,557 1 Extant 1 Declining. 1 1 Bradley et al. 2015, pp. 24-25. Biology
Life History and Reproduction: Reproduction is sexual, and the plant produces seeds. No studies of reproductive biology or ecology have been conducted for Chamaesyce deltoidea ssp. serpyllum. Other species of Chamaesyce are completely reliant on insects for pollination and seed production, while others are capable of self-pollination. Pollinators may include bees, flies, ants, and wasps (Ehrenfeld 1976, pp. 406, 95-97).
Fire Ecology and Demography: The assemblage of endemic plants of the pine rocklands, which includes Chamaesyce deltoidea ssp. serpyllum, tends to be shade-intolerant and benefits from periodic burning to reduce competition from woody vegetation e.g., shading, leaf litter accumulation) (Carlson et al. 1993, p. 922; Liu et al. 2005a, p. 210, Liu et al. 2005b, p. 71). C. deltoidea ssp. serpyllum is found more frequently in recently burned areas (Slapcinsky et al. 2010, p. 11). Populations of C. deltoidea ssp. serpyllum may decline without periodic fires, and fire has been shown to stimulate significant population growth (Slapcinsky and Gordon 2007, p. 5).
Linum arenicola (sand flax)
Species Description
Linum arenicola is a small, perennial herb that is 35 to 53 cm (14 to 21 in) tall with yellow flowers that are similar in appearance those of a buttercup ( Ranunculus spp.)
ons of C. deltoidea ssp. serpyllum may decline without periodic fires, and fire has been shown to stimulate significant population growth (Slapcinsky and Gordon 2007, p. 5).
Linum arenicola (sand flax)
Species Description
Linum arenicola is a small, perennial herb that is 35 to 53 cm (14 to 21 in) tall with yellow flowers that are similar in appearance those of a buttercup ( Ranunculus spp.). When not in flower, it resembles a short, wiry grass. Plants have one to several stems arising from their base. Leaves are linear in shape, 7-10 millimeters (mm) (0.3-0.4 in) long, 0.6-1 mm (0.02-0.04 in) wide, and arranged alternately along stems, and they have glands scattered along their edges. Flowers are produced on stems consisting of a few slender, spreading branches. The individual flowers are on small stalks 2 mm (0.08 in) long or shorter. The flowers have five yellow, egg-shaped petals that are 4.5-5.5 mm (0.18-0.22 in) long, and five green, lance-shaped to egg-shaped sepals that are 2.4-3.2 mm (0.09-0.13 in) long. The fruit is a woody capsule, 2.1-2.5 mm (0.08-0.1 in) long, 2-2.3 mm (0.08-0.09 in) diameter, which dries and splits into 10 segments. The seeds are ovate, 1.2-1.4 mm (0.05-0.06 in) long, and 0.7- 0.8 mm (0.027-0.031 in) wide (Rogers 1963, pp. 103-104).
Taxonomy
Linum arenicola was first described by Small in 1907 as Cathartolinum arenicola from plants he collected in Miami-Dade County in 1904. This treatment was consistently followed by Small (1913a, p. 69; 1913b, p. 96; 1933, p. 752). In 1931, Winkler included Cathartolinum within the genus Linum, renaming the plants Linum arenicola (Winkler 1931, p. 30). Others have followed this treatment, including Rogers (1963, p. 103), Long and Lakela (1971, p. 505), Robertson (1971, p. 649), Wunderlin (1998, p. 100), and Wunderlin & Hansen (2003, p. 100) (Hodges and Bradley 2006, p. 37).
Synonyms include Cathartolinum arenicola Small (Wunderlin and Hansen 2004, p. 5). The Integrated Taxonomic Information System (2015, p
inum arenicola (Winkler 1931, p. 30). Others have followed this treatment, including Rogers (1963, p. 103), Long and Lakela (1971, p. 505), Robertson (1971, p. 649), Wunderlin (1998, p. 100), and Wunderlin & Hansen (2003, p. 100) (Hodges and Bradley 2006, p. 37).
Synonyms include Cathartolinum arenicola Small (Wunderlin and Hansen 2004, p. 5). The Integrated Taxonomic Information System (2015, p. 1) uses the name Linum arenicola and indicates that this species' taxonomic standing is accepted. The online Atlas of Florida Vascular Plants (Wunderlin and Hansen 2008, p. 1) uses the name L. arenicola. There is consensus that L. arenicola is a distinct taxon. We have carefully reviewed the available taxonomic information to reach the conclusion that the species is a valid taxon.
Climate
The climate of south Florida where Linum arenicola occurs is classified as tropical savanna, as described above for Chamaecrista lineata var. keyensis and Chamaesyce deltoidea ssp. serpyllum .
Rainfall within the range of Linum arenicola varies from an annual average of 153-165 cm (60-65 in) in the northern portion of the Miami Rock Ridge to an average of 89-102 cm (35-40 in) in the lower Florida Keys (Snyder et al. 1990, p. 238).
Habitat
Pine Rockland s: Linum arenicola occurs in pine rocklands, disturbed pine rocklands, dry marl prairie, and disturbed areas on rocky soils adjacent to these habitats (Bradley and Gann 1999, p. 61; Hodges and Bradley 2006, p. 37). L. arenicola grows in thin soil over limestone or in small soil patches caught in surface irregularities of exposed limestone (Kernan and Bradley, 1996, p. 2). Sites most likely to support L. arenicola have a grass- and herb-dominated understory, abundant pine regeneration, and high cover of exposed rock (Ross and Ruiz 1996, pp. 5-6). The pine rocklands and marl prairies where this species occurs require periodic fire to maintain an open, shrub-free subcanopy, and to reduce litter levels (Bradley and Saha 2009, p. 4)
one (Kernan and Bradley, 1996, p. 2). Sites most likely to support L. arenicola have a grass- and herb-dominated understory, abundant pine regeneration, and high cover of exposed rock (Ross and Ruiz 1996, pp. 5-6). The pine rocklands and marl prairies where this species occurs require periodic fire to maintain an open, shrub-free subcanopy, and to reduce litter levels (Bradley and Saha 2009, p. 4). Pine rocklands habitat is described in detail for Chamaecrista lineata var. keyensis, above.
Roadsides and Other Disturbed Sites: While pine rocklands historically were the primary habitat of Linum arenicola, the species is currently rare in relatively undisturbed pine rocklands, with the exception of plants on Big Pine Key. Several occurrences are in scraped (scarified) pine rocklands remnants that are dominated by native pine rocklands species, but have little or no pine canopy or subcanopy (Bradley and Van Der Heiden 2013, pp. 9-12). Two populations in Miami-Dade County occur entirely on levees composed of crushed oolitic limestone that are surrounded by sawgrass marsh (Bradley and Gann 1999, p. 61; Bradley and Van Der Heiden 2013, pp. 7-9). Roadsides and other disturbed sites are important habitat for L. arenicola because they imitate upland herbaceous habitat (Hodges and Bradley 2006, p. 40). The most robust roadside populations occur in areas adjacent to pine rocklands or rockland hammocks (Hodges 2010, p. 3). Where L. arenicola is found on roadsides, the ground cover is dominated mostly by native herbs and grasses where exotic lawn grasses have not been planted (Bradley 2006, p. 37). Infrequent mowing of some roadsides, and of disturbed sites such as Homestead Air Reserve Base (HARB) and U.S. Special Operations Command South Headquarters (SOCSOUTH), a unified command of all four services in the Department of Defense (DOD) has likely allowed the species to persist by preventing these sites from being taken over by hardwoods
n grasses have not been planted (Bradley 2006, p. 37). Infrequent mowing of some roadsides, and of disturbed sites such as Homestead Air Reserve Base (HARB) and U.S. Special Operations Command South Headquarters (SOCSOUTH), a unified command of all four services in the Department of Defense (DOD) has likely allowed the species to persist by preventing these sites from being taken over by hardwoods.
Because Linum arenicola seems to only rarely occur within intact pine rocklands, but more frequently adjacent to this habitat, developing conservation and management plans for this species is exceptionally difficult. Its persistence on roadsides is not fully understood. L. arenicola was at one time more common in pine rocklands in Miami-Dade County, but a lack of periodic fires in most pine rocklands fragments over the last century have pushed this species into more sunny, artificial environments (Bradley and Gann 1999, p. 61). It is also possible that the species has evolved to persist along roadsides as fire regimes and natural areas were altered and destroyed over the last century (Hodges and Bradley 2006, p. 41).
Dry Marl Prairie: Marl prairie is a sparsely vegetated, grass-dominated community found on marl substrates in South Florida. Marls are fine, white, calcareous muds formed from calcite precipitated by a mixture of green algae, blue green algae, and diatoms, known as periphyton. It is seasonally inundated (2 to 4 months) to a shallow depth averaging about 20 cm (8 in). Marl prairie is a diverse community that may contain over 100 species. Marl prairie normally dries out during the winter and is subject to fires at the end of the dry season (FNAI 2010, p. 1). Occurrences reported from marl prairie are at sites that have been artificially drained (Bradley and Van Der Heiden 2013, p. 11), or are scraped pine rocklands that function more like marl prairie (Kernan and Bradley 1996, p. 11)
rse community that may contain over 100 species. Marl prairie normally dries out during the winter and is subject to fires at the end of the dry season (FNAI 2010, p. 1). Occurrences reported from marl prairie are at sites that have been artificially drained (Bradley and Van Der Heiden 2013, p. 11), or are scraped pine rocklands that function more like marl prairie (Kernan and Bradley 1996, p. 11). As with roadside populations of Linum arenicola, it is possible that dry marl prairies have become refugia for the species as fire regimes and natural areas were altered and destroyed over the last century. Accordingly, the Service does not consider marl prairie to be a primary habitat for L. arenicola .
Historical Range
The historical range of Linum arenicola consists of central and southern Miami-Dade County and
Current Range, Population Estimates, and Status
The current range of Linum arenicola consists of eight extant populations in Miami-Dade County and four extant populations in the Florida Keys (see Table 3, below). In Miami-Dade County, the current distribution of Linum arenicola is from just north of SW 184 Street (in the Richmond Pinelands), south to the intersection of Card Sound Road and the C-102 canal, and west to SW 264 Street and 177 Avenue (Everglades Archery Range at Camp Owaissa Bauer). This distance is approximately 30 km (19 mi) north to south, and 14 km (9 mi) east to west. In the Florida Keys (Monroe County), the current distribution of L. arenicola includes four islands: Big Pine Key, Upper and Lower Sugarloaf Keys, and Big Torch Key.
Multiple surveys have been conducted for Linum arenicola in Miami-Dade and Monroe Counties over the past 30 years. However, most surveys only cover one county and not the other. The large area of potential habitat and scarcity and diminutive size of L. arenicola make thorough surveys for this species difficult (Hodges and Bradley 2006, p. 37)
y, Upper and Lower Sugarloaf Keys, and Big Torch Key.
Multiple surveys have been conducted for Linum arenicola in Miami-Dade and Monroe Counties over the past 30 years. However, most surveys only cover one county and not the other. The large area of potential habitat and scarcity and diminutive size of L. arenicola make thorough surveys for this species difficult (Hodges and Bradley 2006, p. 37).
Based on a compilation of all survey work through 2013, including Austin (1980), Kernan and Bradley (1996, pp.1-30), Bradley and Gann (1999, pp. 61-65), Hodges and Bradley (2006, pp. 37-41), Bradley and Saha (2009, p. 10), Bradley (2009, p. 3), Hodges (2010, pp. 4-5, 15), Bradley and van der Heiden (2013, pp. 6-12,19), and Bradley et al. (2015, pp. 28-29), of 26 historical population records for Linum arenicola, 12 populations are extant and 14 are extirpated (see Table 3), a loss of roughly 54 percent of known populations, from the early 1900s to the present.
Table 3 summarizes the status and trends of the known occurrences of Linum arenicola .
Table 3—Summary of the Status and Trends of the Known Occurrences of Linum arenicola Population Ownership Most recent population estimate County Trend Extant 12 records Big Pine Key USFWS, FWC, TNC 12 , Private 2,676 (2007) 1 Monroe declining. Upper Sugarloaf Key FDOT 13 , USFWS 73 (2010) 2 Monroe insufficient data. Lower Sugarloaf Key FDOT 13 , USFWS 531 (2010) 2 Monroe stable. Big Torch Key FDOT 13 , Private 1 (2010) 2 Monroe declining. Richmond Pineland Private 56 (2014) 5 Miami-Dade insufficient data. Martinez Pineland Miami-Dade County 100-200 (2013) 6 Miami-Dade insufficient data. Everglades Archery Range (Camp Owaissa Bauer) Miami-Dade County 23 (2012) 7 Miami-Dade insufficient data. HAFB 15 1—S of Naizare BLVD DOD 14 , Miami-Dade County 24,000 (2013) 7 Miami-Dade stable. SOCSOUTH (HAFB 2—NW side of Bikini BLVD) DOD 14 (leased from Miami-Dade County) 74,000 (2009) 7 10 Miami-Dade stable. HARB (SW 288 St
eland Miami-Dade County 100-200 (2013) 6 Miami-Dade insufficient data. Everglades Archery Range (Camp Owaissa Bauer) Miami-Dade County 23 (2012) 7 Miami-Dade insufficient data. HAFB 15 1—S of Naizare BLVD DOD 14 , Miami-Dade County 24,000 (2013) 7 Miami-Dade stable. SOCSOUTH (HAFB 2—NW side of Bikini BLVD) DOD 14 (leased from Miami-Dade County) 74,000 (2009) 7 10 Miami-Dade stable. HARB (SW 288 St. and 132 Ave) DOD 14 37 (2011) 7 Miami-Dade insufficient data. C-102 Canal SW 248 St. to U.S. 1 SFWMD 11 1,000-10,000 (2013) 7 Miami-Dade insufficient data. L-31E canal, from SW 328 St. to Card Sound Road SFWMD 11 Plants occur along 14 km (8.7 mi) of levee (2013) 7 Miami-Dade insufficient data. Extirpated 14 records Middle Torch Key FWC, FDOT 13 3 (2005) 3 Monroe Ramrod Key FDOT 13 110 (1979) 4 Monroe Park Key FDOT 13 unknown (1961) 3 Monroe Boca Chica DOD 14 , other (unknown) unknown (1912) 3 Monroe Camp Jackson unknown unknown (1907) 9 Miami-Dade Big Hammock Prairie unknown unknown (1911) 9 Miami-Dade Camp Owaissa Bauer Miami-Dade County 10 (1983) 7 Miami-Dade Allapatah Drive and Old Cutler Road Private 256 (1996) 8 Miami-Dade Bauer Drive (Country Ridge Estates) Miami-Dade County 8 (1996) 8 Miami-Dade Silver Green Cemetery Private 47 (1996) 8 Miami-Dade Palmetto Bay Village Center Private 12 (1996) 8 Miami-Dade HAFB (Community Partnership Drive) DOD 14 , Miami-Dade County unknown (2010) 7 Miami-Dade Coco Plum Circle (corner of Robles Street & Vista Mar Street) Private 75 (1996) 8 Miami-Dade George Avery Pineland Preserve Private “small colony” (2002) 7 Miami-Dade 1 Bradley and Saha 2009, p. 10 2 Hodges 2010, p. 10 3 Hodges and Bradley 2006, pp. 39-48 4 Austin et al. 1980 in FNAI 5 FTBG 2014, p. 2 6 Possely 2014, pers. comm. 7 Bradley and Van Der Heiden 2013, pp. 6-11 8 Kernan and Bradley 1996, p. 9 9 Bradley and Gann 1999, p. 65 10 Bradley 2009, p
reet) Private 75 (1996) 8 Miami-Dade George Avery Pineland Preserve Private “small colony” (2002) 7 Miami-Dade 1 Bradley and Saha 2009, p. 10 2 Hodges 2010, p. 10 3 Hodges and Bradley 2006, pp. 39-48 4 Austin et al. 1980 in FNAI 5 FTBG 2014, p. 2 6 Possely 2014, pers. comm. 7 Bradley and Van Der Heiden 2013, pp. 6-11 8 Kernan and Bradley 1996, p. 9 9 Bradley and Gann 1999, p. 65 10 Bradley 2009, p. 3 11 South Florida Water Management District (SFWMD) 12 The Nature Conservancy (TNC) 13 Florida Department of Transportation (FDOT) 14 Department of Defense (DOD) 15 Homestead Air Force Base (HAFB; decommissioned) Based on the data presented in Table 3, reliable population trends can be derived from past surveys for 5 of the 12 extant populations. Populations on Big Pine Key and Big Torch Key have shown clear declines. Three populations appear to be stable (data suggest they have not declined appreciably). Data are insufficient to determine trends for the remaining seven populations. The data also show that 5 of the 12 extant populations are rather small, having fewer than 100 plants.
Miami-Dade County: The first survey for Linum arenicola, conducted in 1980 in Miami-Dade County, reported two extant and eight extirpated populations, but population sizes were not reported (Austin et al., 1980, p. 3). A 1996 survey conducted in Miami-Dade County reported seven populations, representing about 1,000 plants (Kernan and Bradley 1996, p. 5). A 1999 status survey reported five extant populations and seven extirpated populations in Miami-Dade County (Bradley and Gann 1999, p. 65).
A comprehensive field survey of Linum arenicola sites in Miami-Dade was conducted in 2013 (Bradley and van der Heiden 2013, p. 4). L. arenicola populations were found at six sites, containing an estimated total of 107,060 plants. Populations ranged in size from 23 plants to 74,000 plants, with a median population size of approximately 4,500. All but one of the Miami-Dade L
and Gann 1999, p. 65).
A comprehensive field survey of Linum arenicola sites in Miami-Dade was conducted in 2013 (Bradley and van der Heiden 2013, p. 4). L. arenicola populations were found at six sites, containing an estimated total of 107,060 plants. Populations ranged in size from 23 plants to 74,000 plants, with a median population size of approximately 4,500. All but one of the Miami-Dade L. arenicola populations occur on public lands, but only the Martinez Pineland site is managed for conservation. The remaining sites are owned by the DOD (military bases), State of Florida (canal banks; SFWMD), and Miami-Dade County (a public archery range). A seventh small population located in 2014 at the Richmond pinelands is located on private land that is currently slated for development (Fairchild Tropical Botanic Garden (FTBG) 2014, p. 2). The largest Linum arenicola population in Miami-Dade County, estimated at 74,000 plants in 2009 (Bradley 2009, p. 3), is located on property owned by the Miami-Dade County Homeless Trust and leased to Special Operations Command South (SOCSOUTH; a DOD facility).
In Miami-Dade County, of 18 records for Linum arenicola, 8 populations are extant, while 10 are extirpated, a loss of roughly 56 percent of known populations. The loss of these populations corresponds to a contraction of the species' historical range in Miami-Dade County by approximately 20 km (12 mi) at its northern extent (40 percent reduction in north to south range), and approximately 15 km (9 mi) of its east to west extent (50 percent reduction in east to west range).
Monroe County (Florida Keys): A 1999 status survey reported four Linum arenicola populations in Monroe County (Bradley and Gann 1999, p. 65). In 2006, Hodges and Bradley (2006, pp. 37-41) conducted the first comprehensive survey of the distribution and abundance of L. arenicola in the Florida Keys, including extant occurrences, historical records, and exploratory surveys of potential habitat
e).
Monroe County (Florida Keys): A 1999 status survey reported four Linum arenicola populations in Monroe County (Bradley and Gann 1999, p. 65). In 2006, Hodges and Bradley (2006, pp. 37-41) conducted the first comprehensive survey of the distribution and abundance of L. arenicola in the Florida Keys, including extant occurrences, historical records, and exploratory surveys of potential habitat. Four extant populations were observed (Big Pine Key, Big Torch Key, Middle Torch Key, and Lower Sugarloaf Key) and three historical populations were confirmed extirpated (Boca Chica Key, Ramrod Key, and Park Key). The surveys did not find L. arenicola in potential habitat on No Name Key, Little Torch Key, or Upper Sugarloaf Key (Hodges and Bradley 2006, pp. 37, 48). However, in 2010, Hodges (2010, p. 10) resurveyed Upper Sugarloaf and rediscovered the population.
Linum arenicola is extirpated from 4 of 8 (50 percent) of the islands that once supported it. Its historical range spanned approximately 36 km (22 mi) from northeast to southwest. The loss of populations on Boca Chica, Park, Middle Torch, and Ramrod Keys represents a 14-km (9-mi) loss of the western extent of the species' range, corresponding to a 39 percent contraction of the species' historical range.
The total population of Linum arenicola in Monroe County is estimated at 2,676 plants in pine rocklands on Big Pine Key (Bradley and Saha 2009, p. 10), and 100 to 1,000 plants across the remainder of the Florida Keys (Hodges and Bradley 2006, pp. 37, 48; Hodges 2010, p. 10).
The largest population in Monroe County is located on Big Pine Key within the National Key Deer Refuge (NKDR) and surrounding lands, where there are approximately 478 ha (1,181 ac) of publicly owned pine rocklands (Gann et al. 2002, p. 806; Bradley 2006, p. 4; Hodges and Bradley 2006, pp. 37-38). It is also the best studied population
ys (Hodges and Bradley 2006, pp. 37, 48; Hodges 2010, p. 10).
The largest population in Monroe County is located on Big Pine Key within the National Key Deer Refuge (NKDR) and surrounding lands, where there are approximately 478 ha (1,181 ac) of publicly owned pine rocklands (Gann et al. 2002, p. 806; Bradley 2006, p. 4; Hodges and Bradley 2006, pp. 37-38). It is also the best studied population. On Big Pine Key, Linum arenicola occurs at the Terrestris Preserve, which is owned by TNC; this occurrence is included within the Big Pine Key site in Table 3.
Linum arenicola on Big Pine Key has been surveyed multiple times since 1996, with the most recent being 2014. Because of the size of Big Pine Key, sample study plots were utilized for these surveys, as opposed to a complete search of all potential habitats. Ross and Ruiz (1996, p. 5) found the species in 11 percent of their study plots. Subsequent surveys in 2005, 2007, and 2013 have found L. arenicola to be extremely rare, being recorded in 4.1, 2.0, and 1.4 et al. 2015, pp. 28-29).
The decline in the Big Pine Key population of Linum arenicola from 2005 to 2007 can be largely attributed to the effects of Hurricane Wilma (Bradley 2006, p. 11; Hodges 2010, p. 4). Prior to Wilma, there was a maximum of 56,404 individuals of L. arenicola in the 478 ha (1,181 ac) of publicly owned pine rocklands on Big Pine Key (Bradley 2006, p. 19). As of 2007, there were just 2,676 plants, representing a 95 percent decline (Bradley and Saha 2009, p. 10). Significantly, the species virtually disappeared from the southern half of Big Pine Key after Hurricane Wilma (Bradley and Saha 2009, p. 10).
Historically, the population has declined due to habitat loss and fire suppression. Approximately half of the historical pine rocklands on Big Pine Key have been lost (Bradley 2006, p. 35)
, representing a 95 percent decline (Bradley and Saha 2009, p. 10). Significantly, the species virtually disappeared from the southern half of Big Pine Key after Hurricane Wilma (Bradley and Saha 2009, p. 10).
Historically, the population has declined due to habitat loss and fire suppression. Approximately half of the historical pine rocklands on Big Pine Key have been lost (Bradley 2006, p. 35). Long-term ecological changes associated with fire suppression, land clearing, SLR, changes in hydrology, fluctuations in Key deer ( Odocoileus virginianus clavium ) densities, and invasion of exotic plants likely have impacted the population sizes of this species (Bradley 2006, p. 2; Bradley and Saha 2009, p. 2).
The population on Big Torch Key also declined after Hurricane Wilma, but this decline may have been due to herbicide applications or frequent mowing associated with road shoulder maintenance (Hodges 2010, p. 4).
Biology
Life History and Reproduction: Little is known about the life history of Linum arenicola, including pollination biology, seed production, or dispersal. Reproduction is sexual, with new plants generated from seeds. The species produces flowers from February to September, with a peak around March and April. L. arenicola population demographics or longevity have not been studied (Bradley and Gann, 1999, p. 65; Hodges and Bradley 2006, p. 41; Hodges 2007, p. 2).
Fire Ecology and Demography: There have been no studies of Linum arenicola population demographics or relationship to fire, though historical declines have been partially attributed to habitat loss from fire suppression or inadequate fire management.
Argythamnia blodgettii (Blodgett's silverbush)
Species Description
Argythamnia blodgettii, in the Euphorbia family, is an erect, perennial shrub or herb, 10 to 60 cm (4 to 24 in) tall, with a woody base and small, green flowers. The stems and leaves are covered with small hairs
orical declines have been partially attributed to habitat loss from fire suppression or inadequate fire management.
Argythamnia blodgettii (Blodgett's silverbush)
Species Description
Argythamnia blodgettii, in the Euphorbia family, is an erect, perennial shrub or herb, 10 to 60 cm (4 to 24 in) tall, with a woody base and small, green flowers. The stems and leaves are covered with small hairs. The leaves, arranged alternately along the stems, are 1.5 to 4.0 cm (0.6 to 1.6 in) long, have smooth (or rarely toothed) edges, are oval or elliptic in shape, and often are colored a distinctive, metallic bluish green. The plants have separate male and female flowers. Staminate (male) flowers have a calyx 7 to 8 mm (0.27 to 0.31 in) wide, consisting of 4 to 5 lance-shaped sepals that are larger than the petals. The petals are broadly elliptic and shorter than the sepals. There are 10 stamens. Pistillate (female) flowers have 4 to 5 sepals that are 5 to 6 mm (0.19 to 0.24 in) long, lance-shaped, and often more narrow than those of male flowers. The petals are broadly elliptic, shorter than the sepals. The fruit is a woody capsule 4 to 5 mm (0.16 to 0.19 in) wide, which contains the seeds (Adapted from Small 1933, pp. 784-785; Bradley and Gann 1999, p. 2).
Taxonomy
Botanist John Torrey first described the species in Chapman (1884, p. 100) as Aphora blodgettii, reporting it for South Florida. In an 1896 (p. 100) revision of the genus, Pax placed it in the genus Ditaxis. In 1897 (p. 100), Chapman placed it in the genus Argythamnia. In 1903, Small placed it again in the genus Ditaxis. In 1914, Pax (p. 100) placed it in synonymy under Ditaxis fendleri, a plant of Colombia, Venezuela, Curacao, and Trinidad. Small (1933, pp. 784-785) retained it as Ditaxis blodgettii, treating it as a southern Florida endemic. Subsequent authors (Webster 1967, p. 100; Long and Lakela 1971, p. 558; Wunderlin 1998, p. 100; Wunderlin and Hansen 2003, p
903, Small placed it again in the genus Ditaxis. In 1914, Pax (p. 100) placed it in synonymy under Ditaxis fendleri, a plant of Colombia, Venezuela, Curacao, and Trinidad. Small (1933, pp. 784-785) retained it as Ditaxis blodgettii, treating it as a southern Florida endemic. Subsequent authors (Webster 1967, p. 100; Long and Lakela 1971, p. 558; Wunderlin 1998, p. 100; Wunderlin and Hansen 2003, p. 100) have retained it as a southern Florida endemic Argythamnia blodgettii (from Hodges and Bradley 2006, p. 10).
The Integrated Taxonomic Information System (2015, p. 1) uses the name Argythamnia blodgettii and indicates that this species' taxonomic standing is accepted. The online Atlas of Florida Vascular Plants (Wunderlin and Hansen 2008, p. 1) uses the name A. blodgettii. In summary, there is consensus that A. blodgettii is a distinct taxon. We have carefully reviewed the available taxonomic information to reach the conclusion that the species is a valid taxon. Synonyms include Aphora blodgettii Torr. ex Chapm.; Ditaxis blodgettii (Torr. ex Chapm.) Pax; Argyrothamnia blodgettii (Torr. ex Chapm.) Chapm.; and Ditaxis fendleri Pax, not (Müll. Arg.) Pax and K. Hoof.
Climate
The climate of south Florida where Argythamnia blodgettii occurs is classified as tropical savanna, as described above for Chamaecrista lineata var. keyensis, Chamaesyce deltoidea ssp. serpyllum, and Linum arenicola.
Rainfall within the range of Argythamnia blodgettii varies from an annual average of 153-165 cm (60-65 in) in the northern portion of the Miami Rock Ridge to an average of 89-102 cm (35-40 in) in the lower Florida Keys (Snyder et al. 1990, p. 238).
Habitat
Argythamnia blodgettii grows in pine rocklands, in sunny gaps or edges of rockland hammock and coastal berm, and on roadsides (Bradley and Gann 1999, p. 3). It grows from crevices on oolitic limestone or on sand. The pine rocklands habitat where it occurs requires periodic fire to maintain an open, sunny understory with a minimum amount of hardwoods
a Keys (Snyder et al. 1990, p. 238).
Habitat
Argythamnia blodgettii grows in pine rocklands, in sunny gaps or edges of rockland hammock and coastal berm, and on roadsides (Bradley and Gann 1999, p. 3). It grows from crevices on oolitic limestone or on sand. The pine rocklands habitat where it occurs requires periodic fire to maintain an open, sunny understory with a minimum amount of hardwoods. Bradley and Gann (1999, p. 3) indicated that this species does tolerate some degree of human-induced disturbance. It can often be found along disturbed edges of pine rocklands, rockland hammock, and coastal berm, or in completely scarified pine rocklands (Bradley and Gann, 1999, p. 3). Pine rocklands are described in detail for Chamaecrista lineata var. keyensis, above.
Coastal Berm: Coastal berms are landscape features found along low-energy coastlines in south Florida and the Florida Keys. Coastal berm is a short forest or shrub thicket found on long, narrow, storm-deposited ridges of loose sediment formed by a mixture of coarse shell fragments, pieces of coralline algae, and other coastal debris. These ridges parallel the shore and may be found on the seaward edge or landward edge of the mangroves or farther inland depending on the height of the storm surge that formed them. They range in height from 0.30 to 3.05 m (1 to 10 ft). Structure and composition of the vegetation is variable depending on height and time since the last storm event. The most stable berms may share some tree species with rockland hammocks, but generally have a greater proportion of shrubs and herbs. Tree species may include Bursera simaruba (gumbo limbo), Coccoloba uvifera (seagrape), Coccothrinax argentata (silver palm), Guapira discolor (blolly), Drypetes diversifolia (milkbark), Genipa clusiifolia (seven year apple), and Metopium toxiferum (poisonwood)
ent. The most stable berms may share some tree species with rockland hammocks, but generally have a greater proportion of shrubs and herbs. Tree species may include Bursera simaruba (gumbo limbo), Coccoloba uvifera (seagrape), Coccothrinax argentata (silver palm), Guapira discolor (blolly), Drypetes diversifolia (milkbark), Genipa clusiifolia (seven year apple), and Metopium toxiferum (poisonwood). Characteristic tall shrub and short tree Eugenia foetida (Spanish stopper), Ximenia americana (hog plum), Randia aculeata (white indigoberry), Pithecellobium keyense (Florida Keys blackbead), and Sideroxylon celastrinum (saffron plum). Short shrubs and herbs include Hymenocallis latifolia (perfumed spiderlily), Capparis flexuosa (bayleaf capertree), Lantana involucrata (buttonsage), and Rivina humilis (rougeplant). More seaward berms or those more recently affected by storm deposition may support a suite of plants similar to beaches, including shoreline Sesuvium portulacastrum (sea purslane), Distichlis spicata (saltgrass), and Sporobolus virginicus (seashore dropseed), or scattered to dense shrub thickets with Conocarpus erectus (buttonwood ), stunted Avicennia germinans (black mangrove), Rhizophora mangle (red mangrove), Laguncularia racemosa (white mangrove), Suriana maritima (bay cedar), Manilkara jaimiqui (wild dilly), Jacquinia keyensis (joewood), and Borrichia frutescens (bushy seaside oxeye) (Florida Natural Areas Inventory (FNAI) 2010a, p. 1).
Coastal berms are deposited by storm waves along low-energy coasts. Their distance inland depends on the height of the storm surge. Tall berms may be the product of repeated storm deposition. Coastal berms that are deposited far enough inland and remain long-undisturbed may in time succeed to hammock. This is a structurally variable community that may appear in various stages of succession following storm disturbance, from scattered herbaceous beach colonizing plants to a dense stand of tall shrubs (FNAI 2010a, p. 2)
rm surge. Tall berms may be the product of repeated storm deposition. Coastal berms that are deposited far enough inland and remain long-undisturbed may in time succeed to hammock. This is a structurally variable community that may appear in various stages of succession following storm disturbance, from scattered herbaceous beach colonizing plants to a dense stand of tall shrubs (FNAI 2010a, p. 2).
Rockland Hammock: Rockland hammock is a species-rich, tropical hardwood forest on upland sites in areas where limestone is very near the surface and often exposed. The forest floor is largely covered by leaf litter with varying amounts of exposed limestone and has few herbaceous species. Rockland hammocks typically have larger, more mature trees in the interior, while the margins can be almost impenetrable in places with dense growth of smaller shrubs, trees, and vines. Typical canopy and subcanopy species include Bursera simaruba, Lysiloma latisiliquum (false tamarind), Coccoloba diversifolia (pigeon plum), Sideroxylon foetidissimum (false mastic), Ficus aurea (strangler fig), Piscidia piscipula (Jamaican dogwood), Ocotea coriacea (lancewood), Drypetes diversifolia, Simarouba glauca (paradisetree), Sideroxylon salicifolium (willow bustic), Krugiodendron ferreum (black ironwood), Exothea paniculata (inkwood), Metopium toxiferum, and Swietenia mahagoni (West Indies mahogany). Mature hammocks may be open beneath a tall, well-defined canopy and subcanopy. More commonly, in less mature or disturbed hammocks, dense woody vegetation of varying heights from canopy to short shrubs is often present. Species that generally make up the shrub layers within rockland hammock include several species of Eugenia (stoppers), Thrinax morrisii and T
tenia mahagoni (West Indies mahogany). Mature hammocks may be open beneath a tall, well-defined canopy and subcanopy. More commonly, in less mature or disturbed hammocks, dense woody vegetation of varying heights from canopy to short shrubs is often present. Species that generally make up the shrub layers within rockland hammock include several species of Eugenia (stoppers), Thrinax morrisii and T. radiata (thatch palms), Amyris elemifera (sea torchwood), Ardisia escallonioides (marlberry), Psychotria nervosa (wild coffee), Chrysophyllum oliviforme (satinleaf), Sabal palmetto (cabbage palm), Guaiacum sanctum (lignum-vitae), Ximenia americana, Colubrina elliptica (soldierwood), Pithecellobium unguis-cati and Pithecellobium keyense, Coccoloba uvifera, and Colubrina arborescens (greenheart). Vines can be common and include Toxicodendron radicans (eastern poison ivy), Smilax auriculata (earleaf greenbrier), Smilax havanensis (Everglades greenbrier), Parthenocissus quinquefolia (Virginia creeper), Hippocratea volubilis (medicine vine), and Morinda royoc (redgal). The typically sparse short shrub layer may include Zamia pumila (coontie) and Acanthocereus tetragonus (triangle cactus). Herbaceous species are occasionally present and generally sparse in coverage. Characteristic species include Lasiacis divaricata (smallcane), Oplismenus hirtellus (basketgrass), and many species of ferns (FNAI 2010e, p. 1).
Rockland hammock occurs on a thin layer of highly organic soil covering limestone on high ground that does not regularly flood, but it is often dependent upon a high water table to keep humidity levels high. Rockland hammocks are frequently located near wetlands; in the Everglades, they can occur on organic matter that accumulates on top of the underlying limestone; in the Keys, they occur inland from tidal flats (FNAI 2010e, p. 1).
Rockland hammock is susceptible to fire, frost, canopy disruption, and ground water reduction
it is often dependent upon a high water table to keep humidity levels high. Rockland hammocks are frequently located near wetlands; in the Everglades, they can occur on organic matter that accumulates on top of the underlying limestone; in the Keys, they occur inland from tidal flats (FNAI 2010e, p. 1).
Rockland hammock is susceptible to fire, frost, canopy disruption, and ground water reduction. Rockland hammock can be the advanced successional stage of pine rocklands, especially in cases where rockland hammock is adjacent to pine rocklands. In such cases, when fire is excluded from pine rocklands for 15 to 25 years, it can succeed to rockland hammock vegetation. Historically, rockland hammocks in south Florida evolved with fire in the landscape. Fire most often extinguished near the edges when it encountered the hammock's moist microclimate and litter layer. However, rockland hammocks are susceptible to damage from fire during extreme drought or when the water table is lowered. In these cases, fire can cause tree mortality and consume the organic soil layer (FNAI 2010e, p. 2).
Rockland hammocks are also sensitive to the strong winds and storm surge associated with infrequent hurricanes. Canopy damage often occurs, which causes a change in the microclimate of the hammock. Decreased relative humidity and drier soils can leave rockland hammocks more susceptible to fire. Rockland hammock can transition into glades marsh, mangrove swamp, salt marsh, coastal rock barren, pine rocklands, maritime hammock, or marl prairie (FNAI 2010e, p. 2).
The sparsely vegetated edges or interior portions laid open by canopy disruption are the areas of rockland hammock that have light levels sufficient to support Argythamnia blodgettii. However, the dynamic nature of the habitat means that areas not currently open may become open in the future as a result of canopy disruption from hurricanes, while areas currently open may develop more dense canopy over time, eventually rendering that portion of the hammock unsuitable for A
tion are the areas of rockland hammock that have light levels sufficient to support Argythamnia blodgettii. However, the dynamic nature of the habitat means that areas not currently open may become open in the future as a result of canopy disruption from hurricanes, while areas currently open may develop more dense canopy over time, eventually rendering that portion of the hammock unsuitable for A. blodgettii.
Historical Range
Argythamnia blodgettii historically occurred from central and southern Miami-Dade County from Brickell Hammock to Long Pine Key in Everglades National Park, and in Monroe County throughout the Florida Keys from Totten Key south to Key West (Bradley and Gann 1999, p. 2).
Current Range, Population Estimates, and Status
Argythamnia blodgettii is currently known from central Miami-Dade County from Coral Gables and southern Miami-Dade County to Long Pine Key in Everglades National Park, and the Florida Keys from nine islands, from Windley Key (Bradley and Gann 1999, p. 3) southwest to Boca Chica Key (Hodges and Bradley 2006, pp. 10, 43).
Previous status surveys of Argythamnia blodgettii include Bradley and Gann (1999, pp. 2-6) and Hodges and Bradley (2006, pp. 11-20, 43). Bradley and Gann (1999, p. 3) reported 18 extant occurrences of A. blodgettii in 1999 (4 in Monroe County, 14 in Miami-Dade County), representing approximately 10,000 plants. Hodges and Bradley (2006, pp. 11-20, 43) verified that A. blodgettii is extant on nine islands in the Florida Keys A. blodgettii.
Although we do not know the total extent of the former range of Argythamnia blodgettii, approximately 12 miles (19 kilometers) of the species' range has been lost near the northern end of the range in Miami-Dade County and 43 miles (69 kilometers) has been lost in Monroe County on the southern edge of the species' range (Bradley and Gann 1999, p. 3)
ine islands in the Florida Keys A. blodgettii.
Although we do not know the total extent of the former range of Argythamnia blodgettii, approximately 12 miles (19 kilometers) of the species' range has been lost near the northern end of the range in Miami-Dade County and 43 miles (69 kilometers) has been lost in Monroe County on the southern edge of the species' range (Bradley and Gann 1999, p. 3).
Miami-Dade County: According to data from the Institute for Regional Conservation (IRC), the estimated population of Argythamnia blodgettii in Miami-Dade County is 375 to 13,650 plants ( i.e., total of low and high estimates) (K. Bradley 2007, pers. comm.); however, this may be an overestimate of the actual population size because it was based upon a log10 scale. In Everglades National Park (ENP), the current estimated population size is 2,000 plants (J. Sadle 2015, pers. comm.).
Based on the data presented below in Table 4, there are 31 records for Argythamnia blodgettii in Miami-Dade County. Six populations are extant, 11 are extirpated, and the status of 14 is uncertain because they have not been surveyed in 15 years or more.
Monroe County: In the Keys, Argythamnia blodgettii is extant on nine islands, with three others of uncertain status (Hodges and Bradley 2006, p. 43). The largest population surveyed is on Big Munson Island and is estimated to be 8,000 to 9,000 plants (Hodges and Bradley 2006, p. 17). On Big Pine Key, a population of A. blodgettii estimated at 2,200 plants is found scattered across the island. Occurrences are known from the Koehn's subdivision, Long Beach, Cactus Hammock, and Watson Hammock. Sizable populations also occur at Key West Naval Air Station on Boca Chica Key. The total population size in the Florida Keys is estimated to be approximately 13,200 plants (Hodges and Bradley 2006, pp. 10-13, 17).
Argythamnia blodgettii is extirpated from 3 of 16 (23 percent) of the islands that once supported it. Based on the data presented in Table 4, there are 18 records for A
atson Hammock. Sizable populations also occur at Key West Naval Air Station on Boca Chica Key. The total population size in the Florida Keys is estimated to be approximately 13,200 plants (Hodges and Bradley 2006, pp. 10-13, 17).
Argythamnia blodgettii is extirpated from 3 of 16 (23 percent) of the islands that once supported it. Based on the data presented in Table 4, there are 18 records for A. blodgettii in Monroe County. Eleven populations are extant, three are extirpated, and the status of four is uncertain because they have not been surveyed in 15 years or more.
Table 4—Summary of the Status and Trends of the Known Occurrences of Argythamnia blodgettii Population Ownership Most recent population estimate County Trend Extant 17 records Plantation Key, Snake Creek Hammock FWC 101-1,000 (2005) 2 Monroe Insufficient data. Lower Matecumbe Key—Klopp Tract FDEP 6 11-100 (2000) 2 Monroe Insufficient data. Lignumvitae Key FDEP 6 101-1,000 (2005) 2 Monroe Insufficient data. Big Munson Island Private (Boy Scouts of America) 1,001-10,000 (2005) 2 Monroe Insufficient data. North Key Largo DOD, FDOT No estimate (2005) 8 Monroe Insufficient Data. Key Largo—Dove Creek Hammock FWC, FDOT 11-100 (2005) 2 Monroe Insufficient data. Vaca Key (Marathon)—Blue Heron Hammock FWC, FDOT 11-100 (2005) 2 Monroe Insufficient data. Windley Key—State Park FDEP 6 11-100 (2005) 2 Monroe Insufficient data. Boca Chica KWNAS 7 Runway 25 DOD 1,001-10,000 (2004) 2 Monroe Insufficient data. Boca Chica Key KWNAS 7 Weapons Hammock DOD 200 (2004) 2 Monroe Insufficient data. Big Pine Key USFWS, FWC, private ~2,200 (2005) 2 Monroe Insufficient data. ENP Long Pine Key Deer Hammock area (Pine Block A), Turkey Hammock area (Pine Block B), Pine Block E NPS 5 2,000 (2015) 4 Miami-Dade Insufficient data. Camp Choee Private (Girl Scout Council of Tropical Florida) 3 (2005) 3 Miami-Dade Insufficient data. Crandon Park—Key Biscayne Miami Dade Parks and Recreation 4 (2005) 3 Miami-Dade Insufficient data
private ~2,200 (2005) 2 Monroe Insufficient data. ENP Long Pine Key Deer Hammock area (Pine Block A), Turkey Hammock area (Pine Block B), Pine Block E NPS 5 2,000 (2015) 4 Miami-Dade Insufficient data. Camp Choee Private (Girl Scout Council of Tropical Florida) 3 (2005) 3 Miami-Dade Insufficient data. Crandon Park—Key Biscayne Miami Dade Parks and Recreation 4 (2005) 3 Miami-Dade Insufficient data. Martinez Pineland/Larry and Penny Thompson Park Miami Dade Parks and Recreation 6 (2005) 3 Miami-Dade Insufficient data. Tropical Park Pineland Miami Dade Parks and Recreation 20 (2005) 3 Miami-Dade Insufficient data. Boystown Pineland Private No estimate (2005) 3 Miami-Dade Insufficient data. Uncertain 18 records Crawl Key, Forestiera Hammock Private 10 (1982) 3 Monroe Insufficient data. Long Key State Park FDEP No estimate (1999) 2 Monroe Insufficient data. Stock Island Private No estimate (1981) 2 Monroe Insufficient data. Boot Key Private 11-100 (1998) 2 Monroe Insufficient data. Deering Estate State of Florida 11-100 (1991) 1 Miami-Dade Insufficient data. Castellow Hammock Miami Dade Parks and Recreation 11-100 (1991) 1 Miami-Dade Insufficient data. Owaissa Bauer County Park Miami Dade Parks and Recreation 101-1,000 (1991) 1 Miami-Dade Insufficient data. Pine Ridge Sanctuary Private 2-10 (1992) 1 Miami-Dade Insufficient data. County Ridge Estates Private 11-100 (1999) 1 Miami-Dade Insufficient data. Epmore Drive pineland Private 2-10 (1999) 1 Miami-Dade Insufficient data. Gifford Arboretum Pineland Private 2-10 (1999) 1 Miami-Dade Insufficient data. Ned Glenn Nature Preserve Miami Dade Parks and Recreation 11-100 (1999) 1 Miami-Dade Insufficient data. Natural Forest Community #317 Private 2-10 (1999) 1 Miami-Dade Insufficient data. Old Dixie pineland Private 11-100 (1999) 1 Miami-Dade Insufficient data. Owaissa Bauer Addition #1 Miami Dade Parks and Recreation 11-100 (1991) 1 Miami-Dade Insufficient data. SW 184th St. and 83rd Ave. Private 11-100 (1999) 1 Miami-Dade Insufficient data
and Recreation 11-100 (1999) 1 Miami-Dade Insufficient data. Natural Forest Community #317 Private 2-10 (1999) 1 Miami-Dade Insufficient data. Old Dixie pineland Private 11-100 (1999) 1 Miami-Dade Insufficient data. Owaissa Bauer Addition #1 Miami Dade Parks and Recreation 11-100 (1991) 1 Miami-Dade Insufficient data. SW 184th St. and 83rd Ave. Private 11-100 (1999) 1 Miami-Dade Insufficient data. Castellow #33 Private 12 (1995) 3 Miami-Dade Insufficient data. Castellow #31 Private 30-50 (1995) 3 Miami-Dade Insufficient data. Extirpated 14 records Upper Matecumbe Key unknown No estimate (1967) 3 Monroe Totten Key NPS No estimate (1904) 1 Monroe Key West City of Key West No estimate (1965) 1 Monroe Fuch's Hammock Miami-Dade County No estimate (1991) 1 Miami-Dade Brickell Hammock unknown Extirpated 1937 1 Miami-Dade Carribean Park Miami-Dade County Extirpated 1998 1 Miami-Dade Coconut Grove Miami-Dade County Extirpated 1901 1 Miami-Dade Coral Gables area unknown Extirpated 1967 1 Miami-Dade Miller and 72nd Ave unknown Extirpated 1975 1 Miami-Dade Orchid Jungle Miami-Dade County Extirpated 1930 1 Miami-Dade Palms Woodlawn Cemetery Private Extirpated 1992 1 Miami-Dade South of Miami River unknown Extirpated 1913 1 Miami-Dade Bauer Drive Pineland Private No estimate (1985) 3 Miami-Dade Naranja Private No estimate (1974) 3 Miami-Dade 1 Bradley and Gann 1999, p. 6. 2 Hodges and Bradley 2006, pp. 10-17. 3 FNAI 2011. 4 Sadle 2015, pers. comm., p. 1. 5 National Park Service (NPS). 6 Florida Department of Environmental Protection (FDEP). 7 Key West Naval Air Station (KWNAS). 8 Henize and Hipes 2005, p. 25. Biology
Life History and Reproduction: Reproductive biology of Argythamnia blodgettii has not been studied. Reproduction is sexual and flowering and fruiting apparently takes place throughout the year (Bradley and Gann 1999, p. 3).
Fire Ecology and Demography: The fire ecology and demography of Argythamnia blodgettii have not been studied. Populations of A. blodgettii can be ephemeral (Hodges and Bradley 2006, p
ory and Reproduction: Reproductive biology of Argythamnia blodgettii has not been studied. Reproduction is sexual and flowering and fruiting apparently takes place throughout the year (Bradley and Gann 1999, p. 3).
Fire Ecology and Demography: The fire ecology and demography of Argythamnia blodgettii have not been studied. Populations of A. blodgettii can be ephemeral (Hodges and Bradley 2006, p. 14).
Summary of Biological Status and Threats
The Act directs us to determine whether any species is an endangered species or a threatened species because of any one of five factors affecting its continued existence. In this section, we summarize the biological condition of each of the plant species and its resources, and the factors affecting them, to assess the species' overall viability and the risks to that viability.
Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range
Chamaecrista lineata var. keyensis, Chamaesyce deltoidea ssp. serpyllum, Linum arenicola, and Argythamnia blodgettii have experienced substantial destruction, modification, and curtailment of their habitats and ranges (see Background, above). Specific threats to these plants included in this factor include habitat loss, fragmentation, and modification caused by development ( i.e., conversion to both urban and agricultural land uses) and inadequate fire management. Each of these threats and its specific effects on these plants are discussed in detail below.
Human Population Growth, Development, and Agricultural Conversion
The modification and destruction of the habitats that support Chamaecrista lineata var. keyensis, Chamaesyce deltoidea ssp. serpyllum, Linum arenicola, and Argythamnia blodgettii has been extreme in most areas of Miami-Dade and Monroe Counties, thereby reducing these plants' current ranges and abundance in Florida. The
In Miami-Dade County, development and agriculture have reduced pine rocklands habitat by 90 percent in mainland south Florida
that support Chamaecrista lineata var. keyensis, Chamaesyce deltoidea ssp. serpyllum, Linum arenicola, and Argythamnia blodgettii has been extreme in most areas of Miami-Dade and Monroe Counties, thereby reducing these plants' current ranges and abundance in Florida. The
In Miami-Dade County, development and agriculture have reduced pine rocklands habitat by 90 percent in mainland south Florida. Pine rocklands habitat decreased from approximately 74,000 ha (183,000 ac) in the early 1900s, to only 8,140 ha (20,100 ac) in 1996 (Kernan and Bradley 1996, p. 2). The largest remaining intact pine rocklands (approximately 2,313 ha (5,716 ac)) is Long Pine Key in ENP. Outside of ENP, only about 1 percent of the pine rocklands on the Miami Rock Ridge have escaped clearing, and much of what is left are small remnants scattered throughout the Miami metropolitan area, isolated from other natural areas (Herndon 1998, p. 1).
Similarly, most of the pine rocklands in the Florida Keys (Monroe County) have been impacted (Hodges and Bradley 2006, p. 6). Pine rocklands historically covered 1,049 ha (2,592 ac) of Big Pine Key (Folk 1991, p. 188), the largest area of pine rocklands in the Florida Keys. Pine rocklands now cover approximately 582 ha (1,438 ac) of the island, a reduction of 56 percent (Bradley and Saha 2009, p. 3). There were no estimates of pine rocklands area on the other islands historically, but each contained much smaller amounts of the habitat than Big Pine Key. Remaining pine rocklands on Cudjoe Key cover 72 ha (178 ac), Little Pine has 53 ha (131 ac), No Name has 56 ha (138 ac), and Sugarloaf has 38 ha (94 ac). The total area of remaining pine rocklands in the Florida Keys is approximately 801 ha (1,979 ac)
ere no estimates of pine rocklands area on the other islands historically, but each contained much smaller amounts of the habitat than Big Pine Key. Remaining pine rocklands on Cudjoe Key cover 72 ha (178 ac), Little Pine has 53 ha (131 ac), No Name has 56 ha (138 ac), and Sugarloaf has 38 ha (94 ac). The total area of remaining pine rocklands in the Florida Keys is approximately 801 ha (1,979 ac). Currently, about 478 ha (1,181 ac) (82 percent) of the pine rocklands on Big Pine Key, and most of the pine rocklands on these other islands, are protected within the National Key Deer Refuge and properties owned by the Nature Conservancy, the State of Florida, and Monroe County (Bradley and Saha 2009, pp. 3-4). Based on the data presented above, the total remaining acreage of pine rocklands in Miami-Dade and Monroe Counties is now 8,981 ha (22,079 ac) (approximately 8,140 ha (20,100 ac) in Miami-Dade County, and 801 ha (1,979 ac) in the Florida Keys (Monroe County)).
The marl prairies that also support Linum arenicola have similarly been destroyed by the rapid development of Miami-Dade and Monroe Counties. At least some of the occurrences reported from this habitat may be the result of colonization that occurred after they were artificially dried-out due to local or regional drainage.
Likewise, habitat modification and destruction from residential and commercial development have severely impacted rockland hammocks, and coastal berm, that support Argythamnia blodgettii. Rockland hammocks were once abundant in Miami-Dade and Monroe Counties but are now considered imperiled locally and globally (FNAI 2010x, pp. 24-26). The tremendous development and agricultural pressures in south Florida have resulted in significant reductions of rockland hammock, which is also susceptible to fire, frost, hurricane damage, and groundwater reduction (Phillips 1940, p. 167; Snyder et al. 1990, pp. 271-272; FNAI 2010, pp. 24-26)
Dade and Monroe Counties but are now considered imperiled locally and globally (FNAI 2010x, pp. 24-26). The tremendous development and agricultural pressures in south Florida have resulted in significant reductions of rockland hammock, which is also susceptible to fire, frost, hurricane damage, and groundwater reduction (Phillips 1940, p. 167; Snyder et al. 1990, pp. 271-272; FNAI 2010, pp. 24-26).
Pine rocklands, rockland hammock, marl prairie, and coastal habitats on private land remain vulnerable to development, which could lead to the loss of populations of these four species. As noted earlier, all four plants have been impacted by development. The sites of Small's 1907 and 1911 L. arenicola collections in Miami-Dade County are now agricultural fields (Kernan and Bradley 1996, p. 4). A pine rocklands site that supported L. arenicola on Vistalmar Street in Coral Gables (Miami-Dade County) was cleared and developed in 2005, as the Cocoplum housing development. A second pine rocklands site that supported L. arenicola, located on private land on Old Cutler Road, was developed into the Palmetto Bay Village Center. L. arenicola has not been observed at either site since they were developed. A former marl prairie site supporting a sizable population of L. arenicola near Old Cutler Road and Allapatah Drive (SW 112 Ave3.) in Miami-Dade County was extirpated when the site was developed in the 1990s (Bradley and van der Heiden 2013, pp. 6-12, 19). The Boca Chica Key population of L. arenicola was also likely lost due to development (Hodges and Bradley 2006, p. 48).
Bradley and Gann (1999, p. 6) list 12 populations of Argythamnia blodgettii in Miami-Dade County that were lost when the site that supported them was developed. An A. blodgettii population on Key West was likely lost due to the near complete urbanization of the island (Hodges and Bradley 2006, p. 43). Any development related to the Boy Scout camp on Big Munson Island is a potential threat to the largest population A. blodgettii
ist 12 populations of Argythamnia blodgettii in Miami-Dade County that were lost when the site that supported them was developed. An A. blodgettii population on Key West was likely lost due to the near complete urbanization of the island (Hodges and Bradley 2006, p. 43). Any development related to the Boy Scout camp on Big Munson Island is a potential threat to the largest population A. blodgettii.
The largest Linum arenicola population in Miami-Dade County is located on property owned by the Miami-Dade County Homeless Trust. SOCSOUTH, a unified command of all four services of DOD, has entered into a 50-year agreement with Miami-Dade County to lease this 90-ac (36.4-ha) area, where they are building a permanent headquarters on approximately 28 ac (11.3 ha) (DOD 2009, p. 1). As stated above, the population of L. arenicola is spread across the site and was estimated at 74,000 plants in 2009 (Bradley 2009, p. 3). In consultation with the Service, the DOD developed a plan that avoided the majority of the population with accompanying protection and management of approximately 57,725 individuals of sand flax (about 78 percent of the estimated onsite population) (Service 2011, p. 13). The plan will manage 5.95 ha (14.7 ac) of habitat, though most of it is scraped, and only a small portion has a pine canopy (Van der Heiden and Johnson 2013, p. 2). An additional 1.3 ha (3.2 ac) is being managed and supports 13,184 individuals of sand flax (about 18 percent of the estimated onsite population) (Service 2011, p. 13).
Currently there are plans to develop 55 ha (137 ac) of the largest remaining parcel of pine rocklands habitat in Miami-Dade County, the Richmond pine rocklands, with a shopping center and residential construction (RAM 2014, p. 2). Bradley and Gann (1999, p
c) is being managed and supports 13,184 individuals of sand flax (about 18 percent of the estimated onsite population) (Service 2011, p. 13).
Currently there are plans to develop 55 ha (137 ac) of the largest remaining parcel of pine rocklands habitat in Miami-Dade County, the Richmond pine rocklands, with a shopping center and residential construction (RAM 2014, p. 2). Bradley and Gann (1999, p. 4) called the 345-ha (853-ac) Richmond pine rocklands, “the largest and most important area of pine rockland in Miami-Dade County outside of Everglades National Park.” Populations of Argythamnia blodgettii and Linum arenicola, along with numerous federally listed species, occur there. The Miami-Dade County Department of Environmental Resources Management (DERM) has completed a management plan for portions of the Richmond pine rocklands under a grant from the Service and is leading the restoration and management of the Richmond pine rocklands (Bradley and Gann 1999, p. 4). The developer has proposed to enter into a habitat conservation plan in conjunction with their plans to develop their portion of the site and was required by Miami-Dade County Natural Forest Community (NFC) regulations to set aside and manage 15 ha (39 ac) of pine rocklands and 2 ha (4 ac) of rockland hammock. A second project that would result in the loss of pine rocklands habitat is also planned for the
Approximately 25 percent of extant Linum arenicola occurrences (3 of 12 sites), and 44 percent of extant Argythamnia blodgettii occurrences (13 of 34 sites), are located on private land; no extant populations of Chamaecrista lineata var. keyensis or Chamaesyce deltoidea ssp. serpyllum are located entirely on private land. It is possible that the plants on private lands will be lost from most of these sites in the future with increased pressure from development and the other threats described below
nt Argythamnia blodgettii occurrences (13 of 34 sites), are located on private land; no extant populations of Chamaecrista lineata var. keyensis or Chamaesyce deltoidea ssp. serpyllum are located entirely on private land. It is possible that the plants on private lands will be lost from most of these sites in the future with increased pressure from development and the other threats described below. Argythamnia blodgettii is the only one of the four plants species which occurs in ENP, where a population of over 2,000 plants is stable and prescribed fire and other management activities that benefit A. blodgettii are conducted on a regular basis.
Most pine rocklands and rockland hammock habitat is now limited to public conservation lands, where future development and habitat alteration are less likely than on private lands. However, public lands could be sold off (or leased) in the future and become more likely to be developed or altered in a way that negatively impacts the habitat. For example, at the SOCSOUTH site noted above (leased to DOD by Miami-Dade County), ongoing development of headquarters buildings SOCSOUTH has resulted in the loss of L. arenicola and pine rocklands habitat (Bradley and van der Heiden 2013, pp. 8-10). Construction of visitor facilities such as parking lots, roads, trails, and buildings can result in habitat loss on public lands that are set aside as preserves or parks.
Roadside populations of Chamaecrista lineata var. keyensis, Chamaesyce deltoidea ssp. serpyllum, Linum arenicola, and Argythamnia blodgettii are vulnerable to habitat loss and modification stemming from infrastructure projects such as road widening, and installation of underground cable, sewer, and water lines. The Lower Sugarloaf Key population of Linum arenicola was impacted by repaving of the road, which placed asphalt on top of and adjacent to the population (Hodges and Bradley 2006, p. 41).
Although no entire populations of Chamaecrista lineata var. keyensis or Chamaesyce deltoidea ssp
rom infrastructure projects such as road widening, and installation of underground cable, sewer, and water lines. The Lower Sugarloaf Key population of Linum arenicola was impacted by repaving of the road, which placed asphalt on top of and adjacent to the population (Hodges and Bradley 2006, p. 41).
Although no entire populations of Chamaecrista lineata var. keyensis or Chamaesyce deltoidea ssp. serpyllum have been extirpated by habitat loss due to development, the size and extent of these populations have been reduced on Big Pine Key (and surrounding islands for Chamecrista lineata var. keyensis ). The total area of pi

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- [80 FR 1881 Pacific Island Fisheries; Pacific Remote Islands Marine National Monument Expansion](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2015-00444.md)
- [80 FR 2037 Child and Adult Care Food Program: Meal Pattern Revisions Related to the Healthy, Hunger-Free Kids Act of 2010](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2015-00446.md)
- [80 FR 2065 Digital Performance Right in Sound Recordings and Ephemeral Recordings for a New Subscription Service](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2015-00203.md)
- [80 FR 2067 National Emission Standards for Hazardous Air Pollutants: Primary Aluminum Reduction Plants; Extension of Comment Period](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2015-00461.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2015-24291. Check the current official text before relying on it. Not legal advice.