thefederalregister.com

Daily Rules, Proposed Rules, and Notices of the Federal Government

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R4-ES-2012-0076; 4500030113]

RIN 1018-AY08

Endangered and Threatened Wildlife and Plants; Endangered Species Status for Cape Sable Thoroughwort, Florida Semaphore Cactus, and Aboriginal Prickly-Apple, and Designation of Critical Habitat for Cape Sable Thoroughwort

AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
SUMMARY: We, the U.S. Fish and Wildlife Service, propose to listChromolaena frustrata(Cape Sable thoroughwort),Consolea corallicola(Florida semaphore cactus), andHarrisia aboriginum(aboriginal prickly-apple) as an endangered species under the Endangered Species Act, and we propose to designate critical habitat forChromolaena frustrata.We have determined that designation of critical habitat is not prudent forConsolea corallicolaandH. aboriginum.These are proposed regulations, and if finalized, their effect will be to add all three species to the List of Endangered or Threatened Plants and to designate critical habitat for one species under the Endangered Species Act.
DATES: We will accept comments received or postmarked on or before December 10, 2012. Comments submitted electronically using the Federal eRulemaking Portal (seeADDRESSESsection, 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 theFOR FURTHER INFORMATION CONTACTsection by November 26, 2012.
ADDRESSES: (1)Electronically:Go to the Federal eRulemaking Portal:http://www.regulations.gov.In the search box, enter Docket No. FWS-R4-ES-2012-0076, which is the docket number for this rulemaking. Then, click the Search button. You may submit a comment by clicking on "Comment Now!" If your comments will fit in the provided comment box, please use this feature ofhttp://www.regulations.gov,as it is most compatible with our comment review procedures. If you attach your comments as a separate document, our preferred file format is Microsoft Word. If you attach multiple comments (such as form letters), our preferred format is a spreadsheet in Microsoft Excel.

(2)By hard copy:Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS-R4-ES-2012-0076; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, MS 2042-PDM; Arlington, VA 22203.

We request that you send comments only by the methods described above. We will post all comments onhttp://www.regulations.gov.This generally means that we will post any personal information you provide us (see the Information Requested section below for more information).

The coordinates, or plot points, or both, from which the critical habitat maps are generated are included in the administrative record for this rulemaking and are available athttp://www.fws.gov/verobeach/, http://www.regulations.govat Docket No. FWS-R4-ES-2012-0076, and at the South Florida Ecological Services Office (seeFOR FURTHER INFORMATION CONTACT). Any additional tools or supporting information that we have used for this rulemaking will also be available at the Fish and Wildlife Service Web site and Field Office set out above, and may also be included in the preamble of this proposed rule or athttp://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Larry Williams, Field Supervisor, U.S. Fish and Wildlife Service, South Florida Ecological Services 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:

This document consists of: (1) A proposed rule to listChromolaena frustrata Consolea corallicola,andHarrisia aboriginumas an endangered species; and (2) a proposed rule to designate critical habitat forChromolaena frustrata.

Executive Summary

Why we need to publish a rule.Under the Endangered Species Act (Act), a species may warrant protection through listing if it is an endangered or threatened species throughout all or a significant portion of its range.Chromolaena frustrata, Consolea corallicola,andHarrisia aboriginumare highly restricted in their ranges and the threats occur throughout their ranges; therefore, these species qualify for listing. We are proposing to list these plants as endangered species. Their protection under the Act can only be done by issuing a rule.

Chromolaena frustratahas been extirpated (no longer in existence) from half of the islands where it occurred in the Florida Keys, and threats of competition from nonnative plants and habitat loss still exist in the remaining populations.

Consolea corallicolahas been extirpated from half of the islands where it occurred in the Florida Keys, and threats of poaching, predation by a nonnative moth, competition from nonnative plant species, and habitat loss still exist in the remaining populations.

Harrisia aboriginumhas been extirpated from the northern extent of its range in Manatee County, and threats of poaching, competition from nonnative plant species, and habitat loss still exist in the remaining populations.

The basis for our action.Under the Act, a species may be determined to be 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 threats toChromolaena frustratainclude destruction, modification, or curtailment of its habitat or range; inadequate existing regulatory mechanisms; and other natural or man-made factors, including climate change (sea level rise), small populations, and competition from nonnative plant species.

We have determined that threats toConsolea corallicolainclude destruction, modification, or curtailment of its habitat or range; overuse (poaching) and predation; inadequate existing regulatory mechanisms; and other natural or man-made factors, including climate change (sea level rise), small populations, low genetic diversity, and competition from nonnative plant species.

We have determined that the threats toHarrisia aboriginuminclude destruction, modification, or curtailment of its habitat or range; overuse (poaching); inadequate existing regulatory mechanisms; and other natural or man-made factors, including climate change (sea level rise), small populations, and competition from nonnative plant species.

This rule proposes to designate critical habitat forChromolaena frustrata.

• In total, approximately 3,466 hectares (8,565 acres) are being proposed for designation as critical habitat forC. frustrata.The proposed critical habitat is located in Miami-Dade and Monroe Counties, Florida.

• The proposed designation includes both occupied and unoccupied critical habitat, although those areas are not differentiated in the proposed rule or on the maps. Where the unit is not occupied byChromolaena frustrata,we have concluded that the area is essential for the conservation of the species because the designation would allow for the expansion ofChromolaena frustrata`s range and reintroduction of individuals into areas where the species previously occurred.

This rule does not propose critical habitat forConsolea corallicolaorHarrisia aboriginum.We have determined that designation of critical habitat would not be prudent for either species.

• Designation would increase the likelihood and severity of illegal collection ofC. corallicolaandH. aboriginum,and in doing so make enforcement of take prohibitions more difficult.

• These threats outweigh the benefits of designation for the two species.

Peer Review

We are seeking comments from knowledgeable individuals with scientific expertise to review our technical assumptions, analysis of the best available science, and application of that science and to provide any additional scientific information to improve this proposed rule.

Information Requested

We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from other concerned governmental agencies, Native American tribes, the scientific community, industry, or any other interested parties concerning this proposed rule. We particularly seek comments concerning:

(1) The species' biology, range, and population trends, including:

(a) Habitat requirements for feeding, breeding, and sheltering;

(b) Genetics and taxonomy;

(c) Historical and current range, including distribution patterns;

(d) Historical and current population levels, and current and projected trends; and

(e) Past and ongoing conservation measures for the species, its habitat, or both.

(2) The factors that are the basis for making a listing determination for a species under section 4(a) of the Act (16 U.S.C. 1531et seq.), which are:

(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.

(3) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to these species and existing regulations that may be addressing those threats.

(4) Additional information concerning the historical and current status, range, distribution, and population size of these species, including the locations of any additional occurrences or populations of these species.

(5) Any information on the biological or ecological requirements of these species and ongoing conservation measures for these species and their habitats.

(6) The reasons why we should or should not designate habitat as “critical habitat” under section 4 of the Act (16 U.S.C. 1531et seq.), including whether there are threats to all the species from human activity, the degree of which can be expected to increase due to the designation, and whether that increase in threat outweighs the benefit of designation such that the designation of critical habitat is not prudent.

(7) Specific information on:

(a) The amount and distribution ofChromolaena frustratahabitat;

(b) What areas, that were occupied at the time of listing (or are currently occupied) and that contain features essential to the conservation of the species, should be included in the designation and why;

(c) What areas not occupied at the time of listing are essential for the conservation of the species and why.

(8) Land use designations and current or planned activities in the areas occupied byChromolaena frustrataor proposed to be designated as critical habitat, and possible impacts of these activities on the species and proposed critical habitat.

(9) Information on the projected and reasonably likely impacts of climate change onChromolaena frustrata, Consolea corallicola,andHarrisia aboriginum,and proposed critical habitat forChromolaena frustrata.

(10) Probable economic, national security, or other relevant impacts that may result from designating any area that may be included in the final designation. We are particularly interested in any impacts on small entities, and the benefits of including or excluding areas from the proposed designation that are subject to these impacts.

(11) Whether our approach to designating critical habitat could be improved or modified in any way to provide for greater public participation and understanding, or to assist us in accommodating public concerns and comments.

(12) The likelihood of adverse social reactions to the designation of critical habitat and how the consequences of such reactions, if likely to occur, would relate to the conservation and regulatory benefits of the proposed critical habitat designation.

Please include sufficient information with your submission (such as scientific journal articles or other publications) to allow us to verify any scientific or commercial information you include.

Please note that submissions merely stating support for or opposition to the action under consideration without providing supporting information, although noted, will not be considered in making a determination, as section 4(b)(1)(A) of the Act directs that determinations as to whether any species is an endangered or 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 theADDRESSESsection. We request that you send comments only by the methods described in theADDRESSESsection.

If you submit information viahttp://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 onhttp://www.regulations.gov. Please include sufficient information with your comments to allow us to verify any scientific or commercial information you include.

Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection onhttp://www.regulations.gov,or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, South Florida Ecological Services Office, Vero Beach, Florida (seeFOR FURTHER INFORMATION CONTACT).

Previous Federal Actions

Consolea corallicolawas first recognized as a candidate species (under the species' former nameOpuntia spinosissima) on September 27, 1985 (50 FR 39526). It was removed from the candidate list from 1996 to 1998 because there was not sufficient information on the species' biological vulnerability and threats to support issuance of a proposed rule. The 1999 Candidate Notice of Review (CNOR) published in theFederal Registeron October 25, 1999 (64 FR 57534) includedC. corallicola(under the species' previous nameOpuntia corallicola) as a candidate for listing under the Act. We determined that listing was warranted, but was precluded due to workloads and priorities, and we assigned a listing priority number (LPN) of 5 to the species (64 FR 57534). 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. In 2001,C. corallicola(under the species' previous nameOpuntia corallicola) remained a candidate species with the LPN of 5 (66 FR 54808, October 30, 2001). In the 2002 CNOR published on June 13, 2002 (67 FR 40657), and under the nameConsolea (opuntia) corallicola,we changed the LPN of the species from a 5 to a 2 because the threats to the species were found to be more imminent than previously known.Consolea corallicolaretained the LPN of 2 in the 2004 CNOR published on May 4, 2004 (69 FR 24876). We published a finding for the species in the 2005 CNOR on May 11, 2005 (70 FR 24869) in response to a petition received on May 11, 2004. The species remained on the candidate list as published in the CNORs from 2006 to 2011 with the LPN of 2 (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).

Chromolaena frustratawas first recognized as a candidate species in the 1999 CNOR published in theFederal Registeron October 25, 1999 (64 FR 57534). We determined that listing was warranted, but was precluded due to workloads and priorities, and we assigned a LPN of 5 to the species (64 FR 57534). In 2001,C. frustrataremained on the candidate species with the LPN of 5 (66 FR 54808, October 30, 2001). In the 2002 and 2004 CNORs (67 FR 40657, June 13, 2002; 69 FR 24876, May 4, 2004)C. frustrataretained the LPN of 5. We published a finding for the species in the 2005 CNOR on May 11, 2005 (70 FR 24869), in response to a petition received on May 11, 2004. We also changed the LPN of C.frustratafrom a 5 to a 2 because the threats to the species were found to be more imminent than previously known. The species remained on the candidate list as published in the CNORs from 2006 to 2011 with the LNP of 2 (71 FR 53756, September 12, 2006; 72 FR 69034, December 6, 2007; 73 FR 75176, December 10, 2008; 74 FR 578040, November 9, 2009; 75 FR 69222, November 10, 2010; 76 FR 66370, October 26, 2011).

The Service first recognizedHarrisia aboriginumas a candidate species in the CNOR published on September 12, 2006, and we assigned an LPN of 5 (71 FR 53756). We determined that listing was warranted, but was precluded due to workloads and priorities.Harrisia aboriginumretained its candidate status in 2007 (72 FR 69034, December 6, 2007) and an LPN of 5. In the CNOR published on December 10, 2008 (73 FR 75176), we changed the LPN ofH. aboriginumfrom a 5 to a 2 because the threats to the species were found to be more imminent than previously known. The species remained on the candidate list as published in the CNORs from 2009 to 2011 with the LNP of 2 (74 FR 57804, November 9, 2009; 75 FR 69222, November 10, 2010; 76 FR 66370, October 26, 2011).

On May 10, 2011, the Service announced a work plan to restore biological priorities and certainty to the Service's listing process. As part of an agreement with one of the agency's most frequent plaintiffs, the Service filed a work plan with the U.S. District Court for the District of Columbia. The work plan will 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 Candidate Notice of Review, includingChromolaena frustrata, Consolea corallicola,andHarrisia aboriginum,to determine if these species should be added to the Federal Lists of Endangered and Threatened Wildlife and Plants. This work plan will 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 a second frequent plaintiff group and further strengthened the work plan, which will allow the agency to focus its resources on the species most in need of protection under the Act. These agreements were approved on September 9, 2011. The timing of this proposed listing is, in part, therefore, an outcome of the work plan.

Status Assessment forChromolaena frustrata, Consolea corallicola,andHarrisia aboriginum Background

It is our intent to discuss below only those topics directly relevant to the listing ofChromolaena frustrata, Consolea corallicola,andHarrisia aboriginumas endangered in this section of the proposed rule.

Chromolaena frustrata General Biology

Chromolaena frustrata(Family: Asteraceae) is a perennial herb. Mature plants are 15 to 25 centimeters (cm) (5.9 to 9.8 inches ((in)) tall with erect stems. The leaves and stems are covered in short, fuzzy hairs. The leaves have three distinct veins, are roughly oval or egg shaped, and have toothed edges. The blue to lavender flowers are borne in heads usually in clusters of two to six. Flowers are produced mostly in the fall, though sometimes year round (Nesom 2006, pp. 544-545).

Taxonomy, Life History, and Distribution

Chromolaena frustratawas first reported by Chapman in 1886, from the Florida Keys, who called itEupatorium heteroclinium(Chapman 1889, p. 626). Early authors assigned the species to the genusOsmia(Small 1913, p. 147; 1933, p. 1320). In 1970, R.M. King and H.E. Robinson placed this species in the genusChromolaena(King and Robinson 1970, p. 201). Some authors continued to assign the species to the genusEupatorium(i.e., Long and Lakela 1971, p. 873 and Cronquist 1980, p. 185). The authors ofVascular Plants of FloridarecognizeChromolaena frustrata(Wunderlin and Hansen 2008, pp. 1-2). The Integrated Taxonomic Information System (ITIS) (2012, p. 1) indicates that the taxonomic standing forC. frustrata(B.L. Robinson) King and H.E. Robinson is accepted. Synonyms includeEupatorium frustratumB.L. RobinsonandOsmia frustrata(B.L. Robinson) Small.

Climate

The climate of south Florida whereChromolaena frustrataoccurs is classified as tropical savanna and is characterized by distinct wet and dry seasons, a monthly mean temperature above 18 °C (64.4 °F) in every month of the year, and annual rainfall averaging 75 to 150 cm (30 to 60 in) (Gableret al.1994, p. 211). Freezes can occur in the winter months, but are very infrequent at this latitude in Florida.

Habitat

Chromolaena frustratagrows in open canopy habitats, including coastal berms and coastal rock barrens, and in semi-open to closed canopy habitats, including buttonwood forests and rockland hammocks.

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 30 to 305 cm (1 to 10 feet (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 includeBursera simaruba(gumbo limbo),Coccoloba uvifera(seagrape),Coccothrinax argentata(silver palm),Guapira discolor(blolly),Drypetes diversifolia(milkbark),Genipa clusiifolia(seven year apple), andMetopium toxiferum(poisonwood). Characteristic tall shrub and short tree species includeEugenia foetida(Spanish stopper),Ximenia americana(hog plum),Randia aculeata(white indigoberry),Pithecellobium keyense(Florida Keys blackbead),andSideroxylon celastrinum(saffron plum). Short shrubs and herbs includeHymenocallis latifolia(perfumed spiderlily), Capparis flexuosa(bayleaf capertree),Lantana involucrata(buttonsage), andRivina humilis(rougeplant). More seaward berms or those more recently affected by storm deposition may support a suite of plants similar to beaches, including shorelineSesuvium portulacastrum(sea purslane),Distichlis spicata(saltgrass), andSporobolus virginicus(seashore dropseed), or scattered to dense shrub thickets withConocarpus erectus(buttonwood), stuntedAvicennia germinans(black mangrove),Rhizophora mangle(red mangrove),Laguncularia racemosa(white mangrove),Suriana maritima(bay cedar),Manilkara jaimiqui(wild dilly),Jacquinia keyensis(joewood), andBorrichia 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 colonizers to a dense stand of tall shrubs (FNAI 2010a,p. 2).

Coastal Rock Barren

Also known as Keys tidal rock barren or Keys cactus barren, coastal rock barren is confined to the Florida Keys on limestone bedrock along shores facing both Florida Bay and the Straits of Florida. Coastal rock barrens are flat rocklands with much exposed and eroded limestone, little soil or leaf litter, and a sparse cover of stunted halophytic herbs and shrubs in tidal rock barrens (FNAI 2010b, p. 1), or a wide variety of herbs and succulents in cactus barrens (FNAI 2010c, p. 1). The amount of exposed rock varies from practically 0 to over 50 percent of the area.

In tidal rock barrens, patches of low, salt-tolerant herbaceous species includeBorrichia frutescensandB. arborescens(seaside oxeye), Sarcocornia perennis(perennial glasswort),Batis maritima(saltwort),Monanthochloe littoralis(shoregrass), Distichlis spicata, Sporobolus virginicus,andFimbristylis spadicea(marsh fimbry).Conocarpus erectusis the dominant woody plant and varies from stunted, sprawling, multi-stemmed shrubs to tree size. Other typical woody species areRhizophora mangle, Avicennia germinans, Laguncularia racemosa,andLycium carolinianum(christmasberry). At the transition to upland vegetationC. erectusmay be joined by a variety of shrubs and stunted trees of inland woody species, includingSideroxylon celastrinum, Gossypium hirsutum(wild cotton),Pithecellobium keyense, Suriana maritima, Randia aculeata, Manilkara jaimiqui, Metopium toxiferum, Jacquinia keyensis, Maytenus phyllanthoides(Florida mayten), andAcanthocereus tetragonus(barbed-wire cactus) (FNAI 2010b, p. 1).

In cactus barrens, the vegetation consists of a wide variety of herbaceous and succulent species which characteristically includes cacti, agaves, and several rare herbs. Among the latter areEvolvulus convolvuloides(dwarf bindweed),Cienfuegosia yucatanensis(Yucatan flymallow),Jacquemontia pentanthos(skyblue clustervine), andIndigofera mucronatavar.keyensis(Florida Keys indigo). These frequently occur with grasses and sedges, such asLeptochloa dubia(green sprangletop),Paspalidium chapmanii(coral panicum), andCyperus elegans(royal flatsedge). Spiny species, particularly the rareOpuntia triacantha(three-spined pricklypear), are characteristic but their abundance is variable. Other spiny species includeAgave decipiens(false sisal),Acanthocereus tetragonus,andOpuntia stricta(erect pricklypear). Scattered clumps of stunted trees may be present, includingBursera simaruba, Conocarpus erectus, Eugenia foetida,andPithecellobium unguis-cati(catclaw blackbead) (FNAI 2010c, p. 1).

Coastal rock barren occurs above the daily tidal range, but is subject to flooding by seawater during extreme tides and storm events. Salt spray from coastal winds, as well as shallow soils, may limit height growth of woody plants. Aside from bare rock substrate, discontinuous patches of thin marl soils may be present. Fires are rare to non existent in this community (FNAI 2010b, p. 2). The natural process giving rise to cactus barrens is not known, but because they occur on sites where the thin layer of organic soil over limestone bedrock is missing, they may have formed by soil erosion following destruction of the plant cover by fire, storm, or artificial clearing (FNAI 2010c, p. 2).

At its seaward edge, coastal rock barren borders mangrove swamp or salt marshes that are regularly inundated. At its upland edge, coastal rock barrens may grade into rockland hammock or pine rockland (FNAI 2010b, p. 2; 2010c, p. 2).

Buttonwood Forest

Forests dominated by buttonwood often exist in upper tidal areas, especially where mangrove swamp transitions to rockland hammock. These buttonwood forests have canopy dominated byConocarpus erectusand often have an understory dominated byBorrichia frutescens, Lyciumcarolinianum,andLimonium carolinianum(sea lavender) (FNAI 2010d, p. 4).

Temperature, salinity, tidal fluctuation, substrate, and wave energy influence the size and extent of buttonwood forests (FNAI 2010e, p. 3). Buttonwood forests often grade into salt marsh, coastal berm, rockland hammock, and coastal rock barren (FNAI 2010d, p. 5).

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 includeBursera 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,andSwietenia mahagoni(West Indies mahogany). Mature hammocks can 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 ofEugenia(stoppers),Thrinax morrisiiandT. 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-catiandPithecellobium keyense, Coccoloba uvifera,andColubrina arborescens(greenheart). Vines can be common and includeToxicodendron radicans(eastern poison ivy),Smilax auriculata(earleaf greenbrier),Smilax havanensis(Everglades greenbrier),Parthenocissus quinquefolia(Virginia creeper),Hippocratea volubilis(medicine vine), andMorinda royoc(redgal). The typically sparse short shrub layer may includeZamia pumila(coontie) andAcanthocereus tetragonus.Herbaceous species are occasionally present and generally sparse in coverage. Characteristic species includeLasiacis 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. Rockland hammock can be the advanced successional stage of pine rockland, especially in cases where rockland hammock is adjacent to pine rockland. In such cases, when fire is excluded from pine rockland 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 grade into glades marsh, mangrove swamp, salt marsh, coastal rock barren, pine rockland, 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 supportChromolaena frustrata.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 forC. frustrata.

The ecological communities and substrate upon whichChromolaena frustratais found differ between the mainland populations and those in the Florida Keys. The mainland populations occur only in Everglades National Park (ENP), whereC. frustrataoccurs in rockland hammocks and buttonwood forest, often occupying the transitional areas (ecotone) between these habitats and salt marsh dominated byConocarpus erectusand salt-tolerant species, on marl (an unconsolidated sedimentary rock or soil consisting of clay and lime) substrate (Sadle 2008 and 2012, pers. comm.). In the Florida Keys,C. frustrataoccurs on coastal rock barrens, coastal berms, and rockland hammocks on exposed bare limestone rock or with a thin layer of leaf litter (Bradley and Gann 1999, p. 37).Chromolaena frustratais often found in the shade of associated canopy and subcanopy plant species; these canopies bufferC. frustratafrom full exposure to the sun (Bradley and Gann 1999, p. 37).

Historical Range

Chromolaena frustratawas historically known from Monroe County, both on the Florida mainland and the Keys, and in Miami-Dade County along Florida Bay (Bradley and Gann 1999, p. 36). In mainland Monroe County,C. frustratawas known from the Flamingo area to the Madeira Bay area in what is now ENP. In the Florida Keys,C. frustratawas known from Key Largo to Boca Grande Key (Bradley and Gann 1999, p. 36; Bradley and Gann 2004, p. 2). The species was observed historically on Big Pine Key, Boca Grande Key, Fiesta Key, Key Largo, Key West, Knight's Key, Lignumvitae Key, Long Key, Upper Matecumbe Key, and Lower Matecumbe Key (Bradley and Gann 1999, p. 36; Bradley and Gann 2004, pp. 4-7).

The common name ofChromolaena frustrata,Cape Sable thoroughwort, places it in a locality where it may have never occurred. Usage of this place name may have been referring to the greater Cape Sable-Flamingo area, and not specifically to Cape Sable itself. No additional specimens or verifiable reports have documented it on Cable Sable proper. Other reports ofC. frustrataare also suspect. It was reported from “Turner's River Hammock” in Collier County and the Ten Thousand Islands area of ENP, but no voucher specimen has ever been located for these collections (Bradley and Gann 2004, p. 7).

Current Range

In ENP, the species appears to have a distribution approaching what was reported historically. Eleven populations supporting approximately 1,500 to 2,500 plants occur in buttonwood forests and rockland hammocks from the Coastal Prairie Trail near the southern tip of Cape Sable to Madeira Bay (Sadle 2007 and 2012, pers. comm.).

In the Florida Keys,Chromolaena frustratahas been extirpated from half of the islands where it occurred (Bradley and Gann 2004, p. 4). It no longer occurs on Key Largo, Big Pine Key, Fiesta Key, Knight's Key, or Key West (Bradley and Gann 2004, pp. 4-6). The current range ofC. frustrataincludes a small portion of ENP, and six islands in the Florida Keys (Upper Matecumbe Key, Lower Matecumbe Key, Lignumvitae Key, Long Key, Big Munson Island, and Boca Grande Key) (Bradley and Gann 2004, pp. 3-4). Extant populations ofC. frustrataare identified in Table 1 and discussed below.

Table 1—Extant populations ofChromolaena frustrata. Population Ownership Size
  • Numbers of plants
  • Habitat
    Everglades National Park—Flamingo District Federal—National Park Service 1634-2633 (Sadle 2012, pers. comm.) Buttonwood forest, rockland hammock. Upper Matecumbe—Choate Tract State—Florida Department of Environmental Protection 18 (Bradley and Gann 2004, pp. 3-6) Coastal rock barren, rockland hammock. Lower Matecumbe—Klopp Tract State—Florida Department of Environmental Protection 15 (Duquesnel 2012, pers. comm.) Coastal rock barren, rockland hammock. Lignumvitae Key State—Florida Department of Environmental Protection 81 (Bradley and Gann 2004, pp. 3-6) Rockland hammock. Long Key State Park State-Florida Department of Environmental Protection 200 (Bradley and Gann 2004, pp. 3-6) Coastal rockland barren. Long Key—North Layton Hammock State—Florida Department of Environmental Protection—and Private 162 (Bradley and Gann 2004, pp. 3-6) Coastal rock barren, rockland hammock. Big Munson Island Private 4,500 (Bradley and Gann 2004, pp. 3-6) Rockland hammock. Key West National Wildlife Refuge—Boca Grande Key Federal—Fish and Wildlife Service 25 (Bradley and Gann 2004, pp. 3-6) Rockland hammock.
    Demographics

    Little is known about the long-term demographics or population trends ofChromolaena frustrata.Populations may experience declines due to the effects of hurricanes and storm surges, but the species appears to be able to rebound at affected sites within a few years. For example, after Hurricane Wilma in 2005, some populations ofC. frustratavanished and the habitat at these sites was significantly altered due to hurricane storm surge (Duquesnel 2005, pers. comm.; Bradley 2007, pers. comm.; Maschinski 2007, pers. comm.). However, it appears that the species is returning at these locations (Bradley 2009, pers. comm.). Furthermore, canopy disturbance may also benefit the species, as it has been speculated that the large number of plants observed at Big Munson Island in 2003 was due to thinning of the hammock canopy caused by Hurricane Georges in 1998 (Bradley and Gann 2004, p. 4).

    Reproductive Biology and Genetics

    The reproductive biology and genetics ofChromolaena frustratahave not been studied (Bradley and Gann 1999, p. 37). We have no other information available regarding the ecology of the species beyond the habitat preferences and demographic trends discussed above.

    Consolea corallicola

    Consolea corallicola(Family: Cactaceae) is a tree-like cactus; mature plants grow 2 meters (m) (6 feet (ft)) tall with an erect main trunk, which is elliptical or oval in cross section and armed with spines. Near the top of the plant there is a dense cluster of branches. The stem branches (pads) are green, elliptical, relatively thin, often curved, and 12 to 30 cm (5 to 12 in) long. The spines are in clusters of five to nine, 7 to 11 cm (2.8 to 4.7 in) long, needle-like, with one of the spines much longer than the others. Spines on the main stems of older plants are enlarged. The flowers are bright red and 1.3 to 1.9 cm (0.50 to 0.75 in) wide, and the fruits are yellow, egg-shaped, and 2.5 to 5.1 cm (1 to 2 in) long (Small 1930, pp. 25-26; Anderson 2001, pp. 170-171).

    Taxonomy

    John Kunkel Small discovered and describedConsolea corallicolain 1930 (Small 1930, pp. 25-26). In 1971, Long and Lakela (1971, p. 626) reassigned the plants occurring in the Florida Keys toOpuntia spinosissimaMiller, a species restricted to the Blue Hills of south coastal Jamaica. Austinet al.(1998, pp. 151-158) determined that the plants in Florida are morphologically distinct fromO. spinosissimaand retained them asO. corallicola.Genetic studies by Gordon and Kubisiak (1998, p. 209) confirmed that the Florida plants are a genetically distinct species. Recent taxonomic treatments accept the genusConsoleaand apply the nameC. corallicolato the Florida species (Areces-Mallea 1996, pp. 224-226; Anderson 2001, pp. 170-171; Parfitt and Gibson 2004a, pp. 92-94). Synonyms includeOpuntia corallicola(Small) Werdermann (Parfitt and Gibson 2004, p. 94).

    Climate

    The climate of south Florida whereConsolea corallicolaoccurs is classified as tropical savanna, as described above forChromolaena frustrata.

    Habitat

    Consolea corallicolaoccurs in rockland hammocks near sea level (Small 1930, pp. 25-26; Benson 1982, p. 531) and in buttonwood forests in the transitional area between rockland hammocks and mangrove swamps (Bradley and Gann 1999, p. 77; Gannet al.2002, p. 480; Higgins 2007, pers. comm.). These community types are described above forChromolaena frustrata. Consolea corallicolaoccurs on sandy soils and limestone rockland soils with little organic matter (Small 1930, pp. 25-26) and seems to prefer areas where canopy cover and sun exposure are moderate (Grahl and Bradley 2005, p. 4).

    Historical Range

    Consolea corallicolawas known historically from three islands of the Florida Keys in Monroe County (Small 1930, pp. 25-26) and one small island in Biscayne Bay in Miami-Dade County (Bradley and Woodmansee 2002, p. 810). A population on the southeast portion of Big Pine Key in the Florida Keys (Small 1921, p. 50) was extirpated by the 1960s, as a result of road building and “collecting by cactus enthusiasts” (Bradley and Gann 1999, p. 77). A population known from Key Largo in the Florida Keys was also extirpated, although the cause of its loss is unknown (Bradley and Woodmansee 2002, p. 810).

    Current Range

    The current range ofConsolea corallicolaincludes two naturally occurring populations, one in Biscayne National Park (BNP; Miami-Dade County) and one on a small island in the Florida Keys (Monroe County) (Bradley and Gann 1999, p. 77; Bradley and Woodmansee 2002, p. 810). These naturally occurring populations account for fewer than 1,000 plants.Consolea corallicolawas also reintroduced at several sites in the Florida Keys, and plants survive at two of these sites on State-owned lands (Stiling 2009, pers. comm.; Stiling 2010, p. 1; Duquesnel 2011a,b, pers. comm.). Both sites together represent fewer than 50 plants. A survey of other areas containing suitable habitat in BNP was undertaken in 2002 and 2003, to locate additional populations, but none were found (Bradley and Koop 2003, p. 2).

    Extant populations ofConsolea corallicolaare provided in Table 2 and are discussed below.

    Table 2—Extant Populations of Consolea corallicola Population Ownership Size Habitat Trend Biscayne National Park Federal—National Park Service 600 (McDonough 2010a, pers. comm.) rockland hammock Stable. Island in Florida Keys Private—The Nature Conservancy 9 to 11 adults, 100s of juveniles (Gun 2012, pers. comm.) rockland hammock, rockland hammock-buttonwood forest ecotone Declining. Island in Florida Keys (reintroduced) State—Florida Department of Environmental Protection 40 juveniles (Duquesnel 2011a, pers. comm.) buttonwood forest-saltmarsh ecotone, coastal rock barren Declining. Island in Florida Keys (reintroduced) State—Florida Fish and Wildlife Conservation Commission 7 juveniles (Stiling 2010, p.1) Unknown Declining. Reintroductions

    Experimental plantings ofConsolea corallicolawere conducted at several sites on State and Federal conservation lands in the Florida Keys from 1996 to 2004. However, these plantings were largely unsuccessful (with most plants succumbing toCactoblastismoth damage or rot), and plants currently remain at only two of these sites, one of which is inundated too frequently during high tides to be favorable for population expansion (Duquesnel 2008, 2009, 2011a,b, pers. comm.; Stiling 2007, p. 2; Stiling 2009, pers. comm.; Stiling 2010, pp. 2, 193-194).

    Reproductive Biology and Genetics

    Consolea corallicolaflowering occurs throughout the year, but peaks in February and March (Bradley and Koop 2003, p. 2). Plants ofC. corallicolaare functionally dioecious (i.e., with male and female flowers on separate plants), but the flowers give the appearance of a species that is hermaphroditic with perfect flowers (i.e., each flower produces stamens and ovules) (Negrón-Ortiz and Strittmatter 2004, p. 22; Negrón-Ortiz 2007a, p. 3; 2007b, p. 1362).

    Sexual reproduction has not been observed inConsolea corallicola.All documentedC. corallicolareproduction has been vegetative (clonal), with new plants originating from pads that fall from larger plants and take root (Negrón-Ortiz 1998, p. 208). Survival rates of fallen pads in research populations are low due to rot andCactoblastismoth damage (Stiling 2010, p. 193; see Summary of Factors Affecting the Species below). Production of seeds is rare and the few seeds that have been observed are thought to be the product of asexual seed reproduction (agamospermy) (Negrón-Ortiz 1998, p. 211). Two hypotheses have been suggested to explain the lack of seed production ofC. corallicola.The first hypothesis is that the species is a sterile polyploid (abnormal cell division that results in more than two sets of chromosomes) (Negrón-Ortíz 1998, p. 212). An alternative hypothesis is the dioecious breeding system ofC. corallicola.All plants in the known populations produce only male flowers, and no female individuals have ever been located. As a result, all existing occurrences ofC. corallicolaappear to be incapable of sexual reproduction at this time (Negrón-Ortiz and Strittmatter 2004, p. 22).

    Cariagaet al.(2005, pp. 225-230) found no genetic diversity within the two remaining wild populations ofConsolea corallicolaand concluded that all plants within each population are likely derived clonally from a single parent plant. These data support asexual propagation as the reproductive strategy ofC. corallicola.However, there is a small amount of variation between the two remaining wild populations, suggesting the possibility that they originated from different parent plants (Lewis 2007, p. 3). Likewise, Cariagaet al.(2005, p. 225) found that a single plant collected by George Avery in 1963 from Big Pine Key and maintained at Fairchild Tropical Botanical Gardens was a unique genotype, but Lewis (2007, pp. 6-7) found it to be identical to the plants from the other populations. Thus,C. corallicolahas extremely limited genetic diversity, consisting of just one to three genetic lines.

    Demographics

    Annual monitoring has provided a perspective on the population structure and dynamics ofConsolea corallicola.The wild population at BNP was monitored from 2002 to 2005. At the beginning of the study, the population consisted of 655 plants. At the end of the 3-year study in 2005, 594 plants were alive, and 61 had died (9 percent decline). Only 8 percent of plants produced flowers, and plants grew very slowly (about 1.2 cm (0.5 in) per year) (Grahl and Bradley 2005, pp. 4-5). From 2008 to 2010, the population was estimated to number approximately 600 individuals (McDonough 2010a, pers. comm.). Annual fluctuations in the number of plants is largely due to mortality of branches (pads) that fall from the larger plants but fail topermanently establish (McDonough 2010a, pers. comm.). Overall, the number of plants comprising this population appears to be stable (Bradley and Koop 2003, p. 2; Grahl and Bradley 2005, p. 2; McDonough 2010a, pers. comm.).

    Population decline has been shown in a wild population on an island in the Florida Keys, which now consists of 9 to 11 adult plants (defined as plants greater than 91.4 cm (3 ft) tall) and hundreds of small juveniles originating from fallen pads. Overall, the number of adult plants in this population has declined more than 50 percent over the past 10 years, due to crown rot and damage caused by theCactoblastismoth and hurricanes (Higgins 2007, pers. comm.; Gun 2012, pers. comm.; see Summary of Factors Affecting the Species below).

    Harrisia aboriginum Description

    Harrisia aboriginum(Family: Cactaceae) is a sprawling cactus, usually with multiple stems arising from a single base. The stems are erect, slender, and cylindrical. They possess 9 to 11 longitudinal ribs, and may reach 6 m (20 ft) in height. Spines are 1.0 cm (0.4 in) long and originate in clusters of seven to nine spines. Flowers are funnel-shaped, white, up to 15 cm (5.9 in) long, and have a slight scent. The inside of the flower is lined with stiff, brown hairs. Fruits are yellow, round in shape, and 6.1 to 7.6 cm (2.4 to 3.0 in) in diameter (Small in Britton and Rose 1920, p. 154; Anderson 2001, p. 370; Parfitt and Gibson 2004b, p. 153). Each fruit contains hundreds of small black seeds. Plants in full to partial sun typically consist of several stems from a single base. Plants shaded by overstory vegetation usually have stems that tend to be slender and taller. These slender stems will topple over and eventually recorrect their growth upward, or they may reproduce new upright stems along the prostrate stems. Some of the prostrate stems deteriorate over time, obscuring the clonal origin (single source) of upright stems. This results in more diffuse groupings of clonal stems leaning at various angles (Bender 2011, p. 18).

    Taxonomy

    Harrisia aboriginumwas described by John Kunkel Small, after he discovered it in Manatee County in 1919 (Small in Britton and Rose 1920, p. 154). This name is still in use (Parfitt and Gibson 2004b, p. 153; Wunderlin and Hansen 2008, pp. 1-2), although possible alternative names for the species have been proposed over the years. The genus-level placement ofH. aboriginumand other Florida relatives has been in flux since they were first described, with some authors placing them in the large and variable genusCereus(i.e. Benson 1969, p. 126), and others segregating them into the smallerHarrisiagenus. Recent authors have included the Florida species in the genusHarrisia(Hooten 1991, pp. 64-66; Anderson 2001, p. 370; Ward 2004, pp. 365-371; Parfitt and Gibson 2004b, pp. 150-153; Wunderlin and Hansen 2008, pp. 1-2).

    Based upon the best available scientific information,Harrisia aboriginumis a distinct taxon, endemic to the west coast of Florida. Synonyms includeCereus aboriginum(Small ex Britton and Rose) Little,C. gracilisvar.aboriginus(Small ex Britton and Rose) L. D. Benson, andHarrisia donae-antoniaeHooten (Parfitt and Gibson 2004b, p. 153).

    Climate

    The climate of south Florida whereHarrisia aboriginumoccurs is classified as tropical savanna as described above forChromolaena frustrata.

    Habitat

    Harrisia aboriginumoccurs on coastal berms, coastal strand, coastal grasslands and maritime hammocks, with a sand substrate. It also occurs on shell mounds with a calcareous shell substrate (Bradleyet al.2004, pp. 4, 14). The coastal berm community is described above forChromolaena frustrata. Harrisia aboriginumgrowing in coastal berm habitat sometimes occur close to the mangrove zone, but never within it.

    Coastal Strand

    Coastal strand is an evergreen shrub community growing on stabilized coastal dunes. It is usually the first woody plant community inland from the coast. On the southwest Gulf coast of Florida, coastal strand is patchily distributed. It usually develops as a band between dunes dominated byUniola paniculata(sea oats) along the immediate coast, and maritime hammock, scrub, or mangrove swamp communities farther inland. On broad barrier islands, it may also occur as patches of shrubs within a coastal grassland matrix (FNAI 2010f, p. 2).

    On the southwest Gulf coast of Florida, the species composition of coastal strand consists of tropical plant species, includingCoccoloba uvifera, Forestiera segregata(Florida swampprivet),Rapanea punctata(myrsine),Lantana involucrata, Randia aculeata, Chiococca alba(snowberry),Eugenia foetida, Guapira discolor, Zanthoxylum fagara(wild lime),Pithecellobium keyense, Chrysobalanus icaco(coco plum),Dalbergia ecastaphyllum(coinvine),Sophora tomentosavar.truncata(yellow necklacepod),Caesalpinia bonduc(gray nicker),Sideroxylon celastrinum,andJacquinia keyensis,(FNAI 2010f, p. 2).

    Soils are deep, well-drained sands and may be somewhat alkaline, consisting of quartz sand mixed with varying proportions of shell fragments (FNAI 2010f, p. 2).

    Storm waves periodically destroy dunes and the coastal strand behind them, with the resulting bare area being recolonized first by pioneer beach species and then by coastal grassland. The resulting coastal grassland is in turn invaded by patches of woody species, which eventually coalesce into a continuous woody community of coastal strand. Natural disturbances, such as strong winds and storm surge associated with hurricanes, or hard freezes, serve to open up coastal strand canopies. There is little information on natural fire frequency in coastal strand (FNAI 2010f, p. 2).

    Coastal strand is distinguished from maritime hammock by the absence of distinct tree canopy and understory layers. It is distinguished from coastal berm and shell mound by its occurrence on sand deposits along a high-energy sandy coast, rather than on shell deposits along a low-energy, mangrove-dominated coast. It is distinguished from coastal grassland by the dominance of woody, rather than herbaceous, species.

    Coastal Grassland

    Coastal grassland is a predominantly herbaceous community occupying the drier portions of the transition zone between beach dunes on the immediate coast and communities dominated by woody species, such as coastal strand or maritime hammock, farther inland. It occurs primarily on the broader barrier islands and capes along the sandy coasts of Florida. The specialized dune building grasses of the beach dune community,Uniola paniculata, Panicum amarum(bitter panicgrass), andSpartina patens(saltmeadow cordgrass), are usually present, along with a variety of other herbaceous species typically found on more stable soils, such asAndropogonandSchizachyrium(bluestem grasses),Heterotheca subaxillaris(camphorweed), andSmilax auriculata.On the southwest Gulf coast, a distinctive coastal grassland community is found on the broad barrier islands such as Cayo Costa, North Captiva, andformerly Captiva and Sanibel. It consists of a short, dense sward (a portion of ground covered with grass) ofBouteloua hirsuta(hairy grama). Other species present includeErnodea littoralis(beach creeper),Opuntia stricta,andLantana depressavar.sanibelensis(Gulf Coast Florida lantana) (FNAI 2010g, entire).

    Coastal grassland develops either as a barrier island builds seaward, developing new dune ridges along the shore that protect the inland ridges from sand burial and salt spray, or as a beach recovers after storm overwash and a new foredune ridge builds up along the shore, protecting the overwashed area behind it from sand burial and salt spray. As time passes, absent further storms, the coastal grassland community itself will gradually be replaced by woody species to form scrub, coastal strand, or maritime hammock communities (FNAI 2010g, entire).

    Fire is naturally rare and localized in this community, with water barriers and sparse fuels combining to limit its spread (FNAI 2010g, entire).

    Coastal grassland is distinguished from the beach dune community by its position inland from the immediate coastline and the presence of a variety of grasses, forbs, and pioneer dune-building grasses. It differs from coastal berm in its position on a sandy coast, rather than on a storm-deposited shell ridge on a mangrove-dominated shoreline. Coastal grassland is distinguished from coastal strand and maritime hammock in being dominated by herbaceous, rather than woody, species (FNAI 2010g, entire).

    Maritime Hammock

    Maritime hammock is a predominantly evergreen hardwood forest growing on stabilized coastal dunes lying at varying distances from the shore. On the southwest Gulf coast of Florida, most of the barrier islands and peninsulas are long and narrow with correspondingly small, narrow areas of hammock. Maritime hammock is best developed on the few broad islands, including Caladesi, Cayo Costa, North Captiva, and the inner barrier islands at Stump Pass and Keewaydin Island (FNAI 2010h, entire).

    Canopy species includeCococarpus erectus, Piscidia piscipula, Bursera simaruba, Sideroxylon foetidissimum, Exothea paniculata, Eugenia axillaris(white stopper),Ficus aurea, Coccoloba uvifera, Eugenia foetida,andPithecellobium keyense;shrubs includeRapanea punctata, Myrcianthes fragrans(Simpson's stopper),Ardisia escallonioides, Psychotria nervosa, Chiococca alba,andRandia aculeata.Cacti and other spiny species, such asAgave sisalana(sisal)and Acanthocereus tetragonus,may also be present. The herb layer is sparse to absent (FNAI 2010h, entire).

    Maritime hammock occurs on deep, well-drained, acid quartz sands, or well-drained, moderately alkaline, quartz sands mixed with shell fragments (FNAI 2010h, entire).

    Due to their coastal location with water barriers on at least one, if not two sides, fire was probably naturally rare and very spotty in maritime hammock, especially on the narrower barrier islands. Maritime hammocks are principally influenced by wind-borne salt spray, storm waves, and sand burial. If storm waves destroy the protective dunes seaward of the hammock, sand can blow inland, burying the trees. In addition to physical destruction by storm waves, hammock trees are susceptible to being killed by standing salt water deposited in low areas by storm surge (FNAI 2010h, entire).

    Tropical maritime hammock can be distinguished from rockland hammock by their occurrence on sand substrate, rather than limestone. They may be similar in species composition to coastal berm, being distinguished primarily by location along a high wave energy sandy coast, rather than a low-energy, mangrove-dominated coast, and the presence of a distinct canopy layer. They are very similar to shell mounds in species composition, being distinguished by their occurrence on a natural sand deposit rather than on pure shell (FNAI 2010h, entire).

    Shell Mound

    Shell mounds are small hills, usually in coastal locations, composed entirely of shells (clams, oysters, whelks) discarded by generations of Native Americans. Shell mounds are found along the coast throughout Florida and range westward and northward along the coastlines of the southeastern United States. Originally, there were many such shell mounds along coastal lagoons and at the mouths of rivers, but most were destroyed for road building in the early part of the last century. A rich, calcareous soil develops on the deposited shells, which supports a diverse hardwood forest on undisturbed mounds. Several shell mounds are now surrounded by mangroves, evidence that they were built when sea level was lower than today (FNAI 2010i, entire).

    The plant species composition of shell mound forests tends to be more strictly tropical than that of maritime hammocks on sandy substrates in the same region. South Florida shell mounds are often characterized by tropical tree species such asBursera simaruba, Eugenia axillaris, Amyris elemifera, Zanthoxylum fagara, Sideroxylon foetidissimum, Exothea paniculata, Ficus aurea,andOcotea coriacea.Characteristic shrub species includeChiococca alba, Forestiera segre