Endangered and Threatened Wildlife and Plants; Determination of Status for Texas Golden Gladecress and Neches River Rose-mallow and Designation of Critical Habitat
Federal RegisterSep 11, 2012
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2012-0064; 4500030113]
RIN 1018-AX74
Endangered and Threatened Wildlife and Plants; Determination of Status for Texas Golden Gladecress and Neches River Rose-mallow and Designation of Critical Habitat
AGENCY:
Fish and Wildlife Service, Interior.
ACTION:
Proposed rule.
SUMMARY:
We, the U.S. Fish and Wildlife Service, propose to list two Texas plants,
Leavenworthia texana
(Texas golden gladecress) as an endangered species and
Hibiscus dasycalyx
(Neches River rose-mallow) as a threatened species under the Endangered Species Act of 1973, as amended (Act) and propose to designate critical habitat for both species. These are proposed regulations, and if finalized the effect of these regulations will be to conserve the species and protect their habitat under the Endangered Species Act.
DATES:
We will accept comments received or postmarked on or before November 13, 2012. We must receive requests for public hearings, in writing, at the address shown in the
ADDRESSES
section by October 26, 2012.
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 Keyword box, enter Docket No. FWS-R2-ES-2012-0064, 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 “Send a Comment or Submission.”
(2)
By hard copy:
Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS-R2-ES-2012-0064; 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 on
http://www.regulations.gov.
This generally means that we will post any personal information you provide us (see the Public Comments section below for more information).
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 at
http://www.fws.gov/southwest/es/ElectronicLibrary/ElectronicLibrary_Main.cfm, http://www.regulations.gov
at Docket No. FWS-R2-ES-2012-0064, and at the Corpus Christi Ecological Services Field Office (see
FOR FURTHER INFORMATION CONTACT
). Any additional tools or supporting information that we may develop 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 and/or at
www.regulations.gov
.
FOR FURTHER INFORMATION CONTACT:
Allan Strand, Field Supervisor, U.S. Fish and Wildlife Service, Corpus Christi Ecological Services Field Office, 6300 Ocean Drive, Unit 5837, Corpus Christi, Texas, 78412-5837, by telephone 361-994-9005 or by facsimile 361-994-8262. 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 Endangered Species Act (Act), a species may warrant protection through listing if it is determined to be an endangered or threatened species throughout all or a significant portion of its range.
Leavenworthia texana
(Texas golden gladecress) and
Hibiscus dasycalyx
(Neches River rose-mallow) have been candidates for listing since 1997, but action has been precluded by higher priority listings. As part of a court-approved settlement, we agreed to reevaluate the status of both species and after conducting a thorough review of the current status and level of threats to both species and their habitats between fall 2011 and winter 2012, we concluded that listing, and designation of critical habitat, for both species is warranted.
This rule proposes to add both species to the Federal Lists of Threatened and Endangered Animals and Plants and proposes to designate critical habitat for both species.
• We propose to list the Texas golden gladecress and the Neches River rose-mallow as an endangered and threatened species, respectively, under the Act.
We propose to designate approximately 1,353 acres (ac) (539 hectares (ha)) of critical habitat for the gladecress in Sabine and San Augustine Counties, and approximately 187.8 ac (76.0 ha) of critical habitat for the rose-mallow in Cherokee, Houston, Trinity, Harrison, and Nacogdoches Counties, Texas.
The basis for our action.
Under the Act, we can 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 both species are negatively affected by the following:
• Habitat loss and degradation of herbaceous glade plant communities supporting the gladecress, and of open habitats on hydric alluvial soils along sloughs, oxbows, terraces, and wetlands of the Neches River or Mud and Tantabogue Creeks that support the rose-mallow. Activities or factors negatively impacting the habitat of the gladecress include: Glauconite quarrying; natural gas and oil exploration and production; invasion of open glades by nonnative and native shrubs, trees, and vines, and other weedy species; pine tree plantings in close proximity to occupied glades; and herbicide applications that have potential to kill emerging seedlings. The rose-mallow's habitat is being lost and degraded by encroachment of nonnative and native plant species, particularly trees, herbicide use, livestock trampling, and alteration of natural hydrology of seasonal flooding to conditions where habitat has been drained or has become permanently flooded. Prolonged or frequent droughts can exacerbate habitat degradation for both species.
• Lack of existing regulatory mechanisms to protect either species or their habitats.
• Other natural or manmade factors, including low numbers of individual plants and few remaining populations. The species' natural variability that is associated with climatic conditions can be negatively affected by the effects of drought.
Also under the Act, upon making a determination that a species warrants listing as an endangered or threatened species, we are required to designate critical habitat to the maximum extent prudent and determinable. We are required to base the designation on the best available scientific data after taking into consideration economic and other impacts. We can exclude an area from critical habitat if the benefits of
exclusion outweigh the benefits of designation, unless the exclusion will result in the extinction of the species.
This rule proposes to designate critical habitat for each species.
We are proposing to designate critical habitat for both species in East Texas as follows:
• Approximately 1,353 acres (ac) (539 hectares (ha)) are designated as critical habitat for Texas golden gladecress.
• Approximately 178 ac (76 ha) are designated as critical habitat for Neches River rose-mallow.
We are planning to prepare an economic analysis.
To ensure that we consider the economic impacts, we will prepare an economic analysis of the proposed critical habitat designations. We will use the data from the economic analysis to inform the final rule.
We will seek peer review.
We are seeking comments from independent specialists to ensure that our assessment of threats and their impacts on these species, as well as our critical habitat designations, are based on the best available scientifically sound data, assumptions, and analyses. We have invited these peer reviewers to comment on our proposed listing of the gladecress and the rose-mallow and our critical habitat designations. Because we will consider all comments and information received during the comment period, our final determinations may differ from this proposal.
This document consists of: (1) One proposed rule to list the
Leavenworthia texana
as an endangered species; (2) one proposed rule to list the
Hibiscus dasycalyx
as a threatened species; and (3) proposed critical habitat designations for each species. For the purposes of this document, we will refer to
Leavenworthia texana
as Texas golden gladecress or gladecress and
Hibiscus dasycalyx
as Neches River rose-mallow or rose-mallow.
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 the public, 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) These species' biology, range, and population trends, including:
(a) Habitat requirements for pollination, reproduction, and dispersal;
(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 these species, their 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. 1531
et seq.
), which are:
(a) The present or threatened destruction, modification, or curtailment of their 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 their 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 populations of these species;
(5) Any information on the biological or ecological requirements of the species, and ongoing conservation measures for the species and their habitat;
(6) The reasons why we should or should not designate habitat as “critical habitat” under section 4 of the Act (16 U.S.C. 1531
et seq.
), including whether there are threats to these species from human activity, the degree of which can be expected to increase due to the designation, and whether that increase in threats outweighs the benefit of designation such that the designation of critical habitat is not prudent.
(7) Specific information on:
(a) The amount and distribution of the Texas golden gladecress and Neches River rose-mallow and their habitat;
(b) What may constitute “physical or biological features essential to the conservation of these species,” within the geographical range currently occupied by these species;
(c) Where these features are currently found;
(d) Whether any of these features may require special management considerations or protection;
(e) What areas, that were occupied at the time of listing (or are currently occupied) and that contain features essential to the conservation of these species, should be included in the designation and why;
(f) What areas not occupied at the time of listing are essential for the conservation of these species and why;
(8) Land use designations and current or planned activities in the areas occupied by these species or proposed to be designated as critical habitat, and possible impacts of these activities on these species and proposed critical habitat;
(9) Information on the projected and reasonably likely impacts of climate change on these species and proposed critical habitat;
(10) Any foreseeable 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 designations.
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 a threatened or endangered 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.
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 on
http://www.regulations.gov,
or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Corpus Christi Ecological Services Field Office (see
FOR FURTHER INFORMATION CONTACT
, above).
Previous Federal Actions
We first identified the Texas golden gladecress and Neches River rose-mallow as candidates for listing in the September 19, 1997, Notice of Review of Plant and Animal Taxa that are Candidates or Proposed for Listing as Endangered or Threatened Species (62 FR 49397). Candidates are those fish, wildlife, and plants for which we have on file sufficient information on biological vulnerability and threats to support preparation of a listing proposal, but for which development of a listing regulation is precluded by other higher priority listing activities. The Texas golden gladecress and the Neches River rose-mallow were included in subsequent annual Candidate Notices of Reviews through 2004 (64 FR 57533, October 25, 1999; 66 FR 54808, October 30, 2001; 67 FR 40657, June 13, 2002; and 69 FR 24876, May 4, 2004). A petition to list Texas golden gladecress and the Neches River rose-mallow was received on May 11, 2004, but contained no new information, and we continued to include both species in all annual Candidate Notices of Review between 2005 and 2011 (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; and 76 FR 66370, October 26, 2011). In 2000, Texas golden gladecress' listing priority number was increased from 5 to 2 in accordance with our priority guidance published on September 21, 1983 (48 FR 43098). A listing priority of 2 reflects a species with threats that are both imminent and high in magnitude. In 2010, Neches River rose-mallow's listing priority number was also increased from 5 to 2. It is our intent to discuss below only those topics directly relevant to the proposed listing of the Texas golden gladecress as an endangered species and Neches River rose-mallow as a threatened species in this section of the proposed rule.
Background
This document contains proposed rules to list Texas golden gladecress as an endangered species and Neches River rose-mallow as a threatened species and to propose critical habitat for each species. The document is structured to address the taxa separately under each of the sectional headings that follow.
Species Information
Texas Golden Gladecress
Taxonomy and Description
Texas golden gladecress is a small, annual, herbaceous plant belonging to the mustard family (Brassicaceae). Dr. M.C. Leavenworth, an Army physician, first collected the taxon in Choctaw County, Oklahoma, in 1835, and the specimens were later described as a new species,
Leavenworthia aurea,
by Torrey (Mahler 1981, pp. 76-77). From 1836 to 1837, Leavenworth collected similar specimens near the present-day town of San Augustine, San Augustine County, Texas, and these were also identified as
L. aurea.
Later collections of the plant in the San Augustine area were made by E.J. Palmer (1915 and 1918), D.S. and H.B. Correll (1961 to 1962) as cited by Mahler (1981, pp. 83), and populations in this area were studied and mapped by George and Nixon (1990, pp. 117-127) between 1979 to 1980. W.H. Mahler studied the collected specimens and their habitat, and described the Texas plants as a new species,
Leavenworthia texana
(Mahler 1987, pp. 239-242), based on differences in morphological characteristics of flowers and leaves, and in chromosome number, between the Oklahoma and Texas plants (Mahler 1987, pp. 239-242).
According to Mahler (1987, p. 240), Texas golden gladecress flower petals were a brighter, deeper yellow than those of
L. aurea;
and the petals were egg-shaped and flat instead of being broad and notched. The
L. texana
had wider-than-long terminal leaf segments that were usually distinctly lobed while
L. aurea'
s terminal leaves were essentially unlobed, flat, and more circular. Texas plants had a chromosome number of 2n = 22 (E.S. Nixon, pers. comm. in Mahler 1987, pp. 239, 241) while the Oklahoma
L. aurea
had 2n = 48 (Rollins 1963, pp. 9-11; Beck
et al.
2006, p. 156). We are aware that a recently completed monograph of the genus may have taxonomic implications for the Texas and Oklahoma
Leavenworthia
species in the future, but several questions, including the differences in chromosome number, remain unresolved and no supporting information that would change the current status of Texas golden gladecress has been published to date (Poole 2011a, pers. comm.).
Texas golden gladecress is a weakly rooted, glabrous (smooth, glossy), winter annual (completes its life cycle in 1 year). Texas golden gladecress is small in stature, less than 3.9 inches (in) (10 centimeters (cm)) in height, making it difficult to find except during flowering or when it bears fruit. The leaves are 0.8-3.1 in (2-8 cm) long and 0.4-0.6 in (1-1.5 millimeters (mm)) wide, forming rosettes at the base of the plant. Terminal leaf segments are wider-than-long, and usually distinctly lobed, with angular teeth. Flowers are bright yellow and borne on scapes (leafless flowering stems or stalks arising from the ground) that are 1.2-3.5 in (3-9 cm) long early in the flowering season. Later in the season, the flowers occur on unbranched flower clusters that come off a single central stem from which the individual flowers grow on small stalks, at intervals. The four petals are bright golden-yellow with a slightly darker base, narrowly obovate (tongue-shaped), 0.3-0.4 in (7-10 mm) long and 0.1-0.2 (3.5-5 mm) wide. The fruit is a slender seed capsule, known as a silique, with a length (0.6-1.2 in (15-30 mm)) that is more than twice its width (0.08-0.22 in (2-5.5 mm)) and that contains 5-11 flattened, circular or spherically shaped seeds. The description above was drawn from Poole
et al.
(2007, p. 286), who adapted it from others.
Habitat
Texas golden gladecress occurs within the Pineywoods natural region of easternmost Texas, within the Gulf Coastal Plain Physiographic Region. The region is defined by pine-dominated forests or woodlands interspersed with bottomland, mesic slope and bald cypress-tupelo swamp forests. Many of the rare plants of the Pineywoods region, including the gladecress and the federally endangered
Physaria pallida
(white bladderpod) are found in small-scale plant communities tied to “geologic and hydrologic conditions that are themselves rather rare on the landscape” (Poole
et al.
2007, p. 6).
The Texas golden gladecress is endemic to glade habitats in northern San Augustine and northwest Sabine Counties, Texas, and is a habitat specialist, occurring only on outcrops of the Weches Geologic Formation (Mahler 1987, p. 240; George and Nixon 1990, p. 120; Poole
et al.
2007, pp. 286-287). The gladecress grows only in glades on shallow, calcium-rich soils that are wet
in winter and spring. These occur on ironstone (glauconite or green-stone) outcrops (Poole
et al.
2007, p. 286).
All species within the small genus
Leavenworthia
share an adaptation to glade habitats that have unique physical characteristics, the most important being a combination of shallow soil depth and high calcium content (dolomitic limestone or otherwise calcareous soils) where the soil layers have been deposited in such a manner that they maintain temporary high-moisture content at or very near the surface (Rollins 1963, pp. 4-6). Typically, only a few inches of soil overlie the bedrock, or, in spots, the soil may be almost lacking and the surface barren. The glade habitats that support all
Leavenworthia
species are extremely wet during the late winter and early spring and then dry to the point of being parched in summer (Rollins 1963, p. 5). These glades can vary in size from as small as a few meters to larger than 0.37 miles
2
(mi
2
) (1 kilometer
2
(km
2
)) and are characterized as having an open, sunny aspect (lacking canopy) (Quarterman 1950, p. 1; Rollins 1963, p. 5). The landscape position of the glades may also play a role in assuring the cyclic moisture regime required by glade vegetation communities.
The Weches Geologic Formation consists of bands of ancient marine sediments deposited in a line roughly parallel to the Gulf of Mexico, running from Sabine to Frio Counties, Texas. A layer of glauconite clay is either exposed at the surface or covered by a thin layer of calcareous (calcium-containing) sediment measuring as deep as 20 in (50 cm) (George and Nixon 1990, pp. 117-118). Glauconite is a characteristic mineral of marine depositional environments, presenting a greenish color when initially exposed to the atmosphere, and later turning red (Davis 1966, pp. 17-18; Nemec 1996, p. 7). The area of the Weches outcrops in San Augustine County is referred to as the “redlands” (Ritter 2011b, pers. comm.). The glauconite is very friable (crumbly) and has low resistance to weathering (Geocaching.com 2010, p. 5). The soils overlying the clay layer are typically rocky and shallow (George 1987, p. 3) and at all Texas golden gladecress sites are classified within the Nacogdoches, Trawick, or Bub soils series (USDA 2009, entire).
Weches outcrops occur in a band averaging 5 miles (mi) (8 kilometers (km)) in width that parallels Texas State Highway (SH) 21 through northern San Augustine and northwestern Sabine Counties (Sellards
et al.
1932 in Diggs
et al.
2006, p. 56). It has been deeply dissected by erosion that created islands of thin, loamy, alkaline soils (pH 7-8), within the normally deep, sandy, acidic soils (pH 4-5) of the Pineywoods region. The glauconite layer of the Weches Formation is fairly impermeable to water, producing saturated, thin upper soils in late fall through spring, that dry out and harden during summer months (George 1987, pp. 2-4; Bezanson 2000 in Diggs
et al.
2006, p. 56). Down-slope seepage across the Weches terraces may also be important to maintain the hydrology required by the gladecress (Singhurst 2003, pers. comm.). The cyclic moisture regime and the alkalinity of the soils produce conditions unique to the Weches outcrops. Certain plants, such as the Texas golden gladecress, have evolved to live within these specialized geologic formations (Mahler 1987, p. 240; George and Nixon 1990, pp. 120-122).
Biology
The Texas golden gladecress occurs in open, sunny, herbaceous-dominated plant communities in Weches glades, in some areas that also support the white bladderpod (Bridges 1988, p. II-7, II-35, and II-35 supplement). Unlike the white bladderpod, which can grow throughout the glade, the gladecress is restricted to the outcrop rock faces within the glades where it occurs (Nemec 1996, p. 8).
As is true of other
Leavenworthia
species (Rollins 1963, p. 6), Texas golden gladecress seeds germinate during fall rains and the plants overwinter as small, tap-rooted rosettes. Flowering begins in February and continues into March, and sometimes as late as April, depending on annual weather conditions. Rollins (1963, p. 6) noted that the blooming period of
Leavenworthia
varied according to the temperature, moisture, and severity of winter freezes. Fruit production is generally seen from March into April. The plants respond to drying of the soil by dropping seed and withering away, usually in April and May (Singhurst 2011b, pers. comm.). By summer months, gladecress plants are dead, replaced by other low-growing species such as
Sedum pulchellum
(stonecrop),
Portulaca oleracea
(common purslane),
Phemeranthus parviflorus
(sunbright), and
Elocharis occulata
(limestone spikerush) (Singhurst 2012e, pers. comm.). Although seed dispersal has not been studied in Texas golden gladecress, observations indicate that seeds fall within 6-8 in (15-20 cm) of the parent plant (Singhurst 2011c, pers. comm.).
Little is known about the gladecress' seed bank as this aspect of life history has not been researched. The species did reappear at two sites where it was believed lost due to habitat degradation. A population location, the Geneva Site in Sabine County (see Table 1), was bulldozed in late March 1999, one week after flowering plants were counted—the site was subsequently described by the surveyor as “lost or destroyed” (Turner 1999, pers. comm.). However, plants were found again at this site in 2003 and continued to emerge in succeeding years. At a second site in San Augustine County (Chapel Hill Site, see Table 1), a thick growth of the invasive, nonnative shrub,
Rosa bracteata
(Macartney rose) was removed in 1995. Post-brush removal, the gladecress reappeared after not having been seen for the previous 10 years (Nemec 1996, p. 1). The species' reappearance after these habitat alterations suggests a persistent seed bank, although there have been no formal studies to verify this hypothesis.
Rare plants often have adaptations such as early blooming, extended flowering, or mixed-mating systems that allow them to persist in small populations (Brigham 2003, p. 61). The Texas golden gladecress is believed to be self-compatible and able to self-fertilize (Rollins 1963, p. 19; Beck
et al.
2006, p. 153). The species may have evolved for self-fertilization when conditions are not favorable for insect-vectored pollination, lessening the species' dependence on pollinators for cross-pollination and survival and potentially making the species more resilient under conditions of small, geographically separated populations. Rollins (1963, pp. 41-47) speculated that species in the genus
Leavenworthia
evolved from a self-incompatible original ancestor to self-compatibility in some species to persist with a diminishing overlap in seasonality of adequate moisture in glade habitats versus availability of insect pollinators (e.g., as the southeastern part of the U.S. warmed, the required moisture levels for germination and flowering became more restricted to winter months when insect availability was lower). This could help to enhance the species' persistence, at least in the short term, in a fragmented landscape where habitat patches may be so distant from one another as to preclude pollinators' movements between them. The presence of other flowering plants at gladecress sites could help to attract and maintain a reservoir of pollinators, thereby increasing the chances for the gladecress to be cross-pollinated. This would benefit the species by potentially providing a higher level of genetic diversity.
Distribution and Status
Texas golden gladecress is known from eight locations, including one introduced population, all within a narrow zone that parallels SH 21 in San Augustine, Sabine, and Nacogdoches Counties (Texas Natural Diversity Database (TXNDD) 2012b). Table 1 (below) summarizes the location information for Texas golden gladecress populations (taken from the TXNDD 2012b). Based on known population locations, taken from the TXNDD element occurrence records from 1974-1988, the Weches Glades of San Augustine County appear to be the center of the species' distribution; to date all but one of the naturally occurring populations were found in this area, with the other naturally occurring population in Sabine County. One population was successfully introduced into Nacogdoches County. All locations (historic and extant) occur primarily on privately owned land, although the plants do extend onto the Texas Department of Transportation (TxDOT) right-of-way (ROW) at two sites: Geneva Site and Caney Creek Glades Site 1 (CCG 1).
Table 1—Location and Status of Texas Golden Gladecress Populations
County
Population
designation
Status
Historic site description
Land owner
San Augustine
Caney Creek Glade Site 1
Extant
Described by The Nature Conservancy as approx. 1 ac (0.4 ha) site; by 2001 was less than 100 ft² (9 m²)
Private & State ROW.
San Augustine
Chapel Hill (aka Tiger Creek)
Extant
Tract on which gladecress was found was less than 0.25 ac (0.1 ha)
Private.
Sabine
Geneva
Extant
Size of site was approx. 100 ft² (9 m²)
Private & State ROW.
Nacogdoches
Simpson Farms (Introduced Population)
Extant through 2009. Site was eradicated by pipeline in 2011
Population approx. 200 ft² (18 m²) in size
Private.
San Augustine
Caney Creek Glade Site 7
Status unknown. Possibly extant—not accessible in last 24 years
Small population; locally abundant in very small area
Private.
San Augustine
Caney Creek Glade Site 2
Site is now excavated pits
Site was approx. 3 ac (1.21ha)
Private.
San Augustine
Caney Creek Glade Site 6
Site is now excavated pits. Possibility that some habitat and plants remain on adjacent, unquarried land
Multiple tracts totaling ~ 10 ac. Sites 6, 7 and 8 in different areas on these tracts. Site 6 was the largest known population—thousands of plants
Private.
San Augustine
Caney Creek Glade Site 8
Site lost to excavated pits
Very small population on a degraded outcrop
Private.
Four Texas golden gladecress populations (CCG 1, Chapel Hill, Geneva, and Simpson Farms) were present through 2009—the last year that the plants were surveyed (Singhurst 2011a, pers. comm.). In October 2011, Service and TPWD biologists visited all four known locations and found that the plants and habitat at the introduced site in Nacogdoches County (Simpson Farms) had been removed by a recent pipeline installation. The habitat was still intact at the other three locations (Cobb 2011, pers. comm.), and we assume that plants still occupy these sites.
Three San Augustine County occurrences (CCG Sites 2, 6, and 8) were believed extirpated, at least in large part, by construction of glauconite mines (open pits) beginning in the late 1990's. These occurrences may have been part of a much larger glade complex, referred to as the Caney Creek Glade Complex, that included the Caney Creek Glade Sites 1, 2, 6, 7, and 8. These five occurrences were located within an area extending out to 1.5 mi (2.41 km) to the east of the town of San Augustine (TXNDD 2012b, unpaginated). In 1987, the CCG Site 6 was described as having Texas golden gladecress plants “in the thousands” (TXNDD 2012b, unpaginated). Access to these three privately owned sites is prohibited; therefore, we cannot ascertain whether any plants or their habitat are still present on the peripheries of the mined areas.
The CCG Site 7 was last visited in 1988 (TXNDD 2012b, unpaginated). There were no further site visits due to lack of access to the privately owned land. Satellite images taken as recently as 2008 show this population site has not been altered by construction or quarrying (mining), but the open glade appearance at this site has changed to one of dense growth of woody vegetation, so it is unknown whether the plants still occur at the site.
Table 2 presents estimates for extant Texas golden gladecress populations between 1999 and 2009 (USFWS 2012, p. 4). The total number of plants seen in 2009 was 1,108. The largest population, consisting of 721 plants, was at the introduced site in Nacogdoches County, a site that was lost in 2011 when a pipeline route was constructed directly through it. This represents a loss of 65 percent of the known plants. After 2009, approximately 400 plants in 3 populations were all that remained of this species. The number of gladecress plants fluctuated widely from year to year, likely due to differences in precipitation levels between years. The gladecress is dependent on fall and winter rain to saturate the sediment and produce the seeps and pooling it requires, and drought conditions were noted to have a significant negative effect on reproduction, (Turner 2000, p. 1) as seen in the drought years of 1999-2000 (Texas Water Resources Institute 2011, unpaginated) when the Chapel Hill site decreased from 91 to 67 plants and the CCG Site 1 decreased from 490 to 96 plants (USFWS 2010, p. 5).
Table 2—Population Estimates for Texas Golden Gladecress at Monitored Sites
Year
Chapel Hill
CCG #1
Geneva
Simpson Farms
1999
91
490
319
* NS
2000
67
96
NS
NS
2001
96
520
NS
270
2002
NS
NS
NS
NS
2003
42
NS
57
57
2004
NS
NS
NS
NS
2005
40-50
0
54
2,873
2006
NS
NS
200
NS
2007
200
NS
1,000
1,000
2008
9
NS
49
NS
2009
98
29
260
721
* NS—Not surveyed.
Singhurst (2011a, pers. comm.) referred to the difficulty of trying to determine population trends for the Texas golden gladecress due to the lack of comprehensive numbers for the species. He attributed this data gap to variation in surveyors and their techniques, the inability to see gladecress plants under invasive brush, lack of access to multiple sites, and the fluctuation in plant numbers associated with moisture conditions. Nevertheless, despite these limitations, it is evident that there are few remaining populations and that the overall numbers of existing plants are fluctuating. For example, a decrease in plant numbers in 2009 was likely due to drought; however, following significant rains in late fall 2011 and early winter 2012, Singhurst (2012f, pers. comm.) noted higher numbers of plants than the 2009 counts at Geneva, Chapel Hill, and CCG Site 1.
Most of the known populations, historic and extant, were and are restricted to small areas (see Table 1). For example, in San Augustine County, the Chapel Hill site is less than 0.2 acres (ac) (0.1 hectare (ha)) in size and lies between a pasture fence and gravel road southwest of SH 21. The area of the plants at the CCG Site 1 is less than 100 ft
2
(9 m
2
) in size, on the side of Sunrise Road south of SH 21. In Sabine County, the plants at the Geneva site occupy approximately 100 ft
2
(9 m
2
) adjacent to, and west of, SH 21, south of Geneva. The total area occupied by the plants at the remaining three sites covers less than 1.2 ac (0.5 ha). Area sizes for gladecress occurrences were taken from the TXNDD element of occurrence records.
Although no new populations of Texas golden gladecress have been found since the late 1980s, there is potential for more gladecress to exist across the Weches Glades Region. Known populations all occur close to roads suggesting that most searches for the species were nearby to public road access. All known occurrences are on private property, as is all remaining habitat; therefore, surveys cannot be conducted without landowner permission. Effective identification of suitable habitat is needed to survey for new populations. Even in areas of potential Weches Glades, as identified using Geographic Systems Information (GIS) data, including aerial, geologic, and hydrologic data sources, the habitat may not contain Texas golden gladecress populations. Between 1999 and 2003, The Nature Conservancy (TNC) used these tools to identify 44 potential sites of gladecress and white bladderpod occurrence in the San Augustine Glades. The TNC was granted access to 14 of the 44 sites, but found little Weches habitat, and no new gladecress or bladderpod sites (Turner 2003 in USFWS 2010b, p. 3).
Neches River rose-mallow
Taxonomy and Description
Hibiscus dasycalyx
(the rose-mallow) (Blake) is a nonwoody perennial (plant that grows year after year) in the Malvaceae (mallow) family that grows 1.9-7.5 feet (ft) (0.6-2.3 meters (m)) tall (Correll and Johnston 1979, p. 1030). Leaves are alternate and simple, generally t-shaped and deeply three-lobed with petioles (leaf stalks) 1.1-1.9 in (3-5 cm) long (Correll and Johnston 1979, p. 1030). This rose-mallow generally produces six or seven creamy white flowers (rarely pink) singularly on branches flowering between June and August (Poole
et al.
2007, p. 265), sometimes into late October depending on water availability during springtime inundations (Warnock 1995, p. 20; Center for Plant Conservation 2011,
http://www.centerforplantconservation.org
/). Large and numerous stamens are monodelphous, forming a tube that is united with the base of the petals (Klips 1999, p. 270).
The rose-mallow was first collected by Ivan Shiller on June 23, 1955, at the type locality at Hwy 204 (also referred to as Apple Springs), Trinity County, Texas, and was later identified as a distinct species (Correll and Johnston 1979, pp. 1030-1031). Blake (1958, p. 277) determined that the rose-mallow was different from the closely related
Hibiscus laevis
(halberdleaf rose-mallow) by examining specimens from the type locality. Gould (1975), Nixon (1985), Hatch
et al.
(1990), Johnston (1990), and Fryxell (Warnock 1995, pp. 1-2; Poole 2002, pers. comm.) all recognized the rose-mallow as a distinct species.
Two similar-looking
Hibiscus
species,
H. laevis
and
H. moscheutos
(crimsoneyed rose-mallow) are aquatic species documented in areas where the rose-mallow occurs. A morphological distinction between these
Hibiscus
species of East Texas and the rose-mallow is the species' notably hairy calyx (Warnock 1995, p. 5). All three of these species have a similar general appearance, but can be separated based on a comparison of external characteristics including leaf structure, and degree of pubescence (fine hairs) on the calyx, leaves, capsule (dry fruit), or seeds (Correll and Correll 1975, p. 1118; Blanchard 1976, p. 5; Warnock 1995, p. 4). Geographically, these three species can be found within similar habitats, but the halberdleaf and the crimsoneyed rose-mallows prefer deeper water and are found along edges of major rivers and streams (Blanchard 1976, pp. 10-14; Poole 2011b, pers. comm.), compared with the rose-mallow, which is found in side channels and floodplains of major river drainages. Based on the available information on the species morphology, biology, and habitat-specific needs, we conclude that the rose-mallow is a valid taxon.
Habitat
The rose-mallow is endemic to relatively open habitat (Kennedy and Poole 1990, p. 11) of the Pineywoods (or Timber belt) of East Texas (Gould 1975, p. 1; Correll and Johnston 1979, p. 1030), within Cherokee, Houston, and Trinity Counties and has been introduced into Nacogdoches and Harrison Counties. Shortleaf/loblolly pine-hardwood forests dominate the habitat with portions of suitable habitat extending into longleaf pine (
Pinus palustrus
) and loblolly pine forest (
Pinus taeda
) (Telfair 1983, p. 28; Diggs
et al.
2006, p. 95). The common native woody and herbaceous plant associates are listed in Table 3 (Warnock 1995, pp. 14-15; Poole
et. al
2007, pp. 264-265).
Table 3—Native Plant Associates of Neches River Rose-Mallow
Scientific name
Common name
Native Woody Plant Associates
Carya aquatic
water hickory.
Cephalanthus occidentalis
common buttonbush.
Celtis laevigata
var.
laevigata
sugar berry.
Fraxinus
sp.
ash.
Quercus lyrata
overcup oak.
Q. nigra
wateroak.
Liquidambar styraciflua
sweetgum.
Salix nigra
black willow.
Native Herbaceous Plant Associates
Boehmeria cylindrica
smallspike false nettle.
Brunnichia ovate
buckwheat vine.
Carex lupulina
common hop sedge.
Chasmanthium sessilifolium
longleaf woodoats.
Diodia virginiana
Virginia buttonweed.
Eichhornia crassipes
water hyacinth.
Heliotropium indicum
Indian heliotrope.
H. moscheutos
crimsoneyed rose-mallow.
H. laevis
halberdleaf rose-mallow.
Hydrolea ovate
ovate false fiddleleaf.
Hydrocotyle ranunculoides
floating pennywort.
Juncus effuses
common rush.
Ludwigia leptocarpa
anglestem primrose-willow.
Nuphar lutea
yellow pond-lily.
Phanopyrum gymnocarpon
Savannah-panicgrass.
Panicum ridgulum
redtop panicgrass.
Pluchea foetida
stinking camphorweed.
Polygonum hydropiperoides
swamp smartweed.
Pontederia cordata
pickerelweed.
Rhynchospora corniculata
shortbristle horned beaksedge.
Scirpus cyperinus
woolgrass.
Thalia dealbata
powdery alligator-flag.
Trachelospermum difforme
climbing dogbane.
Sites where the rose mallow have been found have been described as sloughs, oxbows, terraces, and sand bars. Sites include low areas (Warnock 1995, p. 13) within the Neches River basin and Mud and Tantabogue Creek basins, with soils that are classified generically as hydric alluvials, or water-saturated soils, of the Inceptisol or Entisol orders (Diggs
et al.
2006, pp. 46, 79) that remain flooded or frequently flood. The U.S. Department of Agriculture's (USDA) Natural Resource Conservation Service (NRCS) completed soils surveys for all counties with known occurrences of the rose-mallow, and the associated soils are frequently flooded clay loams. Sites are both perennial and intermittent wetlands with water levels between sites varying due to their proximity to water, amount of rainfall, and floodwaters. Intermittent wetlands are inundated during the winter months but become dry during the summer months (Warnock 1995, p. 11). Flowing water is required for seed dispersal downstream (Warnock 1995, p. 20; Scott 1997, p. 8; Reeves 2008, p. 3). Rivers of East Texas tend to overflow onto banks and floodplains (Diggs
et al.
2006, p. 78), especially during the rainy season, thereby dispersing seed. Research has not been done to identify methods of seed dispersal upstream; however, avian species may facilitate this process.
Biology
The rose-mallow is a perennial that dies back to the ground every year and resprouts from the base; however, still maintaining aboveground stems. Longevity of the species is unknown but it may be long-lived. Cross-pollination occurs (Blanchard 1976, p. 38) within the rose-mallow populations and the species has high reproductive potential (fecundity). The number of flowers and fruits per plant were documented during the TPWD's annual monitoring of the rose-mallow along State Highway (SH) ROWs. The species produced an average of 50 fruits per plant, but seed viability and survivorship are not known (Poole 2012a, pers. comm.). An open canopy (Warnock 1995, pp. 11, 13) and sunlight are needed for flowers to bloom, and the blooming period may only last 1 day (Snow and Spira 1993, p. 160).
Potential pollinators of the rose-mallow may include but are not limited to, the common bumblebee (
Bombus pensylvanicus
), Hibiscus bee (
Ptilothrix bombiformis
), moths, and the scentless plant bug
Niesthrea louisianica
(Klips 1995, p. 1471; Warnock 1995, p. 20; Warriner 2011, pers. comm.). Both
H. laevis
and
H. moscheutos
are pollinated by common bumblebees and the Hibiscus bee (Snow and Spira 1993, p. 160; Klips 1999, p. 270). The solitary Hibiscus bee prefers gently sloping or flat areas with sandy or sandy-loam soils for nesting areas (Vaughan
et al.
2007, pp. 25-26; Black
et al.
2009, p. 12), and female bees will excavate nest cavities in elevated, hard packed, dirt roadways or levees near stands of
Hibiscus
(in this case
H. palustris
) and standing water (Rust 1980, p. 427). Members of the genus
Bombus
(family Apidae) are social bees, predominantly found in temperate zones, nesting underground (Evans
et al.,
2008, p. 6) in sandy soils (Cane 1991, p. 407). Bumblebees nest in small cavities, often underground in abandoned rodent nests, grass (Black
et al.
2009, p. 12), or in open, grassy habitat (Warriner 2012a,
pers. comm.). Other aboveground-nesting bees that may potentially pollinate the rose-mallow may include carpenter, mason, and leaf cutter bees that nest in dead snags or twigs or standing dead wood (Warriner 2012a, pers. comm.). Maximum foraging distances of solitary and social bee species are 492 to 1,968 ft (150 to 600 m) (Gathrmann and Tscharntke 2002, p. 762) and 263 to 5,413 ft (80 to 1,650 m) (Walther-Hellwig and Frankl 2000, p. 244), respectively. The scentless plant bug is a member of the
Rhopalidae
family found specifically in association with various members of the Malvaceae family. This species is known to deposit eggs on both the vegetative and reproductive parts of mallow plants (Spencer 1988, p. 421). Holes have been eaten in floral parts of rose-mallow plants suggesting that the scentless plant bug may be a pollinator as well as a consumer of the rose-mallow.
Natural fires occur every 1 to 3 years in East Texas (Landers
et al.
1990, p. 136; Landers 1991, p. 73) and control the overgrowth of longleaf and loblolly pine, as well as nonnative species; humans later used fire to suppress overgrowth. Fire suppression allows for sweetgum (
Liquidambar styraciflua
), oaks (
Quercus
sp.), hickories (
Carya
sp.), common persimmon (
Diospyros virginiana
), and southern magnolia (
Magnolia grandiflora
) to invade the natural pine forests (Daubenmire 1990, p. 341; Gilliam and Platt 1999, p. 22), and reduce the open canopy needed by the rose-mallow. Lack of fire increases the opportunity for nonnative species, such as chinese tallow (
Triadica sebifera
), to invade these sites.
Distribution and Status
The natural geographic range of the rose-mallow is within Trinity, Houston, Harrison, and Cherokee Counties, Texas, on State highway (SH) ROWs and on private and Federal lands. However, the species has been introduced outside of the known geographic range in Nacogdoches County on private land (Mill Creek). In addition, populations of rose-mallow have been introduced within their natural geographic range on Federal lands. In total, there are 12 occurrences of rose-mallow (see Table 4). Eleven of these are within the known geographic range, and, as of October 2011, are occupied by the rose-mallow. The rose-mallow plants within the SH 230 ROW have not been seen since 2002, and the site is considered extirpated.
Table 4—Population Estimates for Known Rose-Mallow Occurrences
Site
County
First and last observation
Plant estimates
1. Compartment 55, Davy Crockett National Forest (NF)
Houston
2000; 2011
1000 in 2000, 750 in 2002, 750 in 2010, 400-500 in Oct. 2011.
2. Compartment 16, Davy Crockett NF (introduced)
Houston
2000; 2011
450 in 2000, 115 in 2002, 78 in 2003, 50 in 2006, 90 in 2010, 43 in 2011.
3. Compartment 11, Davy Crockett NF (introduced)
Houston
2004; 2011
200 in 2004, 10 in 2006, 7 in 2010, 10 in 2011.
4. Compartment 20, Davy Crockett NF (introduced)
Houston
2000; 2011
200-250 in 2000, 70 in 2002, 182 in 2002, 350 in 2006, 120 in 2010, 101 in 2011.
5. SH 94 ROW/Boggy Slough
Trinity
1955; 2011
100+ in 1968, 50 in 1986, 50 in 1987, 13 in 1988, 7-9 in 1991, 2 in 1992, 27 in 1993, 38 in 1994, 41 in 1995, 16 in 1996, 15 and 20 on private land in 1997, 13 in 1998, 49 in 1999, 17 in 2000, 15 and 300+ on private land in 2001, 20 in 2002, 20 and 0 on private land in 2005, 35 along powerline in 2007, 128 along ROW in 2011.
6. SH 204 ROW/Mud Creek
Cherokee
1992; 2011
1 in 1992, 1 in 1993-1996, 75 in 1997, 1 in 1998, 2 in 1999, 1 in 2000, 5 in 2001, 1 in 2002, 7, 6, 3, and 30 respectively at four new subpopulations in 2010, 20 in 2011.
7. SH 230 ROW
Houston
1978; 2002
50 in 1991, 58 in 1993, 38 in 1994, 1 in 1995, 2 in 1996, 6 in 1997, 8-13 in 1998, 14 in 1999, 8 in 2000, 4 in 2001, 12 in Sept. 2002, none in Oct. 2002, none in 2003, 2004, 2005, and 2011.
8. Lovelady
Houston
2011
50-70 in 1991, 7 in 1992, 58 in 1993, several hundred in 2001, 400 in 2002, 539 in 2011.
9. Mill Creek Gardens (introduced)
Nacogdoches
1995; 2011
96 in 1995, hundreds in Oct. 2011.
10. Harrison site
Harrison
Not observed after 1980
Herbarium specimen was recently confirmed as
H. dasycalyx,
but site has not been observed since 1980.
11. Champion site
Trinity
1996; 2001
Hundreds in 1997, 300-400 in 2001.
12. Camp Olympia
Trinity
1977; 1992
No estimates.
Populations along SH ROWs include Hwy 94 in Trinity County, collected in 1955 (Blake 1958, p. 277); Hwy 204 in Cherokee County, first observed in 1992; and Hwy 230 in Houston County, first observed in 1978. The TPWD performed annual SH ROW monitoring along Hwy 94 from 1993 thru 2001 (Poole, 2001, p. 1); along Hwy 204 from 1993 thru 2003 (Poole 2001, p. 1; TXNDD 2012a, pp. 20-28); and along Hwy 230 from 1993 thru 2001 (Poole 2001, p. 1). These three ROW populations are separated from one another and are considered distinct. However, the Boggy Slough site consists of several scattered rose-mallow subpopulations that are located in close proximity to one another. Boggy Slough subpopulations and the SH 94 ROW population are separated by no more than a distance of 1.0 km (3, 280 ft), and these two sites likely constitute a single, larger population, sharing pollinators, and exchanging genetic material (NatureServe 2004, p. 6; Poole 2011c, p. 2). Therefore, in Table 4, they are combined and represented as a single location.
Adjacent lands to the SH 230 ROW were purchased by the Texas Land Conservancy (TLC) in 2004 (TLC 2011,
http://www.texaslandconservancy.org)
. The rose-mallow plants in this site, referred to as Lovelady, are part of a population that included the rose-mallow plants in the SH 230 ROW. The rose-mallow plants within the SH 230 ROW have not been observed since 2002, and the site is considered
extirpated (TXNDD 2012a, pp. 61-67). The Lovelady site was recently surveyed in 2011, and although 539 plants were found, most were in notably poor condition, being much shorter in stature because of the drought and herbivory (Poole 2012b, pers. comm.; TXNDD 2012a, pp. 14-19). The estimates of rose-mallow displayed in Table 4 show wide variations in plant numbers. Some of this variation is due to incomplete counts at the sites, in other words, only a portion of the population was counted. Meaningful trends cannot be derived from these population estimates.
Although annual monitoring of the ROW sites was discontinued in the early 2000s, TPWD visited all of the ROW sites in October 2011. In the past, along SH 204, several subpopulations existed along multiple portions of the ROW; however, several of these subpopulations were gone in 2011. The recent drought conditions have allowed surveyors to count rose-mallow plants in parts of sites that were not accessible in the past because the sites were too wet. The increase in numbers of plants at some of the ROW sites may be partially attributed to this.
The Davy Crockett National Forest (NF), Houston County, Texas, contains four extant sites of the rose-mallow, three introduced and one natural. The one natural population is found in compartment 55 located west of the Neches River. This site is considered the most robust of all known extant populations (Poole 2011c, p. 3) and is almost entirely unaltered from its originally observed state as a seasonally wet flatwood pond, with vegetation being distinctly zoned (TXNDD 2012a, p. 29). The three introduced populations are located in compartment 16, which started with 450 plants (Davis 2000, pers. comm.; McCormick 2002, p. 1; USFWS 2000, p. 3), compartment 20 with 200-250 plants (Davis 2000, pers. comm.; McCormick 2002, p. 2; USFWS 2000, p. 3), and compartment 11 with about 200 plants (Nemec 2005, pers. comm.). The populations in compartments 16 and 20 were introduced in 2000, while the population in compartment 11 was introduced in 2004 (USFWS 2007, p. 6). All four of the Davy Crockett NF sites were censused in October 2011 by the Service and TPWD, and all of the introduced sites on the Davy Crockett National Forest have declined dramatically.
The four remaining rose-mallow sites have had sporadic monitoring or have not been visited in recent years. In 1995, Stephen F. Austin State University (SFASU) Mast Arboretum planted 96 rose-mallow plants into a site at Mill Creek Gardens, Nacogdoches County (Scott 1997, pp. 6-7). A conservation easement was placed on this land, and now the site is managed by the Arboretum. Rose-mallow plants at this site were observed in 1997, 1998, 2001, 2009, and in 2011 (Creech 2011a, pers. comm.). The introduced plants appear to be doing well; however, nonnatives and native species are becoming more prevalent, and may compete with the rose-mallow (Creech 2011c, pers. comm.). A rose-mallow specimen collected on private lands in 1980 from Harrison County, Texas, was presumed to be a halberdleaf rose-mallow specimen; however, it has been recently confirmed (2011) to be the rose-mallow (Birnbaum 2011, pers. comm.; TXNDD 2012a, pp. 12-13). The Harrison County site has not been visited since 1980, but we presume that rose-mallow is extant at this site since we have no evidence that the species is extirpated. Two additional populations occur on private lands in Trinity County; the Camp Olympia and Champion sites, discovered in 1977 and 1996, respectively. The current status of rose-mallow on the Camp Olympia site is unknown since access has been denied. We consider this site to be extant because we have no evidence that it has been extirpated. The population on the Champion site was observed in 2011; plants were seen, but no plants counts were done.
Summary of Factors Affecting the Species
Section 4 of the Act (16 U.S.C. 1533), and its implementing regulations at 50 CFR part 424, set forth the procedures for adding species to the Federal Lists of Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of the Act, we may list a species based on any of the following five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; and (E) other natural or manmade factors affecting its continued existence. Listing actions may be warranted based on any of the above threat factors, singly or in combination. Each of these factors is discussed below.
Texas Golden Gladecress
A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range
Habitat loss and degradation have been the primary cause of decline in Texas golden gladecress during the last two decades. Permanent removal or destruction of habitat by quarrying and pipeline installation projects has eradicated several populations. Other habitat alterations that are occurring across the species' range, with potential to destroy or negatively alter gladecress' habitat, include construction of well pads, buildings, roads, and poultry production facilities. A historic and ongoing major threat to Texas golden gladecress' habitat is the invasion by nonnative and native shrubs and trees into the formerly open-sun, herbaceous, glade vegetation communities. Grazing has been implicated as a habitat threat because it is often associated with the encroachment of undesirable vegetation into the outcrop habitat, and may lead to trampling of plants. Agricultural herbicide use has some potential to damage emerging gladecress seedlings. Severe and extended periods of drought, anticipated to increase with projected changes in the climate, may negatively affect a given year's reproductive effort by Texas golden gladecress. These factors will be discussed in more detail below.
Glauconite Quarrying (Mining)
Glauconite, often called “blue rock” or “green rock” is used in San Augustine and Sabine Counties for road construction and maintenance by county road departments, the USDA Forest Service, and Louisiana Parishes (McGee 2011, pers. comm.). Glauconite has also been used by the oil and natural gas industry for roads and well pads, and demand by the oil and gas industry is high (McGee 2011, pers. comm.). Glauconite is also used as a component of fertilizer. A number of commercial glauconite quarries or mines were in production by 1997, and subsequent interest in its use grew because traditional pavement base materials historically used in this region (iron ore and limestone) were becoming harder to obtain and more expensive (Button and Little 1997, p. 14). A representative of one mining company with four quarries in the San Augustine and Sabine County area expressed an opinion that their mines were sustainable for 15 to 20 years at the current level of demand (McGee 2011, pers. comm.). We do not have a more quantified prediction regarding demand and existing supply; therefore, we
cannot accurately predict future quarry development. Selection of locations for glauconite quarries may target areas “where the glauconite can be seen on the surface” (outcrops), although quarries have also been dug on sites where the glauconite was not visible at the surface (McGee 2011, pers. comm.).
The Nature Conservancy (TNC) (2003, p. 9) noted that glauconite quarrying (mining) in glades destroys habitat and is a significant threat to the Texas golden gladecress. The majority of known habitat was excavated at three of the eight historical populations (CCG Sites 2, 6, and 8) between 1996 and 2011, resulting in open pits at the former habitat sites. The excavations removed all surface features required by the gladecress, as well as killing individual plants. Access to the Service has been denied at these sites, and we cannot determine if any habitat or plants remain on the periphery of the excavated quarries. The last recorded survey of plants at CCG Site 2 was on March 18, 1988, when the gladecress plants were described as growing on the sloping Weches outcrop that was brush-hogged and burned in 1988. Using available high-altitude photography taken between 1995 and 2009, supplemented with aerial photography from August 2010, it appears that the glade was still intact as of 1995-1996, but that a much larger area than the original population site was excavated by 2005. As of 2010, the entire population site and surrounding area looks to be two large, side-by-side pits or ponds. We assume that the populations are extirpated at this location.
The last information on plant numbers and conditions at the CCG Sites 6 and 8 was collected on March 19 and April 24, 1987. At that time, CCG Site 6 was recognized as the largest known viable population of Texas golden gladecress. At this site, the gladecress grew in a former pasture with thousands of fruiting plants in association with other native glade plants in shallow bedrock pockets. The CCG Site 8 consisted of a very small population on a degraded Weches outcrop, with scattered plants in fruit. Both elements of occurrence appeared to be eliminated by a large, open-pit quarry in which digging started after 1996, with the entire area being one large pit by 2009.
The outcrops may actually attract glauconite quarrying interests since the presence of an outcrop indicates that glauconite is close to the surface. Glauconite mining can occur throughout the range of Texas golden gladecress and has the potential to eradicate populations at sites where quarries are dug. There is no requirement for permits, no review of projects, and locations of future quarries are unknown. Based on our review of the scientific information, we conclude that excavation of pits for removal of glauconite, and associated glauconite quarrying activities, pose a threat to the gladecress across the species' range.
Natural Gas and Oil Exploration and Production
A principal threat to the habitat of Texas golden gladecress is the removal or destruction of habitat (outcrops and immediate surrounding land) by pipeline construction or from construction of buildings, well pads, or roads to access drilling sites directly over habitat. Natural gas pipeline installation requires trenching and clearing that can destroy all gladecress habitat and plants within the pipeline ROW. In addition to the destruction of habitat, excavation could conceivably alter the hydrology of gladecress sites if the lowered elevation of the excavation, or conversely, the increased ground elevation of a well pad or other structure, diminishes the amount of water that can move downslope over ground or through seeps. Adversely affecting the amount and timing of water delivery could render outcrop ledges uninhabitable for the species by interfering with the seeping or pooling action of water on which the species depends.
The loss of habitat and plants in the footprint of well pads and roads built for natural gas or oil exploration and production is a continuing threat because there is high potential to affect remaining glade habitat throughout the species' range. Numerous wells can be seen from SH 21 between the cities of Nacogdoches and San Augustine, with at least 30 wells visible along a 20-mile stretch of this road (Loos 2011, pers. comm.; Rodewald 2011, pers. comm.). The materials brought in to construct well pads and roads can directly cover habitat and plants, causing partial or total loss of populations. Excavations, as well as construction activities, that occur upslope of gladecress populations may act to impede movement of water downslope, thereby interfering with seeping and pooling of water needed by Texas golden gladecress. Concern about the extent of this threat is elevated due to our lack of information about potential gladecress populations across the Weches Glades where surveys for the species have not been undertaken, but where natural gas exploration and production is rapidly proceeding.
The entire known distribution of Texas golden gladecress is underlain by the Haynesville Shale formation (also known as the Haynesville/Bossier), recently recognized as a major natural gas source for the United States. The Haynesville Shale, located at a depth exceeding 11,000 ft (3,353 m), straddles the Texas-Louisiana border and almost 70 percent of its production is from wells located in Texas (Brathwaite 2009, p. 16). The Haynesville shale covers an area of approximately 9,000 square miles (23,310 square km). A June 2010 map shows the Haynesville Shale underlying the northwestern quarter of Sabine County, the entire northern half of San Augustine County, and the southeastern third of Nacogdoches County (Haynesville Shale Map 2010). Estimates of the natural gas contained in this formation's reserves indicate that it could sustain anticipated energy needs for well beyond the next several decades (
http://www.haynesvilleshalelandowners.org;
Brathwaite 2009, p. 16). Technological improvements in exploration (3-dimensional seismic surveys), drilling (horizontal wells), and well completion and stimulation (hydrologic fracturing) have enhanced the productive capability of natural gas shales throughout the United States, including the Haynesville Shale.
Natural gas exploration and production has been rapidly expanding within the Haynesville Shale, from the first significant production in 2005 to major development of the formation in 2009 (Brathwaite 2009, p. 16). Drilling activity over the entire Haynesville Shale peaked around 2009 or 2010 when approximately 200 drilling rigs were active. As of September 18, 2011, approximately 130 rigs were actively drilling; the slowdown being attributed to depressed natural gas prices (Murphy 2011a, p. 3). Even with natural gas prices down, most companies continue to drill one well per gas unit on the Haynesville Shale in order to maintain their leases (Murphy 2011a, p. 3). By September 2011, as many as 1,500 wells had been drilled with many more anticipated, along with perhaps another 10 years of active drilling on this formation (Murphyb 2011, pp. 2-3).
The Texas Railroad Commission's (RRCs) online maps (available at (
http://gis2.rrc.state.tx.us/public/startit.htm
) indicate that natural gas (and some crude oil) gathering and transmission pipelines are found throughout Nacogdoches County. In San Augustine County, the majority of existing pipelines are located in the area north of SH 21 and west of the town of San Augustine, an area of high glade
occurrence. To the east of San Augustine, there are fewer pipelines, but, of those that are located in this area, several are large gas transmission lines. One of these big transmission lines lies directly adjacent to the historic CCG Site 7. Sabine County has several major interstate pipelines, but fewer gathering and other transmission lines than the other two counties, and no pipelines near the Sabine County gladecress site (Texas Railroad Commission 2011).
The RRC regulates the oil and natural gas industry in the state of Texas. The RRC has detailed information on all existing pipelines, but the agency has no way to predict future routes for new pipelines or wells; they are limited to location data found within permit applications (Nunley 2011, pers. comm.). New pipelines, as well as ones for which routes are being determined, do not display on the RRC Web site, so although we are aware of the impact that pipeline excavations can have on Texas golden gladecress, we cannot tell where future pipelines may affect existing populations or suitable habitat.
Loss of gladecress habitat and plants is inevitable if pipelines are routed directly through population sites. Pipeline installation requires clearing of a path for the pipeline, cutting a trench in which to lay the pipe, recovering of the trench, and restoring the ground's surface. Clearing pipeline pathways eliminates obstacles to construction (NaturalGas.Org., p. 2), which may include the rocky outcrops supporting the Texas golden gladecress. Bulldozing the pipeline path likely permanently removes these rocky ledges and other features, along with the gladecress plants and seedbed. After the pipe is put into the ground and the trench covered with soil, elevations are restored and the surface is revegetated, generally using
Cynodon dactylon
(coastal bermudagrass) in this region (Rodewald 2011, pers. comm.). The Simpson Farms population, located 6 mi (9.7 km) east of the city of Nacogdoches, was eliminated by a natural gas pipeline that was installed sometime between August 2010 and October 2011 (date of installation determined from comparison of successive years of aerial photography). At this site, the pipeline ROW was approximately 75 ft (23 m) wide and the entire area formerly occupied by the gladecress was covered with deposited sediment or piles of cleared brush (Cobb 2011, pers. comm.). Given the degree of clearing of the ROW and the adjacent dirt work, the known extent of habitat is now gone and the entire population has likely been extirpated (Cobb 2011, pers. comm.). The Chapel Hill population may also be affected by future pipeline construction; the route for a future pipeline was being surveyed in October 2011 (Cobb 2011, pers. comm.). Although this pipeline does not directly cross the very small population site between the pasture fence and the road, it does lie parallel to, and just inside of, the fence line in a pasture where gladecress habitat does exist (Singhurst 2012c, pers. comm., Singhurst 2012f, pers. comm.).
The current trend over most natural gas shale formations is to drill multiple wells, when possible, and well pad sizes can vary accordingly. Well pad sizes in the San Augustine County area range from several acres to as large as 14 ac (5.67 ha), depending on the number of wells (Loos 2011, pers. comm.; Allen 2011b, pers. comm.). Although most oil and gas companies use existing roads, occasionally the companies need to build new roads, and in these cases the new routes may go through outcrop areas. The fill for pads and roads could cover portions of, or potentially entire, glade sites since some of the glades are so small. Placement of pads or roads upslope of gladecress sites may have the potential to affect downslope movement of water to outcrop sites (Ritter 2011b, pers. comm.).
In summary, the remaining populations of Texas golden gladecress and suitable habitat are within areas that are actively being drilled for natural gas. Plants and habitat have been destroyed by the construction of pipelines. The three remaining populations as well as suitable habitat are at risk of being destroyed by construction of natural gas and oil infrastructure (pipelines, well pads, metering stations, and roads) that continue to be constructed throughout the species' range. Exploration and production of natural gas and oil is anticipated to continue in this area for at least the next decade. Texas golden gladecress and its habitat may be directly impacted by the construction of pipelines and other infrastructure, and indirectly by altering the hydrology near occupied sites and suitable habitat. Based on our review of the scientific information, we conclude that natural gas and oil development is a threat to Texas golden gladecress.
Residential and Commercial Construction
Although residential and commercial construction was listed in the species' candidate assessments as a potential threat, there is no evidence that this type of disturbance has affected Texas golden gladecress populations. Historically, site selection for building homes and businesses in the town of San Augustine may have taken advantage of the open aspect of the glades—Leavenworth described the area in which he originally collected the species (vicinity of the town of San Augustine) as “prairies” (Bridges 1988, p. II-5). However, information about former glades in the area is lacking, as is documentation that the gladecress was present where buildings are currently located. Neither San Augustine nor Sabine Counties are experiencing rapid human population growth—San Augustine County saw a 0.9 percent decline in population from 8,946 to 8,865 between 2000 and 2010 while Sabine County had a modest increase of 3.5 percent (10,469 to 10,834) (U.S. Census Bureau 2010a,b), suggesting that residential and associated commercial development does not constitute a high level of threat to habitat throughout the species' range.
Proliferation of poultry farms was also listed as a potential threat to Texas golden gladecress habitat. Building poultry production houses and associated facilities would cover gladecress habitat in the same manner as would residential or other types of commercial construction. Aerial photography from November 2011 (Google Earth, November 17, 2011) shows 21 poultry farms within the gladecress' range (the approximate zone of the Weches Formation) in Sabine and San Augustine Counties. Of the 21 total, 18 are located on the San Augustine County Weches Formation. None of the existing farms is adjacent to any of the known population locations, and we are unable to determine if any gladecress habitat or plants were lost when these production facilities were built. Among the characteristics in East Texas that make a site desirable for poultry production are long, flat stretches of ground with a good, solid hardpan as opposed to rocky outcrops on slopes, the tops of ridges, or in low-lying areas (Ritter 2012, pers. comm.), such as those occupied by the gladecress. This site-selection preference means that poultry producers would most likely avoid gladecress habitat. In the last 2 years, most of the poultry farm construction has taken place in counties north of San Augustine and Sabine, and the only activity in the Weches Formation zone has been renovations to existing farms (Ritter 2012, pers. comm.). The construction of poultry farms is not considered a threat to Texas golden gladecress because poultry farm site selection does not appear to have significant overlap with gladecress habitat.
Roads
The portion of the CCG Site 1 population that occurred in the SH ROW was impacted when Sunrise Road was widened and straightened in the 1990's (Singhurst 2012g, pers. comm.); however, not all plants were destroyed. A 2011 list of TxDOT planned projects does not show any future road improvements or expansions near known gladecress population sites. Based on the best available information, we conclude that new road construction or improvements to the existing roads does not pose a threat to the gladecress at the three extant sites.
Invasive Species
A major stressor to the habitat of Texas golden gladecress is the ongoing invasion of nonnative and native shrubs and trees into the formerly open-sun, herbaceous, glade vegetation communities. This woody, weedy plant invasion is occurring on at least a portion of all three remaining population sites. Additionally, the historic CCG Site 7 appears, from 2010 aerial photography, to be almost 100 percent overgrown with woody vegetation.
Glades in most parts of the United States are declining due to grazing, fire suppression, and the subsequent invasion by woody vegetation. In presettlement times, glades were maintained by periodic fires and browsing of woody vegetation by white-tailed deer (
Odocoileus virginianus
) and elk (
Cervus canadensis
). This natural disturbance regime changed over the last century due to active fire suppression and diminished numbers of browsers reduced by hunting pressure (Rossiter 1995, p. 2). Although the harsh environment of glades helps to preclude tree establishment, without disturbance such as fire, woody plants will invade (Hartman 2005, p. 4). The exclusion of fire has allowed encroachment of trees, shrubs, vines, and other woody plants into glade communities (Borland 2008, p. 3).
As woody plants mature, they produce canopies that reduce the amount of sunlight reaching the ground. Sun-loving plants like Texas golden gladecress that are adapted to hot, dry sites do not tolerate shade well. Research conducted in Missouri's cedar glades showed that herbaceous plant production rapidly declined when red cedar cover exceeded more than one third of a glade's area (Rossiter 1995, p. 3). A combination of reduced sunlight (shading) and increased leaf litter can act to suppress herbaceous species (Hartman 2005, p. 2). These types of changes in glades that were historically hot and dry can contribute to cooling of the ground and enhancing of moisture content. Wetter, cooler conditions during traditionally hot, dry summer months may be counter-productive for sun-loving glade species by encouraging invasion by cool season vegetation and exotic species. Buildup of a deeper organic layer can also facilitate the establishment of woody plants that results in further shading of the ground (Hartman 2005, p. 2).
Invading species can also compete directly with Texas golden gladecress for water and nutrients. Interspecific competition has been noted as potentially causing reduction in the extent of the root system in several small outcrop plant species, thereby reducing their nutrient uptake (Baskin and Baskin 1988, p. 836). Shading further stresses the herbaceous layer, including the gladecress. In Missouri, stressed glade communities were more prone to invasion from invasive species like
Schedonorus phoenix
(tall fescue),
Sericea lespedeza
(Chinese bushclover), and
Rosa multiflora
(multiflora rose) (Hartman 2005, p. 4). On Texas' Weches Glades, Carr (2005) reported tall fescue at the Chapel Hill site, and Macartney rose was listed as a major invading species in pastures throughout the range of Texas golden gladecress. The Weches outcrops that parallel SH 21 appear to support the heaviest Macartney rose infestation in San Augustine County (Ritter 2011a, pers. comm.). A 1995 report by the Service's Clear Lake Ecological Services' Field Office described known white bladderpod sites, including several with gladecress, all of which needed active management to preclude invasion by woody shrubs (Nemec 1996, p. 1).
Texas golden gladecress habitat has been documented since the 1980's to be affected by an accelerated succession from open herbaceous Weches outcrops to dense shrub thickets and closed canopy woodlands (USFWS 1992, p. 7; Carr 2005, p. 2; Nemec 1996, p. 4). The most serious invaders are included in Table 5. Encroachment of these species is thought to suppress the less competitive components of the community like Texas golden gladecress and white bladderpod (TNC 2003, p. 4). Some of these invasive species can grow on the shallow outcrop soils, while others can invade open space around the edges of the outcrop ledges (USFWS 1992, p. 7). Some of the native invading species are likely controlled by occasional wildfire under natural conditions. More serious are the introduced invaders, including the small hop clover that can cover Weches outcrops and eliminate other vegetation. The introduced shrubs, including Macartney rose and Japanese honeysuckle, will invade open space, including gladecress habitat (USFWS 1992, p. 7).
Table 5—Primary Invasive Species Found in Texas Golden Gladecress Habitat
Scientific name
Common name
Nonnative Species
Rosa bracteata
Macartney rose
Lonicera japonica
Japanese honeysuckle
Stellaria media
chick-weed
Bromus japonicus
Japanese brome
Kummerowia striata
Japanese bush-clover
Ligustrum japonicum
Japanese privet
Meliotus indicus
sour clover
Cynodon dactylon
coastal bermudagrass
Trifolium dubium
small hop clover
Native Species
Andropogon virginicus
broomsedge
Plantago virginica
pale-seeded plantain
Euphorbia
sp.
spurge
Frangula caroliniana
Carolina buckthorn
Rhamnus lanceolata
lanceleaf buckthorn
Crataegus monogyna
hawthorn
Prunus mexicana
Mexican plum
Viburnum prunifolium
blackhaw viburnum
Rhus glabra
smooth sumac
Ulmus alata
winged elm
Berchemia scandens
Alabama supplejack
Cissus incisa
ivy treebine
The three extant Texas golden gladecress sites have shrubs and trees encroaching into formerly open glade habitat. At the Chapel Hill site, Carr (2005, p. 2) noted that 13 scattered pines within a 6,000-square-foot (557-square-meter) area produced a total canopy coverage of less than 10 percent of site, but indicated that future shading effects when the pine trees reach maturity, might prove detrimental. At this same site, other woody plants were controlled, but not eliminated, by regular shredding (Carr 2005, p. 2).
Texas golden gladecress does show some ability to persist at sites that have been overrun by woody vegetation. At the Geneva site, the area with the gladecress was bulldozed, and although the site was reported as destroyed, the species reappeared within several years. At the Chapel Hill site, brush removal actions to benefit white bladderpod also resulted in the reappearance of the gladecress after its apparent absence for 10 years. This suggests that the gladecress' seed bank may be able to remain viable over extended time periods even though the habitat is overgrown by woody species.
Nonnative and native woody species, including woody shrubs, vines, and trees, continue to degrade Texas golden gladecress' habitat across the species' entire range. This threat is significant for the species because it is ubiquitous and has led to declines, or disappearance as in the Chapel Hill site, in the gladecress populations, along with altering its habitat. Based on our review of the scientific information, we conclude that invasion of woody and weedy nonnative and native plants into gladecress habitat is a threat across its range.
Habitat Damage Associated With Grazing
Grazing has been implicated as a habitat threat because it can facilitate the encroachment of undesirable vegetation into the outcrop habitat, and because it may lead to trampling of plants and soil compaction. Historically, the introduction of grazing livestock into East Texas, coupled with heavy grazing pressure, adversely impacted glade sites by facilitating the spread of invasive woody plants, and potentially trampling native plants. Acting in concert with fire suppression, heavy grazing pressure may have accelerated conversion of the grassy prairies and herbaceous glades to the dense, thorny masses of vegetation seen at many sites today (Nemec 1996, p. 4; USFWS 1992, p. 7). Overgrazing of Texas golden gladecress' habitat can promote invasion by woody species and enhance competition on the glade from herbaceous weeds like pale-seeded plantain, Japanese brome, and spurge (USFWS 1992, p. 7). Grazing livestock serve as a source of introduced species' seeds as well as supplying nutrients for competitive native weedy species. Grazing animals can also encourage unpalatable invasive species like Macartney rose to move into areas where more preferred natives have been grazed out (Bridges 1988, p. II-35). The negative impacts to gladecress habitat from woody plant invasion are detailed in the “Invasive Species” section.
There is no documentation of gladecress plants being lost due to trampling. Potential does exist for this to happen, for example, at the Geneva Site, where gladecress plants have been observed growing directly adjacent to and inside the fence where a cow trail is evident. Loss of plants in this small area has not been confirmed and the larger part of this population grows in the SH 21 ROW where no grazing takes place, so it is unlikely that trampling at this site truly constitutes a threat. Grazing also occurs within the fenced private portions of the other two remaining gladecress population sites (CCG Site 1 and Chapel Hill), where individual plants may be subject to trampling if they are growing directly in cattle trails.
Grazing does occur on portions of the three extant population sites, but we do not have information to show that grazing has destroyed Texas golden gladecress habitat or plants. Based on our review of the scientific information, we conclude that the direct effects of grazing are not a threat to Texas golden gladecress.
Land Conversion for Agriculture and Silviculture
Another potential habitat threat is conversion of Weches Glade outcrops to nonnative grass pastures or conversion of existing pasture lands that may contain viable outcrops to pine tree plantations. Over the last 200 years, most of the native vegetation communities of East Texas were dramatically altered by human activities as the region was logged and extensively cultivated (Diggs
et al.
2006, p. 76). Due to widespread land use changes throughout the entire range of the gladecress, and the fact that the glade areas were always somewhat small and surrounded by forest, there is a high likelihood that some glades were negatively affected by past agricultural and silvicultural land cover conversions (USFWS 1992, p. 7). At least one gladecress population was described as being lost to this type of land use change during the 1980's (Turner unpubl. data in TNC 2003, p. 2).
Conversion of native vegetation communities to pasture or row crop in the region is much less common now. The Weches outcrops are not considered desirable substrate for planting to pasture as landowners are not interested in deep plowing, breaking up, or dragging out rocks (Ritter 2011a, pers. comm.). The “Redland” soils that are exposed in the Weches outcrops are thin and rocky. The Natural Resource Conservation Service (NRCS) recommends avoiding these soils because there are not practical conservation practices for these types of sites (Ritter 2011a, pers. comm.). The more prevalent land use change now is from pasture to tree plantation (Ritter 2011a, pers. comm.). Within the last few years, many Sabine and San Augustine County landowners have shifted from grazing to timber planting (Ritter 2011a, pers. comm.). Most timber planting consists of
Pinus taeda
(loblolly pine) and
Pinus palustris
(longleaf pine); planted on 8-10 ft (2.4-3 m) centers. Although landowners will likely avoid planting directly onto Weches outcrops because these rocky soils will not support trees, it is conceivable that the spacing between plantings would allow
trees to be planted near the edges of outcrops (Ritter 2011a, pers. comm., Ritter 2012, pers. comm.). As these trees mature, their canopies may potentially cause shading problems on glade areas (see Invasive Species Section for explanation of negative effects of shading). For example, it appears that former habitat adjacent to the Chapel Hill site may be planted, in part, to rows of trees.
In addition to shading, pine tree plantings may also result in production of large amounts of pine needle litter that could accumulate in small glade openings near the trees. Where a mid-story of trees develops, light may be blocked from reaching the ground level by upper-canopy and mid-story shading; with a subsequent build-up of leaf litter, the herbaceous species can be suppressed. In the face of fire suppression, Missouri glades became choked with litter that kept the ground more moist and cool, leading to replacement of the sun-loving natives by invading cool-season vegetation and exotic species (Hartman (2005, pp. 2-4).
Based on our review of the scientific information, we conclude that planting of pine tree plantations, if in close proximity to occupied glade openings, can constitute a threat to Texas golden gladecress.
Herbicide Use
The candidate assessments for Texas golden gladecress list herbicide use in highway ROWs and for agricultural purposes as a potential threat to the species because of the plant's occurrence within highway ROW's and in pastures. Herbicide use to maintain highway and county road ROW's has the potential to destroy the small subpopulations that exist in the TxDOT ROW's at the Geneva and CCG 1 sites. If timing of the herbicide application coincides with the growing and reproductive period of the year for the gladecress, all individuals that are growing in the ROW might potentially be extirpated if the herbicide contacts all gladecress individuals in these small sites. Herbicide exposure from highway and county road maintenance would affect only a small portion of two extant sites, and recent information suggests that use of herbicides for state and county roads in this area is not a widespread practice (Adams 2011b, pers. comm.; Hunter 2011, pers. comm.). We do not have documentation of negative impacts to the species from herbicide applications for road maintenance. The TxDOT uses herbicides only on an “as needed” basis to eliminate encroaching woody plants or along the edges of the road pavement (Adams 2011b, pers. comm.). San Augustine County does not use herbicides for county roadside maintenance due to costs (Hunter 2011, pers. comm.).
With regard to agricultural herbicide use in San Augustine and Sabine Counties, the NRCS has a program to assist landowners with Macartney rose control using Grazon® P+D herbicide. This program involves a 3-year approach—broadcast spraying from a tractor during the first 2 years, followed by individual plant treatments in the third year. Grazon® P+D has active ingredients of picloram and 2,4-D (dichlor) and can persist in some soils for months and act as a preemergent, killing germinating seedlings. In an appendix to TNC's Conservation Area Plan for the San Augustine Glades (TNC 2003, pp. 30-31), it is one of several herbicides identified as potentially harmful to the gladecress and white bladderpod if used near their habitats. Management recommendations included avoiding use of this herbicide within 200 yards (yd) (183 m) of areas described as habitat within the region, along with limiting timing of use to spot treatments only July 1-August 30. Because Macartney rose is infesting the region of the Weches outcrops, and since this exotic invader is capable of establishing itself in Weches Glades and has been noted as occurring at gladecress population sites, it is reasonable to assume that some areas of glade habitat are included in these treatment programs. So although control of Macartney rose would likely benefit the gladecress in the long term, application of a preemergent herbicide has the potential to eliminate the gladecress altogether if it stays in the soil long enough to kill emerging seedlings. We have no evidence that this type of application has affected Texas golden gladecress populations to date.
Based on our review of the scientific information, we conclude that using preemergent herbicides such as Grazon P+D that persist in the soil for brush control could constitute a threat to Texas golden gladecress emerging seedlings.
Climate Change
Our analyses under the Endangered Species Act include consideration of ongoing and projected changes in climate. The terms “climate” and “climate change” are defined by the Intergovernmental Panel on Climate Change (IPCC). The term “climate” refers to the mean and variability of different types of weather conditions over time, with 30 years being a typical period for such measurements, although shorter or longer periods also may be used (IPCC 2007a, p. 78). The term “climate change” thus refers to a change in the mean or variability of one or more measures of climate (e.g., temperature or precipitation) that persists for an extended period, typically decades or longer, whether the change is due to natural variability, human activity, or both (IPCC 2007a, p. 78).
Scientific measurements spanning several decades demonstrate that changes in climate are occurring, and that the rate of change has been faster since the 1950s. Examples include warming of the global climate system, and substantial increases in precipitation in some regions of the world and decreases in other regions. For these and other examples, see IPCC 2007a, p. 30 and Solomon
et al.
2007, pp. 35-54, 82-85. Results of scientific analyses presented by the IPCC show that most of the observed increase in global average temperature since the mid-20th century cannot be explained by natural variability in climate, and is “very likely” (defined by the IPCC as 90 percent or higher probability) due to the observed increase in greenhouse gas (GHG) concentrations in the atmosphere as a result of human activities, particularly carbon dioxide emissions from use of fossil fuels (IPCC 2007a, pp. 5-6 and figures SPM.3 and SPM.4; Solomon
et al.
2007, pp. 21-35). Further confirmation of the role of GHGs comes from analyses by Huber and Knutti (2011, p. 4), who concluded it is extremely likely that approximately 75 percent of global warming since 1950 has been caused by human activities.
Scientists use a variety of climate models, which include consideration of natural processes and variability, as well as various scenarios of potential levels and timing of GHG emissions, to evaluate the causes of changes already observed and to project future changes in temperature and other climate conditions (e.g., Meehl
et al.
2007, entire; Ganguly
et al.
2009, pp. 11555, 15558; Prinn
et al.
2011, pp. 527, 529). All combinations of models and emissions scenarios yield very similar projections of increases in the most common measure of climate change, average global surface temperature (commonly known as global warming), until about 2030. Although projections of the magnitude and rate of warming differ after about 2030, the overall trajectory of all the projections is one of increased global warming through the end of this century, even for the projections based on scenarios that assume that GHG emissions will stabilize or decline. Thus, there is strong scientific support for projections that
warming will continue through the 21st century, and that the magnitude and rate of change will be influenced substantially by the extent of GHG emissions (IPCC 2007a, pp. 44-45; Meehl
et al.
2007, pp. 760-764 and 797-811; Ganguly
et al.
2009, pp. 15555-15558; Prinn
et al.
2011, pp. 527, 529). (See IPCC 2007b, p. 8, for a summary of other global projections of climate-related changes, such as frequency of heat waves and changes in precipitation. Also see IPCC 2011 (entire) for a summary of observations and projections of extreme climate events.)
Various changes in climate may have direct or indirect effects on species. These effects may be positive, neutral, or negative, and they may change over time, depending on the species and other relevant considerations, such as interactions of climate with other variables (e.g., habitat fragmentation) (IPCC 2007a, pp. 8-14, 18-19). Identifying likely effects often involves aspects of climate change vulnerability analysis. Vulnerability refers to the degree to which a species (or system) is susceptible to, and unable to cope with, adverse effects of climate change, including climate variability and extremes. Vulnerability is a function of the type, magnitude, and rate of climate change and variation to which a species is exposed, its sensitivity, and its adaptive capacity (IPCC 2007a, p. 89; see also Glick
et al.
2011, pp. 19-22). There is no single method for conducting such analyses that applies to all situations (Glick
et al.
2011, p. 3). We use our expert judgment and appropriate analytical approaches to weigh relevant information, including uncertainty, in our consideration of various aspects of climate change.
As is the case with all stressors that we assess, even if we conclude that a species is currently affected or is likely to be affected in a negative way by one or more climate-related impacts, it does not necessarily follow that the species meets the definition of an “endangered species” or a “threatened species” under the Act. If a species is listed as endangered or threatened, knowledge regarding the vulnerability of the species to, and known or anticipated impacts from, climate-associated changes in environmental conditions can be used to help devise appropriate strategies for its recovery.
The climate in Texas has shown a long-term gradual warming trend—pollen, plant macrofossils (fossils large enough to be seen without a microscope), packrat middens (ancient “garbage piles” left by rodents in the genus
Neotoma
), and other evidence show substantial climate changes in Texas over the past 15,000 years (end of the last glacial period) when the mean annual air temperature was 9 °Farenheit (F) (5 °Centigrade (°C)) cooler than present (Diggs
et al.
2006, p. 73). The Texas climate is considered highly variable with seasonal precipitation patterns that dramatically increase from west to east, and temperatures that increase from north to south (Nielsen-Gammon 2008, p.1). Climate models predict increased temperatures, and concurrent increased evapotranspiration, and decreased regular precipitation and soil moisture in Texas (Diggs
et al.
2006, p. 73.), all of which would have negative implications for Texas golden gladecress. Based on a climate model developed by the United Kingdom Hadley Center (HadCM2), temperatures in Texas could increase by 3 °F (1.7 °C) in spring (range of 1-6 °F (0.6-3.3 °C)) and about 4 °F (2.2 °C) in other seasons (with range of 1-9 °F (0.6-5 °C)).
Droughts are not uncommon in Texas (Texas Water Resources Institute 2011, pp. 1-13). The most severe drought recorded in Texas occurred in the 1950's, and in the last 15 years there have been widespread droughts: In 1996, 1999-2000, 2005-2006, 2007, 2010-2011 (Texas Water Resources Institute 2011, pp. 10-12). Projections are for winter precipitation to decrease by 5-30 percent although it may increase by 10 percent in other seasons (Environmental Protection Agency 1997, p. 2).
East Texas is subtropical with a wide range of extremes in weather (Diggs
et al
2006, p. 65). Mean annual temperatures range from 70 °F (21 °C) in the south to approximately 64 °F (18 °C) in the north, although extremes like 0 °F (−18 °C) and 110 °F (43 °C) are observed occasionally. The highest reported eastern Texas temperature was 118 °F (48 °C) in Collin County in 1936 (Bomar 1995 in Diggs
et al.
2006, p. 65). Average rainfall ranges from 60 in (152 cm) at the State's southeastern border to 40 in (98 c) at the western edge. These rainfall differences are related to proximity to the warm, moist air supplied by the Gulf of Mexico. The native vegetation of this region evolved with, and is adapted to, recurrent extremes (Diggs
et al.
2006, p. 67). That said, the Pineywoods region is vulnerable to even small climatic shifts because it is “balanced” on the eastern edge of a dramatic precipitation gradient. Temperature increases that are projected in climate change scenarios will likely be associated with increases in transpiration and more frequent summer droughts. Decreased rainfall may result in an eastward shift in the forest boundary and replacement of the Pineywoods forest with scrubland (Diggs
et al.
2006, p. 80). There is potential for loss of species that are limited to mesic conditions of deep East Texas, such as the hardwood forests surrounding the Weches Glades. There may also be a northerly shift of southerly species based on climate models that predict increasing temperatures and, therefore, increasing evapotranspiration and decreasing regional precipitation and soil moisture (Diggs
et al.
2006, p. 73).
Although East Texas has typically received a greater amount of precipitation during December through March than other regions (Neilsen-Gammon, p. 24), future precipitation trends indicate a decrease in precipitation toward the middle of the 21st century (Nielsen-Gammon, p. 28). The timing of this precipitation is crucial for the Texas golden gladecress, which is dependent on late-fall-through-spring moisture to generate the seeps and pooling that it requires for germination, growth, and reproduction. Reproduction is known to be negatively impacted by drought as evidenced by declines of 91 to 67 plants at the Chapel Hill site and 490 to 96 plants at the CCG Site 1 during the 1999-2000 droughts (USFWS 2010b, p. 5; Singhurst 2011a, pers. comm.). It is unknown how the gladecress will respond to continued years of drought, especially when combined with other threats.
A warmer climate with more frequent droughts, but also extreme precipitation events, may adversely affect Texas golden gladecress by altering the glade habitat the species is known to occupy. It may also improve habitat conditions for invasive plant species and other plants (USFWS 2010b, p. 5). Climate extremes, especially drought and low temperatures, probably play a bigger role in excluding nonadapted species than average conditions will (Diggs
et al.
2006, p. 80). Because the gladecress is a habitat specialist, being closely tied to the geology and soils on the Weches outcrops, it seems unlikely that this species will be flexible in terms of shifting to new habitats if the glades become unsuitable due to lack of winter-spring moisture. Also, if conditions shift in favor of nonnatives, the gladecress will likely be negatively affected. Although the gladecress has survived cycles of drought in the past, as well as some years with extraordinary temperature shifts, it may have done so in a landscape where it was more abundant and with populations distributed in closer proximity to one another. Based on our review, the best
scientific and commercial information did not provide us with information regarding the species' seedbank so we do not know how many consecutive years of poor conditions (in terms of low rainfall and high temperatures) the species can survive.
We lack firm predictions for future patterns of precipitation and temperature that are specific to East Texas. While it appears reasonable to assume that climate change will occur within the range of Texas golden gladecress, at this time we do not have information to indicate specifically how climate change may affect the species or its habitat. However, we do know from recent records that frequent and sustained droughts have resulted in declines, at least in the short term, in the remaining populations.
Other Conservation Efforts
Texas golden gladecress has benefitted to a limited degree from its co-occurrence at some sites with the federally listed white bladderpod. Management activities (brush clearing) carried out in 1995 at the Chapel Hill site for the white bladderpod resulted in a return of the gladecress after a 10-year absence (Nemec 1996, p. 5). However, nonnative shrubs quickly reinvaded the site, and repeated maintenance was needed. The landowner at this site has continued to mow at least once per year, keeping the habitat relatively open (Singhurst 2012f, pers. comm.), and the gladecress and bladderpod continue to occupy this site. A Partners for Fish and Wildlife Program project involving restoration of habitat (brush clearing) and planting of white bladderpod was planned to benefit both species although the gladecress has not been detected at the site to date.
The Service funded several projects with TNC, including one that provided for 3 years of status surveys for gladecress and bladderpod. These were completed in 2006 and were the sole source of population numbers for these species for several years. The TNC also identified a total of 44 potential sites for both plant species using GIS data (aerial, geology, and hydrology sources) and obtained permission to visit 14 of them, but found little Weches habitat and no new gladecress populations (Turner 2003, p. 4).
In the early 2000's, the Service collaborated with Mercer Arboretum and other partners, including TNC and the Pineywoods Native Plant Center at Stephen F. Austin State University in Nacogdoches, Texas, to collect gladecress seeds for cultivation, research, and long-term storage, and as seed sources for reintroduction work. Seeds were kept by Mercer Arboretum for long-term storage as well as germination and cultivation work. Nothing has been done recently with gladecress research or reintroduction efforts. The species was successfully introduced into apparently appropriate habitat in Nacogdoches County at a site located approximately 30 mi (48 km) west of its historic range in the late 1980's, where it grew and reproduced through 2011 when it was eradicated by construction of a pipeline. The success of this reintroduction project may bode well for future efforts to increase the numbers of populations by reintroductions or introductions to new sites.
Summary of Factor A
The highest levels of threat to Texas golden gladecress are the loss and degradation of habitat. Specifically, surface quarrying of glauconite and the exploration and development of oil and natural gas wells and associated roads and pipelines have destroyed 50 percent of the known populations between the mid 1990's and 2011. These threats are likely to continue since glauconite is currently in demand for road bed, well pad construction, and for fertilizer, and development of the natural gas-bearing Haynesville Shale, which underlies the entire range of Texas golden gladecress, has been very rapid during the last several years. Portions of two extant populations extend into SH ROW's where TxDOT has the ability to provide some protections. Nevertheless, much of the species' potential habitat throughout the range occurs on private lands that, due to lack of access, have not been surveyed; therefore, the current level of threats across these lands cannot be assessed. Surface quarrying of glauconite and oil and gas development pose significant threats to the known extant populations and associated habitats of the gladecress.
Texas golden gladecress also faces threats throughout its range from competition for light and nutrients from both native and nonnative invasive woody plants, including the nonnative Macartney rose. We have determined that the extant populations will decline or become extirpated unless they are periodically maintained to remove invading trees and shrubs. Additionally, herbicides used to control Macartney rose may be a threat to the gladecress if applied or persisting in the soil during the species' period of growth, from fall through early summer.
A recent, ongoing trend in local land use is the conversion of open pasture to pine plantations. We found no evidence that grazing and trampling by livestock may be a threat to the species, and we believe that pastures provide suitable habitat for the sun-loving gladecress. However, densely planted pine trees may degrade the species' habitat due to competition for light and nutrients, and by contributing masses of leaf litter onto formerly sparsely vegetated glades.
Finally, the information regarding climate change is not yet specific enough for us to determine the potential long-term effects to the gladecress habitat. However, long-term drought has negatively affected and will likely continue to negatively affect the reproduction and germination of gladecress seeds. Therefore, we conclude that Texas golden gladecress faces significant threats from habitat loss, destruction, modification, or curtailment of the species' habitat or range.
B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes
Limited collection of gladecress has occurred for scientific purposes; only voucher specimens and several seed collection events are documented. Dr. Elray Nixon collected seed in 1987 and successfully created a new population when he introduced the seed onto an outcrop in Nacogdoches County. The Mercer Arboretum, a participating institution in the Center for Plant Conservation, collected seed in 2001—maintaining some in long-term storage and planting some in germination trials. There are no records of any collections of seeds or other plant materials in the last few years. Because these collections were limited, we do not believe that this activity constituted a threat to the species. There is no information to suggest that Texas golden gladecress is collected for commercial, recreational, or educational purposes, and we have no reason to believe that this factor will become a threat to the species in the future. Therefore, based on our review of the best available scientific and commercial information, we conclude that collection or overutilization of Texas golden gladecress is not a threat to the species.
C. Disease or Predation
There is no available information regarding disease in Texas golden gladecress. There is no information regarding predation by wildlife on the species. Grazing is ongoing across the range of the gladecress and occurs on portions of all extant population sites; however, there is no information to document that cattle eat gladecress. No studies have been conducted to investigate the effect of grazing or
herbivory specifically on Texas golden gladecress. George (1987, p. 17) studied the herbaceous flora of three Weches outcrops in San Augustine County and saw little grazing within his study plots although cattle were present at all three sites. Therefore, based on our review of the best available scientific and commercial information, we conclude that disease and predation on Texas golden gladecress, including predation associated with grazing, are not threats to the species.
D. The Inadequacy of Existing Regulatory Mechanisms
Under this factor, we examine whether existing regulatory mechanisms are inadequate to address the threats to the species discussed under the other factors. Section 4(b)(1)(A) of the Act requires the Service to take into account “those efforts, if any, being made by any State or foreign nation, or any political subdivision of a State or foreign nation, to protect such species * * * .” In relation to Factor D under the Act, we interpret this language to require the Service to consider relevant Federal, State, and tribal laws, regulations, and other such mechanisms that may minimize any of the threats we describe in threat analyses under the other four factors, or otherwise enhance conservation of the species. We give strongest weight to statutes and their implementing regulations and to management direction that stems from those laws and regulations. An example would be State governmental actions enforced under a State statute or constitution, or Federal action under statute.
Having evaluated the significance of the threat as mitigated by any such conservation efforts, we analyze under Factor D the extent to which existing regulatory mechanisms are inadequate to address the specific threats to the species. Regulatory mechanisms, if they exist, may reduce or eliminate the impacts from one or more identified threats. In this section, we review existing State and Federal regulatory mechanisms to determine whether they effectively reduce or remove threats to the Texas golden gladecress.
The greatest threats to the gladecress include loss of habitat and the plants themselves due to actions that remove the substrate under the populations or that cover them up. These types of actions have been associated with quarrying of glauconite; construction related to natural gas and oil exploration and production; conversion of native glades or pastures with glades and outcrops to other land uses, most recently planting to pine plantations; and potentially herbicide applications for purposes of controlling the invasive Macartney rose. State and Federal regulations that might help conserve rare species on State highway ROWs, including avoidance or minimization of habitat destruction, as well as regulations that would protect plants from herbicide applications, are requirements only for already listed species; therefore, these regulations do not apply to gladecress. Likewise, no existing regulations protect the species on privately owned land, where most of the remnant gladecress is found.
Currently, Texas golden gladecress is not protected by State or Federal laws. All of the populations occur on private property, and portions of those populations extend onto SH ROWs. As such, there are no regulatory mechanisms in place to address the threats to the species.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
Small Population Size
The Texas golden gladecress remains in only three small populations. Small populations can be prone to extirpation, especially if a series of drought years greatly reduces seed production and depletes the soil seed bank. The Service (1992, p. 8) noted that for a species like the white bladderpod, with only small populations and wide natural annual fluctuations in plant numbers, as well as fragmented habitat across its range, recolonization after a population loss would require long-distance seed dispersal. Although we have no information regarding the gladecress' seed dispersal patterns or distances, we do know that the gladecress' habitat is exceedingly fragmented, with fewer and smaller known populations than the bladderpod, and further distances between populations. This makes the prospects for recolonization after a potential loss of a gladecress population very remote.
Small populations can also be prone to extirpation from a single adverse natural or manmade event. The population at the Chapel Hill site is a good example of this vulnerability. Carr (2005, p. 2) reported that Texas golden gladecress habitat was extremely limited at Chapel Hill and that the numbers of gladecress plants would also always be restricted by the small size of the available habitat. He concluded that the population was so small that a single adverse event could extirpate the species from this location. The small population size and the small number of extant populations of gladecress increases each population's vulnerability to the significant threats listed in Factor A. Low numbers of plants, confined to very small areas, can be totally eradicated by actions such as installation of pipelines, excavation of mines, or construction of well pads, roads, or other types of construction. The remaining gladecress occurrences are so small that they can fall completely within the footprint of one well pad, or even within the width of a pipeline excavation. Small population size also increases the risk of total loss of populations due to contact with herbicides or shading and leaf litter accumulation from pine tree plantings because these threats are likely to affect the entirety of any given occurrence. Sustained drought may reduce the reproductive effort of a population, and this can lead to an overall decrease in fitness for the remaining populations. Reduced reproductive effort affects the seed bank, which represents the reproductive capacity of each gladecress population. The combined effects of drought, impacts from oil and gas development, herbicide treatment, shading, and competition place the remaining three populations at a high extinction risk, exacerbated by their small population size and narrow distribution.
In addition to increasing vulnerability to direct threats such as pipeline construction, small population size can result in a decrease in genetic diversity due to genetic drift (the random change in genetic variation in each generation) and inbreeding (mating of related individuals) (Antonovics 1976, p. 238; Ellstram and Elam 1993, pp. 218-219). Genetic drift can decrease genetic variation within a population by favoring certain characteristics and, thereby, increasing differences between populations (Ellstram and Elam 1993, pp. 218-219). This increased difference between populations can diminish a species' ability to adapt to the selective pressures of a changing environment (Newman and Pilson 1997, p. 360; Ellstrand 1992, p. 77). Self-fertilization and low dispersal rates can cause low genetic diversity due to inbreeding (Antonovics 1976, p. 238; Barrett and Kohn 1991, p. 21).
Although we do know that Texas golden gladecress exists in small populations in a fragmented landscape, no information is available regarding the genetic diversity exhibited by the species.
Summary of Factor E
Texas golden gladecress is a historically rare species with some adaptations, such as a mixed mating system, that help to alleviate part of the
inherent risks of small population size. The continued existence of Texas golden gladecress is negatively impacted by natural factors including being limited to only a few remaining populations that contain very small numbers of individual plants with a distribution restricted to extremely small areas of outcrop. The species' current, reduced occurrences across a range that has been highly fragmented by past and ongoing human activities increases its vulnerability. With only three remaining populations, loss of an entire population could be catastrophic for this species' long-term viability. Therefore, based on our review of the best available scientific and commercial information, we conclude that the small number of remaining populations, all of which are small in size, in conjunction with the threats described in Factor A, constitutes a threat to the species.
Proposed Determination
We have carefully assessed the best scientific and commercial available information regarding the past, present, and future threats to Texas golden gladecress and have determined that the species warrants listing as an endangered species throughout its range. Significant factors that support this determination include the following: (1) Loss of five of eight known populations and their associated habitat (Factor A); (2) the ongoing threat of loss or severe degradation of habitat on portions of the three remaining population sites from glauconite quarrying activities, oil and gas development, pipelines, wells, and brush encroachment (Factor A); (3) the threat of loss of emerging seedlings from herbicides used to control brush across the entire range of the species (Factor A); and (4) the impact of extreme or successive years of drought (Factor A). These factors place this species at high risk of extinction. Limited distribution and small population size of these remnant populations (Factor E) significantly heightens the danger of extinction due to threats from Factor A. The threats are ongoing and occur throughout the range of the species. Therefore, we find that a proposed determination as an endangered species, rather than a threatened species, is appropriate.
The Act defines an endangered species as “any species which is in danger of extinction throughout all or a significant portion of its range.” A major part of the analysis of “significant portion of the range” requires considering whether the threats to the species are geographically concentrated in any way. If the threats are essentially uniform throughout the species' range, then no portion is likely to warrant further consideration. Based on the threats to Texas golden gladecress throughout its entire known range (northern San Augustine County, into the northwest quarter of Sabine County, in a roughly 3-mi (5-km) wide band paralleling SH 21), we find that the species is currently in danger of extinction throughout all of its range, based on the severity and scope of the threats described above. The species is proposed as an endangered species, rather than a threatened species, because the threats are occurring now or will in the near term, and their potential impacts to the species would be severe given the limited known distribution of the species, the small population sizes at all three sites, and the tiny area occupied by these small populations, putting this species at risk of extinction at the present time. Since these threats extend throughout its entire range, it is unnecessary to determine if it is in danger of extinction throughout a significant portion of its range. Therefore, on the basis of the best available scientific and commercial information, we propose listing the Texas golden gladecress as an endangered species throughout its range in accordance with sections 3(6) and 4(a)(1) of the Act.
Neches River Rose-mallow
A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range
The principal threats affecting the habitat of the rose-mallow include habitat loss and modification through the encroachment of nonnative and native plant species, hydrological changes, and construction and development projects. These threats may be intensified by the restriction of the species' known range to the Neches River basin and the Mud and Tantabogue Creeks of five counties within East Texas. Other stressors, including silviculture, herbicide use, trampling, natural gas activities, and climate change effects were reviewed for their impacts to the rose-mallow.
Nonnative Plants
Nonnative plant species are a constant threat to native flora throughout the Gulf coast prairies of Texas and Louisiana (McCormick 2005, p. 23). We consider the potential threat from two nonnative species, chinese tallow and coastal bermudagrass, that occur in rose-mallow habitat (Miller 2011, pers. comm.). Chinese tallow was introduced to the United States in the 1700's from China (McCormick 2005, pp. 7, 8). This species reproduces quickly, reaches reproductive maturity in as little as 3 years, and can remain reproductive for at least 60 years (United States Geological Survey (USGS), 2000, p. 2), producing an abundance of seed annually (Potts 1946, p. 375; Conway
et al.
2000, pp. 268-269). Chinese tallow tolerates a range of habitat conditions including full sunlight and shade, flooding, and drought (USGS 2000, p. 1). The rose-mallow occurs in perennially and intermittently wet habitats. Butterfield
et al.
(2004, p. 338) found that chinese tallow grew faster than native species, such as loblolly pine, water tupelo (
Nyssa aquatic
), blackgum (
N. sylvatica
), and sweetgum in both perennially and intermittently wet habitats. Chinese tallow occurs at all rose-mallow sites (Miller 2011, pers. comm.) at varying densities, limiting the growth and reproduction of the rose-mallow through competition for light, space, and nutrients.
Burning, mechanical, and chemical (herbicide) means can be used to control chinese tallow. However, prescribed fire has produced complex and highly variable results in chinese tallow and may not be an effective management tool (Grace 1998, entire; Grace 2011, pers. comm.). The Davy Crockett NF is establishing a regular burn cycle of 3-4 years for all compartments containing the rose-mallow to control chinese tallow and to mimic the historical fire regimes of the Coastal Plain (Landers
et al.
1990, p. 136). The Davy Crockett NF Resource and Land Management Plan (specific to the streamside Management Area 4) allows for mechanical means and prescribed fire to maintain the native plant community but prohibits the use of chemical agents (herbicides) unless applied by hand or through nonaqueous form within 100 ft (30.5 m) of the rose-mallow (USDA 1996, p. 154). Current mowing activities along ROWs may abate some growth of chinese tallow, but management actions on these sites should also be evaluated. Chemical methods are not being used to control chinese tallow.
Coastal bermudagrass is an introduced bermudagrass cultivar that has been widely planted in the southern United States for livestock forage. It is adapted to a wide range of soil types and climates and tolerates both drought and periodic inundation (Burton and Hanna 1985, p. 247). In dry climates, this cultivar will thrive along irrigation ditches and streambeds, agricultural fields, and roadside areas (Burton and Hanna 1985, p. 247). Due to its hybrid origin, coastal bermudagrass produces very few viable seeds and is established
by planting sprigs (rhizomes and stolons) (Stichler and Bade 2012, p. 1). Once established, coastal bermudagrass tends to produce dense monocultures where native species cannot persist. However, coastal bermudagrass has only been seen on one extant site of the rose-mallow. This is a secluded portion of the privately owned land of Boggy Slough, where coastal bermudagrass appeared to be planted (Allen 2011a, pers. comm.) and had not spread to any other sites on the property or the adjacent SH 94 ROW population. Since coastal bermudagrass is not present at most rose-mallow populations, and has a low rate of spread, we believe it is not a significant threat. However, coastal bermudagrass could become a threat if introduced into rose-mallow habitats.
In summary, all populations of the rose-mallow are negatively affected by chinese tallow, a nonnative tree species that competes with the rose-mallow for available soil nutrients, space, and light. Coastal bermudagrass is not a current threat to the rose-mallow.
Native Species
Sweetgum and green ash (
Fraxinus pennsylvanica
) are native, deciduous trees of East Texas found at all rose-mallow sites (Miller 2011, pers. comm.). Sweetgum is found on a variety of soils but grows best on moist, alluvial clay and sandy loams of river bottoms (Kormanik 2004, p. 790, in Burns and Honkala 1990). Green ash also tolerates a range of soils and in Texas is abundant in clay or silty loams of floodplains (Johnson 1980, in Gucker 2005, p. 15). Both species also grow in full sun to partially shaded habitats. Therefore, both the sweetgum and green ash are well adapted to the hydric alluvial soils and open canopies that the rose-mallow needs. In the absence of other competing species, sweetgum and green ash can attain large sizes (50-100 ft (15-30 m)) (Dickerson 2002, p. 1) and can reduce the open canopy needed by the rose-mallow (Kirkman 1995, pp. 12, 15). Although naturally occurring wildfires or prescribed fire limit the abundance of these tree species, prescribed fire is not a widely accepted method of ROW maintenance. Four rose-mallow populations that were monitored in 2011 were overgrown with sweetgum and green ash (Miller 2011, pers. comm.; TXNDD 2012a, pp. 1-11, 20-28). Two of these sites were on ROWs, and prescribed burning had not been used at the other two sites. Consequently, about 27 percent of the rose-mallow's populations are impacted by competition and shading from native sweetgum and green ash trees. Therefore, native species that compete with rose-mallow for light and nutrients are a moderate threat to the species, and may become a significant threat if maintenance is not continued at occupied sites.
Hydrological Changes
The rose-mallow can be found in both intermittent and perennial wetlands along oxbows, sloughs, terraces, ponds, and other low-lying areas in habitats with minimal standing water. Wetlands are ecological communities with hydric (flooded or saturated) soils. Many aquatic species, including the rose-mallow, are adapted to highly variable rates of water flow, including seasonal high and low flows and occasional floods and droughts. For example, the rose-mallow may require high precipitation and flowing water or floods to disperse seed (Warnock 1995, p. 20; Scott 1997, p. 8; Reeves 2008, p. 3).
Channelization, drainage, dredging, ditching, stream diversion, impoundments, ground water withdrawals, and levees have historically caused wetland loss (North Carolina State University Water Quality Group 2012,
http://www.water.ncsu.edu/watershedss/info/wetlands/wetloss.html
). Some degree of hydrological change is seen at all of the rose-mallow sites. At Boggy Slough, shifts of river and creek beds have left meandering scars and remnant oxbows. Several levees have been built that have changed the natural landscape and flow patterns at this site to make ponds available for duck hunting, thereby converting seasonally inundated wetlands to permanently flooded wetlands (Miller 2011, pers. comm.). On TLC land, rose-mallow plants once lined the perimeter of a flatwoods pond. After 2003, a stock pond was built there (TXNDD 2012a, p. 18) in what was likely part of an overflow channel from Tantabogue Creek. The constructed stock pond altered the natural surface hydrology by retaining overflow from Tantabogue Creek, preventing it from draining south to the rose-mallow site. During the 2011 survey conducted by the Service and TPWD, we observed only 539 rose-mallow stems, most of which were in relatively poor condition. The hydrologic alteration of the site combined with drought conditions reduced the height of rose-mallow stems, thus increasing their vulnerability to browsing by cattle. During 2011, drought also led to increased grazing pressure in rose-mallow habitats. Once normal rainfall has resumed and preferred forage sources become available, grazing pressure is expected to diminish.
All four of the Davy Crockett NF sites may also be affected by hydrological changes. A pine-oak forest on adjacent private land regulates the amount, timing, and possibly the rate of water flow westward into compartment 55. Removal or alteration of the pine-oak forest could change the hydrology of compartment 55, thereby also changing the rose-mallow seed dispersal range; however, the likelihood of these tree removal or habitat alteration activities are unknown but likely minimal. All NF sites censused in 2011 were completely dry except for compartment 20, where a small pond to the south drains into the compartment (Miller 2011, pers. comm.). We found no records of hydrologic alterations in compartments 20 and 11. In 2000, when the rose-mallow was introduced into a wetland on compartment 16, a beaver dam was present. When the dam broke in 2002, water infiltrated the site and the original hydrology was altered (TXNDD 2012a, p. 44). Water depth at the site was likely altered, but rose-mallow plants were still observed as recently as 2011. Additional beaver activity, such as selective cutting and damage to certain tree species, was evident only at Boggy Slough. These activities along with dam building by beavers were not evident and are not considered a threat to the rose-mallow. Although beaver dams could impact the site's hydrology and vegetation, beavers are not currently a threat nor are anticipated to become a threat to the rose-mallow.
Some of the rose-mallow populations occur on private lands where modification of a Federal jurisdictional wetland could require a Clean Water Act permit. However, not all actions affecting wetlands require Federal agency review. These privately owned sites may be affected by wetland and hydrological changes through anthropogenic and natural causes and could cause a loss of a few individuals or a population. Therefore, hydrological changes are a threat to the rose-mallow and its habitat.
Development and Construction Projects
In 1978, the Angelina and Neches River Authority (ANRA) proposed the construction of a reservoir known as Lake Columbia (previously known as Eastex), in Cherokee and Smith Counties, Texas (ANRA 2012,
http://www.anra.org/divisions/reservoirs/columbia/history.html
), to supply water for five surrounding counties (U.S. Army Corps of Engineers (USACE), 2010, pp. 2-4, 3-43). The dam for this reservoir would be constructed on Mud Creek and would impound approximately 195,500 acre-feet (ac-ft)
(241 million cubic meters, mcm) of water in a reservoir reaching 14 mi (22.5 km) upstream (USACE 2010, p. 1-1). Up to 85,507 ac-ft (1105 mcm) of water would be diverted from the downstream flow of Mud Creek (USACE 2010, p. 1-1). An extant rose-mallow population is found at the intersection of Hwy 204 and Mud Creek but is not within the permitted project area reviewed in the draft Environmental Impact Statement. A Habitat Evaluation Procedures analysis of the permitted project area did not document any rose-mallow plants (Walker 2011, pers. comm.). We are also unaware of any rose-mallows inside the proposed project area. The Hwy 204 ROW site is a perennial wetland where plants remain inundated year round; therefore, a change in the water levels at this site could make it unsuitable for rose-mallow or could restrict seed dispersal downstream. Drought conditions could also exacerbate these impacts, and the reduced downstream water flows could completely extirpate the Hwy 204 site (USACE 2010, p. 4-154; Heger 2012, pers. comm.).
Only the Hwy 204 rose-mallow population of Mud Creek will be impacted from this project, constituting nine percent of the total extant population. Consequently, we consider development and construction projects to be a minor threat to the rose-mallow.
Upgrades and Construction for ROWs, Roads, Bridges, and Other Structures
Three rose-mallow populations are located on or near SH ROWs in Houston, Trinity, and Cherokee Counties. These ROW populations are vulnerable to impacts from bridge and road expansion and upgrades, including hydrologic changes, soil movement, and altered wetland or riparian vegetation. For example, in 2005, a proposed bridge replacement on SH 230 would have altered approximately 4.91 ac (2 ha) of rose-mallow habitat south of the ROW and 0.07 ac (0.03 ha) north of the ROW (Adams 2005, p. 1). To mitigate for these impacts, TxDOT proposed to acquire an additional 5 ac (2.02 ha) of rose-mallow habitat located north of the TLC property; unfortunately, the proposed mitigation plans fell through (Adams 2011a, pers. comm.). Bridge replacement is continuing along SH 94, but as of 2011 had not progressed into rose-mallow habitats (Adams 2011c, pers. comm.). Although the human population has increased in Houston, Trinity, and Cherokee Counties in East Texas (U.S. Census Bureau 2012)), no large road expansion projects are anticipated for the two additional ROW sites (Adams 2011c, pers. comm.). Although road projects are mainly restricted to ROW easements, they may potentially impact three populations representing 27 percent of the total known population. Therefore, SH ROW maintenance and bridge and other structural projects will continue to be a threat to the species.
Silviculture
Pine plantations in East Texas are established mainly on uplands that are managed to mimic old fields or grassy savannas (Fox
et al.
2007, p. 340). Site preparation may include anchor chaining, chopping, burning, root raking, shearing, and disking (Balmer and Little 1978, p. 60). One rose-mallow population on private property south of Hwy 230 was extirpated when the site was converted to a pine plantation sometime after 2003 (Poole 2011b, pers. comm.; TXNDD 2012a, pp. 61-67). Three additional sites in or near rose-mallow populations have evidence of clearing, including: adjacent land south of the Davy Crockett NF compartment 55; an extirpated site located south of the extant Lovelady site, Houston County; and the privately owned site at Champion, Trinity County. Rose-mallow populations may also be potentially impacted by herbicides applied to pine plantations that drift into the rose-mallow habitat (see discussion below). Herbicide treatments are increasingly popular because they remove unwanted plant growth without causing soil erosion from the site; however, herbicide use increases incidents of water pollution and aerial drift to nontarget sites (Balmer and Little 1978, p. 63). Herbicide damage was evident along the Hwy 230 ROW, south of the extant rose-mallow site on TLC property, but whether this damage was the result of herbicide use by the landowner at the pine plantation is unknown. The perennial or intermittent wetlands that the rose-mallow inhabits are usually not suitable habitats for pine plantations. Therefore, we conclude that silviculture currently is not a threat to the rose-mallow.
Herbicide Use
Several incidents have been documented of herbicide impacts to rose-mallow plants on ROWs and on privately owned lands. A subpopulation with approximately 50 plants, on private property in Trinity County south of Hwy 230, was extirpated by herbicide use (USFWS 2010a, p. 7). Herbicide drift along the SH 230 ROW (Gordon 2009, pp. 3-4) caused the rose-mallow population to decline from 14 plants in 1999 (Poole 2001, p. 2) to zero plants in 2002 (Miller 2011, pers. comm.). The Land and Resource Management Plan of Davy Crockett NF restricts the use of nonaquatic herbicides unless hand-applied (USDA 1996, p. 153); there have been no documented herbicide impacts to rose-mallow in any of its four compartments. The TxDOT uses herbicides to remove woody vegetation from ROWs (Miller 2005, pers. comm., in USFWS 2006, p. 7; Adams 2011c, pers. comm.), but mechanical clearing methods have largely replaced the use of herbicides in these ROW areas. Although herbicides can be an effective management tool for the control of some nonnative species, dispersal downstream and unexpected rainfall could impact individual plants or whole populations, depending on the nature of the herbicide. Therefore, we conclude that herbicides are a threat that could impact 7 of 11 (64 percent) total rose-mallow populations.
Trampling by Feral Hog and Cattle
Feral hogs (
Sus scrofa
) were first introduced to the mainland of North America (Wood and Barrett 1979, pp. 237, 238) in Texas in 1542, although large-scale introductions did not occur until the 1930's (Isle and Hellgren 1995, p. 793). Feral hogs are omnivores that dig up the soil in search of roots, tubers, and invertebrates. Feral hogs use their snouts to turn over soil, creating mounds and depressions (Arrington
et al.
1999, p. 535). Hogs transition from foraging in oak stands during winter months, moving in summer to swamp and marsh edges to feed on grasses, sedges, tubers, and roots (Wood and Roark 1980, pp. 507-509). Feral hogs are able to travel long distances to feed, and often uproot vast areas of habitat. Feral hogs reach sexual maturity at 6-8 months (Wood and Barrett 1979, p. 242) and have large litter sizes. Hogs can inadvertently incur severe damage to other food resources and habitat during their regular foraging activity. Feral hog damage has historically been recorded at Mill Creek Gardens, but uprooting of rose-mallow taproots was not observed (Creech 2011a, pers. comm.; Miller 2011, pers. comm.). Feral hog tracks were observed on all four NF sites; however, plants were not damaged by herbivory or trampling (Miller 2011, pers. comm.). Feral hogs generally do not affect rose-mallow populations because the habitat is permanently or temporarily flooded, limiting their access. However, drought may enhance accessibility to rose-mallow sites, thus increasing their susceptibility to trampling. Growth of the feral hog populations could also lead to increased soil disturbance and impacts to the native vegetative community, which
could create prime conditions for nonnative species to invade. Feral hog tracks have been limited to a few rose-mallow sites with minimal damage to habitat. However, no direct impacts to rose-mallow plants have been observed. Therefore, we determine that feral hogs are not a stressor to the species.
It is estimated that livestock grazing has damaged 80 percent of stream and riparian ecosystems in the southern United States (Belsky
et al.
1999, p. 419). The damage includes increased sedimentation, decreased water quality, and trampling and overgrazed stream banks where succulent (high water content) forage exists (Armour
et al.
1994, p. 10; Fleischner 1994, p. 631; Belsky
et al.
1999, p. 419). Trampling causes soil compaction and damage to both above- and below-ground vegetative plant structures and increases soil erosion (Warren
et al.
1986, p. 491). Livestock owned by a neighboring landowner were present on TLC's property at Lovelady. TLC has attempted to exclude these livestock, and has proposed constructing an exclusion fence around the current location of the rose-mallow population; however, funding has not been secured (Dietz 2011, pers. comm.). The rose-mallow at Lovelady is concentrated along a low area leading into a stock pond (Miller 2011, pers. comm.). We have not observed damage to rose-mallow from cattle trampling at Lovelady (Miller 2011, pers. comm.), and are not aware of other rose-mallow sites being trampled by livestock. In summary, cattle are present at only one rose-mallow site (9 percent of the total known population), and the effects are small and may be remedied through exclusion devices. Therefore, we conclude that livestock grazing is not a threat to the rose-mallow.
Natural Gas Pipelines and Well Activity
The Haynesville/Bossier and Eagle Ford Shale formations in East Texas are currently being developed for oil and natural gas production. In Harrison County, Texas, there is a single record of rose-mallow at a privately owned site that has not been seen since 1980 (Birnbaum 2011, pers. comm.; TXNDD 2012a, pp. 12-13); we do not know if the site has been affected by ongoing natural gas exploration in that county. The RRC regulates the oil and natural gas industry in the state of Texas and maintains a database with proposed activities. Several of the counties with known populations of rose-mallow, including Houston, Trinity, Nacogdoches, and Cherokee Counties, may be subject to increased oil and natural gas exploration in the future (RRC 2012). However, oil and gas exploration was not observed on or directly adjacent to any of the rose-mallow populations that the Service observed in 2011, and currently there are no proposals near extant rose-mallow populations. Therefore, we determine that oil and natural gas exploration activities are not currently a threat to the rose-mallow.
Climate Change
We discuss the topic of climate change in greater detail in the Factor A Threats Analysis for the Texas golden gladecress, which is also found in East Texas. In summary, the consensus of climate models predicts that the climate in East Texas will become warmer and will experience both more frequent droughts and more extreme precipitation events. Diggs
et al.
(2006, p. 80) states that climate extremes, particularly drought and low temperatures, have greater influence than average conditions do on excluding nonadapted species. Extreme precipitation events (such as tropical storms) may adversely affect the rose-mallow by altering flow regimes and by temporarily increasing the depth of its aquatic habitat to a level it cannot survive. A warmer climate with more precipitation extremes may also increase competition from native and nonnative invasive plant species (USFWS 2010a, p. 8). The timing of precipitation is also crucial for the rose-mallow, since seed dispersal is dependent on flowing water.
In October 2011, all rose-mallow populations and habitats showed evidence of damage from the previous 3 years of drought, including changes in leaf morphology, increased herbivory by livestock, dead plants at specific sites, and lower water levels in perennial wetlands. The survival of rose-mallow populations during previous drought cycles may have been aided by its greater abundance and by greater habitat contiguity; habitat fragmentation and isolation impede the recolonization of sites, following a catastrophic loss, from neighboring seed sources. Plant populations may also recover from the soil seed bank (viable seeds that remain dormant in the soil until conditions become favorable). We do not have information on the abundance or distribution of the rose-mallow seed bank or how long its seeds may remain in a dormant yet viable condition.
Nevertheless, climate change models have less precision at the fine geographic scale of the rose-mallow's range, and we lack specific information on the species' ability to withstand extreme conditions. We conclude that the effects of climate change may be a threat to the rose-mallow in the future, but are not currently a threat to its survival. However, drought conditions, which may worsen with changing climates in the region, may have significant effects on the rose-mallow populations, especially in combination with other threats discussed in this section.
Other Conservation Efforts
Three populations of the rose-mallow exist along SH ROWs in Houston, Trinity, and Cherokee Counties. TxDOT and TPWD currently operate under a revised 1988 Memorandum of Understanding (MOU) that governs management actions targeting conservation of listed species and key habitats on SH ROWs that may potentially affect natural resources within facilities owned or managed by TPWD. Since the rose-mallow is not a listed species, the MOU relates to protection of rose-mallow habitat if the proposed projects include the following: Contains 1.0 ac (0.54 ha) of new ROW within floodplains or creek drainages; requires channel modifications to streams, rivers, or water bodies; and requires realignment of channels with mature woody vegetation; or projects that may impact mature woody or native vegetation (Texas Administrative Code 1999, p. 4). Although a formal mechanism via the MOU has been established to review projects and alleviate or eliminate threats to Federal and State-listed species and key resources, there have not been any projects that fit these standards that have been recently reviewed under the MOU.
The five remaining populations, including a portion of the Hwy 94 site, are located on private lands. Historically, two Candidate Conservation Agreements (CCAs) were formed between the Service and Champion International (Champion) in 1998 and with Temple-Inland Forest Products (Temple-Inland) in 2002 to conserve the rose-mallow on both sites. CCA's are not legally binding and private landowners are not restricted by guidelines outlined in the CCA. Champion's 5-year CCA, included 40 ac (16.2 ha) of wetland and was located east of White Rock Creek in Trinity County (Champion site in Table 4). Management guidelines included: Maintain 100-ft (30-m) buffer around occupied and dispersal habitat, free from timber harvesting, site preparation, and reforestation activities; minimize hydrological alterations; inhibit filling or pilling debris or material on populations; and apply herbicides only
by hand and at times of little or no wind (USFWS 1998, p. 4). The Champion property was sold to Temple-Inland in 2001 and in 2004, the CCA expired (USFWS 2010a, p. 9). The Temple-Inland CCA covered an area that has a 20-ac (8.1-ha) wetland with rose-mallow (Boggy slough site in Table 4); the plants declined due to drought and alteration of an onsite wetland. A smaller wetland with rose-mallow plants was drained in order to regulate water levels of the larger wetland, which was to be used by Temple-Inland for recreational hunting (USFWS 2002, p. 3; USFWS 2010a, p. 9). The Temple-Inland CCA was valid 2002-2004. Contact was made with the owners and the Service and TPWD visited the site in October 2011 where plants appeared healthy, but nonnative and native species encroachment into rose-mallow habitat was observed (Miller 2011, pers. comm.).
Lovelady was once owned by the Natural Area Preservation Association and is now owned by TLC. Thirty acres (12 ha) of land were purchased in 2004, located north of Hwy 230 (TLC 2011,
http://www.texaslandconservancy.org
). Purchase of this easement on private land was specifically for the conservation of the rose-mallow; however plants occur on private land, and they are not offered protection under the Act unless a Federal action or funding is planned. However, TLC has initiated a voluntary effort to construct a cattle-exclusion fence but funds were taken prior to completion of the fence and the project was not completed (Dietz 2011, pers. comm.). The introduced site at Mill Creek Gardens was created in 1995 as a conservation easement by a private donor (SFASU 1999, p.1) and was used as an experimental plot to test fertilizer and mulching effects on the rose-mallow (Scott 1997, pp. 6-7). This site is informally managed through mowing and burning regimes prescribed by SFASU staff, but encroachment from native woody species has been observed in the past (Creech 2011c, pers. comm.). Due to a lack of accessibility, the two remaining private properties, the Harrison County site and Camp Olympia have not been observed since 1980 and 1992, respectively (Warnock 1995, pp. 6, 8; TXNDD 2012a, pp. 58-60).
Summary of Factor A
Based on our evaluation of the best available information, we conclude that the present loss and modification of the rose-mallow's habitat is a significant threat to the species' continued survival. Threats include competition for light and nutrients by invasive plant species, particularly chinese tallow, altered hydrology, and herbicide drift; these threats may be exacerbated by future road and bridge construction and maintenance work. We determine that livestock grazing and feral hogs are not significant threats to the species. Although silvicultural practices have caused some prior impacts to the species, we do not anticipate that silviculture will continue to be a significant threat. The exploration and development of oil and natural gas wells, and predicted effects of climate change, are not currently threats to the species, but do represent potential future stressors. Additional conservation measures that had protected habitat and certain actions on privately owned land have expired and no longer provide protection to habitat of the rose-mallow. Therefore, we conclude that the rose-mallow faces significant threats due to habitat loss, destruction, modification, or curtailment of the species' habitat or range.
B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes
The showy flowers produced by the genus
Hibiscus
make it of high horticultural interest (USFWS 2010a, p. 8) to
Hibiscus
enthusiasts (Warnock 1995, p. 25; Poole
et al.
2007, p. 265). Hybridization within genus
Hibiscus
is repeatedly done in the nursery trade (Creech 2011a, pers. comm.) to produce different colored flowers and modify other traits that may be of commercial interest. Ornamental landscaping companies sell rose-mallow plants online (Creech 2011a, pers. comm.). Rose-mallow plants are easy to cultivate from cuttings, and having plants available for sale in the nursery trade reduces collecting pressures of the species from the wild (Creech 2011a, pers. comm.). Plantings of rose-mallow into garden settings are standard and placement within close proximity to wild populations has not been recorded or observed.
Mercer Arboretum collected seed in 1993, 1994, 1996, 1997, and 2003; these seeds, as well as living plants, are being maintained at the Mercer Arboretum (Tiller 2011, pers. comm.). A portion of the seeds collected were grown out in the Arboretum's Rare and Endangered Gardens, where they have remained; seeds and plants have not been transplanted back into the wild populations (Tiller 2011, pers. comm.). Rose-mallow seed was also sent to the National Seed Storage Laboratory in Fort Collins, Colorado, for long-term storage for conservation purposes (Ellis 2011, pers. comm.).
The scientific and horticultural communities have collected rose-mallow seeds and plants from wild populations; however, we have no evidence that suggests that collection has depleted the seed bank or has adversely affected populations. Plants are easily cultivated and the species is well established as a nursery trade plant, thereby reducing potential collection pressure. Based on the best available information, we conclude that collection for recreational, scientific, or educational purposes is not a threat to the rose-mallow and is not likely to increase in the future.
C. Disease or Predation
Leaves and stems of plants in the
Hibiscus
family (Kroll 1991, p. 392; Everitt
et al.
1999, pp. 177-193) are often consumed by white-tailed deer (
Odocoileus virginianus
) (Moreland 2005, p. 48). Cattle also consume the stems but to a lesser degree than white-tailed deer (Everitt
et al.
1999, pp. 187-193). In 1993, evidence of herbivory was present at four rose-mallow subpopulations at Lovelady (Warnock 1995, p. 18) and in 2010, at compartment 20 (Allen and Duty 2010, p. 3). In 2011 at 5 of the 11 populations, above-ground portions of the rose-mallow, mainly the tips, were grazed by white-tail deer, with the most intense herbivory occurring at the Lovelady site. Plants consumed by deer could decrease the reproductive success of the rose-mallow (Adler
et al.
2001, p. 1). Only at the compartment 20 on the Davy Crockett NF was the evidence of browsing on the flowers observed (Allen and Duty 2010, p. 3); however, the species is able to produce secondary growth (Strauss and Agrawal 1999, p. 179). Drought could exacerbate the consumption of leaves and stems if preferred plants were not available, but we conclude that ungulate (hoofed animal) herbivory is an insignificant stressor to the rose-mallow.
Insect damage and predation has been observed on rose-mallow plants in several populations; however, regrowth of foliage after herbivory incidents may indicate that the rose-mallow is adapted to herbivory (Strauss and Agrawal 1999, p. 179). Ninety percent of the first foliage of rose-mallow leaves at Lovelady had been consumed by insects (USFWS 2010a, p. 8) with insect predation also seen on compartment 11 plants in 2006 (Philipps 2009, p. 1). The scentless plant bug was observed on plants in compartment 55 (Miller 2011, pers. comm.). This bug is known to deposit egg masses on stems, leaves,
flower parts, buds, and seed pods of
Hibiscus
species (Wheeler 1977, p. 632), but to also consume
Hibiscus
seeds (Toth 2007, p. 6). Holes were observed on several rose-mallow plants on all NF sites (Miller 2011, pers. comm.) and were likely caused by this plant bug; however, these bugs are not considered a significant pest because the damage to the plants is minor (Toth 2007, p. 6). Larval forms of the Hibiscus sawfly (
Atomacera decepta
) can consume rose-mallow seed pods in herbaria, but have not been noted to affect wild populations (Wieland 1995, p. 1; Creech 2011a, pers. comm.).
Changes in precipitation are not well understood in relationship to insect herbivory (Bale
et al.
2002, p. 2). Drought conditions may exacerbate consumption of the vegetative and floral parts if other food resources within the plant community become scarce. Temperature shifts related to climate change may trigger corresponding insect population shifts. Impacts from insect population shifts cannot be predicted; however, if conditions favor the growth of insect populations, the effects of insect herbivory on the rose-mallow could increase.
Summary of Factor C
Mammalian herbivory has affected the majority of sites; however, grazing pressures are largely attributed to the lack of other available food resources during periods of drought. Rose-mallow recovers quickly from herbivory incidents and can produce secondary growth, minimizing the overall negative effects of mammalian herbivory. This type of herbivory is not considered to be a threat to the species. Insect herbivory was also observed on several of the sites and was not range-wide but, with anticipated climate change shifts in temperature and the likelihood that insect populations will increase, we conclude that insect predation is a minor stressor that will likely continue into the future.
D. The Inadequacy of Existing Regulatory Mechanisms
Under this factor, we examine whether existing regulatory mechanisms are inadequate to address the threats to the species discussed under the other factors. Section 4(b)(1)(A) of the Act requires the Service to take into account “those efforts, if any, being made by any State or foreign nation, or any political subdivision of a State or foreign nation, to protect such species * * *” In relation to Factor D under the Act, we interpret this language to require the Service to consider relevant Federal, State, and tribal laws, regulations, and other such mechanisms that may minimize any of the threats we describe in threat analyses under the other four factors, or otherwise enhance conservation of the species. We give strongest weight to statutes and their implementing regulations and to management direction that stems from those laws and regulations. An example would be State governmental actions enforced under a State statute or constitution, or Federal action under statute.
Having evaluated the significance of the threat as mitigated by any such conservation efforts, we analyze under Factor D the extent to which existing regulatory mechanisms are inadequate to address the specific threats to the species. Regulatory mechanisms, if they exist, may reduce or eliminate the impacts from one or more identified threats. In this section, we review existing State and Federal regulatory mechanisms to determine whether they effectively reduce or remove threats to the rose-mallow.
Davy Crockett NF lands are federally owned and managed by the USDA Forest Service for the general public. Four populations of the rose-mallow occur on the Davy Crockett NF. The NF classifies the rose-mallow as a Regional Forester's Sensitive Species (Philipps 2012, pers. comm.) and habitat is within Management Area Zone 4, according to the Revised Land and Resource Management Plan (1996). This management zone includes the bed, bank, and water resources of the rivers, perennial and intermittent streams and wetlands, and their adjacent areas (USDA 1996, p. 145). This area is managed to maintain the role and function of aquatic, riparian, and wetland ecosystems while providing opportunities for compatible multiple uses and will be managed to meet recommendations stated in the Texas Wetland Plan (TPWD 1988) and Best Management Practices established by the State (USDA 1996, p. 151). Relative Management Area Zone 4 standards and guidelines include: Maintenance or restoration of native plant communities; prohibition of nonaquatic herbicide uses except hand applications or noxious weed control following restriction on the herbicide label; and use of prescribed fire when necessary to enhance riparian vegetation or wildlife habitat (USDA 1996, pp. 153, 155). Herbicides are not currently being used on the Davy Crockett NF and have been replaced by prescribed fire, with the goal of routinely burning compartments every 3 years (Stiles 2011, pers. comm.). As discussed previously (see
Factor A;
Nonnative Species), routine fires may play a role in reducing chinese tallow. Actions that may affect rose-mallow habitat need to be assessed using these standards and guidelines because these are considered regulations that need to be followed (Phillips 2012, pers. comm.). The encroachment of nonnative and native vegetation in rose-mallow habitat is not addressed in the Revised Land and Resource Management Plan; however, the application of prescribed fire in some areas may benefit the r
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