Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition to List Cirsium wrightii (Wright's Marsh Thistle) as Endangered or Threatened, 67925-67944 [2010-27740]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 75, Number 213 (Thursday, November 4, 2010)]
[Proposed Rules]
[Pages 67925-67944]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-27740]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2009-0060; MO 92210-0-0008]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition to List Cirsium wrightii (Wright's Marsh Thistle) as 
Endangered or Threatened

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service, announce a 12-month 
finding on a petition to list Cirsium wrightii (Wright's marsh thistle) 
as endangered or threatened and to designate critical habitat under the 
Endangered Species Act of 1973, as amended. After review of all 
available scientific and commercial information, we find that listing 
C. wrightii as endangered or threatened throughout its range is 
warranted. Currently, however, listing of C. wrightii is precluded by 
higher priority actions to amend the Lists of Endangered and Threatened 
Wildlife and Plants. Upon publication of this 12-month petition 
finding, we will add C. wrightii to our candidate species list. We will 
develop a proposed rule to list C. wrightii as our priorities allow. We 
will make any determination on critical habitat during development of 
the proposed rule. In the interim period, we will address the status of 
the candidate taxon through our annual Candidate Notice of Review.

DATES: The finding announced in this document was made on November 4, 
2010.

ADDRESSES: This finding is available on the Internet at https://www.regulations.gov at Docket Number FWS-R2-ES-2009-0060. Supporting 
documentation we used in preparing this finding is available for public 
inspection, by appointment, during normal business hours by contacting 
the U.S. Fish and Wildlife Service, New Mexico Ecological Services 
Office, 2105 Osuna NE, Albuquerque, NM 87113. Please submit any new 
information, materials, comments, or questions concerning this finding 
to the above address.

FOR FURTHER INFORMATION CONTACT: Wally ``J'' Murphy, Field Supervisor, 
U.S. Fish and Wildlife Service, New Mexico Ecological Services Field 
Office (see ADDRESSES); by telephone at 505-346-4781; or by facsimile 
at 505-346-2542. If you use a telecommunications device for the deaf 
(TDD), please call the Federal Information Relay Service (FIRS) at 800-
877-8339.

SUPPLEMENTARY INFORMATION: 

Background

    Section 4(b)(3)(B) of the Endangered Species Act (Act) (16 U.S.C. 
1531 et seq.) requires that, for any petition to revise the List of 
Endangered and Threatened Wildlife that contains substantial scientific 
and commercial information that listing may be warranted, we make a 
finding within 12 months of the date of receipt of the petition on 
whether the petitioned action is: (a) Not warranted, (b) warranted, or 
(c) warranted, but the immediate proposal of a regulation implementing 
the petitioned action is precluded by other pending proposals to 
determine whether species are threatened or endangered, and expeditious 
progress is being made to add or remove qualified species from the 
Federal Lists of Endangered and Threatened Wildlife and Plants. Section 
4(b)(3)(C) of the Act requires that we treat a petition for which the 
requested action is found to be warranted but precluded as though 
resubmitted on the date of such finding, that is, requiring a 
subsequent finding to be made within 12 months. We must publish these 
findings in the Federal Register.

Previous Federal Actions

    On October 15, 2008, we received a petition from the WildEarth 
Guardians, dated October 9, 2008, requesting that

[[Page 67926]]

we list Cirsium wrightii (Wright's marsh thistle) as endangered or 
threatened under the Act. Additionally, the petitioner requested that 
critical habitat be designated concurrent with listing of C. wrightii. 
In a November 26, 2008, letter to the petitioner, we responded that we 
had reviewed the petition and determined that an emergency listing was 
not necessary. We also stated that, to the maximum extent practicable, 
we would address their petition within 90 days.
    The petition asserted that water diversion, habitat loss and 
degradation through current livestock grazing, inadequate regulatory 
mechanisms, weed control, nonnative species, drought, and climate 
change threaten C. wrightii. During our review of the petition, we 
found that the majority of information cited in the petition was not 
readily available to us. Therefore, on December 18, 2008, we requested 
that the petitioner provide references. On February 13, 2009, the 
petitioner provided additional references.
    On September 10, 2009, we published a 90-day finding in the Federal 
Register that the petition presented substantial information that 
listing C. wrightii may be warranted. That document also initiated a 
status review of the subspecies (74 FR 46542). On February 11, 2010, 
WildEarth Guardians filed suit against the Service for failure to issue 
a 12-month finding on the petition (WildEarth Guardians v. Salazar, No. 
10-cv-00122 BRB-DJS (D.N.M.)). Pursuant to a stipulated settlement 
agreement, the 12-month finding is due to the Federal Register by 
October 31, 2010. This notice constitutes our 12-month finding for the 
petition to list C. wrightii as threatened or endangered with critical 
habitat.

Species Information

    Cirsium wrightii is a biennial (a plant completing development in 2 
years, flowering its second year) or a weak monocarpic perennial (a 
plant that flowers, sets seed, then dies), in the sunflower family 
(Asteraceae). The plant is prickly with short black spines and a 3- to 
8-foot (ft) (0.9- to 2.4-meter (m)) single stalk covered with succulent 
leaves (Sivinski 1996, p. 1; Arizona Game and Fish Department (AGFD) 
2001, p. 1). Numerous slender flowering branches emerge from the stalk, 
starting about one-third up the length of the plant. Branches are 
terminated by one or a few small flowering heads, which have numerous 
slender phyllaries (a modified leaf associated with the flower) 
(Sivinski 1996, p. 1). Flowers are white to pale pink in areas of the 
Sacramento Mountains of New Mexico, but are vivid pink in the Santa 
Rosa, New Mexico, locality (Sivinski 1996, p. 1). In New Mexico, the 
species occurs in wet, alkaline soils in spring seeps and marshy edges 
of streams and ponds between 3,450 and 7,850 ft (1,152 and 2,393 m) in 
elevation (Sivinski 1996, p. 1; 2005a, pp. 3-4; Worthington 2002a).
    Cirsium wrightii is a wetland obligate (occurs only in water-
saturated soils) that was originally collected in 1851 at San 
Bernardino Cienaga, Cochise County, Arizona (Gray 1853, p. 101; 
Smithsonian 1849, p. 1). Historically, the species was found in 
Arizona, New Mexico, and Chihuahua, Mexico (Gray 1853, p. 101; Coulter 
1891, p. 244; Kearney and Peebles 1951, p. 952; Correll and Johnston 
1970, p. 1719; U.S. Fish and Wildlife Service (Service) 1995, p. 1). 
Recently it was learned that an occurrence of another sunflower, 
Cirsium texanum (Texas thistle), in Presidio County, Texas, had been 
incorrectly identified as C. wrightii (Poole 2010, p. 1). All of the 
previously presumed specimens of C. wrightii from Texas have now been 
correctly identified as Cirsium texanum (Texas thistle), rather than C. 
wrightii (Sivinski 1994a, p. 1; 1996, p. 2; 2006a, p. 1; Worthington 
2002a, p. 4). These species are easily confused on herbarium sheets 
(Sivinski 1996, p. 2). However, in the field, C. wrightii differs from 
C. texanum in physical appearance (New Mexico Rare Plant Technical 
Council (NMRPTC) 2009, p. 1)). The presumed Texas specimens of C. 
wrightii that were previously identified from herbarium sheets, rather 
than field identification, have been found to be C. texanum (Sivinski 
1996, p. 2).
    In the New Mexico portion of the species' range, Cirsium wrightii 
appears to be an obligate of seeps, springs, and wetlands that have 
saturated soils with surface or subsurface water flow (Sivinski 1996; 
Service 1998; Worthington 2002a, p. 2; NMRPTC 2009). Plants commonly 
found in areas inhabited by this species include Scirpus spp. 
(bulrush), Salix spp. (willow), Baccharis glutinosa (seepwillow), 
Helianthus paradoxus (Pecos sunflower), Juncus spp. (rush), and Typha 
spp. (cattail) (Sivinski 1996, pp. 2-5; Sivinski and Bleakly 2004, p. 
2; Worthington 2002a, pp. 1-2).

Distribution and Range

    Cirsium wrightii currently occurs in New Mexico; however, it has 
been extirpated from all previously known locations in Arizona 
(Sivinski 1996, pp. 1, 4, 9, 2006a, 2009a, p. 1; Worthington 2002a, p. 
4), and was misidentified and likely not ever present in Texas (Poole 
1992; 2010; Sivinski 1996, p. 2). The status of the species in Mexico 
is uncertain, with few verified collections of the plant. Numerous 
surveys of potential habitat have been conducted over the years with 
few new localities documented (e.g., Poole 1992, 2010; Sivinski 1994, 
1996, 2005, 2009a; Worthington 2002a).
    Cirsium wrightii is ranked by NatureServe as a G2 (imperiled) 
species. It was changed from G3 (vulnerable) to G2 in 2003 (NatureServe 
2009, p. 1). Similarly, its National Status ranking for the United 
States is N2 (imperiled due to a restricted range and very few 
populations) (NatureServe 2009, p. 2). Though these rankings do not 
provide any regulatory protections, the NatureServe designations do 
serve to notify the public of the species' status.
    In New Mexico, there are eight general confirmed locations of 
Cirsium wrightii: Santa Rosa, Guadalupe County; Bitter Lake National 
Wildlife Refuge (BLNWR), Chaves County; Blue Spring, Eddy County; La 
Luz Canyon, Karr Canyon, Silver Springs, and Tularosa Creek, Otero 
County; and Alamosa Creek, Socorro County (Bridge 2001, p. 1; Sivinski 
and Bleakly 2004, p. 2; NMRPTC 2009, p. 1; Sivinski 1994, p. 1; 1996, 
p. 2; 2005, p. 1; 2005a, pp. 3-5; 2009, 2009a; Service 1998, p. 1; 
Worthington 2002, p. 1; 2002a, pp. 1-3). Four of the eight localities 
are clustered within about 10 miles (mi) (16 kilometers (km)) of each 
other on the west slope of the Sacramento Mountains, Otero County, 
whereas the remaining four localities are widely disjunct, separated 
from the Sacramento localities by about 75 to 140 mi (120 to 225 km) 
and from each other by about 75 to 215 mi (120 to 345 km). In the 
Sacramento Mountains, two of these four localities occur on the Lincoln 
National Forest, one locality is on private land and the remaining 
locality is on the Mescalero Apache Reservation. In the Pecos River 
Valley, one locality is on public lands on the BLNWR, Chaves County; 
one is on private land near the Black River, Eddy County; and one is in 
the vicinity of Santa Rosa, Guadalupe County, on private, municipal, 
and State lands. The remaining locality is on private land on Alamosa 
Creek, Socorro County. Localities vary in relative population size from 
less than 20 individuals covering only about 50 square feet (ft\2\) ((5 
square meters (m\2\)) at the Silver Springs locality, to several 
thousand individuals on BLNWR.
    Within New Mexico, historic localities from the City of Roswell 
land, Chaves County, Lake Valley in Sierra County, and La Luz and 
Haynes Canyons in Otero County are extirpated

[[Page 67927]]

(NMRPTC 2009, p. 2; Sivinski 2005, p. 1; 2005a p. 4; 2009a, p. 2). 
Finally, a Cirsium species at Rattlesnake Springs, Eddy County, is 
thought to be a hybrid between C. wrightii and C. texanum (NMRPTC 2009, 
p. 2). This population blooms in May rather than the typical season of 
C. wrightii from August to October (NMRPTC 2009, p. 2).
    We are unaware of specific long-term monitoring data on absolute 
abundance estimates for Cirsium wrightii in New Mexico, but have 
estimates of relative abundance for most extant localities (see also 
Sivinski 1996, 2005a, 2006a, 2009, 2009a). In 1996, Sivinski completed 
a status assessment of C. wrightii in New Mexico (Sivinski 1996). He 
subsequently continued to survey and monitor C. wrightii localities. 
Worthington (2002a) conducted surveys at 12 sites that contained 
suitable habitat in Karr Canyon, the Rio Penasco drainage, and in the 
vicinity of Sacramento Lake in the Sacramento Mountains on U.S. Forest 
Service (Forest Service) land in 2002. Moreover, he surveyed additional 
springs, but found most springs were capped or captured for municipal 
use by the City of Alamogordo (Worthington 2002a, p. 3). No new C. 
wrightii populations were found, although one possible new locality 
with plants that lacked the characteristic black tips and had different 
looking leaves was noted (Worthington 2002). However, the locality was 
not photographed, collected, or verified and the accuracy of its 
identification is unknown.
    In Arizona, the Service has similarly contracted surveys of 
potential Cirsium wrightii habitat to verify whether any populations 
are extant. These will be completed by October 2010. Below, we present 
information on all of the known historic and extant localities of C. 
wrightii rangewide, including those that have been extirpated.

New Mexico

Tularosa Creek
    The Tularosa Creek, Otero County, population of Cirsium wrightii 
occurs on private land and the Mescalero Apache Reservation. This 
population has significantly declined since 1995, from an estimated 
several thousand individual plants along 3.5 mi (5.6 km) of nearly 
continuous occupied marsh and wet meadows, to four scattered occupied 
locales of less than 50 individual flowering plants total along the 
same stretch in 2009 (Sivinski 1996, p. 3; 2009a, p. 2). In 1995, this 
was the most extensive population in the Sacramento Mountains, but it 
has become drier and dominated by the invasive plant Phragmites 
australis (common reed) since the 1995 survey (Sivinski 1996, p. 3; 
2009a, p. 2). This population likely includes additional small adjacent 
localities of scattered individual plants on the Mescalero Apache 
Reservation, but we were unable to survey these Tribal lands (e.g., see 
Bridge 2001; Worthington 2002a). Moreover, the possible new locality 
found by Worthington (2002) occurs in the area.
La Luz Canyon
    The small La Luz Canyon population of Cirsium wrightii that occurs 
within about 540 ft\2\ (50 m\2\) of spring habitat on Forest Service 
lands was stable at an estimated 50 plants both in 1995 and 2005 
(Sivinski 1996, p. 3; 2005a, p. 4). However, an adjacent small 
population of 10 plants in the same general area on private land 3 mi 
(5.8 km) east of La Luz Canyon was extirpated between 1995 and 2005, 
most likely from a severe scouring flood and alteration of the spring 
hydrology that led to the drying of habitat (Sivinski 2005a, p. 4; 
2009a, p. 2).
Karr Canyon
    The Karr Canyon/Haynes Creek population of Cirsium wrightii 
previously included a cluster of a hundred plants within about 1000 
ft\2\ (100 m\2\) of spring habitat within a highway right-of-way that 
was stable between 1995 and 2005 (Sivinski 1996, p. 2, 2005a, p. 4). 
Nevertheless, a small population of a few dozen mature plants in the 
same general area on private land was extirpated between 1995 and 2005 
and replaced by Phragmites australis (Sivinski 1996, p. 2, 2005a, p. 4; 
2009a, p. 2).
Silver Springs Canyon
    The small Silver Springs Canyon population of Cirsium wrightii 
occurs on Forest Service land in a wet meadow and was estimated at 16 
mature plants in 2002 (Worthington 2002, p. 4; 2002a, p. 15). The 
population was observed in July 2010 and appears to be approximately 
the same size (Service 2010b, p. 1). This population is growing within 
a seep and is adjacent to C. vinaceum (Sacramento Mountains thistle) 
(Worthington 2002, p. 4).
Bitter Lake National Wildlife Refuge
    A large population of Cirsium wrightii was found at BLNWR in 1998 
and is associated with cienagas (wet meadows) and marshes in Units 3, 
5, and 6 of the refuge (Service 1998, p. 1; 2010, p. 1). All known 
populations of C. wrightii on BLNWR grow within designated critical 
habitat of Helianthus paradoxus (Service 2010a, p. 6). When C. wrightii 
was discovered on BLNWR, the population was estimated between 1,680 and 
2,130 flowering plants (Service 1998, p. 1; 1999, p. 25). Sivinski 
(2005a, p. 3) found there was no change in this population's 
distribution and abundance between 1999 and 2005. In 2009, the 
population was estimated to be thousands of individuals, the largest 
known population of C. wrightii (Sivinski 2009a, p. 2).
Roswell
    Cirsium wrightii historically occurred in North Spring, at the 
Roswell Country Club, Roswell, New Mexico (Sivinski 1996, p. 4). 
However, the population has been extirpated following the alteration 
and loss of all vegetation, including C. wrightii, as a result of the 
enclosure of North Spring with bricks and cement (Sivinski 1996, p. 4; 
New Mexico Department of Game and Fish (NMDGF) 2005a, p. 18). Sivinski 
surveyed most of the springs in the vicinity of Roswell in 1995 looking 
for C. wrightii populations (Sivinski 1996, p. 4). All but one spring 
had been capped and diverted for domestic water, and no extant or new 
populations were found (Sivinski 1996, p. 4).
Santa Rosa Wetlands
    The Santa Rosa area is a zone of karst topography (an area of 
erosive limestone), with numerous sinkhole lakes and artesian springs 
(ground water that is under pressure) within a 6-mi (9.7-km) diameter 
circular depression. The localities of C. wrightii are scattered within 
some of the marshes, spring seeps, and various sinkhole lakes, with 
flowering plants generally rare and occurring throughout 4 sections 
spread out over 4 square miles (mi\2\) (10 square kilometers (km\2\)) 
on a mixture of State, private, and municipal lands, but the total area 
occupied in this locality is less than 5 acres (ac) (2 hectare (ha)) 
(Sivinski 1996, p. 4; Sivinski and Bleakly 2004, pp. 1, 3; Service 
2010c, pp. 1-2). For example, the 116-ac (47-ha) Blue Hole Cienaga 
locality, owned by the State of New Mexico, is part of the overall 
population and contains sparse occurrences (i.e., not continuous in 
distribution) of C. wrightii along a spring-fed creek and an adjacent 
seep (Sivinski and Bleakly 2004; Service 2010c). The other known 
localities in the area include El Rito Creek, private lands, ponds at a 
no-longer-used fish hatchery, Bass Lake, and Perch Lake (a large 
sinkhole that is partially developed for fishing and picnicking) 
(Sivinski 1996; 2005a; 2010a; Sivinski and Bleakly 2004). Most of the

[[Page 67928]]

municipal habitats are small, but have been filled and developed for 
recreation. This active filling of wetlands has led to the loss of C. 
wrightii plants in recent years (Service 2010c). These localities 
support perhaps a few hundred C. wrightii, but the remaining localities 
are smaller, isolated occurrences (Sivinski 1996, p. 6, 2009a; 2010a, 
p. 1; Sivinski and Bleakly 2004, p. 3). Between 1995 and 2005, the 
overall Santa Rosa population was thought to be stable, estimated at 
several thousand plants (Sivinski 1996, p. 4; 2005a, p. 3).
Blue Spring
    A new population of Cirsium wrightii was discovered in 2009 at Blue 
Spring, Eddy County, New Mexico (Sivinski 2009). This population was 
estimated at several hundred to a few thousand plants and occupies 
about 1 mi (1.6 km) of riparian habitat (Sivinski 2009, p. 1). Water 
flow at Blue Spring is generally perennial along the 2.5-mi (4-km) run 
that flows into the Black River (a tributary of the Pecos) near Black 
River Village, New Mexico (NMDGF 2007, p. 15). We have no other 
information on this locality, as it was just discovered in 2009.
Alamosa Springs
    Another population of Cirsium wrightii was discovered in 2005 at 
Alamosa Springs, Socorro County, New Mexico (Sivinski 2005, p. 1). 
There were an estimated 500-1,000 flowering adults and rosettes 
confined to a small, spring-fed wetland within the Alamosa Creek Valley 
(a tributary of the Rio Grande), but none of the plants occurred along 
Alamosa Creek (Sivinski 2005, p. 1; 2010a, pp. 1-2). The remaining 
springs in the Alamosa Creek Valley are on private land and have not 
been surveyed.
Lake Valley
    A population of Cirsium wrightii was historically located within 
Lake Valley, Sierra County, New Mexico, but is considered extirpated 
(Sivinski 2005). This site is now an abandoned mining settlement, but 
was historically a series of marshes and cienagas. The area was diked, 
channeled, and drained in the early 1900s and converted to row-crop 
agriculture (Sivinski 2005, p. 1). There is no longer suitable habitat 
for C. wrightii within the valley (Sivinski 2005, p. 1).

Arizona

San Bernardino Cienaga
    The population at the type locality (the place where the species 
was first found) from San Bernardino Cienaga, Arizona, has not been 
found again since it was originally collected in 1851, although the 
area was surveyed in 2006 by The Nature Conservancy (Sivinski 2006a, p. 
1; 2009a, p. 1). The species is likely extirpated from the State (ADGF 
2001, p. 1; Sivinski 1996, p. 4; 2009a, p. 1; Service 2009a, p. 1).

Texas

    We found that Cirsium specimens from Texas have been confused 
because of the difficulty in distinguishing Cirsium wrightii and C. 
texanum from herbarium sheets (Sivinski 1994, p. 1; 1994a, p. 1; 
Sivinski 2006a, p. 1). All of the collections from herbariums and 
references identifying C. wrightii localities in Texas are in error 
(Coulter 1881, p. 244; Correll and Johnson 1970, p. 1719; Kearney and 
Peebles 1951, p. 952; Martin and Hutchins 1981, p. 2002; Sivinski 1994, 
p. 1; 1996, p. 5; Texas A&M University 1975, p. 89). Furthermore, the 
presumed location from Presidio, Texas, that we identified in the 90-
day finding (74 FR 46544), is not C. wrightii, but most likely an 
undescribed species from northern Mexico (Poole 2010, p. 1).
    Poole (1992) evaluated 74 cienagas in Texas and conducted botanical 
surveys at 33 of the locations within the highest potential habitat 
(i.e., springs and wetlands) for the Helianthus paradoxus, which has 
similar habitat requirements and sometimes overlaps with C. wrightii. 
No C. wrightii locations were found during these extensive botanical 
surveys (Poole 1992). Similarly, we reviewed information from and 
contacted botanists who have surveyed the Diamond Y Preserve, Pecos 
County, Texas, owned by The Nature Conservancy. This preserve shares 
some of the same habitat characteristics, and many of the imperiled 
species, found on BLNWR, including Pecos assiminea (Assiminea pecos), 
Pecos gambusia (Gambusia nobilis), and Helianthus paradoxus (Service 
2005, pp. 4, 8; 2007, p. 10; Poole 2010, p. 1). We found that Diamond Y 
has been thoroughly surveyed, and it does not appear that C. wrightii 
occurs on the preserve. Because we do not have any verified historic 
collections or known extant populations from any locations in Texas 
(Poole 2010, p. 1; 2010a, p. 1), we conclude that C. wrightii has never 
been present within the State.

Mexico

    We have not been able to obtain any recent information on Cirsium 
wrightii in Mexico. In fact, we have located only three herbarium 
specimens that were collected in Mexico. One specimen was collected in 
1982 at Cerro Angostura Spring, Chihuahua, Mexico (Sivinski 2009a, p. 
1, 2010; CONABIO 2010). The second collection from Los Azules, 
Chihuahua, in 1998, was misidentified and is not C. wrightii. The third 
collection from Fronteras, Sonora, in 1890, has not yet been verified 
(Sivinski 2010, p. 1). As such, the status of the species in Mexico is 
uncertain.
    In summary, there are eight general localities of Cirsium wrightii 
extant within New Mexico. Additional historical populations have been 
extirpated, including at least two larger and two smaller populations 
in New Mexico, and there are no known extant populations in Arizona. 
The population at BLNWR is likely the most robust, with several 
thousand individuals. Santa Rosa contains mostly sparse scattered 
localities throughout four sections of land, and some of these have 
been extirpated recently. The population along Tularosa Creek has 
undergone a significant reduction since 1995. The remaining populations 
in the Sacramento Mountains are all small, containing from 15 to 
perhaps several hundred individuals. The populations at Blue Spring and 
Alamosa Springs were recently discovered, and there have been no 
subsequent surveys to determine whether these populations are stable or 
declining. The collections from Texas were misidentified, and we 
conclude C. wrightii never occurred in the State. Finally, there is 
only one verified historic collection from Mexico, and no recent 
information on the status of the species from this population. For 
these reasons, the status of this species remains tenuous.

Summary of Information Pertaining to the Five Factors for Cirsium 
wrightii

    Section 4 of the Act and implementing regulations (50 CFR part 424) 
set forth procedures for adding species to the Federal Lists of 
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of 
the Act, a species may be determined to be endangered or threatened 
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; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    In making this finding, information pertaining to Cirsium wrightii, 
in relation to the five factors provided in section 4(a)(1) of the Act, 
is discussed below.

[[Page 67929]]

    In making our 12-month finding on a petition to list Cirsium 
wrightii, we considered and evaluated the best available scientific and 
commercial information. This information includes the petition and 
associated documents, data from the 1995 through 2009 surveys and 
recent reports (Sivinski 1996, 2005a, 2006a, 2009, 2009a; Forest 
Service 2008b; Service 2010b, 2010c), as well as other information 
available to us. The following analysis examines the five factors 
described in section 4(a)(1) of the Act and those activities and 
conditions currently affecting C. wrightii, or are likely to affect the 
species within the foreseeable future.
    In considering what factors might constitute threats to a species, 
we must look beyond the exposure of the species to a particular factor 
to evaluate whether the species may respond to that factor in a way 
that causes actual impacts to the species. If there is exposure to a 
factor and the species responds negatively, the factor may be a threat 
and, during the status review, we attempt to determine how significant 
a threat it is. The threat is significant if it drives, or contributes 
to, the risk of extinction of the species such that the species 
warrants listing as endangered or threatened as those terms are defined 
in the Act. However, the identification of factors that could impact a 
species negatively may not be sufficient to compel a finding that the 
species warrants listing. The information must include evidence 
sufficient to suggest that these factors are operative threats that act 
on the species to the point that the species may meet the definition of 
endangered or threatened under the Act.

A. Present or Threatened Destruction, Modification, or Curtailment of 
the Species' Habitat or Range

    The most significant threat to Cirsium wrightii is the alteration 
of the hydrology of its rare wetland habitat. In fact, much of the 
habitat of C. wrightii has been and continues to be severely altered 
and degraded because of past and present land and water management 
practices including: agriculture and urban development, diversion of 
springs, and drought. As described below, all of the extant localities 
may be affected by long-term drought, whereas four of the largest C. 
wrightii localities at Blue Spring, BLNWR, Santa Rosa, and Alamosa 
Creek have the potential to be further modified by ongoing and future 
water withdrawal. Changes in water tables throughout the range of C. 
wrightii have often resulted in diminished discharge from springs or 
complete loss of surface water. Therefore, there has been a trend of 
diminishing habitat quantity and excessive degradation of habitat 
quality for the species throughout its range.
Availability of Water
    Cirsium wrightii is found in association with seeps, springs, 
marshes, and wetlands that have saturated soils with surface or 
subsurface water flow (NMRPTC 2009; Sivinski 1996, pp. 2-7; Service 
1998, p. 2; Worthington 2002a, p. 2). Southwestern riparian and aquatic 
systems fluctuate due to seasonal and longer term drought and wet 
periods, floods, and fire. Habitats with fluctuating water levels 
create circumstances in which population sizes may vary over time, and 
populations may be periodically extirpated. Because the species occurs 
only in areas that are water-saturated, populations have a high 
potential for extirpation when habitat dries due to ground and surface 
water depletion, draining of wetlands, or drought. Loss of water from 
C. wrightii habitat occurs through changing precipitation patterns, 
drought, or as a result of human impacts from groundwater pumping 
(withdrawal) or diversion of surface water; this can lead to the 
degradation and extirpation of Cirsium wrightii habitat (Sivinski 1996, 
p. 5; 2005, p. 1; Forest Service 2008, p. 19). Moreover, the drying of 
C. wrightii habitat has led to retractions of occurrence boundaries, a 
reduction in the numbers of plants, and, in some cases, a loss of all 
individuals at several localities (Sivinski 2005a, pp. 3-4). For 
example, during the dry conditions from 1994 to 1996, many seeps and 
springs in the Sacramento Mountains ceased flowing and were completely 
dry (Sivinski 2006b, p. 12). Naturally occurring water loss from 
changes in precipitation patterns have affected the volume of water 
flow at numerous springs in the Sacramento Mountains (Forest Service 
2003, p. 43).

Drought

    The National Weather Service Forecast Office and the U.S. Drought 
Monitor for New Mexico indicate that the Sacramento Mountains 
experienced a severe to extreme drought from 2003 to 2008 (Forest 
Service 2008, p. 22). This has led to unusually low stream or spring 
flows and, in some instances, no flow (e.g., see South Central Mountain 
2002, p. 12; Shomaker 2006, p. 8; Gardner and Thompson 2008, p. 2; 
Newton et al. 2009; Sivinski 2005a, pp. 3-4, Forest Service 2003, pp. 
53-54). This is likely related to severe drought conditions (Sivinski 
2005a, pp. 1, 3-4). Within New Mexico, monsoonal summer precipitation 
can be very patchy, with some areas receiving considerably less 
rainfall than others. Newton et al. (2009) studied the hydrogeology of 
the Sacramento Mountains and found that the fractures in the underlying 
geology exhibit significant control on surface and groundwater flow and 
possibly groundwater recharge. Overall, their data suggest that the 
recharge of water wells and groundwater is correlated to the amount of 
precipitation during monsoon storms at all elevations (Newton et al. 
2009, p. 22). Wet periods during summer months can significantly 
contribute to recharge of the ground water in the Sacramento Mountains, 
but these are extremely rare events (Newton et al. 2009). As such, 
drought has impacted the recharge of ground water tables throughout the 
Sacramento Mountains (Forest Service 2008, p. 22). For this reason, the 
seasonal distribution of yearly precipitation can result in temporary 
drought conditions and reduced water availability for some C. wrightii 
localities within this mountain range.
    In 1995 and 2005, Sivinski (2005a, pp. 3-4) monitored the relative 
size of Cirsium wrightii localities rangewide to document the 
relationship between water availability in suitable habitat and numbers 
and extent of plants. He found that, when some localities dried, the 
localities were either extirpated or much reduced in size (Sivinski 
2005a, pp. 3-4). Moreover, drying of occupied habitat also resulted in 
Typha latifolia (cattail) being replaced by dense stands of Phragmites 
australis (Sivinski 2005a, pp. 3-4), which may outcompete native 
vegetation including C. wrightii and significantly increase the threat 
of wildfire (see discussion below under ``Phragmites australis'').
    Drought also affects the size of an extant locality, even when the 
water source does not dry out completely. The most severe drought 
recorded in New Mexico occurred between 1950 and 1956. If drought 
reduces the amount of groundwater recharge regionally, spring discharge 
or the areal extent of wetlands could also be reduced. Prolonged 
drought can lead to diminishment or drying of springs, which would have 
a negative impact on Cirsium wrightii or its habitat. Comparing 
historical discharges reported in the Black River from 1952 to 1956 
(daily mean flow of 15.4 cubic feet per second (cfs) (0.436 cubic 
meters per second (cms))) to recent discharges (2002 to 2006, daily 
mean flow of 10.1 cfs (0.286 cms)), flows in the Black River are 
currently lower than flows during the extreme drought of the 1950s 
(NMDGF 2007, p.

[[Page 67930]]

26). Prolonged drought could adversely impact habitat conditions by 
reducing hydrologic discharge through the wetland system, thereby 
desiccating riparian plant communities (e.g., see NMDGF 2008, p. 33), 
including C. wrightii. Because of the documented extirpation and 
population reductions of the species caused by drought and the 
possibility of more widespread drought accompanying climate change, we 
conclude that drought constitutes a threat to C. wrightii, both now and 
in the foreseeable future.

Ground and Surface Water Depletion

    Habitat loss due to ground and surface water depletion is a threat 
to Cirsium wrightii. Sivinski (1994, pp. 1-2; 1996, p. 4; 2005, p. 1; 
2006, p. 4) reported loss or degradation of habitat from water 
diversion or draining of wetlands in Chaves, Otero, and Sierra 
Counties, New Mexico, areas that historically supported Cirsium 
wrightii. Increased water extraction in the last 100 years has 
contributed to the dramatic decline of most surface spring systems in 
the Chihuahuan Desert (see Corps 2006, p. 4; Karges 2003 and references 
therein). An historical population in Lake Valley, Sierra County, New 
Mexico, was extirpated when the wetlands were drained and converted to 
agricultural use (Sivinski 2005, p. 1; 2006a, p. 1). Moreover, the 
appropriation of water rights from springs for a ``beneficial use,'' 
such as livestock water, farming, domestic use, or recreational 
facilities, typically uses points of diversion that can curtail natural 
surface flows and affect C. wrightii populations. For example, aquifers 
in the Sacramento Mountains, which contain half of all known C. 
wrightii localities, are susceptible to appropriation by existing water 
rights and development of new water rights, which may pose future 
threats to the species (Service 2008, pp. 12, 23; Forest Service 2008, 
pp. 23-24). The marshes, springs, and seeps within La Luz Canyon of the 
Sacramento Mountains are currently and were likely historically 
diverted or drained for irrigation and agricultural use (Sivinski 1996, 
p. 5; South Central Mountain 2002, p. 20). Many springs and streams in 
the Sacramento Mountains that were perennial during the 1900s have 
become intermittent or have dried completely, including La Luz Creek 
(Abercrombie 2003, p. 3). In this area, loss of water flow from human 
activities related to roads, trails, and the capture of spring water 
for municipal use have also been observed to affect the threatened 
species Cirsium vinaceum (Forest Service 2003, pp. 42-43). The same 
likely holds true for C. wrightii, although it has not been 
specifically investigated.
    The severe decline in available surface and ground water since the 
1990s is due largely to drought and human use (e.g., Shomaker 2006, pp. 
8, 20, 26). Cirsium wrightii occurrences in La Luz Canyon are within 
the municipal supply watershed, where pipelines divert water to the 
City of Alamogordo (Shomaker 2006, pp. 20, 26; Forest Service 2008, p. 
21). The number of water wells drilled on both private and National 
Forest System lands within this area has increased since the 1950s, 
with the 1980s and 1990s being the most active years for drilling of 
domestic use wells (Forest Service 2008, p. 22). The total permitted 
groundwater extraction is approximately 2,400 acre feet per year (300 
hectare-meters per year) (98,000,000 gallons per year) (370,000,000 
liters per year) from nearly 300 wells (Forest Service 2008, p. 22).
    In 2002, the New Mexico State Engineer declared the La Luz Canyon 
watershed as a Critical Management Area, which means no new groundwater 
appropriations would be allowed for nondomestic purposes (Forest 
Service 2008, p. 22). However, for domestic purposes, the demand for 
water use through surface diversion and ground water withdrawals is 
expected to increase as a result of the population increase. The human 
population in Alamogordo, Otero County, New Mexico, increased from 
about 30,000 to 36,000 from 1995 to 2000, and is expected to increase 
to about 56,000 by 2040 (South Central Mountain 2002, p. 11). An 
increasing human population and its associated agricultural and 
economic activities will require additional water from this relatively 
dry region.
    Current New Mexico State law provides that anyone may obtain a 
permit for a domestic well, no matter what the consequences for anyone 
else's water rights or the impact of water resources for the area 
(e.g., see Belin et al. 2003, p. 72). Between 2005 and 2045, the City 
of Alamogordo's water demand is expected to increase from 7,140 acre-
feet per year to 10,842 acre-feet per year (881 hectare-meters per year 
to 1337 hectare-meters per year) (Shomaker 2006, pp. 43-44). By 2045, 
the City of Alamogordo will likely have a projected deficit of 6,258 
acre-feet per year (772 hectare-meters per year) (more than 2 billion 
gallons per year) (more than 8 billion liters per year) (Shomaker 2006, 
p. 44). Withdrawal and diversion of water from wells located on Forest 
Service and private lands would continue to increase for the 
foreseeable future and compound the effects of the recent and ongoing 
drought, leading to increased degradation of wetland and riparian 
habitat (Forest Service 2008, p. 23), which contain Cirsium wrightii 
localities. In the Sacramento Mountains, C. wrightii occurrences have 
been and will continue to be altered and potentially degraded by the 
issuance of a special use permit to maintain and operate water 
withdrawal from Forest Service lands (Forest Service 2008, p. 26). 
Development of additional water rights will likely dewater C. wrightii 
localities, constituting a threat to the species in this area for the 
foreseeable future.
    Moreover, the Blue Spring and Santa Rosa occurrences of Cirsium 
wrightii are within areas where water is currently drained from 
wetlands or diverted or withdrawn for domestic use, which may 
contribute to degradation and loss of its habitat (Sivinski 1996, p. 5; 
2009; 2009a; NMDGF 2007, pp. 14, 17, 22). Additionally, any activity 
that would interrupt the flow of water from Alamosa Creek has the 
potential to impact C. wrightii. Currently, irrigation and domestic use 
from about 50 farms does not appear to have reduced the baseflow of 
about 9 cfs (0.3 cms) from this spring-fed system (Sierra Soil and 
Water Conservation Service 2008, p. 2). However, Alamosa Creek would 
likely be negatively affected by long-term drought.
    The effects of ongoing and past maintenance and operation of 
existing water diversions can also limit the size of Cirsium wrightii 
populations (Corps 2007, p. 29). For example, the C. wrightii 
population on City of Roswell lands has been extirpated at this 
location since the habitat is no longer suitable for the plant (NMDGF 
2005, pp. 33-34; Sivinski 1996, pp. 4-5; 2006a, p. 5). Loss of springs 
and surface water flow in streams resulting from human use and drought 
have occurred throughout the Roswell Artesian Basin in New Mexico, 
often resulting in diminished discharge from springs or complete loss 
of surface water (Taylor 1983, 1987; NMDGF 2005, 2005a, p. 17; Jones 
and Balleau 1996, pp. 4, 12). Many of these spring systems could have 
harbored populations of C. wrightii; however, it is not possible to 
determine the extent of the loss of C. wrightii populations because 
many springs went dry before surveys could be conducted. Peak annual 
pumping of the alluvial aquifer (a water-bearing deposit of sand and 
gravel) in the Roswell Basin occurred in the 1950s. Since the 1950s, 
administration and metering of groundwater extraction in the basin by 
the New Mexico Office of the State Engineer has resulted in

[[Page 67931]]

stabilization of groundwater levels (NMDGF 2005a, p. 18).
    As artesian wells were developed in the area, discharge from the 
major springs declined proportionately and some of these springs cease 
to flow (Jones and Balleau 1996, p. 4). Surface water flow on BLNWR has 
also been diminished by groundwater pumping, as evidenced by the dead 
springs on Salt Creek and documented reduction in spring flows on the 
refuge (Jones and Balleau 1996; p. 12). Aerial photos which show a 
larger, meandering channel for Bitter Creek are also evidence that 
discharge from Bitter Creek was once greater (Service 2005a; 70 FR 
46312, August 9, 2005). Additionally, BLNWR actively lowers the water 
levels in wetlands during spring and summer (Service 2006, p. 2). It is 
unknown how C. wrightii responds to these changing water levels on the 
refuge, but if soils are not continuously saturated throughout the 
growing season, the species is likely impacted. Information from other 
localities suggests that populations likely contract or habitat may 
become invaded by Phragmites australis as water is withdrawn and parts 
of the occupied wetlands dry (e.g., Sivinski 2005a, pp. 3-4).
    Surface diversions, primarily for irrigation, and groundwater 
pumping for domestic and commercial uses also occurs at the Blue Spring 
locality (NMDGF 2007, p. 22; Lusk 2008). Flow in the Black River is 
sustained by springs, including Rattlesnake and Blue Springs, and is 
generally perennial in the reaches around these springs (NMDGF 2007, p. 
15). Discharge at Blue Spring has varied over the past 100 years: in 
1907, it was recorded at 15.2 cfs (0.430 cms), with a minimum of 14.65 
cfs (0.415 cms) (Bjorklund and Motts 1959, pp. 251, 263); from 1952 to 
1956, discharge varied from 8.5 to 14 cfs (0.24 to 0.40 cms), with a 
mean of 12 cfs (0.34 cms) (Bjorklund and Motts 1959, p. 268); and from 
2002 to 2006, the mean was 11.75 cfs (0.333 cms), with a range from 6.8 
to 23 cfs (0.19 to 0.65 cms) (NMDGF 2007, p.15). Bjorklund and Motts 
(1959, pp. 247, 263) first reported that water levels within the Black 
River Valley (including Blue Spring) decline during the late summer and 
during droughts, mostly from heavy groundwater pumping and lack of 
aquifer recharge. Based on flows recorded in recent years (2000-2006) 
at Blue Springs and in the Black River above the Carlsbad Irrigation 
District diversion, more surface water is appropriated than is 
available in the system (R. Turner, New Mexico Office of the State 
Engineer, pers. comm., April 2007; cited in NMDGF 2007, p. 25). This 
constitutes a significant threat to this locality.
    In summary, the alteration and loss of habitat that currently 
supports C. wrightii, due to groundwater and surface water depletion, 
will continue and likely increase in the foreseeable future. Because 
this species is dependent on water, we find that long-term drought in 
combination with ground and surface water withdrawal is currently a 
significant threat to C. wrightii and its habitat, and will continue to 
be in the foreseeable future.
Climate Change
    The Intergovernmental Panel on Climate Change (IPCC) states that 
warming of the climate system is unequivocal, based on observations of 
increases in global average air and ocean temperatures, widespread 
melting of snow and ice, and rising global average sea level (2007a, p. 
5). For the next two decades, a warming of about 0.4 degrees Fahrenheit 
([deg]F) (0.2 degrees Celsius ([deg]C)) per decade is projected (IPCC 
2007a, p. 12). Temperature projections for the following years 
increasingly depend on specific emission scenarios (IPCC 2007a, p. 13). 
Various emissions scenarios suggest that average global temperatures 
are expected to increase by between 1.1 [deg]F and 7.2 [deg]F (0.6 
[deg]C and 4.0 [deg]C) by the end of the 21st century, with the 
greatest warming expected over land (IPCC 2007a, p. 13). Warming in 
western mountains is projected to cause decreased snowpack, more winter 
flooding, and reduced summer flows, exacerbating competition for over-
allocated water resources (IPCC 2007b, p. 14). The IPCC reports that it 
is very likely that hot extremes, heat waves, and heavy precipitation 
and flooding will increase in frequency (IPCC 2007b, p. 18).
    Based on current understanding of climate change, air temperatures 
are expected to rise and precipitation patterns are expected to change 
in areas occupied by Cirsium wrightii. Because C. wrightii occupies 
relatively small areas of spring or seep habitat in an arid region 
plagued by drought and ongoing aquifer withdrawals (e.g., in the 
Roswell Basin), it may be vulnerable to climatic changes that could 
decrease the availability of water to suitable habitat. For example, 
the most severe drought recorded in New Mexico occurred between 1950 
and 1956. Based on the discharges reported in the Black River (fed by 
Blue Spring, the C. wrightii locality, and other spring sources) from 
1952 to 1956 (daily mean of 15.4 cfs (0.436 cms)) compared to recent 
discharges (2002 to 2006, daily mean of 10.1 cfs (0.286 cms)), flows in 
the Black River are currently lower than during the drought of the 
1950s (NMDGF 2007, p. 31). Moreover, Sivinski (2005a, pp. 3-4) reports 
that springs and wet valleys have been affected by drought in at least 
three canyons of the Sacramento Mountains, New Mexico, resulting in 
reduced C. wrightii populations. Similar water loss may occur within 
other C. wrightii localities, as analyzed above. If climate change 
leads to future drought, additional dewatering and reduction of C. 
wrightii habitat may occur.
    Although the information available on climate change indicates that 
New Mexico will be impacted (New Mexico Climate Change Advisory Group 
2006, p. 1), there is no information specific to the effects of climate 
change on Cirsium wrightii or its habitat. Reliable predictive models 
have not been developed for use at the local scale (i.e., the eight 
occupied localities), and there is little certainty regarding the 
timing and magnitude of the resulting impacts. For example, the 
vulnerability of C. wrightii habitats to a drying climate depends, in 
large part, on the sources of their water supply. The sources of water 
to C. wrightii habitats are precipitation, surface water, and 
groundwater. Habitats that are sustained mainly by precipitation are 
the most likely to be affected in a drying climate. Alternatively, 
localities that are supplied primarily by groundwater will likely have 
the greatest resistance to climate change due to water stored in 
aquifers (e.g., see Poff et al. 2002, pp. 18-19). However, based on 
projections made by the IPCC, we consider climate change to be a 
potential exacerbating factor, worsening the impacts of other known 
threats. These threats include habitat degradation from prolonged 
periods of drought and increased temperature, and the allocation of 
water for use by the human population and agriculture as well as a 
number of potential confounding effects. In summary, we do not have 
evidence indicating that climate change is currently a factor affecting 
C. wrightii's existence, because the information available on the 
subject is insufficiently specific to the species or the possible 
current or future effects of climate change on the sources of their 
water supply. However, we consider climate change to be a potential 
exacerbating factor and will continue to evaluate new information on 
the subject as it becomes available.
Introduced Plants
    Introduced plants increase the potential for habitat loss due to 
wildfire and competition with Cirsium wrightii.

[[Page 67932]]

Phragmites australis has recently invaded half of the known C. wrightii 
localities (BLNWR, Tularosa Creek, Santa Rosa, and Karr Canyon), 
forming dense stands in areas and increasing fuel load and threat of 
wildfire. Standing dead canes of P. australis and associated litter 
often constitute twice as much biomass as living shoots (Forest Service 
2010). The high productivity and density of P. australis stands provide 
fuel loads that are often high. This abundant dead fuel carries fire 
well, allowing stands to burn even when the current year's shoots are 
green (Forest Service 2010).
    As an example, on March 5, 2000, the Sandhill fire burned 1,000 ac 
(405 ha) of the western portion of the BLNWR, including portions of 
Bitter Creek. The fire burned through Dragonfly Spring, eliminating the 
vegetation shading the spring. Although Cirsium wrightii does not occur 
immediately within the burned area, the changes to wetland vegetation 
exemplify how its habitat might respond following wildfire. The pre-
fire dominant vegetation of submerged aquatic plants and mixed native 
grasses within the burned area has been replaced by the invasive 
Phragmites australis (NMDGF 2005, p. 19-21). The P. australis present 
at BLNWR is likely of European origin (Service 2006, p. 5). Prior to 
the wildfire, small patches of P. australis occurred throughout Bitter 
Creek, whereas post-fire, P. australis colonized the burned area to 
form a continuous dense stand (NMDGF 2005, pp. 19-21). Stands of P. 
australis have also recently become a dominant plant in other C. 
wrightii localities (Sivinski 2005a, pp. 3-4; Sivinski and Bleakly 
2004, p. 5). Controlled burns have been implemented on BLNWR to burn 
grass, sedge, cattail, and nonnative vegetation (e.g., Salsola spp. 
(Russian thistle and tumbleweed)), in an attempt to reduce the risk of 
large uncontrolled wildfires by removing excessive amounts of Salsola 
spp. and P. australis (Service 2006). This may temporarily reduce the 
threat of wildfire in one area of BLNWR, but repeated prescribed burns 
are likely needed to continually suppress P. australis growth (Service 
2006, pp. 4-5).
    No measures are being implemented in the other localities to reduce 
P. australis. Moreover, temperatures from prescribed burns are rarely 
high enough to be lethal to P. australis or to penetrate deeply into 
the wet or moist soils common in their habitat (Forest Service 2010 and 
references therein). Prescribed fire burns above-ground parts of P. 
australis, but below-ground rhizomes usually survive and produce plants 
later in the growing season or in subsequent years (Forest Service 2010 
and references therein). Rarely is P. australis abundance decreased by 
fire, and postfire recovery is typically rapid. As such, prescribed 
fire likely will do little to reduce the long-term threat of P. 
australis to C. wrightii.
    In addition to increasing the potential for wildfire, Phragmites 
australis can also quickly invade a site and take over a wetland, 
crowding out native plants and changing hydrology (Plant Conservation 
Alliance 2005, p. 1). The dense plant growth blocks sunlight to other 
plants growing in the immediate area and occupies all available 
habitat, turning many wetlands into dense stands that support only P. 
australis (Plant Conservation Alliance 2005, p. 1). Two Cirsium 
wrightii localities have recently been either extirpated (an occurrence 
in Karr Canyon), or significantly reduced in size (Tularosa Creek), 
following an expansion of P. australis (Sivinski 1996, p. 2, 2005a, p. 
4; 2009a, p. 2). P. australis is a current threat and will likely be a 
continuing threat for C. wrightii localities through increased fire 
risk, competition, and changes in hydrology, especially when habitat is 
disturbed through burning or drying.
Ungulate Grazing
    Grazing likely impacts some localities of Cirsium wrightii, but 
does not appear to be a widespread threat to the species. It is 
estimated that livestock grazing has damaged approximately 80 percent 
of stream and riparian ecosystems in the western United States (Belsky 
et al. 1999, p. 419). The damage occurs from increased sedimentation, 
decreased water quality, and trampling and overgrazing of stream banks 
where succulent forage exists (Armour et al. 1994, p. 10; Belsky et al. 
1999, p. 419; Fleischner 1994, p. 631). Moreover, many acres of marsh 
habitats at Santa Rosa have also been plowed and converted to Festuca 
pratensis (meadow fescue) pasture for livestock grazing (Service 2005, 
p. 10; Corps 2007, p. 25). In the semi-arid southwestern United States, 
wet marshes and other habitat of C. wrightii attract ungulates because 
of the availability of water and high-quality forage (e.g., see 
Hendrickson and Minckley 1984, p. 134). Similar to C. vinaceum, dry 
periods likely increase the effects of livestock trampling and 
herbivory on C. wrightii when other water and forage plants are not 
available (75 FR 30761, June 2, 2010). Grazing may be more concentrated 
within habitats similar to those occupied by C. wrightii during drought 
years, when livestock are prone to congregate in wetland habitats or 
where forage production is greater than in adjacent dry uplands (e.g., 
see Forest Service 2003). Although no studies specifically related to 
the effects of livestock grazing on C. wrightii have been conducted 
(NMRPTC 2009, p. 2), livestock will likely eat C. wrightii when other 
green forage is scarce, and when the seedlings or rosettes are 
developing and abundant.
    The localities in the Sacramento Mountains, Santa Rosa, Alamosa 
Springs, and Blue Spring have the potential to be subjected to 
trampling and herbivory (75 FR 30762; NMDGF 2000, p. 2, 2004, p. 7, 
2005, p. 47; Corps 2007, p. 25; Service 1994, p. 6, 2005c, p. 2). For 
example, about three quarters of C. wrightii were grazed at one 
locality near Santa Rosa (Corps 2007, p. 25). Additionally, much of the 
private wet meadows and marsh habitats in the Santa Rosa area have been 
severely degraded by livestock grazing for many years (Sivinski and 
Bleakly 2004). Except for Blue Hole Cienaga, we are not aware of any 
fences enclosing these localities that would limit impacts to the 
species. In the Sacramento Mountains, for example, springs and marshes 
provide a majority of the watering sites for both livestock and 
wildlife species, especially elk (75 FR 30762). These wet springs and 
marshes are subject to trampling and hoof damage, and receive 
especially heavy use during drought periods, when neither water nor 
green forage are readily available elsewhere. Trampling could easily 
result in damage to seedlings, rosettes, and flowering stalks, thereby 
preventing reproduction by affected plants. It is possible that elk and 
livestock grazing within and adjacent to spring ecosystems could alter 
or remove habitat or limit the distribution of Cirsium wrightii; 
however, we found little information to support this possibility. 
Still, we believe the observations of livestock and elk herbivory and 
trampling that directly affect C. vinaceum and its habitat likely are 
also occurring in some of the C. wrightii localities; however, it is 
unknown whether these are localized or widespread threats to the 
species.
    In summary, while livestock activities do not appear to be a 
widespread threat at the current time, localized impacts have been 
observed, and increased use of wet springs and marshes during drought 
conditions constitutes a threat in the foreseeable future. We will 
continue to monitor livestock grazing and trampling to determine 
whether C. wrightii is threatened.
Wetland Filling and Development
    As described below, wetland filling and development has impacted 
the

[[Page 67933]]

Santa Rosa locality, but does not appear to be a threat to the species. 
A substantial percentage of wetlands in the Santa Rosa area have 
disappeared in the last 50 to 80 years (Metric Corporation et al. 2002, 
p. 5). Springs that fed suitable habitat for Helianthus paradoxus and 
likely also contained Cirsium wrightii have been converted to swimming 
pools and fishing ponds or drained and filled for sports fields in the 
towns of Roswell and Santa Rosa, New Mexico (e.g., see Sivinski and 
Bleakly 2004, p. 1; Service 2005, p. 8). Moreover, some springs and 
associated wetlands where C. wrightii occurred have been drained and 
developed, and the potential for further development exists (Metric 
Corporation 2001; Metric Corporation et al. 2002; Sivinski 2009a, p. 1; 
Sivinski and Bleakly 2004, p. 1; Service 2008b, p. 42).
    Some of the Cirsium wrightii occurrences within the Santa Rosa 
locality continue to be impacted through filling and development and 
regular mowing. C. wrightii occurs at the Blue Hole fish hatchery ponds 
that are owned by the City of Santa Rosa (Sivinski 1996, p. 4). The 
City of Santa Rosa plans to dredge and fill these ponds for municipal 
use in the foreseeable future (Service 2008b, p. 42), which would 
undoubtedly impact the species. A similar action occurred in 2001 when 
the C. wrightii population at Power Dam Municipal Park in Santa Rosa 
was extirpated when the reservoir was drained (Sivinski 2005a, p. 3; 
2009a, p. 1). Numerous wetlands in Santa Rosa were also lost many years 
ago to an impoundment, in which 17 ponds were created and used for a 
fish hatchery. The fish hatchery has since been abandoned, and all but 
four of the ponds filled. The remaining adjacent 116 ac (47 ha) of the 
Blue Hole Cienaga were purchased by the State of New Mexico to protect 
habitat that includes the Federally threatened Helianthus paradoxus, C. 
wrightii, and the State-endangered Spiranthes magnicamporum (Great 
Plains lady's tresses) (New Mexico State Forestry 2008, p. 1). Although 
we are not aware of any other specific residential or commercial 
development plans at this or other localities, actions that drain or 
fill wetlands or other habitat occupied by the species would impact C. 
wrightii.
Summary of Factor A
    In summary, we found that past and present alteration of rare 
desert springs, seeps, and wetland habitats that support Cirsium 
wrightii is a significant threat. The four largest localities of C. 
wrightii at Blue Spring, BLNWR, Santa Rosa, and Alamosa Creek have the 
potential to be further modified by ongoing and future water 
withdrawal. Changes in water tables throughout the range of C. wrightii 
have also resulted in diminished discharge from springs or complete 
loss of surface water. Therefore, there has been a trend of diminishing 
habitat quantity and excessive degradation of habitat quality for the 
species throughout its range, as a result of agriculture and urban 
development, diversion of springs, and drought. Moreover, the presence 
of and effects from Phragmites australis threatens C. wrightii 
localities through increased fire risk, competition, and changes in 
hydrology. On the basis of the information presented above, we find 
that Cirsium wrightii may be threatened by the present or threatened 
destruction, modification, or curtailment of its habitat, both now and 
in the foreseeable future.

B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    We do not have any evidence of risks to Cirsium wrightii from 
overutilization for commercial, recreational, scientific, or 
educational purposes, and we have no reason to believe this factor will 
become a threat to the species in the future. Therefore, we find 
overutilization for commercial, recreational, scientific, or 
educational purposes does not threaten C. wrightii now or in the 
foreseeable future.

C. Disease or Predation

Disease
    Cirsium wrightii is not known to be affected or threatened by any 
disease. Therefore, we find that disease does not threaten C. wrightii 
now or in the foreseeable future.
Insect Predation
    Native and nonnative insect populations have the potential to 
impact the condition, reproduction, and distribution of Cirsium 
wrightii. Observed seed predators on the similar C. vinaceum in the 
Sacramento Mountains include Paracantha gentilis, a native specialist 
gall fly; Platyptilia carduidactyla, the native artichoke plume moth; 
Euphoria inda, a native generalist bumble flower beetle; Rhinocyllus 
conicus, an introduced seed-head weevil; and Trichosirocalus horridus, 
an introduced rosette weevil (Sivinski 2008, pp. 1-11; Gardner 2010, 
pp. 2-3). There have been intentional releases of Rhinocyllus conicus 
to control Carduus nutans (musk thistle) (Sivinski 1994, p. 2; 2007, p. 
6; NMRPTC 2009, p. 2; Bridge 2001, p. 1; AGFD 2001, p. 2). This exotic 
weevil has recently been found in habitat occupied by C. wrightii, C. 
vinaceum, and the exotic Carduus nutans at the Silver Springs locality 
(Sivinski 2007, p. 6; Gardner and Thompson 2008, p. 4). It is not known 
where Trichosirocalus horridus came from or whether they were 
intentionally released (Gardner 2010, p. 3); however, this exotic 
rosette weevil is also present in Carduus nutans populations ranging 
from the northern extent of the Mescalero Apache reservation south to 
Agua Chiquita canyon in the Sacramento Mountains.
    Rhinocyllus conicus is not host specific to Carduus species and has 
been found living on 22 of the North American Cirsium species (Louda et 
al. 2003). This weevil is available from commercial suppliers and is 
easily gathered and transported from established colonies. Breeding and 
egg placement by R. conicus begins in mid-June, peaks in early July, 
and continues into August (Sivinski 2008, p. 5). Newly hatched larvae 
bury into the flower head and feed on the tissue. Most R. conicus at 
the Silver Springs locality emerge from the flower heads by early 
September; however, some immature larvae were still present in the 
flower heads of C. vinaceum in September (Sivinski 2008, p. 5). Flower 
heads of C. wrightii grow during late July to early August, which 
overlaps with developing and feeding larvae of R. conicus. The 
establishment of R. conicus beyond the Silver Springs locality will 
likely occur in the near future because stands of C. nutans are common 
in many of the drainages throughout the Sacramento Mountains (Gardner 
and Thompson 2008, p. 4), and we are concerned that it may spread to C. 
wrightii populations. For these reasons, we intend to monitor 
localities in the Sacramento Mountains to determine whether C. wrightii 
could be a potential host and possibly threatened by R. conicus 
infestations.
    Trichosirocalus horridus, feeds on Carduus nutans during the 
rosette stage, killing first-year rosettes and stopping the growth of 
older plants. This weevil is available from commercial suppliers or can 
be gathered and transported from established colonies (Flanders et al. 
2001, p. 4; Jennings et al. 2010, pp. 4-5). Moreover, T. horridus is 
capable of spreading at least a mile (1.61 km) per year on their own 
(Flanders et al. 2001, p. 4). Adults emerge from summer resting places 
in the fall. They lay eggs in the midrib of thistle leaves, and 
complete egg-laying in the spring. After 10 to 12 days, the eggs hatch, 
and the young weevils tunnel from the midrib into the rosette, feeding 
and causing

[[Page 67934]]

damage or possibly killing the crown tissue. The new adults emerge in 
May and June, feed briefly, and pass the summer in a period of 
inactivity (Flanders et al. 2001, p. 3). We are concerned about 
potential effects to C. wrightii and intend to monitor C. wrightii 
localities to determine if this introduced rosette weevil threatens the 
species.
    Rhinocyllus conicus and a native predator, the stem borer weevil 
(Lixus pervestitus), caused a widespread premature stem death to the 
flower heads of the Silver Springs population of the endangered C. 
vinaceum, which co-occurs with C. wrightii (Sivinski 2007, pp. 8-12). 
These 2 insects collectively damaged up to 99 percent of C. vinaceum 
within the Silv