Endangered and Threatened Wildlife and Plants:


[Federal Register: January 10, 2008 (Volume 73, Number 7)]

[Proposed Rules]

[Page 1855-1861]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]


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Fish and Wildlife Service

50 CFR Part 17

[FWS-R8-ES-2007-0023; 1111 FY07 MO; ABC Code B2]

Endangered and Threatened Wildlife and Plants; 90-Day Finding on Petition To List the Amargosa River Population of the Mojave Fringe- Toed Lizard (Uma scoparia) as Threatened or Endangered With Critical Habitat

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 90-day petition finding and initiation of status review.

SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 90-day finding on a petition to list the Amargosa River population of the Mojave fringe-toed lizard (Uma scoparia) in the State of California as threatened or endangered under the Endangered Species Act of 1973, as amended (Act). We find that the petition presents substantial scientific or commercial information indicating that listing this population may be warranted. Therefore, with the publication of this notice, we are initiating a status review of the Amargosa River population of the Mojave fringe-toed lizard, and we will issue a 12- month finding on our determination as to if the petitioned action is warranted. To ensure that the status review of the Amargosa River population of the Mojave fringe-toed lizard is comprehensive, we are soliciting scientific and commercial data regarding this species. We will make a determination on critical habitat for this species if, and when, we initiate a listing action.

DATES: We made the finding announced in this document on January 10, 2008. To be considered in the 12-month finding for this petition, comments and information must reach us by March 10, 2008.

ADDRESSES: You may submit comments by one of the following methods:

Federal eRulemaking Portal: http://www.regulations.gov.

Follow the instructions for submitting comments.

U.S. mail or hand-delivery: Public Comments Processing, Attn: RIN 1018-AV02; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, Suite 222; Arlington, VA 22203.

We will not accept e-mail or faxes. 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 Information Solicited section below for more information).

FOR FURTHER INFORMATION CONTACT: Diane Noda, Field Supervisor, Ventura Fish and Wildlife Office, U.S. Fish and Wildlife Service, 2493 Portola Road, Suite B, Ventura, CA 93003; telephone 805-644-1766 ext. 319; facsimile 805-644-3958. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800-877-8339.


Public Information Solicited

When we make a finding that a petition presents substantial information to indicate that listing a species may be warranted, we are required to promptly commence a review of the status of the species. To ensure that the status review is complete and based on the best available scientific and commercial information, we are soliciting information concerning the status of the Amargosa River population of the Mojave fringe-toed lizard. We are seeking information regarding the species' historical and current status and distribution, its biology and ecology, ongoing conservation measures for the species and its habitat, and threats to the species and its habitat. We request any additional information, comments, and suggestions from the public, other concerned governmental agencies, Native American tribes, the scientific community, industry, or any other interested parties.

Please note that comments merely stating support 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 shall be made ``solely on the basis of the best scientific and commercial data available.'' At the conclusion of the status review, we will issue the 12-month finding on the petition, as provided in section 4(b)(3)(B) of the Act (16 U.S.C. 1533 (b)(3)(B)).

If we determine that listing the Amargosa River population of the Mojave fringe-toed lizard is warranted, it is our intent to propose critical habitat to the maximum extent prudent and determinable at the time we propose to list the species. Therefore, with regard to areas within the geographical area currently occupied by the species, we also request data and information on what may constitute physical or biological features essential to the conservation of the species, where these features are currently found, and whether any of these features may require special management considerations or protection. In addition, we request data and information regarding whether there are areas outside of the geographical area occupied by the species that are essential to the conservation of the species. Please provide specific comments and information, as to what, if any, critical habitat you think we should propose for designation if the species is proposed for listing, and why such habitat meets the requirements of the Act.

You may submit your comments and materials concerning this finding by one of the methods listed in the ADDRESSES section. We will not accept comments you send by e-mail or fax. Please note that we may not consider comments we receive after the date specified in the DATES section in our final determination.

Before including your address, phone number, e-mail address, or other personal identifying information in your comment, you should be aware that we will post your entire comment--including your personal identifying information--on http://www.regulations.gov. While you can

ask us in your comment to withhold your personal identifying information from public review, we cannot guarantee that we will be able to do so.


Section 4(b)(3)(A) of the Act requires that we make a finding on whether a petition to list, delist, or reclassify a species presents substantial scientific or commercial information indicating that the petitioned action may be warranted. Such findings are based on information contained in the petition, supporting information submitted with the petition, and information otherwise readily available in our files at the time we make the determination. To the maximum extent practicable, we are to make this finding within 90 days of our receipt of the petition, and publish our notice of the finding promptly in the Federal Register.

Our standard for substantial scientific or commercial information, as defined by the Code of Federal Regulations (CFR), with regards to a 90-day petition finding is ``that amount of information that would lead a reasonable person to believe that the measure proposed in the petition may be warranted'' (50 CFR 424.14(b)). If we find that the petition

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presents substantial scientific or commercial information, we are required to promptly commence a status review of the species.

We received a petition dated April 10, 2006, from the Center for Biological Diversity and Ms. Sylvia Papadakos-Morafka requesting that the Mojave fringe-toed lizard (Uma scoparia) occurring in the Amargosa River area of San Bernardino County, California, be listed as a threatened or endangered distinct population segment (DPS) under the Act. Additionally, the petition requested that critical habitat be designated concurrent with listing. The petition clearly identified itself as such and included the identification information for the petitioners, as required in 50 CFR 424.14(a). In response to the petitioners' request, we sent a letter to the petitioners dated June 21, 2006, explaining that we would not be able to address their petition at that time. The reason for this delay was that responding to existing court orders and settlement agreements for other listing actions required nearly all of our listing funding. We also concluded in our June 21, 2006, letter that emergency listing of the Amargosa River population of the Mojave fringe-toed lizard was not indicated. Delays in responding to the petition continued due to the high priority of responding to court orders and settlement agreements, until funding recently became available to respond to this petition.

In making this finding, we based our decision on information provided by the petitioners that we determined to be reliable after reviewing sources referenced in the petition, as well as information readily available in our files at the time of the petition review. We evaluated the information in accordance with 50 CFR 424.14(b). Our process for making this 90-day finding under section 4(b)(3)(A) of the Act and Sec. 424.14(b) of our regulations is limited to a determination of whether the information in the petition meets the ``substantial scientific and commercial information'' threshold (as mentioned above).

Species Information

The Mojave fringe-toed lizard (Uma scoparia) is in the family Phrynosomatidae, the family of the North American spiny lizards. Fringe-toed lizards are medium-sized lizards and seem to be completely restricted to a sand-dwelling existence (Norris 1958, p. 253). The Mojave fringe-toed lizard may reach a snout to vent length of 4.5 inches (112 millimeters), with a dorsoventrally (top to bottom) compressed body and tail (Hollingsworth et al. 1999, p. 1). The Mojave fringe-toed lizard has smooth skin and a fine pattern of small black circles and flecks. Both sides of the belly have a conspicuous black spot, and the underside of the tail has black bars. The Mojave fringe- toed lizard is distinguished from other fringe-toed lizards by the dark black spot on each side of the belly and the crescent-shaped markings present on the sides of the throat.

The concealing coloration of fringe-toed lizards is striking, being one of the best examples of this phenomenon among North American vertebrates. Adults of the species have a yellow-green wash on the belly and pink on the sides during breeding periods, but during other times of year, the Mojave fringe-toed lizard's color mimics the sand dunes on which they dwell (Norris 1958, p. 253).

The Mojave fringe-toed lizard is omnivorous throughout its life. They primarily feed on insects, but will also eat seeds and flowers (Stebbins 1944, p. 329). Annual plant species provide important forage during the springtime, though the reliance on vegetative plant species may diminish during the summer with increased arthropod availability (Stebbins 1944, p. 329). The Mojave fringe-toed lizard derives most of its water from arthropod and plant food.

The Mojave fringe-toed lizard generally reaches sexual maturity during the second summer following hatching. Reproductive activity in both sexes is annually variable, in accordance with seasonal rainfall patterns (Mayhew 1966, pp. 119-120). Breeding colors and testis size indicate the male breeding period, which occurs between April and late June. Female breeding colors are displayed between April and September, with maximized colors during May through July (Mayhew 1966, pp. 115- 117). Ovarian egg counts also fluctuate in response to rainfall and food availability; reduced egg counts and fewer juveniles were observed following dry winters. There is also evidence to suggest that female lizards may have more than one brood per year (Mayhew 1966, p. 118).

Fringe-toed lizards likely select unstabilized areas with intermediate grain sand because it eases self-burying and facilitates respiration (Pough 1970, p. 154). Self-burial by the fringe-toed lizard is presumed to be defensive, as there is no evidence to suggest that it is thermoregulatory or used for subsurface hunting as exhibited by other genera of sand lizards (Pough 1970, p.153). Fringe-toed lizards are highly dependent on desert vegetation as a source of cover, for thermoregulation and as habitat for primary prey (Pough 1970, pp. 152- 153). Mojave fringe-toed lizards spend their inactive periods and hibernation cycle (November to February) beneath the sand (Mayhew 1966, pp. 120-121). It is believed that their flattened body form, skin surface scales, and wedge-shaped head with well-developed eye and ear flaps are all useful for the burrowing behavior exhibited by this genus (Pough 1970, p. 145).

The Mojave fringe-toed lizard is endemic to the deserts of southern California and a small area of western Arizona. The Mojave fringe-toed lizard occurs in the lower Sonoran life zones of the Mojave Desert and the northwestern reaches of the Sonoran Desert. Fringe-toed lizard distribution is discontinuous throughout the range since the animals are restricted to deposits of fine, loose sand (Stebbins 1944, p. 313). The Amargosa River population of the Mojave fringe-toed lizard consists of individuals occurring at Dumont Dunes, Ibex Dunes, and Coyote Holes (Murphy et al. 2006, pp. 239-241). Dumont Dunes' main dune area is approximately 9,600 acres (ac) (3,885 hectares (ha)). Dumont Dunes began to form approximately 18,000 years ago when Lake Manley in Death Valley and Lake Dumont in the Silurian Valley began to dry, leaving behind sand to be blown and deposited forming the dunes. Ibex Dunes is about 1,700 ac (688 ha) and is the northern limit for the Amargosa River population of the Mojave fringe-toed lizard. Coyote Holes is a 50-ac (20-ha) sand blow-out located approximately 12 miles (mi) (20 kilometers (km)) southeast of the eastern end of Dumont Dunes. The nearest population of Mojave fringe-toed lizards is known from Silver Lake located approximately 20 mi (32 km) southeast of Dumont Dunes.

Dispersal of Mojave fringe-toed lizards between populations is poorly studied, but based on observed movements and limited ability of the species to cross unsuitable habitat, it is unlikely that isolated populations interact. No specimen of Uma has been captured more than a very short distance 148 feet (ft) (45 meters (m)) from wind-blown sand deposits (Norris 1958, p. 257). Population status and relative density data for the Mojave fringe-toed lizard is not currently available. To estimate the amount of habitat rangewide for the Mojave fringe-toed lizard, we used distribution data from Murphy et al. (2006, p. 230), Hollingsworth et al. (1999, p. 1), and Norris (1958, pp. 265-266) to develop maps showing the amount of potential

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Mojave fringe-toed lizard habitat. Based on our habitat analysis, the Amargosa population of the Mojave fringe-toed lizard comprises approximately 3 to 5 percent of the species' range.

Distinct Population Segment

We consider a species for listing under the Act if available information indicates such an action might be warranted. ``Species'' is defined in section 3 of the Act to include any subspecies of fish or wildlife or plants, and any distinct vertebrate population segment of fish or wildlife that interbreeds when mature (16 U.S.C. 1532 (16)). We, along with the National Marine Fisheries Service (now the National Oceanic and Atmospheric Administration--Fisheries), developed the Policy Regarding the Recognition of Distinct Vertebrate Population Segments (DPS Policy) (February 7, 1996; 61 FR 4722) to help us in determining what constitutes a DPS. The policy identifies three elements that we are to consider in making a DPS determination. These elements include: (1) The discreteness of the population segment in relation to the remainder of the species to which it belongs; (2) the significance of the population segment to the species to which it belongs; and (3) the population segment's conservation status in relation to the Act's standards for listing. If we determine that a population segment meets the discreteness and significance standards, then the level of threat to that population segment is evaluated based on the five listing factors established by the Act to determine whether listing the DPS as either threatened or endangered is warranted.


Citing the Services' DPS policy (61 FR 4722), the April 2006 petition asserts that the Amargosa River population of the Mojave fringe-toed lizard qualifies as a DPS based on discreteness. The DPS policy states that a population may be considered discrete if it satisfies either one of the following conditions:

(1) It is markedly separated from other populations of the same taxon as a consequence of physical, physiological, ecological, or behavioral factors. Quantitative measures of genetic or morphological discontinuity may provide evidence of this separation.

(2) It is delimited by international governmental boundaries within which differences in control of exploitation, management of habitat, conservation status or regulatory mechanisms exist that are significant in light of section 4(a)(1)(D) of the Act.

The petitioners assert that the Amargosa River population of Mojave fringe-toed lizards is restricted to dunes with fine, loose sand. The petitioners also assert that the Amargosa River population of Mojave fringe-toed lizards of Coyote Holes and Dumont and Ibex Dunes are isolated and discrete from other dunes and other populations by the presence of intervening, unsuitable habitat, due to the fact that Mojave fringe-toed lizards are not known to disperse across long distances of unsuitable habitat (Norris 1958, p. 257).

The petitioners provided the following quote from Murphy et al. (2006, p. 241) to support their assertion that the Amargosa River population of the Mojave fringe-toed lizard is discrete: ``Natural geographic barriers, including the absence of sand and presence of mountains, separate populations from one another. Each Dune is a discrete entity and it is extremely unlikely that gene flow is occurring among the isolated dunes, and especially among dune systems not connected by a recent hydrogeologic system. Ecologically, dispersal is virtually impossible because of the absence of intervening sand dunes.'' The petitioners assert that Dumont Dunes, Ibex Dunes, and Coyote Holes are thus isolated from other suitable habitat, making dispersal highly improbable. The petitioners also assert that the physical isolation of the Amargosa River population of the Mojave fringe-toed lizard further indicates genetic differences between this population and others of the species. The April 2006 petition cites the genetic work of Murphy et al. (2006, pp. 231-238), which determined that the Amargosa River population of the Mojave fringe-toed lizard contains unique haplotypes [The petitioners are referring to differences in mitochondrial DNA sequenced from maternal haplotypes. A haplotype is a set of closely linked genetic markers present on one chromosome, which tend to be inherited together.] not found elsewhere within the range of the species.

The Services' DPS policy requires that only one of the discreteness criteria be satisfied in order for a population of a vertebrate species to beconsidered discrete. After reviewing the information provided (e.g., Murphy et al. 2006, pp. 226-247) in the petition and in our files, we believe that the Amargosa River population may be physically isolated from other populations and may also be genetically distinct from other populations. We based this on a preliminary review of maps of the Mojave Desert in our files, the position of the three dune locations, the petitioners' information on the Amargosa River population, and the research of Murphy et al. (2006, pp. 242-247) cited in the petition on dunes occupied by Mojave fringe-toed lizards and the genetics of this species. From our review of this information, we find that there is substantial information indicating the Amargosa River population of the Mojave fringe-toed lizard may satisfy the discreteness element of the DPS policy.


If we determine that a population meets the DPS discreteness element, we then consider if it also meets the DPS significance element. The DPS policy (61 FR 4722) states that if a population segment is considered discrete under one or more of the discreteness criteria, its biological and ecological significance will be considered in light of Congressional guidance that the authority to list DPSs be used ``sparingly'' while encouraging the conservation of genetic diversity. In making this determination, we consider available scientific evidence of the discrete population's importance to the taxon to which it belongs. Since precise circumstances are likely to vary considerably from case to case, the DPS policy does not describe all the classes of information that might be used in determining the biological and ecological importance of a discrete population. However, the DPS policy does provide four possible reasons why a discrete population may be significant. As specified in the DPS policy (61 FR 4722), this consideration of the significance may include, but is not limited to, the following:

(1) Persistence of the discrete population segment in an ecological setting unusual or unique to the taxon;

(2) Evidence that loss of the discrete population segment would result in a significant gap in the range of a taxon;

(3) Evidence that the discrete population segment represents the only surviving natural occurrence of a taxon that may be more abundant elsewhere as an introduced population outside its historic range; or

(4) Evidence that the discrete population segment differs markedly from other populations of the species in its genetic characteristics.

The April 2006 petition asserts that the Amargosa River population of the Mojave fringe-toed lizard, being discrete from other populations, also meets the significance element of the DPS policy for three of the four reasons above: (1) Persistence in an ecological setting unusual or unique to the taxon; (2) loss of the population would create a significant gap in the range of a taxon; and (3) the population differs markedly

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from other populations in its genetic characteristics.

The April 2006 petition asserts that the loss of the Amargosa River population of the Mojave fringe-toed lizard would result in the species disappearing from a unique ecological setting. The petitioners state that populations at Coyote Holes, Ibex Dunes, and Dumont Dunes represent the northernmost extension of the species' range and are the only populations in the Amargosa River drainage. The petitioners also assert that the loss of the Amargosa River population would result in a significant gap in the range of the Mojave fringe-toed lizard. The petition further asserts that the Amargosa River population of the Mojave fringe-toed lizard differs markedly from other Mojave fringe- toed lizard populations in genetic characteristics. These populations contain unique haplotypes that very likely represent adaptation to unique regional characteristics, such as differences in climate, vegetation, and substrate. The petition cites the research of Murphy et al. (2006, pp. 236-238), which identified the Amargosa River population of the Mojave fringe-toed lizard as one of two distinct maternal lineages that have been isolated since likely the mid-Pleistocene (about 500,000 years ago). The Amargosa River population was found to have the greatest amount of DNA sequence divergence (Murphy et al. 2006, p. 232). This lineage includes individuals from Coyote Holes and Ibex and Dumont Dunes, which are closely related and likely had recent contact during more mesic (moderately moist) periods of the late Pleistocene and Holocene (i.e.,