[Federal Register: February 2, 2005 (Volume 70, Number 21)]
[Proposed Rules]               
[Page 5401-5404]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife and Plants; 90-Day Finding on 
a Petition To List the Gentry Indigo Bush as Endangered

AGENCY: Fish and Wildlife Service, Interior.

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


SUMMARY: We, the U.S. Fish and Wildlife Service (FWS), announce a 90-
day administrative finding on a petition to list the Gentry indigo bush 
(Dalea tentaculoides) under the Endangered Species Act of 1973, as 
amended (Act). We find that the petition presents substantial 
information indicating that listing the Gentry indigo bush may be 
warranted. Therefore, we are initiating a status review to determine if 
listing the species is warranted. To ensure that the review is 
comprehensive, we are soliciting information and data regarding this 

DATES: The administrative finding announced in this document was made 
on January 25, 2005. To be considered in the 12-month finding for this 
petition, comments and information should be submitted to us by April 
4, 2005.

ADDRESSES: Data, information, comments, or questions concerning this 
petition and our finding should be submitted to the Field Supervisor, 
Arizona Ecological Services Office, 2321 West Royal Palm Road, Suite 
103, Phoenix, Arizona 85021-4951. The petition, administrative finding, 
supporting data, and comments will be available for public inspection, 
by appointment, during normal business hours at the above address.

FOR FURTHER INFORMATION CONTACT: Mima Falk, Plant Ecologist, at the 
Tucson Sub-Office, 201 North Bonita Ave, Suite 141, Tucson, Arizona, 
85745, or at 520-670-6150 x 225.



    Section 4(b)(3)(A) of the Endangered Species Act of 1973, as 
amended (16 U.S.C. 1531 et seq.) (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. We are to base this finding on all 
information available to us at the time we make the finding. 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 this finding 
promptly in the Federal Register.
    Our standard for substantial information within the Code of Federal 
Regulations (CFR) with regard 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 substantial information was presented, we 
are required to promptly commence a review of the status of the 
species, if one has not already been initiated, under our internal 
candidate assessment process.
    In making this finding, we relied on information provided by the 
petitioners and evaluated that information in accordance with 50 CFR 
424.14(b). This finding summarizes information included in the petition 
and information available to us at the time of the petition review. Our 
process of coming to a 90-day finding under section 4(b)(3)(A) of the 
Act and section 424.14(b) of our regulations is limited to a 
determination of whether the information in the petition meets the 
``substantial information'' threshold.
    We do not conduct additional research at this point, nor do we 
subject the petition to rigorous critical review. Rather, as the Act 
and regulations contemplate, in coming to a 90-day finding, we accept 
the petitioner's sources and characterizations of the information 
unless we have specific information to the contrary.
    Our finding considers whether the petition states a reasonable case 
for listing on its face. Thus, our finding expresses no view as to the 
ultimate issue of whether the species should be listed. We reach a 
conclusion on that issue only after a more thorough review of the 
species' status. In that review, which will take approximately 9 more 
months, we will perform a rigorous, critical analysis of the best 
available scientific and commercial information, not just the 
information in the petition. We will ensure that the data used to make 
our determination as to the status of the species is consistent with 
the Act and Information Quality Act.
    On January 7, 2002, we received a petition dated January 2, 2002, 
requesting that we list the Gentry indigo bush (Dalea tentaculoides) as 
an endangered species, and that critical habitat be designated 
concurrently with the listing. The petition, submitted by the Center 
for Biological Diversity (Center), was clearly identified as a petition 
for a listing rule, and contained the names, signatures, and addresses 
of the requesting parties. Included in the petition was supporting 
information regarding the species' taxonomy and ecology, historical and 
current distribution, present status, and potential causes of decline. 
We acknowledged the receipt of the petition in a letter to Mr. Noah 
Greenwald, dated April 25, 2002. In that letter, we also advised the 
petitioners that due to funding constraints in fiscal year (FY) 2002, 
we would not be able to begin processing the petition in a timely 
    On January 21, 2003, the Center sent a Notice of Intent to sue for 
violating the Act by failing to make a timely 90-day finding on the 
petition to list the Gentry indigo bush. On September 17, 2003, the 
Center filed a complaint against the Secretary of the Interior and FWS 
for failure to make a 90-day petition finding under section 4 of the 
Act for the Gentry indigo bush. In a Stipulated Settlement Agreement, 
signed June 14, 2004, we agreed to submit a 90-day finding to the 
Federal Register by January 31, 2005 [Center for Biological Diversity 
v. Norton, CV 03-473-TUC-FRZ (D. Az)]. This notice constitutes our 90-
day finding for the petition to list the Gentry indigo bush.

Biology and Distribution

    Gentry indigo bush is an erect perennial shrub that grows from a 
woody root crown and can be up to 1 meter (m) (3.2 feet (ft)) tall. It 
is a member of the Leguminosae (Pea) Family. The leaves are compound, 
3-6 centimeters (cm) (1.2-2.4 inches (in)) long with 9-17 pairs of 
leaflets. The leaflets are hairless, notched at the tip, and dotted 
with punctuate (translucent pitted glands or colored dots) glands on 
the lower surface. The flowers are sessile (lacking a stalk), 6 
millimeters (mm) (0.24 in) in length, and are presented in oblong 
clusters. The flower petals are rose-purple. Plants flower in the 
spring, from late March to mid-May. They may produce a second set of 
flowers in late summer and fall in response to monsoon precipitation.
    Howard S. Gentry originally described the species in 1950. It is a 
distinctive member of the genus Dalea with no closely related species 
(Gentry 1950, Barneby 1977). The main distinguishing character that 
serves to separate this

[[Page 5402]]

species from other sympatric species is the presence of elongate, brown 
tentacle-like glands on the calyx (the outer whorl of flowering parts) 
lobes, floral bracts (the reduced or modified leaf subtending a 
flower), and branches.
    Gentry indigo bush has been known historically from only three 
areas in southern Arizona: the west and north sides of the Baboquivari 
Mountains (Tohono O'odham Nation), the Coyote Mountains (Mendoza 
Canyon), and Sycamore Canyon (Coronado National Forest) in the Atascosa 
Mountains. Today, the only known extant population in the United States 
is in Sycamore Canyon. The plant was located in Mexico (NE of Huasabas 
in the State of Sonora) in 1995, and in 2004, the species was reported 
from Sierra El Humo, SSW of Sasabe, Arizona, in northwestern Sonora, 
Mexico (L. Hahn, pers. comm., 2004). (The 2004 location information was 
not included in the petition.) There was no population information 
provided on the Mexican locations.
    It is likely that the species still persists in the Baboquivari 
Mountains, but there have been no recent surveys to verify the presence 
of the species. These sites are within the Tohono O'odham Nation, and 
surveys could only be conducted by Tribal members or with permission 
from the Tribe. A status report for Gentry indigo bush was completed in 
1992 (Gori et al.), and all of the known historical locations (except 
on the Tohono O'odham Nation) were surveyed. Areas of suitable habitat 
were also surveyed. No plants were found in the Coyote Mountains, and 
the authors surmised in the status report that the population was 
extirpated, possibly due to past grazing practices. In the status 
report the authors stated, ``Mendoza Canyon was heavily grazed by 
cattle and dominated by Acacia greggii (catclaw acacia) to an extent we 
have rarely encountered in Southern Arizona. Such heavy cover of 
invasive shrubs is indicative of a long history of overgrazing.'' No 
plants were located in any of the other areas surveyed, including 
canyons in the following mountain ranges in Sonora, Mexico: Sierra 
Cibuta, La Colorada, Sierra el Tigre, Sierra los Ajos, Sierra Azul, 
Arroyo Las Fresnos, Sierra San Diego, La Angostura, and Sierra San Luis 
(Gori et al. 1992).
    Gentry indigo bush grows in scattered patches at elevations of 
1,097 to 1,219 m (3,600 to 4,000 ft) in Sycamore Canyon and several 
side channels. Plants are usually found on floodplain terraces in sandy 
or gravel soils, or, less commonly, on talus slopes close to the 
floodplain. The usual tree canopy for Gentry indigo bush consists of 
Arizona sycamore (Platanus wrightii), Arizona ash (Fraxinus velutina), 
Arizona walnut (Juglans major), and several oak species. Plants can be 
found growing under these trees or out in the open. Gentry indigo bush 
grows in the semi-active floodplain, meaning they are exposed to 
periodic flooding and scouring events. Observations made by Gori et al. 
(1992) and Falk (1993) support the idea that plants are adapted to 
periodic, low-intensity floods. Plants that had been covered with 
sediment were found to be growing up through the deposited material. 
The plants reproduce vegetatively (asexually) and roots almost always 
connect young plants to nearby larger clumps. To date, there has been 
no documented sexual reproduction in the field. In fact, plants rarely, 
if ever, have been observed to produce seed (Falk 1993, Gori et al 
1992). Staff from the Desert Botanical Garden collected approximately 
50 seeds from plants they assumed to be Gentry indigo bush in 1998, but 
no germination tests have been conducted (K. Rice, pers. comm. 2004).
    This species has adaptations to withstand periodic, low-intensity 
flooding, but the population in Sycamore Canyon has experienced 
population fluctuations, some of those associated with flood events. 
Following severe winter flooding in 1993, a large portion of a 
monitoring plot that had been established on a floodplain terrace 
washed away and the population declined to 15-30 plants (Falk 1993). 
Gori et al. (1992) estimated that there were 1,400 ``individuals'' in 
Sycamore Canyon before the heavy rains of 1993.

Previous Federal Actions

    Gentry indigo bush was determined to be a candidate species as 
published in the 1980 Plant Notice of Review (45 FR 82480). A species 
with candidate status is one for which we have collected and assessed 
information sufficient to propose listing the species. The removal of 
candidate status for Gentry indigo bush was published on April 2, 1998 
(63 FR 16217). The reasons supporting removal from the candidate list 
were (1) the taxon was more abundant or widespread than previously 
believed or not subject to any identifiable threats; and (2) the FWS 
had insufficient information on biological vulnerability and threats to 
support issuance of a proposed rule to list. However, as described 
below, subsequent information from the U.S. Forest Service describes a 
significant decline in the only known U.S. population.

Status Concerns

    Gentry indigo bush has always been considered rare. Gori et al. 
(1992) refer to the species as ``extremely rare.'' The loss of the 
population documented from Mendoza Canyon in the Coyote Mountains 
increased concerns regarding this rare taxon. Gentry indigo bush was 
once collected on the west slope of the Baboquivari Mountains. Toolin 
(1982) was unable to locate the species in 1981 and observed that the 
habitat had been ``exceedingly modified'' by overgrazing. This 
observation lends some uncertainty to the status of the populations on 
the Tohono O'odham Nation as the grazing regime is unknown in this 
area. Given these circumstances, attention on this species in the 
United States has been focused on the remaining population in Sycamore 
Canyon. As stated earlier, numbers of that population fluctuated 
dramatically between 1992 and 1993; numbers dropped from 1,400 to 
between 15-30 plants. Additional survey work in Mexico has documented 
at least two locations of Gentry indigo bush from Mexico, but we have 
no information on the size of those populations. Also, we have no 
information related to the threats to these populations and are unaware 
of any protection for these sites.
    A status report (Toolin 1982) documented only 100 plants from 
Sycamore Canyon. The Sycamore Canyon population was assessed in 1997 
(Bertelsen), and 499 individuals were located. A survey by Brooks 
(1999) found 194 plants in Sycamore and Penasco Canyons (a tributary to 
Sycamore). Since that time, there has been no systematic survey of 
Sycamore Canyon to determine the status of this population. A Forest 
Service biologist reported seeing some patches of Gentry indigo bush 
while surveying for Sonora chub in the canyon (2000, 2001).
    An internal memorandum to our files (Roller 1998) concluded ``the 
species capacity to recover does not negate the threat of extirpation 
to this extremely localized endemic, as it relates to extreme flood 
events within the watershed.'' We also expressed concern with the 
observed lack of seed production as this leaves the species without an 
effective seed bank that would be needed in order to recover from a 
catastrophic flood event.

Conservation Status

    Under section 4(a) of the Act, we may list a species on the basis 
of any of five factors, as follows: ``(A) the present or threatened 
destruction, modification, or curtailment of its habitat or range; (B) 
overutilization for commercial,

[[Page 5403]]

recreational, scientific, or educational purposes; (C) disease or 
predation; (D) the inadequacy of existing regulatory mechanisms; (E) 
other natural or manmade factors affecting its continued existence.'' 
The petitioners contend that four of the five factors (A, C, D, and E) 
are applicable to the Gentry indigo bush (see below). A brief 
discussion of how each of the five listing factors applies to the 
Gentry indigo bush follows:
    Factor A: The present or threatened destruction, modification, or 
curtailment of its habitat or range.
    With respect to Factor A, the petitioners cite the loss of plants 
and alteration of habitat associated with livestock grazing as threats 
to the Gentry indigo bush. The petitioners note that Gentry indigo 
plants are palatable to livestock, subject to trampling, and that 
livestock grazing may alter the stream dynamics associated with Gentry 
indigo bush habitat. The alteration of stream habitat includes soil 
compaction, streambank erosion, and removal of riparian vegetation. 
Although the Gentry indigo bush may benefit from some disturbance due 
to its ability to reproduce asexually, increased surface runoff, higher 
intensity floods, stream downcutting, and increased scouring and 
deposition could contribute to the elimination of populations.
    Information currently available indicates that the loss of plants 
and habitat to these causes may be a significant threat to the status 
of this species. Toolin (1982) states, ``Habitat of this species in 
canyons on the west slope of the Baboquivari Mountains where this 
species formerly occurred has been exceedingly modified by over-grazing 
by livestock, and that population has apparently been extirpated.'' 
Gori et al. (1992) concluded, ``Our surveys of Sycamore and Mendoza 
Canyons lead us to believe that grazing constitutes a threat to D. 
tentaculoides. We observed direct evidence of livestock browsing on, 
and even uprooting, the species in lower Sycamore Canyon where trespass 
cows from Mexico enter the canyon up to an impassable narrows.''
    Sycamore Canyon is within the boundaries of the Coronado National 
Forest, Nogales Ranger District. It is also within a designated 
Research Natural Area (Goodding RNA). Livestock grazing is not 
permitted within the boundaries of the RNA, but trespass cattle use has 
been a sporadic problem (U.S. Department of Agriculture 1998). Cattle 
have been observed in the upper reaches of the canyon (Falk pers. 
observation, Brooks 1999), and Brooks noted heavy cattle use below 
``the narrows,'' most likely attributable to trespass livestock from 
Mexico. In 1997, the Forest Service proposed a set of actions in 
Sycamore Canyon to protect the federally threatened Sonora chub (Gila 
ditaenia). One of those actions included building a fence at the 
northern portion of the canyon to restrict livestock access to the 
riparian areas. If this fence is maintained, it could help alleviate 
problems with cattle in the upper reaches of Sycamore Canyon. However, 
trespass cattle from Mexico are another problem. Sycamore Canyon 
extends south into Mexico. Historically, the border fence has been in a 
state of continual disrepair. In the fall of 1998, 2.4 kilometers (km) 
(1.5 miles (mi)) of fence along the border was repaired. We do not know 
the current condition of this fence. Recent increases in undocumented 
U.S. and Mexico border crossing activity contribute to the fence being 
continually cut.
    Watershed degradation maybe a concern in this canyon. The Bear 
Valley allotment surrounds Sycamore Canyon. It is 9,197.5 hectares (ha) 
(22,710 acres (ac)) in size. Site-specific soil surveys (2002) 
indicated that 75 percent of the allotment is in satisfactory 
condition, 16 percent impaired, 8 percent unsatisfactory and 1 percent 
is unsuitable condition. A Forest Service hydrologist (Lefevre 2000) 
concluded, ``Mankind's influence on Sycamore Canyon is mostly related 
to downcutting of the channel system, sediment movement, and sediment 
yield to the stream. Human settlement and cattle grazing, and the roads 
associated with these activities, has resulted in erosion rates above 
that which would be expected under unroaded, unmined and ungrazed 
conditions. The effects of this additional sediment may be seen in the 
reaches of the channel where deposits of gravel have filled pools. 
Downcut channel reaches may also be attributed to mankind's effects on 
the uplands because peak flows were artificially increased during the 
past century.''
    The movement of water and sediment in Sycamore Canyon may have 
affected the plants. After the 1993 El Ni[ntilde]o winter rains, most 
of the monitoring plot had been washed away and the plant population 
had experienced a dramatic decline, with more than 90 percent of the 
known individuals washed away or covered with sediment. Recovery has 
been slow; at last count there were only 194 plants in Sycamore Canyon 
(Brooks 1999). That is only 14 percent of the 1,400 plants documented 
in 1992. The watershed conditions in the Sycamore Canyon drainage may 
have contributed to the current status of Gentry indigo bush.
    Factor B: Overutilization for commercial, recreational, scientific, 
or educational purposes.
    With respect to Factor B, the petitioners did not provide 
information. We also have no information on the overutilization of this 
plant species for commercial, recreational, educational, or scientific 
    Factor C: Disease or predation.
    With respect to Factor C, the petitioners again referred to the 
plant's palatability, both to livestock and rabbits. They provided one 
observation of a plant being almost totally eaten by a rabbit (Brooks 
1999). We acknowledge that rabbits may eat plants, but do not think 
this constitutes a major threat to the species because of the size of 
mature plants. We have already discussed the effects of livestock 
grazing on Gentry indigo bush under Factor A.
    Factor D: The inadequacy of existing regulatory mechanisms.
    With respect to Factor D, the petitioners cite the inadequacies of 
the protections put forth by the Forest Service for the Goodding RNA 
and Sycamore Canyon. The Forest Service has stated that Gentry indigo 
bush is afforded a high level of protection because it shares its 
habitat with critical habitat of the federally listed Sonora chub. The 
Forest Service has done much work to improve the habitat of Sonora 
chub, including removal of a road at the mouth of Sycamore Canyon, 
protection of riparian areas at the northern end of Sycamore Canyon, 
and the expansion of the Goodding RNA. These actions have contributed 
to improvement of Sonora chub habitat and perhaps to Gentry indigo bush 
    There are several other possible management concerns in the canyon. 
The cutting of the border fence with Mexico continues to be an issue. 
Until this is resolved, cattle from Mexico will continue to enter 
Sycamore Canyon and graze on Gentry indigo bush. Undocumented migrants 
crossing the border into the United States also use this area. Human 
traffic associated with this activity in the canyon bottom may directly 
trample plants and is likely contributing to Gentry indigo bush habitat 
    The amount of sediment and surface runoff within the Sycamore 
Canyon watershed may continue to affect Gentry indigo bush. The plants 
have adaptations for persisting with flood events, but it is unknown 
when the threshold will be crossed, in terms of the magnitude of flows, 
that will likely remove the population from the canyon. Recovery may be 
hampered by the seemingly low reproductive potential of this plant. The 
Forest Service maintains

[[Page 5404]]

a road density of 0.58 km/km2 (0.93 mile/mi2) 
within the watershed and considers these roads to be ``a primary source 
of erosion and sediment'' (Lefevre 2000). The Forest Service has no 
plans to address the effects of roads in Sycamore Canyon watershed; 
thus there will continue to be sediment deposition and scouring in and 
along the stream channel.
    Sycamore Canyon is a very popular place for recreation. The 
petitioners cite trampling and compaction of soils from foot traffic as 
negatively affecting the Gentry indigo bush in Sycamore Canyon. Gentry 
indigo bush plants grow on the floodplain terraces where hikers often 
create trails to avoid walking in the stream (Falk, pers. observation). 
Due to its narrow width, there are limited terraces in the canyon 
intensifying the use of Gentry indigo bush habitat as places to create 
trails. These activities degrade habitat and may reduce the areas 
occupied by Gentry indigo bush. We know of no plan to address the 
effects of recreation in this area.
    The Forest Service has not systematically monitored the species on 
its land. While lack of monitoring is not a direct threat to the 
species, it does prevent us from adequately assessing the current 
status of the population. New information would greatly enhance our 
status review.
    Two locations have been noted in Mexico. We have no information on 
population status or threats at these sites. We are not aware of any 
protection for these areas. As such, until further information is 
provided, we do not know how the Mexican populations will contribute to 
the status of this species.
    Factor E: Other natural or manmade factors affecting its continued 
    With respect to Factor E, the petitioners cite the rarity of the 
species and the possible extinction risk associated with stochastic 
events such as drought, flood, and wildfire. This species would most 
likely be negatively affected by environmental stochasticity 
(variations over time in the population's operational environment) and 
natural catastrophes (Menges 1991). We agree, based both on information 
presented by the petitioner and other information in our files. The 
most likely scenario is that of catastrophic flooding. Increased 
rainfall combined with an altered hydrograph in Sycamore Canyon may 
result in the species being washed out. Long-term drought (as the one 
we are currently in) may affect the species' ability to recover. The 
combination of small population size, reduced reproductive potential, 
and isolation makes this species vulnerable to extinction.


    On the basis of our review, we find that the petition presents 
substantial information indicating that listing the Gentry indigo bush 
may be warranted. The main potential threat to the species appears to 
be loss of plants and habitat associated with heavy livestock use, an 
altered hydrograph in Sycamore Canyon, sediment loads in the Sycamore 
Canyon watershed, and the effects of recreation and other human uses of 
the drainage. There is also a possible increased risk of extinction 
associated with small, isolated populations from stochastic events.
    We have reviewed the available information to determine if the 
existing and foreseeable threats pose an emergency. We have determined 
that an emergency listing is not warranted at this time, because the 
population has recovered in some degree, the population is within a RNA 
with some protections, and the potential exists for additional 
populations in Mexico. However, if at any time we determine that 
emergency listing of the Gentry indigo bush is warranted, we will seek 
to initiate an emergency listing.
    The petitioners also requested that critical habitat be designated 
for this species. We always consider the need for critical habitat 
designation when listing species. If we determine in our 12-month 
finding that listing the Gentry indigo bush is warranted, we will 
address the designation of critical habitat in the subsequent proposed 

Public Information Solicited

    When we make a finding that substantial information is presented 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 on 
the Gentry indigo bush. 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 concerning the status of the Gentry 
indigo bush. 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, especially where it occurs 
in Mexico.
    If you wish to comment or provide information, you may submit your 
comments and materials concerning this finding to the Field Supervisor 
(see ADDRESSES section).
    Our practice is to make comments and materials provided, including 
names and home addresses of respondents, available for public review 
during regular business hours. Respondents may request that we withhold 
a respondent's identity, to the extent allowable by law. If you wish us 
to withhold your name or address, you must state this request 
prominently at the beginning of your submission. However, we will not 
consider anonymous comments. To the extent consistent with applicable 
law, we will make all submissions from organizations or businesses, and 
from individuals identifying themselves as representatives or officials 
of organizations or businesses, available for public inspection in 
their entirety. Comments and materials received will be available for 
public inspection, by appointment, during normal business hours at the 
above address.

References Cited

    A complete list of all references cited herein is available upon 
request from the Field Supervisor (see ADDRESSES section).


    The primary author of this document is Mima Falk, Tucson Sub-Office 
(see ADDRESSES section).


    The authority for this action is the Endangered Species Act of 
1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: January 25, 2005.
Marshall Jones,
Acting Director, Fish and Wildlife Service.
[FR Doc. 05-1905 Filed 2-1-05; 8:45 am]