Endangered and Threatened Wildlife and Plants; Proposed Endangered Status for the Salt Creek Tiger Beetle (Cicindela nevadica lincolniana, 5101-5117 [05-1669]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 70, Number 20 (Tuesday, February 1, 2005)]
[Proposed Rules]
[Pages 5101-5117]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-1669]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AE59


Endangered and Threatened Wildlife and Plants; Proposed 
Endangered Status for the Salt Creek Tiger Beetle (Cicindela nevadica 
lincolniana)

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
list the Salt Creek tiger beetle (Cicindela nevadica lincolniana) as 
endangered under the authority of the Endangered Species Act of 1973, 
as amended (Act). The Salt Creek tiger beetle, a member of

[[Page 5102]]

the family Cicindelidae, is endemic to the saline wetlands of eastern 
Nebraska and associated streams in the northern third of Lancaster 
County and southern margin of Saunders County in Nebraska, where it is 
found in barren salt flat and saline stream edge habitats. Of six known 
populations in 1991, three are now extirpated and the remaining three 
are small and highly threatened by further habitat destruction, 
degradation, and fragmentation. These three small populations of Salt 
Creek tiger beetles are vulnerable to local extirpations from random 
natural events and human-induced activities. This proposal, if made 
final, would extend Federal protection and recovery provisions of the 
Act to the Salt Creek tiger beetle.

DATES: We will consider all comments on this proposed rule received by 
the close of business on April 4, 2005. Requests for a public hearing 
must be received by March 18, 2005.

ADDRESSES: If you wish to comment, you may submit your comments and 
materials concerning this proposal by one of several methods:
    1. You may submit written comments to Field Supervisor, U.S. Fish 
and Wildlife Service, Nebraska Ecological Services Field Office, 203 
West Second Street, Federal Building, Second Floor, Grand Island, 
Nebraska 68801.
    2. You may hand deliver comments to our office at the address given 
above or send via fax (facsimile: 308/384-8835).
    3. You may send comments via electronic mail (e-mail) to: fw6_
sctbeetle@fws.gov. See the Public Comments Solicited section below for 
file format and other information about electronic filing.
    The complete file for this proposed rule is available for 
inspection, by appointment, during normal business hours at the U.S. 
Fish and Wildlife Service, Nebraska Ecological Services Field Office, 
203 West Second Street, Federal Building, Second Floor, Grand Island, 
Nebraska 68801.

FOR FURTHER INFORMATION CONTACT: Mr. Steve Anschutz, Field Supervisor, 
at the address listed above (telephone: 308/382-6468, extension 12; 
facsimile: 308/384-8835).

SUPPLEMENTARY INFORMATION:

Background

    The Salt Creek tiger beetle is an active, ground-dwelling, 
predatory insect that captures smaller or similar-sized arthropods in a 
``tiger-like'' manner by grasping prey with its mandibles (mouthparts). 
Salt Creek tiger beetle larvae live in permanent burrows in the ground 
and are voracious predators, fastening themselves by means of abdominal 
hooks to the tops of their burrows and rapidly extending outward to 
seize passing prey. Eighty-five species and more than 200 subspecies of 
tiger beetles of the genus Cicindela are known from the United States 
(Boyd et al. 1982). The Salt Creek tiger beetle is 1 of 32 species and 
subspecies of tiger beetles that have been recorded in Nebraska.
    Tiger beetle species occur in many different habitats, including 
riparian habitats, beaches, dunes, woodlands, grasslands, and other 
open areas (Pearson 1988; Knisley and Hill 1992). Individual tiger 
beetle species are generally highly habitat-specific because of 
oviposition and larval sensitivity to soil moisture, composition, and 
temperature (Pearson 1988; Pearson and Cassola 1992). A common 
component of tiger beetle habitat appears to be open sunny areas for 
hunting and thermoregulation (an adaptive behavior to use sunlight or 
shade to regulate body temperature) (Knisley et al. 1990; Knisley and 
Hill 1992). Although tiger beetles have been well studied as a 
taxonomic group, the Salt Creek tiger beetle, an inhabitant of an 
extremely limited habitat type (i.e., barren salt flats and saline 
stream edges of the saline wetlands and associated streams of eastern 
Nebraska) has, until recently, received very little ecological study.
    Originally, the Salt Creek tiger beetle was described by Casey 
(1916) as a separate species of C. lincolniana. Willis (1967) 
identified C. n. lincolniana as a subspecies of C. nevadica which 
evolved from C. n. knausi; this is the currently accepted taxonomic 
classification. The evolution of C. n. lincolniana is a result of its 
isolation from the gene pool sometime after the Kansan, but possibly 
during the Yarmouth glaciation. There also are spatial separations 
between C. n. knausi and C. n. lincolniana. C. n. knausi has been 
collected in Sheridan and Garden Counties in the Nebraska Sandhills, a 
distance of several hundred miles from the saline wetlands and 
associated streams of eastern Nebraska that provide habitat for the 
Salt Creek tiger beetle.
    The Salt Creek tiger beetle is metallic brown to dark olive green 
above, with a metallic dark green underside, and measures 1.3 
centimeters (cm) (0.5 inch (in)) in total length. It is distinguished 
from other tiger beetles by its distinctive form and the color pattern 
on its dorsal and ventral surfaces. The elytra (wing covers) are 
metallic brown or dark olive green, and the head and pronotum (body 
segment behind the head) are dark brown (Carter 1989).
    Leon Higley (L. Higley, University of Nebraska-Lincoln (UNL), pers. 
comm. 2002) believes the Salt Creek tiger beetle has a 2-year life 
cycle, not uncommon for tiger beetles. Adults are first observed as 
early as the end of May or as late as mid-June, and disappear by mid to 
late July. Their numbers peak about 2 weeks after the first individuals 
appear and begin to feed and mate. After mating, the male rides atop 
the female, presumably preventing her from re-mating, a phenomenon 
known as mate-guarding. Females lay their eggs along sloping banks of 
creeks in areas where the salt layer is exposed in the soil horizon, in 
barren salt flats of saline wetlands, and along saline stream edges 
that are found in close association with water, near a seep or stream. 
Researchers from UNL speculate that, during the night, female Salt 
Creek tiger beetles lay about 50 eggs (Farrar 2003).
    Spomer and Higley (2001) describe the life cycle of the Salt Creek 
tiger beetle in detail through egg, larval, and adult stages, as 
follows. After the egg hatches, the young larva digs a burrow and uses 
its head to scoop out soil. The larva takes these small mud clods to 
the burrow entrance and flips them outside the hole. Larval burrows 
occur within a few inches of the water's edge. The small larva waits at 
the top of its burrow and ambushes prey that passes too near the burrow 
entrance. Once it has captured its prey, the larva pulls it into the 
burrow with the aid of three hooks on the dorsum of the fifth abdominal 
segment. These hooks also function to prevent the larva from being 
pulled from its burrow by larger prey or predators. The larva will plug 
its burrow and retreat inside during periods of high water, very hot 
weather, or very dry conditions. As the larva grows, it molts to a 
larger instar (a life stage between molts), enlarging and lengthening 
its burrow. For the most part, a Salt Creek tiger beetle larva will 
remain active until cold weather, and then it plugs its burrow and 
hibernates. The Salt Creek tiger beetle has three instars. It probably 
overwinters as a third instar, pupates in May, and emerges as an adult. 
Before pupation, the larva seals its burrow entrance and digs a side 
chamber about 5 to 8 cm (2 to 3 in) below the soil surface. After the 
adult emerges from the pupa, it remains in the chamber until its 
cuticle hardens. Steve Spomer (S. Spomer, UNL, pers. comm. 2002) 
postulates that adult Salt Creek tiger beetles live for approximately 6 
weeks.

Distribution and Status

    The Salt Creek tiger beetle occurs in saline wetlands--on exposed 
saline mud flats and along mud banks of streams and seeps that contain 
salt deposits (Carter 1989; Spomer and

[[Page 5103]]

Higley 1993; LaGrange 1997; Nebraska Game and Parks Commission (NGPC) 
1999). Adults are confined to moist, muddy areas within a few yards of 
wetland and stream edges. Salt Creek tiger beetles require these open 
barren areas for construction of larval burrows, thermoregulation, and 
foraging (S. Spomer, pers. comm. 2002; L. Higley, pers. comm. 2002). 
The density of larval burrows decreases as vegetative cover increases 
(S. Spomer, pers. comm. 2002; R. Harms, U.S. Fish and Wildlife Service, 
pers. obs. 2001). The Salt Creek tiger beetle is adapted to brief 
periods of high water inundation and highly saline conditions (Spomer 
and Higley 1993).
    Saline wetlands in eastern Nebraska occur in swales and depressions 
within the floodplain of Salt Creek and its tributaries in northern 
Lancaster and southern Saunders Counties. LaGrange (1997) suggests that 
the saline wetlands of eastern Nebraska receive their salinity from 
groundwater passing through an underground rock formation containing 
salts deposited by an ancient sea that once covered Nebraska. Saline 
wetlands of eastern Nebraska are characterized by saline soils and 
halophytes (plants adapted to saline conditions). Saline wetlands 
usually have a central area that is devoid of vegetation, and when dry, 
exhibit salt encrusted mudflats (barren salt flats) (LaGrange 1997). 
This is the area used by the Salt Creek tiger beetle and numerous other 
saline-adapted insects. Although Murphy (1992) indicated that 
historically there were approximately 7,300 ha (18,000 ac) of saline 
wetlands in eastern Nebraska, the distribution of the Salt Creek tiger 
beetle was limited to specific habitats within those wetlands. These 
habitats included barren salt flats (devoid of vegetation) and moist, 
unvegetated saline streambanks of Salt Creek and its tributaries in the 
northern third of Lancaster County and southern margin of Saunders 
County.
    We examined the insect collection at the UNL State Museum to assess 
the historical distribution of the Salt Creek tiger beetle. From 1900 
through 1918, 11 collectors collected 134 Salt Creek tiger beetles (B. 
Ratcliffe, State Museum, UNL, pers. comm. 2003). Of these 134 Salt 
Creek tiger beetles, 81 beetles (60 percent) were collected from an 
area identified as Salt Basin; the remaining 53 Salt Creek tiger 
beetles were collected in other unidentified areas in Lincoln, 
Nebraska. Salt Basin, also referred to as Salt Lake, is now called 
Capital Beach Lake (Cunningham 1985; Farrar and Gersib 1991). We also 
reviewed files from the NGPC's Natural Heritage Program and found 
records of Salt Creek tiger beetles in the Snow Entomological 
Collection of the Natural History Museum at the University of Kansas, 
and a private collection by Walter Johnson (M. Fritz, Nebraska Natural 
Heritage Program, NGPC, pers. comm. 2003). Significant collections of 
the Salt Creek tiger beetle from Salt Lake (Capital Beach) in 1964, 
1965, 1970, and 1972 are housed at the Snow Entomological Collection. 
Additional queries of various museums around the country found Salt 
Creek tiger beetles in the Natural History Museum of Los Angeles, 
California (B. Harris, Natural History Museum of Los Angeles, pers. 
comm. 2003) and the Orma J. Smith Museum of Natural History, Caldwell, 
Idaho (J. Wood, Orma J. Smith Museum of Natural History, pers. comm. 
2003). Based on our examination of collections and the review of 
records, all known Salt Creek tiger beetle specimens were collected in 
areas identified as either Salt Basin or Salt Lake (and now known as 
Capital Beach) or the City of Lincoln, Nebraska.
    The insect collections provide some information about the 
historical distribution of the Salt Creek tiger beetle. More 
importantly, this information documents the presence of the Salt Creek 
tiger beetle at Capital Beach from the date of the first collection 
there in 1900 to the last in 1972. Thus, we have concluded that between 
1900 and 1972, Salt Creek tiger beetles were present in numbers large 
enough to sustain a population at Capital Beach. The size of this 
population is not known. In 1984, Mark Carter, a graduate student in 
entomology at UNL and Steve Spomer, associate entomology professor at 
UNL, conducted visual searches for the Salt Creek tiger beetle at 
Capital Beach and other sites that appeared to provide suitable habitat 
(Spomer and Higley 2001). They found a low number of adults at Capital 
Beach, but provided no information on population numbers, and noted 
that the habitat had been degraded at Capital Beach (Spomer and Higley 
1993). By 1998, surveyors did not observe any Salt Creek tiger beetles 
at Capital Beach, and the species has not been found there since, 
despite surveys being conducted annually through 2002 (Spomer et al. 
2002).
    The Salt Creek tiger beetle has one of the most restricted ranges 
of any insect in the United States (Spomer and Higley 1993) only 
occurring along limited segments of Little Salt Creek and adjacent 
remnant salt marshes in Lancaster County, Nebraska. Intensive visual 
surveys conducted by UNL entomologists from 1991 through 2004 found 
Salt Creek tiger beetles at a total of 13 sites in northern Lancaster 
and southern Saunders Counties, although beetles were not found, nor 
were surveys conducted, at all 13 sites in all 14 years (Spomer et al. 
2002 and 2004). The 13 survey sites are identified by: (1) Locality 
(street or road name); (2) local name; or (3) land owner name. Visual 
counts of adults were made by researchers walking across the barren 
salt flats and along the edges of saline streams on sunny days during 
mid to late June when the population of emerged adults is and at its 
greatest abundance (S. Spomer, pers. comm. 2001; Allgeier et al. 2003). 
Evening counts also were conducted using a black light (ultraviolet), 
because the Salt Creek tiger beetle is highly attracted to this type of 
light source. Visual surveys during the day and night were conducted 
using the same techniques for all years and all sites surveyed (S. 
Spomer, pers. comm. 2002), and the surveys in all 14 years were 
conducted by the same researcher, which would reduce surveyor bias and 
ensure consistency among survey years.
    Pearson and Cassola (1992) found that tiger beetle population size 
can be accurately estimated through visual counting due to the relative 
ease of observing and counting individuals, and because of their 
specialized habitat requirements. Visual counts, although having 
limitations (Horn 1976), can provide relative estimates and, if 
conducted in a similar manner every year, a good estimate of the health 
and stability of populations (Allgeier et al. 2003). Furthermore, harm 
to the insect is limited using visual survey techniques because 
experienced researchers are able to identify the insect without 
handling it.
    In addition to the visual surveys, researchers undertook a mark/
recapture study for the first time in 2002. Prior to 2002, researchers 
were unable to find a permanent marker that could be used to 
distinguish marked and unmarked beetles (a prerequisite for mark/
recapture studies) (Spomer and Higley 1993; S. Spomer, pers. comm. 
2001). In 2002, UNL entomologists discovered a paint marker that would 
adhere to the beetles' elytra (Allgeier et al. 2003). This allowed 
researchers to conduct a mark/recapture study using Salt Creek tiger 
beetle adults captured at Little Salt Creek across from Arbor Lake, 
north of the Interstate 80 and North 27th Street Interchange in 
Lincoln, Nebraska. The Little Salt Creek site was used because visual 
surveys revealed that this site harbored the highest number of adult 
beetles.
    Although its use for estimating the true population size for the 
Salt Creek tiger beetle is somewhat limited by a

[[Page 5104]]

small sample size, the mark/recapture study did establish that Salt 
Creek tiger beetles marked at the Little Salt Creek site traveled to 
other nearby survey sites. Allgeier et al. (2003) found two marked 
adult Salt Creek tiger beetles at Arbor Lake, a saline wetland 
separated from Little Salt Creek by a 2-lane gravel road. They had 
moved a distance of 460 and 365 meters (m) (1,509 and 1,198 feet (ft)), 
respectively, from where they were originally marked. Based on results 
of the 2002 mark/recapture study, we have concluded that Salt Creek 
tiger beetle adults are mobile and can move to nearby suitable 
habitats.
    We examined data from the 1991 to 2004 survey sites and determined 
that some of these sites could be combined to identify different 
populations of Salt Creek tiger beetles based on the following 
criteria: (1) Close proximity of sites (i.e., nearby, contiguous, or 
neighboring) to each other; (2) distances of less than 805 m (2,640 ft) 
separating sites; and (3) the combination of survey sites satisfying 
criteria 1 and 2, and providing both suitable saline wetland (i.e., 
barren salt flats) and stream (saline edges) habitats forming a saline 
wetland/stream complex. The distance used in criterion 2 above (805 m 
(2,640 ft)) are based on the 2002 mark/recapture study by Allgeier et 
al. (2003), which established that Salt Creek tiger beetles can move 
among nearby suitable habitats, as well as the distance at which Salt 
Creek tiger beetles may be attracted to artificial sources of light.
    On the basis of the above criteria, our evaluation of the 13 survey 
sites resulted in the delineation of six different populations of Salt 
Creek tiger beetles, half of which have been extirpated since annual 
surveys began in 1991 (a population is considered extirpated after 2 
consecutive years of negative survey results). The six Salt Creek tiger 
beetle populations, including the three that have been extirpated, are 
described below in order of abundance based on visual surveys conducted 
from 1991 to 2004: (1) Little Salt Creek-Arbor Lake; (2) Little Salt 
Creek-Roper; (3) Upper Little Salt Creek-North; (4) Upper Little Salt 
Creek-South; (5) Jack Sinn Wildlife Management Area (WMA); and (6) 
Capital Beach.

Little Salt Creek-Arbor Lake Population

    The Little Salt Creek-Arbor Lake population contains the largest 
number of Salt Creek tiger beetles. The abundance of Salt Creek tiger 
beetles there is expected, given the large, relatively intact saline 
wetland complex within which the population occurs. The Little Salt 
Creek-Arbor Lake population is located approximately 1.6 km (1 mi) 
north of the Interstate 80 and North 27th Street Interchange on the 
northern city limits of Lincoln, Nebraska. It exists along the saline 
stream edge of Little Salt Creek and on the barren salt flats of an 
adjacent saline wetland. This population was monitored at up to three 
survey sites from 1991 to 2004. The population averaged 329 individuals 
per year over that 14-year period. Visual surveys for the entire Little 
Salt Creek-Arbor Lake Population in 1991-2004 found 171, 94, 62, 376, 
459, 437, 406, 254, 208, 225, 434, 511, 583, and 392 adult individuals, 
respectively (Spomer and Higley 1993; Spomer et al. 1997, 1999, 2001, 
2002, and 2004; and Allgeier et al. 2003). In addition, a mark/
recapture study conducted in 2002 estimated that the population size 
was approximately 970 adult Salt Creek tiger beetles, with 95 percent 
confidence (an estimate of precision) that the true population is 
between 704 and 1,606 adults (Allgeier et al. 2003). Both visual 
surveys and the mark/recapture study show that this population is very 
small when compared to known populations of other tiger beetle species, 
even including the federally listed threatened Northeastern beach tiger 
beetle (C. dorsalis dorsalis) and Puritan tiger beetle (C. puritana). A 
comparison of population sizes of Salt Creek tiger beetles, 
Northeastern beach tiger beetles, and Puritan tiger beetles is 
discussed below.

Little Salt Creek-Roper Population

    The Little Salt Creek-Roper population is the second largest 
remaining population of Salt Creek tiger beetles, based on visual 
surveys conducted from 1994 to 2004. This population is located 
immediately south of the Interstate 80 and North 27th Street 
Interchange, and approximately 1.6 km (1 mi) downstream of the Little 
Salt Creek-Arbor Lake population. Similar to the Little Salt Creek-
Arbor Lake population, this population is associated with a saline 
wetland and stream complex located along Little Salt Creek. Visual 
surveys were conducted on up to three survey sites from 1994 to 2004, 
but only one site was surveyed from 1994 to 1997. A second site was 
added in 1998, after the Lower Platte South Natural Resource District 
was deeded a restored saline wetland as part of a mitigation 
requirement for a Department of the Army permit issued by the U.S. Army 
Corps of Engineers (Corps) under section 404 of the Clean Water Act 
(CWA). However, researchers from UNL found only one Salt Creek tiger 
beetle at the restored wetland in 1998 and none since then (Spomer et 
al. 1999, 2001, 2002, and 2004; Allgeier et al. 2003). In 2001, UNL 
researchers found 28 Salt Creek tiger beetles on a privately owned 
saline wetland adjacent to Little Salt Creek and across the stream from 
the restored mitigation wetland, after the landowner granted permission 
to conduct visual surveys (Spomer et al. 2001, 2002, and 2004; Allgeier 
et al. 2003). We consider this private saline wetland as the third site 
of the Little Salt Creek-Roper population because of its location and 
close proximity to the two other sites. A fourth site was also surveyed 
in 2004, resulting in the observation of three Salt Creek tiger 
beetles. The number of adult individuals of the Little Salt Creek-Roper 
Population found at all 4 sites in 1994-2004 was 54, 161, 151, 144, 45, 
55, 80, 85, 258, 162, and 154, respectively (Spomer et al. 1997, 1999, 
2001, 2002, and 2004; Allgeier et al. 2003). A mark/recapture study was 
not conducted on this population of Salt Creek tiger beetles due to the 
small population size and a limited window of opportunity.

Upper Little Salt Creek-North Population

    The Upper Little Salt Creek-North population is the third and last 
extant population of Salt Creek tiger beetles. This population is 
located approximately 7.2 km (4.5 mi) upstream from the Little Salt 
Creek-Arbor Lake population, and exists only on the saline stream edges 
of Little Salt Creek. Although former saline wetlands (i.e., barren 
salt flats) exist adjacent to this population, these wetlands are 
degraded (drained because of the incisement of Little Salt Creek) and 
no longer provide suitable habitat for the Salt Creek tiger beetle. 
This population is comprised of four sites along Little Salt Creek that 
were surveyed from 1991 to 2004. Over the course of the 14-year survey 
period, 2 of the survey sites that comprise this population were 
surveyed at least 10 times. A third site was surveyed in 1994, 1998, 
2002, and 2003. The survey of a new and fourth site in 2002 by UNL 
researchers resulted in the observation of one Salt Creek tiger beetle 
(Spomer et al. 2002; Allgeier et al. 2003). From 1991 to 1996, the 
number of adult beetles found in the Upper Little Salt Creek-North 
Population averaged 32 individuals per year (Spomer and Higley 1993; 
Spomer et al. 1997). Since then, the number of adult beetles surveyed 
in the population has averaged five individuals per year. The number of 
adult individuals found during visual surveys in 1991-2004 was 24, 32, 
48, 35, 14, 41, 0, 4, 8, 4, 0, 8, 0, and 12, respectively (Spomer and 
Higley 1993;

[[Page 5105]]

Spomer et al. 1997, 1999, 2001, 2002, and 2004; Allgeier et al. 2003). 
L. Higley and S. Spomer (pers. comm. 2002) presumed that this 
population would be extirpated because of the low and decreasing number 
of adults found during surveys. A mark/recapture study was not done for 
this population due to the small population and a limited window of 
opportunity.

Upper Little Salt Creek-South Population

    The Upper Little Salt Creek-South population was located 
approximately 5 km (3 mi) upstream from the Little Salt Creek-Arbor 
Lake Population. Degraded and non-functioning saline wetlands exist 
adjacent to Little Salt Creek, and although once devoid of vegetation, 
saline stream edge habitats are now vegetated at this site. This 
population's only known site was surveyed in 1991-2004 revealing 7, 5, 
4, 8, 3, 0, 0, 0, 0, 0, 0, 0, 0, and 0 adult individuals, respectively 
(Spomer and Higley 1993; Spomer et al. 1997, 1999, 2001, 2002, and 
2004; Allgeier et al. 2003). The Upper Little Salt Creek-South 
Population is considered to be extirpated because no Salt Creek tiger 
beetles have been found there since 1995.

Jack Sinn Wildlife Management Area Population

    Salt Creek tiger beetles from sites comprising the Jack Sinn WMA 
population have not been found since 1998 (Spomer et al. 1999, 2001, 
2002, and 2004; Allgeier et al. 2003). This population was made up of 
one survey site located on Rock Creek in southern Saunders and northern 
Lancaster Counties, approximately 20 km (10 mi) northeast of the Little 
Salt Creek-Arbor Lake population. This population of Salt Creek tiger 
beetles was on property owned by NGPC. Surveys for the Salt Creek tiger 
beetle in 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2001, 2002, 
2003, and 2004, found 15, 11, 1, 0, 0, 1, 1, 0, 0, 0, 0, and 0 adult 
individuals, respectively (Spomer and Higley 1993; Spomer et al. 1997, 
1999, 2001, 2002, and 2004; Allgeier et al. 2003). The Jack Sinn WMA 
Population is considered to be extirpated because no Salt Creek tiger 
beetles have been found there since 1998. Loss and fragmentation of 
barren salt flat and stream habitats likely resulted in the loss of 
this population.

Capital Beach Population

    Capital Beach was once one of the largest saline wetland tracts in 
eastern Nebraska, with a size of approximately 162 ha (400 ac) 
(Cunningham 1985). Although we do not have any information on the 
number of Salt Creek tiger beetles that existed historically at Capital 
Beach, we have concluded, based on the number of museum and private 
collection specimens collected at Capital Beach (i.e., Salt Basin) 
since the early 1900s, that a sustainable population of Salt Creek 
tiger beetles once was present there. All that remains of suitable 
habitat at Capital Beach now is a 10- to 20-m (40- to 50-ft) wide ditch 
that parallels Interstate 80 for approximately 0.8 km (0.5 mi), located 
west of the Interstate 80 and North 27th Street Interchange. Visual 
surveys for Salt Creek tiger beetles from this population were 
conducted in 1991, 1992, 1995, 1998, 1999, 2001, 2002, 2003, and 2004 
with 12, 8, 0, 4, 0, 0, 0, 0, and 0 adult individuals found, 
respectively (Spomer and Higley 1993; Spomer et al. 1997, 1999, 2001, 
2002, and 2004; Allgeier et al. 2003). No individuals have been found 
at Capital Beach since 1998 (Spomer et al. 2002 and 2004; Allgeier et 
al. 2003), leading us to conclude that this population is now 
extirpated.

Conclusion of Salt Creek Tiger Beetle Population Review

    The Salt Creek tiger beetle, highly specialized in habitat use, has 
probably always been rather localized in distribution. Information from 
surveys conducted from 1991 through 2004 and from museum collections 
show that the number of known populations has declined from six to 
three. Salt Creek tiger beetles were last found in the Upper Little 
Salt Creek-South population in 1995, and no individuals have been found 
in either the Jack Sinn WMA or the Capital Beach populations since 
1998. Thus, we have determined that three known populations of Salt 
Creek tiger beetles have been extirpated in the last 9 years.
    Surveys conducted over a 14-year period establish that the Salt 
Creek tiger beetle is an extremely rare insect, numbering only in the 
hundreds and confined to an extremely small range. Visual surveys 
conducted in 1991-2004 show substantial annual fluctuations with 229, 
150, 115, 473, 637, 631, 550, 308, 271, 309, 519, 777, 745, and 558 
adult tiger beetles found each year, respectively, although not all 
sites were surveyed in all years (Spomer and Higley 1993; Spomer et al. 
1997, 1999, 2001, 2002, and 2004; Allgeier et al. 2003). In addition, 
in 2002, a mark/recapture study undertaken to calculate a total 
population estimate for the largest Salt Creek tiger beetle population, 
the Little Salt Creek-Arbor Lake population, resulted in an estimate of 
970 adult beetles with a 95 percent confidence interval of 704 to 1,606 
beetles (Allgeier et al. 2003).
    Survey and mark-recapture results indicate that the number of Salt 
Creek tiger beetles, as well as the number of populations, is extremely 
small, even when compared to other federally-listed tiger beetle taxa. 
From 1989 to 1992, the number of Northeastern beach tiger beetles found 
during annual surveys at 65 sites in Maryland and Virginia ranged from 
9,846 to more than 17,480 beetles (U.S. Fish and Wildlife Service 
1994). Surveys of Puritan tiger beetles in Maryland in 1989, 1991, 
1992, and 1993 found an average of 6,389 beetles at 15 sites annually 
(U.S. Fish and Wildlife Service 1993). Both the Northeastern beach 
tiger beetle and Puritan tiger beetle are well-studied insects and were 
listed as threatened under the Act in 1989 (55 FR 32088).
    Based on our analysis of private and public insect collections, 
NGPC's Heritage database records, surveys conducted over the past 14 
years, and professional opinions of UNL entomologists who have studied 
or are studying the Salt Creek tiger beetle, we conclude that the 
number of Salt Creek tiger beetle populations is declining and that the 
three remaining populations are immediately threatened with extinction.

Previous Federal Action

    On November 15, 1994, we published in the Federal Register (59 FR 
58982), an Animal Notice of Review which included the Salt Creek tiger 
beetle as a Category 2 candidate species for possible future listing as 
either a threatened or endangered species. Category 2 candidates were 
those taxa for which information contained in the Service's files 
indicated that listing may be appropriate, but for which additional 
data were needed to support a listing proposal. In the subsequent 
February 28, 1996, Candidate Notice of Review published in the Federal 
Register (61 FR 7596), we indicated that the Category 2 candidate 
species list was being discontinued, and that henceforth the term 
``candidate species'' would be applied only to those taxa that would 
have earlier fit the definition of the former Category 1 candidate 
taxa, that is, those species for which we had on hand sufficient 
information to support a listing proposal. In 2000, based on an 
assessment of imminent threats, the Salt Creek tiger beetle became a 
candidate species for listing and was assigned a listing priority 
number of 6. On October 30, 2001, the Salt Creek tiger beetle was 
upgraded to a priority 3 candidate for Federal listing, based on a 
review of the status, distribution, threats, and

[[Page 5106]]

imminence of such threats (66 FR 54808). A priority 3 is the highest 
priority ranking in the Candidate Notice of Review that can be assigned 
to a subspecies. A priority 3 candidate faces an imminent, high-
magnitude threat.
    In 1995, we entered into a cooperative agreement with the UNL to 
conduct 2 years of Salt Creek tiger beetle surveys in saline wetlands 
of eastern Nebraska and associated saline streams to assess and 
quantify changes in the species' populations that were apparent from 
earlier surveys. Results of the 1995 and 1996 surveys were discussed 
above in the Distribution and Status section of this rule. Further, the 
UNL researchers agreed to determine oviposition sites and larval 
habitats of the Salt Creek tiger beetle, initiate studies of genetic 
diversity within the C. nevadica complex, and increase public awareness 
of the Salt Creek tiger beetle through education and outreach. In 2001, 
we entered into a new and expanded cooperative agreement with the UNL 
to: (1) Conduct surveys to determine Salt Creek tiger beetle abundance 
and distribution in the Salt Creek watershed; (2) initiate procedures 
for rearing Salt Creek tiger beetles in captivity for possible 
reintroduction into previously occupied and unoccupied suitable 
habitats; (3) determine the physiological basis for habitat preferences 
of female Salt Creek tiger beetles for ovipositing, both in field and 
laboratory settings; (4) determine egg and larval survivorship of the 
Salt Creek tiger beetle; and (5) determine whether Salt Creek tiger 
beetles are attracted to specific artificial light sources and the 
distance at which such light sources would attract beetles. In 
addition, the Service also provided the NGPC with funding in both 2001 
through 2004 through section 6 of the Act for research on the Salt 
Creek tiger beetle.
    On October 7, 2002, as part of an agreement regarding other 
species, the U.S. Department of the Interior reached an out-of-court 
settlement with several conservation organizations and agreed to make a 
final determination for listing the Salt Creek tiger beetle by no later 
than September 30, 2005.

Summary of Factors Affecting the Species

    After thorough review and consideration of all available 
information, we have determined that the Salt Creek tiger beetle 
warrants listing as an endangered species. Section 4 of the Act (16 
U.S.C. 1533) and regulations (50 CFR part 424) promulgated to implement 
the listing provisions of the Act set forth procedures for determining 
a species or subspecies to be endangered or threatened due to one or 
more of the five factors described in section 4(a)(1) of the Act. These 
factors and their application to the Salt Creek tiger beetle are as 
follows:

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

Background
    The greatest threat to the Salt Creek tiger beetle is habitat 
destruction (Ratcliffe and Spomer 2002). Like many insects, the Salt 
Creek tiger beetle's close association with specific habitats--salt 
barrens and stream edges--leaves it particularly vulnerable to habitat 
destruction and alteration through direct and indirect means (see Pyle 
et al. 1981). The effects of habitat destruction and modification on 
tiger beetle species have been documented by Knisley and Hill (1992) 
and Nagano (1982). The saline wetlands of eastern Nebraska and 
associated saline streams used by the Salt Creek tiger beetle have 
undergone extensive degradation and alteration for commercial, 
residential, transportation, and agricultural development since the 
late 1800s, and are the most restricted and imperiled natural habitat 
type in the State (Gersib and Steinauer 1991).
    In order to comprehend the complexity and immediacy of threats to 
the Salt Creek tiger beetle, it is necessary to understand when and how 
the destruction and degradation of the beetle's saline wetland and 
associated stream habitats took place. Cunningham (1985) reported that 
Salt Lake or Salt Basin (now known as Capital Beach) was once 
approximately 162 ha (400 ac) in size, and one of the largest saline 
wetlands in the area. The growing City of Lincoln (Lincoln) ditched, 
drained, and filled the saline wetlands and associated streams (Murphy 
1992). In 1895, Salt Lake was diked and Oak Creek was diverted to 
create a permanent lake for recreational purposes. In 1906, the lake 
was renamed Capital Beach. From the 1930s to the 1950s, saline wetlands 
continued to be destroyed for the development of Lincoln (Farrar and 
Gersib 1991). In the 1960s, the construction of Interstate 80, through 
the heart of the remaining Salt Creek tiger beetle habitat, resulted in 
additional filling, dredging, diking, draining, and diversion (Farrar 
and Gersib 1991). All of these commercial and residential developments 
and road construction activities resulted in the loss or degradation of 
barren salt flat and saline stream edge habitat for the Salt Creek 
tiger beetle. The best available information indicates that these 
activities may have caused the extirpation of the Capital Beach 
population, possibly the largest historical population of Salt Creek 
tiger beetles.
    The three remaining Salt Creek tiger beetle populations are being 
surrounded by commercial and residential development (Ratcliffe and 
Spomer 2002). During the 1990s, new housing, industrial, and commercial 
developments and infrastructure work degraded or destroyed many more 
acres of saline wetlands (Farrar 2003). Although the construction of 
buildings, homes, roads, schools, and parking lots is not occurring 
directly on salt flats and saline stream edges, these projects are 
occurring adjacent to these important habitats. Such projects have 
resulted in the creation of impervious surfaces (rooftops, access 
roads, storm sewers, and parking lots) that do not allow precipitation 
to seep into the ground. Instead, frequent high-volume freshwater 
runoff flows into saline wetlands, and associated streams, diluting 
salinity and altering their hydrology. In addition, runoff originating 
from other nearby, but not necessarily adjacent, residential and 
commercial developments and associated roads, flows through constructed 
drainages and storm sewers, and tributaries and contributes to an 
increase of freshwater inflow into downslope saline wetlands and their 
associated streams.
    Reduced salinity concentrations on barren salt flats and along 
saline stream edges have allowed the invasion of vegetation such as 
Typha angustifolia (cattail) and Phalaris arundinacea (reed canary 
grass) into habitats used by the Salt Creek tiger beetle. These plants, 
ordinarily unable to tolerate high salinity, are aggressive invaders 
that convert sunny, barren salt flats into habitat that is dominated by 
a herbaceous overstory, rendering it unsuitable for use by the Salt 
Creek tiger beetle. This overstory shades out open sunny areas required 
by the Salt Creek tiger beetle to thermoregulate, forage, and oviposit 
(M. Fritz, NGPC, pers. comm. 2001). Increased vegetative encroachment 
is the primary factor attributed to the extirpation of several 
populations of other Cicindela species (e.g., C. abdominals and C. 
debilis) (Knisley and Hill 1992), and is one of the main threats to C. 
ohlone (66 FR 50340).
    Reduced salinity concentrations on barren salt flats and along 
saline stream edges have also resulted in other direct impacts. Based 
on field and laboratory studies using C. circumpicta and C.

[[Page 5107]]

togata, two tiger beetle species that are co-inhabitants of salt flats 
with the Salt Creek tiger beetle, Hoback et al. (2000) found that salt 
is required for ovipositing. Neither species oviposited in greenhouse 
soil without it. Allgeier et al. (2004) concluded that species-specific 
preferences for salt and soil moisture regimes is important to habitat 
partitioning and reduction in competition between the Salt Creek tiger 
beetle and other tiger beetles. Hoback et al. (2000) discovered that 
changes in salinity and hydrology may alter the abundance of prey and 
cause the loss of suitable larval habitat for saline wetland-dependent 
species of tiger beetles, including the Salt Creek tiger beetle. After 
urban development occurs near and around saline wetlands and associated 
streams and alters the hydrologic regimes of these habitats, 
restoration and recovery of these habitat types will be difficult. This 
is especially true for the specialized barren salt flats and saline 
stream edges that are needed by the Salt Creek tiger beetle (J. 
Cochnar, U.S. Fish and Wildlife Service, pers. obs. 2002).
Past and Present Habitat Quality and Quantity
    A number of studies have attempted to quantify the amount and rate 
of habitat loss for the saline wetlands of eastern Nebraska. All of 
these studies confirm the extensive loss of saline wetlands, but vary 
in terms of their estimates for the total acres lost due to differences 
in data and methods of analysis. In 1991, Farrar and Gersib found that 
only about 490 ha (1,200 ac) of saline wetlands of eastern Nebraska 
remained, compared to 7,300 ha (18,000 ac) in the late 1800s (Murphy 
1992). In 1993 and 1994, a team of biologists from various Federal and 
State agencies completed an intensive assessment, inventory, and 
categorization of the saline wetlands of eastern Nebraska (Gilbert and 
Stutheit 1994). This assessment identified 98 sites that could be 
categorized as Category 1 saline wetlands comprising approximately 
1,346 ha (3,327 ac) (Gilbert and Stutheit 1994). Category 1 saline 
wetlands provide saline wetland functions of high value or have the 
potential to provide high value following restoration or enhancement 
(Gilbert and Stutheit 1994). Category 2 saline wetlands are 
contaminated and degraded with limited potential for restoration. 
Category 3 and 4 wetlands are defined as freshwater wetlands and 
freshwater vegetation on saline and nonsaline hydric soils, 
respectively (Gilbert and Stutheit 1994). LaGrange (2003) further 
examined the analysis completed by Gilbert and Stutheit (1994) and 
divided Category 1 saline wetlands into three sub-classes: (1) Not 
highly degraded and still functioning--totaling 85 ha (210 ac) (6 
percent); (2) degraded, but still functioning as a saline wetland and 
restorable to full function--totaling 1,249 ha (3,087 ac) (93 percent); 
and (3) degraded, not functioning as a saline wetland, but restorable 
to full function--totaling 12 ha (30 ac) (1 percent).
    Although it is important to discuss the overall loss of saline 
wetlands, the impact of that loss on the Salt Creek tiger beetle can 
only be fully assessed by considering the loss of barren salt flat and 
saline stream edge habitats that occur within the confines of Category 
1 saline wetlands. We expanded on the analyses completed by LaGrange 
(2003) and Gilbert and Stutheit (1994) to complete such an assessment. 
Using a Geographic Information System (GIS), we did a habitat 
assessment of the remaining barren salt flat and saline stream edge 
habitats existing within the remaining Category 1 saline wetlands. 
Using National Hydrography Dataset information (https://nhd.usgs.gov) 
and all known locations of Salt Creek tiger beetles, we delineated 
saline stream edge habitat (J. Runge, U.S. Fish and Wildlife Service, 
pers. comm. 2003). Next, we delineated barren salt flat habitat through 
the use of a feature-extraction process that would select areas 
containing similar spectral signatures of known barren salt flats. 
Finally, we did a qualitative evaluation of our GIS analysis by ground-
truthing select polygons within the barren salt flat GIS layer.
    Results from our assessment indicate that the total remaining areas 
of barren salt flat and saline stream edge habitat that exist within 
the saline wetlands of the Little Salt Creek, Rock Creek watersheds, 
and the remnant Salt Basin (i.e., Capital Beach) are approximately 15, 
33, and 1 ha (38, 81, and 3 ac) respectively, totaling 49 ha (122 ac). 
These 49 ha (122 ac) represent all the barren salt flat and saline 
stream edge habitats that currently remain. In consideration of the 
analysis completed by LaGrange (2003), we then conducted a spatial 
analysis to determine the amount of habitat currently available for the 
Salt Creek tiger beetle that is not highly degraded. The analysis 
separated coded barren salt flats into Category 1 subclasses identified 
by LaGrange (2003). Our analysis reveals that only approximately 6 ha 
(15 ac) out of the total 49 ha (122 ac) of coded salt barrens are not 
highly degraded. It is these remaining 6 ha (15 ac) of not highly 
degraded barren salt flats and saline stream edges that provide habitat 
for the Salt Creek tiger beetle.
    As the quality of saline habitat continues to decline through 
reduction in size, encroachment of herbaceous species, and modification 
to hydrology, so too does the likelihood that the Salt Creek tiger 
beetle can survive and avoid extinction. Most of the habitat delineated 
in our analysis was composed of extremely small habitat complexes 
(i.e., less than 0.04 ha (0.09 ac)), that are unlikely to provide all 
of the necessary life history requirements that the Salt Creek tiger 
beetle needs to survive. Further, these small habitats are in clusters 
resembling mosaics, separated by herbaceous overstory. This spatial 
dispersion of herbaceous overstory precludes the use of these small 
areas by the Salt Creek tiger beetle, a species confined to specific 
habitats, and not known to travel distances greater than 805 m (2,640 
ft) (Allgeier et al. 2003) in search of other suitable habitat. S. 
Spomer (pers. comm. 2002) confirmed that no Salt Creek tiger beetles 
were found in these small habitats in the 13 years that surveys were 
conducted. Carter (1989), the Nebraska Game and Parks Commission 
(1999), Ratcliffe and Spomer (2002), Spomer and Higley (1993 and 2001), 
Spomer et al. (1997), and Allgeier et al. (2003) all concluded that the 
declining number of populations of Salt Creek tiger beetles is due to 
the loss of suitable saline wetland and stream habitat.
Urban Development and Road Construction
    Commercial and residential urban development and road construction 
are the greatest threats to the saline wetlands of eastern Nebraska and 
the plant and animal species that depend upon these habitats (Gilbert 
and Stutheit 1994; Ratcliffe and Spomer 2002). Urban expansion of 
Lincoln and Lancaster County has contributed to the decline of the 
saline wetlands of eastern Nebraska and associated streams, and 
potential extinction of the endemic species that use these areas, such 
as the Salt Creek tiger beetle. From 1970 to 2000, the Lincoln's human 
population grew by 50 percent, with a corresponding 50 percent increase 
in the area of the City (U.S. Department of Transportation 2002a). For 
the period of 1990 to 2000, Lincoln and Lancaster County experienced a 
17.2 percent growth in population and a 20.2 percent growth in housing 
(U.S. Census Bureau 1990 and 2000). The anticipated future population 
growth rate of Lincoln and Lancaster County is 1.5 percent annually 
(City of Lincoln and Lancaster County 2002). The population of

[[Page 5108]]

Lincoln is expected to grow by approximately 47 percent by 2025 (U.S. 
Department of Transportation 2002a). This accelerated population growth 
rate has become evident in the last year, as illustrated by urban and 
infrastructure developments (discussed below) that threaten the 
continued existence of the Salt Creek tiger beetle and its limited 
remaining habitat.
    All three extant populations of Salt Creek tiger beetles may be 
threatened with extirpation caused by the expansion of urban 
development and road construction in Lincoln and Lancaster County. A 
review of 1989 and 2002 aerial photographs reveals that over 50 percent 
of the area surrounding the Little Salt Creek-Roper population (a 
1,300-ha (3,200-ac) area bounded by Interstate 80 to the North, Salt 
Creek to the South, North 27th Street to the West, and Highway 77 to 
the East) has been developed within the last 5 years. We reviewed the 
2002 City of Lincoln and Lancaster County Comprehensive Plan and found 
that an additional 30 to 40 percent of the area surrounding the Little 
Salt Creek-Roper population is planned for residential and commercial 
development over the next 25 years. However, given the current rate of 
growth and development surrounding this population, this additional 
area is likely to be developed in less time than that. In some cases, 
the local municipal development permits for this expansion have already 
been acquired (including some floodplain permits from Lincoln) (R. 
Harms, pers. obs. 2002 and 2003).
    Development with the potential to adversely impact all three 
populations is underway in areas adjacent to the remaining segments of 
habitat. Recent developments have already changed the drainage patterns 
in some areas, resulting in the introduction of excess freshwater, 
sediment, and contaminated urban runoff to saline habitats occupied by 
the Salt Creek tiger beetle. There are also planned highway projects 
which could also adversely impact the species due to freshwater runoff 
increase, vegetative encroachment, risks of toxic spills and alteration 
of drainage patterns.
    Increased vehicle traffic due to road improvements can increase the 
amount of chemically-contaminated runoff from vehicles and roadway 
surfaces flowing into Little Salt Creek. Highway runoff contains a 
variety of chemical constituents, many of which can be harmful to the 
environment when washed from roads by rain and snowmelt into adjacent 
surface waters, groundwater, and ecosystems (Bricker 1999). 
Contaminated runoff could impact the Salt Creek tiger beetle, as it can 
have toxic effects on the beetle and its prey base. For the expansion 
of Interstate 80, the Federal Highway Administration (FHWA) and 
Nebraska Department of Roads (NDOR) have identified measures that 
reduce concentrations of hazardous and toxic contaminants in highway 
runoff, and a contingency plan for accidental spills that would 
threaten two populations of Salt Creek tiger beetles (FHWA 2003). 
However, other non-Federal road and street projects that will be 
constructed after the Interstate 80 expansion do not currently address 
impacts to the Salt Creek tiger beetle from exposure to runoff.
Agriculture
    Agricultural practices in the area may also threaten the limited 
Salt Creek tiger beetle habitat and the Upper Little Salt Creek-North 
and Little Salt Creek-Arbor Lake populations. Livestock grazing can 
destroy or substantially degrade habitats for adult and larval forms of 
the Salt Creek tiger beetle, through trampling, and thus, destroy Salt 
Creek tiger beetle larvae burrows and the larvae that inhabit them. 
Cattle grazing also can compact soil and modify soil hydrology, 
gradually drying out a site and making it unsuitable for adults and 
larvae (which prefer moist, muddy sites with encrusted salt on soil 
surfaces). The Upper Little Salt Creek-North population occurs along a 
segment of Little Salt Creek that flows through a pasture, and one of 
these population survey sites may have been negatively impacted by 
cattle grazing (S. Spomer, pers. comm. 2002).
    Cultivation also poses a threat to the largest remaining population 
of Salt Creek tiger beetles, the Little Salt Creek-Arbor Lake 
population. Cultivation can increase erosion of sediment and result in 
introduction of pesticides into adjacent saline wetlands. This 
population currently is at risk because there is no vegetative buffer 
between occupied Salt Creek tiger beetle habitat and row cropped areas. 
Adverse impacts to the beetles in this population are likely to occur 
as precipitation events and periodic winter and spring thaws wash 
sediment from the cultivated land and either cover over larval burrows 
with a thick layer of sediment or encourage vegetative encroachment of 
saline stream edges through its accumulation. Future use of the 
impacted area by the Salt Creek tiger beetle may not occur because it 
may be unsuitable as ovipositing, larval, and foraging habitat. When an 
area of larval habitat becomes degraded then disappears, so does the 
species it supports (Dunn 1998). Historic and anticipated impacts 
related to flooding are discussed later in Factor E of the Summary of 
Factors Affecting the Species section of this rule.
Stream Channelization, Bank Stabilization, and Incisement
    In Nebraska, many river and stream systems, including Salt Creek 
and its tributaries, have undergone extensive channelization for flood 
control to protect both agricultural and urban developments. 
Channelization of Salt Creek from Lincoln to Ashland, Nebraska, was 
done a section at a time from 1917 to 1942 by the Corps (Farrar and 
Gersib 1991; Murphy 1992). In the 1950s, the Corps and U.S. Department 
of Agriculture further modified the area when they developed and 
implemented a flood control plan that involved the construction of 
levees, reservoirs, and additional channelization of Salt Creek (Murphy 
1992). Farrar and Gersib (1991) found that the greatest alteration of 
saline wetlands in the Little Salt Creek and Rock Creek drainages 
resulted from the channelization of Salt Creek. Channelization of Salt 
Creek encouraged tributary streams (Little Salt Creek, Oak Creek, Rock 
Creek, and Middle Creek) to head-cut, carving deeper into their beds to 
adjust to a change in stream bed gradients. Straightening stream 
channels leads to a state of disequilibrium or instability, often 
causing stream entrenchment and corresponding changes in morphology and 
stability (Rosgen 1996). The lowering of tributary streambeds resulted 
in the degradation and loss of saline wetlands by draining and lowering 
the water table and diluting the salt concentrations with freshwater 
leading to vegetative encroachment (Wingfield et al. 1992).
    In 1992, the largest population of the Salt Creek tiger beetle, the 
Little Salt Creek-Arbor Lake population, was significantly impacted by 
a stream channelization and bank stabilization project along Little 
Salt Creek (Spomer and Higley 1993; Farrar 2003). In an attempt to 
control erosion and bank sloughing and to prepare for the widening of 
North 27th Street, a portion of Little Salt Creek was straightened, and 
its banks were armored with rock riprap. These actions destroyed about 
one-half of the remaining prime habitat for the Salt Creek tiger beetle 
along Little Salt Creek (Spomer and Higley 1993; Farrar 2003). Based on 
surveys conducted in 1991 and 1992, the Little Salt Creek-Arbor Lake 
population showed a corresponding 55 percent decline (from 171 to 94) 
after the project was completed (Spomer and Higley 1993). In this 
circumstance, stabilization of about half of the bank resulted in the

[[Page 5109]]

loss of over half of the population of Salt Creek tiger beetles. Had 
the entire bank been stabilized, instead of just half, the population 
of Salt Creek tiger beetles there likely would have been extirpated, or 
nearly so. It is unclear why the population at the site was able to 
recover following such a devastating event. It is possible that 
favorable weather conditions, suitable habitat within travel distance 
(distances of less than 805 m (2,640 ft)), or other unknown factors 
could have contributed to their survival.
    The lower portion of Little Salt Creek, where the two largest 
remaining populations of Salt Creek tiger beetles exist, has been 
deeply incised by human activities, resulting in the creation of 
vertical stream banks measuring approximately 6 to 9 m (20 to 30 ft) in 
height (J. Cochnar, U.S. Fish and Wildlife Service, pers. obs. 2002; R. 
Harms, pers. obs. 2002). We observed that bank sloughing is covering 
saline stream edges and reducing the amount of suitable habitat for the 
two largest populations of Salt Creek tiger beetles. We presume that 
the Little Salt Creek-Arbor Lake and Little Salt Creek-Roper 
populations of the Salt Creek tiger beetle have been able to survive 
because these two populations exist in areas where there is still a 
functioning saline wetland and saline stream complex. However, if these 
two areas evolve into stable, vegetated, incised stream systems and the 
wetland habitats continue to receive freshwater runoff from surrounding 
urban development, the existing suitable habitats for the Salt Creek 
tiger beetle would no longer support these two populations and the Salt 
Creek tiger beetle might become extinct.

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

    Tiger beetles (genus Cicindela) are one of the most sought-after 
genera of beetles by amateur collectors because of their unique 
metallic colors and patterns and fascinating habits (Nebraska Game and 
Parks Commission 1999; 66 FR 50340). Interest in the genus Cicindela is 
reflected in a journal entitled Cicindela, which has been published 
quarterly since 1969 and is exclusively devoted to this genus. Even 
limited collection pressure on small populations of species, such as 
the Salt Creek tiger beetle, can have adverse impacts on viability 
because of the loss of genetic variability it causes (Spomer and Higley 
1993). At present, we do not know if the collection of adult Salt Creek 
tiger beetles is a factor contributing to its decline.
    The Service and NGPC are funding studies of the Salt Creek tiger 
beetle to improve the understanding of its biology and habitat 
requirements. This research will ultimately contribute to the 
conservation of the species. Transplanting larvae of other species of 
rare tiger beetles has been conducted elsewhere by removing larvae from 
one site and introducing them to another unoccupied site. For example, 
the federally threatened C. dorsalis dorsalis has been successfully 
reintroduced on the sandy beaches of the Sandy Hook National Seashore 
in New Jersey using this technique (B. Knisley, Randolph-Macon College, 
pers. comm. 2003; A. Scherer, U.S. Fish and Wildlife Service, pers. 
comm. 2003). Leon Higley (pers. comm. 2001) states that Salt Creek 
tiger beetles will need to be introduced into unoccupied suitable 
habitats through the rearing and translocation of captive larvae. 
Captive rearing of Salt Creek tiger beetle larvae for introduction into 
suitable saline habitats is under way through Service- and NGPC-funded 
UNL studies (Allgeier et al. 2003). Development of these procedures 
requires the capture and removal of a small number of adult Salt Creek 
tiger beetles from their habitat and placement in a laboratory setting. 
The removal of a small number of adults will slightly reduce a 
population, but if successful, such a program will preserve and enhance 
the genetic variability of the species.

C. Disease or Predation

    Insufficient information is available to determine if the Salt 
Creek tiger beetle is susceptible to diseases that could threaten its 
survival. However, the Salt Creek tiger beetle is affected by several 
predacious and parasitic species that are commonly observed in its 
habitat. Spiders (Salticidae and Lycosidae), predatory bugs 
(Reduviidae), beetles (Histeridae and Cantharidae), birds, shrews 
(Soricidae), raccoons (Procyon lotor), lizards (Lacertilia sp.), toads 
(Bufonidae), robber flies (Asilidae), ants (Formicidae), and 
dragonflies (Anisoptera sp.) all prey on the Salt Creek tiger beetle 
(Lavigne 1972; Nagano 1982; Pearson 1988). A robber fly was observed 
preying on a Salt Creek tiger beetle it had caught in flight and pulled 
to the ground (Spomer and Higley 2001). Ants can overwhelm, kill, and 
devour larvae confined to their burrows (Spomer and Higley 2001). 
Larger species of tiger beetles (C. circumpicta) have been known to 
prey on smaller-sized tiger beetles (C. togata), especially those 
species that occupy similar habitats (Hoback et al. 2001). Both C. 
togata and C. circumpicta are found in the same habitats as the Salt 
Creek tiger beetle and both may prey upon it (S. Spomer, pers. comm. 
2002). Parasitic wasps (Chalcididae and Tiphiidae) can sting the 
larvae, resulting in paralysis, then lay eggs which hatch and feed on 
the larvae (Spomer and Higley 2001). Bee flies (Bombylidae) hover over 
larval burrows and flip eggs into the entrances (S. Spomer, pers. comm. 
2002). After the eggs hatch, the bee fly maggots attach themselves to 
the Salt Creek tiger beetle larvae and feed on them.
    Predators and parasites play important roles in the natural 
dynamics of populations and ecosystems. Predators and parasitoids of 
the Salt Creek tiger beetle evolved in conjunction with the beetle and 
would not normally pose a severe threat to its survival. However, 
predation and parasitism of adults and larvae may account for 
significant mortality of the Salt Creek tiger beetle because of the 
small size of the remaining populations, limited distribution, reduced 
habitat, and close proximity of the two largest populations (L. Higley, 
pers. comm. 2002). Hoback et al. (2001) indicated that reduced saline 
habitats, coupled with a limited prey source, may result in predation 
by C. circumpicta and C. togata on the Salt Creek tiger beetle. Such 
predation by other tiger beetles may be a threat to the Salt Creek 
tiger beetle. However, at this time it is unknown whether the magnitude 
of predation and parasitism on the Salt Creek tiger beetle is a threat 
to its survival.

D. Inadequacy of Existing Regulatory Mechanisms

Overview
    Federal, State, and local laws, regulations, and policies have not 
been sufficient to prevent past and ongoing losses of Salt Creek tiger 
beetle habitat. Existing regulatory mechanisms that provide some, but 
not adequate, protection for the Salt Creek tiger beetle include--
Federally implemented regulatory mechanisms such as the National 
Environmental Policy Act (NEPA) and section 404 of the CWA; State 
implemented regulatory mechanisms such as the Nebraska State Water 
Quality Standards (as required by section 401 of the CWA) and the 
Nebraska Nongame and Endangered Species Conservation Act (NESCA); and 
local conservation planning efforts such as the City of Lincoln and 
Lancaster County Comprehensive Plan, the Little Salt Creek Valley 
Planning Cooperative Agreement cosponsored by the Nature Conservancy 
(TNC) and NGPC, and a local conservation plan for the

[[Page 5110]]

protection of the Salt Creek tiger beetle proposed by Lincoln (but not 
yet developed).
Federally Implemented Regulatory Mechanisms
    While NEPA and CWA are important environmental protection statutes, 
neither provides specific protection to candidate species. NEPA is a 
procedural statute that requires full consideration and disclosure of 
the environmental impacts of a project. It does not require protection 
of particular species or its habitat, nor does it require the selection 
of a particular course of action.
    Under section 404 of the CWA, the Corps does not regulate wetland 
drainages that do not result in a discharge of dredged or fill material 
into waters of the United States or sediment inputs originating from 
upland sources. The effects of such activities could have substantial 
adverse impacts on saline wetlands and associated streams used by 
larval and adult forms of the Salt Creek tiger beetle. Additionally, 
the Corps' Regulatory Program in Nebraska has limited regulatory 
authority over road and urban development projects that have destroyed 
or further degraded habitats for the Salt Creek tiger beetle. Since the 
late 1800s, over 90 percent of the historical saline wetlands of 
eastern Nebraska have been lost or highly degraded due to such projects 
(Murphy 1992), which have led to corresponding losses of Salt Creek 
tiger beetle habitat, including barren salt flats, saline stream edges, 
and seeps.
    Below is a discussion of permitted activities and prescribed 
mitigation authorized by the Corps under section 404 of the CWA. In 
1990, Lincoln purchased 23 ha (58 ac) of a portion of the saline 
wetland known as Arbor Lake and turned over its management to NGPC. 
This acquisition and protection in perpetuity served as mitigation for 
a Department of the Army permit that authorized the destruction of 7 ha 
(17 ac) of saline wetlands for the expansion of two streets. This 
mitigation resulted in the acquisition of a portion of the habitat that 
harbors the Little Salt Creek-Arbor Lake Population of Salt Creek tiger 
beetles. Since 1995, permits have been authorized for projects that 
impacted approximately 11 ha (27 ac) of eastern Nebraska Category 1 
saline wetlands (U.S. Department of Transportation 2002a and b). As 
required by these permits, project proponents offered to mitigate 
(restore and preserve) approximately 108 ha (266 ac) of Category 1 
saline wetlands (U.S. Department of Transportation 2002a and b). 
Although mitigation did not specifically target the 49 ha (122 ac) of 
Salt Creek tiger beetle habitat (i.e., barren salt flats and saline 
stream edges), one such mitigation project had the potential to benefit 
the beetle in this ar