Aquifer biofilm-forming isolates from the Edwards Aquifer, Texas, were characterized biochemically and by phylogenetic analyses based on partial 500 bp 16S rRNA sequencing. Five of the 8 strains evaluated were gram-negative and the other 3 were gram-positive. Phylogenetic analyses suggested novelty of 3 isolates, and biochemical analysis showed a range of carbon-source use patterns among the isolates. Such baseline information will be useful for investigating biofilm population interactions, as well as understanding the microbial ecology of unpolluted karst aquifers.

In 2004, we studied the life history and ecology of a population of Pardosa sierra (Araneae, Lycosidae) from Cave Creek Canyon (Chiricahua Mountains, Arizona). Peak abundance for immatures occurred in July, September, and October. About 64% of all adult males and females were observed in April and May. Females were observed carrying egg sacs between 5 April and 3 August. Diet composition consisted primarily of beetles (18.4%), flies (15.3%), and ants (12.2%). Spiders were active during the day, as well as at night. Immatures and adults preferred sandy or rocky substrates, respectively. Under controlled laboratory conditions, the life cycle consisted of 9 instars, and mean carapace width increased from 0.66 mm (instar 1) to 2.26 mm (instar 9: adult males and females). Clutch size ranged from 35 to 92 (mean = 67.81). Gestation period ranged from 22 to 27 days (mean = 24.06). Significant positive correlations were found between female mass and size, offspring mass and size, female size and clutch size, and female size and clutch mass. Mean total clutch mass was 34.9% of mean female mass.

Relative frequencies of heterozygous inversions in a natural population of Drosophila willistoni from a locality of Veracruz, Mexico, were determined during the period from January 1994 to January 2001. An analysis of 636 chromosomes was performed on smears of salivary glands. Of the 70 known inversions present in the species, I detected only 45 of them, representing 64.3% of the total. Most of these 45 inversions had frequencies <10%. Six were found only once in the sampling period; the remaining appeared more than twice, with an erratic presence and variable relative frequency. Inversions A, F, and G of the XL chromosome arm were present in all samples, as was inversion E of the IIR chromosome arm and inversion B from the third chromosome. The inversions that attained average frequencies >10% were inversion A (chromosome XL), inversion E (IIR), and inversion B (III). Changes in the relative frequencies in some inversions were detected for the period studied. The average number of heterozygous inversions per female ranged from 1.92 to 3.77, with an average for the entire sampling period of 2.57. Thus, this Mexican population of D. willistoni possesses a considerable degree of chromosomal polymorphism.

One hundred and four caddisfly species within 42 genera and 17 families were collected from 93 stream sites in the xeric landscape of the lower Colorado River Basin, USA. Species richness showed a significant negative correlation with channel embeddedness. Forestland had higher species richness than grassland, desert, or urban caddisfly assemblages, and fewer caddisfly species occurred in the salt-cedar (Tamarix) than in willow-alder (Salix-Alnus) and cottonwood-sycamore (Populus-Plantanus) riparian communities. Hydroptilidae comprised nearly 35% of the average relative abundance of caddisflies and were generally tolerant of impaired stream environments. Hydroptila arctia composed the greatest relative proportion of species. Adjusted specific conductance and channel embeddedness metrics showed close agreement with published tolerance values for caddisfly species listed by the U.S. Environmental Protection Agency; genera were in less agreement. Amphicosmoecus canax, Brachycentrus americanus, Culoptila moselyi, Glossosoma ventrale, Ochrotrichia ildria, Psychoglypha schuhi, and Ylodes reuteri were most commonly associated with streams with low salinities and low embeddedness, whereas Cheumatopsyche enonis, Hydropsyche auricolor, Hydroptila ajax, Hydroptila arctia, Neotrichia okopa, Smicridea signata, and Smicridea fasciatella reached highest numeric importance in streams with high salinities and embeddedness.

We studied allozyme diversity of the endemic Caddo madtom, Noturus taylori, over its small geographic range (<2,000 km²) in the Ouachita Highlands of southwestern Arkansas. This small catfish species exhibited marked genetic divergence among rivers and low levels of genetic variation within sampling localities. The more widely distributed brindled madtom, Noturus miurus, exhibited nearly identical patterns of genetic divergence among river localities separated by similar geographic distance, and similarly low levels of variation within localities were observed. We compared genetic results from madtoms to those obtained in a previous study of 2 co-distributed, endemic darter species and found that habitat specialists, especially those restricted to head-waters, are likely to show high levels of genetic divergence at relatively small spatial scales. Comparative genetic and ecological study of these endemic species suggests that an interaction of extrinsic (larger rivers with higher silt loads) and intrinsic (habitat preferences) barriers to fish movement contributes to population structure in the Ouachita Highlands. Species that specialize on headwater habitats might be particularly vulnerable to local extirpation because natural recolonization from adjacent rivers is unlikely.

We monitored an inland population of American alligator (Alligator mississipiensis) in Lake Raven, Huntsville State Park, Walker County, Texas from September 2000 to August 2001. We found alligators exhibited year-round activity in Lake Raven, with the lowest occurrence of alligators in December and January. The greatest numbers of alligators were surveyed in June and September. However, in September, 47% of the observed individuals were hatchlings. Water temperature was a significant predictor of alligator activity over air temperature and explained 37% of the observed variation in seasonal activity. A population index estimated that Lake Raven supported 0.19 alligators per hectare, with most of these alligators being juveniles and in the size class of 0.6 to 0.9 m. We also found alligators used all regions of the perimeter of the lake and were observed mostly 5 m from the shoreline. Because there is limited information on inland alligator populations in Texas, this study offers information on the seasonal activity, relative abundance, and size-class structure of alligators inhabiting a relatively small (85 ha) and highly disturbed inland lake. This information might be useful for future studies and comparisons with coastal alligator populations.

Ranches are being converted to low-density exurban housing developments in the Southwest, with potentially significant but little studied impacts on biological diversity. We counted cottontail rabbits (Sylvilagus audubonii and S. floridanus) in a grassland and in a mesquite-oak savanna in southeastern Arizona, on 48 plots evenly divided among landscapes that were grazed by livestock, or embedded in housing developments, or both, or neither. Cottontails were more abundant in exurban neighborhoods than in undeveloped areas, independent of grazing. They also were more common on ungrazed than on grazed lands, independent of development. Counts were positively correlated with the number of homes near plots. Counts also were positively correlated with height of ground cover and percent tree canopy, but only among plots in undeveloped landscapes. These results are consistent with the hypothesis that cottontails benefited from exurban development because of increased cover provided by structures and landscaping, especially in areas such as open grasslands with relatively little natural cover.

We classified displacements between axis deer (Axis axis) and fallow deer (Dama dama) by age, sex, species, and intensity (contact, non-contact) at high-quality, supplemental food patches on a Texas ranch. Axis deer males performed significantly fewer interspecific displacements than fallow deer males in fall and winter, whereas fallow deer males performed significantly fewer interspecific displacements than axis deer males in summer. Fallow deer males required significantly less intensity to displace axis deer males than conspecifics in both fall and winter. Fallow deer females engaged in significantly fewer displacements than axis deer females in winter and spring, and axis deer females required significantly less intensity to displace fallow deer females than conspecifics in winter. Heterospecific displacements between axis deer and fallow deer males correlated with the proportion of fallow deer males in hard antler. Fallow deer female displacements correlated with season. We concluded that interspecific dominance interactions between males of these 2 species are resolved by differences in the developmental stage of antlers and aggressiveness.

In southern Texas, the lack of free-standing water that results from low rainfall or poor water quality can be deleterious to wildlife. Water quality can deteriorate rapidly due to evaporation during summer in southern Texas, and high concentrations of salts in water can cause physiological distress; however, little research has addressed water quality and needs of wildlife in arid environments. Our objectives were to: 1) establish water use patterns of wildlife during summer, 2) correlate visitation rates to temperature and rainfall events, and 3) monitor water quality in earthen stock ponds and concrete troughs during summer. We recorded visits to water by 17 species of wildlife and cattle. Cattle, feral pigs (Sus scrofa), and white-tailed deer (Odocoileus virginianus) had peak watering times that differed from one another. Track surveys showed a generally negative correlation between rainfall and wildlife watering frequency. Troughs had significantly higher total dissolved solids and pH than ponds on both study sites. There was no effect of month on pH or total dissolved solids. Total dissolved solid concentrations for water sources on one study site were fair to excellent for livestock, whereas 2 sources on the other study site approached the maximum allowable limit.

We present the first summary of the status and distribution of the Benton cave crayfish (Cambarus aculabrum). The range of this endangered crayfish is limited to 4 sites globally (3 in Benton County and 1 in Washington County, Arkansas). The identity of the species at these 4 sites is based upon morphological and genetic studies. The identities of cave crayfish inhabiting 2 additional Benton County sites remain undetermined. The current population census is 40 individuals. Threats to the species are analyzed, and subsequent conservation measures recommended. Habitat degradation remains a threat to the species, especially for water quality. Analyses from 1983 to 2002 document nutrient pollution of the subterranean stream habitats, originating from sources such as septic system discharge and run-off from confined animal feeding operations.

This study updates the status, expands the range, and summarizes conservation activities to date for the bristly cave crayfish, Cambarus setosus. A new state record for this crayfish is reported after its discovery at 2 sites in 2 counties (Benton and Independence counties, Arkansas). This makes C. setosus the fifty-eighth crayfish species known from Arkansas. This is also the first record of C. setosus from the Salem Plateau of the Ozark Plateaus ecoregion; it was known previously only from the Springfield Plateau of Missouri. The range of C. setosus in Missouri includes the counties of Barry, Christian, Dade, Greene, Jasper, Lawrence, McDonald, Newton, and Stone; it is not presently known from Oklahoma, as previously reported. Cambarus setosus is probably a species complex with genetic variability at the subspecific level, especially in southwestern Missouri. Cambarus setosus is now known from 50 sites, but only 164 individuals (tallied from the most recent census at each site). This crayfish has been impacted by both habitat degradation and scientific study. Conservation organizations have begun preserving cave entrances, but conservation activity is lacking in subterranean stream recharge zones. Increased protection is recommended, including federal listing under the US Endangered Species Act.

The range of the endangered Hell Creek Cave crayfish (Cambarus zophonastes) is expanded to include a second population, determined by genetic analyses. This crayfish is still restricted to Stone County, Arkansas, and is known from only 14 individuals at Hell Creek Cave and 9 individuals at Nesbitt Spring Cave. Despite this range extension, Cambarus zophonastes remains vulnerable to extinction. Water quality sampling of Hell Creek Cave did not detect any major contamination, although numerous potential point and nonpoint source pollutants exist in the watershed. Habitat degradation remains an important threat to this species. Recovery plan implementation status and conservation activities were reviewed and recommendations made.

On 9 July 2002, while sampling a flowing segment of the North Fork Ninnescah River 10 km upstream from Cheney Reservoir, Reno County, Kansas, we observed and collected dead and dying specimens of 5 fish species. We attribute the fish kill to high water temperature, which reached 38.0°C on this day.

Ovarian follicular development and ovulation were studied by ultrasound scanning in the Mexican viviparous lizard Barisia imbricata. A linear ultrasound unit with variable capacity from 5 to 10 MHz was used. Vitellogenic follicle diameters ranged from 3.3 to 9.8 mm and were present in the lizards between September and December. Also, corpora lutea and uterine eggs were identified. The ultrasound is an excellent non-invasive technique to determine seasonal reproductive changes and can be combined with other techniques to monitor the reproductive process.

We documented the effects of inadvertent nest destruction from road maintenance activities on the survivorship, reproductive success, and breeding dispersal of burrowing owls (Athene cunicularia) breeding in natural burrows along the water delivery system in the Imperial Valley of California. The activities affected 4 nests (7 adult owls) along an 800-m section of road, filling in or destroying all of the burrows. Three of 7 adult owls in the impacted area were killed, 2 of 2 active nests failed, 2 nests that had previously failed were destroyed and might have led to the dispersal of the surviving adults. We suggest that artificial burrows will reduce the conflict between maintenance and burrowing owl nests, which will benefit both owls and landowners.

Overall, trapping of brown-headed cowbirds (Molothrus ater) on Fort Hood, Texas, has reduced parasitism on black-capped vireos (Vireo atricapilla). However, parasitism remained high (92.0% in 1999) on a disjunct, 20-ha patch of habitat. As an alternative to trapping, we shot cowbirds for 1 h per week in this patch during the 2000 and 2001 breeding seasons, removing up to 7 female cowbirds each season. Parasitism decreased following shooting (0 to 25%) and did not immediately revert to the pre-shooting level one year following the cessation of shooting. An increase in fledgling success from 0% prior to shooting to 75 to 100% following shooting suggests that shooting had a positive effect on vireo nest success. Our results from one study site suggest that minimal-effort shooting might be an effective alternative to trapping in mitigating cowbird parasitism threats.

While monitoring songbird nests using video cameras in May 2005, we documented a woodrat (Neotoma) depredating an adult female and nestling yellow-eyed junco (Junco phaeonotus) in the Santa Catalina Mountains, Arizona. Based on elevation (2,750 m) and the forest type surrounding the depredated nest, we believe that the woodrat was probably N. mexicana (although we cannot exclude N. albigula). Woodrats are considered herbivorous and have never been observed depredating vertebrate prey. This observation demonstrates that woodrats have greater dietary plasticity than previously thought.

Nyctinomops macrotis, the big free-tailed bat, is relatively uncommon in the southwestern United States, and diet information for this species is sparse. The objective of this study was to examine the diet of N. macrotis in Big Bend National Park, Texas, by using fecal analysis to determine what these bats ate in an area where they were sympatric with 3 other species of free-tailed bats. We collected and analyzed fecal samples from 40 individuals and obtained the following results: Lepidoptera (87.5% volume, 100% frequency), Hemiptera (4.1% volume, 22.5% frequency), Coleoptera (4.6% volume, 17.5% frequency), Orthoptera (1.1% volume, 12.5% frequency), unidentified insects (2.4% volume, 30.0% frequency). The diet of N. macrotis largely overlapped that of the Mexican free-tailed bat (Tadarida brasiliensis) and pocketed free-tailed bat (Nyctinomops femorosaccus) in Big Bend National Park. However, N. macrotis consumed significantly more lepidopterans and significantly less hemipterans and coleopterans when compared to these other 2 molossid species. In addition, proportions of insects taken differed among the 3 bat species in some months.

A male gray bat (Myotis grisescens) was discovered on private property in Tishomingo County, northeastern Mississippi, on 20 September 2004. The endangered gray bat previously had been known only from a site known as Chalk Mine in the northeastern corner of the county, where it was last documented in 1967. The 2004 specimen was recorded approximately 42 km south of the Chalk Mine site. The discovery of this specimen is noteworthy because it represents the first gray bat documented for the state of Mississippi in 37 years.

The range of the eastern pipistrelle (Pipistrellus subflavus) recently has expanded westward in the United States. New records of this species have been reported along the entire western boundary of its range from South Dakota to Texas. In August 2004, we captured an adult, male eastern pipistrelle at Carlsbad Caverns National Park in southeastern New Mexico. Our record represents the second capture of this species in New Mexico and the first in the southern part of the state. Because no eastern pipistrelle was captured at this site during previous surveys (1973 to 2003), this record represents the continued westward expansion of the distribution of this species in the United States.

Flight speeds of adult common vampire bats (Desmodus rotundus) were investigated in Colima, Mexico, during 2005. Individuals were captured in a small abandoned irrigation tunnel and transported to a nearby flyway (simulated cave passage) constructed in forested habitat. Using stopwatches, rates of travel were measured over a known distance. Males averaged 13.82 km/h (range 9.6 to 27.3 km/h; n = 18) and females 13.36 km/h (range 7.2 to 23.4 km/h; n = 29). Flight speeds of males and females were not significantly different. Contrary to some previous studies, no significant correlation was found between length of forearm and flight speed. Our findings provide the first report of flight speeds for D. rotundus.

Mearns's squirrel (Tamiasciurus mearnsi) is an endemic species of the montane forest of the Sierra de San Pedro Mártir in Baja California. Despite having been described for the first time in 1893 and a listing as threatened by Mexican authorities, no information is available on the ecology of this southernmost Tamiasciurus. We observed the ecology of Mearns's squirrels during 2004 and 2005. Mearns's squirrel apparently does not form larderhoards, known as middens, or leaf nests commonly built by other members of this genus. We observed Mearns's squirrels to feed heavily on tree seeds and fungi. We noted males with scrotal testes and a female in estrus in late spring. We did not observe eastern gray squirrels (Sciurus carolinensis), introduced to the western Sierra in 1946, within the areas that we searched for T. mearnsi. Mearns's squirrels might possess unique adaptations for their persistence in the dry, open forest of the Sierra de San Pedro Mártir.

The desert bighorn sheep (Ovis canadensis mexicana) was extirpated from most of its range in northern Mexico and the southwestern United States by the 1980s. Several populations have been established through reintroductions in both countries, but none in the Chihuahua–Sonora border region, where we report here 3 recent records. These records suggest the possibility of reintroducing bighorn sheep in northwestern Chihuahua and northeastern Sonora to increase the long-term viability of the species in the region.

Bighorn sheep (Ovis canadensis) occasionally have small, procumbent maxillary canines that do not penetrate the gums. However, the frequency of these vestigial teeth is only 3%. We collected 25 skulls from an isolated and indigenous population of bighorn sheep in the Silver Bell Mountains, Arizona. We compared the frequency of maxillary canines with data reported in scientific literature and in the mammalogy collection at the University of Arizona, and found a significantly higher frequency of maxillary canines in bighorn sheep skulls from the Silver Bell Mountains than in skulls collected throughout the southwestern United States. We separated skulls by sex and age and found that male and female skulls (>6 months of age at death) from the Silver Bell Mountains both had a significantly higher frequency of maxillary canines than did skulls from the Southwest. Lamb skulls (<6 months of age at death) exhibited a higher frequency of maxillary canines than did lamb skulls from throughout the Southwest; however, our small sample size (Silver Bell, n = 5; Southwest, n = 12) was statistically inconclusive. The trait for maxillary canines might be maintained or inflated because of genetic isolation from other bighorn sheep populations.

The behavior of startled desert mule deer (Odocoileus hemionus eremicus) has been described, but distances moved after being startled have not been reported. We located 8 radio-collared deer (6 females, 2 males) for 8 mo, intentionally approaching them afoot until we startled them, waited 15 min, and relocated them (≤90 min). The deer were startled and relocated 56 times. Mean time elapsed between startling and relocation was 34.5 min (SE = 3.9 min). Mean distance moved was 893.2 m. When researchers disturb mule deer before obtaining data describing movement or habitat use, they should abandon their attempts for 24 h to avoid bias in those data.