The taxonomic status of members of the genus Lepidium in the Intermountain West has been in flux for years. Species concepts and classification of these endemic species from the western United States center on the highly variable L. montanum complex. Until recently, classification treatments that use morphological features in this group have been adequate, but as new species are discovered and more locations reported, the limited number of morphological features available for classification and defining species concepts has led to more uncertainty about taxonomic rankings. As part of a molecular and morphological-based treatment of the group, flow cytometry was used to evaluate 58 collections of Lepidium from the Intermountain West. The ploidy level for 14 species and 11 varieties of Lepidium was surveyed to assess whether ploidy levels affected the interpretation of taxonomic rankings. Of the Lepidium taxa surveyed, 90% were tetraploid, and several were diploid and hexaploid. Tetraploid occurrences crossed all major species and varieties. No geographic distribution or habitat patterns were associated with ploidy level.

The spread of introduced saltcedar (Tamarix spp.) throughout many riparian systems across the western United States motivated the introduction of saltcedar leaf beetles (Diorhabda carinulata, D. elongata; Chrysomelidae) as a biological control agent specific to saltcedar. I monitored small mammal populations for up to 12 years as saltcedar defoliation progressed at 3 of the original saltcedar beetle release sites and at an additional site where beetles established through dispersal. There was no evidence of any linear effect of increasing defoliation over time on small mammal species richness. Estimated population sizes of 4 small mammal species, based on mark-release-recapture trapping, showed linear responses to saltcedar defoliation at particular sites, but all of these species were represented by only 3 years of data at those sites. Increases in the abundance of 2 species of desert-adapted heteromyid rodents, Merriam's kangaroo rat (Dipodomys merriami) and Panamint kangaroo rat (D. panamintinus), may have occurred due to increasing habitat desertification associated with saltcedar biocontrol. Overall, however, results imply that saltcedar biological control is likely to have negligible effects on resident small mammal populations.

To better understand the impact of Melanoides tuberculata on ecosystem processes via nutrient recycling, we quantified the body size distribution, density, and ammonia-nitrogen (NH₄-N) and soluble reactive phosphorus (SRP) excretion of M. tuberculata in Rogers Spring, which is located in southern Nevada. We examined how nutrient recycling rates were related to body size and body nutrient content. We found that small individuals dominated the size structure, density, and NH₄-N and SRP excretion rates and that nutrient recycling was determined by biomass rather than by high per capita excretion rates. The NH₄-N excretion rates of M. tuberculata are between 2 and 27 times higher than the SRP excretion rates in Rogers Spring. These results indicate that M. tuberculata in Rogers Spring may be P limited and rather conservative in P recycling. In contrast to stoichiometric predictions, body nutrient content was a poor predictor of excretion rates. However, there was a close correlation between the measured and modeled NH₄-N:SRP recycling ratio (NH₄-N:SRP_r), which suggests that diet N:P is more important in predicting NH₄:SRP_r than body elemental composition. Assuming that all excreted nutrients enter the water column, we determined that M. tuberculata contributes 17.3 mg N m^-2d^-1 and 3.3 mg P m^-2d^-1 to Rogers Spring. Although densities of M. tuberculata in the spring brook were lower than those reported in other studies, we assume that these exotic snails can have a significant impact on ecosystem processes, especially by N recycling in systems with very low ambient nutrient concentrations.

Encroachment of woody plants is widespread in semiarid grasslands of the southwestern United States. Wildlife responses to shrub removal techniques in the region are relatively unknown. In 2008 and 2009, we examined avian responses to prescribed burning of ungrazed shortgrass prairie within a study area (4811 ha) near Amarillo, Texas, that is heavily encroached by honey mesquite (Prosopis glandulosa) and cholla (Opuntia spp.). Specifically, we compared relative abundance, species richness, and species diversity of breeding birds across large, spatially replicated experimental plots burned every 2 or 4 years since 2002 and unburned controls. We found no significant differences in the mean relative abundance of most species across the treatments. However, Northern Bobwhite (Colinus virginianus), Cassin's Sparrow (Peucaea cassinii), and Brown-headed Cowbird (Molothrus ater) were more abundant in less frequently burned plots and unburned controls. We found no differences in species richness or diversity across the treatments. Limited variation in avian responses across the treatments likely reflects the uniform pattern of vegetation structure we found across the plots, despite repeated application of prescribed fire at 2- and 4-year intervals over a 7-year period. Differences in bird species assemblages among the burn treatments might be more prominent in future years as prescribed burning continues.

Fallen pine cones are a microhabitat for spiders in Washington State. Eighty-nine species of spiders from 24 families and 70 genera were identified from 1060 specimens collected from over 4567 cones of Pinus ponderosa and Pinus monticola between 2008 and 2013. Euryopis formosa Banks 1908 (Theridiidae) and Pholcophora americana Banks 1896 (Pholcidae) were the most abundant species collected (27% and 9.3% of identified specimens, respectively) and occurred most frequently (49% and 21% of sampling sites, respectively). Fallen cones may be an important microhabitat for these species in Washington. Fallen cones produced 18 spider species rare in Washington, including Theridion rabuni Chamberlin and Ivie 1944 (Theridiidae), which has not been found in any other microhabitat in the state. Sampling fallen cones added a mean of 3 species (SD 2, range 0–9) to site lists created by conventional collecting methods like sweeps, litter sifting, and foliage beats. Agelenid spiders incorporated entire cones into their webs, while other species placed egg sacs or retreats on cone surfaces or used the inner spaces of cones to build prey capture webs or to molt.

With the loss and modification of natural roosting habitat afforded by caves, abandoned mines have assumed increased importance as alternative roosting sites for Townsend's big-eared bats (Corynorhinus townsendii). However, increased human safety concerns have led to accelerated abandoned mine closure programs. To protect roosting sites in mines with significant bat activity, bat-compatible gates are installed that allow continued access to mine workings. Aside from ensuring public safety, these gates provide protection from disturbance to roosting bats. We evaluated the effects of gating on bat flight behavior at maternity colonies in 2 previously gated (control) and 2 ungated (treatment) mines that were gated during this study. We used an infrared video camera to record bat flight behavior at the entrances to each of the 4 study mines for 2 consecutive mornings and a single night each month during the warm season. Entrance (03:00–06:00) and emergence (21:00–24:00) surveys comprised 3 consecutive hours. Overall circling activity increased more than 6-fold at openings of treatment mines following gating (P < 0.001). Crowding during emergence was significantly higher (P = 0.023) in newly gated mines than in previously gated mines. Gates affect subadults during the initial-volancy periods, as detected through collisions with the gates. Increased activity of bats and collisions with the gate, which result in bats falling to the ground at mine openings, may amplify vulnerability to predators and increase energetic demands.

Trimerotropis aberasturii, a new species of band-winged grasshopper, is described from the mountains of north central Nevada. It appears most closely related to T. suffusa and T. verruculata. Trimerotropis aberasturii is distinguished from the other 2 species by a more extensive black hind wing band, features of the male genitalia, and geographic distribution.

To examine genetic structure in populations of the mayfly Baetis tricaudatus and make inferences about its dispersal abilities, I analyzed 3 microsatellite regions in individuals collected from 14 locations in the San Bernardino Mountains of southern California. Genotypes separate into 2 strongly differentiated clusters, suggesting that B. tricaudatus as currently recognized consists of more than one species. Within each cluster, there is significant genetic differentiation among collection sites, but no significant trend of genetic isolation by distance. Heterozygote deficiencies exist at various sites for all loci. Gene flow appears to prevent isolation by distance across the 60-km stretch of the San Bernardino Mountains under consideration. Wahlund effects may account for the observed heterozygote deficiencies.

Fringed myotis (Myotis thysanodes) is considered a bat species of conservation concern in Colorado and in western North America. The purpose of our research was to describe the geographic and elevational distribution of fringed myotis in Colorado and consider the potential influence of the Southern Rocky Mountains on the distribution of this species. We documented, mapped, and analyzed 729 Colorado capture and occurrence records for this species, and used 546 records in a 2-way ANOVA comparing elevational distribution among sex and reproductive classes. Mean elevation of occurrence was significantly different among reproductive classes (F = 7.03, P = 0.0010) but not between sex classes (F = 0.10, P = 0.7578). These elevation results support the hypothesis that fringed myotis tend not to occur at higher elevations in the Southern Rockies. Mapped occurrence records suggest that fringed myotis exhibits a bifurcated geographic distribution, with separate populations occurring in a band along the Colorado Front Range and in western Colorado. These data suggest that the high peaks, mountain parks, and valleys of the Southern Rocky Mountains act as a set of dispersal barriers, and that movement by fringed myotis from east to west, and vice versa, across the Colorado Rockies is not a regular occurence. Finally, populations occurring in southeastern Colorado and in a band along the Colorado Front Range may potentially be at risk from increasing urbanization, changes in surface water resource availability, and exposure to diseases, such as white-nose syndrome.

The pygmy rabbit (Brachylagus idahoensis), the world's smallest rabbit, has a limited distribution due to its year round dependence on sagebrush (Artemisia tridentata) for food and shelter. Due to accelerating habitat loss from fragmentation, development, and fire, understanding the pygmy rabbit's ecology has become increasingly important. In 2010, we initiated a study of the status of a pygmy rabbit population and its habitat requirements on U.S. Bureau of Land Management (BLM) land near Woodruff in northeastern Utah. We first observed and recorded the presence of the rabbit and its use of the area, and then measured sagebrush height, density, cover, and major and minor crown widths at active burrow and potential burrow sites. We also compared understory characteristics and soil texture at active, recently abandoned, and potential burrow sites. Pellets and sagebrush samples were also analyzed to determine dietary patterns. The height, as well as the major and minor crown widths of the sagebrush, and 2 cover measurements were significantly greater at active burrow sites than at potential burrow sites (P < 0.001). Total grass and forb biomass differed between the sites, with active burrow sites having higher total biomass in the spring compared to abandoned and potential burrow sites (P < 0.05) and higher total biomass in the fall compared to abandoned sites (P < 0.05). The principle component of the soil at all sites was sand, with small amounts of silt and clay. The pygmy rabbit's annual diet consisted of 80.7% sagebrush, and the sagebrush chosen for consumption was higher in crude protein and lower in fiber than nonforaged sagebrush. Our results suggest that maintaining stands of large mature sagebrush will provide pygmy rabbits in this area with preferred burrow and foraging sites that are vital to the persistence of populations in this region.

We provide information on recent records of the 2 subspecies of striped skunk occurring in the northeastern (Mephitis mephitis estor) and northwestern (M. m. holzneri) region of Baja California, Mexico. Most of the recent records for these subspecies come from valleys and suburban zones.

Using camera traps, we recorded presence of the white-lipped peccary (Tayassu pecari; WLP) in the Chenkan region, an area of wetlands, mangroves, and tropical flood forest located on the coast of Campeche in Mexico. The WLP had been considered extinct in the area, so its rediscovery in Chenkan increases the known range of the current distribution of this species, which is classified as endangered in Mexico. The presence of WLP in Chenkan highlights the importance of the area for the conservation of this endangered species. Therefore, it is necessary to take effective conservation actions to maintain the region's natural ecosystems, which are under strong pressure from expanding agriculture and tourism infrastructure.

The northern portion of the range of Ambrysus mormon is redescribed based on collection records from national and state biomonitoring databases and other sources. The northern range limit of this species includes the Klamath River drainage along the California—Oregon border; the Middle Snake River drainage in eastern Oregon; southern and central Idaho; all of Montana except the northwest corner; North Dakota and South Dakota, west of the Missouri River; and Nebraska, north of the Platte River and west to the Missouri River.

We present the first documented record of an ocelot (Leopardus pardalis) for the Mexican state of Chihuahua. The animal was camera-trapped in open oak woodland. This finding increases the number of mammal species present in the northern Sierra Madre Occidental and reinforces the need for continuing surveys in the barrancas region of Chihuahua.