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Efforts to remove invasive species may benefit native species, but the effects can be complex and unpredictable. Thus, studies of invasive-species removal provide important information for guiding management and providing insight about variation in post-removal impacts within the community. Using southern pine-grassland ecosystems as a model system, we hypothesized that removal of the long-established red-imported fire ant (Solenopsis invicta, hereafter RIFA) would positively influence altricial Peromyscus species, due to increased survival of young in the nest and thus increased recruitment to the population, but would not impact semi-precocial hispid cotton rats (Sigmodon hispidus), which are mobile more quickly after birth and thus at less risk of depredation by RIFA. We compared small mammal populations on sites treated with a granular insecticide (Extinguish Plus) to remove RIFA in southwestern Georgia, United States, from April 2018 to December 2019. As expected, we detected no difference in cotton rat recruitment. However, contrary to our prediction, the same was true for cotton mice (Peromyscus gossypinus) and oldfield mice (Peromyscus polionotus). We found RIFA removal increased survival both of cotton rats and cotton mice, increasing average population rate of change (λ) on treated sites during the study period. In contrast, we observed lower survival of oldfield mice, with similar λ estimates on treated and untreated sites, but low sample sizes were problematic for this species. Our results show that removal of invasive species can have positive impacts for native species, but both the magnitude of RIFA effects on small mammals and mechanisms by which impacts occur are complex.

Biofluorescence in mammal pelage is considered rare, but has been documented in multiple taxa in recent years. Herein, we provide the first observations of biofluorescence in fossorial mammals. We documented biofluorescence in live Geomys pinetis (southeastern pocket gopher) and in museum specimens of four additional geomyid species. Although unknown, the adaptive significance of biofluorescence in pocket gophers is likely similar to that documented in terrestrial and arboreal species previously, including communication or predator evasion.

Animals living underground deal with multiple physiological challenges, such as hypoxia and hypercarbia, but may have reduced thermoregulation demands because of the more stable underground microclimate. Southeastern pocket gophers (Geomys pinetis Rafinesque) occur in the fire-adapted, open-pine forests of the southeastern Atlantic Coastal Plain where prescribed fire is commonly used to manage understory vegetation. They are almost exclusively fossorial, and their tunnels provide ecological services, including shelter, for a suite of commensal vertebrates and invertebrates. To quantify potential thermoregulation benefits of southeastern pocket gopher tunnels, we compared temperatures in active tunnels (n = 31) to aboveground temperatures during winter (December 2018–February 2019), and to aboveground temperatures during prescribed fire events (n = 16) occurring in spring (March–May 2019). During winter, tunnels provided a more stable thermal environment (average range = 6.5 ± 0.8 C; mean ± se) relative to aboveground (average range = 24.8 ± 1.8 C) temperatures. Similarly, mean tunnel temperature range (2.05 ± 0.5 C) was significantly narrower than aboveground temperature range associated with fire events (497.0 ± 101.4 C). Clearly, tunnels provide a stable thermal environment for pocket gophers and commensals that use their tunnel systems.

As scatterhoarders, Sciurus carolinensis (Eastern Gray Squirrel) usually rely on food they buried during fall to survive cold winter months. However, the range of this species includes areas of the southeastern United States where winter flooding commonly restricts access to buried food during the recovery season. In this study, we investigated the effects of winter flooding on the diet of Eastern Gray Squirrels in bottomland hardwood forests of west-central Alabama. We examined the diet of 42 Eastern Gray Squirrels through DNA analysis of stomach contents collected during fall (September–November) 2016 and winter (December–February) 2015–2016, 2016–2017, and 2018–2019. Eastern Gray Squirrels ate 21 different types of plants, with 6 principal foods (>1% of any squirrel's stomach contents) during fall and 12 principal foods during winter. Throughout both seasons, Juglandaceae (walnut) and Quercus spp. (oak) were the most important foods and together made up 94.1% of the fall diet and an average of 78.6% of the winter diet. In contrast to other studies, we found more varied diets during winter (12 primary foods eaten) than fall (6). Additionally, a majority of the plant types consumed during winter at our study area were not hard-mast plants, and many had not been previously recorded as part of the diet of the Eastern Gray Squirrel. Our results suggest Eastern Gray Squirrels cope with reduced availability of scatterhoarded food due to winter flooding by increasing the diversity of foods they eat to include more herbaceous plants.

Operational-scale forest management experiments are long-term investments because harvest treatment effects may be dynamic throughout one or more rotation lengths. We examined deermouse (Peromyscus spp.) abundance over the first 20 years of the Missouri Ozark Forest Ecosystem Project (MOFEP), which assesses ecological responses to even-aged, uneven-aged, and no-harvest forest management systems applied at landscape scales in the Missouri Ozarks. In the spring of each of 11 sampling years, we sampled Peromyscus populations on two permanent trap grids on each of nine study sites (n = 3 sites per management system). Management entries occurred in 1996 and 2011, with small mammal sampling conducted during two pre-treatment years (1994–1995), and Years 2–5 (1998–2001), Years 13–14 (2009–2010), and Years 16–18 (2012–2014) after the first entry. We estimated abundance for each grid in each sampling year with Bayesian closed-population mark-recapture models, and modeled variation in abundance with negative binomial log-linear mixed effects models. Uneven- and even-aged management systems caused similar increases in Peromyscus abundance that were detectable shortly after the first management entry [proportional effect of even-aged management on Peromyscus abundance vs. no-harvest management: posterior median = 1.8, 95% credible interval 1.0–3.2; proportional effect of uneven-aged vs. no harvest management = 1.7 (1.0, 2.8)]. These effects were not surprising given positive effects of harvest treatments on understory cover and food resources. However, the consistency of this increase was less expected, as we observed no conclusive dissipation of harvest effects even in Years 13–14 after the first entry or amplification of harvest effects after the second entry. Observing extremely high system-wide yearly variation in Peromyscus abundance, we did not detect evidence of increasing divergence in effects of these three management systems or of any area-wide trends in abundance during 1994–2014. However, over subsequent decades, we expect higher potential for divergence in Peromyscus abundance as the three management systems differentially shape forest structure and tree species composition. Thus, the MOFEP study offers a unique framework for building and testing hypotheses about patterns and mechanisms of long-term changes in Ozark forests and effects on vertebrate communities.

Herpetofauna play a critical role in forest ecosystems as key components of biodiversity. Although there have been many studies of forest management impacts on herpetofauna, the majority investigate a small number of species or are limited in spatio-temporal scale. We examined the response of 28 species of herpetofauna to forest management through the Missouri Ozark Forest Ecosystem Project (MOFEP), a long-term, landscape-scale experiment comparing even-age, uneven-age, and no-harvest management strategies. We assessed counts of each species at the local (stand-level) and landscape (compartment-level) scales before and up to 18 years after forest management activities. Four species showed a response at the compartment level; we captured fewer of two species in even-age compartments, more of one species in uneven-age compartments, and fewer of one species in uneven-age compartments. At the stand-level, we documented variable responses to regeneration methods across species and through time. For example, we captured more of all lizard species and some snake species in stands with greater disturbance, such as clearcuts or group openings. For other snakes, salamanders, and toads, we captured more individuals in stands of intermediate disturbance such as intermediate thin and single-tree selection. All lizards exhibited immediate reactions to regeneration methods, but captures subsequently declined through time. Other species, particularly amphibians, took more than a decade to return to pre-treatment capture rates. Overall, it appears that uneven-age and even-age management may enhance herpetofauna diversity at the landscape scale, despite lower counts of some species, when regeneration activities such as clearcutting and single-tree selection occur on a limited and spatially disjunct proportion of each compartment during each management entry. After 23 years of study, even-age, uneven-age, and no-harvest forest management strategies appear sustainable with regard to herpetofauna diversity in the Central Hardwoods region of the United States.

Numerous vertebrate species including Pituophis spp. (pine snakes) and birds of prey have been shown to consume Geomys pinetis (Southeastern Pocket Gopher), but its full spectrum of predators remains undocumented. As a part of a larger project involving radiotracking Southeastern Pocket Gophers in southwestern Georgia, a female Pocket Gopher was consumed by a Crotalus horridus (Timber Rattlesnake) while making an aboveground movement. Timber Rattlesnakes are a previously undocumented predator for Southeastern Pocket Gophers. Our observation further demonstrates predation risks associated with aboveground movement.

Freshwater turtle populations are declining worldwide, yet managers have little information about the effects of commercial turtle harvests. In Missouri, the snapping turtle (Chelydra serpentina), smooth softshell (Apalone mutica), and spiny softshell (Apalone spinifera) are harvested commercially in the Missouri River. In 2011 and 2012, we conducted mark–recapture of these species to estimate abundance on the Missouri River and two unharvested tributaries, the Osage and Gasconade Rivers. We conducted mock harvests, applying capture methods of the state's primary commercial harvester, to estimate plausible expected harvest proportions. Snapping turtle abundance per 2 km was lower at harvested units ( = 15; SE = 7.1; unharvested: = 90; SE = 40.3). Smooth softshell abundance was greater at harvested units ( = 59; SE = 7.9; unharvested: = 14; SE = 28.1), although the difference was not significant. Mean unique spiny softshell captures were similar at harvested ( = 18; SE = 4.3) and unharvested ( = 17; SE = 9.7) units. Expected harvest proportions averaged 23% across species (SE = 5%; range = 6%–79%), exceeding sustainable rates reported for turtles. Our results suggest that on a small scale, using these methods, harvesters can remove a substantial portion of river turtle populations.

During the twentieth century, the North American porcupine (Erethizon dorsatum) was common in the Black Hills of western South Dakota and northeastern Wyoming. However, the low number of recent observations in the region has led to concern that porcupine populations have declined. We conducted systematic surveys to assess porcupine occurrence at two hundred and sixty-three 1-ha sites in the Black Hills National Forest, Custer State Park, Jewel Cave National Monument, Mount Rushmore National Memorial, and Wind Cave National Park during 2016–2017. We observed no porcupines or recent feeding sign. We also noted few recent observations in information compiled from online databases and from other natural resource surveys with which we have been involved in the South Dakota Black Hills. Given the apparent abundance of porcupines in this area in the twentieth century, our results suggest that populations have declined dramatically. Predation by mountain lions (Puma concolor), habitat loss, and human-caused mortality are potential contributing factors, but estimating the degree of population declines and assessing hypotheses about the causes are hindered by a lack of long-term data on the region's porcupine populations. Moreover, accounts of the region's mammalian fauna suggest that porcupines were not abundant in the region during the late 1800s but became common in the early twentieth century.

We evaluated the two-year effects of variable-retention harvest on chipmunk (Tamias spp.) abundance () and habitat in mature coniferous forests in western Oregon and Washington because wildlife responses to density/pattern of retained trees remain largely unknown. In a randomized complete-block design, six treatments were applied to 13-ha units at three sites (blocks): four retention levels of original basal area (BA) in an aggregated tree pattern (100, 75, 40, and 15%) and two retention levels in a dispersed tree pattern (15 and 40%). Log-yarding method differed at each site (suspension cable, shovel-loader, or helicopter). We used an information-theoretic approach to compare six candidate regression models for their ability to predict treatment responses of chipmunk and associated habitat variables. Chipmunk had a positive linear relationship with retention level that predicted a 50% reduction in abundance as % BA retention decreased from 100 to 15% (R2 = 0.36). Disturbed soil cover was strongl...

Human induced land-use change in the form of urbanization and agriculture are rapidly transforming our planet’s terrestrial landscapes and causing the loss of species at unprecedented rates. Studies documenting the impacts of development are extensive; however, less is known about the scale at which species respond to development and specific features of altered landscapes that make them vulnerable. This shortcoming may be due to the difficulty of collecting data across large spatial extents, but filling these information gaps are critical, particularly for species that have a disproportionate influence on ecosystems, such as ecosystem engineers. One such species, the southeastern pocket gopher (Geomys pinetis), has been declining throughout its range (southeastern United States) and continued loss will likely have strong effects on the imperiled longleaf pine ecosystem in which it is closely associated. Using range-wide data from presence-absence surveys and publicly available presence-only data, we used recent advances in species distribution modeling to understand this ecosystem engineer’s associations with extensive land use and cover changes. Our study showed that pocket gophers inhabit a variety of land-use types, including regions with low levels of anthropogenic development, but are largely absent from intensely urbanized areas and closed-canopy forests. Conservation planning to reduce the spread of extensive development and forest management strategies to reduce closed-canopy systems will be instrumental in reducing the decline of the species and ultimately protection of the longleaf pine ecosystem. The approach used in this study will be increasingly beneficial for understanding species response to land-use change.

Understanding movement patterns and their biotic and abiotic correlates is crucial to effectively manage and conserve salamander populations of concern. Because information on Green Salama...

As a non-invasive approach for sampling small mammals, track tubes may be especially useful in species occupancy studies that do not require marking of individuals. However, such studies may involve significant uncertainty in identifying many tracks to species. Using 37 study sites in eastern Alabama and Tennessee, we compared relative differences in detection probabilities with track tubes vs. live traps for Peromyscus (deermice), Oryzomys palustris (Marsh Rice Rat), and Sigmodon hispidus (Hispid Cotton Rat). In analyses that ignored identification uncertainty or that used false-positive occupancy models to address this uncertainty, track tubes and live traps had similar detection probabilities. When uncertain detections were omitted from analysis, effective detectability was lower with track tubes. False-positive occupancy modeling indicated that track-identification uncertainty could not be ignored, as there was a non-zero probability of false-positive detections. False-positive occupancy designs have high relevance to track-tube studies; in addition, such studies should ensure that track identification is done under the oversight of an experienced tracker.

Most of the native shrubsteppe habitat in the northern Columbia Basin of eastern Washington has been invaded by cheatgrass (Bromus tectorum) or converted to agricultural lands. Therefore, ecological patterns and dynamics on native shrubsteppe and reestablished grasslands are of high conservation interest. We analyzed the cheek pouch contents of Great Basin pocket mice (Perognathus parvus) from 48 study sites in this region to quantify seed collection by this species and to determine the influence of habitat type on cheek pouch seed contents. In all 3 habitat types-newly established Conservation Reserve Program (CRP) lands, older CRP lands, and shrubsteppe-B. tectorum constituted the majority of seeds collected from the cheek pouches. Mean generic richness of collected seeds was higher in shrubsteppe than in new CRP habitats. On average, females collected a greater number of seed genera than males did, and pocket mice collected more seed genera as the autumn season progressed. Exotic B. tectorum...

In many regions of the world, forest management has shifted from practices emphasizing timber production to more sustainable harvesting that integrates ecological values, including maintenance of biodiversity, wildlife habitat, and ecological goods and services. To this end, management strategies emphasize retention of stand structures that meet the needs of forest-obligate wildlife species and enhance connectivity across landscapes. However, little is known about the effects on arboreal rodents of varying the amount or spatial distribution of retained structures. We quantified the responses of northern flying squirrels ( Glaucomys sabrinus ) to retention harvests of varying levels (15%, 40%, 75%, and 100% of original basal area) and spatial patterns (trees uniformly dispersed vs. aggregated in 1-ha patches), using six experimental treatments replicated at three locations in southwestern Oregon and Washington. Relative abundance of northern flying squirrels decreased following harvest; minimum number of squirrels known alive (MNKA) in the control (100%) and 75% retention treatment was significantly higher than in the 15% or 40% treatments. In mixed-effects regression models, MNKA increased with treatment-unit basal area and amount of surrounding mature (>80-year-old) forest, suggesting that squirrel abundance was influenced by local structure and landscape-scale variables. However, only basal area contributed to best-fit models of reproductive female abundance. Our results suggest a threshold response of northern flying squirrels to green-tree retention somewhere between 40% and 75% that is likely to be influenced by the spatial pattern of retention and landscape context. This study underscores previous conclusions that northern flying squirrels are sensitive to logging at both local and larger landscape scales, and demonstrates the current minimum retention standard of 15% will not provide suitable habitat for this species.

Postrelease movements can determine the success of wildlife translocations. We monitored movements of 36 captive-reared Ozark Hellbenders (Cryptobranchus alleganiensis bishopi) released to augment wild populations at two sites on the North Fork of the White River (Missouri, USA). We used radiotelemetry to collect 3610 Hellbender locations from May 2008 to August 2009. We quantified movements at multiple spatio-temporal scales and made comparisons between two seasons of monitoring (1 = release–December 2008; 2 = January 2009–August 2009). At the finest (daily) scale, most Hellbenders (90%–94% per season) were highly sedentary (≥50% of observations indicated no movement). Typical distances between daily locations when Hellbenders moved were 20 m between daily locations, and virtually...

Objective evaluations of wildlife reintroductions are vital for increasing the success of future efforts to reestablish endangered species. Attempts to reintroduce one of the most endangered mammals in North America, the black-footed ferret (Mustela nigripes), have been ongoing for 18 years with no quantitative assessment of factors related to reintroduction success. We examined relationships between ferret reintroduction success and factors associated with disease outbreaks, release strategies, and the distribution and abundance of their primary prey, prairie dogs (Cynomys sp.), at 11 reintroduction sites. The most important factor related to ferret reintroduction success was a cumulative metric incorporating both size of the area occupied by prairie dogs and density of prairie dog burrows within that area. Each of the four successful sites had prairie dog populations that occupied an area of at least 4300 ha. No sites with

To sustain native species in managed forests, landowners need silvicultural strategies that retain habitat elements often eliminated during traditional harvests such as clearcut logging. One alternative is green-tree or variable retention. We investigated the response of terrestrial small mammals to experimental harvests that retained large live trees in varying amounts (approximately 100, 75, 40, and 15% of original basal area) and patterns (aggregated versus dispersed) in mature coniferous forests of western Oregon and Washington. Treatments were applied in 36, 13-ha experimental units. We used pitfall traps to sample small mammals for 4 weeks each autumn during 2 years before and 2 years after treatments. We captured 21,351 individuals of 32 species. We analyzed effects of treatments on relative abundance of 12 species. As level of retention declined, we expected species associated with closed-canopy forests to decrease (Sorex trowbridgii, Neurotrichus gibbsii, Peromyscus keeni, Myodes [Clethrionomys] californicus, and M. gapperi); species associated with early successional habitats to increase (S. vagrans, P. maniculatus, Microtus longicaudus, and Microtus oregoni); and habitat generalists to show little response (S. monticolus, S. pacificus, and S. sonomae). As expected, M. californicus declined after harvest, and P. maniculatus and M. longicaudus increased. Sorex sonomae showed an unpredicted decrease. Other species did not show consistent changes. Responses of S. monticolus, S. sonomae, and M. gapperi varied among study areas. For M. gapperi, this variation was not explained by differences in habitat structure among areas. For all species, capture rates were similar in dispersed- and aggregated-retention units. Similarity in species composition between harvested sites and controls decreased with decreasing retention. Future sampling of these treatments is needed to assess long-term responses. Based on our initial results, green-tree retention strategies need to be sensitive to regional variation in environmental characteristics and small mammal community composition.

Understanding herd organization is important when considering management alternatives designed to benefit or manipulate elk (Cervus elaphus) populations. We studied the seasonal and annual herd organization of cow elk in Custer State Park, South Dakota from 1993–1997 by examining seasonal subherd range size, spatial arrangement, overlap, and site fidelity. Based on social interaction analyses, we combined locations of radiocol-lared cow elk to delineate subherds. We computed 95% kernel home ranges with least-squares cross validation for each subherd by season and year. Subherd overlap and fidelity by season and year were computed using the Volume of Intersection Index (VI) statistic. We identified 5 relatively discrete, resident cow–calf subherds. We observed little overlap in utilization distributions of adjacent subherds. The mean VI score across all subherds and time points (n=140) was 0.06 (SE=0.009), indicating an average 6% overlap in subherd area utilization. Subherd overlap between pairs ...

General patterns of small mammal species occurrence across major successional gradients have been studied extensively in western Washington forests, but the effects of smaller-scale disturbances are less clear. Understanding such effects will help to evaluate alternatives to traditional clear-cut logging. We compared relative abundances, population characteristics, and species occurrence of small mammals in experimentally created canopy gaps and adjacent forests in the southern Washington Cascade Range. Contrary to our predictions, species characteristic of closed-canopy conditions dominated captures in all gap sites. No significant declines in abundance between forests and large gap patches were observed for any closed-canopy species. Measures of persistence, reproductive status, sex ratios, and weight distributions did not indicate that gaps were sinks or lower quality habitat for Trowbridge’s shrew (Sorex trowbridgii), Keen’s mouse (Peromyscus keeni), or the southern red-backed vole (Clethrionomys gapperi). The creeping vole (Microtus oregoni) was the only early-successional species to respond strongly to the openings. It occurred frequently in large (0.1–0.2 ha) gaps but rarely in smaller gaps and forested patches. The large gaps targeted in this study are at the upper end of the range of natural gap sizes reported for the western Cascades, but may be too small to provide habitat for most early-successional species. Our results indicated that the main direct effect of disturbance-created small gaps in these areas was to increase resources for forest species rather than to facilitate recruitment of early-successional small mammals.

The natural history of Sorex preblei (Preble's Shrew) and its distribution across western North America are poorly understood. Throughout its range, new records are of high interest (for example, Long and Hoffman 1992; Kirkland and Findley 1996; Hendricks and Roe del 2002; Shohfi and others 2006). Recently, Na gorsen and others (2001) expanded the docu mented distribution of S. preblei to include the Okanagan region of south-central British Co lumbia. Although S. preblei has been captured at numerous locations in eastern Oregon (Verts and Carraway 1998), the only previous records in Washington were from the Blue Mountains (Garfield County) in the southeast corner of the state (Armstrong 1957; Johnson and Cassidy 1997). Nagorsen and others (2001) speculated that the apparent absence of this species in the Columbia Basin of Washington was partially an artifact of insufficient sampling. Here, we re port a record of S. preblei from this gap in its documented distribution.

Recent studies have demonstrated substantial effects of environmental stress that vary among clones. Exposure to ultraviolet radiation (UV) is an important abiotic stressor that is highly variable in aquatic ecosystems due to diel and seasonal variations in incident sunlight as well as to differences in the UV transparency of water among water bodies, the depth distribution of organisms, and the ability of organisms to detect and respond to UV. In contrast to the convention that all UV is damaging, evidence is accumulating for the beneficial effects of exposure to low levels of UV radiation. Whereas UV has been frequently observed as the primary light-related stressor, herein we present evidence that dark conditions may be similarly "stressful" (reduction of overall fitness), and stress responses vary among clones of the freshwater crustacean Daphnia parvula. We have identified a significant relationship between survivorship and reduced fecundity of clones maintained in dark conditions, but no correlation between tolerance of the clones to dark and UV radiation. Low tolerance to dark conditions can have negative effects not only on accumulated stresses in organisms (e.g. the repair of UV-induced damage in organisms with photolyase), but potentially on the overall physiology and fitness of organisms. Our results support recent evidence of the beneficial effects of low-level UV exposure for some organisms.

In the 1930s, the Canada Lynx (Lynx canadensis) was extirpated from Isle Royale, a 535-km2 island located in western Lake Superior, 22 km from the Ontario and Minnesota shorelines. The first half of the 20th century was a time of change on Isle Royale as Caribou (Rangifer tarandus) disappeared, Coyotes (Canis latrans) briefly appeared, Moose (Alces americanus), Grey Wolves (Canis lupus), and Red Foxes (Vulpes vulpes) became established, and the habitat was altered by fire, logging, and over-browsing. Although these changes may have contributed to the demise of the Canada Lynx, our results suggest that over-harvest was a primary cause. Assuming a peak carrying capacity of 75 Canada Lynx and harvest rates comparable to those reported from 1890–1935, a population viability analysis indicated that the island population had a 0% chance of surviving 50 years. The analysis also indicated that, even in the absence of harvest, the population had only a 14% chance of persistence for 250 years. However, when 10 Canada Lynx were added to the modeled population every 10th year, the probability of persistence increased to 100%. Our analyses suggest that the island’s Canada Lynx population maintained itself by periodic immigration across an ice bridge; therefore, natural recolonization should be possible. However, the probability of ice-bridge formation has declined from 0.8 in the winter of 1958–59 to 0.1 in 2012–13, likely as a result of climate change. The Isle Royale situation exemplifies another impact of climate change and the possible need to augment populations to mitigate the loss of connectivity.

Publisher Summary Animal space use and movements are best understood through direct observation. This chapter describes a variety of techniques used to analyze animal space use, including home range estimation, analysis of site fidelity, and animal interactions. It also provides limitations of using many traditional techniques. The chapter provides a discussion of modeling animal movements using a combination of advanced descriptive and visualization approaches, general movement models, and biological models. The importance of sample size and autocorrelation of data in estimating home ranges and animal movements cannot be overemphasized. When considering tradeoffs between sample size and independence, obtaining an adequate sample size is more important than independence between data points. Any analysis of radiotelemetry data must consider the full range of biological and environmental factors that may impact the results. Home range estimation and animal movement analyses must answer difficult questions regarding the internal anatomy of home range boundaries and movement pathways through the judicious use of biological and environmental information. Also, radiotelemetry studies should go beyond simple, general descriptions and use a model-driven approach to examine the key factors determining why and how an animal uses space.

Although bats are a group with high species richness in shrub-steppe areas of the Columbia Basin, limited information is available on distributions, species occurrence, and habitat use. We surveyed bat populations of the Hanford Site, which has provided a refuge for shrub-steppe flora and fauna in Washington State. We used Anabat detectors, harp traps, mist nets, and auditory-visual observations during 1997 and 1998 to document the occurrence of bat species and to compare activity levels among major habitat types on the site. Across both years, we recorded 6,470 bat calls during 302 bat detector survey-nights at 66 locations. Bats of the genus Myotis constituted 84 to 88% of total calls each year. The hoary bat (Lasiurus cinereus), silver-haired bat (Lasionycteris noctivagans), western pipistrelle (Pipistrellus hesperus), big brown bat (Eptesicusfuscus), and pallid bat (Antrozous pallidus) also were recorded. Big brown bats have not been reported previously at the Hanford Site. Detection rates were highest near potential roosting structures and riparian foraging areas, and lowest in upland shrub-steppe cover types. During 133 trap nights across both years, we captured 81 bats of 5 species: the western smallfooted myotis (Myotis ciliolabrum), little brown myotis (M. lucifugus), Yuma myotis (M. yumanensis), silver-haired bat, and pallid bat. The site supports at least 3 arid-land bats (western small-footed myotis, western pipistrelle, and pallid bat) that are near the northern edge of their species distributions. By protecting large patches of undisturbed habitat, the Hanford Site has helped maintain a diverse bat fauna in Washington's shrub-steppe. In addition, some habitat modifications at the site may have benefited bats, as evidenced by heavy use of old buildings, irrigation run-off wetlands, and planted trees.

We tested the validity of a spatially explicit habitat effectiveness model for Rocky Mountain elk (Cervus elaphus nelsoni). The model scored habitat effectiveness based on seasonal changes in the quality, quantity, and availability of forage. Seasonal forage potential scores were derived by integrating information on existing vegetation, site potential, historic disturbances, topography, and roads. The model generated maps of seasonal habitat effectiveness that were used to create utilization distributions (UD; i.e. 3-dimensional density estimates). We tested the elk habitat model using telemetry data collected on 5 cow elk sub-herds from 1993 to 1997 in Custer State Park (CSP), South Dakota, USA. We computed fixed kernel UD from elk telemetry data and simulated random UD within the confines of each sub-herd boundary. The degree of fit between elk UD and model predicted UD (elk-model UD) and random UD and model predicted UD (random-model UD) was represented by sub-herd, season, and year using the Volume of Intersection test statistic (V.I. Index). There were no differences in V.I. Indices by year for elk-model (1993 = 0.59, 1994 = 0.54, 1995 = 0.60, 1996 = 0.57, 1997 = 0.57; F 4,70 = 0.93, P = 0.45) or random-model (1993 = 0.59, 1994 = 0.55, 1995 = 0.59, 1996 = 0.58, 1997 = 0.59; F 4,70 = 1.49, P = 0.21) UD; thus, V.I. Indices were pooled across years. Two-way analysis of variance indicated that elk-model V.I. Indices did not differ by sub-herd (B = 0.50, Y = 0.58, A = 0.56, S = 0.58, R = 0.63; F 4,12 = 2.68, P = 0.08), season (Spring = 0.55, Summer = 0.55, Fall = 0.60, Winter = 0.58; F 3,12 = 0.80, P = 0.52), or the interaction terms (B Spring = 0.48, B Summer = 0.52, B Fall = 0.52, B Winter = 0.49, Y Spring = 0.60, Y Summer = 0.52, Y Fall = 0.58, Y Winter = 0.62, A Spring = 0.47, A Summer = 0.58, A Fall = 0.64, A Winter = 0.54, S Spring = 0.54, S Summer = 0.49, S Fall = 0.64, S Winter = 0.65, R Spring = 0.70, R Summer 0.64, R Fall = 0.60, R Winter = 0.59; F 12,55 = 1.68, P = 0.10). V.I. Indices for random-model UD did not differ by season (Spring = 0.58, Summer = 0.57, Fall = 0.58, Winter = 0.59; F 3,12 = 0.56, P = 0.65) or interaction term (B Spring = 0.55, B Summer = 0.58, B Fall = 0.56, B Winter = 0.54, Y Spring = 0.57, Y Summer = 0.53, Y Fall = 0.53, Y Winter = 0.57, A Spring = 0.61, A Summer = 0.63, A Fall = 0.63, A Winter = 0.64, S Spring = 0.60, S Summer = 0.49, S Fall = 0.57, S Winter = 0.59, R Spring = 0.59, R Summer 0.60, R Fall = 0.60, R Winter = 0.59; F 12,55 = 1.44, P = 0.17); however, differences were noted among sub-herds (B = 0.56, Y = 0.55, A = 0.63, S = 0.56, R = 0.60; F 4,12 = 4.48, P = 0.02). V.I. Indices for elk-model UD differed from random-model UD (F 4,12 = 4.71, P = 0.02); model performance was worse than random (i.e., lower V.I. Indices) for 2 sub-herds (elk-model sub-herd B = 0.50 vs. random-mode sub-herd B = 0.56 and elk-model sub-herd A = 0.56 vs. random-model sub-herd A = 0.63). Lower V.I. Indices were observed for 2 sub-herds that occupied areas recently subjected to large-scale wildfires. For sub-herds not subjected to fire effects (i.e., greater loss of vegetation security cover), the model portrayed elk habitat use less consistently, as represented by greater variability (27-42% larger standard errors) in V.I. Indices, during summer. Conversely, the model portrayed elk habitat use most consistent for the same 3 sub-herds during fall.

bia, Idaho, and Oregon (Watkins 1977; Nagorsen and Brigham 1993; Verts and Carraway 1998). Sarell and McGuinness (1993) presented the first reports of spotted bats in north-central Washington State. Subsequent surveys have noted spotted bats at additional locations, including sites in Douglas, Grant, and Okanogan counties (John Fleckenstein, Natural Heritage Program, Washington Department of Natural Resources, Olympia, WA, pers. comm.; Neal Hedges, Bureau of Land Management, Wenatchee, WA, pers. comm.). However, limited information is available about the distribution

interactions with prey, bears, and humans [dissertation]. Moscow, ID: University of Idaho. 147 p. NOWAK MC. 1999. Predation rates and foraging ecology of adult female mountain lions in northeastern Oregon [thesis]. Pullman, WA: Washington State University. 75 p. Ross IP, JALKOTZY MG. 1996. Cougar predation on moose in southwestern Alberta. Alces 32:1-8. VERTS BJ, CARRAWAY LN. 1998. Land mammals of Oregon. Berkeley, CA: University of California Press. 668 p.