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Context Many prey species exhibit antipredator behaviours when threatened, yet prey response to temporal variation in predation risk is not well-understood, despite being foundational to predator–prey dynamics and an important consideration among game population managers and recreationalists. Aims To examine white-tailed deer (Odocoileus virginianus) behaviour in response to temporal variation in predation risk imposed by recreational hunters and to assess the effect of deer sex and age on antipredator response. Methods Global positioning system (GPS) collars were used to monitor behaviour of female and male deer in response to diel and weekly patterns of recreational hunting in Alabama, USA. Key results Deer behaviour on weekends (i.e. Friday–Sunday), corresponding to periods of elevated risk, was similar to behaviour on weekdays (i.e. Monday–Thursday). However, when behaviour was examined by individual day of the week, movement rate decreased by 17%, net displacement decreased by 31%, and the probability of activity decreased by 24% during daylight hours on Sundays compared with Fridays. Behavioural changes among days were not detected at night. Daytime behavioural shifts persisted until Wednesdays, despite lower weekday hunting activity. Behavioural variation by deer sex and age was also observed. Conclusions Deer perceive temporal variation in predation risk and modify their behaviour to reduce the likelihood of predation. Variation in response across sex and age classes may be driven by previous experience with hunters and/or survival- and fitness-related trade-offs that affect prey decisions at the individual level. Antipredator response was not initially detectable when examined at a broad temporal scale (i.e. weekend vs weekday); however, a behavioural response was shown with a finer-scale analysis (i.e. individual day of the week), which more closely reflected the pattern of risk fluctuation. Implications Our findings demonstrated the acute awareness of a large ungulate to temporal changes in predation risk and provided insight into ways in which these prey behaviourally respond to reduce the likelihood of predatory encounters. Future studies should consider the temporal scale of risk fluctuation when examining antipredator response to avoid false conclusions. Ungulate hunters and managers can use this information to more efficiently achieve their goals.

Pocket gophers provide vital ecosystem services; however, species like the southeastern pocket gopher (Geomys pinetis), endemic to the southeastern United States, are declining. Long-term conservation of this species requires greater understanding of its habitat characteristics. Our objective here was to determine habitat features associated with southeastern pocket gopher occurrence at the local (100 ha) and home-range (0.09 ha) scales. We assessed occurrence and carried out vegetation surveys at 177 sites across the species’ range during the growing season (March–September) 2016–2017. At the local scale, we found a negative relationship between occurrence and groundcover height and a quadratic relationship with canopy closure. At the home-range scale, occurrence was positively related to grass groundcover and had a quadratic relationship with canopy closure. Restoration of southeastern pocket gopher habitat should focus on creating or maintaining areas with intermediate canopy (~45–55%) and an understory dominated by grasses and forbs.

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.

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.

Modern forest management seeks to balance multiple social, economic, and ecological goals. Different management approaches create different types of disturbances in a forest ecosystem and thus also differ in their impacts on plants, animals, and insects. Understanding these impacts is important for conservation of forest ecosystem function, but challenging due to the large spatial and temporal scale over which management occurs. Most past research has focused on relatively small areas, short time scales, and/or a small number of species. To address this, we examined the effects of two common silvicultural systems (even and uneven aged) on abundance and richness of three vertebrate taxa (birds, small mammals, and herpetofauna) over a two-decade period in a temperate hardwood forest in Missouri, USA. The two systems removed a similar amount of biomass overall, but differed in the intensity, number, and configuration of harvests applied. We found that vertebrate population responses varied by taxa, occurred at multiple spatial scales, and were concentrated in the period following the first harvest entry. Birds generally had the largest changes in relative abundance, both positive and negative, following management. Small mammals and reptiles had smaller, but generally positive, responses; amphibians were mixed. Bird species tended to respond in the same way to both silvicultural systems, while small mammals and herpetofauna did not respond consistently. Thus, for birds, the total amount of harvest disturbance across the landscape drives population responses, while for others the size and configuration of individual harvests is likely more important. Synthesizing results across the vertebrate community at large spatial and temporal scales allows managers to better understand trade-offs when making decisions that will affect wildlife in contrasting ways.

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

We used a stochastic Leslie matrix model parameterized with demographic data from Wind Cave National Park to evaluate effects of four culling strategies on population growth rates and age and sex structure of bison (Bison bison Linnaeus). The four culling scenarios we modeled included removal of: (1) yearlings only; (2) calf/cow combination; (3) a herd-wide proportional cull (i.e., individuals taken in proportion to their availability); and (4) calves only. We also allowed either one, two, or three years to elapse between culls to mimic current management activities, and chose culling values for each scenario that would maintain a stable population (i.e., λ ≈ 1.00). In the absence of culling, our model projected a growth rate of 16% per year (λ= 1.16) (SD = 0.02) for the Wind Cave bison population. The modeled population was characterized by a unimodal age structure for bulls and cows and a 1:1 bull: cow ratio. Removal of 75% of the yearlings or 75% of the calves every year was needed to maintain...

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.

Wildlife resource selection studies typically compare used to available resources; selection or avoidance occurs when use is disproportionately greater or less than availability. Comparing used to available resources is problematic because results are often greatly influenced by what is considered available to the animal. Moreover, placing relocation points within resource units is often difficult due to radiotelemetry and mapping errors. Given these problems, we suggest that an animal’s resource use be summarized at the scale of the home range (i.e., the spatial distribution of all point locations of an animal) rather than by individual points that are considered used or available. To account for differences in use-intensity throughout an animal’s home range, we model resource selection using kernel density estimates and polytomous logistic regression. We present a case study of elk (Cervus elaphus) resource selection in South Dakota to illustrate the procedure. There are several advantages of our proposed approach. First, resource availability goes undefined by the investigator, which is a difficult and often arbitrary decision. Instead, the technique compares the intensity of animal use throughout the home range. This technique also avoids problems with classifying locations rigidly as used or unused. Second, location coordinates do not need to be placed within mapped resource units, which is problematic given mapping and telemetry error. Finally, resource use is considered at an appropriate scale for management because most wildlife resource decisions are made at the level of the patch. Despite the advantages of this use-intensity procedure, future research should address spatial autocorrelation and develop spatial models for ordered categorical variables.

In studies of animal space use, researchers often use kernel-based techniques for estimating the size of an animal's home range and its utilization distribution from radiotracking data. However, the kernel estimator is highly sensitive to the bandwidth value used. Previous ecological studies recommended least-squares cross-validation (LSCV) as the default bandwidth selection method, but some statisticians consider this technique inferior to newer methods. We used simulations to compare the performance of the scaling LSCV and reference approaches to plug-in and solve-the-equation (STE) bandwidth methods. We generated samples of 20, 50, and 150 points from mixtures of 2, 4, and 16 bivariate normal distributions. We selected the ranges of potential variances for these distributions to create 4 distribution types with varied levels of clumping to simulate the diversity of location patterns expected from radiotracking data. For most distribution types, plug-in and STE methods performed as well or better than LSCV in % absolute error of home-range size estimates and overlap of estimated and true utilization distributions. Although the relative differences usually were small, the plug-in and STE approaches provide good alternatives to LSCV. However, LSCV performed better with distribution types composed entirely of tight clumps of points. The reference bandwidth performed poorly for most distributions. Surprisingly, it often had the lowest absolute error at outer contours for distributions consisting of a single very tight cluster surrounded by more dispersed points. Although our results demonstrate the utility of plug-in and STE approaches, no method was best across all distributions. Rather, choice of a bandwidth selection method may vary depending on the study goals, sample size, and patterns of space use by the study species. In general, we recommend plug-in and STE approaches for estimating relatively smooth outer contours. The LSCV approach is better at identifying tight clumps, including areas of peak use, although risk of LSCV failure also increases when a distribution has a very tight cluster of points. When planning to use kernel methods, researchers should consider these factors to make preliminary decisions about the bandwidth method expected to be most appropriate in their study.

Often resource selection functions (RSFs) are developed by comparing resource attributes of used sites to unused or available ones. We present alternative approaches to the analysis of resource selection based on the utilization distribution (UD). Our objectives are to describe the rationale for estimation of RSFs based on UDs, offer advice about computing UDs and RSFs, and illustrate their use in resource selection studies. We discuss the 3 main factors that should be considered when using kernel UD-based estimates of space use: selection of bandwidth values, sample size versus precision of estimates, and UD shape and complexity. We present 3 case studies that demonstrate use of UDs in resource selection modeling. The first example demonstrates the general case of RSF estimation that uses multiple regression adjusted for spatial autocorrelation to relate UD estimates (i.e., the probability density function) to resource attributes. A second example, involving Poisson regression with an offset term, is presented as an alternative for modeling the relative frequency, or probability of use, within defined habitat units. This procedure uses the relative frequency of locations within a habitat unit as a surrogate of the UD and requires relatively fewer user-defined options in the modeling of resource selection. Last, we illustrate how the UD can also be used to enhance univariate resource selection analyses, such as compositional analysis, in cases where animals use their range nonrandomly. The UD helps overcome several common shortcomings of some other analytical techniques by treating the animal as the primary sampling unit, summarizing use in a continuous and probabilistic manner, and relying on the pattern of animal space use rather than using individual sampling points. However, several drawbacks are apparent when using the UD in resource selection analyses. Choice of UD estimator is important and sensitive to sample size and user-defined options, such as bandwidth and software selection. Extensions to these procedures could consider behavioral-based approaches and alternative techniques to estimate the UD directly.

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 ...

The degree of space-use overlap among adjacent individuals is a central focus of many wildlife investigations. We studied the comparability of minimum convex polygon and fixed-kernel home-range overlap indices and Volume of Intersection (VI) scores using simulated data. We simulated pairs of point patterns to represent telemetry locations of adjacent individuals and varied the amount of potential overlap in the simulation region (100%, 50%, and 10%) and the point distribution (random, loosely clumped, and tightly clumped). We created 1,000 pairs of point sets (60 points in each individual set) for each of the 9 potential overlap and point distribution combinations. In all 9 treatment combinations, VI scores were highest followed by kernel and then polygon estimates. Raw differences among estimates within a treatment were greatest when there was 50% potential overlap, and overlap indices decreased as the degree of clumping increased. The relative differences among overlap indices within a treatment were affected most by potential overlap; differences generally were greatest at 10% and least at 100%. Correlation between index values was lowest for random point patterns, and highest for loosely clumped and tightly clumped point patterns. Although the VI tended to indicate the most overlap and minimum convex polygon the least, there was no consistent correction factor among techniques because of the interacting effects of the overlap index, distribution pattern, and potential overlap. Interpretation of overlap measures requires careful consideration of assumptions and properties of animals under study.

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.

List of contributors Foreword Preface Acknowledgements Part I. Overview: 1. Ecological monitoring: the heart of the matter Robert A. Gitzen and Joshua J. Millspaugh 2. An overview of statistical considerations in long-term monitoring Joel H. Reynolds 3. Monitoring (that) matters Douglas H. Johnson 4. Maximizing the utility of monitoring to the adaptive management of natural resources William L. Kendall and Clinton T. Moore Part II. Survey Design: 5. Spatial sampling designs for long-term ecological monitoring Trent McDonald 6. Spatially balanced survey designs for natural resources Anthony R. Olsen, Thomas M. Kincaid and Quinn Payton 7. The role of monitoring design in detecting trend in long-term ecological monitoring studies N. Scott Urquhart 8. Estimating variance components and related parameters when planning long-term monitoring programs John R. Skalski 9. Variance components estimation for continuous and discrete data, with emphasis on cross-classified sampling designs Brian R. Gray 10. Simulating future uncertainty to guide the selection of survey designs for long-term monitoring Steven L. Garman, E. William Schweiger and Daniel J. Manier Part III. Data Analysis: 11. Analysis options for estimating status and trends in long-term monitoring Jonathan Bart and Hawthorne L. Beyer 12. Analytical options for estimating ecological thresholds - statistical considerations Song S. Qian 13. The treatment of missing data in long-term monitoring programs Douglas H. Johnson and Michael B. Soma 14. Survey analysis in natural resource monitoring programs with a focus on cumulative distribution functions Thomas M. Kincaid and Anthony R. Olsen 15. Structural equation modeling and the analysis of long-term monitoring data James B. Grace, Jon E. Keeley, Darren J. Johnson and Kenneth A. Bollen Part IV. Advanced Issues and Applications: 16. GRTS and graphs: monitoring natural resources in urban landscapes Todd R. Lookingbill, John Paul Schmit and Shawn L. Carter 17. Incorporating predicted species distribution in adaptive and conventional sampling designs David R. Smith, Lei Yuancai, Christopher A. Walter and John A. Young 18. Study design and analysis options for demographic and species occurrence dynamics Darryl I. MacKenzie 19. Dealing with incomplete and variable detectability in multi-year, multi-site monitoring of ecological populations Sarah J. Converse and J. Andrew Royle 20. Optimal spatio-temporal monitoring designs for characterizing population trends Mevin B. Hooten, Beth E. Ross and Christopher K. Wikle 21. Use of citizen-science monitoring for pattern discovery and biological inference Wesley M. Hochachka, Daniel Fink and Benjamin Zuckerberg Part V. Conclusion: 22. Institutionalizing an effective long-term monitoring program in the US National Park Service Steven G. Fancy and Robert E. Bennetts 23. Choosing among long-term ecological monitoring programs and knowing when to stop Hugh P. Possingham, Richard A. Fuller and Liana N. Joseph References Index.

A model is a formal framework for organizing and synthesizing existing knowledge about an ecological system. Models have become pervasive tools in natural resources management, large-scale planning, and landscape ecology. Models help address fundamental questions about wildlife habitat relationships and habitat management. Landscape models take many forms, including statistical models that quantify relationships and patterns among variables conceptual models that offer a qualitative construct of a system, and simulation models that project landscape features into the future. Landscape models can produce output that is as difficult to analyze and understand as data from the original system. For examining and presenting the results from landscape simulation models, ecologists need tools that facilitate interpretation of complex multivariate patterns. There are multiple potential purposes for formalizing one's intellectual framework into a model, whether conceptual or quantitative. Regardless of whether one constructs a landscape simulation model or draws a diagram on the back of a napkin, constructing a model forces biologists to confront their assumptions about the system and the support for these assumptions. A management-oriented model is built to help managers determine the course of action to take, the risks associated with alternative actions, and the uncertainties that must be addressed to make better decisions.