Reintroduction of Fish and Wildlife Populationsprovides a practical step-by-step guide to successfully planning, implementing, and evaluating the reestablishment of animal populations in former ...habitats or their introduction in new environments. In each chapter, experts in reintroduction biology outline a comprehensive synthesis of core concepts, issues, techniques, and perspectives. This manual and reference supports scientists and managers from fisheries and wildlife professions as they plan reintroductions, initiate releases of individuals, and manage restored populations over time. Covering a broad range of taxonomic groups, ecosystems, and global regions, this edited volume is an essential guide for academics, students, and professionals in natural resource management.
1. Predators affect prey by killing them directly (lethal effects) and by inducing costly antipredator behaviours in living prey (risk effects). Risk effects can strongly influence prey populations ...and cascade through trophic systems. A prerequisite for assessing risk effects is characterizing the spatiotemporal variation in predation risk. 2. Risk effects research has experienced rapid growth in the last several decades. However, preliminary assessments of the resultant literature suggest that researchers characterize prédation risk using a variety of techniques. The implications of this methodological variation for inference and comparability among studies have not been well recognized or formally synthesized. 3. We couple a literature survey with a hierarchical framework, developed from established theory, to quantify the methodological variation in characterizing risk using carnivore-ungulate systems as a case study. Via this process, we documented 244 metrics of risk from 141 studies falling into at least 13 distinct subcategories within three broader categories. 4. Both empirical and theoretical work suggest risk and its effects on prey constitute a complex, multi-dimensional process with expressions varying by spatiotemporal scale. Our survey suggests this multi-scale complexity is reflected in the literature as a whole but often underappreciated in any given study, which complicates comparability among studies and leads to an overemphasis on documenting the presence of risk effects rather than their mechanisms or scale of influence. 5. We suggest risk metrics be placed in a more concrete conceptual framework to clarify inference surrounding risk effects and their cascading effects throughout ecosystems. We recommend studies (i) take a multi-scale approach to characterizing risk; (ii) explicitly consider 'true' predation risk (probability of prédation per unit time); and (iii) use risk metrics that facilitate comparison among studies and the evaluation of multiple competing hypotheses. Addressing the pressing questions in risk effects research, including how, to what extent and on what scale they occur, requires leveraging the advantages of the many methods available to characterize risk while minimizing the confusion caused by variability in their application.
Physiological stress responses allow individuals to adapt to changes in their status or surroundings, but chronic exposure to stressors could have detrimental effects. Increased stress hormone ...secretion leads to short-term escape behavior; however, no studies have assessed the potential of longer-term escape behavior, when individuals are in a chronic physiological state. Such refuge behavior is likely to take two forms, where an individual or population restricts its space use patterns spatially (spatial refuge hypothesis), or alters its use of space temporally (temporal refuge hypothesis). We tested the spatial and temporal refuge hypotheses by comparing space use patterns among three African elephant populations maintaining different fecal glucocorticoid metabolite (FGM) concentrations. In support of the spatial refuge hypothesis, the elephant population that maintained elevated FGM concentrations (iSimangaliso) used 20% less of its reserve than did an elephant population with lower FGM concentrations (Pilanesberg) in a reserve of similar size, and 43% less than elephants in the smaller Phinda reserve. We found mixed support for the temporal refuge hypothesis; home range sizes in the iSimangaliso population did not differ by day compared to nighttime, but elephants used areas within their home ranges differently between day and night. Elephants in all three reserves generally selected forest and woodland habitats over grasslands, but elephants in iSimangaliso selected exotic forest plantations over native habitat types. Our findings suggest that chronic stress is associated with restricted space use and altered habitat preferences that resemble a facultative refuge behavioral response. Elephants can maintain elevated FGM levels for ≥ 6 years following translocation, during which they exhibit refuge behavior that is likely a result of human disturbance and habitat conditions. Wildlife managers planning to translocate animals, or to initiate other management activities that could result in chronic stress responses, should consider the potential for, and consequences of, refuge behavior.
Fecal glucocorticoid metabolite analyses are increasingly being used by a variety of scientists (e.g., conservation biologists, animal scientists) to examine glucocorticoid (i.e., stress hormone) ...secretion in domestic and wild vertebrates. Adrenocortical activity (i.e., stress response) is of interest to conservation biologists because stress can alter animal behavior, reduce resistance to disease, and affect population performance. The noninvasiveness of fecal-based assessments is attractive, particularly when studying endangered species, because samples can often be obtained without disturbing the animal. Despite such advantages, many confounding factors inhibit the utility of this technique in addressing conservation problems. In particular, interpretation of fecal glucocorticoid metabolite (FGM) measures may be confounded by the length of time animals are held in captivity, normal seasonal and daily rhythms, body condition, sample storage and treatment techniques, diet of the animal, assay selection, animal status (i.e., social ranking, reproductive status), sample age and condition, and sample mass. Further complicating interpretation and utility of these measures is the apparent species-specific response to these factors. The purpose of this paper is to discuss the factors that confound interpretation of FGM measures, summarize research that addresses these issues, and offer an agenda for future research and interpretation. We urge conservation biologists to carefully consider confounding factors and the relationship between FGM secretion and population performance and biological costs when investigating effects of environmental and human-induced disturbances on wildlife. The crisis nature of many decisions in conservation biology often requires decisions from limited data; however, confirmatory results should not be posited when data are incomplete or confounding factors are not understood. Building reliable databases, and research with surrogate species when possible, will aid future efforts and enhance the utility of FGM assays.
Urbanization often results in biodiversity loss and homogenization, but this result is not universal and there is substantial variability in the spatiotemporal effects of urbanization on wildlife ...across cities and taxa. Areas with lower population and housing density are some of the fastest-growing regions in the western United States; thus, more research in these areas could offer additional insight into the effects of urbanization on wildlife and the potential importance of wild spaces in maintaining a diverse biotic community surrounding developed areas. To address this need, we conducted a study to identify the effects of urbanization (i.e. housing density) on mammals along a housing density gradient from wilderness to suburbia in Missoula, Montana. We deployed 178 motion-activated trail cameras at random sites within urban/suburban, exurban, rural, and wild regions from May to October 2019 to 2020. We identified all mammals >150 g, then evaluated how housing density influenced: (i) occupancy and (ii) species richness using multispecies occupancy models; (iii) relative abundance using Poisson models; and (iv) diel activity patterns using kernel density estimation and logistic regression. Urbanization was the strongest driver of mammal distribution, with a linear decline in mammal species richness as housing density increased. Urbanization also had strong effects on occupancy and detection rates, with larger-bodied mammals generally having stronger negative associations. Overall, mammal relative abundance was highest in suburban regions; however, this effect was largely driven by White-tailed Deer. Natural environmental factors explained most changes in mammal nocturnal activity; however, urbanization strongly affected nocturnality in some species, with Black Bear and White-tailed Deer becoming more nocturnal and Red Fox and Northern Raccoon becoming less nocturnal as housing density increased. While our study confirms that some mammals can live and thrive in developed areas, it emphasizes the importance of maintaining wild areas for those species that cannot.
Developed areas are thought to have low species diversity, low animal abundance, few native predators, and thus low resilience and ecological function. Working with citizen scientist volunteers to ...survey mammals at 1427 sites across two development gradients (wild-rural-exurban-suburban-urban) and four plot types (large forests, small forest fragments, open areas and residential yards) in the eastern US, we show that developed areas actually had significantly higher or statistically similar mammalian occupancy, relative abundance, richness and diversity compared to wild areas. However, although some animals can thrive in suburbia, conservation of wild areas and preservation of green space within cities are needed to protect sensitive species and to give all species the chance to adapt and persist in the Anthropocene.
Camera trapping is a powerful tool for studying mammal populations over large spatial scales. Density estimation using camera-trap data is a commonly desired outcome, but most approaches only work ...for species that can be individually recognized, and researchers studying most mammals are typically constrained to measures of site occupancy or detection rate. These 2 metrics are often used as measures of relative abundance and presumed to be related directly to animal density. To test this relationship, we estimated density, occupancy, and detection rate of male white-tailed deer (Odocoileus virginianus) using camera-trap data collected from 1,199 cameras across 20 study sites. Detection rate and density exhibited stronger positive linear correlation (r2 = 0.80) than occupancy and density (r2 = 0.27). When hunted and unhunted paired areas were compared, detection rate and density showed the same trend between paired sites 62.5% of the time compared to 87.5% for occupancy and density. In particular, agreement between estimates was lowest for pairs of sites that had the largest differences in surrounding housing density. Although it is clear occupancy and detection rate contain some information about density, models suggested different ecological relationships associated with the metrics. Using occupancy or detection rate as proxies for density may be particularly problematic when comparing between areas where animals might to move or behave differently, such as urban–wild interfaces. In such cases, alternate methods of density approximation are recommended.
Extensive research has demonstrated that urbanization strongly alters ecological processes, often perniciously. However, quantifying the magnitude of urban effects and determining how generalized ...they can be across systems depends on the ways in which urbanization is measured and modelled.
We coupled a formal literature survey with a novel conceptual framework to document and synthesize the myriad of metrics used to quantify urbanization. The framework enables clear cataloguing of urban metrics by identifying (a) the urban component measured, (b) the method of measurement, (c) the metric's spatial scale and (d) the metric's temporal nature. Thus, the framework comprehensively captures the what, how, where and when of urban metrics.
We documented striking variability in urban metrics with respect to which urban components were measured as well as how, where and when they were quantified. Overall, our survey revealed that they tended to be: (a) structurally focused, (b) methodologically simplistic, (c) spatially variable and (d) temporally static.
Synthesis and applications. Many metrics are used to quantify urbanization or ‘urban‐ness'. The variation in urban metrics complicates the development of theory, comparisons of findings across studies, and the implementation of management and conservation actions. To pave a clear path forward for more efficient and policy‐relevant urban research, we systematically organized urban metrics using a simple, flexible and comprehensive framework. The framework clarifies what urbanization actually means in empirical practice and identifies several crucial areas for future research, including: (a) systematic assessments of urban metrics across multiple scales, (b) an increased and judicious use of more complex urban metrics aimed at evaluating both mechanistic and broad‐scale correlative ecological hypotheses, and (c) an increased emphasis on the socio‐economic aspects of urban effects.
Many metrics are used to quantify urbanization or ‘urban‐ness'. The variation in urban metrics complicates the development of theory, comparisons of findings across studies, and the implementation of management and conservation actions. To pave a clear path forward for more efficient and policy‐relevant urban research, we systematically organized urban metrics using a simple, flexible and comprehensive framework. The framework clarifies what urbanization actually means in empirical practice and identifies several crucial areas for future research, including: (a) systematic assessments of urban metrics across multiple scales, (b) an increased and judicious use of more complex urban metrics aimed at evaluating both mechanistic and broad‐scale correlative ecological hypotheses, and (c) an increased emphasis on the socio‐economic aspects of urban effects.
In the first 2 decades of the twenty‐first century, American black bear (Ursus americanus) populations rebounded with range expansions into areas where the species was previously extirpated. While ...there are a number of factors that limit range expansion, habitat quality and availability are among the most important. Such factors may be particularly important in western Nevada, USA, at the transition zone of the Sierra Nevada and the Great Basin Desert. We deployed a multi‐faceted data collection system including motion‐sensitive cameras, noninvasive hair sampling and genotyping, and global positioning system (GPS) tracking. We analyzed data using spatial capture‐recapture to estimate population density and dynamic occupancy models to estimate habitat use. Black bear habitat use and density were substantially higher in the Sierra Nevada than the Great Basin Desert and had strong positive relationships with the presence of conifer land cover in the transition zone. The average black bear density was >4 times higher in the mixed‐conifer forests of the Sierra Nevada (12.4 bears/100 km2) than in desert mountain ranges with piñon (Pinus monophylla)‐juniper (Juniperus spp.) woodland (2.7 bears/100 km2). The low‐elevation shrub and grassland portions of the study area had even lower estimated black bear density (0.6 bears/100 km2) and probability of use (0.03, 95% CI = 0.00–0.09). Across these spatially variable configurations in black bear density, we estimated the population size to be 418 individuals (95% CI = 239–740). Declining density towards the range edge, coupled with a relatively stable range of black bears in Nevada observed since 2000, suggests that further species range expansion into the western Great Basin may be limited by habitat quality and availability.
Black bears are at the edge of their range in the western Great Basin in Nevada. We estimated that black bear density was 4 times lower in piñon‐juniper woodland in the Great Basin compared to mixed conifer in the nearby Sierra Nevada. Low densities in piñon‐juniper woodland may limit black bear range in the Great Basin.
1. Managed public wild areas have dual mandates to protect biodiversity and provide recreational opportunities for people. These goals could be at odds if recreation, ranging from hiking to legal ...hunting, disrupts wildlife enough to alter their space use or community structure. 2. We evaluated the effect of managed hunting and recreation on 12 terrestrial wildlife species by employing a large citizen science camera trapping survey at 1947 sites stratified across different levels of human activities in 32 protected forests in the eastern USA. 3. Habitat covariates, especially the amount of large continuous forest and local housing density, were more important than recreation for affecting the distribution of most species. The four most hunted species (white-tailed deer, raccoons, eastern grey and fox squirrels) were commonly detected throughout the region, but relatively less so at hunted sites. Recreation was most important for affecting the distribution of coyotes, which used hunted areas more compared with unhunted control areas, and did not avoid areas used by hikers. 4. Most species did not avoid human-made trails, and many predators positively selected them. Bears and bobcats were more likely to avoid people in hunted areas than unhunted preserves, suggesting that they perceive the risk of humans differently depending on local hunting regulations. However, this effect was not found for the most heavily hunted species, suggesting that human hunters are not broadly creating 'fear' effects to the wildlife community as would be expected for apex predators. 5. Synthesis and applications. Although we found that hiking and managed hunting have measureable effects on the distribution of some species, these were relatively minor in comparison with the importance of habitat covariates associated with land use and habitat fragmentation. These patterns of wildlife distribution suggest that the present practices for regulating recreation in the region are sustainable and in balance with the goal of protecting wildlife populations and may be facilitated by decades of animal habituation to humans. The citizen science monitoring approach we developed could offer a long-term monitoring protocol for protected areas, which would help managers to detect where and when the balance between recreation and wildlife has tipped.
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