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Mortality causes and survival rates often vary between the geographically disparate populations of a species. Fishers (Pekania pennanti) are a mesocarnivore inhabiting forested areas across Canada and the United States of America. Due to their economic and ecological value, fishers have become the focus of many management and conservation efforts. However, a clear understanding of influential demographic parameters and pressures exerted on disparate populations is necessary for such discussions. We conducted a literature review of peer‐reviewed studies investigating fisher cause‐specific mortalities and survival to (a) synthesize the current available knowledge, (b) assess differences in cause‐specific mortalities and the sex‐specific adult survival rates between western fisher populations (i.e., populations from California, Oregon, Washington, or British Columbia) and eastern fisher populations (i.e., elsewhere in their distribution), and (c) identify potential gaps in the literature. We identified 26 studies between 1994–2024 describing cause‐specific mortality (n = 4), survival rates (n = 15 studies), or both (n = 7), with 20 studies assessing western fisher populations. There were significant differences between the cause‐specific mortalities for fishers in the eastern and western populations. Western fishers had higher mortality from predation and lethal toxicant exposure, while eastern fishers had higher mortality from legal harvest. Survival rates of males and females were not significantly different between the eastern and western populations; however, we found that male survival rates in the western populations varied considerably between studies. The geographic concentration of recent research presents a lack of information regarding the species outside of western populations, which may hinder management efforts throughout their range. Western fisher populations have been the focus of many recent studies and exhibit differences in cause‐specific mortalities but not in survival rates when compared to eastern fisher populations. Western fisher mortalities were dominated by predator attacks while eastern fisher mortalities were dominated by harvest.

ContextMany terrestrial mammals have undergone substantial distribution changes in recent decades; yet collecting broad-scale occurrence data for carnivores is difficult due to their low densities and cryptic behaviors. Carnivore observations from community (i.e., citizen) science programs can be a potentially valuable approach for understanding changes in carnivore distributions over long time periods.ObjectivesWe used 18 years of bobcat (Lynx rufus) observations collected by archery deer hunters (i.e., participants) across Illinois, USA, to estimate spatiotemporal patterns in occurrence and determine how landscape features influenced patterns of recolonization.MethodsWe developed Bayesian spatial and non-spatial multi-scale dynamic occupancy models to estimate county-level occupancy, persistence, and colonization and participant-level occupancy. We modeled county-level parameters as a function of multiple a priori landscape covariates and compared model predictive performance using cross-validation.ResultsOur non-spatial occupancy model had greater predictive support than our spatial occupancy model. Mean annual statewide county-level occupancy increased from approximately 0.43–0.83 while mean annual participant-level occupancy increased from approximately 0.07–0.28. Bobcats were primarily restricted to southern Illinois during the early 2000s but by 2018 occurred throughout western and southern Illinois. Landscape covariates had relatively weak effects on model parameters.ConclusionsOur study illustrates how community science observations analyzed with hierarchical occupancy models can be used to model spatiotemporal changes in species distributions. Bobcats have recolonized much of Illinois, but this colonization was not strongly mediated by county-level landscape features at the scales we measured.

Multiple biotic, abiotic, and evolutionary constraints interact to determine a species’ range. However, most species are not present in all suitable and accessible locations. Dispersal ability may explain why many species do not occupy all suitable habitat, but highly mobile species also exhibit a mismatch. Habitat selection behavior where individuals are site faithful and settle near conspecifics could create a social pressure that make a species’ geographic range resistant to change. We investigated this possibility by using an individual-based model of habitat selection where habitat quality moved each year. Our model demonstrated the benefits of conspecific attraction in relatively stable environments and its detrimental influence when habitat quality shifted rapidly. These results were most apparent when adult survival was high, because site fidelity led to more individuals occupying poor-quality habitat areas as habitat quality changed. These individuals attracted other dispersing individuals, thereby decreasing the ability to track shifts in habitat quality, which we refer to as “social inertia.” Consequently, social inertia may arise for species that exhibit site fidelity and conspecific attraction, which may have conservation implications in light of climate change and widespread alteration of natural habitats.

Interspecific interactions among predators can shape ecological communities across trophic levels, including among predator guilds. The strength and directions of these interactions, however, may vary spatially and temporally in regions undergoing widespread landscape changes (e.g., urbanization, agricultural production). We investigated intraguild effects of coyotes ( Canis latrans ), a de facto apex predator, and land-cover changes on abundance indices of red foxes ( Vulpes vulpes ) and gray foxes ( Urocyon cinereoargenteus ) using two long-term and independent time series: direct observations of canids by archery deer hunters (26 years) and harvest data from canid trappers (41 years) from across Illinois, USA. Abundance indices from both time series for red and gray foxes declined whereas coyote abundance indices increased, suggesting increasing coyote abundance may have led to decreases in fox population abundances. Empirical support among candidate models explaining fox declines was generally equivocal yet differed between fox species. Models including effects of coyote abundance were generally competitive for red foxes and estimated negative coyote effects even after controlling for declining farm size. The empirical support among our landscape hypotheses also varied by species despite increasing forest cover and farm size during our study. The estimated effects of coyote in our study were weaker than reported at more northerly latitudes suggesting that increasing coyote populations may not be fully responsible for observed declines in fox populations in the midwestern USA.

Indices of relative abundance are routinely used to monitor and manage wildlife, yet all indices contain observation error and have unknown relationships with true abundance. State-space models (SSM) allow estimation of observation error while concordance in trends among multiple indices from different sampling methods may reflect true trends in abundance. We used multiple decades of data from roadkill surveys, nocturnal spotlight surveys, and observations from hunters along with trapper harvest data for six mesopredators in Illinois, USA, to evaluate concordance (i.e., similarity in trend direction and magnitude) across count- and harvest-based indices, while controlling for observation error using Bayesian SSM. We assumed that increased concordance among trends from different sampling methods would increasingly mirror trends in true abundance. We observed positive trends for raccoon and coyote, negative trends for gray and red fox, and stable trends for skunk, consistent with spatiotemporal patterns of distribution and abundance of these species within midwestern USA. Concordance among count-based indices and harvest-based indices adjusted for temporal changes in trapper numbers was generally high. In contrast, total annual trapper harvest often showed discordance with other trends. Sampling variability was similar across methods but was highest across the shortest time series highlighting the importance of methodologically or analytically controlling for sampling variability. Our results suggest that concordant broad-scale (e.g., statewide) trends in index data may be best used for evaluating relatively general trends and using relatively drastic changes as justification for more in-depth studies.

Understanding the demographic drivers of range contractions is important for predicting species’ responses to climate change; however, few studies have examined the effects of climate change on survival and recruitment across species’ ranges. We show that climate change can drive trailing edge range contractions through the effects on apparent survival, and potentially recruitment, in a migratory songbird. We assessed the demographic drivers of trailing edge range contractions using a long-term demography dataset for the black-throated blue warbler (Setophaga caerulescens) collected across elevational climate gradients at the trailing edge and core of the breeding range. We used a Bayesian hierarchical model to estimate the effect of climate change on apparent survival and recruitment and to forecast population viability at study plots through 2040. The trailing edge population at the low-elevation plot became locally extinct by 2017. The local population at the mid-elevation plot at the trailing edge gradually declined and is predicted to become extirpated by 2040. Population declines were associated with warming temperatures at the mid-elevation plot, although results were more equivocal at the low-elevation plot where we had fewer years of data. Population density was stable or increasing at the range core, although warming temperatures are predicted to cause population declines by 2040 at the low-elevation plot. This result suggests that even populations within the geographic core of the range are vulnerable to climate change. The demographic drivers of local population declines varied between study plots, but warming temperatures were frequently associated with declining rates of population growth and apparent survival. Declining apparent survival in our study system is likely to be associated with increased adult emigration away from poor-quality habitats. Our results suggest that demographic responses to warming temperatures are complex and dependent on local conditions and geographic range position, but spatial variation in population declines is consistent with the climate-mediated range shift hypothesis. Local populations of black-throated blue warblers near the warm-edge range boundary at low latitudes and low elevations are likely to be the most vulnerable to climate change, potentially leading to local extirpation and range contractions.

An accurate understanding of harvest trends is required for effective wildlife management. Trapper harvest data represent valuable long-term data for evaluating patterns and trends for wildlife species at broad spatiotemporal scales. Inferring accurate trends from harvest data, however, first requires identifying and controlling for confounding factors that vary independent of abundance. We investigated trends in 43 years of trapper harvest data (1976–2018) from Illinois, USA, for red fox (Vulpes vulpes), gray fox (Urocyon cinereoargenteus), and coyote (Canis latrans) while controlling for factors that may affect trapper effort, including number of effective (i.e., successful) trappers, pelt price, gasoline price, winter unemployment, and winter weather conditions. Annual trapper harvest for red and gray foxes declined and was affected by gasoline price and winter unemployment, whereas annual trapper harvest for coyotes increased and was not strongly affected by other covariates. After adjusting for pelt price, harvest of red foxes was relatively stable, but harvest of gray foxes declined and harvest of coyotes increased. Effects of covariates on harvest per successful trapper varied by species; nevertheless, we detected an increasing trend for coyotes and decreasing trends for gray foxes and red foxes. Concordance across indices for gray foxes and coyotes was consistent with hypothesized declines for gray foxes and increases for coyotes in the midwestern United States. Trends for red foxes varied depending on how we accounted for potential confounding factors and it is unclear if these trends suggest population declines or distribution shifts to urban areas with reduced trapping susceptibility. Our results highlight the importance of understanding sources of variation in harvest data and that their effects can vary across species.

Trapping data have a long and rich history of use in monitoring furbearer populations in North America but understanding the influences of variation in trapper harvest is important. Many factors besides abundance can cause variation in trapper harvest, including socioeconomics, weather, and motivation. The relationships between these extrinsic factors and trapper harvest may change temporally, which may obscure the causal understanding of variation in trapper harvest. We tested for changes in the relationships between pelt price and trapper numbers, and pelt price and harvest per trapper for raccoons (Procyon lotor) in Illinois, USA, from 1976–2018 while controlling for other socioeconomic (gasoline price, unemployment) and weather (temp, snow depth) factors. The annual raccoon harvest showed no clear trend, whereas the number of raccoon trappers declined markedly from approximately 1976–1990 in conjunction with pelt prices, after which the number of trappers remained relatively stable and were not significantly affected by pelt price. In contrast, harvest per trapper increased markedly during the 1990s and showed a significant negative relationship with pelt price pre-1990 but a positive relationship post-1990. We propose that declines in pelt prices resulted in a loss of less experienced or economically incentivized trappers, whereas contemporary trappers may continue trapping primarily for non-economic reasons. Our study highlights the potential for using non-linear relationships between trapper harvest data and socioeconomic covariates to help understand the influences of temporal variation in trapper harvest data.

Agricultural intensification has negatively affected biodiversity throughout the world. In the United States, population declines of many early successional bird species have been linked with habitat loss due to agriculture. In light of this, recent efforts have attempted to prioritize conservation actions at continental scales. Importantly, these efforts have used existing data to estimate the global population size for declining species and set future population goals. Though these efforts consider broad scales for conservation efforts and provide population targets, they lack explicit plans to achieve established goals. One way to achieve these population goals is through the process of habitat restoration, such as voluntary private‐land conservation programs that restore habitat in agricultural landscapes and are implemented at a sufficiently large scale to achieve population goals. Our goal was to understand how private‐land conservation programs can be used to achieve population goals for declining species. To do this, we examined the population‐level impacts of the Conservation Reserve Enhancement Program, a program that has created more than 57,000 ha of restored habitat in Illinois, for four declining conservation priority species, the Bell's Vireo (Vireo bellii bellii), Field Sparrow (Spizella pusilla), Northern Bobwhite (Colinus virginianus), and Willow Flycatcher (Empidonax trailli trailli). We surveyed 172 randomly chosen restored fields in 10 counties in central and west‐central Illinois during the 2012–2015 breeding seasons. We found that current private‐land conservation efforts in Illinois are probably effective in achieving state population goals for rare species with restricted habitat preferences such as the Bell's Vireo and may be close to achieving the goal for the Willow Flycatcher. However, more than 10 times the current amount of restored habitat (~1% of land used for agriculture in Illinois) would be required to achieve the population goals set for all of our focal species. Our results suggest that achieving population goals for early successional bird species using land restored through private‐land programs may be possible for some rare species, but the large amount of habitat needed for many species makes achieving these goals only possible with significant increases in private‐land habitat.

Most species are distributed such that their density and occupancy is greatest in one habitat, although they are found in other habitats. For example, a species with a high affinity for forests (its primary habitat) may also use urban areas and shrublands (its alternative habitat), although occupancy of these habitats would be lower. While habitat loss is the main conservation threat for most species, less is known about how changes in primary and alternative habitats impact populations. We used a systematic bird survey of the state of Illinois that spanned the past century to investigate how use of specific habitats was related to population changes. Specifically, we used a hierarchical Bayesian model to investigate the relationship between changes in statewide occupancy (probability a species would occur in a study site) and use of specific habitats (probability a species would be in a specific habitat within our study sites) for 66 species sampled in 1906–1909 and 2006–2008. Changes in the use of alternative habitats, and not primary habitats, was related to overall changes in statewide occupancy. Many species that increased over the past century did so by increasing their use of urban areas, while declining species declined the most in agricultural and grassland areas. Although primary habitats form the core of a species' distribution, alternative habitats may provide opportunities for a species to expand its distribution; conversely, declining species may abandon alternative habitats and contract into primary habitats. Consequently, alternative habitats may play an important role in the future of many species. Understanding this role could be crucial for successful conservation.