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Seasonal variation in habitat use and animal behavior can alter host contact patterns with potential consequences for pathogen transmission dynamics. The endangered Florida panther (Puma concolor coryi) has experienced significant pathogen-induced mortality and continues to be at risk of future epidemics. Prior research has found increased panther movement in Florida's dry versus wet seasons, which may affect panther population connectivity and seasonally increase potential pathogen transmission. Our objective was to determine if Florida panthers are more spatially connected in dry seasons relative to wet seasons, and test if identified connectivity differences resulted in divergent predicted epidemic dynamics. We leveraged extensive panther telemetry data to construct seasonal panther home range overlap networks over an 11 year period. We tested for differences in network connectivity, and used observed network characteristics to simulate transmission of a broad range of pathogens through dry and wet season networks. We found that panthers were more spatially connected in dry seasons than wet seasons. Further, these differences resulted in a trend toward larger and longer pathogen outbreaks when epidemics were initiated in the dry season. Our results demonstrate that seasonal variation in behavioral patterns—even among largely solitary species—can have substantial impacts on epidemic dynamics. [ABSTRACT FROM AUTHOR]

Seasonal variation in habitat use and animal behavior can alter host contact patterns with potential consequences for pathogen transmission dynamics. The endangered Florida panther (Puma concolor coryi) has experienced significant pathogen-induced mortality and continues to be at risk of future epidemics. Prior research has found increased panther movement in Florida's dry versus wet seasons, which may affect panther population connectivity and seasonally increase potential pathogen transmission. Our objective was to determine if Florida panthers are more spatially connected in dry seasons relative to wet seasons, and test if identified connectivity differences resulted in divergent predicted epidemic dynamics. We leveraged extensive panther telemetry data to construct seasonal panther home range overlap networks over an 11 year period. We tested for differences in network connectivity, and used observed network characteristics to simulate transmission of a broad range of pathogens through dry and wet season networks. We found that panthers were more spatially connected in dry seasons than wet seasons. Further, these differences resulted in a trend toward larger and longer pathogen outbreaks when epidemics were initiated in the dry season. Our results demonstrate that seasonal variation in behavioral patterns—even among largely solitary species—can have substantial impacts on epidemic dynamics. [ABSTRACT FROM AUTHOR]

Seasonal variation in habitat use and animal behavior can alter host contact patterns with potential consequences for pathogen transmission dynamics. The endangered Florida panther (Puma concolor coryi) has experienced significant pathogen-induced mortality and continues to be at risk of future epidemics. Prior research has found increased panther movement in Florida's dry versus wet seasons, which may affect panther population connectivity and seasonally increase potential pathogen transmission. Our objective was to determine if Florida panthers are more spatially connected in dry seasons relative to wet seasons, and test if identified connectivity differences resulted in divergent predicted epidemic dynamics. We leveraged extensive panther telemetry data to construct seasonal panther home range overlap networks over an 11 year period. We tested for differences in network connectivity, and used observed network characteristics to simulate transmission of a broad range of pathogens through dry and wet season networks. We found that panthers were more spatially connected in dry seasons than wet seasons. Further, these differences resulted in a trend toward larger and longer pathogen outbreaks when epidemics were initiated in the dry season. Our results demonstrate that seasonal variation in behavioral patterns—even among largely solitary species—can have substantial impacts on epidemic dynamics. [ABSTRACT FROM AUTHOR]

The phylogeography of the American black bear (Ursus americanus) is characterized by isolation into glacial refugia, followed by population expansion and genetic admixture. Anthropogenic activities, including overharvest, habitat loss, and transportation infrastructure, have also influenced their landscape genetic structure. We describe the genetic structure of the American black bear in the American Southwest and northern Mexico and investigate how prehistoric and contemporary forces shaped genetic structure and influenced gene flow. Using a suite of microsatellites and a sample of 550 bears, we identified 14 subpopulations organized hierarchically following the distribution of ecoregions and mountain ranges containing black bear habitat. The pattern of subdivision we observed is more likely a product of postglacial habitat fragmentation during the Pleistocene and Holocene, rather than a consequence of contemporary anthropogenic barriers to movement during the Anthropocene. We used linear mixed‐effects models to quantify the relationship between landscape resistance and genetic distance among individuals, which indicated that both isolation by resistance and geographic distance govern gene flow. Gene flow was highest among subpopulations occupying large tracts of contiguous habitat, was reduced among subpopulations in the Madrean Sky Island Archipelago, where montane habitat exists within a lowland matrix of arid lands, and was essentially nonexistent between two isolated subpopulations. We found significant asymmetric gene flow supporting the hypothesis that bears expanded northward from a Pleistocene refugium located in the American Southwest and northern Mexico and that major highways were not yet affecting gene flow. The potential vulnerability of the species to climate change, transportation infrastructure, and the US–Mexico border wall highlights conservation challenges and opportunities for binational collaboration. [ABSTRACT FROM AUTHOR]

In 1995, eight female pumas from Texas (Puma concolor stanleyana) were introduced into five areas in South Florida to remediate morphological and biomedical correlates of inbreeding depression that threatened the long-term survival of Florida panthers (P. c. coryi). Initial analysis of the results of this genetic introgression initiative has highlighted its success, including growth of the population, increased genetic heterozygosity, and reduced frequencies of physical traits associated with inbreeding, including cryptorchidism. However, panthers remain isolated from other puma populations and natural gene flow is not currently plausible. Using data collected from 65 panthers in the post-genetic introgression era (1998–2020), we assessed the benefits accrued to male panther reproductive parameters via this management initiative, the effect of genetic variables, and compared results to historic data. Microsatellite data were used to determine individual heterozygosity levels and qualify panther genetic ancestry as admixed (i.e., panthers descended from crosses with female Texas puma) or canonical (i.e., panthers that comprised most of the population prior to genetic introgression). A total of 47 admixed and 10 canonical panthers were identified; mean individual heterozygosity of canonical panthers (0.39) was significantly different from admixed panthers (0.63; t54 = 4.7, P-value < 0.001). Admixed panthers exhibited higher mean values for total testicular volume, structurally normal spermatozoa, and total sperm in comparison to canonical panthers. The progressive improvement of sperm metrics demonstrates that the benefits of genetic introgression continue to have a positive impact on the population >25 years since the release of the Texas pumas. However, the Florida panther population remains small, isolated, and vulnerable to deterministic and stochastic events that warrants continued monitoring to assess when additional genetic introgression initiatives will need to be implemented in the future. [ABSTRACT FROM AUTHOR]

In 1995, eight female pumas from Texas (Puma concolor stanleyana) were introduced into five areas in South Florida to remediate morphological and biomedical correlates of inbreeding depression that threatened the long-term survival of Florida panthers (P. c. coryi). Initial analysis of the results of this genetic introgression initiative has highlighted its success, including growth of the population, increased genetic heterozygosity, and reduced frequencies of physical traits associated with inbreeding, including cryptorchidism. However, panthers remain isolated from other puma populations and natural gene flow is not currently plausible. Using data collected from 65 panthers in the post-genetic introgression era (1998–2020), we assessed the benefits accrued to male panther reproductive parameters via this management initiative, the effect of genetic variables, and compared results to historic data. Microsatellite data were used to determine individual heterozygosity levels and qualify panther genetic ancestry as admixed (i.e. panthers descended from crosses with female Texas puma) or canonical (i.e. panthers that comprised most of the population prior to genetic introgression). A total of 47 admixed and 10 canonical panthers were identified; mean individual heterozygosity of canonical panthers (0.39) was significantly different from admixed panthers (0.63; t 54 = 4.7, P -value < 0.001). Admixed panthers exhibited higher mean values for total testicular volume, structurally normal spermatozoa, and total sperm in comparison to canonical panthers. The progressive improvement of sperm metrics demonstrates that the benefits of genetic introgression continue to have a positive impact on the population >25 years since the release of the Texas pumas. However, the Florida panther population remains small, isolated, and vulnerable to deterministic and stochastic events that warrants continued monitoring to assess when additional genetic introgression initiatives will need to be implemented in the future. [ABSTRACT FROM AUTHOR]

Pathogen management strategies in wildlife are typically accompanied by an array of uncertainties such as the efficacy of vaccines or potential unintended consequences of interventions. In the context of such uncertainties, models of disease transmission can provide critical insight for optimizing pathogen management, especially for species of conservation concern. The endangered Florida panther experienced an outbreak of feline leukaemia virus (FeLV) in 2002–2004, and continues to be affected by this deadly virus. Ongoing management efforts aim to mitigate the effects of FeLV on panthers, but with limited information about which strategies may be most effective and efficient.We used a simulation‐based approach to determine optimal FeLV management strategies in panthers. We simulated the use of proactive FeLV management strategies (i.e. proactive vaccination) and several reactive strategies, including reactive vaccination and test‐and‐removal. Vaccination strategies accounted for imperfect vaccine‐induced immunity, specifically partial immunity in which all vaccinates achieve partial pathogen protection. We compared the effectiveness of these different strategies in mitigating the number of FeLV mortalities and the duration of outbreaks.Results showed that inadequate proactive vaccination can paradoxically increase the number of disease‐induced mortalities in FeLV outbreaks. These effects were most likely due to imperfect vaccine immunity causing vaccinates to serve as a semi‐susceptible population, thereby allowing outbreaks to persist in circumstances otherwise conducive to fadeout. Combinations of proactive vaccination with reactive test‐and‐removal or vaccination, however, had a synergistic effect in reducing the impacts of FeLV outbreaks, highlighting the importance of using mixed strategies in pathogen management.Synthesis and applications. Management‐informed disease simulations are an important tool for identifying unexpected negative consequences and synergies among pathogen management strategies. In particular, we find that imperfect vaccine‐induced immunity necessitates further consideration to avoid unintentionally worsening epidemics in some conditions. However, mixing proactive and reactive interventions can improve pathogen control while mitigating uncertainties associated with imperfect interventions. [ABSTRACT FROM AUTHOR]

Wildlife translocations are a commonly used strategy in endangered species recovery programmes. Although translocations require detailed assessment of risk, their impact on parasite distribution has not been thoroughly assessed. This is despite the observation that actions that alter host–parasite distributions can drive evolution or introduce new parasites to previously sequestered populations. Here, we use a contemporary approach to amplify viral sequences from archived biological samples to characterize a previously undocumented impact of the successful genetic rescue of the Florida panther (Puma concolor coryi). Our efforts reveal transmission of feline immunodeficiency virus (FIV) during translocation of pumas from Texas to Florida, resulting in extirpation of a historic Florida panther FIV subtype and expansion of a genetically stable subtype that is highly conserved in Texas and Florida. We used coalescent theory to estimate viral demography across time and show an exponential increase in the effective population size of FIV coincident with expansion of the panther population. Additionally, we show that FIV isolates from Texas are basal to isolates from Florida. Interestingly, FIV genomes recovered from Florida and Texas demonstrate exceptionally low interhost divergence. Low host genomic diversity and lack of additional introgressions may underlie the surprising lack of FIV evolution over 2 decades. We conclude that modern FIV in the Florida panther disseminated following genetic rescue and rapid population expansion, and that infectious disease risks should be carefully considered during conservation efforts involving translocations. Further, viral evolutionary dynamics may be significantly altered by ecological niche, host diversity and connectivity between host populations. [ABSTRACT FROM AUTHOR]

Movement patterns can influence an animal's ability to secure food, find mates, and avoid enemies, potentially affecting individual fitness. We studied movement patterns of 10 male and 3 female endangered Florida panthers (Puma concolor coryi) using location data collected from a long-term (2005-2012) GPS collar study. Males traveled faster and covered longer daily distances than females during both the wet and dry seasons (wet:dry- males 289:372 m/h and 4,616:6,701 m; females 186:280 m/h and 2,629:5,239 m). Panthers occupying higherselected habitat traveled faster, but with shorter daily movement distances in comparison to habitats that were less frequently selected. An index of risk (derived using traffic volume and road density) that was linked to habitat predicted to be avoided by panthers was associated with reduced daily movement distances. Our results suggest that Florida panthers alter their movement patterns in response to environmental change and anthropogenic disturbances. [ABSTRACT FROM AUTHOR]

Reliably estimating the abundance of rare or elusive animals is notoriously difficult. An archetypical example is the endangered Florida panther, whose conservation status is intrinsically linked to population size, but for which reliable abundance information is lacking across its range. This is due not only to the inherent difficulty of sampling a rare and elusive species over a large geographic area, but also because of restricted scientific access to private land., Human interactions with wildlife are a regular occurrence, and interactions with non-scientists constitute an important and underutilized source of information about species distribution and abundance. For example, motor vehicle collisions with Florida panthers are recurrent on the vast network of roads within the public and private lands comprising its range in southern Florida, USA., Capitalizing on a tendency for the public to report collisions with species of concern to wildlife officials, we describe a novel methodology using public reports along with routine telemetry monitoring data to produce the first statistically defensible population estimates for the Florida panther across its entire breeding range. In essence, our approach uses traffic volume and road density to estimate the probability of motor vehicle collision mortality from telemetered animals and models counts reported by the public accordingly., Despite low motor vehicle collision mortality probabilities, our methodology achieved abundance estimates of reasonable precision (29% CV) that was similar to that of previous panther studies using conventional approaches on much smaller study areas. While recovery criteria require establishment of three distinct populations of 240 Florida panthers, we found this single population may never have exceeded 150 individuals from 2000 to 2012., Synthesis and applications. By extracting critical demographic information from underutilized aspects of human-wildlife ecology, our citizen-based approach can cost less than conventional alternatives and could conceivably be used for long-term population monitoring of other species over broad geographic areas, for example from reports of avian wind farm collisions, beached whales or marine mammal boat strikes. An additional benefit is that it can be applied to historical data sets of carcass recovery programmes, in our case permitting abundance estimation over a 13-year period. [ABSTRACT FROM AUTHOR]

Background: Parasites of the genus Trichinella are zoonotic nematodes common in carnivores throughout the world. We determined the prevalence and species of Trichinella infections in Florida panthers (Puma concolor coryi). Methods: Tongues from Florida panthers were collected at necropsy and examined by pepsin-HCl artificial digestion for infection with Trichinella spp. DNA was extracted from larvae and multiplex PCR using Trichinella species-specific primers was used to genotype the worms. Results: Trichinella spp. larvae were detected in 24 of 112 (21.4%; 14.6%-30.3%) panthers. Sixteen of the panthers (14.3%) were infected with T. pseudospiralis, 1 (0.9%) was infected with T. spiralis, and 2 (1.8%) had mixed infections of T. pseudospiralis and T. spiralis. Trichinella spp. larvae from 5 panthers were not identified at the species level due to degraded DNA. Conclusions: This is the highest prevalence of T. pseudospiralis detected in North America up to now and suggests the Florida panther is a key mammalian reservoir of this parasite in southern Florida. Trichinella pseudospiralis can infect both mammals and birds indicating the source of infection for Florida panthers could be broader than believed; however, birds represent a small percentage (0.01%) of the cat's diet. Since wild pigs (Sus scrofa) can be parasitized by both T. pseudospiralis and T. spiralis and these swine can comprise a large portion (~40%) of a panther's diet in Florida, we believe that Florida panthers acquired these zoonotic parasites from feeding on wild pigs. [ABSTRACT FROM AUTHOR]

Genetic data are increasingly used to describe the structure of wildlife populations and to infer landscape influences on functional connectivity. To accomplish this, genetic structure can be described with a multitude of methods that vary in their assumptions, advantages and limitations. While some methods discriminate distinct subpopulations separated by sharp genetic boundaries (i.e. barrier detection or clustering methods), other methods estimate gradient genetic structures using individual-based genetic distances. We present an analytical framework based on individual ancestry values that combines these different approaches and can be used to a) test for local barriers to gene flow and b) evaluate effects of landscape gradients through individual-based genetic distances that account for hierarchical genetic structure. We illustrate the approach with a data set of 371 cougars Puma concolor from a 217 000 km2 study area in Idaho and western Montana (USA) that were genotyped at 12 microsatellite loci. Results suggest that cougars in the region show a complex, hierarchical genetic structure that is influenced by a local barrier to gene flow (an urban population cluster connected by high traffic volumes), different landscape features (the Snake River Plain, forested habitat), and geographic distance. Our novel approach helped to elucidate the relative influence of these factors on different hierarchical levels of population structure, which was not possible when using either clustering methods or standard genetic distances. Results obtained with our analytical framework highlight the need for multi-scale management of cougars in the region and show that landscape heterogeneity can create complex genetic structures, even in generalist species with high dispersal capabilities. [ABSTRACT FROM AUTHOR]

Crossing structures are an effective method for mitigating habitat fragmentation and reducing wildlife-vehicle collisions, although high construction costs limit the number that can be implemented in practice. Therefore, optimizing the placement of crossing structures in road networks is suggested as a strategic conservation planning method. This research explores two approaches for using the maximal covering location problem ( MCLP) to determine optimal sites to install new wildlife crossing structures. The first approach is based on records of traffic mortality, while the second uses animal tracking data for the species of interest. The objective of the first is to cover the maximum number of collision sites, given a specified number of proposed structures to build, while the second covers as many animal tracking locations as possible under a similar scenario. These two approaches were used to locate potential wildlife crossing structures for endangered Florida panthers ( Puma concolor coryi) in Collier, Lee, and Hendry Counties, Florida, a population whose survival is threatened by excessive traffic mortality. Historical traffic mortality records and an extensive radio-tracking dataset were used in the analyses. Although the two approaches largely select different sites for crossing structures, both models highlight key locations in the landscape where these structures can remedy traffic mortality and habitat fragmentation. These applications demonstrate how the MCLP can serve as a useful conservation planning tool when traffic mortality or animal tracking data are available to researchers. [ABSTRACT FROM AUTHOR]

The breeding population of the endangered Florida panther (Puma concolor coryi) is confined to the southern portion of the Florida peninsula. During the 20th century, a combination of isolation and small population size resulted in increased inbreeding. This ultimately led to a genetic restoration program in 1995 to alleviate correlates of inbreeding depression and avert extinction of the Florida panther. Genetic restoration involved the release of 8 female Texas pumas into the wild Florida population, a management initiative that has significantly improved the outlook for recovery. It is unknown whether genetic restoration changed the distinctive cranial morphology of the Florida panther; and whether some metrics that were historically used to differentiate Florida panthers from other subspecies of P. concolor are still valid. We used a high-resolution digital imaging system to compare cranial morphology from several groupings of Florida panthers that were defined by genetic restoration to elucidate any morphological changes this event may have had on cranial profile. Our results indicated that cranial measurements of Florida panthers were not significantly altered by genetic restoration. [ABSTRACT FROM AUTHOR]

Understanding the social dynamics of large carnivores is critical to effective conservation and management planning. Wemade the first attempt to delineate both paternity and relatedness for a population of cougar (Puma concolor) using microsatellite data. We analyzed a long-term genetic dataset collected from a hunted population in the Garnet Mountains of western Montana. We assigned paternity for 62.5% of litters sampled using both exclusion and likelihood analyses. Attempts at reconstructing unsampled paternal genotypes resulted in delineating possible sires for 8 more litters. Sires were on average younger than reported for males involved in pairings assessed via field data in other cougar populations. Although most mating pairs were unrelated, 5 of 17 pairings involved cougars with levels of relatedness corresponding to half-sibling and full-sibling or parent offspring relationship (r = 0.215-0.575). Relatedness among adult and subadult males was higher than relatedness levels among adult and subadult females. Relatedness among males in the Garnet population differed from patterns hypothesized to occur under male-biased dispersal theories for cougars. The long-term impact of the turnover of resident cougars in hunted populations is still unclear and warrants additional research. Our results highlight the utility of monitoring cougar demographic parameters using a combination of genetic and field data that in turn may assist managers with determining cougar harvest quotas or strategies, harvest seasons, sustainable harvest, and the appropriate management level of cougar populations. [ABSTRACT FROM AUTHOR]

Florida panthers (Puma concolor coryi) are listed as an endangered subspecies in the United States and they exist in a single Florida population with <100 individuals; all known reproduction occurs south of Lake Okeechobee. Habitat loss is the biggest threat to this small population and previous studies of habitat selection have relied on very high frequency (VHF) telemetry data collected almost exclusively during diurnal periods. We investigated habitat selection of 12 panthers in the northern portion of the breeding range using 1) Global Positioning System (GPS) telemetry data collected during nocturnal and diurnal periods and 2) VHF telemetry data collected only during diurnal periods. Analysis of both types of telemetry data yielded similar results as panthers selected upland (P < 0.001) anti wetland (P < 0.001) forested habitat types. Our results indicated that forests are the habitats selected by panthers and generally support the current United States Fish and Wildlife Service panther habitat ranking system. We suggest that future studies with greater numbers of panthers should investigate panther habitat selection using GPS telemetry data collected throughout the range of the Florida panther and with location attempts scheduled more evenly across the did period. Global Positioning System radiocollars were effective at obtaining previously unavailable nocturnal telemetry data on panthers; however, we recommend that panther researchers continue to collect VHF telemetry data until acquisition rates and durability of GPS collars improve. [ABSTRACT FROM AUTHOR]

American black bears (Ursus americanus) have recolonized parts of their former range in the Trans-Pecos region of western Texas after a >40-year absence. Assessment of genetic variation, structuring, gene flow, and dispersal among bear populations along the borderlands of Mexico and Texas is important to gain a better understanding of recolonization by large carnivores. We evaluated aspects of genetic diversity and gene flow for 6 sampling areas of black bears in southwestern North America using genotypic data from 7 microsatellite loci. Our results indicated that genetic diversity generally was high in the metapopulation of black bears in northern Mexico and western Texas. The episodic gene flow occurring via desert corridors between populations in northern Mexico and those in western Texas has permitted the establishment of only moderate levels of genetic structuring. Bayesian clustering analyses and assignment testing depicted the presence of 3 subpopulations among our 6 sampling areas and attested to the generally panmictic nature of bear populations in the borderlands region. The potentially ephemeral nature of the small populations in western Texas and genotypic characteristics of bears recolonizing these habitats attest to the importance of linkages along this portion of the borderlands of the United States and Mexico to effectively conserve and manage the species in this part of its range. [ABSTRACT FROM AUTHOR]

Snow leopards ( Panthera uncia) are elusive endangered carnivores found in remote mountain regions of Central Asia. New methods for identifying and counting snow leopards are needed for conservation and management efforts. To develop molecular genetic tools for individual identification of hair and faecal samples, we screened 50 microsatellite loci developed for the domestic cat ( Felis catus) in 19 captive snow leopards. Forty-eight loci were polymorphic with numbers of alleles per locus ranging from two to 11. The probability of observing matching genotypes for unrelated individuals (2.1 × 10−11) and siblings (7.5 × 10−5) using the 10 most polymorphic loci was low, suggesting that this panel would easily discriminate among individuals in the wild. [ABSTRACT FROM AUTHOR]

The identification of carnivores responsible for preying on wild or domestic ungulates often is of interest to wildlife managers. Typically, field personnel collect a variety of data at mortality sites including scat or hair samples that may have been deposited by the predator. We compared mitochondrial DNA (mtDNA) analysis of hair and scat samples (n = 122) collected at elk (Cervus elaphus) mortality sites between 1997 and 2004 in north-central Idaho, USA, with field identification of carnivore presence. We amplified mtDNA from samples via a 2-step process involving an initial screening for American black bears (Ursus americanus), brown bears (Ursus arctos), and gray wolves (Canis lupus) using a length variation in the 5′ hypervariable section of the control region. Samples that failed the first screening subsequently were analyzed using conserved mtDNA primers that amplify a wide array of vertebrates. Species identification success rate was high (88.5%) and established the presence of 3 predators at elk mortality sites including black bears (55.7%), cougars (Puma concolor; 27.9%), and coyotes (Canis latrans; 6.6%). Attempts at hair and scat identification by field personnel were correct for 58% of hair samples and 79% of fecal samples. Results from these analyses demonstrate the merits of combining field mortality assessments with mtDNA species identification to aid wildlife managers in more accurately pin-pointing predators involved in either predation or depredation events. [ABSTRACT FROM AUTHOR]

American black bears (Ursus americanus) have recolonized western Texas following extirpation in the mid-1900s. Knowledge of winter ecology of black bears is important for conservation and management because denning, parturition, and early cub development occur during this period. We monitored 13 radiocollared black bears for 22 den-years in Big Bend National Park (BBNP) during 1998-2003. All pregnant females (n=6), 2 females with yearlings, 7 subadults, and 1 adult male denned. Three females with yearlings remained active during winter 1998-1999. We located 4 cave dens, 5 ground dens, and 6 rock-pile dens. Volume and elevation of den sites averaged 2.00 m3 (SD=1 .51) and 1,800 m (SD=346), respectively. Mean (±SD) dates of den entrance and emergence for 5 pregnant females were 30 December±17 days and 27 April±21 days, respectively, producing a mean denning period of 118±29 days. Pregnant females exited dens later (P= 0.003) and denned longer (P=0.02) than solitary females and males. Black bears in western Texas used den sites located in higher elevations that were remote and highly defensible. A den-habitat model described less than 56 km2 of: suitable denning habitat with- in and bordering BBNP. Resource managers should reduce visitor and management activities in and around potential denning areas during winter. [ABSTRACT FROM AUTHOR]

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Natural recolonization by large carnivores has rarely been documented. American black bears (Ursus americanus) recently (1988-present) recolonized portions of their former range in western Texas. We used mtDNA sequence data (n = 144 bears) from 7 populations of southwestern black bears in New Mexico, Texas, and northern Mexico to test predictions regarding metapopulation structure of the species in this region and the source of recolonization in western Texas. Six variable nucleotides were detected, resulting in 5 mtDNA haplotypes. Although within-site diversity of haplotypes (h) and nucleotides (π) was low, a high degree of genetic partitioning among sites was detected (&PhiST = 0.6301). Analyses pinpointed northern Mexico as the source of black bears for western Texas. Female-mediated gene flow is proceeding slowly in this system (Nfm = 0.4961 individuals/generation), but its occurrence was inferred via field observations. Nested clade analyses indicated that populations of bears in the Mexico-Texas region (area that encompasses mountain ranges within Nuevo Leon and Coahuila, Mexico, northward to smaller ranges located in the Trans-Pecos region of western Texas) were connected via restricted gene flow due to isolation by distance. Long-distance, colonization is the likely cause of extant geographical associations between New Mexican and Mexico-Texas populations. The naturally fragmented, xeric environment of the Chihuahuan Desert impedes colonization, but is not a complete barrier to this process. Conservation initiatives concerning recolonization by black bears within the Mexico-Texas mainland-island metapopulation should focus on preventing human-bear interactions and maintaining corridors for dispersal between the mainland populations in Mexico and the island populations in western Texas. [ABSTRACT FROM AUTHOR]

The upper Cahaba River in Alabama has experienced extensive urban development in its watershed in recent years. To assess the effects that these developments have had on the ichthyofauna, we compared data from samples made at 12 stations by other researchers prior to 1984 todata from samples collected by us at the same sites between 1995-97.Historical collections produced a total of 44 species, whereas recent samples produced 42. Two species, the blue shiner (Cyprinella caerulea) and the Alabama shad (Alosa alabamae), have been extirpated fromthis system. Relative abundances of the various taxa in recent samples correlated poorly with those of historical samples, indicating that the compositions of the ichthyological communities have changed. Disturbancetolerant cyprinids (minnows) have generally increased in percent relative abundance (PRA) in recent collections, whereas the disturbance-sensitive cyprinids have generally decreased. The PRA of percids (darters) has decreased in recent collections, especially the disturbance-sensitive species such as the coal darter (Percina brevicauda) and the greenbreast darter (Etheostoma jordani). The ichthyofaunaldiversity, as measured by several indices, has decreased in recent samples. These changes in the fish populations have occurred concurrently with extensive urbanization and resultant degradation of water and habitat that has taken place in the watershed over the last 20 years. [ABSTRACT FROM AUTHOR]