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ABSTRACT: Translocations are an important tool for wildlife conservation, although progress in the field of reintroduction biology has been hindered by the ad hoc and opportunistic nature of many translocations. We used an experimental translocation to elucidate the role of raccoon roundworm (Baylisascaris procyonis) and inbreeding depression in the decline of the Allegheny woodrat (Neotoma magister), an endangered species. We translocated woodrats from genetically diverse populations in the core of the species range to 4 previously occupied sites (reintroductions) and 2 sites supporting genetically depauperate populations (reinforcements) in Indiana (U.S.A.). In 2 reintroduction sites and 1 reinforcement site, we distributed anthelmintic baits to passively deworm raccoons and reduce the risk of woodrat exposure to roundworms. The remaining sites served as controls. We used raccoon latrine surveys and fecal flotation to monitor temporal variability in roundworm prevalence and effect of treatment. We used live trapping and microsatellite genotyping to monitor the demographic and genetic response of translocated populations over the following 54 months. At the conclusion of the study, 4 of 6 translocations were successfully maintaining abundance through local recruitment. The distribution of anthelmintic baits reduced levels of roundworm contamination, but levels of contamination were also low in 2 of 3 control sites. Reintroductions failed at control sites, one of which was due to high roundworm exposure. The other failed control reintroduction was likely attributable to demographic stochasticity and limited reproductive potential following initial mortality within the first 4 months. In both control and treatment reinforcements, increases in both allelic richness and heterozygosity were accompanied by increases in abundance, which is suggestive of genetic rescue. Our results demonstrate that mitigation of roundworm exposure through the distribution of anthelmintic baits can facilitate woodrat recovery and that diversity within genetically depauperate populations can be restored through the introduction of a limited number of individuals. El Uso de Reubicaciones Experimentales de Neotoma magister para Descifrar Agentes Causales de Disminución.
Conservation Biology 05/2013; · 4.69 Impact Factor
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ABSTRACT: Anthropogenic changes in land use and the extirpation of apex predators have facilitated explosive growth of mesopredator populations. Consequently, many species have been subjected to extensive control throughout portions of their range due to their integral role as generalist predators and reservoirs of zoonotic disease. Yet, few studies have monitored the effects of landscape composition or configuration on the demographic or behavioral response of mesopredators to population manipulation. During 2007 we removed 382 raccoons (Procyon lotor) from 30 forest patches throughout a fragmented agricultural ecosystem to test hypotheses regarding the effects of habitat isolation on population recovery and role of range expansion and dispersal in patch colonization of mesopredators in heterogeneous landscapes. Patches were allowed to recolonize naturally and demographic restructuring of patches was monitored from 2008-2010 using mark-recapture. An additional 25 control patches were monitored as a baseline measure of demography. After 3 years only 40% of experimental patches had returned to pre-removal densities. This stagnant recovery was driven by low colonization rates of females, resulting in little to no within-patch recruitment. Colonizing raccoons were predominantly young males, suggesting that dispersal, rather than range expansion, was the primary mechanism driving population recovery. Contrary to our prediction, neither landscape connectivity nor measured local habitat attributes influenced colonization rates, likely due to the high dispersal capability of raccoons and limited role of range expansion in patch colonization. Although culling is commonly used to control local populations of many mesopredators, we demonstrate that such practices create severe disruptions in population demography that may be counterproductive to disease management in fragmented landscapes due to an influx of dispersing males into depopulated areas. However, given the slow repopulation rates observed in our study, localized depopulation may be effective at reducing negative ecological impacts of mesopredators in fragmented landscapes at limited spatial and temporal scales.
PLoS ONE 01/2013; 8(3):e58982. · 4.09 Impact Factor
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ABSTRACT: Twenty-six polymorphic microsatellite markers were developed for the fox squirrel (Sciurus niger). The number of alleles ranged from 2 to 11 and observed heterozygosities ranged from 0.037 to 0.815. Preliminary screening
revealed that numerous loci also were polymorphic in other squirrel species: Sciurus carolinensis and Tamiasciurus hudsonicus. These loci should be useful tools for investigating the social structure, mating tactics and movement behavior of fox squirrels.
Conservation Genetics 05/2012; 10(5):1545-1548. · 1.61 Impact Factor
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ABSTRACT: Human land-use practices have dramatically altered the composition and configuration of native habitats throughout many ecosystems.
Within heterogeneous landscapes generalist predators often thrive, causing cascading effects on local biological communities,
yet there are few data to suggest how attributes of fragmentation influence local population dynamics of these species. We
monitored 25 raccoon (Procyon lotor) populations from 2004 to 2009 in a fragmented agricultural landscape to evaluate the influence of local and landscape habitat
attributes on spatial and temporal variation in demography. Our results indicate that agricultural ecosystems support increased
densities of raccoons relative to many other rural landscapes, but that spatial and temporal variation in demography exists
that is driven by non-agricultural habitat attributes rather than the availability of crops. At the landscape scale, both
density and population stability were positively associated with the size and contiguity of forest patches, while at the local
scale density was positively correlated with plant diversity and the density of tree cavities. In addition, populations occupying
forest patches with greater levels of plant diversity and stable water resources exhibited less temporal variability than
populations with limited plant species complexity or water availability. The proportion of populations comprised of females
was most strongly influenced by the availability of tree cavities and soft mast. Despite the abundance of mesopredators in
heterogeneous landscapes, our results indicate that all patches do not contribute equally to the regional abundance and persistence
of these species. Thus, a clear understanding of how landscape attributes contribute to variation in demography is critical
to the optimization of management strategies.
KeywordsAge structure–Agricultural ecosystem–Disease–Habitat quality–Population dynamics–Predation–
Procyon lotor
–Program MARK–Raccoon–Sex ratio
Landscape Ecology 04/2012; 26(7):937-950. · 3.06 Impact Factor
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ABSTRACT: We identified vertebrate scavengers of small mammal carcasses at the 780-km2 Savannah River Site during the winter of 2000–2001. Rodent carcasses, differing in size and visual conspicuousness, were
placed in upland pine forests and bottomland hardwood forests during six 2-week periods. Sixty-two of the 96 carcasses (65%)
were removed by vertebrates. With the aid of remote photography, we identified 11 species of scavengers removing carcasses.
RaccoonsProcyon lotor, gray foxesUrocyon cinereoargenteus, and feral pigsSus scrofa scavenged most frequently. The mean elapsed time for carcass removal was 5.6 days. The number of carcasses removed by vertebrates
did not differ significantly with respect to carcass size, visual conspicuousness, or habitat type; however, air temperature
was strongly correlated (positively) with carcass removal. Our study demonstrates that many mammal species are capable of
utilizing small carrion items as a food resource, and suggests that scavenging may account for a higher proportion of the
diet of some facultative scavengers than is now widely assumed.
Key wordscarrion-diet-food habits-remote photography-scavenging
Acta theriologica 04/2012; 47(2):185-192. · 0.89 Impact Factor
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ABSTRACT: In order to analyze population genetic structure at multiple spatial scales, 12 polymorphic microsatellite loci were developed
for the eastern hellbender (Cryptobranchus alleganiensis alleganiensis). The number of alleles per locus ranged from 6 to 12 (mean of 9.25 per locus) and the observed heterozygosity ranged from
0.645 to 0.935 among 31 individuals. Two loci exhibited significant deviations from Hardy–Weinberg equilibrium. No evidence
for linkage disequilibrium was detected between pairs of loci. These markers will be used to examine population genetic structure
across the geographic range of this declining species.
KeywordsHellbender-Genetics-Genetic diversity
Conservation Genetics Resources 04/2012; 2(1):89-91. · 0.49 Impact Factor
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ABSTRACT: Twenty-five polymorphic microsatellite markers were developed for the endangered red-cockaded woodpecker (Picoides borealis). The number of alleles ranged from two to five and observed heterozygosities ranged from 0.036 to 0.750. These loci should
be useful tools for conducting research towards the management and conservation of this species.
Conservation Genetics 04/2012; 10(4):1021-1023. · 1.61 Impact Factor
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ABSTRACT: The selection of an appropriate source population may be crucial to the long-term success of reintroduction programs. Appropriate
source populations often are those that originate from the same genetic lineage as native populations. However, source populations
also should exhibit high levels of genetic diversity to maximize their capacity to adapt to variable environmental conditions.
Finally, it is preferable if source populations are genetically representative of historical lineages with little or no contamination
from non-native or domesticated stocks. Here, we use nuclear (microsatellite) and cytoplasmic (mitochondrial control region)
markers to assess the genetic suitability of a potential source population inhabiting the White River in Indiana: the last
extant lake sturgeon population in the Ohio River drainage. The White River population exhibited slightly lower levels of
genetic diversity than other lake sturgeon populations. However, the population’s two private microsatellite alleles and three
private haplotypes suggest a unique evolutionary trajectory. Population assignment tests revealed only two putative migrants
in the White River, indicating the population has almost completely maintained its genetic integrity. Additionally, pairwise
F
ST estimates indicated significant levels of genetic divergence between the White River and seven additional lake sturgeon populations,
suggesting its genetic distinctiveness. These data indicate that the White River population may be the most suitable source
population for future lake sturgeon reintroductions throughout the Ohio River drainage. Furthermore, the White River population
appears to be a reservoir of unique genetic information and reintroduction may be a necessary strategy to ensure the persistence
of this important genetic lineage.
Conservation Genetics 04/2012; 9(5):1195-1209. · 1.61 Impact Factor
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ABSTRACT: Positive demographic responses have been reported in several species where the immigration or supplementation of genetically distinct individuals into wild populations has resulted in a genetic rescue effect. However, rarely have researchers incorporated what could be considerable risk of outbreeding depression into planning for genetic management programs. We assess the genetic effects of an experiment in genetic management involving replicate populations of California bighorn sheep (Ovis canadensis californiana) in Oregon, USA, which previously experienced poor productivity and numerical declines. In the experiment, two declining populations were supplemented with ewes from a more genetically diverse population of California bighorn sheep in Nevada. We incorporated analysis of genetic samples representing both experimental populations prior to supplementation, samples from the supplemented individuals, and samples collected from both experimental populations approximately one generation after supplementation. We used genetic analyses to assess the integration of supplemented and resident populations by identifying interpopulation hybrids. Further, we incorporated demographic simulations to assess the risk of outbreeding depression as a result of the experimental augmentation. Finally, we used data from microsatellites and mitochondrial sequences to determine if genetic management increased genetic diversity in the experimental populations. Our analyses demonstrated the success of genetic management by documenting interpopulation hybrids, identifying no evidence for outbreeding depression as a result of contact between the genetically distinct supplemented and resident populations, and by identifying increased population-level metrics of genetic diversity in postsupplementation populations compared with presupplementation levels.
Ecology and evolution. 02/2012; 2(2):429-43.
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ABSTRACT: Studies of hybrid zones have revealed an array of evolutionary outcomes, yet the underlying structure is typically characterized as one of three types: a hybrid zone, a hybrid swarm or a hybrid taxon. Our primary objective was to determine which of these three structures best characterizes a zone of hybridization between two divergent lineages of mule deer (Odocoileus hemionus), mule deer and black-tailed deer. These lineages are morphologically, ecologically and genetically distinct, yet hybridize readily along a zone of secondary contact between the east and west slopes of the Cascade Mountains (Washington and Oregon, USA). Using microsatellite and mitochondrial DNA, we found clear evidence for extensive hybridization and introgression between lineages, with varying degrees of admixture across the zone of contact. The pattern of hybridization in this region closely resembles a hybrid swarm; based on data from 10 microsatellite loci, we detected hybrids that extend well beyond the F1 generation, did not detect linkage disequilibrium at the centre of the zone and found that genotypes were associated randomly within the zone of contact. Introgression was characterized as bidirectional and symmetric, which is surprising given that the zone of contact occurs along a sharp ecotone and that lineages are characterized by large differences in body size (a key component of mating success). Regardless of the underlying mechanisms promoting hybrid swarm maintenance, it is clear that the persistence of a hybrid swarm presents unique challenges for management in this region.
Molecular Ecology 11/2011; 20(24):5265-79. · 5.52 Impact Factor
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ABSTRACT: Habitat fragmentation and overtrapping are thought to have resulted in severe population declines for fisher (Martes pennanti) across the northeastern United States, and by the end of the 1930s only 3 remnant populations remained. Subsequent trapping cessation, extensive reintroduction programs, and natural recolonization have helped fishers to reclaim much of their historical range. The degree to which these processes have impacted genetic structure in this species, however, remains unknown. We used 11 microsatellites from tissue samples (n = 432) of fishers to characterize contemporary population structure in light of historical population structure and thus to determine the relative influence of anthropogenic disturbances and natural landscape features in shaping genetic structure of the contemporary population. Our results indicated that 3 well-differentiated contemporary populations are present that correspond well with what would be expected based on their reported history. A course barrier to dispersal appears in the western portion of the study area associated with several lakes including Lake George and Great Sacandaga Lake. Large-scale reintroduction efforts and natural recolonizations have largely had predictable impacts on population structure. An important exception is the substantial impact of the reintroduction of fishers to Vermont.
The Journal of heredity 03/2011; 102(3):251-9. · 2.05 Impact Factor
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ABSTRACT: Baylisascaris procyonis roundworms, a parasite of raccoons, can infect humans, sometimes fatally. Parasite eggs can remain viable in raccoon latrines for years. To develop a management technique for parasite eggs, we tested anthelmintic baiting. The prevalence of eggs decreased at latrines, and larval infections decreased among intermediate hosts, indicating that baiting is effective.
Emerging Infectious Diseases 01/2011; 17(1):90-3. · 6.79 Impact Factor
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ABSTRACT: Raccoon (Procyon lotor) latrine surveys are an efficient and cost-effective method to quantify Baylisascaris procyonis exposure risk for intermediate hosts. Nevertheless, current methodologies may introduce bias by homogenizing scats collected within latrines and estimating exposure risk at the latrine scale. The objective of this study was to examine the potential for raccoon latrine size to bias estimates of risk of exposure when utilizing current methodologies that pool scats prior to analysis. We accomplished this by evaluating correlation of the presence of B. procyonis eggs among scats collected within latrines. Specimens were collected in southern Indiana during November and December of 2006. Raccoon scats collected within latrines exhibited no correlation with the presence of B. procyonis eggs. Accordingly, to eliminate the bias introduced by pooling scats within latrines, scats rather than latrines should be treated as the sampling unit for estimating risk of exposure for intermediate hosts. Further, evaluation of exposure risk based on individual scats has the potential to greatly reduce the time and expense associated with obtaining precise estimates of B. procyonis exposure risk.
Journal of wildlife diseases 07/2010; 46(3):929-33. · 1.08 Impact Factor
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ABSTRACT: Using molecular techniques, we examined patterns of paternity in Virginia opossums occupying a highly fragmented agricultural landscape in northern Indiana. During 2008, we collected tissue from 64 females and their pouch young in 34 forest patches distributed over a 1100-km(2) region. Using genotypes from 10 microsatellite loci, we determined the minimum number of fathers contributing to each litter using GERUD 1.0. Genotyped offspring with known mothers were then analyzed using CERVUS 3.0, incorporating genotypes from 317 males sampled from 2007-2008 to identify potential fathers. Our analyses revealed that promiscuity was common among females, with 26 (41%) litters having > or = 2 sires. Despite the fact that we intensively sampled forest patches for potential fathers, we only were able to identify 13 fathers contributing to 14 litters, with an average Euclidean distance of 18.7 km between father-offspring pairs found in disparate patches (N = 6). Our inability to identify most (85%) fathers of sampled litters, coupled with the extensive distances observed between putative father-offspring pairs, suggests that opossums may not maintain explicit home ranges in highly fragmented landscapes.
The Journal of heredity 12/2009; 101(3):368-73. · 2.05 Impact Factor
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ABSTRACT: The raccoon (Procyon lotor (L., 1758)), a generalist mesocarnivore, has thrived in anthropogenically fragmented landscapes. In this study we utilized 13 microsatellites to analyze the population genetic structure in raccoons occupying an agriculturally fragmented habitat. Our analyses revealed low, but significant, levels of genetic structure (FST = 0.022, P < 0.001) among 645 raccoons inhabiting 29 spatially distinct habitat patches (neighborhoods). We found no evidence for the presence of either isolation by distance or barriers. However, spatial autocorrelation revealed evidence for social structure at the raccoon-neighborhood scale. About 30% of the variance in levels of social structure among raccoon neighborhoods was explained by effects of habitat-patch size and the percentage of land cover represented by forest around the individual habitat patch. We found strong evidence of sex-biased dispersal using direct (parentage analysis) and indirect (relatedness and assignment indices) genetic estimators. However, our analysis revealed that among dispersing raccoons there was no difference in dispersal distance between sexes and that dispersal events are randomly distributed with respect to distance. Our study provides evidence that demographic and behavioral processes affecting raccoon spatial organization may be most critical at very fine scales of biological organization, such as within individual habitat patches.Le raton laveur (Procyon lotor (L., 1758)), un mésocarnivore généraliste, a prospéré dans les paysages fragmentés par l'activité humaine. Nous utilisons, dans notre étude, 13 microsatellites pour déterminer la structure génétique de la population chez des ratons laveurs qui vivent dans un habitat fragmenté par l'agriculture. Nos analyses révèlent des niveaux bas, mais significatifs, de structure génétique (FST = 0,022, P < 0,001) parmi 645 ratons laveurs vivant dans 29 taches d'habitat distinctes (quartiers). Il n'y a aucune indication d'isolement par la distance, ni de barrières. Cependant, l'autocorrélation spatiale donne des indications d'une structure sociale à l'échelle des quartiers de ratons laveurs. Environ 30 % de la variance des niveaux de structure sociale entre les quartiers de ratons laveurs s'explique par les effets de la taille de la tache d'habitat et le pourcentage de la couverture du sol autour des taches individuelles d'habitat qui est représenté par de la forêt. Des estimateurs génétiques directs (analyse de filiation) et indirects (indices de consanguinité et d'attribution) indiquent clairement une dispersion variable en fonction du sexe. Cependant, notre analyse révèle que, parmi les ratons laveurs qui se dispersent, il n'y a pas de différence de distance de dispersion en fonction des sexes et que les événements de dispersion sont répartis au hasard en fonction de la distance. Notre étude fournit des indications que les processus démographiques et comportementaux qui affectent l'organisation spatiale des ratons laveurs peuvent agir de la façon la plus critique aux échelles très fines de l'organisation biologique, par exemple à l'intérieur des taches individuelles d'habitat.
Canadian Journal of Zoology 08/2009; 87(9):814-824. · 1.21 Impact Factor
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ABSTRACT: Twenty-four polymorphic microsatellite markers were developed for the double-crested cormorant (Phalacrocorax auritus). The number of alleles ranged from two to 13 and observed heterozygosities ranged from 0.032 to 0.871. The use of these loci should enable researchers and biologists to learn more about the population structure and ecology of this species.
Molecular Ecology Resources 07/2009; 9(4):1183-5. · 3.06 Impact Factor
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ABSTRACT: Twenty-one polymorphic microsatellite markers were developed for the Virginia opossum (Didelphis virginiana). The number of alleles ranged from two to 13 and observed heterozygosities ranged from 0.464 to 0.964. Significant heterozygote deficiencies were observed at three loci and null alleles were detected at five loci. Evidence for gametic disequilibrium was observed between three sets of paired loci after a sequential Bonferroni correction was applied. These markers will enable us to investigate the mating tactics, movement behaviour and social structure of Virginia opossum populations inhabiting fragmented agricultural landscapes.
Molecular Ecology Resources 07/2009; 9(4):1200-2. · 3.06 Impact Factor
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ABSTRACT: The objective of this study was to characterize the antibody prevalence of important livestock and domestic animal pathogens in raccoons (Procyon lotor) trapped and sampled in 39 forest patches in north-central Indiana, USA, between 2004 and 2005. A total of 459 serum samples were tested for antibodies to Leptospira serovars, 512 for Canine distemper virus (CDV) antibodies, and 340 for antibodies to Porcine reproductive and respiratory syndrome virus (PRRSV). In total, 47, 16, and 0% of the samples were seropositive for at least one Leptospira serovar, CDV, and PRRSV, respectively. Most of the positive Leptospira results were to serovars grippotyphosa (36%), autumnalis (22%), and hardjo (22%). No statistically significant correlation was found between antibody prevalence estimates for different Leptospira serovars. A significant association was found between body weight and antibodies for Leptospira serovars and CDV. In addition, age (adult vs. juvenile) was significantly associated with the presence of CDV antibody, with adults exhibiting a higher prevalence than juveniles. This study confirmed that raccoons in Indiana, USA, are exposed to different Leptospira interrogans serovars and CDV and that age and weight are associated with the presence of antibodies for both pathogens.
Journal of wildlife diseases 05/2009; 45(2):531-6. · 1.08 Impact Factor
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ABSTRACT: Quaternary climatic oscillations greatly influenced the present-day population genetic structure of animals and plants. For species with high dispersal and reproductive potential, phylogeographic patterns resulting from historical processes can be cryptic, overshadowed by contemporary processes. Here we report a study of the phylogeography of Odocoileus hemionus, a large, vagile ungulate common throughout western North America. We examined sequence variation of mitochondrial DNA (control region and cytochrome b) within and among 70 natural populations across the entire range of the species. Among the 1766 individual animals surveyed, we recovered 496 haplotypes. Although fine-scale phylogenetic structure was weakly resolved using phylogenetic methods, network analysis clearly revealed the presence of 12 distinct haplogroups. The spatial distribution of haplogroups showed a strong genetic discontinuity between the two morphological types of O. hemionus, mule deer and black-tailed deer, east and west of the Cascade Mountains in the Pacific Northwest. Within the mule deer lineage, we identified several haplogroups that expanded before or during the Last Glacial Maximum, suggesting that mule deer persisted in multiple refugia south of the ice sheets. Patterns of genetic diversity within the black-tailed deer lineage suggest a single refugium along the Pacific Northwest coast, and refute the hypothesis that black-tailed deer persisted in one or more northern refugia. Our data suggest that black-tailed deer recolonized areas in accordance with the pattern of glacial retreat, with initial recolonization northward along a coastal route and secondary recolonization inland.
Molecular Ecology 04/2009; 18(8):1730-45. · 5.52 Impact Factor
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ABSTRACT: Fourteen polymorphic microsatellite loci were developed for the raccoon tick (Ixodes texanus). Three multiplexed panels comprising the loci were developed and 50 ticks collected from two infected raccoons (Procyon lotor) were genotyped. The number of alleles per locus ranged from five to 22, and single locus heterozygosities ranged from 0.46 to 0.94. Future research will further our understanding of I. texanus biology and help in elucidating the effects of life-history variation on parasite population genetic structure, using I. texanus as a model organism.
Molecular Ecology Resources 01/2009; 9(1):296-8. · 3.06 Impact Factor
