Rodovias podem fragmentar populações por dois mecanismos, mortalidade e evitamento. Como espécies que evitam rodovias são raramente atropeladas por veículos e, então, não são detectadas em monitoramentos de fauna atropelada, outras abordagens são necessárias para identificar se eles estão sendo afetados. Ctenomys minutus (tuco-tuco) é um roedor subterrâneo que habita campos arenosos nas margens de rodovias e são raramente registrados em monitoramentos de fauna atropelada. Buscamos identificar se as rodovias são uma barreira para o fluxo gênico de tuco-tuco baseado em nove loci de microssatélite. Coletamos amostras de tecido epitelial de indivíduos de quatro populações: duas com a presença (Weber e Amaral) e, como controle, duas com a ausência de rodovia (Maribo I e Maribo II). Mensuramos diversidade genética, diferenciação genética (estatística F) e acessamos estrutura genética (agrupamento bayesiano). Não observamos redução na variabilidade genética e encontramos um baixo nível de isolamento entre Weber e Amaral e um isolamento ainda menor entre Maribo I e Maribo II. O método bayesiano separou os indivíduos em dois grupos, onde Maribo I e Maribo II são um grupo consistente e Weber e Amaral possuem fracas diferenciações. Os resultados nos indicam que um efeito de barreira entre as populações separadas pela rodovia está em processo e que é necessário mais tempo para observarmos de forma mais clara o isolamento. São necessários mais estudos genéticos e comportamentais para certificar este padrão. Sob aspectos práticos, seria adequado monitorar as populações afetadas e, eventualmente, aplicar alguma medida de mitigação na estrada pra proporcionar conectividade. Por fim, a abordagem genética se mostrou muito interessante para avaliar este impacto. / Roads can fragment populations by two mechanisms, mortality and avoidance behavior. Since species that avoid roads are rarely killed by vehicles and thus cannot be detected in roadkill surveys, other approaches are necessary to identify whether they are affected. Ctenomys minutus (tuco-tuco) is a subterranean rodent who inhabits sand fields including at the margins of roads, however is rarely recorded on roadkill surveys. We aimed to identify if roads are a barrier to the gene flow of tuco-tuco based on nine microsatellite loci. We collected tissue samples from individuals of four populations: a pair with the presence (Weber and Amaral) and, as control, a pair with absence of a road (Maribo I and Maribo II). We measured the genetic diversity, the genetic differentiation (F-statistics), and assessed the genetic structure (Bayesian clustering). We observed no reduction in genetic variability and a low isolation level in pairwise comparison of Weber and Amaral, which was even lower between Maribo I and Maribo II. The Bayesian method separated individuals into 2 clusters, where Maribo I and Maribo II are one consistent cluster and Weber and Amaral present weak differentiations. The results indicate that a barrier effect between populations separated by roads is in process. More genetic and behavioral studies are needed to confirm this pattern. Under practical aspects, it would be appropriate to monitor the affected populations and possibly apply some mitigation measure on the road to provide connectivity. Finally, genetic approach proved very interesting to evaluate this impact.

Rodovias podem fragmentar populações por dois mecanismos, mortalidade e evitamento. Como espécies que evitam rodovias são raramente atropeladas por veículos e, então, não são detectadas em monitoramentos de fauna atropelada, outras abordagens são necessárias para identificar se eles estão sendo afetados. Ctenomys minutus (tuco-tuco) é um roedor subterrâneo que habita campos arenosos nas margens de rodovias e são raramente registrados em monitoramentos de fauna atropelada. Buscamos identificar se as rodovias são uma barreira para o fluxo gênico de tuco-tuco baseado em nove loci de microssatélite. Coletamos amostras de tecido epitelial de indivíduos de quatro populações: duas com a presença (Weber e Amaral) e, como controle, duas com a ausência de rodovia (Maribo I e Maribo II). Mensuramos diversidade genética, diferenciação genética (estatística F) e acessamos estrutura genética (agrupamento bayesiano). Não observamos redução na variabilidade genética e encontramos um baixo nível de isolamento entre Weber e Amaral e um isolamento ainda menor entre Maribo I e Maribo II. O método bayesiano separou os indivíduos em dois grupos, onde Maribo I e Maribo II são um grupo consistente e Weber e Amaral possuem fracas diferenciações. Os resultados nos indicam que um efeito de barreira entre as populações separadas pela rodovia está em processo e que é necessário mais tempo para observarmos de forma mais clara o isolamento. São necessários mais estudos genéticos e comportamentais para certificar este padrão. Sob aspectos práticos, seria adequado monitorar as populações afetadas e, eventualmente, aplicar alguma medida de mitigação na estrada pra proporcionar conectividade. Por fim, a abordagem genética se mostrou muito interessante para avaliar este impacto. / Roads can fragment populations by two mechanisms, mortality and avoidance behavior. Since species that avoid roads are rarely killed by vehicles and thus cannot be detected in roadkill surveys, other approaches are necessary to identify whether they are affected. Ctenomys minutus (tuco-tuco) is a subterranean rodent who inhabits sand fields including at the margins of roads, however is rarely recorded on roadkill surveys. We aimed to identify if roads are a barrier to the gene flow of tuco-tuco based on nine microsatellite loci. We collected tissue samples from individuals of four populations: a pair with the presence (Weber and Amaral) and, as control, a pair with absence of a road (Maribo I and Maribo II). We measured the genetic diversity, the genetic differentiation (F-statistics), and assessed the genetic structure (Bayesian clustering). We observed no reduction in genetic variability and a low isolation level in pairwise comparison of Weber and Amaral, which was even lower between Maribo I and Maribo II. The Bayesian method separated individuals into 2 clusters, where Maribo I and Maribo II are one consistent cluster and Weber and Amaral present weak differentiations. The results indicate that a barrier effect between populations separated by roads is in process. More genetic and behavioral studies are needed to confirm this pattern. Under practical aspects, it would be appropriate to monitor the affected populations and possibly apply some mitigation measure on the road to provide connectivity. Finally, genetic approach proved very interesting to evaluate this impact.

Rodovias podem fragmentar populações por dois mecanismos, mortalidade e evitamento. Como espécies que evitam rodovias são raramente atropeladas por veículos e, então, não são detectadas em monitoramentos de fauna atropelada, outras abordagens são necessárias para identificar se eles estão sendo afetados. Ctenomys minutus (tuco-tuco) é um roedor subterrâneo que habita campos arenosos nas margens de rodovias e são raramente registrados em monitoramentos de fauna atropelada. Buscamos identificar se as rodovias são uma barreira para o fluxo gênico de tuco-tuco baseado em nove loci de microssatélite. Coletamos amostras de tecido epitelial de indivíduos de quatro populações: duas com a presença (Weber e Amaral) e, como controle, duas com a ausência de rodovia (Maribo I e Maribo II). Mensuramos diversidade genética, diferenciação genética (estatística F) e acessamos estrutura genética (agrupamento bayesiano). Não observamos redução na variabilidade genética e encontramos um baixo nível de isolamento entre Weber e Amaral e um isolamento ainda menor entre Maribo I e Maribo II. O método bayesiano separou os indivíduos em dois grupos, onde Maribo I e Maribo II são um grupo consistente e Weber e Amaral possuem fracas diferenciações. Os resultados nos indicam que um efeito de barreira entre as populações separadas pela rodovia está em processo e que é necessário mais tempo para observarmos de forma mais clara o isolamento. São necessários mais estudos genéticos e comportamentais para certificar este padrão. Sob aspectos práticos, seria adequado monitorar as populações afetadas e, eventualmente, aplicar alguma medida de mitigação na estrada pra proporcionar conectividade. Por fim, a abordagem genética se mostrou muito interessante para avaliar este impacto. / Roads can fragment populations by two mechanisms, mortality and avoidance behavior. Since species that avoid roads are rarely killed by vehicles and thus cannot be detected in roadkill surveys, other approaches are necessary to identify whether they are affected. Ctenomys minutus (tuco-tuco) is a subterranean rodent who inhabits sand fields including at the margins of roads, however is rarely recorded on roadkill surveys. We aimed to identify if roads are a barrier to the gene flow of tuco-tuco based on nine microsatellite loci. We collected tissue samples from individuals of four populations: a pair with the presence (Weber and Amaral) and, as control, a pair with absence of a road (Maribo I and Maribo II). We measured the genetic diversity, the genetic differentiation (F-statistics), and assessed the genetic structure (Bayesian clustering). We observed no reduction in genetic variability and a low isolation level in pairwise comparison of Weber and Amaral, which was even lower between Maribo I and Maribo II. The Bayesian method separated individuals into 2 clusters, where Maribo I and Maribo II are one consistent cluster and Weber and Amaral present weak differentiations. The results indicate that a barrier effect between populations separated by roads is in process. More genetic and behavioral studies are needed to confirm this pattern. Under practical aspects, it would be appropriate to monitor the affected populations and possibly apply some mitigation measure on the road to provide connectivity. Finally, genetic approach proved very interesting to evaluate this impact.

Dens are a critical component of black bear (Ursus americanus) habitat, yet scale-dependent den-site selection has received limited attention. Natural and anthropogenic factors (e.g., vegetation, roads) may also influence bear den-site selection. I quantified black bear denning chronology and den use and evaluated multi-scale den-site selection in Mississippi, USA during 2005–2011. Females entered dens earlier than males and emerged later; multiple den use by both sexes in a single winter was common. I recorded equal numbers of tree and ground dens, with ground dens at higher elevations surrounded by dense vegetation. Chronology and other denning characteristics of bears in Mississippi were similar to other black bear populations in the southeastern United States. Bears exhibited scale-dependent den-site selection selecting sites with greater percentage horizontal cover and farther from roads. Greater percentage horizontal cover may provide security and increase energetic efficiency. Denning farther from roads likely decreases risk of human disturbance.

Roads can negatively impact the survival of wildlife populations through additional mortality from road kill and population fragmentation caused by road avoidance behaviors. The 11.9 mile section of State Route 101 between the towns of San Luis Obispo and Atascadero, CA, USA, cross a mountain lion movement corridor and an area important to maintaining ecological connectivity between protected lands in the Los Padres National Forest to the north and south. I examined the spatial patterns and landscape and roadway factors associated with road kill occurrence for six taxa; large mammals, mesocarnivores, squirrels, rabbits, birds and raptors. Between 1 May 2009 and 30 June 2010 road kills were documented using vehicle-based surveys. Small mammals were the most common road kill (58.3%), followed by mesocarnivores (10.9%), birds (10.6%), rabbits (5.1%), large mammals (3.3%) and raptors (3.2%). Twenty-nine large mammal road kills were observed during the survey period; eighteen mule deer, six black bears and five feral pigs. Road kill was highest in the middle of the survey area between the top of Cuesta Grade and the southern edge of Atascadero and lowest along the Cuesta Grade. I modeled road kill occurrence using logistic regression to determine which landscape and roadway characteristics were associated with road kill locations. Large mammal and mesocarnivore road kills were more likely to occur near riparian corridors. Mesocarnivore and squirrel road kills were associated with locations with greater roadside tree cover. Squirrel and rabbit road kills were more likely to occur along sections of the road with large grassy center medians. I documented animal activity patterns around the roadway during three survey periods (summer 2009, fall 2009 and spring 2010) using remote cameras placed on game trails and underpasses along the roadway. Mule deer displayed crepuscular activity patterns with peaks in activity in the morning between 05:00h and 07:00h and in the evening between 16:00h and 18:00h. Mesocarnivores generally displayed a nocturnal activity patterns with the majority of activity occurring between 18:00h and 06:00h. I used logistic regression to determine if there was a relationship between animal activity patterns and traffic patterns while controlling for time of day, day of the week, and season. Mule deer and mesocarnivore activity patterns varied significantly by time of day and mule deer activity also varied significantly by season; however only mesocarnivore activity varied significantly in relation to traffic volume suggesting that mesocarnivores are less activity when traffic volume is high. Using traffic volume and animal activity patterns I calculated a collision potential value for both mule deer and mesocarnivores. Collision potential for mule deer was high in the morning, between 06:00h and 08:00h, and in the evening, between 16:00h and 18:00h in all three seasons. Collision potential for mesocarnivores was high in the evening in fall 2009 (18:00h and 21:00) and spring 2010 (17:00h), and high in the morning in summer 2009 (09:00h).

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