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Carnivore guilds play a vital role in ecological communities by cascading trophic effects, energy and nutrient transfer, and stabilizing or destabilizing food webs. Consequently, the structure of carnivore guilds can be critical to ecosystem patterns. Body size is a crucial influence on intraguild interactions, because it affects access to prey resources, effectiveness in scramble competition, and vulnerability to intraguild predation. Coyotes (Canis latrans), bobcats (Lynx rufus), gray foxes (Urocyon cinereoargenteus), raccoons (Procyon lotor), red foxes (Vulpes vulpes), and striped skunks (Mephitis mephitis) occur sympatrically throughout much of North America and overlap in resource use, indicating potential for interspecific interactions. Although much is known about the autecology of the individual species separately, little is known about factors that facilitate coexistence and how interactions within this guild influence distribution, habitat use, and temporal activity of the smaller carnivores. To assess how habitat autecology and interspecific interactions affect the structure of this widespread carnivore guild, we conducted a large-scale, non-invasive carnivore survey using an occupancy modeling framework. We deployed remote cameras during 3-week surveys to detect carnivores at 1,118 camera locations in 357 2.6-km2 sections (3–4 cameras/section composing a cluster) in the 16 southernmost counties of Illinois (16,058 km2) during January–April, 2008–2010. We characterized microhabitat at each camera location and landscape-level habitat features for each camera cluster. In a multistage approach, we used information-theoretic methods to evaluate competing models for detection, species-specific habitat occupancy, multispecies co-occupancy, and multiseason (colonization and extinction) occupancy dynamics. We developed occupancy models for each species to represent hypothesized effects of anthropogenic features, prey availability, landscape complexity, and vegetative land cover. We quantified temporal activity patterns of each carnivore species based on their frequency of appearance in photographs. Further, we assessed whether smaller carnivores shifted their diel activity patterns in response to the presence of potential competitors. Of the 102,711 photographs of endothermic animals, we recorded photographs of bobcats (n = 412 photographs), coyotes (n = 1,397), gray foxes (n = 546), raccoons (n = 40,029), red foxes (n = 149), and striped skunks (n = 2,467). Bobcats were active primarily during crepuscular periods, and their activity was reduced with precipitation and higher temperatures. The probability of detecting bobcats decreased after a bobcat photograph was recorded, suggesting avoidance of remote cameras after the first encounter. Across southern Illinois, bobcat occupancy at the camera-location and camera-cluster scale (ψ̂local = 0.24 ± 0.04, camera cluster ψ̂cluster = 0.75 ± 0.06) was negatively influenced by anthropogenic features and infrastructure. Bobcats had high rates of colonization (γ̂ = 0.86) and low rates of extinction (ε̂ = 0.07), suggesting an expanding population, but agricultural land was less likely to be colonized. Nearly all camera clusters were occupied by coyotes (ψ̂cluster = 0.95 ± 0.03). At the local scale, coyote occupancy (ψ̂local = 0.58 ± 0.03) was higher in hardwood forest stands with open understories than in other areas. Compared to coyotes, gray foxes occupied a smaller portion of the study area (ψ̂local = 0.13 ± 0.01, ψ̂cluster = 0.29 ± 0.03) at all scales. At the scale of the camera cluster, gray fox occupancy was highest in fragmented areas with high proportions of forest, and positively related to anthropogenic features within 100% home-range buffers. Red foxes occupied a similar proportion of the study area as gray foxes (ψ̂local = 0.12 ± 0.02, ψ̂cluster = 0.26 ± 0.04) but were more closely associated with anthropogenic features. Only anthropogenic feature models made up the 90% confidence set at all scales of analysis for red foxes. Extinction probabilities at the scale of the camera cluster were higher for both gray foxes (ε̂ = 0.57) and red foxes (ε̂ = 0.35) than their colonization rates (gray fox γ̂ = 0.16, red fox γ̂ = 0.06), suggesting both species may be declining in southern Illinois. Striped skunks occupied a large portion of the study area (ψ̂local = 0.47 ± 0.01, ψ̂cluster = 0.79 ± 0.03) and were associated primarily with anthropogenic features. Raccoons were essentially ubiquitous within the study area, being photographed in 99% of camera clusters. We observed little evidence for spatial partitioning based on interspecific interactions, with the exception of the gray fox-coyote pairs, and found that habitat preferences were more important in structuring the carnivore community. Habitat had a stronger influence on the occupancy of foxes than did the presence of bobcats. However, the level of red fox activity was negatively correlated with bobcat activity. Gray fox occupancy and the number of detections within occupied sites were reduced in camera clusters occupied by coyotes but not bobcat occupancy. Overall, gray fox occupancy was highest at camera locations with fewer hardwood and more conifer trees. However, gray foxes were more likely to occupy camera locations in hardwood stands than conifer stands if coyotes were also present indicating that hardwood stands may enhance gray fox-coyote coexistence. The 2 fox species appeared to co-occur with each other at the local scale more frequently than expected based on their individual selection of habitat. Similarly, occupancy of camera location by red foxes was higher when coyotes were present. These positive spatial associations among canids may be a response to locally high prey abundance or unmeasured habitat variables. Activity levels of raccoons, bobcats, and coyotes were all positively correlated. Overall, our co-occurrence and activity models indicate competitor-driven adjustments in space use among members of a carnivore community might be the exception rather than the norm. Nevertheless, although our results indicate that gray foxes and red foxes currently coexist with bobcats and coyotes, their distribution appears to be contracting on our study area. Coexistence of foxes with larger carnivores may be enhanced by temporal partitioning of activity and by habitat features that reduce vulnerability of intraguild predation. For instance, hardwood stands may contain trees with structure that enhances tree-climbing by gray foxes, a behavior that probably facilitates coexistence with coyotes. Efforts to enhance gray fox populations would likely benefit from increasing the amount of mature oakhickory forest. Additionally, the varying results from different scales of analyses underscore the importance of considering multiple spatial scales in carnivore community studies. Los gremios de carnívoros desempeñan un papel vital en las comunidades ecológicas causando efectos tróficos en cascada, afectando la transferencia de energía y nutrientes, y estabilizando o desestabilizando las redes alimentarias. En consecuencia, la estructura de los gremios de carnívoros puede ser crítica para los patrones de los ecosistemas. El tamaño corporal tiene una influencia crucial en las interacciones intragremio, ya que afecta el acceso a los recursos de presa, la eficacia en la competencia por explotación, y la vulnerabilidad a depredación intragremio. Los coyotes (Canis latrans), linces (Lynx rufus), zorros grises (Urocyon cinereoargenteus), mapaches (Procyon lotor), el zorro (Vulpes vulpes), y zorrillos rayados (Mephitis mephitis) occurren en simpatría en gran parte de América del Norte y se solapan en los recursos que utilizan, lo que indica un potencial para interacciones interespecíficas. Aunque se sabe mucho sobre la autoecología de las especies individuales por separado, poco se sabe acerca de los factores que facilitan la coexistencia y cómo las interacciones dentro de este gremio influencian la distribución, uso de hábitat, y actividad temporal de los carnívoros más pequeños. Para evaluar cómo la autecología del hábitat y las interacciones interespecíficas afectan la estructura de este gremio carnívoro de amplia distribución, realizamos un muestreo de carnívoros no invasivo a gran escala, utilizando un marco de modelos de ocupación. Instalamos cámaras remotas en muestreos de 3 semanas para detectar carnívoros en 1118 locaciones-cámara en 357 secciones de 2.6 km2 (3–4 cámaras / sección conformaron una agrupación) en los 16 condados de más al sur de Illinois (16058 km2) entre enero y abril de 2008–2010. Caracterizamos el microhábitat en cada locación-cámara y las características del hábitat a nivel de paisaje para cada agrupación de cámaras. Con un enfoque de etapas múltiples, utilizamos métodos de teoría de información para evaluar modelos competitivos de detección, ocupación del hábitat de especies específicas, co-ocupación multi-especies, y dinámicas de ocupación multi-especies y multi-estación (colonización y extinción). Desarrollamos modelos de ocupación para cada especie para representar efectos hipotéticos de características antropogénicas, disponibilidad de presas, complejidad del paisaje, y cobertura vegetal. Cuantificamos los patrones de actividad temporal de cada especie carnívora en función de su frecuencia de aparición en fotografías. Además, evaluamos si los carnívoros más pequeños cambian sus patrones de actividad diaria en respuesta a la presencia de competidores potenciales. De las 102711 fotografías de animales endotérmicos, registramos fotografías de linces (n = 412 fotografías), coyotes (n = 1397), zorros grises (n = 546), mapaches (n = 40029), zorros rojos (n = 149), y zorrillos rayados (n = 2467). Los linces estuvieron activos principalmente durante períodos crepusculares, y su actividad se redujo con la precipitación y altas temperaturas. La probabilidad de detectar linces disminuyó después de reg

1. Occupancy estimation and modelling based on detection-nondetection data provide an effective way of exploring change in a species' distribution across time and space in cases where the species is not always detected with certainty. Today, many monitoring programmes target multiple species, or life stages within a species, requiring the use of multiple detection methods. When multiple methods or devices are used at the same sample sites, animals can be detected by more than one method. 2. We develop occupancy models for multiple detection methods that permit simultaneous use of data from all methods for inference about method-specific detection probabilities. Moreover, the approach permits estimation of occupancy at two spatial scales: the larger scale corresponds to species' use of a sample unit, whereas the smaller scale corresponds to presence of the species at the local sample station or site. 3. We apply the models to data collected on two different vertebrate species: striped skunks Mephitis mephitis and red salamanders Pseudotriton ruber. For striped skunks, large-scale occupancy estimates were consistent between two sampling seasons. Small-scale occupancy probabilities were slightly lower in the late winter/spring when skunks tend to conserve energy, and movements are limited to males in search of females for breeding. There was strong evidence of method-specific detection probabilities for skunks. As anticipated, large- and small-scale occupancy areas completely overlapped for red salamanders. The analyses provided weak evidence of method-specific detection probabilities for this species. 4. Synthesis and applications. Increasingly, many studies are utilizing multiple detection methods at sampling locations. The modelling approach presented here makes efficient use of detections from multiple methods to estimate occupancy probabilities at two spatial scales and to compare detection probabilities associated with different detection methods. The models can be viewed as another variation of Pollock's robust design and may be applicable to a wide variety of scenarios where species occur in an area but are not always near the sampled locations. The estimation approach is likely to be especially useful in multispecies conservation programmes by providing efficient estimates using multiple detection devices and by providing device-specific detection probability estimates for use in survey design.

Mesocarnivores fill a vital role in ecosystems through effects on community health and structure. Anthropogenic-altered landscapes can benefit some species and adversely affect others. For some carnivores, prey availability increases with urbanization, but landscape use can be complicated by interactions among carnivores as well as differing human tolerance of some species. We used camera traps to survey along a gradient of urban, rural, and forest cover to quantify how carnivore landscape use varies among guild members and determine if a species was a human exploiter, adapter, or avoider. Our study was conducted in and around Corvallis, Oregon from April 2018 to February 2019 (11,914 trap nights) using 47 camera trap locations on a gradient from urban to rural. Our focal species were bobcat ( Lynx rufus ), coyote ( Canis latrans ), gray fox ( Urocyon cinereoargenteus ), opossum ( Didelphis virginiana ), raccoon ( Procyon lotor ), and striped skunk ( Mephitis mephitis ). Raccoon and opossum were human exploiters with low use of forest cover and positive association with urban and rural developed areas likely due to human-derived resources as well as some refugia from larger predators. Coyote and gray fox were human adapters with high use of natural habitats while the effects of urbanization ranged from weak to indiscernible. Bobcat and striped skunk appeared to be human avoiders with negative relationship with urban cover and higher landscape use of forest cover. We conducted a diel temporal activity analysis and found mostly nocturnal activity within the guild, but more diurnal activity by larger-bodied predators compared to the smaller species. Although these species coexist as a community in human-dominated landscapes throughout much of North America, the effects of urbanization were not equal across species. Our results, especially for gray fox and striped skunk, are counter to research in other regions, suggesting that mesopredator use of urbanized landscapes can vary depending on the environmental conditions of the study area and management actions are likely to be most effective when decisions are based on locally derived data.

Babesia species are intraerythrocytic protozoan parasites that infect a variety of hosts. The goal of this study was to evaluate the piroplasm species present in skunks in various states in the United States and determine whether there was any geographic variation. Spleen, whole blood, or blood on filter paper were received from Pennsylvania, Kentucky, North Carolina, South Carolina, Georgia, Missouri, Louisiana, Texas, Kansas, and California, and were tested for Babesia sp. We tested four species of skunks including striped skunk ( Mephitis mephitis, n  = 72), eastern spotted skunk ( Spilogale putorius, n  = 28), western spotted skunk ( Spilogale gracilis, n  = 15), and hog-nosed skunk ( Conepatus leuconotus, n  = 11). A PCR assay targeting the 18S rRNA region and cox1 region were used to determine if skunks were infected with piroplasms and for phylogenetic analyses. A total of 48.4% (61/126) of skunks tested positive for a Babesia species. Both the 18S and cox1 analysis supported a skunk-specific Babesia microti -like sp. of carnivores as well as a species in the B. microti complex that is phylogenetically unique from both B. microti of humans and the B. microti- like sp. of carnivores. In the 18S analysis, there was a third species of Babesia in hog-nosed skunks in the western piroplasm group. This study shows that at least three species of piroplasms occur in skunk species in the United States and further highlights the importance of phylogenetic analyses and the use of multiple gene targets when studying piroplasms. Les espèces de Babesia sont des protozoaires parasites intraérythrocytaires qui infectent divers hôtes. Le but de cette étude était d’évaluer les espèces de piroplasmes présentes chez les mouffettes dans divers états des États-Unis et de déterminer s’il existait une variation géographique. Des rates, du sang total ou du sang sur papier filtre ont été reçus de Pennsylvanie, du Kentucky, de Caroline du Nord, de Caroline du Sud, de Géorgie, du Missouri, de Louisiane, du Texas, du Kansas et de Californie, et ont été testés pour Babesia sp. Nous avons testé quatre espèces de mouffettes, dont la mouffette rayée ( Mephitis mephitis , n  = 72), la mouffette tachetée de l’Est ( Spilogale putorius , n  = 28), la mouffette tachetée de l’Ouest ( Spilogale gracilis , n  = 15) et la mouffette à nez plat ( Conepatus leuconotus, n  = 11). Un test PCR ciblant la région de l’ARNr 18S et la région cox1 a été utilisé pour déterminer si les mouffettes étaient infectées par des piroplasmes et pour des analyses phylogénétiques. Au total, 48,4 % (61/126) des mouffettes ont été testées positives pour une espèce de Babesia . Les analyses du 18S et du cox1 ont toutes deux confirmé une espèce de type Babesia microti de carnivores spécifique aux mouffettes ainsi qu’une espèce du complexe B. microti qui est phylogénétiquement unique à la fois par rapport à B. microti de l’homme et à l’espèce des carnivores. Dans l’analyse 18S, il y avait une troisième espèce de Babesia chez les mouffettes à nez plat du groupe des piroplasmes de l’ouest. Cette étude montre qu’au moins trois espèces de piroplasmes sont présentes chez les espèces de mouffettes aux États-Unis et souligne en outre l’importance des analyses phylogénétiques et de l’utilisation de plusieurs cibles génétiques lors de l’étude des piroplasmes.

Skunk amdoparvovirus (Carnivore amdoparvovirus 4, SKAV) is closely related to Aleutian mink disease virus (AMDV) and circulates primarily in striped skunks (Mephitis mephitis) in North America. SKAV poses a threat to mustelid species due to reported isolated infections of captive American mink (Neovison vison) in British Columbia, Canada. We detected SKAV in a captive striped skunk in a German zoo by metagenomic sequencing. The pathological findings are dominated by lymphoplasmacellular inflammation and reveal similarities to its relative Carnivore amdoparvovirus 1, the causative agent of Aleutian mink disease. Phylogenetic analysis of the whole genome demonstrated 94.80% nucleotide sequence identity to a sequence from Ontario, Canada. This study is the first case description of a SKAV infection outside of North America.

We tested whether striped skunks (Mephitis mephitis) in Flagstaff, Arizona, USA, could be recognized based on variation in pelage patterns and whether camera position influenced that outcome. We presented 11 volunteers with 2 sets of 24 photographs taken between 1 January and 15 February 2015, one with animals photographed from the side, the other from above. Each set of 24 photographs included 9 pairs, with each pair representing 2 different images of the same animal. Volunteers scored twice as many correct matches and 4-fold fewer false matches when photographs were taken from above. Regardless of camera position, the total number of unique skunks in each set was underestimated (83% of total from above, 75% from side), likely because some skunks had very similar pelage patterns. Our results indicate that variation in nose stripe, back stripe, dorsal and ventral tail pattern, and shape of tail can be used to recognize individual striped skunks but similarity in those characteristics among some individuals may cause total number of unique individuals to be underestimated regardless of camera orientation.

Few studies have investigated the ecology of urban striped skunks (Mephitis mephitis) despite their role as a primary rabies vector species paired with an ability to thrive in these landscapes. Information on home range, nightly movements, and habitat selection, is important for rabies management planning regarding the placement of oral rabies vaccine (ORV) baits and for management of skunk populations more generally. Our aim was to obtain baseline ecological information with an emphasis on spatial ecology of urban striped skunks in the Northern Great Plains region that is lacking in the literature. We used radio telemetry to track 22 (4 M, 18 F) skunks during September 2016 to November 2016 and March 2017 to November 2017. Size of home range using kernel density estimation with smoothing by least squares cross validation identified that male skunks (x¯\\[ x \\] = 4.36 km2, SE ± 0.79) had larger home ranges than females (x¯\\[ x \\] = 1.79 km2, SE ± 0.24). Female skunk home ranges varied by season with the largest home ranges detected during summer 2017. We found no evidence that use-availability was associated with habitat type or season among female skunks. Female skunks were more likely to be found closer to water; however, we found no association of use with road characteristics and geographic location within the study area. Targeting ORV efforts in areas near water may be warranted, but considering differences in habitat selection for skunk studies in urban areas, we caution that ORV baiting programs may not be one-size-fits-all, and a framework for effective bait placement would benefit from studies specific to the management area of interest.

•58% (18/31) of skunks presented ONRAB® baits had detectable rabies antibody by week 7 post-vaccination.•100% (25/25) of skunks administered ONRAB® per os had detectable rabies antibody by week 7 post-vaccination.•All 10 control skunks succumbed to experimental rabies virus infection.•81% (25/31) of skunks in the ONRAB® bait group survived rabies challenge.•100% (23/23) of skunks administered ONRAB® per os survived rabies challenge. Skunks are one of the most important rabies vector species in North America due to their wide geographic distribution, high susceptibility to the rabies virus, and tendency to inhabit areas around human dwellings and domestic animals. Oral vaccination is a cost-effective, socially acceptable technique often used to control rabies in terrestrial wildlife; however, control of rabies in skunks has proven especially challenging due to the lack of a vaccine effective by the oral route in this species. In this study, we examined the antibody response of captive striped skunks (Mephitis mephitis) to ONRAB® and tested the protection afforded by the vaccine against rabies virus. Thirty-one skunks were each offered one ONRAB® vaccine bait, 25 skunks were administered ONRAB® via direct instillation into the oral cavity (DIOC) and ten controls received no vaccine. A blood sample was collected from controls and vaccinates 6 weeks prior to treatment, and then 5 and 7 weeks post-vaccination (PV). A competitive ELISA was used to detect rabies antibody (RAb). Pre-vaccination sera for all skunks, and sera for all controls throughout the serology study, were negative for RAb. Fifty-eight percent (18/31) of skunks in the bait group and 100% (25/25) of skunks that received ONRAB® DIOC had detectable RAb by 7 week PV. All 10 controls succumbed to experimental rabies infection. In the group of skunks administered ONRAB® DIOC, 100% (23/23) survived challenge 247 days PV. Survival of skunks presented ONRAB® baits was 81% (25/31). In the bait group, all 18 skunks that had detectable RAb by 7 week PV survived challenge. Seven additional skunks without detectable RAb prior to week 7 PV also survived. Lack of any remarkable pathology in study animals, together with positive serology and challenge results, supports that ONRAB® is a safe and effective oral rabies vaccine for use in skunks.

Skunks are popular carnivore species kept both in zoological institutions and in households where they are hand raised as exotic pets. These small carnivores are considered the main definitive hosts of the roundworm Baylisascaris columnaris. The purpose of this survey was to investigate the occurrence of Baylisascaris spp. in striped skunks kept as pets or in private zoo collections in some European areas. Copromicroscopic data from two laboratories, one in Italy and one in Germany, were used. A total of 60 animals were selected. Samples came from Germany (n = 30), Italy (n = 23), United Kingdom (n = 5), Austria (n = 1), and the Netherlands (n = 1). Twenty-eight animals were certainly kept as pets in private households in Italy and the UK. Fifteen out of 60 animals (25%) were positive for Baylisascaris spp. Molecular identification of adult parasites was performed in ten of those animals, revealing B. columnaris in all cases. To the authors’ knowledge, this is the first survey of Baylisascaris spp. in captive skunks in Europe.

Predicting the geographic spread of wildlife epidemics requires knowledge about the movement patterns of disease hosts or vectors. The field of landscape genetics provides valuable approaches to study dispersal indirectly, which in turn may be used to understand patterns of disease spread. Here, we applied landscape genetic analyses and spatially explicit models to identify the potential path of raccoon rabies spread in a mesocarnivore community. We used relatedness estimates derived from microsatellite genotypes of raccoons and striped skunks to investigate their dispersal patterns in a heterogeneous landscape composed predominantly of agricultural, forested and residential areas. Samples were collected in an area covering 22 000 km2 in southern Québec, where the raccoon rabies variant (RRV) was first detected in 2006. Multiple regressions on distance matrices revealed that genetic distance among male raccoons was strictly a function of geographic distance, while dispersal in female raccoons was significantly reduced by the presence of agricultural fields. In skunks, our results suggested that dispersal is increased in edge habitats between fields and forest fragments in both males and females. Resistance modelling allowed us to identify likely dispersal corridors used by these two rabies hosts, which may prove especially helpful for surveillance and control (e.g. oral vaccination) activities.