Browsing by Author "Farris, Zachary J."

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    Assessing global patterns in mammalian carnivore occupancy and richness by integrating local camera trap surveys
    Rich, Lindsey N.; Davis, Courtney L.; Farris, Zachary J.; Miller, David A. W.; Tucker, Jody M.; Hamel, Sandra; Farhadinia, Mohammad S.; Steenweg, Robin; Di Bitetti, Mario S.; Thapa, Kanchan; Kane, Mamadou D.; Sunarto, Sunarto; Robinson, Nathaniel P.; Paviolo, Agustin; Cruz, Paula; Martins, Quinton; Gholikhani, Navid; Taktehrani, Atieh; Whittington, Jesse; Widodo, Febri A.; Yoccoz, Nigel G.; Wultsch, Claudia; Harmsen, Bart J.; Kelly, Marcella J. (2017-08)
    Aim: Biodiversity loss is a major driver of ecosystem change, yet the ecological data required to detect and mitigate losses are often lacking. Recently, camera trap surveys have been suggested as a method for sampling local wildlife communities, because these observations can be collated into a global monitoring network. To demonstrate the potential of camera traps for global monitoring, we assembled data from multiple local camera trap surveys to evaluate the interchange between fine- and broad-scale processes impacting mammalian carnivore communities. Location: Argentina, Belize, Botswana, Canada, Indonesia, Iran, Madagascar, Nepal, Norway, Senegal, South Africa, and the U.S.A. Methods: We gathered camera trap data, totalling >100,000 trap nights, from across five continents. To analyse local and species-specific responses to anthropogenic and environmental variables, we fitted multispecies occurrence models to each study area. To analyse global-level responses, we then fitted a multispecies, multi-area occurrence model. Results: We recorded 4,805 detections of 96 mammalian carnivore species photographed across 1,714 camera stations located in 12 countries. At the global level, our models revealed that carnivore richness and occupancy within study areas was positively associated with prey availability. Occupancy within study areas also tended to increase with greater protection and greater distances to roads. The strength of these relationships, however, differed among countries. Main conclusions: We developed a research framework for leveraging global camera trap data to evaluate patterns of mammalian carnivore occurrence and richness across multiple spatial scales. Our research highlights the importance of intact prey populations and protected areas in conserving carnivore communities. Our research also highlights the potential of camera traps for monitoring wildlife communities and provides a case study for how this can be achieved on a global scale. We encourage greater integration and standardization among camera trap studies worldwide, which would help inform effective conservation planning for wildlife populations both locally and globally.
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    Ecological correlates of the spatial co-occurrence of sympatric mammalian carnivores worldwide
    Davis, Courtney L.; Rich, Lindsey N.; Farris, Zachary J.; Kelly, Marcella J.; Di Bitetti, Mario S.; Di Blanco, Yamil; Albanesi, Sebastian; Farhadinia, Mohammad S.; Gholikhani, Navid; Hamel, Sandra; Harmsen, Bart J.; Wultsch, Claudia; Kane, Mamadou D.; Martins, Quinton; Murphy, Asia J.; Steenweg, Robin; Sunarto, Sunarto; Taktehrani, Atieh; Thapa, Kanchan; Tucker, Jody M.; Whittington, Jesse; Widodo, Febri A.; Yoccoz, Nigel G.; Miller, David A. W. (2018-09)
    The composition of local mammalian carnivore communities has far-reaching effects on terrestrial ecosystems worldwide. To better understand how carnivore communities are structured, we analysed camera trap data for 108087 trap days across 12 countries spanning five continents. We estimate local probabilities of co-occurrence among 768 species pairs from the order Carnivora and evaluate how shared ecological traits correlate with probabilities of co-occurrence. Within individual study areas, species pairs co-occurred more frequently than expected at random. Co-occurrence probabilities were greatest for species pairs that shared ecological traits including similar body size, temporal activity pattern and diet. However, co-occurrence decreased as compared to other species pairs when the pair included a large-bodied carnivore. Our results suggest that a combination of shared traits and top-down regulation by large carnivores shape local carnivore communities globally.
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    Hunting, Exotic Carnivores, and Habitat Loss: Anthropogenic Effects on a Native Carnivore Community, Madagascar
    Farris, Zachary J.; Golden, Christopher D.; Karpanty, Sarah M.; Murphy, Asia J.; Stauffer, Dean F.; Ratelolahy, Felix; Andrianjakarivelo, Vonjy; Holmes, Christopher M.; Kelly, Marcella J. (PLOS, 2015-09-16)
    The wide-ranging, cumulative, negative effects of anthropogenic disturbance, including habitat degradation, exotic species, and hunting, on native wildlife has been well documented across a range of habitats worldwide with carnivores potentially being the most vulnerable due to their more extinction prone characteristics. Investigating the effects of anthropogenic pressures on sympatric carnivores is needed to improve our ability to develop targeted, effective management plans for carnivore conservation worldwide. Utilizing photographic, line-transect, and habitat sampling, as well as landscape analyses and village-based bushmeat hunting surveys, we provide the first investigation of how multiple forms of habitat degradation (fragmentation, exotic carnivores, human encroachment, and hunting) affect carnivore occupancy across Madagascar’s largest protected area: the Masoala-Makira landscape. We found that as degradation increased, native carnivore occupancy and encounter rates decreased while exotic carnivore occupancy and encounter rates increased. Feral cats (Felis species) and domestic dogs (Canis familiaris) had higher occupancy than half of the native carnivore species across Madagascar’s largest protected landscape. Bird and small mammal encounter rates were negatively associated with exotic carnivore occupancy, but positively associated with the occupancy of four native carnivore species. Spotted fanaloka (Fossa fossana) occupancy was constrained by the presence of exotic feral cats and exotic small Indian civet (Viverricula indica). Hunting was intense across the four study sites where hunting was studied, with the highest rates for the small Indian civet (x=90 individuals consumed/year), the ring-tailed vontsira (Galidia elegans) (x=58 consumed/year), and the fosa (Cryptoprocta ferox) (x=31 consumed/year). Our modeling results suggest hunters target intact forest where carnivore occupancy, abundance, and species richness, are highest. These various anthropogenic pressures and their effects on carnivore populations, especially increases in exotic carnivores and hunting, have wide-ranging, global implications and demand effective management plans to target the influx of exotic carnivores and unsustainable hunting that is affecting carnivore populations across Madagascar and worldwide.
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    Responses of Madagascar's Endemic Carnivores to Fragmentation, Hunting, and Exotic Carnivores Across the Masoala-Makira Landscape
    Farris, Zachary J. (Virginia Tech, 2015-01-06)
    The carnivores of Madagascar are likely the least studied of the world's carnivores, thus little is known about threats to their persistence. I provide the first long-term assessment of Madagascar's rainforest carnivore community, including: 1) how multiple forms of habitat degradation (i.e., fragmentation, exotic carnivores, human encroachment, and hunting) affect native and exotic carnivore occupancy; 2) how native and exotic carnivore temporal activity overlap and how body size and niche explain these patterns; 3) how native and exotic carnivores spatially co-occur across the landscape and which variables explain these relationships; and 4) how native and exotic carnivores and humans co-occur with lemurs across Madagascar's largest protected landscape: the Masoala-Makira landscape. From 2008 to 2013 I photographically sampled carnivores and conducted line-transect surveys of lemurs at seven study sites with varying degrees of degradation and human encroachment, including repeat surveys of two sites. As degradation increased, exotic carnivores showed increases in activity and occupancy while endemic carnivore, small mammal, and lemur occupancy and/or activity decreased. Wild/feral cats (Felis sp.) and dogs (Canis familiaris) had higher occupancy (0.37 ± SE 0.08 and 0.61 ± SE 0.07, respectively) than half of the endemic carnivore species across the landscape. Additionally, exotic carnivores had both direct and indirect negative effects on native carnivore occupancy. For example, spotted fanaloka (Fossa fossana) occupancy (0.70 ± SE 0.07) was negatively impacted by both wild/feral cat (beta = -2.65) and Indian civets (beta = -1.20). My results revealed intense pressure from hunting (ex. n = 31 fosa Cryptoprocta ferox consumed per year from 2005-2011 across four villages), including evidence that hunters target intact forest where native carnivore and lemur occupancy and/or activity are highest. I found evidence of high temporal overlap between native and exotic carnivores (ex. temporal overlap between brown-tail vontsira Salanoia concolor and dogs is 0.88), including fosa (Cryptoprocta ferox) avoiding dogs and humans across all seasons. However, I found no evidence of body size or correlates of ecological niche explaining temporal overlap among carnivores. Estimates of spatial co-occurrence among native and exotic carnivores in rainforest habitat revealed strong evidence that native and exotic carnivores occur together less often than expected and that exotic carnivores may be replacing native carnivores in forests close to human settlements. For example, falanouc show a strong increase in occupancy when dogs are absent (0.69 ± SE 0.11) compared to when they are present (0.23 ± SE 0.05). Finally, the two-species interaction occupancy models for carnivores and lemurs, revealed a higher number of interactions among species across contiguous forest where carnivore and lemur occupancy were highest. These various anthropogenic pressures and their effects on carnivore and lemur populations, particularly increases in exotic carnivores and hunting, have wide-ranging, global implications and demand effective management plans to target the influx of exotic carnivores and unsustainable hunting affecting carnivore and primate populations across Madagascar and worldwide.