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Interspecific interactions can mediate site occupancy of sympatric species and can be a key factor in habitat use patterns. American martens (Martes americana) and Fishers (Pekania pennanti) are two sympatric mesocarnivores in eastern North American forests. Due to their larger size, fishers have a competitive advantage over martens. We investigated site occupancy of martens and fishers in temperate deciduous forests of Québec, an environment modified by forest management and climate change. We formulated hypotheses on the spatial distribution of the studied species based on the knowledge of local trappers and on the scientific literature regarding forest cover composition, habitat fragmentation, and competitive relationships. We used a network of 49 camera traps monitored over two fall seasons to document site occupancy by both species. We used two-species site occupancy models to assess habitat use and the influence of fishers on martens at spatial grains of different sizes. None of the habitat variables that we considered explained site occupancy by fishers. Availability of dense old coniferous stands explained the spatial distribution of martens both at the home range grain size and at the landscape grain size. We identified the characteristics of habitat hotspots based on the knowledge of trappers, which highlighted the importance of stand composition, height, age, and canopy closure. The characteristics of habitat hotspots for martens in temperate deciduous forests refine the habitat suitability model for American martens that was originally developed for boreal forests of Québec. [ABSTRACT FROM AUTHOR]

Weasels are small mustelid carnivores that play an important role as predators of small mammals in a wide array of ecosystems. However, their response to land use, such as forest harvest for timber products, is seldom the subject of focused research and management projects. Both the American ermine, also known as the short-tailed weasel (Mustela richardsonii), and the long-tailed weasel (Neogale frenata) are native to Maine, United States, where commercial timber harvesting is widespread. The effects of this forest disturbance on weasels are poorly understood, so to contribute toward filling this knowledge gap, we conducted a 4-year, large-scale field study: specifically, our objective was to assess the effects of forest disturbance caused by timber harvest on occupancy patterns of ermines and long-tailed weasels occupancy patterns in Maine. We collected data from 197 survey sites (three camera traps each) over 4 years and analyzed over 7,000 images of weasels using dynamic false-positive occupancy models. We found that American ermines were widely distributed across the state (naïve occupancy at 54% of sites), while long-tailed weasels were rarer (naïve occupancy at 16% of sites). Both species responded positively to forest disturbance, with higher occupancy probabilities as disturbance increased, especially at the larger scales. American ermines were more likely to occupy stands with a higher percentage of conifer trees, while no such relationship was found for long-tailed weasels. We conclude that current forest harvest practices in Maine are not detrimental to weasel populations, but that the two species warrant continued monitoring. [ABSTRACT FROM AUTHOR]

Carnivores face important anthropogenic threats in agricultural areas from habitat loss and fragmentation, disturbance by domestic free-roaming dogs and cats, and direct hunting by humans. Anthropogenic disturbances are shifting the activity patterns of wild animals, likely modifying species interactions. We estimated changes in the activity patterns of the mesocarnivore guild of agricultural landscapes of the La Araucanía region in southern Chile in response to land-use intensification, comparing intra- and interspecific activity patterns at low and high levels of forest cover, fragmentation, and land ownership subdivision. Our focal species comprise the güiña or kod-kod (Leopardus guigna), two fox species (Lycalopex culpaeus and L. griseus), a skunk (Conepatus chinga), and one native mustelid (Galictis cuja), in addition to free-roaming dogs (Canis lupus familiaris) and cats (Felis catus) and their main mammalian prey species (i.e. Rodentia and Lagomorpha). In 23,373 trap nights, we totaled 21,729 independent records of our focal species. Our results show tendencies toward nocturnality at high land-use intensification, with potential impacts on species fitness. Nocturnal mesocarnivores decreased their diurnal/crepuscular activity, while cathemeral activity shifted to nocturnal activity at high land-use intensification, but only when in sympatry with a competitor. High land-use intensification decreased the activity overlap between native and domestic mesocarnivores but increased the overlap between native mesocarnivores. High intensification also reduced overlap with prey species. Notably, foxes displayed peaks of activity opposing those of dogs, and plasticity in activity pattern when in sympatry with dogs, such as strategies to avoid encounters. We stress the need to suppress the free-roaming and unsupervised activity of dogs to mitigate impacts of high land-use intensification on mesocarnivores. [ABSTRACT FROM AUTHOR]

Coexistence of sympatric felids is facilitated by mutual avoidance and the partitioning of habitats, prey, and time. Anthropogenic disturbances disrupt this coexistence in fragmented landscapes, potentially triggering cascading influences in ecological communities. We used photographic data from 8,717 trap nights (November 2014–June 2016) at 87 camera trap sites in Colombia's middle Magdalena River basin to compare spatiotemporal overlap among jaguars (Panthera onca), pumas (Puma concolor), their prey, and humans, at sites of high and low disturbance, as determined by the human influence index. Human disturbance events (e.g. domestic dogs, livestock, and humans, including armed hunters) comprised 38% of all photographs at high disturbance sites and 29% of all photographs at low disturbance sites. Differential spatiotemporal overlaps were recorded between felids and their prey at high versus low disturbance sites, with jaguars exhibiting only 13% temporal overlap with humans at high disturbance sites. Among prey, temporal overlap was greater than spatial overlap for both felids across the study area. Compared to jaguars, pumas displayed more temporal overlap with all anthropogenic variables and more spatial overlap with most anthropogenic variables, suggesting lesser sensitivity to human disturbances. This study provides the first insights into the responses of a threatened large carnivore, jaguar, to camera trap-derived human disturbance variables in an unprotected landscape. It also highlights the importance of using multiple disturbance types for evaluating human impacts on large carnivores. [ABSTRACT FROM AUTHOR]

The rise of the Panamanian Isthmus 3–4 million years ago enabled the first dispersal of mammals between North and South America in what is known as the Great American Biotic Interchange. Modern deforestation threatens the historic forest connectivity and creates new habitat for open-country species, as documented by recent expansions of North American coyotes (Canis latrans) and South American crab-eating foxes (Cerdocyon thous) into Central America. We used camera traps to map the expansions of these species into eastern Panama and found that, by 2015, coyote populations had colonized most agricultural area west of Lago Bayano. Most of our camera arrays east of this point documented crab-eating foxes, and evidence from roadkills showed some foxes had advanced farther west, but we never documented both species at the same camera-trap array, suggesting the possibility of fine-scale spatial avoidance. We used a data fusion approach to build species distribution models combining our camera surveys with records from the literature and roadkill. While the auxiliary data improved the predictive accuracy for both species, few clear habitat patterns emerged, which might reflect the generalist tendencies of these canids, or the fact that both are in the early stages of colonizing the region. Camera-trap photos showed that both species were nocturnal and revealed some dog-like morphology in coyotes, which could indicate their recent hybridization with dogs (Canis familiaris). Our continued monitoring of the Darién documented single coyotes moving through the western edge of the area in 2016 and 2018. This leaves only the great Darién forests between coyotes and South America. If deforestation continues in the region, these two invasive canids could represent the first of a new, Not-So-Great American Biotic Interchange, where generalist species adapted to human disturbance cross continents and threaten native biota. [ABSTRACT FROM AUTHOR]

Species richness and species-specific occupancy are key variables for biodiversity monitoring. While there are many field techniques to assess presence of mammalian species, their relative performance and cost effectiveness can be affected by biological variables that are related to availability (relative abundance, diurnal activity) or by traits that are related to visibility (body size, coloration, habitat selection) of a species. We conducted four transect surveys, driven during daytime hours and continuous monitoring with camera traps over a 16-week period in Lake Manyara National Park, Tanzania. Transect and camera-trap surveys yielded estimates of 20 and 38 mammalian species, respectively. In absolute terms, diurnal vehicle transects were less costly than camera trapping, but in relative terms (cost/species), camera trapping was more cost effective. Logistic regression showed that mammal species with reduced availability (low relative abundance and low proportion of diurnal activity) were less likely to be detected during diurnal line-transect surveys. Species-specific detection probabilities and occupancy estimates were lower during transect surveys compared to the camera-trap survey. Similar to differences in naive species occupancy, method-related differences in modeled detection probabilities were positively correlated with relative abundance. Results suggest that factors influencing availability of a species explain method-related differences in detection probabilities and species richness estimates. [ABSTRACT FROM AUTHOR]

The Madrean sky islands of North America, in southern Arizona and adjacent Sonora, harbor a great diversity of vertebrates, but data about the distribution and abundance of mammal species in this region are needed to develop strategies for their management and conservation. We used camera traps to record medium and large mammals in 4 sky islands in the state of Sonora, Mexico. We compared species richness and diversity of the 25 species detected: 1) within and outside a natural protected area; 2) according to land use (natural protected area, private property, or conservation area); 3) according to the presence or absence of cattle; and 4) among 7 monitored sites. We found no differences in richness, diversity, and composition of species in our comparative analyses, suggesting homogeneity of the communities. This homogeneity could be the result of the direct or indirect influences of past human impacts in the region, given that federal protection, type of land use, and ranching did not influence the community of medium and large mammals. We discuss the importance of maintaining sites dedicated exclusively to conservation in the region, as well as promoting management at unprotected sites to make predators compatible with livestock and agricultural production. [ABSTRACT FROM AUTHOR]

The importance of a frugivore's behavior and movement on seed dispersal patterns, although widely recognized, is sometimes difficult to obtain. This is particularly true for small and nocturnal animals that inhabit structurally complex environments, such as Dromiciops gliroides. We studied different behavioral traits of this species in its natural environment during the fruiting season of the mistletoe Tristerix corymbosus. Using videos recorded by camera traps, we obtained data regarding activity levels, time allocation, feeding patterns, and movement velocities of this frugivore. Our results showed that this small marsupial seemed to avoid moonlight, and to balance the costs generated by feeding during brightest nights (i.e., when more conspicuous to predators) feeds at higher rates than during less-illuminated nights. Feeding pattern analyses showed that D. gliroides can consume between 1 and 10 fruits per plant, but generally consumes 3 fruits. We also observed that the mean time needed for D. gliroides to extract and manipulate a fruit was 6 s. Time allocation analyses showed that, on average, individuals stayed on T. corymbosus and its hosts for 55 s, and allocate most of that time on feeding and moving within the mistletoe. Video analyses were demonstrated to be a useful sampling technique, which, in addition to allowing us to obtain information about activity patterns, also permitted us to assess fruit consumption patterns, visit lengths, and time allocation when visiting mistletoe. Moreover, video allowed us to understand the variability of movement velocities under different behavioral states. The information we provide here could be included into models to simulate seed dispersal in a more realistic and accurate way that incorporates not only spatial distribution of resources, but also detailed behavioral information of frugivores. [ABSTRACT FROM AUTHOR]

Interspecific interactions can mediate site occupancy of sympatric species and can be a key factor in habitat use patterns. American martens ( Martes americana ) and Fishers ( Pekania pennanti) are two sympatric mesocarnivores in eastern North American forests. Due to their larger size, fishers have a competitive advantage over martens. We investigated site occupancy of martens and fishers in temperate deciduous forests of Québec, an environment modified by forest management and climate change. We formulated hypotheses on the spatial distribution of the studied species based on the knowledge of local trappers and on the scientific literature regarding forest cover composition, habitat fragmentation, and competitive relationships. We used a network of 49 camera traps monitored over two fall seasons to document site occupancy by both species. We used two-species site occupancy models to assess habitat use and the influence of fishers on martens at spatial grains of different sizes. None of the habitat variables that we considered explained site occupancy by fishers. Availability of dense old coniferous stands explained the spatial distribution of martens both at the home range grain size and at the landscape grain size. We identified the characteristics of habitat hotspots based on the knowledge of trappers, which highlighted the importance of stand composition, height, age, and canopy closure. The characteristics of habitat hotspots for martens in temperate deciduous forests refine the habitat suitability model for American martens that was originally developed for boreal forests of Québec., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Mammalogists.)

Knowing the factors that affect the abundance and activity patterns of pumas (Puma concolor) in South American forests may help in their conservation. Using camera traps, we conducted 4 surveys in 3 areas with different levels of protection against poaching and logging within the biggest continuous fragment of the Upper Parana Atlantic Forest. We used capture--mark--recapture population models to estimate the density of pumas for each area. The core area of Iguazú National Park, with low poaching pressure and no logging for > 60 years, had the highest density of pumas (between 1.55 and 2.89 individuals/100 km²). Yabotí Biosphere Reserve, an area with the highest poaching and logging pressure, showed the lowest density (between 0.3 and 0.74 individuals/100 km²). Areas with intermediate levels of poaching and logging pressure had densities between 0.66 and 2.19 individuals/100 km². Puma activity peaked during the 1st hours of morning in the most protected area, but became more crepuscular and nocturnal in areas with less protection. The lower abundance of pumas in the more degraded areas may be related to lower prey abundance. Differences in activity patterns of pumas among areas with different poaching pressures may be a direct response to poaching or to changes in the availability and activity patterns of primary prey. Conservation efforts should focus on decreasing poaching and logging pressures within protected areas to benefit pumas and other endangered species in the Atlantic Forest. [ABSTRACT FROM AUTHOR]

Estimates of abundance are extremely valuable for species conservation, yet determining abundance for elusive, wide-ranging, carnivores is difficult. We estimated density of pumas using remote cameras across study sites in Bolivia, Argentina, and Belize. We used obvious and subtle markings to identify individual pumas in photographs and conducted double-blind identifications to examine the degree of agreement among investigators. Average agreement on identification between pairs of investigators was nearly 80.0% and 3-way agreement was 72.9%. Identification of pumas as different individuals was uncommon (7.8% pairwise, 0.69% 3-way disagreement) with the remainder described as unidentifiable. Densities of pumas varied consistently from site to site regardless of investigator. Bolivian pumas moved the shortest distances between camera stations and Argentinean pumas the longest, but distances among cameras and area covered by surveys varied among sites. We applied a correction factor to the Bolivian data to account for the small area surveyed and found that, averaged across investigator, Bolivia had significantly more pumas per 100 km² (mean ± SD; 6.80 ± 1.5) than Belize (3.42 ± 1.3) or Argentina (0.67 ± 0.2). Numbers of pumas in Argentina match those of low-density North American sites, and those for Belize are consistent with the Pantanal and high-density North American sites. Densities of pumas can be reliably estimated with remote cameras for these sites, and our work presents the 1st density estimates for Central America and for forested environments in South America. [ABSTRACT FROM AUTHOR]