Monitoring wild animal communities with arrays of motion sensitive camera traps

Studying animal movement and distribution is of critical importance to addressing environmental challenges including invasive species, infectious diseases, climate and land-use change. Motion sensitive camera traps offer a visual sensor to record the presence of a broad range of species providing location -specific information on movement and behavior. Modern digital camera traps that record video present new analytical opportunities, but also new data management challenges. This paper describes our experience with a terrestrial animal monitoring system at Barro Colorado Island, Panama. Our camera network captured the spatio-temporal dynamics of terrestrial bird and mammal activity at the site - data relevant to immediate science questions, and long-term conservation issues. We believe that the experience gained and lessons learned during our year long deployment and testing of the camera traps as well as the developed solutions are applicable to broader sensor network applications and are valuable for the advancement of the sensor network research. We suggest that the continued development of these hardware, software, and analytical tools, in concert, offer an exciting sensor-network solution to monitoring of animal populations which could realistically scale over larger areas and time spans

Monitoring wild animal communities with arrays of motion sensitive camera traps

Studying animal movement and distribution is of critical importance to addressing environmental challenges including invasive species, infectious diseases, climate and land-use change. Motion sensitive camera traps offer a visual sensor to record the presence of a broad range of species providing location -specific information on movement and behavior. Modern digital camera traps that record video present new analytical opportunities, but also new data management challenges. This paper describes our experience with a terrestrial animal monitoring system at Barro Colorado Island, Panama. Our camera network captured the spatio-temporal dynamics of terrestrial bird and mammal activity at the site - data relevant to immediate science questions, and long-term conservation issues. We believe that the experience gained and lessons learned during our year long deployment and testing of the camera traps as well as the developed solutions are applicable to broader sensor network applications and are valuable for the advancement of the sensor network research. We suggest that the continued development of these hardware, software, and analytical tools, in concert, offer an exciting sensor-network solution to monitoring of animal populations which could realistically scale over larger areas and time spans

Tasa de registros fotográficos con cámaras trampa en caminos vs. fuera de ellos: la ubicación es importante

Tasa de registros fotográficos con cámaras trampa en caminos vs. fuera de ellos: la ubicación es importante. Presentamos los resultados de muestreos con cámaras trampa que realizamos en el Parque Nacional Iguazú, Misiones, Argentina, en 2008 para evaluar si ubicar las cámaras trampa en caminos o senderos o fuera de ellos afecta el ensamble de mamíferos muestreado. Siete pares de estaciones estuvieron activas durante 26.6 ± 8.9 días. Una estación de cada par estuvo ubicada en un camino de tierra angosto y no transitado; la otra a 50 m de distancia perpendicular del camino dentro del bosque. Usamos los registros de otro muestreo con cámaras trampa realizado en el parque nacional Iguazú en 2006-2007 para evaluar si las especies con una mayor proporción de fotos caminando sobre los senderos en lugar de cruzándolos transversal o tangencialmente (índice de uso de senderos) fueron relativamente más registradas en las estaciones ubicadas en senderos en 2008. Usamos el estimador Jackknife de primer orden para comparar la riqueza de especies en estaciones de senderos y fuera de ellos. Un ANOVA multivariado basado en disimilitudes (ADONIS) fue usado para comparar los ensambles de mamíferos registrados en caminos y fuera de ellos. Obtuvimos 228 registros independientes de 15 especies de mamíferos terrestres medianos-grandes. Las estaciones ubicadas en caminos tuvieron una mayor tasa de registros (1.06±0.57 vs. 0.24±0.13 registros/día) y una mayor riqueza que las estaciones fuera de ellos (15 vs. 10 especies observadas; 19.3, SE=2.8 vs. 14.3, SE=2.8 especies estimadas con el modelo Jackknife de 1er orden). Las especies difirieron en sus probabilidades relativas de ser registradas en caminos vs fuera de ellos, algo que puede predecirse a partir del índice de uso de senderos. El ADONIS indicó que el ensamble de mamíferos muestreado en caminos fue estadísticamente distinto al muestreado fuera de ellos, un resultado que puede ser explicado por la tendencia diferencial de las especies a usar los caminos.We present the results of a camera trap survey conducted in 2008 in the Atlantic Forest of Iguazú National Park, Argentina, testing whether placing camera traps on dirt roads/ trails or in off-road locations produce important biases in the recorded species. Seven pairs of camera trap stations were active for 26.6 ± 8.9 days; for each pair, one station was located on a narrow unpaved road and the other about 50 m from the road. We used the first order Jackknife estimator to compare species richness between on-road vs. off-road locations. We used records from another camera trap survey conducted at Iguazú National Park in 2006-2007 to assess whether species with a high Road-use Index (ratio of photographs of animals walking along roads to photographs of animals crossing the roads) had a higher ratio of records on roads / off road stations in the 2008 survey. Multivariate ANOVA based on dissimilarities (ADONIS) was used to compare mammal assemblages recorded at stations located on roads vs. off roads. We obtained 228 independent records of 15 species of medium-large sized terrestrial mammals. Stations located on roads had a higher recording rate (1.06, SD=0.57 vs. 0.24, SD=0.13 records per day) and recorded more species than off-road stations (15 vs. 10 recorded species; 19.3, SE=2.8 vs. 14.3, SE=2.8 species estimated with the 1st order Jackknife model). Species differ in their relative probabilities of being recorded on roads vs. off roads, something that can be predicted with the Road-use Index. The ADONIS indicated that the mammal assemblage surveyed on roads was statistically dissimilar to that surveyed off roads, a result that can be explained by the differential tendency of the species to use roads and trails.Fil: Di Bitetti, Mario Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Forestales; ArgentinaFil: Paviolo, Agustin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Asociación Civil Centro de Investigaciones del Bosque Atlántico; ArgentinaFil: de Angelo, Carlos Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentin

An empirical evaluation of camera trap study design: How many, how long and when?

Abstract Camera traps deployed in grids or stratified random designs are a well‐established survey tool for wildlife but there has been little evaluation of study design parameters. We used an empirical subsampling approach involving 2,225 camera deployments run at 41 study areas around the world to evaluate three aspects of camera trap study design (number of sites, duration and season of sampling) and their influence on the estimation of three ecological metrics (species richness, occupancy and detection rate) for mammals. We found that 25–35 camera sites were needed for precise estimates of species richness, depending on scale of the study. The precision of species‐level estimates of occupancy (ψ) was highly sensitive to occupancy level, with 0.75) species, but more than 150 camera sites likely needed for rare (ψ < 0.25) species. Species detection rates were more difficult to estimate precisely at the grid level due to spatial heterogeneity, presumably driven by unaccounted habitat variability factors within the study area. Running a camera at a site for 2 weeks was most efficient for detecting new species, but 3–4 weeks were needed for precise estimates of local detection rate, with no gains in precision observed after 1 month. Metrics for all mammal communities were sensitive to seasonality, with 37%–50% of the species at the sites we examined fluctuating significantly in their occupancy or detection rates over the year. This effect was more pronounced in temperate sites, where seasonally sensitive species varied in relative abundance by an average factor of 4–5, and some species were completely absent in one season due to hibernation or migration. We recommend the following guidelines to efficiently obtain precise estimates of species richness, occupancy and detection rates with camera trap arrays: run each camera for 3–5 weeks across 40–60 sites per array. We recommend comparisons of detection rates be model based and include local covariates to help account for small‐scale variation. Furthermore, comparisons across study areas or times must account for seasonality, which could have strong impacts on mammal communities in both tropical and temperate sites

Mammal communities are larger and more diverse in moderately developed areas

Developed areas are thought to have low species diversity, low animal abundance, few native predators, and thus low resilience and ecological function. Working with citizen scientist volunteers to survey mammals at 1427 sites across two development gradients (wild-rural-exurban- suburban-urban) and four plot types (large forests, small forest fragments, open areas and residential yards) in the eastern US, we show that developed areas actually had significantly higher or statistically similar mammalian occupancy, relative abundance, richness and diversity compared to wild areas. However, although some animals can thrive in suburbia, conservation of wild areas and preservation of green space within cities are needed to protect sensitive species and to give all species the chance to adapt and persist in the Anthropocene. DOI: https://doi.org/10.7554/eLife.38012.00

a standardized assessment of forest mammal communities reveals consistent functional composition and vulnerability across the tropics

Understanding global diversity patterns has benefitted from a focus on functional traits and how they relate to variation in environmental conditions among assemblages. Distant communities in similar environments often share characteristics, and for tropical forest mammals, this functional trait convergence has been demonstrated at coarse scales (110-200 km resolution), but less is known about how these patterns manifest at fine scales, where local processes (e.g., habitat features and anthropogenic activities) and biotic interactions occur. Here, we used standardized camera trapping data and a novel analytical method that accounts for imperfect detection to assess how the functional composition of terrestrial mammal communities for two traits – trophic guild and body mass – varies across 16 protected areas in tropical forests and three continents, in relation to the extent of protected habitat and anthropogenic pressures. We found that despite their taxonomic differences, communities generally have a consistent trophic guild composition, and respond similarly to these factors. Insectivores were found to be sensitive to the size of protected habitat and surrounding human population density. Body mass distribution varied little among communities both in terms of central tendency and spread, and interestingly, community average body mass declined with proximity to human settlements. Results indicate predicted trait convergence among assemblages at the coarse scale reflects consistent functional composition among communities at the local scale, suggesting that broadly similar habitats and selective pressures shaped communities with similar trophic strategies and responses to drivers of change. These similarities provide a foundation for assessing assemblages under anthropogenic threats and sharing conservation measures.Understanding global diversity patterns has benefitted from a focus on functional traits and how they relate to variation in environmental conditions among assemblages. Distant communities in similar environments often share characteristics, and for tropical forest mammals, this functional trait convergence has been demonstrated at coarse scales (110-200 km resolution), but less is known about how these patterns manifest at fine scales, where local processes (e.g., habitat features and anthropogenic activities) and biotic interactions occur. Here, we used standardized camera trapping data and a novel analytical method that accounts for imperfect detection to assess how the functional composition of terrestrial mammal communities for two traits – trophic guild and body mass – varies across 16 protected areas in tropical forests and three continents, in relation to the extent of protected habitat and anthropogenic pressures. We found that despite their taxonomic differences, communities generally have a consistent trophic guild composition, and respond similarly to these factors. Insectivores were found to be sensitive to the size of protected habitat and surrounding human population density. Body mass distribution varied little among communities both in terms of central tendency and spread, and interestingly, community average body mass declined with proximity to human settlements. Results indicate predicted trait convergence among assemblages at the coarse scale reflects consistent functional composition among communities at the local scale, suggesting that broadly similar habitats and selective pressures shaped communities with similar trophic strategies and responses to drivers of change. These similarities provide a foundation for assessing assemblages under anthropogenic threats and sharing conservation measures

Analysis of Variables Related to Corridor Use by Ocelots and Bobcats in South Texas

Biologists estimate that less than 50 endangered ocelots (Leopardus pardalis) remain in the United States, restricted to two small populations in Cameron and Willacy Counties located in deep south Texas. Conversely, bobcats (Lynx rufus) are abundant in south Texas; however, two of the biggest threats to both species are vehicle collisions and habitat fragmentation. To mitigate these threats, the installation of wildlife crossings has been proposed to decrease the number of road mortalities, and wildlife corridors have been suggested as a useful tool for providing increased habitat connectivity. However, research on ocelot use of corridors and wildlife crossings in Texas is severely lacking. Due to overlap in daily activity, diet, and habitat, ocelots and bobcats may be exhibiting competition over resources where space to coexist without conflict is limited. This study used camera traps to document wildlife communities with a focus on ocelots and bobcats from October 2013 to October 2014 to test the following hypotheses: 1) Bobcat hourly activity will differ between locations where ocelots are present and absent. 2) Prey composition will be a significant indicator of felid presence. 3) Ocelot and bobcat presence will be correlated with differing plant species and levels of canopy cover. 4) Wildlife diversity indices will be similar within corridor types and will differ between corridor types. 5) Wildlife community composition and diversity indices will differ between proposed wildlife crossings and corridors not adjacent to Farm-to-Market Road (F.M.) 106. Cameras were placed within four structural habitat types: brush strip, resaca (oxbow lake) edge, drainage ditch, and brush patch. Structural habitat variables were surveyed to analyze habitat preferences of ocelots and bobcats in corridors. Fifty-eight species were identified at 52 cameras. Eight of the 16 known ocelots in the Cameron County population were surveyed. Bobcat hourly activity and prey frequency were different at cameras where ocelots were present and absent. Ocelots were associated with corridors (brush strip, resaca edge, drainage ditch) and not brush patches; high amounts of spiny hackberry, texas ebony, and goatbush; greater distance from F.M. 106; higher diversity of woody species \u3e1m tall; and ground cover comprised of low amounts of grass, forbs, and bare ground, and high amounts of leaf litter, woody debris, and woody speciessmall, sparse brush patches in wildlife frequency and diversity, and brush strips had the greatest species richness and total number of individuals. Brush patches had a significantly lower number of individuals present when compared to corridors. Fifty percent of the known Cameron County ocelot population was observed using corridors, suggesting that functional corridors may be a valuable tool to promote connectivity of ocelot populations in Texas. Proposed wildlife crossing locations had lower diversity when compared to corridors not adjacent to F.M. 106. However, ocelots were recorded on both sides of F.M. 106, indicating that wildlife crossing structures under roadways should be effective in providing ocelots with a safe alternative to traversing over dangerous roadways

Forest Disturbance and Occupancy Patterns of Carnivores: Results of a Large-scale Field Study in Maine, USA

Understanding trends in the abundance and distribution of carnivores is important at global, regional and local scales due to their ecological role, their aesthetic and economic value, and the numerous threats to their populations. Carnivores in Maine range from the American black bear (Ursus americanus), to numerous native mesocarnivore species, such as American marten (Martes americana), fisher (Pekania pennanti), coyote (Canis latrans), red fox (Vulpes vulpes), bobcat (Lynx rufus), Canada lynx (Lynx canadensis) and to two small weasel species (Mustela erminea and Neogale frenata). Though smaller than their apex carnivore cousins, Mesocarnivores are essential components of ecosystems and have complex impacts on prey species and intraguild dynamics. However, these species can vary in how they respond to human disturbances, from direct declines due to unregulated harvest and habitat loss, and their ability to adapt to land-use change. Maine is a working landscape which provides habitat for diverse wildlife species coincident with extensive forest harvest industries, as well as tourism and recreation. The intensity, timing, and configuration of harvest activities all interact to modify the landscape, with cascading impacts on the distribution of many animals. Forest management practices have changed through time (Maine Forest Service 2003) with potentially unpredictable outcomes (e.g. Simons 2009). However, the extent to which carnivore species adapt to land use change is a key knowledge gap that needs to be addressed to ensure proper management and conservation going forward. I investigated these patterns by designing a natural experiment across the forested landscape of Maine, and by collecting detection data on multiple species at camera trapping survey stations deployed along a gradient of forest disturbance. My dissertation aims to collect broad-scale, relevant information for carnivore management and conservation, and assess the efficacy of motion-triggered trail cameras for long-term monitoring. My work is divided into four sections, reflected by the four chapters included in the dissertation. My first goal was to determine the optimal number and configuration of camera-trap transects, to balance between reasonable effort expended and high-quality data collection. I used multi-method occupancy analyses to compare between one, two or three camera units spaced either 100 m or 150 m apart. We found that a design with three cameras spaced 100 m apart increased detection probabilities up to five-fold over a single camera trap, and thus used this configuration for the duration of the following research. Once the survey unit was selected, I established a large-scale, multi-year camera trapping regimen across the northern two-thirds of Maine. Survey sites were selected in compliance with a natural experimental design, replicating across all combinations of a) forest disturbance intensity, b) latitude, and c) fur trapping harvest reports for key furbearing species. In the second chapter I present this study design in more detail, and use the resulting data to investigate the interspecies dynamics of marten and fisher, two species of interest to the state of Maine that co-exist in several geographic areas and partition habitat in distinct ways. Both species are sensitive to habitat change resulting from timber harvest, which was a more important factor in occupancy patterns than intraguild dynamics. In chapter three, I took advantage of the large data set I collected to provide a landscape scale understanding of long-tailed and short-tailed weasel distribution patterns in the face of habitat change. Both of these species are poorly studied, and may be in decline in North American. My results indicate that short-tailed weasel are widespread in Maine and do not appear limited by forest harvest practices, while long-tailed weasel are rarer and more apt to be present in southern Maine. Finally in chapter four I ran models incorporating multiple states for species occupancy, beyond mere present or absent, to understand the dynamics of black bears and of black bear reproduction across managed forests in Maine. I found that generally disturbance at a small scale was positively associated with both occupancy and probability of reproduction, while the availability of hardwood trees (an important food source for bears) was also positively linked to the probability of female bears being with cubs. In addition to meeting our stake holder needs for informed management guidelines, I hope that many of my findings will be directly relevant to the broader research community—as camera trapping equipment becomes more affordable, it will become feasible to both monitor and rigorously study wildlife populations in remote locations and under many scenarios of human land-use

Quantifying Mammalian Interactions and Distributions to Inform Conservation Planning in Mozambique

Protected areas are a staple in conservation, but human activities outside of protected areas drive species interactions, compositions, and distributions. Research is especially needed in these multi-use landscapes to maintain habitat connectivity for entire wildlife communities between protected areas. Yet, such research is lacking in areas it is needed most, such as in sub-Saharan Africa, where human populations are expected to double by 2050. My objectives were to quantify mammal distributions, interactions, community compositions, and their relationships with human and natural factors within a sustainable-use forestry concession outside of Gorongosa National Park. I used recently developed multispecies occupancy models to analyze presence/absence data from 75 motion-detecting camera traps. First, I wanted to know if small, sympatric carnivores avoided each other in time or space in a human-modified landscape with few apex predators. I examined activity patterns, habitat preferences, tolerance to people and potential for intraguild competition among three common, but understudied African carnivores: African civets (Civettictis civetta), bushy-tailed mongoose (Bdeogale crassicauda), and large-spotted genets (Genetta maculata). I hypothesized that all three species would overlap in time, but in space, genets and mongoose would both avoid civets due to being smaller; and genets and mongoose, being roughly the same size, would not affect each other. I used the time stamps from each species’ detections and found that these three species exhibited strong temporal overlap. I then used N-mixture models in a Bayesian framework to measure these species’ spatial relationships. I found that civets and mongoose avoid each other, indicated by the strong negative relationship between their predicted abundances at each camera trap site. In contrast, genets and mongoose exhibited a positive relationship, and there was no significant relationship between genets and civets. Civets and mongoose may be further limited in space through the avoidance of human settlements if they are also competing with each other, while genets were unaffected by human presence. Such interspecific interactions are important to consider for multispecies conservation planning in multi-use landscapes, as these relationships may change as human populations grow. Second, I investigated how natural and anthropogenic factors influence animal space use and richness in a multi-use area. We used hierarchical, multispecies models to quantify species and species groups, and community level spatial relationships with human and environmental variables for 30 detected mammals. We modelled species occupancies when separated into two different groups: 1) taxonomic/functional groups consisting of carnivores, ungulates, primates, other foragers, and insectivores, and 2) body size groups, consisting of small species (200kg). We also quantified occupancy probabilities and richness for the entire community to determine where species richness was greatest and inform biodiversity conservation efforts. We predicted that carnivores and large mammals would be the most sensitive to anthropogenic features. In partial support of this hypothesis, increasing distance from settlements positively affected the occupancies of carnivores, as well as primates and other foragers, and large mammals, as well as all three of the other body size groups. However, active roads and human activity rates did not have a statistically significant relationship with any species’ occupancies or detection rates, respectively. Overall, mammalian richness was highest far from human settlements in the concession and close to rivers. Our results have important implications for connectivity planning for multispecies conservation outside of Gorongosa National Park, and provide a starting point for prioritizing these efforts

Influence of Landscape Factors on Wildlife Presence and Road Mitigation Structure Performance

There are roughly 80 ocelots (Leopardus pardalis) remaining in the United States, with the entire population constrained to south Texas, with roadkill being a predominant source of mortality. To prevent additional roadkill and maintain wildlife movement, Texas Department of Transportation constructed 11.9 kilometers of wildlife exclusion fencing, 5 wildlife crossing structures (WCS), and 18 wildlife guards on State Highway 100. This thesis focused on determining the effort required for a control-impact monitoring study, the influence of biotic and abiotic factors around the roadway on wildlife presence, and the performance of mitigation structures and the road mitigation corridor. This research shows that control-impact studies are important for road ecology projects and their design strongly influences survey effort. Additionally, felid presence is likely influenced by vegetation and distance to WCS, and will most likely use WCS with a small box-culvert design