Broad scale population estimates of declining species are desired for conservation efforts. However, for many secretive species including large carnivores, such estimates are often difficult. Based on published density estimates obtained through camera trapping, presence/absence data, and globally available predictive variables derived from satellite imagery, we modelled density and occurrence of a large carnivore, the jaguar, across the species’ entire range. We then combined these models in a hierarchical framework to estimate the total population. Our models indicate that potential jaguar density is best predicted by measures of primary productivity, with the highest densities in the most productive tropical habitats and a clear declining gradient with distance from the equator. Jaguar distribution, in contrast, is determined by the combined effects of human impacts and environmental factors: probability of jaguar occurrence increased with forest cover, mean temperature, and annual precipitation and declined with increases in human foot print index and human density. Probability of occurrence was also significantly higher for protected areas than outside of them. We estimated the world’s jaguar population at 173,000 (95% CI: 138,000–208,000) individuals, mostly concentrated in the Amazon Basin; elsewhere, populations tend to be small and fragmented. The high number of jaguars results from the large total area still occupied (almost 9 million km2) and low human densities (< 1 person/km2) coinciding with high primary productivity in the core area of jaguar range. Our results show the importance of protected areas for jaguar persistence. We conclude that combining modelling of density and distribution can reveal ecological patterns and processes at global scales, can provide robust estimates for use in species assessments, and can guide broad-scale conservation actions.
Large carnivores such as jaguars (Panthera onca) are species of conservation concern because they are suffering population declines and are keystone species in their ecosystems. Their large area requirements imply that unprotected and ever-increasing agricultural regions can be important habitats as they allow connectivity and dispersal among core protected areas. Yet information on jaguar densities across unprotected landscapes it is still scarce and crucially needed to assist management and range-wide conservation strategies. Our study provides the first jaguar density estimates of Colombia in agricultural regions which included cattle ranching, the main land use in the country, and oil palm cultivation, an increasing land use across the Neotropics. We used camera trapping across two agricultural landscapes located in the Magdalena River valley and in the Colombian llanos (47–53 stations respectively; >2000 trap nights at both sites) and classic and spatially explicit capture-recapture models with the sex of individuals as a covariate. Density estimates were 2.52±0.46–3.15±1.08 adults/100 km2 in the Magdalena valley, whereas 1.12±0.13–2.19±0.99 adults/100 km2 in the Colombian llanos, depending on analysis used. We suggest that jaguars are able to live across unprotected human-use areas and co-exist with agricultural landscapes including oil-palm plantations if natural areas and riparian habitats persist in the landscape and hunting of both jaguar and prey is limited. In the face of an expanding agriculture across the tropics we recommend land-use planning, adequate incentives, regulations, and good agricultural practices for range-wide jaguar connectivity and survival.
Highlights Agriculture reduces community diversity and evenness, while increases dominance. Forests and vicinity to water increase species occupancy; pastures decrease it. Forest areas are crucial for pumas, ocelots, raccoons, pacas, and agoutis. Wetlands are important for jaguars, the apex predator. Key to maintain forests and wetlands and target future crop expansion on pastures. Abstract 1As human-modified landscapes are increasing in the tropics, it becomes critical to understand 2 how they affect mammal communities to reconcile conservation and development. We 3 combined land cover information and camera-trapping data to explore the effects of 4 agricultural expansion on mammals in the Magdalena river valley of Colombia. We estimated 5 species diversity, evenness, and dominance across two agricultural landscapes, modified by 6 cattle ranching and oil palm cultivation. We further assessed which variables influence species-7 and community-level occupancy using multi-species occupancy models. Results highlight that 8 modified landscapes display lower species richness, diversity and evenness, and higher 9 dominance than more pristine sites. Residual forest cover and distance to water had significant 10 effect on community occupancy (positive and negative respectively). Forests were particularly 11 important for pumas, ocelots, lowland pacas, Central American agoutis, and crab-eating 12 raccoons while wetlands had a positive effect on jaguars, the apex predator in the region. The 13 influence of anthropogenic pressure was not clearly evident, though pastures were not valuable 14 habitats for any mammal species, as they had a negative, yet not robust, effect on species and 15 community occupancy. In light of rapidly expanding agriculture across the tropics, our findings 16 highlight species-specific responses to disturbance that can inform land use planning and 17 conservation policies. We stress the conservation value of forest and wetland habitat to 18 mammal occupancy in heterogeneous ecosystems. Moreover, our results demonstrate that oil 19 palm and crop expansion should target existing pastures, which displayed limited conservation 20 value for Neotropical mammals but occupy vast swathes of land across Latin America. 21
Loss and degradation of natural habitats continue to increase across the tropics as a result of agricultural expansion. Consequently, there is an urgent need to understand their effects, and the distribution and habitat requirements of wildlife within human-modified landscapes, to support the conservation of threatened species, such as felids. We combined camera trapping and land cover data into occupancy models to study the habitat use and space partitioning by four sympatric felid species in an agricultural landscape in Colombia. Land use in the area includes cattle ranching and oil palm cultivation, the latter being an emerging land use type in the Neotropics. Factors determining species occupancy were the presence of wetlands for jaguars (positive effect); water proximity for pumas (positive effect); and presence of pastures for ocelots and jaguarundis (negative effect). Only ocelots were occasionally recorded in oil palm areas. Our results suggest that to align development with the conservation of top predators it is crucial to maintain areas of forest and wetland across agricultural landscapes and to restrict agricultural and oil palm expansion to modified areas such as pastures, which are of limited conservation value. Because there is no spatial segregation between the felid species we studied, conservation strategies that benefit all of them are possible even in modified landscapes.
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