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DESIGNING CORRIDORS BEFORE IT IS TOO LATE: JAGUAR HABITAT AVAILABILITY IN AN AGRICULTURE FRONTIER IN BRAZIL
The jaguar (Panthera onca) is a threatened species in Brazil, where most of the protected areas, taken individually, do not hold viable jaguar populations. The Sertão Veredas-Peruaçu Mosaic (SVPM) is a high priority region for jaguar conservation in Cerrado that comprises 15 protected areas. Although the region appears well conserved, the continued conversion of native vegetation into large monocultures, illegal charcoal production, and pasture burns might alter landscape characteristics and negatively affect local biodiversity. As the maintenance of the connectivity in the region is vital for jaguar conservation, we evaluated jaguar habitat availability and designed corridors in SVPM region. We identified suitable patches for jaguar conservation aggregating the 10% most important pixels from a map of spatial prioritization for jaguar conservation in the Cerrado, modeled previously with Maxent and Zonation, calling them jaguar patches. Then, we evaluated fine-scale (125m) habitat availability in four scenarios, combining jaguar patches in the presence or absence of strictly protected areas (SPAs). In order to characterize the landscape in the region, land cover, slope, human population density, linear distance to roads and linear distance to settlements were used to build a resistance surface. Least-cost paths and circuit theory were used to identify pinch points (areas within the corridors that have high-density current) and to delineate corridors. We calculated connectivity indices (e.g. IIC= integral index of connectivity) considering the effective resistance values of the corridors as the distance among patches with Conefor Sensinode. We selected the jaguar patches that were more important for connectivity to create the fifth scenario. The strictly protected areas-only scenario had one of the lowest connectivity values (9 patches; IIC=8,536,193; area= 3699.26 km²), overestimating the isolation among patches and underestimating habitat availability. The jaguar patches-only scenario did not provide enough habitat for a viable population in the region (30 patches; IIC=1,576,640; area= 1910.69 km²). The combination of all jaguar patches and SPAs presented higher connectivity but in an extensive area (32 patches; IIC=14,825,150; area= 5484.28 km²). We considered the fifth scenario the best as it presented a high index of connectivity with a smaller area and fewer patches (19 patches, IIC=14,032,940, area= 5085.41 km²). The region still has a vast area that can maintain a high habitat availability for jaguars, but most of them are outside SPAs. Should part of the native vegetation outside the SPAs be removed, habitat availability in the region could be reduced in 43-62%, with serious implications to the conservation of the local jaguar population. There are sustainable use protected areas in SVPM which could guarantee habitat preservation, but as most of them allow agriculture and other human economic activities that change the landscape, jaguar patches are not necessarily protected. This highlights the importance of identification and conservation of habitat patches outside protected areas before habitat loss and isolation occur. The selected jaguar patches and the corridors identified, particularly those with pinch-points, should be characterized as of high priority when establishing new protected areas in the SVPM region, in the mosaic management and regional public policies.
Panthera onca, connectivity, landscape ecology
Biologia da Conservação
Marina Peres Portugal, Flávio Henrique Guimarães Rodrigues, Claudia Maria Jacobi