Densidade e uso de recursos por veado-campeiro (Ozotoceros bezoarticus) em três paisagens diferentes no Pantanal, MS

Abstract

The pampas deer, Ozotoceros bezoarticus, is a deer that is listed as Near Threatened by the IUCN. It is not known what effect the replacement for the natural pastures planted with exotic species on the population of pampas deer in the Pantanal. The objectives of this study were to verify the differences in diversity and availability of forage species, variation in the resource selection, in diet niche, in deer density and aggregation of foraging locations in three different landscapes in the Pantanal, including areas of pasture. Sixty pampas deer were captured, marked and monitored from September 2009 to October 2010, in the three landscapes. We compared the availability of plant species and diversity the Shannon-Wiener (H') and dominance (d) indexes. The variation of the pampas deer diet composition was studied through feeding site technique. The deer preference for plant species was estimated using a resource selection function and a standardized selection index. The deer density was estimated using the distance sampling technique. The locations were examined to evaluate their level of aggregation in foraging sites, bases on locations of 3 marked individuals in each study area. The landscape dominated by woodland savanna presented higher plant diversity, while the cultivated pasture presented highest dominance. The amplitude of the diet niche was larger in the floodable grasslands than in the savanna landscape. The deer density in open areas was 5.77 ± 1.36 individuals/km2 in the Cerrado landscape, 5.45 ± 1.16 individuals/km2 in the seasonally flooded grassland landscape, and 5.97 ± 1.12 individuals/km2 in the cultivated pastures landscape. The average aggregation was 4.86 ± 1.6 at the cultivated pasture landscape, 2.65 ± 1.30 at the seasonally flooded grassland landscape, and 2.36 ± 1.14 in the Cerrado landscape, with significant difference between the natural landscapes and the cultivated pasture landscape. The present study showed that even in habitats dominated by exotic grasses, small patches of native vegetation are capable of aggregating individuals, indicating a preference for native resources.