Relações ecológicas na distribuição de 25 espécies de vertebrados neotropicais em mesoescala

Abstract

Vertebrates are a vital component of Amazon forest biodiversity. Although vertebrates are a functionally important part of various ecosystem services (supporting, provision and cultural) they continue to be threatened by anthropogenic perturbations including hunting and habitat loss across the Amazon. Here we use a standardized regularly spaced arrangement within 25km2 to provide a baseline assessment of vertebrate species diversity in a sustainable use protected area in the eastern Brazilian Amazon. Camera traps were placed for 30 days during both dry and wet seasons at 30 points separated by 1km intervals along a pre-established trail system. Mann-Whitney U tests were used to examine seasonal differences in the per species encounters (number of photos per camera trap and number of cameras with photos). Generalized linear models (GLMs) were then used to examine the influence of five variables (altitude, canopy cover, basal area, distance to nearest river and distance to nearest large river) on the number of photos per species and in functional groups. GLMs were also used to examine the relationships between large predators [Jaguar (Panthera onca) and Puma (Puma concolor)] and their prey. A total of 649 independent photos of 25 species were obtained from 1800 camera trap days (900 each during wet and dry seasons). Only ungulates and rodents showed significant seasonal differences in the number of photos per camera. The number of photos differed between seasons in only three species (Mazama americana, Dasyprocta leporina and Myoprocta acouchy) all of which were photographed more (3 to 10 fold increase) during the wet season. M. americana was the only species where a significant difference was found in occupancy with more photos in more cameras during the wet season. For most groups and species our GLMs only weakly explained variation in the number of photos per camera (deviance explained ranging from 10.3 to 54.4%). Terrestrial birds (Crax alector, Psophia crepitans and Tinamus major) and rodents (Cuniculus paca, Dasyprocta leporina and M. acouchy) were the notable exceptions with our GLMs significantly explaining variation in the distribution of all species (deviance explained ranging from 21.0 to 54.5%). The group and species GLMs showed some novel ecological information from this relatively ―pristine area‖. In the case of groups we found no association between large cats and their potential prey. We also found that rodent and bird species were more often recorded closer to streams. As hunters gain access via rivers this finding suggests that there is currently little anthropogenic impact on the species. Our findings provide a standardized baseline for comparison with other sites and with which planned management and extractive activities can be evaluated.