Site occupancy models to assess the impact of human activities and identify important areas for biodiversity

Background/Question/Methods

As human activities continue to degrade natural habitats for wildlife, there is a need to document species distributions, population changes, and to identify priority areas for conservation in order to make informed and effective management decisions. In this presentation we discuss the application of site occupancy models to derive inference regarding the impact of human activities on biological communities using data from a 2-year breeding bird survey of disturbed and undisturbed forest patches in the Sierra Tarahumara region of Mexico. We demonstrate how vital population rates derived from occupancy models can be used to quantify and model the ecological effects of timber harvesting interventions in terms of species’ occupancy and persistence probabilities.

Results/Conclusions

Based on our analyses we found that there is a positive relationship between occupancy and persistence probabilies of bird species with the diversity of species and structural features of forest patches. The observed pattern supports the hypothesis that the disturbance caused by recent timber extraction reduces species diversity and probability of occupancy. We also note that although we expected to find higher occupancy uncertainty in sites with less degraded forest structures, we found higher uncertainty in more homogeneous (structurally simpler) forest patches. In this particular situation, additional sampling is required in more degraded habitats to reduce estimate uncertainty. We present an analytical approach that can be used by managers to increase site-level avian occupancy and species diversity, and identify important biodiversity conservation areas based on habitat characteristics alone.