COS 82-3 - Impacts of an indigenous settlement on taxonomic and functional dung beetle diversity in the Venezuelan Amazon

Wednesday, August 9, 2017: 8:40 AM
C125-126, Oregon Convention Center


Juanita Choo, Okinawa Institute of Science and Technology Graduate University; Evan P. Economo, Okinawa Institute of Science and Technology Graduate University


Traditionally nomadic indigenous communities in Amazonia have increasingly adopted more sedentary livelihoods in the last 50 years as a result of external influences. Permanent settlements lead to the concentration of disturbances (e.g., forest extraction and hunting) in nearby forest habitats, but their impacts on forest communities are not well understood. Here we evaluated the responses of taxonomic and functional alpha and beta diversity to human impacts near a permanent settlement of a traditionally nomadic indigenous population (the Hoti) in the Venezuelan Amazon. We studied responses of dung beetle diversity and community structure, as well as the responses of individual functional traits (activity period, food allocation strategies, and body size) to disturbance at different proximities to the settlement. We sampled dung beetles along four transects extending 4 km from the settlement and documented the corresponding number of plant species and canopy structure. Dung beetles were identified and assigned to their respective functional traits. We applied multiple regression on matrices to examine dung beetle diversity with respects to distance from the Hoti settlement, plant diversity, canopy structure. We used GLMM to examine beetle abundance response with respects distance to settlement, plant species, canopy structure, and beetle traits and two-way trait-distance/plant/canopy interactions.


Dung beetle species richness and alpha diversity increased significantly with distance from the settlement. While total beetle abundance was not influenced by distance from the Hoti settlement, the abundance of roller beetles increased with distance from the settlement and small-bodied beetles decreased in abundance with distance from settlement and canopy openness. We conclude that small-scale disturbances resulting from human settlements in Amazonia can result in significant impacts on the local biodiversity and functional response of dung beetle communities, but that there are significant differences from examining taxonomic and functional dimensions of diversity. This cascading effect of human activities can may ultimately influence ecosystem services that dung beetles provide including nutrient cycling and secondary seed dispersal services.