Empirical Analysis of Forest Fragmentation Effects on Dung Beetle Diversity and Ecosystem Function in Edo State, South South Nigeria

Dung beetles perform vital ecosystem functions including nutrient cycling, seed burial, and parasite regulation, and are sensitive indicators of habitat quality and fragmentation. This study empirically analysed how forest fragmentation affects dung beetle species diversity, community composition, and associated ecosystem functions in Edo State. Dung beetle communities were sampled using baited pitfall traps at twenty-four sites in forest fragments of three size classes, continuous forest reference sites, and forest matrix habitats. Fragment size, isolation distance, and matrix permeability were quantified using landscape metrics derived from satellite imagery. Dung burial rates and soil turning rates were measured as functional proxies. Multilevel statistical models were used to partition variance in beetle diversity attributable to fragment size, isolation, and matrix type. Results showed significant positive relationships between fragment area and both species richness and functional diversity. Small fragments below 50 hectares had severely impoverished communities dominated by generalist edge-tolerant species. Dung burial rates were 67 percent lower in small fragments than continuous forest, indicating functional impairment. Matrix quality moderated fragmentation effects, with beetle diversity higher in fragments connected by secondary woodland compared to those isolated by bare cropland. These findings provide the first empirical data on fragmentation effects on dung beetle function in South South Nigeria and support minimum fragment size thresholds in conservation planning guidelines. Keywords: dung beetles, forest fragmentation, ecosystem function, Edo State, landscape ecology.