Habitat type and altitude work in tandem to drive the community structure of dung beetles in Afromontane forest

Abstract: Dung beetles are a species group highly recognized for their sensitivity to anthropogenically induced change. There are few studies of the dung beetle communities found in Afromontane forests despite these forests forming part of a global hotspot of biodiversity. We used comparisons of diversity to investigate the effect of habitat and altitude on the species composition of Scarabaeidae dung beetles in six Afromontane habitat types and identified indicator species associated with each forest type. A total of 8020 individuals from 34 species belonging to 16 genera were captured at twelve transect locations across a 1.5 km altitudinal gradient. All indices measuring diversity and dominance showed significant differences between forest types with little overlap in the species composition detected in each. Altitude was negatively correlated with dung beetle abundance, species richness, and diversity, and there were also significant differences in abundance, species richness and diversity between altitude zones. Eight indicator species were identified for potential use in future conservation management or monitoring programs. This study found no significant relationship between species richness and forest type but an interaction between the two factors. Altitude in conjunction with forest type are the main factors in shaping dung beetle species composition in this Afromontane forest. Our results suggest the most important characteristic for determining community structure was mean canopy cover per forest type. Results from a previous short study conducted in 1974 indicate while there was significant overlap between dung beetle species caught 40 years ago and the present day there were also seven species which were absent. All seven of these species have climatic distributions centered around the wet highlands of East Africa and further work is urgently required to understand why these species are no longer detectable in the ANP. Implications for insect conservation: Our results have important conservation implications as they underscore the importance of preserving forest heterogeneity to maintain maximum dung beetle diversity within mountain ecosystems. The identified differences in dung beetle diversity between forest types and the high turnover of dung beetle species between altitude zones should heighten the importance for instigating future Scarabaeidae conservation initiatives in Afromontane regions.