Season and Vegetation Cover Effects on Dung Beetle Assemblages in East African Savanna Habitats

Abstract

Seasonality and vegetation cover play a crucial role in shaping the composition of dung beetle communities worldwide. This study examines the influence of dry and wet seasons across four distinct vegetation types: marshland, closed miombo woodland, open miombo woodland, and riverine vegetation in Nyerere National Park. Buffalo dung (40g) served as bait, and canopy cover was assessed using a spherical densiometer, and ground cover, along with the extent of bare ground, was estimated with a 0.5m² quadrat. A total of 5,534 dung beetles were trapped, encompassing nine tribes, 29 genera, and 63 species. Notably, species richness and diversity were significantly greater during the wet season than in the dry season. The predominant species identified in the dry season included Catharsius tricornutus, Euoniticellus intermedius, and Liatongus militaris, while the wet season was dominated by Digitonthophagus gazella, Gymnopleurus, and Garreta nitens. This study underscores the importance of maintaining optimal conditions of canopy cover (>30%) and ground cover (>30%), along with reduced bare ground, to enhance abundance and species richness within dung beetle assemblages across seasons. Conservation initiatives should prioritise preserving habitat heterogeneity with diverse vegetation cover, particularly a combination of closed and open miombo woodlands, which are vital for sustaining diverse dung beetle communities.