Habitat Heterogeneity Shapes Bee Species Diversity and Community Structure in an East African Protected Ecosystem

Abstract

Bees are crucial in maintaining ecosystem functioning, yet their populations are declining due to human-induced threats that impact pollination services, which are essential for ecosystem viability. Understanding how different habitats shape bee community structure and diversity is crucial for effective insect conservation. In this study, we assessed the bee species composition, richness, and abundance across grassland, open woodland, and closed woodland habitats within a protected miombo woodland ecosystem, an important Zambezian regional center of endemism. Bee species diversity was comparable across habitats, with grasslands showing slightly higher diversity than woodlands. Statistical analysis revealed no significant differences in diversity among habitats; however, indicator species analysis revealed distinct species distributions. For example, Apis mellifera, Macronomia fulvohirta, Megachile spp., and Xylocopa flavorufa showed habitat-specific abundance patterns, reflecting niche preferences. Beta diversity results from Principal Coordinate Analysis (PCoA) indicated overlapping bee community structures across habitats, with a similarity index of 37%. Grasslands exhibited higher diversity, which may be linked to structural openness, diverse floral resources, and lower predation, enhancing bee foraging. Open woodlands, despite low species richness, had high bee abundance, likely due to adaptable generalists like Apis mellifera. Closed woodlands, while supporting fewer individuals, hosted high species richness, suggesting their role in sustaining diverse bee communities. Our findings emphasise the importance of habitat connectivity and heterogeneity. Conservation managers should prioritise protecting diverse habitats to protect bee populations, ensuring the persistence of key pollination services and overall ecosystem resilience amid ongoing land-use changes.