Gretchen North

Soil macrofauna are useful indicators of soil health given their low resistance to environmental stressors. Anthropogenic land use change impacts contribute to the magnitude of these stressors on soil macrofauna communities. Despite their importance, soil macrofauna remain understudied in the Eastern Afrotropics. The greater Serengeti-Mara ecosystem (GMSE) holds high conservation value and is experiencing human-induced environmental strain. Our study surveyed soil macrofauna communities across four habitat types: bush/forest, grassland, human use, and wetland following Anderson & Ingram’s 1994 protocol. We focus here on the community structure and dynamics of ants (Hymenoptera: Formicidae), termites (Insecta: Isoptera), and earthworms (Annelida: Oligochaeta) due to their relative abundance and role as ecosystem service provisioners. Observed abundance and presence patterns varied between our three taxa of interest. Ants had highest abundances throughout the entire study system, with highest habitat-specific abundances in grassland and human use areas. Earthworms were found most frequently and in higher numbers within bush/forest and wetland habitat types. Termite abundances were low system-wide apart from one site, emphasizing the degree to which landscape-scale spatial heterogeneity plays a role in the spatial patterning of soil macrofauna communities. A redundancy analysis (RDA) biplot and replotted Euclidean values revealed partitioning of habitat types along a gradient of moisture availability. Given the semi-arid climate of the area within which we sampled, it is reasonable that moisture availability is a driving factor in the spatial patterning of soil macrofauna communities. Ants communities remained relatively robust in resource-limited patches, indicating a potential avenue for focusing soil macrofauna monitoring and conservation efforts. This study addresses the importance of baseline ecological monitoring for sustainable land management from the ground up.