With biomass densities comparable to large ungulates and megaherbivores, termites play a key functional role in many tropical savanna ecosystems. This study focuses on vegetated termite mounds (termitaria) constructed by the Termitidae species Macrotermes herus. We studied how resource rich termitaria affect graminoid herbs (Poaceae and Cyperaceae), forbs and woody species composition and diversity. The density of termitaria explained 89% of the variation in dense thickets in the area. Fire tolerant Acacia species dominated the open savanna while fire sensitive species like Grewia spp. and the succulent Euphorbia candelabrum were restricted to termite mounds. Termitaria plots had four times the mean number of woody species and supported three times as many forb species as the adjacent savanna. For woody species, both the Shannon-Wiener index and the Shannon evenness index were higher on temitaria than on the savanna. There were no differences for graminoid herbs, except for the Shannon evenness index which was higher on termitaria. Our results indicate that graminoid herb richness peaks at lower productivity levels than trees and forbs in savanna ecosystems, as also recently found in temperate areas.

In constructing large vegetated mounds, Macrotermes termites play a key functional role in many African savanna systems. This study focuses on ungulate feeding on Macrotermes termitaria vegetation in Lake Mburo National Park, Uganda. With the exception of oribi Ourebia ourebi, all the species studied (i.e. impala Aepyceros melampus, Burchell's zebra Equus burchelli, Defassa waterbuck Kobus ellipsiprymnus, topi Damaliscus lunatus, bushbuck Tragelaphus scriptus and warthog Phacochoerus africanus) grazed preferentially on mound areas compared to the adjacent savanna. Ruminant species grazed closer to termitaria than non-ruminants and female impala both browsed and grazed closer to mounds than males. No sexual difference in grazing distance to mounds was found for waterbuck.