Miombo woodland termite mounds: resource islands for small vertebrates?

Abstract

Macrotermes mounds are a significant feature of African woodland landscape, contributing to habitat heterogeneity. The mounds are massive, often many centuries old, and support dense vegetation and a suite of woody plant species scarce in surrounding woodland. The present study tested the hypothesis that Zimbabwean Macrotermes mounds, with their greater niche availability, were more heavily utilized by small vertebrates than the surrounding miombo woodland. We carried out a survey of amphibian, reptile and mammal species during early and late rains for 16 termite mounds and 16 adjacent woodland habitat sites, and compared numbers of individuals, species and diversity. For amphibians and reptiles, individual numbers and species did not differ significantly between habitats and their activity was more influenced by season. For mammals, however, significantly more individuals and species were captured on termite mounds, with three species captured only on mounds (most notably the musk shrew Crocidura hirta spp. complex) and all others showing marked preference for this habitat. The greater number of mammals on termite mounds contributed to total small vertebrate biomass being 800 g/ha for termite mounds compared with 380 g/ha in woodland. For mammals certainly, Macrotermes mounds provide significant food and habitat in miombo woodland.