Cascading effects of termite mounds in African savannas

ABSTRACT African termites are classified into five distinct families, Termitidae, Rhinotermitidae, Hodotermitidae, Termopsidae and Kalotermitidae. Termites are undoubtedly one of the key ecosystem engineers. Because they harbour more nutritive plants, herbivory by large herbivores is biased towards mounds. Their engineering role is visible through construction of conspicuous termite mounds, which often harbour some unique species compared with the expansive ecosystem in which they occur. To understand the cascading effects of termite mounds on ecosystem functioning, we present a review on how termites create ecosystem heterogeneity, and how this heterogeneity in terms of soil physical and chemical characteristics, particularly nutrients, further influences vegetation production, diversity and palatability to large herbivores. Here we review literature mainly focusing on: (i) Phylogeny (evolutionary history) of African termites, (ii) mound construction, (iii) mound spatial distribution, (iv) termite foraging (v) termite nutrient cycling, (vi) termite influence on hydrology, (vii) termite mound influence on plant species diversity and (viii) termite mound influence on large herbivores. Our review showed that African termites are diverse, with the potential to influence ecosystems heterogeneity through soil nutrients enrichment, which in turn influences forage abundance (thicket clumps), diversity and quality. High forage quality occurring on termite mounds influences herbivory patterns in the savanna ecosystem. Herbivory is reported to be higher on termite mounds compared to the expansive savanna landscape. The most common plant family occurring on termite mounds is Capparaceae. We suggest that future studies focus more on: (1) the influence of termite mounds on plant functional traits, (2) the importance of termite mounds in dryland savanna cropping/rangeland systems, and (3) on ways to support establishment of mound building termite species.