Diversity and distribution of termite genera along a catenal gradient in Southern Kruger National Park

Background/Question/Methods

Termites (Isoptera) play an important role as ecosystem engineers in savannas by altering and maintaining soil moisture and nutrient concentrations.  They use soil selectively to construct nests and mounds that vary in shape and size both within and between species. Mound building termites including Macrotermes generally build mounds on well-drained soils to avoid inundation. When constructing mounds, termites display preferences in soil particle selection to best match their ecological, physiological, and behavioral needs. We hypothesize that this will lead to spatial differences in both termite diversity and mound morphology associated with soil types in heterogeneous savanna environments.  While previous studies have described the broad-scale patterns of termite distribution in Southern Africa, the regional perspective, may overlook significant patterns of termite diversity and behavior at the landscape scale. In the Kruger National Park, South Africa, patterns in distribution and diversity may result from changes in soil characteristics along a catenal slope.  Our study seeks to investigate termite diversity and distribution.  We addressed the following questions in our research: 1) What is the diversity of termite genera within our study site? 2) How do termite mound morphologies vary within the study area?

Results/Conclusions

In a survey of termite distribution along a catena in the Southern Kruger Park, we observed 12 genera, including all five mound builders present in the park. All mounds surveyed were photographed, measured for height and circumference, and categorized into four types that illustrate the changes in mound morphology down the slope of the catena. Termite identification data of 161 samples collected from mounds and wood were used to create distribution maps. Three major patterns in genus distribution emerged: random distribution above and below the seepline, clumped distribution in relation to the seepline, and a higher richness downslope. We examined trophic preference and life history strategies related to mound homeostasis as possible explanations for these distribution patterns. Co-variation in termite taxonomic and functional groups with geomorphological characteristics illustrates the diverse role that termites play in savanna ecosystem functioning. The challenges in our study reflect the challenges to termite research as a whole, and also bring to light important future directions for soil macrofauna research.