Termites Lay Foundation for the Savanna Ecosystem

a cheetah sits atop a termite mound

Termites may hold the key to savanna ecosystem health. (Photo credit: Graeme Purdy/iStock/Getty Images)

The abundant grasses, iconic grazers, and legendary predators of the African savanna ecosystem all depend on one thing: fertile soil. Although it has long been known that termites play an important role in recycling nutrients in soil, researchers are now discovering that termites may do more than just contribute to the savanna ecosystem, they may make the whole thing possible.

Robert Pringle, an assistant professor of ecology and evolutionary biology, was studying lizards in the African savanna when he noticed that the lizards occur in surprisingly high numbers near termite mounds. He and his colleagues found that it isn’t just lizards that are higher in density near the mounds, but that plants, insects, and other animals aggregate there as well. They found that grasses grow taller on the mounds and trees bear more fruit there. In fact, ecosystem productivity and diversity, in general, spikes on top of each mound and then drops off considerably with distance away from the mound. Results of their research were published in the open access journal PLoS Biology. 

These bursts of ecosystem abundance, or hotspots, are especially striking when viewed from above. Satellite imagery shows uniformly distributed spots of rapid plant growth across the African savanna landscape. The spots are about 30 feet in diameter and are each spaced several hundred feet apart. Beneath each spot, millions of termites conduct their behind-the-scenes work of soil creation.

Typically viewed as pests, termites create fertile soil as they break down dead wood and plant materials and convert them to nitrogen and phosphorus, nutrients living plants need to grow. They also improve the soil by introducing coarser particles and enhancing water infiltration and retention.

According to Todd Palmer, an associate professor of biology at the University of Florida, and co-author of the study, the highly regular pattern of termite mound distribution is significant.

“In essence, the highly regular spatial pattern of fertile mounds generated by termites actually increases overall levels of ecosystem production. And it does so in such a profound way,” Todd Palmer said in a press release about the research. “Seen from above, the grid-work of termite mounds in the savanna is not just a pretty picture. The over-dispersion, or regular distribution of these termite mounds, plays an important role in elevating the services this ecosystem provides.”

According to data collected by Palmer’s lab, mound-building activity by termites significantly impacts soil characteristics. This in turn dramatically changes both the plant and animal communities (and how they interact) associated with the mounds. Apparently, this pattern creates a network that optimizes overall ecosystem productivity. Scientists are working to understand how these patterns emerge, how they enhance ecosystem productivity to such an extent, and what the ecological implications might be.

“Termites are typically viewed as pests, and as threats to agricultural and livestock production,” Pringle said in the press release. “But productivity–of both wild and human-dominated landscapes–may be more intricately tied to the pattern-generating organisms of the larger natural landscape than is commonly understood.”

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