The regular polka-dot pattern of termite mounds on the savannah of central Kenya supports a great abundance of plant and animal life – more than the region could support without the termites. The discovery, made by American and Belgian scientists, suggests regular patterns like this are so beneficial we should expect to see them in many other ecosystems.
The red dots are termite mounds. Image: Robert M. Pringle/Plos Biology
While studying geckos on the African savannah, the scientists noticed that the lizards tended to congregate around the sprawling termite mounds. Looking more closely, they discovered that it wasn’t just lizards that preferred the mounds – they were covered in a dense layer of plants and animals. The numbers of plants and animals decreased as the scientists moved further away from the mound, suggesting the mounds were responsible for supporting a thriving local ecosystem, but how do they do so?
The scientists aren’t sure. They think the termites, which create elaborate nests up to ten metres across, alter the soil structure by mixing in larger particles of soil. This helps water filter down to plant roots. The termites also seem to stir into the soil more nutrients such as phosphates and nitrogen, which plants need to grow. Increasing the number of plants boosts herbivore and insect numbers, which draws in predators like the geckos.
It doesn’t stop there. The regular spacing of the termite mounds across vast swathes of savannah support a much more productive ecosystem on a much larger scale. The regular spacing means no area is very far from a mound and its life-supporting effects, so the entire ecosystem can be more productive.
The findings should also be useful in completely different environments: conservation work to restore coral reefs or forests can use the idea of regular ‘polka-dot’ spacing to ensure that the fragile ecosystems are as strong as possible while they recover.
Paper Reference: Pringle RM, Doak DF, Brody AK, Jocqué R, Palmer TM, (2010) Spatial Pattern Enhances Ecosystem Functioning in an African Savanna. PLoS Biology, 8(5). e1000377. doi:10.1371/journal.pbio.100037
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