Elephants, giraffes, lions and the wildebeests and gazelles they prey upon: the animals of Africa's savanna are legendary.
But they are not the true power brokers of the plains. None of these majestic animals would exist if it weren't for termites. According to a new study, an intricate pattern of regularly-spaced termite mounds underpin the entire savanna ecosystem. Without the mounds set up in just the right configuration, the whole system would likely cease to be.
It is an incredible example of emergent patterns giving rise to complexity in nature. On their own, termites seem like mindless toilers, building large mounds for the good of their colony.
Satellite images of their mounds reveal an that they are in fact far from random — the mounds together form a vast network, evenly spaced across the savanna (below — mounds are small dots at the center of the small red splotches, which
are area of high vegetation & productivity. Large red splotches are
abandoned cattle corrals).
The mounds can be 10 meters (33 feet) wide and take centuries to form. But a team of researchers, led by Robert Pringle of Harvard University think the termites replace fine silt and slay particles in the soil with coarser particles as they work. Coarse grains allow water to percolate, and keep the land from extreme expansion and contraction during times of drought.
In turn, this allows plants to colonize the area around the mounds (the red "starbursts" of productivity). In among the plants are a plethora of bugs; the bugs bring geckos and spiders; predators follow them on up the food chain. And the entire cascade of life depends on the diligent effort of these termites.
What's more, researchers found that when termite mound spacing was random, as opposed to evenly spaced 60-100 meters (197-328 feet) apart, the number of plants and animals the landscape could support fell off dramatically.
The team's study, published in the journal PLoS Biology, highlights just how wondrously interdependent ecosystems can be.
When we think about conservation, we tend to think mostly about the consequences of messing with large species we can see — lions, say, or polar bears or sharks. And that's true. But equally important is identifying the unseen architects of an ecosystem — the biological cement that binds the system together — and making sure that those subtle, natural patterns are not trifled with.
Image: PLoS Biology