Desertification is a growing problem in many parts of the world, mostly owing to common human activities such as agriculture, animal husbandry (grazing), and groundwater use. It’s a common topic of discussion in some fields of scientific research (and elsewhere) how best to address this issue.
And now, new research from Princeton University is suggesting that the answer (or at least a partial answer) has been right in front of our faces the whole time, and is a bit obvious — termites.
While many people seem to have something of a visceral dislike of the insects (despite people in many parts of the world enjoying them as food), the new research has found that they could be integral to the arrest of the process of desertification in many parts of the world. In particular, into agricultural lands and semi-arid ecosystems.
The research found that termite mounds could go a long ways toward making these areas more resilient to the process of desertification, and to the broad climatic changes anticipated in the coming decades as a result of industrial activity.
Termite mounds are something like oases in the parched drylands of much of the equatorial world — working to modulate the immediate environment via the nutrients and moisture stored in the extensive internal tunnels (which allow water to better penetrate the soil). Owing to this, termite mounds are often surrounded by abundant vegetation — and can work to counteract the wider environment’s desertification.
The new research from Princeton University — published in the journal Science — found that “drylands with termite mounds can survive on significantly less rain than those without termite mounds.”
Other mechanisms apply as well, though — the preservation of seeds for example, which allows a faster rebound and growth once rainfall increases.
Study author Corina Tarnita stated: “The rain is the same everywhere, but because termites allow water to penetrate the soil better, the plants grow on or near the mounds as if there were more rain. The vegetation on and around termite mounds persists longer and declines slower. Even when you get to such harsh conditions where vegetation disappears from the mounds, re-vegetation is still easier. As long as the mounds are there the ecosystem has a better chance to recover.”
A recent press release from Princeton University provides more:
Recently proposed early-warning signals for the desertification of arid ecosystems can be too simple, and possibly result in projections of future climate change that do not account for the complexity of nature. For grasslands and savannas, for instance, five stages mark the transition to desert, each having a distinct pattern of plant growth. Scientists use satellite images to determine which stage a savanna is in and which stage it is heading toward.
The Princeton researchers, however, found that these plant-growth patterns exist on a much smaller scale than previously thought, one of centimeters. Overlaying them is the pattern of termite mounds covered by dense vegetation, which is on the scale of tens of meters.
The termite-mound pattern, however, looks deceptively similar to the last and most critical of the five stages that mark the transition of drylands to desert, Tarnita said. The scientific literature contains two different mechanisms for a similar pattern — one stems from vegetation self-organizing in response to limited rainfall, and the other results from bustling termite mounds improving the lives of nearby plants. But these mechanisms are not necessarily mutually exclusive in drylands, Tarnita said.
“That made me wonder if more than one mechanism is responsible for vegetation dynamics in dryland ecosystems, as is often the case in nature,” Tarnita explained. “We created a mathematical model that revealed that these mechanisms can co-exist, but likely at different scales. It pointed to where we should look in nature to find the nested patterns that eventually led us to empirically confirm that both mechanisms are indeed at play.”
“The coexistence of multiple patterns at these scales makes ecosystems more robust and less prone to collapse, and that is the significance of this study,” she added. “In that sense, we have to adjust our models for drylands because these ecosystems are much more resistant to desertification than we previously believed.”
These findings can also be used, of course, as a means of protecting against desertification caused or exacerbated by human activities such as farming and animal husbandry in dryland regions.
Co-author on the study, Robert Pringle, also notes that, given the findings, it seems likely that other environmental engineers, such as ants, gophers, prairie dogs, etc, could be responsible for similar effects.
“This phenomenon and these patterned landscape features are common. It’s not always termites causing them, but they may very well have similar effects on the ecosystem,” Pringle stated. “However, exactly what each type of animal does to the vegetation is hard to know in advance. You’d have to get into a system and determine what is building the mounds and what are the properties of the mounds. I like to think of termites as linchpins of the ecosystem in more than one way. They increase the productivity of the system, but they also make it more stable, more resilient.”
Image Credits: Robert Pringle, Princeton University Department of Ecology and Evolutionary Biology