A Princeton University research team has found that termites can actually slow the desertification process by creating small oases of plant life. Their results suggest that not only prevent the spread of deserts into semi-arid ecosystems and agricultural lands but can also increase their resilience to climate change.
In the arid savannas and grasslands termite mounds are sometimes the only bastions of moisture and nutrients. Additionally, termites create internal tunnels which allow water and nutrients to more easily penetrate soils. This results in lush vegetation growing near and around termite mounds in ecosystems at high risk of desertification. The Princeton University study was recently published in the journal Science states that termites can slow the spread of deserts by providing a moist refuge for vegetation in and around their mounds. Arid ecosystems are able to survive with significantly less rainfall when they have inhabiting termite mounds. While this research was based on termites of the genus Odontotermes who grow fungus, the results apply to all termites whose mounds increase resource availability.
Termite mounds also act as a seed bank and plant reserve which helps dry ecosystems rebound quickly when rainfall resumes. Corina Tarnita, co-author this study and Princeton assistant professor in ecology and evolutionary biology explains; “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.” Vegetation around mounds persists longer and declines slower, even when harsh conditions cause vegetative dieback, revegetation is much quicker. Termite give these severe ecosystems a much better shot at recovery from extreme weather conditions.
Grasslands and savannas have 5 transitional stages before becoming deserts, each one has an associated, distinctive plant growth pattern. These growth patterns are monitored via satellite by scientists to determine risk and make predictions on timeline. The Princeton researchers found that plant growth patterns exist on a far smaller scale than previously thought, and a pattern of termite mounds covered in dense vegetation overlays them. Termite mound patterns appear very similar to the final stage in the transition from drylands to desert. Historical data suggests two different mechanisms can be responsible 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, these mechanisms are not mutually exclusive. This inspired the Princeton research team to look into more than one driving mechanism being responsible for vegetation dynamics in dryland ecosystems. Tarnita said. “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.”
Thus, Tarnita and her co-authors showed that vegetation patterns currently interpreted as the onset of desertification could mean the total opposite — that plants are persevering thanks to termite mounds.