According to Princeton University researchers, the spread of these deserts is increasing. Nothing has been able to stop them from expanding except perhaps termites. The termite mounds protect the South American dry grasslands from climate change. They are able to store nutrients and moisture, as well as allowing water to seep into the soil through their network of tunnels. The scientists think that termite mounds in drylands can encourage vegetation to grow around them. This could help stop desertification. In Science, the researchers wrote that drylands could survive without much rainfall if they had termite mounds. The study was focused on Odontotermes termites, which are fungus-growing termites. The findings could be applied to other types of termites, they believe. The termite mounds could help drylands resist climate change. Corina Tarnita (Image from Science), Princeton University assistant professor of ecology and evolutionary biology, stated that termite mounds can help protect plant life and seeds and help them recover as soon as the rains start to fall. Professor Tarnita stated that although the rain falls everywhere, termites let water penetrate soil more effectively, so plants can grow near or on the mounds like if it were raining. It is easier to replant vegetation around termite mounds than in harsher conditions. The ecosystem will recover if the mounds remain. Jef Huisman (University of Amsterdam) is a professor of aquatic microbiology and theoretical ecoologist. He said that the Princeton research suggests that the recently proposed early-warning signs for desert expansion may not be as complex as it seems. Future climate change predictions that ignore complexity of the natural world could also result from the simple prediction. Each stage of grasslands and savannas before becoming deserts is different, each with its own pattern for plant growth. Satellite images are used by scientists to identify the five stages of savanna growth. The researchers discovered that the plant-growth patterns are occurring on a smaller scale than originally thought, at a mere centimeter. The termite mounds are covered with dense vegetation. This can be seen overlaying the two. Professor Tarnita said that the termite mounds look very similar to the fifth stage, which marks the transition from grasslands to desert. This research was inspired in part by Odontotermes, a genus of fungus-growing termites. Image: Princeton University. The researchers described two mechanisms that could explain a similar pattern. The other stems from the self-organization of vegetation in response to low rainfall. 2. One was a result of termite mounds that were bustling and enhancing the quality of life for nearby plants. These mechanisms aren’t necessarily mutually exclusive, though, in drylands. Professor Tarnita stated that “that made me wonder whether more than one mechanism controls vegetation dynamics in dryland ecosystems.” A mathematical model was created that showed these mechanisms could co-exist but probably at different scales. “It led me to wonder if more than one mechanism is responsible for vegetation dynamics in dryland ecosystems. Prof. Huisman said that the Princeton team found that vegetative patterns which may seem to be heading towards complete desertification might not actually be that way thanks to termite mounds. Professor Huisman stated that ecosystems are more resilient and less likely to be destroyed if there is coexistence at different scales. This was the importance of the study. We need to adapt our climate models to drylands, as these ecosystems are more resilient to desertification than previously thought. Robert Pringle (a Princeton assistant professor of ecology and evolutionary biology), was a co-author. He said that their research on termite mounds found in drylands could also be applicable to other mound-building animals such as gophers and prairie dogs. Professor Pringle stated that “this phenomenon and these patterned landscaping features are common. Although termites are not the only ones causing these phenomena, they can have very similar impacts on ecosystems. It is difficult to predict what each animal will do to vegetation. This study is based on a paper published in 2010 PLOS Biology. Prof. Pringle is the lead author. The study found that termite mounds are “hotspots,” which increase plant growth and decrease animal activity. The termite mounds are also evenly spaced, creating more biological diversity. Professor Pringle stated that termites are a linchpin of an ecosystem. For this study, Professor Juan Bonachela from Strathclyde University, Scotland explained how a mathematical model was created to examine the effects of termite mounds on plant growth. This allowed Prof. Bonachela to use large-scale observations to better understand the effects of termites on vegetation. Professor Bonachela stated that similar studies in field would prove difficult and require long-term research. These models allow us to explore the focal system without any constraints of space or time and to examine a broad range of environmental conditions with an unprecedented level of detail, which is not possible in the field. Science 6 February 2015: 347 (6222), 651-655. [DOI:10.1126/science.1261487]
