Termites may have a bigger role in the future environment

Photo: Amy Zahn with graduate student Mariana Nardi and postdoctoral fellow Paulo Negri from the University of Estadual de Campinas near termite mounds in a tropical savanna in Chapada dos Federos National Park, São Jorge, Alto Paraíso de Goiás, Goiás, Brazil.
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Credit: Photography by Rafael Oliveira

Most people think of termites as a wood-consuming nuisance in homes and businesses. But these termites account for less than 4 percent of all termite species worldwide.

Termites are critical in natural ecosystems—particularly in the tropics—because they help recycle dead wood from trees. Without such a rottenness, the world would be crammed with dead plants and animals.

New research suggests that these energetic wood-consuming insects could soon move toward the North and South poles as global temperatures rise due to climate change.

In a new international study led by University of Miami biology professor Amy Zane, researchers have learned that termites play a pivotal role when it comes to wood breaking, contributing to the carbon cycle on Earth. They also learned that termites are very sensitive to temperature and precipitation, so as temperatures rise, the insect’s role in decomposing wood is likely to expand beyond the tropics.

“As temperatures rise, the impact of termites on the planet can be enormous,” said Zahn, Aresty’s chair of tropical ecology in the Department of Biology in the College of Arts and Sciences.

For the study published in the journal SciencesZhan, along with more than 100 collaborators, studied sites around the world where bacteria, fungi (microbes) and termites consume dead wood. They also investigated how temperature and precipitation affect wood detection and decay using the same experiment set up at more than 130 sites in a variety of habitats across six continents. Their results suggest that areas with high termite activity should increase as the land becomes warmer and drier.

“Termites were most influential in places such as tropical savannas, monsoon forests, and subtropical deserts,” Zahn added. “These systems are often underestimated in terms of their contribution to the global carbon budget.”

Amy Austin, associate professor of ecology at the University of Buenos Aires and Zanne’s collaborator, said the global study helped scientists gain broader insight into wood decomposition.

“The inclusion of hot and arid biomes, particularly in the Southern Hemisphere, where termites are frequent and active, allowed new insight into their role in carbon circulation,” Austin said. “As ecologists, we may need to broaden our view of woody ecosystems beyond the closed canopy forest and realize that woody carbon stores in drier ecosystems are an important component of the global carbon cycle.”

Although both microbes and termites decompose dead wood, there are important differences between them. While microbes need water to grow and consume wood, termites can operate at relatively low humidity levels. In fact, termites can search for their next meal even if it is dry and carry whatever they want to their piles, or even move their colony to the wood they eat.

“Microbes are globally important when it comes to wood rot, but we have largely overlooked the role of termites in this process. This means that we do not take into account the huge impact that these insects can have on the future carbon cycle and interactions with climate change.”

Like young cows, termites release carbon from wood as methane and carbon dioxide, two of the most important greenhouse gases. Therefore, Zan said, termites may increasingly contribute to greenhouse gas emissions as climate changes.

“I am intrigued by how the decomposition of microbial wood and termites affects how carbon is released back into the environment,” added Zahn, who has been studying reactions from carbon release from wood for more than a decade.

Zanne began her research on termites in 2008, and networked with other wood decomposition experts as she attended a working group in Sydney, Australia. This led to a major research project funded by the National Science Foundation and the Natural Environment Research Council in Queensland, Australia, which also involved collaborating with artist Donna Davis to photograph termites, microbes and decaying wood.

She expanded the study globally through social media and word of mouth, including researchers across career stages and sites with everyone doing the same experiment using locally sourced materials.

André M. D’Angioli, a Brazilian biologist, collaborated on the project as part of his doctoral thesis at Universidade Estadual de Campinas.

“Participation in the Global Timber Project was a major step in my research,” he said. “It was fascinating to see how the regional data I collected in Brazil correlated with the global patterns found in this paper.”

Zahn said the opportunity to lead a research endeavor on a global scale has been very rewarding.

“This is one of the most amazing projects I’ve worked on,” Zahn said. “It was a truly international collaboration. Our ability to better understand wood decay and parts of the carbon cycle on a global scale is now even stronger thanks to this research.”

The study, “Temperature Sensitivity of Termites, Affects Global Wood Decay Rates,” was published in the September 23 issue Sciences him too Available online.

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