The University of Pretoria (UP) recently participated in an international study led by the University of Miami to investigate termite and microbial wood discovery and decay.
“From a southern African perspective, this study shows how important termites are in the decay of wood, particularly in dry savannahs,” says Professor Mark Robertson of UP’s Department of Zoology and Entomology.
Most people think of termites as the little wood-devouring white ants which eat away at patios and wendy houses but those termite species are only 4% of all termite species on earth.
Termites are critical in natural ecosystems, especially in the tropics, because they help recycle dead wood from trees.
UP said in a press release that “without such “decayers”, the environment would be piled high with dead plants and animals.” But new research indicates that these energetic, wood-consuming insects could soon be moving towards the North and South poles as global temperatures rise as a result of climate change.
Professor Catherine Parr and PhD student Katherine Bunney were instrumental in UP’s contribution to the global study, particularly from the perspective of termite activity and biodiversity in the southern hemisphere.
Researchers from UP conducted field experiments in a wet savannah near Hoedspruit and further north in much more arid savannah in the Nwanedi Nature Reserve, using wood blocks in decomposition bags.
“Upon returning to collect our wood decomposition bags after just six months, I was intrigued to discover that the contents of every ‘open’ bag which allowed access to termites, were almost entirely consumed,” Bunney said.
“The wood blocks were hollowed out, leaving just a thin shell of wood, and were filled with termite sheeting soil and dead termites. In contrast, the closed bags were just as they had been left six months prior. The Nwanedi Nature Reserve is incredibly dry; it’s hot with a lot of bare ground. In summer, it was too hot to do much fieldwork after 9am. This is a seemingly inhospitable place, yet termite activity is so high,” she said.
Through this study, which was led by University of Miami Professor Amy Zanne, researchers learned that termites are pivotal when it comes to breaking down wood, contributing to the earth’s carbon cycle.
They also discovered that termites are significantly sensitive to temperature and rainfall; this means that as temperatures rise, the insect’s role in wood decay will likely expand beyond the tropics.
“With temperatures warming, the impact of termites on the planet could be huge,” says Zanne, the Aresty chair of Tropical Ecology in the College of Arts and Sciences’ Department of Biology.
For the study, Zanne, along with more than 100 collaborators, studied locations across the globe where bacteria and fungi (microbes) and termites consume dead wood.
They investigated how temperature and rainfall affected the discovery and decay of wood by using the same experimental 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 earth becomes warmer and drier. “Termites had their biggest effects in places like tropical savannahs, seasonal forests and subtropical deserts,” Zanne explains.
“Being involved in the global wood project was a major step for my research.
“It was fascinating to see how the regional-scale data I collected in Brazil was related to the global patterns found in this paper,” she says.
Zanne says the chance to spearhead a global-scale research endeavour was extremely rewarding.
“This is one of the most incredible projects I’ve worked on. It was truly international collaboration.
“Our ability to better understand wood decay and parts of the carbon cycle on a global scale is now stronger because of this research,” she says.
The study, “Termites sensitivity to temperature effects global wood decay rates”, was published in the journal Science and is also available online.