When we consider termites, we can think of the danger they can pose to our homes once they take up residence and start eating wood. But, in fact, only about 4% of termite species around the world they are considered pests that could, at some point, eat your home.
In nature, wood-feeding termites play a large and important role in warm tropical and subtropical ecosystems. By feeding on wood, they recycle essential nutrients to the soil and release carbon into the atmosphere.
Our new research published today in Sciences, quantified for the first time how much termites love heat. The results are surprising: we found that termites eat dead wood much faster in warmer conditions. For example, termites in a region with temperatures of 30℃ will eat wood seven times faster than in a place with temperatures of 20℃.
Our results also point to an increasing role for termites in the coming decades, as climate change increases their potential habitat across the planet. And this, in turn, could cause more carbon stored in dead wood to be released into the atmosphere.
Dead wood in the global carbon cycle
trees They play a fundamental role in the global carbon cycle. They absorb carbon dioxide from the atmosphere through photosynthesis, and approximately helped of this carbon is incorporated into the new plant mass.
while most trees they grow slowly in height and diameter each year, a small proportion die. His remains then enter the pool of dead wood.
Here carbon accumulates, until the dead wood is burned or rotten through the consumption of microbes (fungi and bacteria), or insects such as termites.
If the stock of dead wood is rapidly consumed, the carbon stored there will be rapidly released into the atmosphere. But if decomposition is slow, then the size of the dead wood accumulation can increase, slowing the buildup of carbon dioxide and methane in the atmosphere.
For this reason, understanding the dynamics of the community of organisms that break down dead wood is vital, as it can help scientists predict the impacts of climate change on the carbon stored in terrestrial ecosystems.
This is important as the release of carbon from dead wood into the atmosphere could accelerate the rate of climate change. Storing it longer could slow climate change.
Testing how fast termites eat dead wood
Scientists generally understand the conditions that favor the consumption of dead wood by microbes. We know your activity typically double with every 10℃ temperature rise. The microbial decomposition of dead wood is also usually more rapid in humid conditions.
On the other hand, scientists knew relatively little about the global distribution of deadwood-eating termites, or how this distribution would respond to different temperatures and humidity levels in different parts of the world.
To better understand this, we first developed a protocol to assess dead wood consumption rates by termites and tested it in a savanna-rainforest ecosystem. in North East Queensland.
Our method was to place a series of mesh-covered wooden blocks on the ground surface in places. Half of the blocks had small holes in the mesh, giving termites access. The other half had no such holes, so only microbes could access the blocks through the mesh.
We collected wooden blocks every six months and found that mesh-covered blocks with holes decomposed faster than those without holes, meaning that the contribution of termites to this decomposition was, in fact, significant.
But while the test told us about termites in Queensland, it didn’t tell us what they might be doing elsewhere. Our next step was to reach out to colleagues who could implement the woodblock protocol at their study sites around the world, and they enthusiastically accepted the invitation.
In the end, more than 100 collaborators joined the effort at more than 130 sites in a variety of habitats, spread across six continents. This broad coverage allowed us to assess how termite wood consumption rates varied with climatic factors, such as mean annual temperature and precipitation.
Termites love warmth and not too much rain.
For woodblocks accessible only to microbes, we confirmed what scientists already knew: that decay rates roughly doubled across sites for every 10℃ rise in mean annual temperature. Decomposition rates increased even more when sites had higher annual rainfall, such as in the tropical rainforests of Queensland.
For termite woodblocks, we observed a much more pronounced relationship between decay rates and temperature: dead wood generally decomposed almost seven times faster in sites that were 10℃ warmer than others.
To put this into context, termite activity meant that blocks of wood near tropical Darwin in the far north of Australia decomposed more than ten times faster than those in temperate Tasmania.
Our analyzes also showed that termite consumption of wood blocks was higher in warm areas with low to intermediate mean annual rainfall. For example, termite decomposition was five times faster in a subtropical desert in South Africa than in a tropical rainforest in Puerto Rico.
This could be because termites are safe in their mounds and can access water deep in the soil in dry times, while waterlogging can limit their ability to search for dead wood.
Termites and climate change
Our results were synthesized into a model to predict how termite consumption of dead wood might change globally in response to climate change.
Over the next few decades, we predict increased termite activity, as climate change projections show that suitable habitat for termites will expand north and south of the equator.
This will mean that carbon cycles through the dead wood pool faster, returning carbon dioxide fixed by trees to the atmosphere, potentially limiting carbon storage in these ecosystems. Reducing the amount of carbon stored on land could start a feedback loop to speed up the pace of climate change.
We have long known that human-caused climate change would favor a few winners but leave many losers. It seems likely that the humble termite is one of those winners, poised to experience significant global expansion in its primary habitat.
Termites may have a larger role in future ecosystems
quotes: Termites Love Global Warming, Rate of Their Wood Chewing Gets Significantly Faster in Warmer Climates (2022, Sep 24) Retrieved Sep 24, 2022 from
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