Thursday, April 3, 2014

Deforestation of sandy soils a greater threat to climate change

Yale News: Deforestation may have far greater consequences for climate change in some soils than in others, according to new research led by Yale University scientists — a finding that could provide critical insights into which ecosystems must be managed with extra care because they are vulnerable to biodiversity loss and which ecosystems are more resilient to widespread tree removal.

In a comprehensive analysis of soil collected from 11 distinct U.S. regions, from Hawaii to northern Alaska, researchers found that the extent to which deforestation disturbs underground microbial communities that regulate the loss of carbon into the atmosphere depends almost exclusively on the texture of the soil. The results were published in the journal Global Change Biology.

“We were astonished that biodiversity changes were so strongly affected by soil texture and that it was such an overriding factor,” said Thomas Crowther, a postdoctoral fellow at the Yale School of Forestry & Environmental Studies and lead author of the study. “Texture overrode the effects of all the other variables that we thought might be important, including temperature, moisture, nutrient concentrations, and soil pH.”

...A serious consequence of deforestation is extensive loss of carbon from the soil, a process regulated by subterranean microbial diversity. Drastic changes to the microbial community are expected to allow more CO2 to escape into the atmosphere, wi
th the potential to exaggerate global warming.

...According to the researchers, particles in fine, clay-like soil seem to have a larger surface area to bind nutrients and water. This capacity might buffer soil microbes against the disturbance of forest removal, they said. In contrast, sandy soils have larger particles with less surface area, retaining fewer nutrients and less organic matter....

This heat map shows the areas of the United States where the soil microbial biomass is susceptible to changes in vegetation cover. From the Yale News website

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