DURHAM, N.C. -- A new study led by Duke University researchers finds that restoring degraded wetlands -- especially those that had been converted into farm fields -- actually decreases their soil bacterial diversity.
But that's a good thing, say the study's authors, because it marks a return to the wetland soils' natural conditions.
"It sounds counter-intuitive, but our study shows that in restored wetlands, decreased soil bacterial diversity represents a return to biological health," said Wyatt H. Hartman, a Ph.D. candidate in wetlands and environmental microbiology at Duke's Nicholas School of the Environment.
"Our findings are novel because they are the opposite of the response seen in terrestrial ecosystems, where restoration improves conditions from a more barren, degraded state," said Curtis J. Richardson, director of the Duke University Wetland Center and professor of resource ecology at the Nicholas School. Richardson is Hartman's faculty adviser.
Their report on the study will be published online this week by Friday in the Proceedings of the National Academy of Sciences.
Soils in undisturbed wetlands present harsh conditions, with elevated acidity and low oxygen and nutrient availability in which fewer bacterial groups can survive and grow, they explained. In comparison, former wetlands that have been drained, limed and fertilized for farming host greater soil bacterial diversity because they present conditions more suitable for bacterial growth.
"The bacterial communities in these fields almost resemble those found in wastewater treatment plants," Hartman noted.
Soil bacteria are essential to wetland functions that are critical to environmental quality, such as filtering nutrients and storing carbon. "The mixture of bacterial groups in wetland soils can reflect the status of wetland functioning, and the composition of these populations is as telling as their diversity," Richard
|Contact: Tim Lucas|