Climate Change Boosts Then Quickly Stunts Plants, Decade-long Study Shows

 

“Faster nitrogen turnover stimulated nitrogen losses, likely reducing the effect of warming on plant growth,” Hungate said. “More generally, changes in species, changes in element cycles–these really make a difference. It’s classic systems ecology: the initial responses elicit knock-on effects, which here came back to bite the plants. These ecosystem feedbacks are critical–you can’t figure this out with plants grown in a greenhouse.”

 

http://www.skepticalscience.com/Climate-change-plants_NSF.html

 

Source Paper:

Zhuoting Wu, Paul Dijkstra,George W. Koch,and Bruce A. Hungate, Biogeochemical and ecological feedbacks in grassland responses to warming, Nature Climate Change(2012) doi:10.1038/nclimate1486

Received 01 June 2011 Accepted 08 March 2012 Published online 08 April 2012

 

Abstract

 

Plant growth often responds rapidly to experimentally simulated climate change1, 2. Feedbacks can modulate the initial responses3, but these feedbacks are difficult to detect when they operate on long timescales4. We transplanted intact plant–soil mesocosms down an elevation gradient to expose them to a warmer climate and used collectors and interceptors to simulate changes in precipitation. Here, we show that warming initially increased aboveground net primary productivity in four grassland ecosystems, but the response diminished progressively over nine years.

Warming altered the plant community, causing encroachment by species typical of warmer environments and loss of species from the native environment—trends associated with the declining response of plant productivity.

Warming stimulated soil nitrogen turnover, which dampened but did not reverse the temporal decline in the productivity response. Warming also enhanced N losses, which may have weakened the expected biogeochemical feedback where warming stimulates N mineralization and plant growth1, 5, 6.

 

Our results, describing the responses of four ecosystems to nearly a decade of simulated climate change, indicate that short-term experiments are insufficient to capture the temporal variability and trend of ecosystem responses to environmental change and their modulation through biogeochemical and ecological feedbacks.

 

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1486.html