July 03, 2014
New research from Western University explores how climate change may fundamentally change Canada's northern wetlands. In a paper released in the journal Global Change Biology, Professors Zoë Lindo and Brian Branfireun from Western's Faculty of Science show that the types of plants that dominate northern peatlands (a type of wetland that accumulates thick layers of organic soil) change significantly at temperatures between four and eight degrees above their normal growing conditions.
At higher temperatures, which reflect changes that are anticipated in northern Canada, a major decline in the normally dominant sphagnum, or "peat” moss, was measured by the researchers during a two-year study. This was contrasted by an increase in two different types of sedges, a plant that resembles grass and usually dominates more nutrient-rich wetlands. These warmer temperatures were more favourable for sedges, which were also fertilized by higher carbon dioxide concentrations in air.
"Changes in the plant community affect many other ecosystem processes, so a loss of Sphagnum moss is particularly concerning," explains Lindo, an Assistant Professor in Ecology at Western's Department of Biology and the senior author of the paper. "This is a keystone species for maintaining moisture conditions, preserving habitat for soil organisms and storing carbon because it resists decomposition."
The experiment was conducted at Western's Biotron Experimental Climate Change Research Centre, where nearly 100 mini-wetlands were transplanted from a field site north of Lake Superior to its rooftop greenhouses. For nearly two years, the mini-wetlands were subjected to a range of experimental moisture, temperature and carbon dioxide concentrations to mimic future climate conditions.
"Without the facilities in the Biotron, this kind of experiment would not be possible," says Branfireun, the Canada Research Chair in Environment and Sustainability who serves as Director of the Biotron and is also a co-author on the paper. "Nature is highly variable from year to year, making it difficult to confidently identify trends like the ones that we have found under the controlled environments in the Biotron."
The study is part of the doctoral research program of Catherine Dieleman, a PhD Candidate in Western's Department of Biology and lead author of the resulting paper. This is the first of a series of publications from this experiment, all of which focus on how climate change may affect plants, soils, and water quality in the north. Jim McLaughlin, Research Scientist at the Ontario Ministry of Natural Resources - Ontario Forest Research Institute in Sault Ste. Marie, is also a co-author on the paper and a project partner.
For information on these research groups you can visit http://publish.uwo.ca/~zlindo/ and ecohydrology.ca or follow the researchers on Twitter @lindolab and @eco_hydrology.
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