Understanding and mitigating the impacts of altered temperature and precipitation regimes on the function and biodiversity of rangeland communities

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Canada contains 22,000,000 ha of land dedicated to range and forage production.  This land supports 4M cow/calf pairs and overgrazing has resulted in less than 50% of this area listed as in "good" condition.  Improving rangeland condition provides direct economic benefits and since native range stores more C than pasture, this will also lead to increase C storage.  A healthy rangeland stores equivalent C per ha as forest, and since this C is primarily belowground, it is at a lower risk of release during fires.  Unfortunately, we have a limited understanding of the belowground processes that drive rangeland dynamics, and a general lack of information on how climate change will impact the sustainability of these systems.  Understanding the climate-grazing interactions in rangelands has the potential to (1) increase C storage, (2) enhance biodiversity and ecosystem functioning, and (3) provide economic returns.        To mitigate the potential impacts of climate change on the biodiversity and sustainable production of Canada's rangelands, it is essential to gain a mechanistic understanding of the links between temperature, precipitation, soil chemistry, microbial and invertebrate diversity and activity, primary production, and grazing.  We will conduct experiments in the Parkland regions of Alberta, Saskatchewan, and Manitoba.  At each location, we will establish plots subjected to combinations of defoliation, warming, and precipitation treatments for three growing seasons.  We will measure primary productivity and range health, with a particular emphasis on belowground dynamics.  We will use mini-rhizotrongs to allow for enhanced accuracy in estimations of primary productivity and carbon flow. We will also measure changes in microbial and invertebrate communities, litter decomposition, and C and N cycling and explore linkages among these processes.  From these data, we will identify a set of management recommendations for this sector of the agricultural community on how to alter grazing regimes to mitigate the varied impacts of climate change.