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

加拿大有22，000，000公顷土地专门用于牧场和饲料生产。 这片土地支持400万对母牛/小牛，过度放牧导致该地区不到50%的地区被列为“良好”状态。 改善牧场条件提供了直接的经济效益，由于天然牧场储存更多的碳比牧场，这也将导致增加碳储存。 一个健康的牧场每公顷储存相当于森林的碳，由于这种碳主要在地下，它在火灾期间释放的风险较低。 不幸的是，我们对驱动牧场动态的地下过程的了解有限，并且普遍缺乏关于气候变化将如何影响这些系统的可持续性的信息。 了解牧场的气候-放牧相互作用有可能（1）增加碳储量，（2）增强生物多样性和生态系统功能，（3）提供经济回报。 为了减轻气候变化对加拿大牧场的生物多样性和可持续生产的潜在影响，必须从机理上了解温度、降水、土壤化学、微生物和无脊椎动物多样性和活动、初级生产和放牧之间的联系。 我们将在阿尔伯塔、萨斯喀彻温和马尼托巴的帕克兰地区进行实验。 在每个地点，我们将建立样地进行落叶，变暖和降水处理的三个生长季节的组合。 我们将测量初级生产力和范围健康，特别强调地下动态。 我们将使用微型根管，以提高初级生产力和碳流量估计的准确性。我们还将测量微生物和无脊椎动物群落，凋落物分解，C和N循环的变化，并探索这些过程之间的联系。 从这些数据中，我们将确定一套管理建议，为这一部门的农业社区如何改变放牧制度，以减轻气候变化的各种影响。

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.