Collaborative Research: Testing the Role of Resource Heterogeneity and Clonal Integration on Plant Diversity in Grasslands

非技术摘要（200字）“合作研究：测试资源异质性和克隆整合对草原植物多样性的作用”PIs: KL Gross, GG Mittelbach, HL Reynolds （NSF提案#0235699）什么决定了一个地区共存物种的数量是生态学家长期存在的问题。这对植物群落来说尤其具有挑战性，因为植物需要相似的资源，因此我们预计共存物种的数量会受到竞争的强烈限制。解释植物群落高度多样性的一个重要但很少得到验证的假设是，不同斑块间资源水平的变化（即空间资源异质性）可能调节物种多样性。目前，我们正在密歇根草原进行大规模的田间实验，通过同质或异质施肥来增加土壤资源水平，以验证这一假设。这种操作与物种（种子）添加处理相结合，以测试物种入侵这些草地群落的能力在不同的营养制度下是否会发生变化。在这次更新中，我们将继续关注植物物种多样性的变化，以响应我们对营养斑块和潜在物种入侵的处理。我们还将建立一个新的实验，在这个实验中，我们将确定克隆植物——通过产生营养芽生长的物种——的存在是否会影响非克隆物种对土壤资源异质性的响应能力。

Non Technical Summary (200 words) "Collaborative Research: Testing the Role of Resource Heterogeneity and Clonal Integration on Plant Diversity in Grasslands"PIs: KL Gross, GG Mittelbach, HL Reynolds (NSF proposal #0235699)What determines the number of coexisting species in a local area is a long-standing question for ecologists. This is particularly challenging for plant communities because plants require similar resources and so we would expect the number of coexisting species to be strongly limited by competition. One important, but rarely tested, hypothesis to explain the high diversity of plant communities is that variation in resource levels across different patches (i.e., spatial resource heterogeneity) may regulate species diversity. We are currently testing this hypothesis in a large-scale field experiment in Michigan grassland by experimentally increasing soil resource levels through fertilization in either a homogeneous or heterogeneous fashion. This manipulation is combined with a species (seed) addition treatment to test if the ability of species to invade these grassland communities changes under different nutrient regimes. In this renewal, we will continue to follow changes in plant species diversity in response to our treatments of nutrient patchiness and potential species invasion. We also will establish a new experiment in which we will determine whether the presence of clonal plants - species that grow by producing vegetative shoots - influences the ability of non-clonal species to respond to heterogeneity in soil resources.