RUI: Competitive Co-Existence of Two Predators in a Spatially Patterned Landscape

9527710研究大豆田不同耕作方式对两种狼蛛生存和共存的影响。我们将检验这两个在竞争能力、定植能力和寿命方面不同的蜘蛛物种共存取决于其栖息地的碎片化和干扰程度的假设。这两种蜘蛛更喜欢土壤表面的一片片植物残渣--这是保护性耕作措施下大豆田的一个特征。我们将监测翻耕和免耕大豆田中的蜘蛛，并通过局部耕作或增加覆盖来操纵它们的环境空间格局。这些操作将使我们能够了解栖息地破坏和碎片化如何改变这两个物种之间的相互作用，并确定这种相互作用导致局部灭绝的情况。实验数据将被用来建立一个计算机模型，将我们对物种共存的理解扩展到更长的时间框架和更一般的情况。蜘蛛群落种类繁多，占大豆田捕食性动物群的近50%，但对其了解甚少。了解蜘蛛在常规耕作和免耕大豆田中的活动和相互作用，是了解耕作措施对大豆这一重要作物影响的关键一步。

9527710 Rypstra This research focuses on the effect of tillage practices in soybean fields on the survival and coexistence of two species of wolf spider. We will test the hypothesis that the coexistence of these two spider species differing in competitive ability, colonization ability, and longevity depends on the degree of fragmentation and disturbance in their habitat. The two species of spider prefer patches of plant debris on the soil surface - a feature of soybean fields maintained under conservation tillage practices. We will monitor the spiders in tilled and untilled soybean fields and manipulate the spatial pattern of their environment by localized tilling or addition of mulch. These manipulations will enable us to understand how habitat destruction and fragmentation change the interaction between the two species and determine the situations where the interaction results in localized extinction. Empirical data will be used to build a computer model to extend our understanding of species coexistence to longer time frames and more general situations. The spider community is diverse and constitutes nearly 50% of the predatory fauna in soybean fields, but it is poorly understood. Understanding the activities and interactions of spiders in conventional till and no-till soybean fields is a critical step towards understanding the effect of tillage practices on this important crop.