Organizational Complexity in Ecological Foodwebs: Experimental Analysis of Interaction Strength in an Old-Field System

[508604] Schmitz本研究将评估直接和间接的物种相互作用在构建陆生原生地食物网中的重要性。对物种相互作用的深入了解将通过在涉及植物、昆虫食草动物（蚱蜢、蝈蝈和甲虫）和食肉动物（狩猎蜘蛛）的自然野外环境中进行详细的工作来获得。这项研究将测试食物网生态学中的一个关键假设，即一个物种对另一个物种的影响强度将取决于食物网的物种组成，以及两个物种通过它们与系统中其他物种的联系而直接和间接相互作用的方式。将进行实地实验，以精确可靠地量化物种相互作用的种类、它们的优势以及物种相互作用所通过的途径网络。实验食物网由不同数量的原野草本植物、草食昆虫和蜘蛛组成，在野外的封闭笼子中进行组装，以量化物种多样性增加对食物网中物种相互作用的影响。实验还将评估，如果食物网结构通过物种移除而减少，食物网动态是否会改变。这项研究将提供重要的信息，让我们了解自然老生境系统中的物种是如何联系在一起的，也将深入了解当这些联系被自然或人为干扰破坏时会发生什么。这一信息对保护生物多样性至关重要。许多生态学家提出，生物多样性的减少破坏了物种联系网络，可能对自然食物网的动态产生严重影响。

9508604 Schmitz This study will evaluate the importance of direct and indirect species interactions in structuring a terrestrial old-field food web. Insight into species interactions will be obtained through detailed work in natural field settings involving plants, insect herbivores (grasshoppers, katydids, and beetles) and carnivores (hunting spiders). The study will test a key hypothesis in food-web ecology that the strength of effects of one species on another will depend on species composition of the food web and the direct and indirect ways the two species interact through their linkages will other species in the system. Field experiments will be conducted to quantify precisely and reliably the kinds of species interactions, their strengths and the network of pathways through which the effects of species interactions pass. Experimental food webs with varying numbers of species of old-field herbs and grasses, insect herbivores and spiders will be assembled in enclosure cages in the field to quantify the effect of increasing species diversity on species interactions in a food web. The experiments will also evaluate whether or not food-web dynamics become altered if food-web structure is reduced through species removals. This research will provide important information on the way species in natural old-field systems become linked together and it will offer insight into what happens when these linkages are disrupted by natural or human disturbances. This information is crucial for the conservation of biological diversity. Many ecologists have suggested that a reduction in biodiversity that disrupts the network of species linkages can have serious impacts on the dynamics of natural food webs.