Collaborative Research: Linking Environmental Heterogeneityto Foraging Behavior: Plant Community Geometry and Herbivore Functional Response

资源异质性的生态后果取决于资源在空间中的排列方式和寻找资源的生物的功能特性。PI导出了一个草食动物消耗的模型，该模型结合了植物空间排列的变化，以及动物的速度和食物处理能力。该模型提出了以下假设：1)植物群落斑块性的增加导致资源偶遇率随着觅食时间的增加而下降。2)通过增加资源的透明度和规模来对抗遭遇率的下降。(3)当资源偶遇率超过动物食品加工率时，空间格局对摄食率的影响不明显。4)在一定尺度下，空间格局对采食量的影响以中等体型动物最大。为了验证这些假设，PI将在实验室和野外实验中操纵资源的空间格局、资源的可见性和资源的大小。这些实验的结果将对该模型预测消费者摄取率的能力进行评估，并与更传统的预测理论进行比较。PI开发了第一个模型，将资源斑块、资源丰度、食草动物的觅食运动和体型与食草动物的资源获取联系起来。该模型产生了一系列可检验的假设，其中一些是独特的、反直觉的。对这些假设的检验将对草食动物觅食的一般理论提供重要的贡献。该研究结果对放牧系统的景观尺度管理具有重要意义，并对当前许多自然系统中发生的栖息地破碎化的觅食行为有了一般性的理解。

The ecological consequences of heterogeneity in resources depend on the way resources are arranged in space and on the functional properties of organisms seeking them. The PI's derived a model of consumption by herbivores that incorporates variation in spatial arrangements of plants, and velocities and food processing abilities of animals. The model generated the following hypotheses: 1) Increasing patchiness in plant communities causes encounter rate with resources to decline as foraging time increases. 2) The decline in encounter rate is opposed by increasing resource apparency and size. 3) Spatial pattern fails to influence intake rate when resource encounter rate exceeds an animals food processing rate. 4) At a given scale, the influence of spatial pattern on intake rate will be greatest for animals of intermediate body sizes. To test these hypotheses, the PI's will manipulate spatial patterns of resources, resource apparency, and resource size available to herbivores in laboratory and field experiments. Results from these experiments will provide an assessment of the model's ability to predict intake rate of consumers in comparisons with predictions from more traditional predictive theory. %%% The PI's have developed one of the first models that relates resource patchiness, resource abundance, foraging movements of herbivores, and body size to resource acquisition by herbivores. The model has generated a series of testable hypotheses, some of which are unique and counter-intuitive. Tests of these hypotheses will provide an important contribution toward a much needed general theory of herbivore foraging. Results from this research have important implications for landscape scale management of grazing systems, and for a general understanding of foraging behavior in light of the habitat fragmentation currently occurring in many natural systems.