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，以及寻求资源的有机体的功能特性。PI‘s派生了一个食草动物的消费模型，该模型包含了植物空间排列的变化，以及动物的速度和食物加工能力。该模型提出了以下假设：1)随着觅食时间的增加，植物群落中斑块度的增加会导致与资源的相遇几率下降。2)相遇概率的下降与资源的显着性和规模的增加相反。3)当资源相遇率超过动物食物加工率时，空间格局不能影响摄食率。4)在一定尺度下，中等体型动物的采食率受空间格局的影响最大。为了检验这些假设，PI将操纵资源的空间模式、资源表现力以及食草动物在实验室和野外实验中可用的资源大小。这些实验的结果将评估该模型预测消费者摄入量的能力，并与更传统的预测理论的预测进行比较。PI已经开发出最早的模型之一，该模型将资源斑块、资源丰富度、草食动物的觅食活动以及身体大小对食草动物获取资源的影响。该模型产生了一系列可检验的假设，其中一些是独一无二的，与直觉相反。对这些假说的检验将为建立一个亟需的食草动物觅食的一般理论做出重要贡献。这项研究的结果对于放牧系统的景观尺度管理以及根据目前在许多自然系统中发生的生境破碎化对觅食行为的一般理解具有重要的意义。

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.