Ecological Mechanisms and Scaling in Heterogeneous Grassland Ecosystems

拟议的研究将(A)发展将个体对种群和生态系统动态空间变化的反应联系起来的理论；(B)通过试验田研究和模拟模拟来检验这一理论；(C)确定生态特征如何随空间尺度变化，以及是否可以为尺度间的外推界定“规则”；(D)将这项工作扩展到由热带相连物种组成的系统。这项实地研究是在半干旱草原生态系统中进行的，将包括对天牛对“微景观”空间结构的反应以及对更广泛尺度上空间模式变化的反应的实验研究。细微尺度上的个体移动模式将与长距离移动相结合，以确定个人行为如何转化为种群分布。将使用收割机蚂蚁进行实验，以确定生态系统的空间结构如何影响种子的移除和运输。将使用角蜥蜴-蚂蚁和长刺-蝗虫系统来研究相互关联的营养级别之间的比例关系。这项研究直接涉及生态尺度和外推、斑块边界的物质流动、空间模型的经验测试以及景观生态学的实验和理论方法的发展等当前问题。

The proposed research will (a) develop theory linking the responses of individuals to spatial variation in population and ecosystem dynamics; (b) test such theory by experimental field studies and simulation modeling; (c) determine how ecological features vary with spatial scale and whether "rules" can be defined for extrapolating among scales; and (d) extend this work to systems composed of tropically linked species. The field research, conducted in a semiarid grassland ecosystem, will involve experimental studies of responses of tenebrionid beetles to the spatial structure of "microlandscapes" and to variations in spatial patterns at broader scales. Individual movement patterns at fine scales will be coupled with long-distance movements to determine how individual behavior translates into population distribution. Experiments with harvester ants will be used to determine how the removal and transport of seeds are affected by the spatial structure of ecosystems. Scaling relationships among linked trophic levels will be investigated using horned lizard-ant and longspur-grasshopper systems. The research bears directly on current issues in ecological scaling and extrapolation, flows of materials across patch boundaries, empirical testing of spatial models, and the development of an experimental and theoretical approach to landscape ecology.