Dissertation Research: The Distribution of a Grasshopper Species Among New England Old Fields: Population Ecology Along an Environmental Gradient

该方案结合种群生态学和群落生态学的组成部分，研究限制新英格兰旧田蚱蜢物种分布和丰度的生物和环境因素。本研究将确定非生物和生物生态因素的变化如何影响黑加的种群生态和随后的分布。实地调查表明，这种蚱蜢是一种多面手的食草动物，它喜欢草资源，仅限于草覆盖面积小于60%的旧田。初步和正在进行的研究表明，竞争和捕食似乎不是该物种在这些旧田的重要限制因素。在此基础上，将进行两个实验。第一组实验验证了鸟类和小型哺乳动物捕食者是M. femurrubrum的主要限制因素的假设。第二组实验验证了这种蚱蜢的分布受到产卵地点选择和卵发育成功的限制的假设。总体而言，本研究针对一种在受人类活动严重影响的景观中具有广泛和经济重要性的昆虫分布的主要假设，使本研究与人类改变景观背景下的基础生态学相关。

9801665 Schmitz This proposal integrates components of population ecology and community ecology to investigate the biological and environmental factors that limit the distribution and abundance of a grasshopper species in New England old fields. This research will identify how variation in abiotic and biotic ecological factors shape the population ecology and subsequent distribution of Melanoplus femurrubrum. Field surveys demonstrated that this grasshopper is a generalist feeder that prefers grass resources that is restricted to old fields with less than 60% grass cover. Preliminary and ongoing research have indicated that competition and predation do not appear to be significant limiting factors for this species in these old fields. Based on this, two experiments will be performed. The first proposed set of experiments tests the hypothesis that bird and small mammal predators are the major limiting factors of M. femurrubrum. The second set of experiments tests the hypothesis that the distribution of this grasshopper is limited by the success of oviposition site selection and egg development. Overall, this research targets major hypotheses about the distribution of an insect of wide range and economic importance in a landscape heavily influenced by human activities, making this study relevant to basic ecology in the context of a human altered landscape.