Dissertation Research: Regional/historical Influences and Top-down vs. Bottom-up Processes in Arthropod Community Structure

0073055泰勒掠食者（"自上而下"）和资源（"自下而上"）的强大直接影响的证据正在从数学模型和简化的组合中出现。来自自然群落的数据是必要的，以提高我们对它们在多个尺度上的综合影响的理解。 使用大规模的调查结合在一个单一的网站与操作的现场实验，该项目探讨了夏威夷桃金娘树Metrosideros polymorpha的鸟类捕食者和节肢动物组合的营养相互作用。 在四百万年的火山基质年龄梯度中，养分的可用性以单峰方式变化。 节肢动物密度Metrosideros跟踪整个岛链的这种关系，这表明了强大的影响力的资源系统。 物种多样性随地质年龄的增长而增加，与密度无关。 这些关系将在一个年轻的玄武岩熔岩流（120 y.o.）Metrosideros植物群落营养有限，对施肥的反应是生产力增加十倍。 脊椎动物捕食者（鸟类）将被排除在外，大的地块将在一个完全交叉的良好复制的设计施肥。 拟议的研究计划结合了自然模式的观测数据的规模和观点与控制现场实验，从而扩大了单独从任何一种方法的推断范围。

0073055TaylorEvidence of strong direct effects of predators ("top-down") and resources ("bottom-up") are emerging from mathematical models and simplified assemblages. Data from natural communities are necessary to improve our understanding of their combined effects over multiple scales. Using large-scale surveys combined with manipulative field experiments at a single site, this project examines the trophic interactions of avian predators and arthropod assemblages of the Hawaiian myrtaceous tree Metrosideros polymorpha. Across a four million-year gradient of volcanic substrate age, nutrient availability varies in a unimodal fashion. Arthropod densities on Metrosideros track this relationship across the island chain, suggesting a strong influence of resources to the system. Species diversity accumulates with geological age and is independent of density. These relationships will be evaluated on a young basaltic lava flow (120 y.o.) where Metrosideros plant communities are nutrient limited and respond to fertilization with a tenfold increase in productivity. Vertebrate predators (birds) are to be excluded and large plots will be fertilized in a completely crossed well-replicated design. The proposed research program combines the scales and perspectives of observational data on natural patterns with controlled field experiments, thereby expanding the scope of inference from either approach alone.