Dissertation Research: Investigations of the Relationship Between Biodiversity and Ecosystem Function by Examination of Acidified Streams

9701332刘易斯虽然生物多样性仍然是许多生态研究和保护工作的重点，但它与生态系统功能的关系仍然没有得到解决。文献提供了生物多样性与生态系统功能之间相互依存和独立的例子。本项目的目的是检验以下三个假设：（1）在一个递增压力的生态系统中，一个给定的生物区室将首先表现出生物多样性的抑制，随后表现出生物量的抑制：（2）生态系统功能的抑制主要与生物量的抑制有关，而与生物多样性本身无关;以及（3）根据一系列可预测的阈值，生物量的抑制在生物区室中不同：多细胞生物体单细胞自养生物体微生物分解者。这些假设将在一组溪流上进行测试，其中一些溪流已受到酸性矿井排水的影响。这些流是极好的模型系统，因为它们包括多种应力的宽梯度（低pH、高浓度金属、氧化物沉积），其中每一种应力都是可量化的。这些流的试点研究是一致的三个假设。该项目将侧重于扩大关于底栖昆虫和附着生物的资料，以检验各种假设，并利用分子技术获得关于微生物分解室的可比资料。

9701332 Lewis While biodiversity continues to be the focus of many ecological studies and conservation efforts, its relation to ecosystem function remains unresolved. The literature provides examples of both interdependence and independence between biodiversity and functioning of ecosystems. The purpose of this project is to test three hypotheses, as follows: (1) a given biotic compartment in an incrementally stressed ecosystem will show suppression of biodiversity first, and suppression of biomass subsequently; (2) suppression of ecosystem function is primarily related to suppression of biomass, rather than to biodiversity per se; and (3) suppression of biomass differs among biotic compartments according to a predictable series of thresholds: multicellular organisms unicellular autotrophs microbial decomposers. These hypotheses will be tested on a group of streams, some of which have been stressed by acidic mine drainage. These streams are excellent model systems because they include a wide gradient of multiple stresses (low pH, high concentration of metals, oxide deposition), each of which is quantifiable. Pilot studies on these streams are consistent with the three hypotheses. The project will focus on expansion of the information on benthic insects and periphyton as necessary to test the hypotheses, and use of molecular techniques to obtain comparable information on microbial decomposer compartments.