The causes and consequences of diversity in ecological communities

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My long-term objectives are to determine how habitat loss and degradation affect ecological communities, and how those changes in ecological communities affect ecosystem structure and  function.  I will do this using large-scale experiments and research synthesis techniques.  In the short-term I will address three questions, 1. Are biotic interactions important in driving population and community dynamics?; 2.  What are the primary causes of global amphibian declines?; 3.  How do roads and road construction affect pond-breeding amphibian communities?To answer the first question I will use two approaches.  The first involves whole-pond experiments where 6 ponds are split by a large impermeable curtain extending from the surface of the pond to the pond bottom. All amphibian species are excluded from one half of 6 replicate ponds, but allowed access in the other half.  Then we monitor water quality and the abundance of aquatic invertebrates and plants in both halves of the ponds to see if the amphibian communities play an important role in pond dynamics.  The second approach uses publicly available datasets to examine covariance among species in ecological communities.  Using a simple statistical procedure we test for negative covariance among species in natural communities, which we would expect if competition is an important driver of population and community dynamics.To answer the second question we will use a dataset of more than 1000 amphibian population time series and examine the correlation between amphibian abundance and suspected mechanisms of amphibian decline like UV-B ray exposure and habitat loss and degradation.To answer the third question we have designed a Before-After-Control-Impact (BACI) experiment to monitor amphibian populations at ponds near proposed road construction areas, both before and after road construction.  We will compare changes over time in those ponds with changes in similar ponds that are not near road construction sites.