Collaborative Research: Compensatory VS Amplifying Effects of Community Structure on Ecological Systems in Response to Environmental Fluctuations

University Of Texas At Austin, Austin TX

Investigators

Abstract

Intellectual merit: The dynamics of ecosystem attributes are regulated by the dynamics of the interacting species within ecosystems, yet little is known about how this occurs. Theoretical work suggests that the dynamics of ecosystem attributes will depend strongly on how the dynamics of species with similar effects on these attributes are related. Some studies have suggested that compensatory dynamics among such species involving negative correlations in their fluctuations are important in stabilizing ecosystem fluctuations. However there are several reasons to think that such compensatory dynamics only occur under limited conditions and that synchronous dynamics (positive correlations in species fluctuations) are also likely. Such synchronous dynamics would tend to amplify oscillations in ecosystem attributes. The conditions under which compensatory vs synchronous dynamics occur is poorly understood and not well documented. A hypothesis states that compensatory dynamics depend on three factors: First, species with similar effects on ecosystem attributes must show trade-offs that are sufficient in magnitude to allow the possibility of compensation. Second, the environment must fluctuate appropriately with respect to factors involved in these trade-offs. Third, species that show these trade-offs must coexist only if they are not too similar to each other. This set of ideas and hypotheses will be tested by experimentally manipulating the diversity, composition and food-web structure of pond communities subjected to different types of external recurrent fluctuations. This work will provide important insights into the ways that various aspects of community structure affect ecosystems. This is of key interest for both basic science and for informing society about the potential ecosystem consequences of human alteration of biological communities and environmental change. Broader impacts: This research will contribute to education and society by: 1) Being integrated into the teaching of undergraduate students at OWU (a non-PhD granting institution) and UT. 2) Directly involving and mentoring selected students from these institutions into field research. 3) Directly supporting graduate students and post-docs involved the proposed research or in closely related projects of their own design. 4) All of these participants will be expected to be involved in the dissemination of results via publications and presentations at meetings. 5) Developing new statistical methods for analysis of ecological data and making these methods available to others (via the web). 6) Making data available for research purposes through the Environmental Statistics Center (an EPA-funded center for statistical research on environmental problems at the University of Chicago). Seeking ways to communicate results that might inform societal environmental concerns via networking with appropriate organizations such as NCEAS, Resilience Alliance, ESA etc.