Macroecology: Theory and TestsEPA Grant Number: U916243
Title: Macroecology: Theory and Tests
Investigators: Ostling, Annette
Institution: University of California - Davis
EPA Project Officer: Graham, Karen
Project Period: January 1, 2003 through January 1, 2006
Project Amount: $110,266
RFA: STAR Graduate Fellowships (2003) Recipients Lists
Research Category: Fellowship - Terrestrial Ecology and Ecosystems , Academic Fellowships , Ecological Indicators/Assessment/Restoration
The objectives of this research project are to: (1) identify the key species distribution properties behind observed macroecological patterns; and (2) uncover the dominant processes molding species distribution properties, and ultimately, observed patterns.
Anthropogenically induced global change has triggered unprecedented rates of decline in biodiversity and caused widespread changes in the global distribution and abundance of organisms. This trend may have significant negative consequences for the services that humans derive from ecosystems. A research frontier in ecology that is pivotal to forestalling this trend and its negative consequences is the understanding of phenomena that are characteristic of entire ecosystems or communities. My research is aimed at understanding these "macroecological" phenomena, such as the way diversity scales with area, and the relative abundance of species. In particular, my research has two goals.
My approach consists of developing and testing two simple theories—one for each of the two goals just described—and building on these simplified, or "null" theories to create more robust theory. The first of the two null theories is based on a hypothesis about the spatial distribution of species, namely that it has a fractal, or self-similarity property that yields observed power-law patterns. The second theory is based on a mechanistic null hypothesis, namely that communities are assembled primarily by dispersal, and that niche differences between species play a minimal role. Neither of these hypotheses is expected to hold for all ecosystems, but each provides a powerful framework for making quantitative, testable predictions. I will further develop the suite of predictions that can be made from each of these existing theories, and test each theory's predictions on available data from a tropical forest, and from a serpentine grassland. These two systems are characterized both by different processes, and by different macroecological patterns, and hence provide a balanced framework in which to test macroecological predictions.
Through these tests, and through the development and testing of more complex theories, I will try to glean the importance of species distribution properties and processes ignored by these null theories in determining macroecological patterns.