The pith helmet set
An ecologist at Washington University in St. Louis has co-authored a new book that is forcing the pith helmet set to "think outside the helmet."
Jonathan M. Chase, Ph.D., assistant professor of biology at Washington University and Mathew A. Leibold, Ph.D., associate professor of integrative biology at the University of Texas at Austin, are the authors of Ecological Niches. In this work they take on one of the tenets of ecology, niche theory, which holds that species evolve and thrive because of their particular environment and what activities they do to shape that environment, providing them their niche, if you will.
In the book, though, the authors say the old ecological niche theory has about as much relevance to modern ecology as "old Europe" does to the Bush administration.
"We're trying to resurrect niche theory in the modern ecological world," said Chase. "The old theory is based on a species' ability to carve out its own ability to survive, but that is based on species living in a closed and unchanging community.
"But Nature is more variable than the classic models. There are droughts, for example, rainy years, heterogeneous landscapes, and habitats that are disturbed such as wave-swept shores and habitats with frequent wildfires, to name just a few. We think we need a niche theory that incorporates that variability.'
A recent paper published in Ecology Letters by Chase and his wife, Tiffany Knight, Ph.D., a post-doctoral researcher at the National Center for Ecological Analysis and Synthesis in Santa Barbara, California, illustrates the variability of Chase's niche concept. They took the old saw that rainy weather is the cause of increased mosquito populations and instead showed that the previous year's drought is the cause of high mosquito populations coming out of wetlands in the following year. This is because some wetlands, which are the home to mosquito larvae, dry during drought years, drastically reducing mosquito predators-- from fish to water beetles--and competitor species such as snails, tadpoles, and zooplankton.
Ecology presumes that for species to live in the same environment, species have to be different. But the traditional niche theory cannot explain the diversity of tropical rain forests or coral reefs, where hundreds of species appear to be essentially the same.
"Beyond variability and abiotic effects, scale has to be incorporated in this new synthetic niche theory that we propose" Chase said. "We need to look at the world from a macroscope instead of a microscope, from an airplane instead of looking up in a forest. Part of the problem that ecologists have had is we're looking at systems that occur on timescales larger than our own. It's hard to understand the factors that influence forest diversity when the changes are occurring over hundreds to thousands of years
The next millennium will see continued changes in global climate, species extinctions, and invasive species along with the burgeoning human population encroaching on almost all natural areas. "We think ecology is poised to be one of the most important of the biological disciplines", Chase said. "What we hope the book will do is create a synthetic framework that can traverse across scales of ecology and provide a solid foundation for future studies".
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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