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YORK UNIVERSITY RESEARCHERS PUBLISH BREAKTHROUGH ARTICLE IN U.K.'S NATURE MAGAZINE TORONTO, February 12, 1997 -- York University student and professor have masterminded a new biological theory that is shaking up the scientific community after being published in one of the most prestigious science journals in the world. In a breakthrough paper published recently by Nature magazine, York PhD student Jeremy Kerr, 25, and his supervisor, biology professor Dr. Laurence Packer, have challenged the commonly-held belief that heat energy is the ultimate reason there are more species of animals in warm regions than in cold. Nature, a cutting-edge scientific magazine, based out of London, England, has a 90 per cent rejection rate for all research papers submitted. Articles that make it onto the pages of Nature undergo extreme scrutiny and face a gruelling review process. Kerr and Packer's paper is important because it offers another clue in the scientific debate about why the number and variety of species increase the further one gets from the Earth's poles. The paper, titled "Habitat heterogeneity as a determinant of mammal species richness in high energy regions," disputes the prevailing theory about why warmer climates are more hospitable to more species. "This type of research is particularly interesting to me because it has implications for other fields and for our future as well," said Kerr, the lead researcher on the project. "I enjoy doing research and feel that I'm doing something useful in pursuing this work. That's what is great about being an ecologist." The paper does not dispute the existence of a greater variety of species in warm regions, but it does challenge the reason for it, poking holes in an established theory known as the "energy species-richness (ESR) hypothesis." The ESR hypothesis, which was put forward in two papers in 1987 and 1991 by Prof. David J. Currie of the University of Ottawa, argues that the diversity of mammals in North America bears a direct relationship to the availability of energy (heat). This theory is the pre-eminent hypothesis among ecologists in explaining the greater diversity of animals and plants in tropical regions. Kerr and Packer's findings conclude that although the ESR hypothesis is true in colder parts of North America, this relationship disappears as you move south. In other words, there is a threshold at which energy limits species diversity, and this threshold occurs around the Canada-U.S. border. "We have found that in the cool regions of North America, there's a really strong relationship between energy availability and the number of species, but when you move southward, this hypothesis is irrelevant," Kerr said. "In the warm regions, the ESR hypothesis is not statistically significant." Kerr and Packer argue that it is topographic variation, not heat, that causes the richness of mammal species in the southern parts of North America. They suggest that in warmer parts of North America, which are higher energy regions, rolling hills and mountains promote greater diversity in mammals. "Energy was previously believed to determine the richness patterns, but that isn't the case," Packer said. "In the south, there is a strong relationship between the number of species and the topography. The ESR hypothesis is no longer an adequate explanation. I'm not sure we have found the grand hypothesis of ecology, but I do think we have found a striking and powerful relationship (between topography and richness) that no-one has noticed before, and made a significant step in figuring out what is going on." The article is already making waves. Science News has published a recent synopsis on the research called "Another clue to where the species are." "We fully expect there will be prominent scientists who disagree vociferously, but it is crucial for free and open discussions to take place," Kerr said. "Any disagreement will have to be backed up with more data and more analysis." Kerr said his results will have implications for a number of fields outside of biology. "If, as our research suggests, the ESR hypothesis is no longer true, we may be looking at some truly massive changes in the way mammals interact with their environment. The results may cause concern among scientists, politicians, and the public, particularly around the issue of climate change." Although the paper deals with data from mammals only, it is likely to hold true for other organisms such as insects, Packer said. A sophisticated computer program at York University was used to examine patterns of mammal diversity on a continental scale. The research took about a year to complete, and will contribute to a partial fulfilment of Kerr's degree requirements for his PhD. Kerr earned an undergraduate degree (BSc) from the University of Ottawa. He is originally from Kanata, Ont. Kerr now holds a doctoral fellowship with the Natural Sciences and Humanities Research Council of Canada (NSERC), and is the 1996 recipient of the Dean's Academic Excellence Award for Biology in York's Faculty of Pure and Applied Science. Packer has been teaching at York since 1988 and is cross-appointed to the Department of Biology (Faculty of Pure and Applied Science) and the Faculty of Environmental Studies.
For more information, call:
Jeremy Kerr
Laurence Packer
Mary Ann Horgan
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