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 | Marcel Holyoak
Deptartment of Environmental Science and Policy, University of California, Davis, United States of America | | | Faculty Member: Ecology > Community Ecology & Biodiversity [ since 1 February 2006 ] |
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Marcel Holyoak sponsors free access to F1000 for Center for Scientific Research and Higher Education of Ensenada CICESE, Ensenada, Mexico. Supporting F1000's initiative to make itself available to scientists in all countries, including free access to developing countries (more details). | Biography
Contact details:
Department of Environmental Science and Policy
University of California
1 Shields Avenue, Davis, CA 95616, USA
Tel: +1 530 754-7046
Fax: +1 530 752-3350
Email: maholyoak@ucdavis.edu
Research interests:
The spatial ecology of populations and communities. What is the role of spatial structure in promoting the persistence and coexistence of species? This question merits examination at a variety of levels, ranging from the effects of habitat fragmentation and loss on wildlife conservation, to the population and metapopulation dynamics of individual species, and finally to whole food webs, communities and even spatially-connected "metacommunities". A pluralism of approaches and study systems is also required to address such systems. Conservation questions in the lab focus on rare or imperiled plants and animals, whereas metapopulation and metacommunity questions have used birds, insects in the field and protists in laboratory microcosms. Methods used include simulation models, a broad range of statistical methods and modeling, microcosm experiments, field surveys and geographic information systems.
Conventional explanations for observed levels and patterns of species diversity often assume that communities are closed, isolated entities. For instance, the equilibrium theory of island biogeography assumes a fixed mainland pool of species that randomly arrive on islands and assemble into local communities. This is at odds with the idea that the dynamics of species moving among islands or habitat areas might contribute to species diversity, as captured in metapopulation theories. Metapopulations consist of populations of populations, which go extinct and are reformed by colonization from extent populations. If such spatial dynamics are important for individual species, it follows that a complete explanation of species diversity should entail similar dynamics. It is also possible that the interactions among species, food web structure, and even the functioning of entire ecosystems are influenced by spatial dynamics. A growing body of work addresses such ideas. I edited the first book about metacommunities with Mathew Leibold and Bob Holt in 2005 (University of Chicago Press), and have collaborated on tests of new theories about the role of spatial structure in promoting species diversity.
A somewhat separate theme has been to evaluate the spatial population and metapopulation dynamics of both single species and predator-prey interactions by using protists in laboratory microcosms as a model study system. Using protozoa with generation times of just hours theories that entail long-term demography and even species' persistence can be tested. My research group, collaborators and I have conducted a variety of relatively precise quantitative tests of modern ecological theories, of the kind that would be impossible to conduct in field systems. Such laboratory experiments help us bridge between completely mathematical theories where we can control everything and the large scale natural field processes that we are interested in but cannot collect sufficient information about to study.
I am also fascinated by biostatistics, which form an essential bridge between observational and experimental data and ecological hypotheses and theories. Starting from a PhD in time series analysis and statistical modeling to explore feedback processes in long-term records of animal population abundances I branched out to consider spatial processes. Spatial data are more information rich than long-term data and yet they contain complex correlational problems that invalidate many traditional statistical methods. A growing theme in my research is how to relate large scale environmental data to organismal abundance and occurrence data. Finally, a strong interest in birds and natural history keeps me connected to nature. | Home page
http://www.des.ucdavis.edu/faculty/holyoak/ |
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