| Gary G. Mittelbach |
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Professor of Zoology Ph.D. Michigan State University, 1980 W. K. Kellogg Biological Station Research Interests As an ecologist, I am interested in the evolution and maintenance of biodiversity (the variety of life), and in particular, what determines species diversity at different spatial scales. At the local scale, the number and type of species found in a community depends on biotic and abiotic interactions, species sorting, and dispersal of colonists from a regional species pool. At broad spatial scales (regions, continents), we need to consider the factors that drive rates of diversification (speciation and extinction), as well as the dispersal of species between regions. Studying biodiversity at these different spatial scales requires different tools and different approaches. Local communities often lend themselves to experimental manipulation and my current research in this area includes experimental studies in freshwater communities (working with fish and aquatic invertebrates), and a long-term, collaborative study on the effects of resource heterogeneity on species diversity in a terrestrial grassland. To study the causes of biodiversity patterns at broad spatial scales, I work collaboratively with a group of ecologists, evolutionary biologists, and paleontologists, focusing particularly on the evolution of the latitudinal gradient in biodiversity. Below are brief sketches of these research areas and references to recently published papers.
Biodiversity and ecosystem functioning in aquatic communities (Most of this research is done in collaboration with my graduate students, who work with a variety of organisms in different aquatic habitats). Mittelbach, G.G., E. A. Garcia, and Y. Taniguchi. 2006. Fish reintroductions reveal smooth transitions between lake community states. Ecology 87:312-318. Whether communities respond smoothly or discontinuously to changing environmental conditions has important consequences for the preservation and restoration of ecosystems. In this seventeen year study of a Michigan lake, we show that manipulating the fish community from high plantivore density to low planktivore density back to high planktivore density results in dramatic, but smooth transitions between ecosystem states. Wojdak, J.M. and G. G. Mittelbach (2007). Consequences of niche overlap for ecosystem functioning: an experimental test of pond grazers. Ecology 88:2072-2083. We outline an experimental approach for testing how niche complimentarity contributes to positive biodiversity effects on ecosystem functioning and apply this approach in an experimental study with pond grazers (gastropods). Garcia, E.A. and G. G. Mittelbach (2008). Regional coexistence and local dominance in Chaoborus: species sorting along a predation gradient. Ecology 89:1703-1713. By experimentally manipulating fish density in small ponds, we were able to show that variation in predation pressure, in combination with species traits, determines the distribution and local dominance of Chaoborus (phantom midge) species across a landscape of lakes and ponds.
Consequences of resource heterogeneity, productivity, and clonality to species diversity in a low-productivity grassland (in collaboration by Drs. Katherine Gross and Heather Reynolds, plus students and postdocs). Coexistence theory predicts that greater heterogeneity of resources or other fitness-constraining environmental factors will promote species diversity, yet this classic mechanism of coexistence has rarely been tested in manipulative field experiments. We are conducting two large-scale field experiments manipulating soil resource heterogeneity, in combination with species introductions (by seed), and the presence/absence of clonal species, to test this hypothesis in a low productivity grassland in Michigan. Our results show that the large foraging area of clonal plants limits the positive impact of resource heterogeneity on species coexistence. Gross, K.L., G.G. Mittelbach, and H.L. Reynolds. 2005. Grassland invasibility and diversity: responses to nutrients, seed input, and disturbance. Ecology 86:476-486. Reynolds, H.L., G.G. Mittelbach, T.L. Darcy-Hall, G.R. Houseman, and K.L. Gross. 2007. No effect of varying soil resource heterogeneity on plant species richness in a low fertility grassland. Journal of Ecology 95:723-733. Golubski, A.J., K.L. Gross, and G.G. Mittelbach. 2008. Competition among plant species that interact with their environment at different spatial scales. Proceedings of the Royal Society B 275:1897-1906. Golubski, A.J., K.L. Gross, and G.G. Mittelbach. 2010. Recycling-mediated facilitation and coexistence based on plant size. American Naturalist 176:588-600. Eilts, J.A., G.G. Mittelbach, H.L. Reynolds, and K.L. Gross. 2011. Resource heterogeneity, soil fertility, and species diversity: effects of clonal species on plant communities. American Naturalist 177:574-588.
Patterns in Species Diversity The dramatic increase in biodiversity as one moves from the poles to the tropics, generally known as the Latitudinal Diversity Gradient, “..is the major, unexplained pattern in natural history…, one that mocks our ignorance” (Robert Ricklefs). My interest in the latitudinal diversity gradient stems from a general interest in understanding how climate and history affect broad scale patterns in biodiversity, and most of my work in this area is the result of collaborations developed from three working groups supported by the National Center for Ecological Analysis and Synthesis in Santa Barbara, CA. Listed below are some representative publications. Hawkins, B.A., R. Field, H.V. Cornell, et al. 2003. Energy, water, and broad-scale geographic patterns of species richness. Ecology 84:3105-3117 Currie, D.J., G.G. Mittelbach, H.V. Cornell, et al. 2004. Predictions and tests of climate-based hypotheses of broad-scale variation in taxonomic richness. Ecology Letters 7:1121-1134. Mittelbach, G.G., D.W. Schemske, H.V. Cornell, et al. 2007. Evolution and the latitudinal diversity gradient: speciation, extinction and biogeography. Ecology Letters 10:315-331. Schemske, D.W., G.G. Mittelbach, H.V. Cornell, J.M. Sobel, and K. Roy. 2009. Latitudinal variation in the strength of biotic interactions: evidence and consequences for the biodiversity gradient. Annual Review of Ecology, Evolution, and Systematics 40:245-269.
COMMUNITY ECOLOGY TEXTBOOK Much of my time over the last five years has been spent writing a textbook on Community Ecology, which is now finished and available from Sinauer Associates Inc. (April 2012). For more information, including a full table of contents, a downloadable sample chapter on Biodiversity and Ecosystem Functioning, and instructions for ordering or requesting an examination copy, please see the Sinauer web site at (www/sinauer.com). The book is also available from Amazon.com. About the book: Community ecology has undergone a transformation in recent years, from a discipline largely focused on processes occurring within a local area, to a discipline encompassing a much richer domain of study, including the linkages between communities separated in space (metacommunity dynamics), niche and neutral theory, the interplay between ecology and evolution (eco-evolutionary dynamics), and the influence of historical and regional processes in shaping patterns of biodiversity. To fully understand these new developments, however, students need a strong foundation in the study of species interactions and how these interactions are assembled into food webs and other ecological networks. This book, written for graduate students, advanced undergraduates, and practicing ecologists, presents a broad, up-to-date coverage of ecological concepts at an advanced level, including both the ‘new’ and ‘traditional’ aspects of community ecology. It is divided into five sections: 1) The Big Picture: Patterns, Causes, and Consequences of Biodiversity, 2) The Nitty-Gritty: Species Interactions in Simple Modules, 3) Putting the Pieces Together: Food Webs and Ecological Networks, 4) Spatial Ecology: Metapopulations and Metacommunities, and 5) Species in Changing Environments: Ecology and Evolution. Applied aspects of community ecology (e.g., resource harvesting, invasive species, community restoration) are treated throughout the book as natural extensions of basic theoretical and empirical work. Theoretical concepts are developed using simple equations and there is an emphasis on the graphical presentation of ideas. Each chapter includes a summary.
BRIEF TABLE OF CONTENTS 1 Community Ecology's Roots 1 PART I The Big Picture: Patterns, Causes and Consequences of Biodiversity 2 Patterns of Biological Diversity 13 3 Biodiversity and Ecosystem Functioning 41 PART II The Nitty-Gritty: Species Interactions in Simple Modules 4 Population Growth and Density-Dependence 65 5 The Fundamentals of Predator-Prey Interactions 83 6 Selective Predators and Responsive Prey 103 7 Interspecific Competition: Simple Theory 125 8 Competition in Nature: Empirical Patterns and Tests of Theory 149 9 Beneficial Interactions in Communities: Mutualism and Facilitation 175 PART III Putting the Pieces Together: Food Webs and Ecological Networks 10 Species Interactions in Ecological Networks 197 11 Food Chains and Food Webs: Controlling Factors and Cascading Effects 223 PART IV Spatial Ecology: Metapopulations and Metacommunities 12 Patchy Environments, Metapopulations, and Fugitive Species 251 13 Metacommunities and the Neutral Theory 267 PART V Species in Changing Environments: Ecology and Evolution 14 Species Coexistence in Variable Environments 289 15 Evolutionary Community Ecology 317 16 Some Concluding Remarks and a Look Ahead 339 |
| Last Updated on Friday, 13 April 2012 20:34 |
