NIMBioS Working Group: Ecology of Niche Variation
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| (Back row, L to R): Don DeAngelis, Sebastian Schreiber, Volker Rudolf, Mark Urban, Ben Van Allen, Reinhard Burger, Marcio Araujo, and Mark Novak; (Front row, L to R): Kelsey Jiang, Daniel Bolnick, Kevin McCann, and Gail Wolkowicz; (Not Pictured): Priyanga Amarasekare. |
The Value of Variation: Ecologists Consider Causes and Consequences
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| Photo Credit: Daniel Bolnick/Univ. of Texas, Austin |
Consider the case of the three-spine stickleback. These tiny fish that thrive in oceans and in fresh water might appear to be the same, yet ecologists are finding that they are actually a diverse collection of very specialized individuals.
Understanding the ecological causes and consequences of such ecological variation was the goal of a group of scientists who met at the National Institute for Mathematical and Biological Synthesis (NIMBioS) at the University of Tennessee, Knoxville, July 27-29.
Population and Community Ecology Consequences of Intraspecific Niche Variation was the topic of a NIMBioS Working Group comprised of biologists and mathematicians from universities and other academic institutions across North America and Europe.
Traditionally, ecological theory has treated a population as a homogeneous set of individuals, implicitly assuming that individuals within a population are ecologically interchangeable, but individuals are often quite diverse, said Daniel Bolnick, Working Group co-organizer and assistant professor of biology at the University of Texas, Austin.
"Very little is known about how niche variation affects the ecological dynamics of a species or a community, and yet it is important to understand it in order to make accurate predictions about a population," he said.
In order to make effective management decisions, for example, conservation biologists need to know under what conditions a predator and its prey can co-exist together. "The problem is that a lot of the ecological models say that predator/prey populations are unstable, and yet we know that they can co-exist. So, what we want to know is how does variation in a population change what we know about population dynamics," Bolnick said.
One of the unique aspects of the Working Group is its interdisciplinary approach involving both biologists and mathematicians to studying the issue.
"By establishing connections between these usually separate fields, we hope to initiate a new field of mathematical ecology that melds genetics, evolution, and dynamic foraging behavior into ecological models that will determine how intraspecific variation affects ecological dynamics and community structure," Bolnick said.
"At present, mathematical theory is our only tool to determine the ecological effects of niche variation and make recommendations for empiricists," Bolnick added.
NIMBioS Working Groups are comprised of 10-15 invited participants and focus on specific questions related to mathematical biology. Each group typically meets two to three times over the course of two years at the Institute.
The National Institute for Mathematical and Biological Synthesis (NIMBioS) brings together researchers from around the world to collaborate across disciplinary boundaries to investigate solutions to basic and applied problems in the life sciences. NIMBioS is funded by the National Science Foundation in collaboration with the U.S. Department of Homeland Security and the U.S. Department of Agriculture, with additional support from The University of Tennessee, Knoxville.
For more information, contact Catherine Crawley at 865-974-9350 or ccrawley@nimbios.org
NIMBioS Working Group: Ecology of Niche Variation
Topic: Population and community ecology consequences of intraspecific niche variation
Meeting dates: July 27-29, 2009; June 21-24, 2010
Organizers: Daniel Bolnick (Section of Integrative Biology, University of Texas at Austin); Volker Rudolf (Department of Ecology & Evolutionary Biology, Rice University) Kevin McCann (Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada)
Objectives: Ecologists have long treated the trophic niche as a property of a species as a whole, implicitly assuming that individuals within a population are ecologically interchangeable. A growing body of data suggests that apparently generalist populations are, in fact, often composed of ecologically heterogeneous and relatively specialized individuals (individual specialization). The evolutionary consequences of niche variation are increasingly well understood, permitting frequency-dependent competition that can drive disruptive selection and evolutionary diversification. In contrast, very little is known about how niche variation affects the ecological dynamics of species or communities. Can ecologists safely ignore intraspecific variation?
The goal of this working group is to use mathematical models to determine whether, and how, niche variation alters the dynamics of classical models of single-species, predator-prey, and community interactions. The impact of niche variation will depend on its mechanistic basis, which can arise from quantitative genetic variation for trophic morphology, culturally transmitted foraging behaviors, search image formation, or social structure. We will bring together biologists and mathematicians familiar with 1) empirical patterns of niche variation; 2) theoretical quantitative genetics, population genetics, foraging theory, and neural networks, which can reflect the mechanisms of niche variation; and 3) mathematical models of population, predator-prey, and food web dynamics. By establishing connections between these usually separate fields, we hope to initiate a new field of mathematical ecological that melds genetics, evolution, and dynamic foraging behavior into ecological models, to determine how intraspecific variation affects ecological dynamics and community structure. Empiricists have yet to develop methods to experimentally manipulate niche variation, so at present mathematical theory is our only tool to determine the ecological effects of niche variation and make recommendations for empiricists.
Meeting Summaries for the NIMBioS Working Group on Ecology of Niche Variation
Meeting 1 Summary, July 27-29, 2009
Participants: Priyanga Amarasekare (UCLA); Marcio Araujo (Florida International Univ.); Daniel Bolnick (Univ. of Texas); Reinhard Bürger (Univ. of Vienna); Donald DeAngelis (Univ. of Miami); Yuexin Jiang (Univ. of Texas, Austin); Yuan Lou (Ohio State Univ.); Kevin McCann (Univ. of Guelph); Mark Novak (Univ. of California, Santa Cruz); Volker Rudolf (Rice Univ.); Sebastian Schreiber (Univ. of California, Davis); Richard Svanback (Univ. of Uppsala); Mark Urban (Univ. of Connecticut); Ben Van Allen (Rice Univ.); Gail Wolkowicz (McMaster Univ.)
During the first meeting, the "niche variation" working group settled on a focal question that would bind together our various sub-projects: how do the dynamics familiar ecological models change when one incorporates realistic patterns of intraspecific variation? The group assembled a list of relevant models that have been published previously and devised a strategy to split up the work of reviewing this prior literature. The group plans to write two review papers, one summarizing the relevant theoretical literature, and the second summarizing recent empirical progress in understanding the basis for why some populations exhibit more niche variation than others. Sub-groups then formulated specific models that incorporate niche variation into familiar ecological interactions, such as apparent competition, pollinator-plant dynamics, or tritrophic food chains. The group plans to analyze the dynamics of these models to determine how they behave with versus without intraspecific niche variation.
Meeting 2 Summary, July 21-24, 2010
Participants: Priyanga Amarasekare (Dept. of Ecology and Evolutionary Biology, UCLA); Marcio Araujo (Dept. of Biological Sciences, Florida International University); Daniel Bolnick (School of Biological Sciences, University of Texas, Austin); Reinhard Bürger (Dept. of Mathematics, University of Vienna); Donald DeAngelis (Dept. of Biology, University of Miami); Yuexin Jiang (School of Biological Sciences, University of Texas, Austin); Jonathan Levine (Dept. of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara); Yuan Lou (Dept. of Mathematics, Ohio State University, Columbus); Mark Novak (Dept. of Ecology and Evolutionary Biology, University of California, Santa Cruz); Volker Rudolf (Dept. of Ecology and Evolutionary Biology, Rice University); Sebastian Schreiber (Dept. of Evolution and Ecology, University of California, Davis); Richard Svanbäck (Dept. of Ecology and Evolution, Uppsala University); Mark Urban (Dept. of Ecology and Evolutionary Biology, University of Connecticut); David Vasseur (Dept. of Ecology and Evolutionary Biology, Yale University); Gail Wolkowicz (Dept. of Mathematics, McMaster University)
This second meeting began with a review of the group's goals (to investigate how within-population trait variation alters the outcome of familiar ecological models). The remainder of the first day was spent on presentations of work in progress, including outlines of two review papers that are in preparation, and three models. The second day of the working group involved work by break-out groups focused on exploring specific models of (1) evolution of migration rates (now submitted for review), (2) quantitative genetic variance in apparent competition (close to submission), (3) size variance within species in food webs, (4) variance and interspecific competition, and (5) effects of diet variation on food chain coupling. The third day was split between a field trip to the Smoky Mountain National Park, and a large group discussion revising the outline of the main review paper (now being written for Trends in Ecology and Evolution). The final day was focused on making progress on individual and sub-group projects in break-out groups, including an extensive discussion of food web models. Between this meeting and our final (February 2011) meeting, the plan is to submit the two review papers and manuscripts on at least three of the model projects. One meeting participant is also spearheading an application for a symposium at the 2011 Ecological Society of America meeting.
NIMBioS Working Groups are chosen to focus on major scientific questions at the interface between biology and mathematics. NIMBioS is particularly interested in questions that integrate diverse fields, require synthesis at multiple scales, and/or make use of or require development of new mathematical/computational approaches. NIMBioS Working Groups are relatively small (10-12 participants, with a maximum of 15), focus on a well-defined topic, and have well-defined goals and metrics of success. Working Groups will typically meet 2-4 times over a two-year period, with each meeting lasting 3-5 days; however, the number of participants, number of meetings, and duration of each meeting is flexible, depending on the needs and goals of the Group.
