Research Interests

My general areas of research are community ecology and population biology, although my work also extends into evolution and behavior. I do both theoretical and empirical work, and often try hard to combine them directly. My main projects include:

Multispecies interactions and environmental fluctuations
Population dynamics of insect predator-prey systems
Phylogenetic patterns in comparisons among species and communities
Theory, statistics, and complex population dynamics


Multispecies interactions and environmental fluctuations

How do interactions among species within an ecological community influence the response of the community to environmental perturbations? This is a central question in understanding how community structure affects the resistance and resilience of ecosystems. I am particularly interested in the application of stochastic models to multispecies data sets, using patterns of population fluctuations to explore the consequences of species interactions for the general dynamical properties of the system.



Selected publications
Lab members:

P = UW Postdoctoral researcher
G = UW Graduate student
U = UW Undergraduate
H = High School student

• Ives, A. R., B. Dennis, K. L. Cottingham, and S. R. Carpenter. 2003.  Estimating community stability and ecological interactions from time-series data.  Ecological Monographs 73: 301-330.

• Kilpatrick, A. M., and A. R. Ives. 2003.  Species interactions can explain Taylor’s power law for time series.  Nature 422: 65-68.

• Beisner, B. E.^P, A. R. Ives, and S. R. Carpenter. 2003.  The effects of an exotic fish invasion on the prey communities of two lakes.  Journal of Animal Ecology 72: 331-342.

• Ripa, J.^P, and A. R. Ives. 2003.  Food web dynamics in correlated and autocorrelated environments.  Theoretical Population Ecology 64: 369-384.

• Ives, A. R., and B. J. Cardinale^P. 2004.  Food-web interactions govern the resistance of communities following non-random extinctions.  Nature 429: 174-177.

• Ives, A. R., B. J. Cardinale^P, and W. E. Snyder. 2005.  A synthesis of subdisciplines: predator-prey interactions, and biodiversity and ecosystem functioning.  Ecology Letters 8: 102-116.

• Ives, A. R. 2005.  Community diversity and stability: changing perspectives and changing definitions.  Pages  in K. Cuddington and B. E. Beisner, editors.  Ecological Paradigms Lost: Routes to Theory Change. Academic Press.

• Lehmann-Ziebarth, N.^U, and A. R. Ives. 2006. The structure and stability of model ecosystems assembled in a variable environment. Oikos 114:451-464.

• Weis, J. J.^U, B. J. Cardinale^P, K. J. Forshay, and A. R. Ives. 2007. Effects of species diversity on the production of community biomass change in form and magnitude over the course of succession. Ecology 88:929-939.

• Ives, A. R., and S. R. Carpenter. 2007. Stability and diversity of ecosystems. Science 317:58-62.


Population dynamics of insect predator-prey systems

Pea aphids in Wisconsin alfalfa fields rarely reach densities sufficient to cause crop damage due to high levels of predation and parasitism. How do predators and parasitoids act to suppress aphid populations in a persistent, stable fashion? To address this problem, I employ experiments both in the lab and in the field, and integrate the results of the experiments using a variety of theoretical tools. I am currently working with Nancy Moran (University of Arizona) who can produce aphid clones that differ in heat tolerance. Using these clones, I am investigating the possible effects of climate change on pea aphid pest densities.



Selected publications
Lab members:

P = UW Postdoctoral researcher
G = UW Graduate student
U = UW Undergraduate
H = High School student

• Snyder, W. E.^P, and A. R. Ives. 2003.  Interactions between specialist and generalist natural enemies: parasitoids, predators, and pea aphid biological control.  Ecology 84: 91-107.

• Östman, Ö., and A. R. Ives. 2003.  Scale-dependent indirect interactions between two prey species through a shared predator.  Oikos 102: 505-514.

• Cardinale, B. J.^P, C. T. Harvey^G, K. Gross^G, and A. R. Ives. 2003.  Biodiversity and biocontrol: Emergent impacts of a multi-enemy assemblage on pest suppression and crop yield in an agroecosystem.  Ecology Letters 6: 857-865.

• Lin, L. A.^H, and A. R. Ives. 2003.  The effect of parasitoid host-size preference on host population growth rates: an example of Aphidius colemani and Aphis glycines.  Ecological Entomology 28: 542-550.

• Demmon, A. S.^U, H. J. Nelson^U, P. J. Ryan^U, A. R. Ives, and W. E. Snyder. 2004.  Aphidius ervi (Hymenoptera : Braconidae) increases its adult size by disrupting host wing development.  Environmental Entomology 33: 1523-1527.

• Aquilino, K. M.^U, B. J. Cardinale^P, and A. R. Ives. 2005.  Reciprocal effects of host-plant and natural enemy diversity on herbivore suppression: An empirical study of a model tri-trophic system.  Oikos 108: 275-282.

• Gross, K.^G, A. R. Ives, and E. V. Nordheim. 2005. Estimating time-varying vital rates from observation time series: a case study in aphid biological control. Ecology 86:740-752.

• Langley, S. A.^U, K. J. Tilmon^P, B. J. Cardinale^P, and A. R. Ives. 2006. Learning by the parasitoid wasp, Aphidius ervi (Hymenoptera: Braconidae) alters individual fixed preferences for pea aphid color morphs. Oecologia 150:172-179.

• Meisner, M.^H, J. P. Harmon^P, and A. R. Ives. 2007. Presence of an unsuitable host diminishes the competitive superiority of an insect parasitoid: a distraction effect. Population Ecology 49.

Phylogenetic patterns in comparisons among species and communities

Evolutionarily related species are likely to share many of the same traits due to their phylogenetic descent from a common ancestor. With Ted Garland (UC-Riverside) as a frequent collaborator, I develop statistical methods to investigate phylogenetic correlations of traits among species. Because the occurrence and abundance of species in ecological communities depend on their traits, community composition is also likely to show phylogenetic patterns with, for example, phylogenetically related species more likely to occur in the same communities. Thus, I am extending methods derived for comparisons of traits among species to compare the compositions of different ecological communities.



Selected publications
Lab members:

P = UW Postdoctoral researcher
G = UW Graduate student
U = UW Undergraduate
H = High School student

• Garland, T., and A. R. Ives. 2000.  Using the past to predict the present: confidence intervals for regression equations in phylogenetic comparative methods.  American Naturalist 155: 346-364.

• Blomberg, S. P., T. Garland, and A. R. Ives. 2003.  Testing for phylogenetic signal in comparative data: behavioral traits are more labile.  Evolution 57: 171-745.

• Ives, A. R., and H. C. J. Godfray. 2006. Phylogenetic analysis of trophic associations. American Naturalist 168:E1-E14.

• Huey, R. B., B. Moreteau, J. C. Moreteau, P. Gibert, G. W. Gilchrist, A. R. Ives, T. Garland Jr., and J. R. David. 2006. Evolution of sexual size dimorphism in a Drosophila clade, the D. obscura group. Zoology 109:497-505.

• Helmus, M. R.^G, T. J. Bland^U, C. K. Williams^P, and A. R. Ives. 2007. Phylogenetic measures of biodiversity. American Naturalist 169:E68-E83.

• Helmus, M. R.^G, K. Savage^U, M. W. Diebel, J. T. Maxted, and A. R. Ives. 2007. Separating the determinants of phylogenetic community structure. Ecology Letters 10:917-925

• Ives, A. R., P. E. Midford, and T. Garland Jr. 2007. Within-species variation and measurement error in phylogenetic comparative methods. Systematic Biology 56:252-270.

Theory, statistics, and complex population dynamics

Selected publications
Lab members:

P = UW Postdoctoral researcher
G = UW Graduate student
U = UW Undergraduate
H = High School student

• Williams, C. K.^P, A. R. Ives, and R. D. Applegate. 2003.  Population dynamics across geographical ranges: time-series analyses of three small game species.  Ecology 84: 2654-2667.

• Ives, A. R., S. T. Woody, E. V. Nordheim, C. Nelson, and J. H. Andrews. 2004.  The synergistic effects of stochasticity and dispersal on population densities.  American Naturalist 163: 375-387.

• Williams, C. K.^P, A. R. Ives, R. D. Applegate, and J. Ripa^P. 2004.  The collapse of cycles in the dynamics of North American grouse populations.  Ecology Letters 7: 1135-1142.

• Woody, S. T., A. R. Ives, E. V. Nordheim, and J. H. Andrews. 2007. Dispersal, density dependence, and population dynamics of a fungal microbe on leaf surfaces. Ecology 88:1513-1524.

• Solbreck, C., and A. R. Ives. 2007. Density dependence vs. independence, and irregular population dynamics of a swallow-wort fruit fly. Ecology 88:1466-1475.

• Forester, J. D., A. R. Ives, M. G. Turner, D. P. Anderson, D. Fortin, H. L. Beyer, D. W. Smith, and M. S. Boyce. 2007. State-space models link elk movement patterns to landscape characteristics in Yellowstone National Park. Ecological Monographs 77:285-299.

• Ives, A. R., A. Einarsson, V. A. A. Jansen, and A. Gardarsson. 2008. High-amplitude fluctuations and alternative dynamical states of midges in Lake Myvatn. Nature in press.
  

Courses:

Zoology 260 - Introductory Ecology
Zoology 540 - Theoretical Ecology
Zoology 956 - Seminar - Ecology: Professional Development

Note to prospective graduate students:

I am particularly interested in attracting graduate students who want to combine empirical and theoretical approaches to ecological studies. My lab is diverse, with students having worked on malaria in lizards, biological control of pea aphids, the dynamics of freshwater phytoplankton, fish community composition, and other topics. A broad background and interest in collaborating on a wide range of ecological questions is essential.

When I was applying for graduate school, the most important thing I looked for was a place where I had the flexibility and resources to do my own research. Now as a faculty advisor, I encourage students to develop their own projects and interests. There are limits, however, as I don’t want to take on students who are so far a field that I can’t give adequate advice and support. But the mix of people in the lab provides a rich collective knowledge that can help with a variety of projects. I actively encourage collaborations within the lab, and between lab members and others on campus. To select prospective graduate students to fit in with the collaborative atmosphere of the lab, the entire lab has a strong say in accepting graduate students.

Graduate students currently supervised:

Kate Forbes (aeforbes@students.wisc.edu)
Kate started in fall, 2001. As an undergraduate, she did a study on the metapopulation and meta-community dynamics of zooplankton. Her Ph.D. investigates the source-sink dynamics of natural enemies of agricultural pests in the mosaic of agricultural fields.

Matt Helmus (mrhelmus@wisc.edu)
The main focus of Matt’s Ph.D. is identifying phylogenetic patterns in the composition of ecological communities. He has conducted field work on benthic invertebrates and fish communities in central Mexico.

Tucker Gilman (rgilman@wisc.edu)
Tucker started in my lab in fall, 2004, and is currently working on two theoretical projects for his Ph.D. The first investigates the collapse of the genetic distinction between species through hybridization, and the second asks whether genetic variation in dispersal behavior can be maintained in a seasonal environment.

Jocelyn Behm (jebehm@wisc.edu)
In 2006, Jocelyn joined the first cohort of an NSF-IGERT training program for Ph.D. research in Yunnan, China. She is studying the distribution and genetics of amphibian populations to understand how they are affected by human land-use change and environmental disturbances.

Nicole Rafferty (nrafferty@wisc.edu)
Nicole joined my lab in 2007 after completing her M.A. degree at the UW-Madison studying the behavioral evolution of stickleback fish. Her Ph.D. work addresses the impact of climate change on plant-pollinator interactions.

Jacob Usinowicz (usinowicz@wisc.edu)
Jacob has a background in mathematics and physics, and he joined the lab in 2008. He plans to apply a variety of mathematical methods that incorporate space and individual variation in fitness to investigate coexistence in diverse plant communities.

Students supervised who've recently earned graduate degrees:

Johannes Foufopoulos, Ph.D. – 1998 (Assistant Professor at U Michigan)
    Host-parasite interactions in the Mountain Spiny Lizard Sceloporus jarrovi. Abstract

Kevin Gross, Ph.D. – 2003 (Assistant Professor at NC State)
    The aphid, the wasp, and the matrix: aspects of modeling host-parasitoid and single-species dynamics. Abstract

Chad Harvey, Ph.D. – 2007 (Postdoc at University of Windsor)
    How variation in the composition of insect food-webs affects the strength and outcome of both direct and indirect interactions among the constituent species

Eric Klopfer, Ph.D. – 1997 (Associate Professor at MIT)
    Ecological and evolutionary consequences of explicit spatial structure in exploiter-victim systems. Abstract

Jennifer Lynn Klug, Ph.D. – 2000 (Associate Professor at Fairfield University)
    Complex effects of colored dissolved organic matter on algal growth and community composition. Abstract

Todd Palmer, M.A. – 1994 (Assistant Professor at U Florida)
    The influence of spatial heterogeneity on the behavior and growth of two herbivorous stream insects

Current postdocs

Karen Abbott (kcabbott@wisc.edu)
    Theoretical ecology; spatio-temporal population fluctuations

Jason Harmon (jharmon@wisc.edu)
    Predator-prey interactions; climate effects on pest control

Former postdocs

Bea Beisner 2000-2002 with Steve Carpenter (Assistant Professor at Université du Québec à Montréal)

Brad Cardinale 2002-2005 (Assistant Professor at UC-Santa Barbara)

Meghan Duffy 2006-2007 (Assistant Professor at Georgia Tech)

Ralph Haygood 2002-2005 (Research Associate at Duke University)

Derek Johnson 2005 (Assistant Professor at U Louisiana)

John Losey 1996-97 (Associate Professor at Cornell University)

Jörgen Ripa 2000-2001 (Assistant Professor at Lund University)

Nancy Schellhorn 1998-99 (research scientist for CSIRO, Australia)

Bill Snyder 1999-2000 (Associate Professor at Washington State University)

Kelley Tilmon 2002-2005 (Assistant Professor at University of South Dakota)

Chris Williams 2001-2004 (Assistant Professor at University of Delaware)