Dan is a postdoctoral fellow in the
Department of Biology and Center for Urban Environmental Research and Policy at Loyola University Chicago

Educational Background:

2002- present: PhD Candidate, Department of Botany, University of Wisconsin-Madison. Anticipated graduation date: May 2006

B.A. in Biology, University of California, Santa Cruz, 1998

Ecological theory suggests that key ecosystem functions can be enhanced by incorporating environmental heterogeneity into restoration design. We are testing this experimentally by examining food web responses to topographic heterogeneity in a salt marsh restoration site in Tijuana Estuary (San Diego, CA). Topographic heterogeneity in the form of tidal creek networks is an experimental treatment in the 8-ha Model Marsh, where three replicate "cells" (@1.3-ha) contain tidal creeks and three do not. At a smaller scale, heterogeneity comes from pools and mounds that have naturally formed since the site was opened to tidal flushing in 2000. By studying how these types of heterogeneity influence algal and invertebrate composition and abundance and fish use of the marsh and feeding, we are hoping to develop strategies to make restoration efforts more effective in food web support.

To further understand the factors that regulate trophic functioning in this system, we have been conducting experiments to test the degree of bottom-up vs. top-down control of trophic modules in tidal pools and how these factors vary seasonally. We performed four experiments in March-October 2005 in which we manipulated bottom-up inputs through presence or absence of nitrogen fertilization and top-down control by allowing or excluding fish. We hypothesize that evidence of top-down control by fish will be virtually absent in spring and early summer and increase in late summer and fall due to the strong seasonality in tidal regimes and use of the marsh by Fundulus parvipinnis (California killifish).

Publications

Larkin, D. J., and J. B. Zedler. In prep. Trophic functioning of ephemeral salt marsh pools.  Ph.D. Dissertation, University of Wisconsin-Madison and submission to Ecological Applications.

Larkin, D. J., and J. B. Zedler. In prep. Spatial and temporal heterogeneity influence fish use of a restored tidal marsh. Ph.D. Dissertation, UW-Madison and submission to Estuaries.

Larkin, D.J., and J.B. Zedler. In review. (invited chapter) Coon Valley and Tijuana Estuary: Lessons for restoration. In J. Sage and M. Nelson, eds. AFS Leopold Legacy. American Fisheries Society, Bethesda, MD.

Larkin, D. J., G. Vivian-Smith, and J. B. Zedler. In press. (invited chapter) Topographic heterogeneity theory and ecological restoration. In D. A. Falk, M. A. Palmer, and J. B. Zedler, eds. Foundations of Restoration Ecology. Island Press, Washington, D.C.

Allen, A., S. Kercher, D. Larkin, H. Morzaria-Luna, and M. Peach. 2003. Review of book by Perrow, M. R., and A. J. Davy, eds. 2002. Handbook of ecological restoration. Volume 1: Principles of restoration. Volume 2: Restoration in practice. Cambridge University Press, Cambridge, UK. Conservation Ecology 7(2):4. URL: http://www.consecol.org/vol7/iss2/art4

Larkin, D. J., and R. S. Tjeerdema. 2000. Fate and effects of Diazinon. Reviews of Environmental Contamination and Toxicology 166:49-82.

Conference Presentations

Larkin, D. J., and J. B. Zedler. Food web effects of topographic heterogeneity. Invited symposium presentation at the 91st Annual Meeting of the Ecological Society of America. Memphis, TN. Aug. 6-11, 2006.

Larkin, D. J., and J. B. Zedler. Abstract accepted. Topographic heterogeneity: A tool for restoring trophic function in wetlands. Oral presentation at the 11th Annual Wisconsin Wetlands Association Science Forum. Madison, WI. Feb. 2-3, 2006.

Zedler, J. B., J. C. Callaway, S. P. Madon, K. J. Wallace, D. J. Larkin, E. L. O'Brien, and A. Varty. 2005. The effect of tidal creeks on salt marsh functioning. Poster presentation at the 18th Biennial Conference of the Estuarine Research Federation. Norfolk, VA. Oct. 16-21, 2005.

Larkin, D. J., J. B. Zedler, S. P. Madon, and J. M. West. 2004. Multiple forms of heterogeneity enhance fish use of a restored tidal marsh. Poster presentation at the 2nd Biennial Restore America’s Estuaries Conference. Seattle, WA. Sept. 12-15, 2004.

Research Photos

Last updated: December 7, 2005

Feedback, questions or accessibility issues: hboehm@wisc.edu

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