Joy B. Zedler
Professor of Botany and Aldo Leopold Chair in Restoration Ecology
Ph.D. (1968) University of Wisconsin
302 Birge Hall
Restoring ecosystems to functional equivalency with reference systems requires that the site support essential functions, attract the desired species, and resist invasion by unwanted species (e.g., exotics). Both physical and biological variables affect the ability of a restoration site to achieve these goals. For most ecosystems, we know far too little about what constrains restoration; hence, the opportunities for research are numerous, and the demand for information is great.
Research at UW focuses on the development of methods to improve the design, implementation, and assessment of habitat restoration projects. Much of our work concerns sedge meadows and how hydrological disturbances shift native vegetation toward reed canary grass (Phalaris arundinacea) and hybrid cattails (Typha x glauca). Our aim is to understand these invasions and find ways to restore native biodiversity. We have made considerable progress in explaining the conditions that promote invasions; we continue to explore replacement assemblages of native plants that can thrive in hydrologically-modified wetlands and resist reinvasion in the long term. Students test hypotheses under field, mesocosm, and greenhouse conditions. Results are interpreted in light of ecological theory and management applications.
Studies in southern California emphasize (1) the effects of topographic heterogeneity on salt marsh structure and functioning, particularly the importance of tidal creek networks to vegetation and marsh food webs (2) the effects of biotic diversity on ecosystem function. We have shown that species-rich assemblages retain more nitrogen, support more complex canopies, and resist invasions. We are now exploring complementary and facilitative interactions among salt marsh species to understand better how diverse assemblages persist.
Comparing the degradation of sedge meadows with that in salt marshes is another fruitful area of inquiry. In both wetland types, hydrological disturbances lead to reduced species richness and a tendency toward monotypic vegetation. In both cases, the disturbances tend to homogenize sites. Providing heterogeneity (both spatial and temporal variability in environmental factors) in the restoration sites might well be a key to restoring diversity.
As the Aldo Leopold Professor of Restoration Ecology, I facilitate research at the University of Wisconsin Arboretum and encourage students and others to study the Arboretum's collection of restored and restorable communities. My students address issues of importance to the restoration of wetlands within the Arboretum, within the state of Wisconsin, within the Upper Midwest region, and beyond. For example, they conduct experiments in stormwater basins in the Chicago area and explore changes in lakeshore wetlands along Lake Michigan, while testing theory about community structure and ecosystem functioning. Experiments done in outdoor mesocosms at the Arboretum are helping to explain why reed canary grass and cattails are increasingly dominant in both stormwater wetlands and lakeshore wetlands. In addition, our analysis of how ecosystem functions change with compositional shifts helps us and wetland managers understand the consequences of invasions.
The science of restoration ecology is advanced when ideas are tested rigorously in many contexts. Toward that aim, an exchange program between Mexico, the United States and Canada allows students to study restoration in a foreign country and at their home institution (UNAM and U. Guadalajara-CUCSUR in Mexico, UW and Louisiana State U. in the US, and Guelph U. and McGill U. in Canada). Our ideas about how to restore marshes in Wisconsin are already benefiting from new research on how to restore riparian forest along Mexico's Ayuquila River.
The practice of ecological restoration is advanced when we improve our ability to predict the utility of alternative restoration approaches and when new techniques prove useful in multiple settings. We recommend adaptive restoration approaches to advance the science and practice simultaneously, by designing restoration sites as large-scale field experiments that can test alternative approaches and demonstrate which are most effective and why.
Students work on the above issues through many programs and with many collaborators across the UW campus. M.S. and Ph.D. programs are offered by the Botany Department, the Gaylord Nelson Institute for Environmental Studies, and the Limnology and Marine Science program.
Sally Gallagher (M.S. 2009) Botany Department
Michael Healy (M.S. 2009) NIES, Environment & Resources
Steven Hall (M.S. 2008) NIES, Land Resources
Cathi Bonin (M.S.2007) Botany Department
Nic Jelinski (M.S. 2007) Land Resources, NIES
Alison Varty (M.S. 2007), Botany Department
Aaron Boers (Ph.D. 2006) Botany Department
Dan Larkin (Ph.D. 2006) Botany Department
Christin Frieswyk (Ph.D. 2005) Botany Department
Andrea Herr-Turoff (Ph.D.2005) Botany Department
Hem Nalini Morzaria-Luna (Ph.D. 2004) Botany Department
Anastasia Allen (M.S.2004) NIES, Conservation and Sustainable Development
Michelle Peach (M.S. 2004) Land Resources (Institute for Environmental Studies)
Julia Wilcox (M.S. 2004) Land Resources, (Institute for Environmental Studies)
Erin O'Brien (M.S. 2003) NIES, Land Resources
Suzanne Kercher, (Ph.D.2003), Botany Department
Rachel Veltman (M.S. 2002) Land Resources (Institute for Environmental Studies)
Roberto Lindig-Cisneros (Ph.D. 2001) NIES, Land Resources
Debbie Maurer (M.S. 2001) Botany Department
Katy "Werner" Wallace (M.S. 2001) Land Resources (Institute for Environmental Studies)
Isa Woo (M.S. 2000) Botany Department
Cristina Bonilla-Warford (M.S. 2000) NIES, Conservation Biology and Sustainable Development
Becky Miller (M. S.) NIES, Conservation Biology and Sustainable Development
Tara Roeffler (M.S.) NIES, Water Resources Management
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