Research at the Arboretum
UW Madison PhD student Beth Lawrence describes how water levels and nutrients affect tussock formation in a native wetland plant (tussock sedge). This experiment and three others undeway at the Arboretum's Mesocosm Facility were featured at the June 18 Open House.
Adaptive Restoration
In accordance with the UW Arboretum mission statement, our research program aims to advance restoration ecology and improve the practice of ecological restoration. From among a large and continually-expanding array of possibilities, our focus is on Arboretum lands, and our theme is "adaptive restoration" (learning while restoring). Using this approach, we identify land-care problems, clarify what needs to be known to solve them, design field experiments to test alternative restoration methods, and use the resulting knowledge in future efforts. Over time, these efforts have grown to integrate land care, research and education, as in the adaptive restoration of Lower Greene Prairie.
Adaptive restoration fulfills all three components of the Arboretum mission: restoring and conserving Arboretum land, advancing restoration ecology, and fostering the land ethic through education.
At Lower Greene Prairie, the land-care problem is excessive stormwater inflows that facilitate reed canary grass. This invasive grass now forms a monotype over nearly 10 acres of Henry Greene's carefully planted prairie (see graphic at the top of this page). The first experiment tested our ability to replace reed canary grass with native plants. This study, by graduate student Julia Wilcox, found high establishment in year 1, but rapid regrowth of the invader in year 2. Institute for Environmental Studies PhD student Mike Healy then experimented with control using a grass-specific herbidicide, which reversed dominance (see their paper in Natural Areas Journal, October 2007). Because the grass-specific herbicide cannot be used under aquatic conditions, our ability to continue treatments is constrained by weather. Thus, we shifted our focus to the outer edge of the monotype, where inundation is less frequent.
This year (2007), students of the General Ecology course are following the footsteps of the land care restorationist, Mike Hansen, who herbicided a 3-m wide band of reed canary grass along the edge of the monotype. In mid-September, some 90 students began a long-term experiment in seeding native plants and assessing their reestablishment. Botany Senior Scientist Dr. Suzy Will-Wolf, who organizes the lab exercises, plans to continue seeding and assessing for up to five years in an attempt to expand wet prairie vegetation while reducing the footprint of stormwater inflows.
In early field studies, graduate students Katy Werner, Debbie Maurer, and Rebecca Miller showed that reed canary grass was facilitated by sedimentation, nutrient influxes, and altered hydrological conditions. Their findings led to a series of controlled experiments in large tanks (mesocosms) where each factor was varied alone and in combination (3x3x3=27 treatments). This experiment helped two students (now Dr. Suzanne Kercher and Dr. Andrea Herr-Turoff) understand why reed canary grass grows so well in stormwater-runoff. The excess water and nutrients (sometimes brought in along with sediments) interact synergistically to enhance reed canary grass growth and formation of monotypes. See their forthcoming article in Biological Invasions.
Curtis Prairie also has its reed canary grass invasion. Land Resources student Mike Healy capitalized on that problem to test the ability of a grass-specific herbicide (sethoxydim) to control the invasion. Mike has also tested the need to re-seed native species, experimenting with a suite of species that does not include grasses, in order to continue sethoxidim applications over three years time. His long-term experiments support the need to deal with this aggressive invader with long-term managementplans.
Invasive cattails are the scourge of Gardner Marsh, where graduate student Isa Woo began reseaching causal mechanisms in 1999. Her work, published in Wetlands, demonstrated that nutrient additions alone could catalyze the expansion of a cattail monotype into a dwindling sedge meadow community.
Dr. Frank Scarpace, a University of Wisconsin professor and expert in remote sensing, offered students in the Environmental Studies capstone course the opportunity to track expansion of two invaders, cattails and buckthorn. Their findings suggested that cattails were expanding at a rate of 80 cm/year into the remnant sedge meadows. This finding prompted Steven Hall (Land Resources MS student) to undertake a cattail-control experiment in Gardner Marsh. Herbiciding and cutting were compared, with the most effective method requiring four cuttings per year to reduce starch reserves in this invader's robust rhizome system. Watch for his Master's thesis in 2008.
The overall stormwater impacts in Gardner and Southeast Marshes led Arboretum Research Director and Leopold Professor of Restoration Ecology Joy Zedler to organize a Water Resources Management Practicum for the eastern Arboretum Wetlands. The eight students who explored opportunities for reducing stormwater into Southeast Marsh mapped vegetation in both marshes, tracked water flow pattenrs, and followed the quality of water coming into and out of the wetlands will publish a report in fall, 2007.
As a student, Dr. Roberto Lindig-Cisneros (now professor at Universidad Nacional Autonoma Mexico-Morelia) showed that light is a key factor for reed canary grass seeds to germinate and for plants to establish in wetland plant canopies. Using mesocosms, he cut 10x10-cm openings, which were large enough to provide light for seed germination. In the field, he cut reed canary grass sod and reestablished native species in a project that generated a 5-year class experiment for the General Ecology class. Each year, the students cleared small plots of reed canary grass sod and added native plant seeds. Reed canary grass was partly subdued and partly facilitated by the sod removal, however, leaving the site still dominated by the invasive grass.
While stormwater effects on native vegetation are a key interests, the effects of native vegetation on stormwater has equal research value. In summer 2007, Josh Brown (Water Resources Management student and Arboretum Project Assistant) grew 40 species of native plants in order to predict how each might perform in stormwater facilities. Some will likely excel at stabilizing soil (as in the stormwater conveyance channel that will be constructed in winter 2007-08 upstream of Secret Pond). Assessing plant growth is hard work, so the Adaptive Restoration Lab students will help Josh measure height, branching, and biomass of roots and shoots in fall 2007.
In each of these cases, land care, research and education are being integrated to facilitate learning while restoring -- adaptive restoration.
Go to a document with additional information on the adaptive restoration approach at the UW-Madison Arboretum.
If you have a question about research at the Arboretum, please send us a message through our online contact form and we will direct it to the appropriate staff member.