Harvesting invasive Typha biomass: an innovative approach to coastal wetland restoration

Session: Great Lakes Coastal Wetlands: Innovative Research to Improve Restoration (3)

Beth Lawrence, University of Connecticut; Dept. of Natural Resources & Environment, [email protected]
Shane Lishawa, Loyola University Chicago- Institute for Environmental Sustainabilit, [email protected]
Dennis Albert, Oregon State University, [email protected]
Nancy Tuchman, Loyola University Chicago, [email protected]

Abstract

Typha x glauca is a problematic wetland invader dominating >28,000 ha of coastal wetlands throughout the Great Lakes. Typha is a primary target for management actions in the region as its invasion reduces native plant diversity and homogenizes wildlife habitat. Traditional restoration approaches (herbiciding, burning) have largely been ineffective because they do not address nutrient enrichment, one of the primary causes of invasion. With support from the Great Lakes Restoration Initiative (2011-present), we have been testing experimental Typha harvest (i.e., cutting and removing above-ground biomass) in northern Michigan at a variety to scales (4m² mesocosms to 3600m² field plots) and spatial configurations to quantify how this innovative restoration technique affects a range of wetland responses. Typha harvest increases plant diversity, produces a viable potential bioenergy source, and removes nutrients stored in plant tissues.  However, relative to Typha-dominated controls, harvesting can increase porewater nutrient availability (by reducing plant demand), and increase wetland methane emissions.  Together, our data highlight the importance of quantifying a range of responses during wetland restoration so that managers can evaluate potential trade-offs when considering alternative management objectives.