Woodland and Wetland Restoration
Great Lakes coastal wetlands provide critical natural habitat, invaluable ecological functions, and myriad benefits to humans. Unfortunately, many of these ecosystems are being negatively impacted by aggressive invasive cattails, resulting in reduced species diversity and altered ecological function. Managing these invasive species is a perpetual and expensive challenge which commonly results in negative unintended consequences. Typically management techniques include herbiciding, which introduces toxic chemicals, or burning, which emits greenhouse gases and particulate pollution.
In partnership with Dr. Dennis Albert of Oregon State University, we are researching sustainable Typha management strategies designed to avoid the unintended consequences or current restoration practice while improving biodiversity recovery, reducing restoration costs, and simultaneously creating carbon-neutral renewable energy. This project, A Sustainable Approach for Restoring Wetland Biodiversity, is funded through a three-year Environmental Protection Agency, Great Lakes Restoration Initiative grant.
The goals of our research are to conduct experimental ecological restoration in which we are mechanically harvesting cattail biomass from invaded wetlands, monitoring the effects of harvesting on wetland biodiversity and utilizing harvested cattail biomass to produce renewable and carbon-neutral biogas. Additionally, we are modeling the efficacy of producing renewable energy with invasive species biomass and conducting an economic analysis of the costs and benefits of harvesting cattail biomass for anaerobic digestion as compared with burning and herbiciding. In summer 2011 we implemented the restoration activities in four Great Lakes coastal wetlands in Michigan.
We determined the extent and dominance of cattail species, the current composition and diversity of the plant communities, and the above- and below ground plant and leaf-litter biomass in our study wetlands. These data will be compared with post-restoration data to determine the effectiveness of our restoration techniques. Also, biomass measurements will be used to model the renewable energy production potential of each site.
Renewable Energy Potential
Our preliminary results illustrate the great potential that invasive cattail biomass may have for the production of renewable energy. Cattail makes up 92% of the total plant biomass in our study wetlands, making up an average of 38 metric tons / ha of biomass. Assuming efficient conversion to biogas, utilization of the cattails from our study wetlands would result in the production of 411,000 m3 of biogas; which if produced in a combined heat and power biogas facility, could provide enough electricity to power 96 homes and enough warmth to heat 235 homes for a year, preventing the emission of 893 metric tons of CO2.
Over the next two years, we will determine the renewable biogas production potential of three of the most troublesome invasive plant species in the Great Lakes region, cattails, common reed, and Eurasian water milfoil. We will determine the effects of restoration activities on plant and invertebrate communities and we will determine the economic feasibility of mechanical-harvesting restoration of cattail invaded Great Lakes coastal wetland ecosystems.
We hope that the results of this study will compel managers to implement truly sustainable restoration solutions to degraded coastal wetlands.
For more information, see the current Great Lakes Fish and Wildlife Restoration Act pre-proposal.