Great Lakes Coastal Wetland Communities: Vulnerabilities to Climate Change and Adaptation StrategiesBy:
March 28, 2013
Coastal wetlands in the Great Lakes region will be impacted by climate change. Namely, changes in water level could have dire consequences for existing wetlands and dependent bird and fish communities. To examine the impacts climate change may cause to coastal wetlands, project staff assessed vulnerabilities and evaluated adaptation options.
In 2002, the Department of Natural Resources Canada held an open call for proposals for the Climate Change Action Fund – Coastal Zone. Partners from the University of Waterloo, Canadian Wildlife Service, Environment Canada, and local, private environmental firms submitted a proposal to produce a report explaining the vulnerability of Great Lakes coastal wetland ecosystems to climate change and identifying and developing related management and policy adaptation strategies. Their objectives were to use GIS to analyze shoreline vulnerabilities of the Great Lakes, develop and apply bird and fish habitat suitability models to projected climate change scenarios, and evaluate feasibility and effectiveness of adaptation strategies. The proposal was successfully funded in 2003 to support a two-year project.
The vulnerability assessment, adaptation strategies, and report were developed through the following activities:
- Use of historical aerial photographs to assess long-term changes in wetland plant community distribution. Photos from the Great Lakes region were analyzed for vegetation composition from the 1930s to 1999; periods of low water level occurred in the 1930s and 1960s, high water levels in the 1970s and 1980s. The photos were digitally analyzed using GIS software to examine the expansion and contraction of wetland vegetation communities in relation to Great Lakes water levels.
- Literature reviews, wetland surveys, habitat suitability models, and stakeholder input were used to assess the vulnerability of wetland bird and fish communities.
- Three Great Lakes coastal wetlands adaptation strategies were evaluated:
- Wetland dyking – by comparing paired dyked and undyked coastal wetlands on Lake Erie and Lake Ontario;
- Review of existing policy and land use planning processes to assess viability of adaptation via policy processes; and
- Large-scale water level regulation to reduce impacts of changing water levels.
- Stakeholder consultations through meetings and interviews were conducted to aid in project scoping and design, to obtain feedback on key vulnerabilities and thresholds, and to obtain feedback on climate change adaptation scenario evaluations.
Vulnerability indices were developed for coastal wetland plant species. Plants were categorized into low, moderate and high risk groups based upon their drought-tolerances and modes of colonization. Highly vulnerable plant species included wild rice and Hill’s pondweed; least vulnerable were several invasive species such as purple loosestrife and common reed. Models were developed based upon GIS analyses of historical photos to link vegetation community types with average water depths. This was then used to assess potential climate-related impacts.
Bird models were based upon available survey data of breeding bird abundance in different habitats. Regression equations were developed using bird abundance relative to wetland habitat availability. Fish models were also developed based on life stage preferences to estimate habitat suitability and thermal preferences. A Habitat Alteration Assessment Tool was used to identify suitable fish habitats based upon depth, vegetation type, and substrate type for six fish guilds in three life stages. Assessments were conducted using four climate change scenarios; two extremes representing the wettest and warmest conditions and driest and warm conditions and then two moderate wet/dry warm conditions.
Project Outcomes and Conclusions
Results from the vulnerability assessment indicated that lower water levels will impact the distribution and abundance of wetland vegetation and bird and fish communities. Wetlands within lacustrine embayments were most resilient to the impacts of a lowered water table. The largest impacts were seen in riverine wetlands. Both the bird and fish vulnerability models provided inconsistent results and highlighted the need for large-scale assessments to determine higher trophic level responses to climate change.
The adaptation strategy that was ranked as the highest priority was developing and implementing effective land use planning and policies to protect the natural processes that create wetlands. The final report, released in 2006, concluded that research efforts should be focused on verifying plant and animal vulnerabilities to climate change and collecting high quality hydrological data (Mortsch et al. 2006).
Feifel, K. M. (2012). Great Lakes Coastal Wetland Communities: Vulnerabilities to Climate Change and Adaptation Strategies [Case study on a project of Environment Canada]. Product of EcoAdapt's State of Adaptation Program. Retrieved from CAKE: www.cakex.org/case-studies/great-lakes-coastal-wetland-communities-vulne... (Last updated October 2012)