Assessing the ecological value of wetlands using the MACBETH approach in Quebec City

Wetlands offer many social and ecological benefits, including by being highly productive environments, regulating climate and the global nitrogen cycle, supporting biological diversity, providing recreational and cultural services, reducing flood peaks, retaining sediment and contaminants, purifying water, acting as preferred groundwater recharge and discharge areas and providing habitat for wildlife. However, wetlands in urban regions are often threatened by development, which can fragment them, thus reducing the biodiversity and long term survival of such wetlands. On average, 50–55% of total wetland area has been lost in the United States and Canada since the European settlement. Many communities have therefore developed strategies, regulations and programs to protect their remaining wetlands. These initiatives often require that permit providers or planners who design such conservation strategies evaluate the costs and benefits of wetlands to society, but rarely that they define a method for this assessment. This study presents a method that was developed in collaboration with the City of Quebec to systematically assess the ecological value of wetlands within its boundaries. An index was created with a group of experts using the MACBETH approach. This process resulted in all 1347 wetland complexes in Quebec City being classified based on their ecological value. The model created on the basis of the decisions taken by consensus during the workshop appears to be an effective tool to provide an overview of the wetlands in Quebec City. The results are convincing and they accurately represent the perceptions expressed by the expert panel.