Drawing a line to protect the few remaining wetlands in Niagara By Dr. Anne Bell, Director of Conservation and Education, Ontario Nature. Wetlands provide critical habitat for wild plants and animals, including more than 20 percent of Ontario’s species at risk. They play a vital role purifying water, controlling floods, reducing erosion and mitigating climate change. These benefits, provided for free, are valued at over $51 billion per year in southern Ontario alone.