• Grizzly bear feeding on salmon in Chilko River

    A male grizzly bear feeds on sockeye salmon in B.C.’s Chilko River. Freshwater ecosystems in Canada and around the world are vulnerable to the effects of dams, pollution and invasive species, among other threats. (Photo: Jenny Stevens/Can Geo Photo Club)

In the last 50 years, freshwater ecosystems around the world have seen an 83 per cent decline in species populations due to pollution, overfishing and invasive species, but a new scientific paper says recovery is possible. 

Published in the journal BioScience on Feb. 19, the paper calls for immediate action to address freshwater biodiversity loss. 

“The purpose of the paper is to move beyond diagnosing the problem and to galvanize action to try and restore biodiversity in rivers, lakes and wetlands,” says Steven Cooke, a Carleton University biology professor and co-author of the paper. 

The paper, developed through a collaboration between the World Wildlife Fund (WWF), the International Union for Conservation of Nature (IUCN), Carleton University and other organizations, proposes six main actions to restore the health of freshwater ecosystems. These include letting rivers flow more naturally, reducing pollution, protecting critical wetland habitats, ending overfishing and unsustainable sand mining in rivers and lakes, controlling invasive species, and safeguarding and restoring river connectivity through better planning of dams and other infrastructure. 

To support their calls to action, the researchers also suggest practical measures, such as avoiding dams on the world’s remaining free-flowing rivers, treating more than 20 per cent of sewage before it is flushed into nature, and expanding and strengthening protected areas in partnership with local communities.

Cooke says that while the research has an international focus, restoring freshwater biodiversity should be a priority in Canada as well. 

“Canada has a disproportionate amount of water, and with that comes responsibility,” he says. “We should be global leaders in setting the standard and helping other countries achieve their goals.” 

Canada has about 20 per cent of the world’s freshwater supply, but is not immune to many of the problems impacting ecosystem health. In recent years, freshwater species such as mussel populations in southwestern Ontario and Pacific salmon in British Columbia have experienced rapid decline.

Cooke says while the situation both at home and abroad is dire, Canada has the capacity to lead for change. 

“Freshwater biodiversity is really part of Canadian culture so we’ve got a responsibility to do it right, but we’ve also got the ability,” he says. “Canada has the science capacity, the governance structure, strong NGO communities and a big base of volunteers that believe in the idea of the Canadian wilderness.” 

According to Cooke, the next step will be to apply the calls to action on a regional level, and get governments around the world to agree on a global restoration plan during the United Nations Convention on Biological Diversity being held in November this year. 

Related: The importance of Canada’s wild rivers