Many of Canada’s rivers no longer flow freely due to dams and other barriers restricting the movement of our native species. Watersheds have become degraded by human development to the point where many rivers are cut off from their floodplains, affecting many of the critical services provided by healthy ecosystems. Scientists are now exploring the concept of “Rewilding”, which aims to reconnect the critical base functions of river ecosystems as a long term solution to sustain healthy watersheds for future Canadians.
“Rewilding is an important take on restoration,” according to Research Affiliate Program Student with Environment and Climate Change Canada, Natalie Kathleen Rideout. “It is this idea of helping humans get out of the way allowing nature to heal itself and to trust that nature knows best”. This concept has gained a lot of popularity in Europe, but remains largely unexplored by scientists in North America. Natalie and her fellow ECCC scientists and colleagues from the Canadian Rivers Institute at the University of New Brunswick are developing practical methods for using Rewilding to heal our rivers and their watersheds.
Assessing Rewilding potential
In their recent perspective paper, Rewilding watersheds: using nature’s algorithms to fix our broken rivers, Natalie and her colleagues are proposing a framework to assess the potential of Rewilding by measuring basic river ecosystem functions: including structural components (like flood/flow pulse), functional components (like a river’s metabolism) and biotic components (living components such as micro-organisms, animals, plants). “We carried out a systematic literature review based on 90 peer-reviewed papers and looked at the links between each of these functions and identified rewilding goals”, Natalie explains. For example, restoring a river’s natural flow by removing dams, could overwhelmingly affect all the ecosystem functions. However, looking at one single component of the ecosystem is not the best approach because it will not guarantee a healthy ecosystem, according to Natalie. Hence, using the open available data that monitors rivers’ ecosystem functions can help identify rewilding actions and where to implement them.
What are the challenges?
Rewilding Rivers does not come without challenges. The first one is the need to have an available data collection over space and time for all ecosystem functions and components. Natalie and her colleagues found that “a lot of these ecosystem functions are not regularly monitored, particularly at a broad scale”. She also notes, “most of the biotic information is based within the ice-free period. So, we do not know a lot about what goes on in our rivers in the winter when the weather is extreme.”
The second challenge is how to allow nature to regenerate, to heal itself without threatening the livelihood of the many populations depending on freshwater ecosystems. “Allowing nature to regenerate doesn’t mean to ask people to vacate all the areas,” Natalie says. “It’s just trying to find the balance between our societies and nature and allowing it to be wild because that is going to benefit everybody”. Finding this balance needs conversation, knowledge sharing and a societal uptake. But most importantly, finding the balance is also identifying where to prioritise Rewilding. Highly degraded areas with reduced biodiversity or existing highly protected areas are not necessarily the best areas to prioritize for rewilding whereas vulnerable rivers with reduced functions are. The team is currently working on a preliminary case study in the Wolastoq | Saint John River in Atlantic Canada (one of 11 priority places identified by ECCC for species at risk conservation), to explore their proposed framework and help identify places where rewilding can have the best outcomes for healthy ecosystem functioning.
A holistic approach
This case study is an attempt to promote rewilding as a holistic approach to restore rivers and watersheds in Canada. The research team aims to continue getting relevant (new or existing) data to inform use of this approach in other geographic regions and include more biological diversity.