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Wetlands are Biodiversity Support Systems

American avocet and greater yellowlegs, Hillman Marsh Conservation Area © Noah Cole

Consistent with the understanding that no element of nature exists in isolation, the climate crisis is known to be deeply connected to a second and simultaneous crisis: global biodiversity loss. Wetlands are among the Earth’s most productive and biodiverse ecosystems. Unfortunately, species in Ontario’s wetlands and other ecosystems across the world are struggling to adjust to rapidly changing climatic patterns affecting their habitats, food sources and their own behavioural cycles. Furthermore, biodiversity loss accelerates and intensifies the impacts of climate change, as decreasing biodiversity reduces an ecosystem’s ability to mitigate and adapt to climate change.

Protecting, restoring and maintaining connectivity among wetlands in Ontario is therefore critical to ensuring the survival of all lives that depend on them and maximizing their climate benefits.

Target 8 of the Kunming-Montreal Global Biodiversity Framework, endorsed by Canada and 187 other governments at the 15th Conference of the Parties, commits to minimizing the effects of climate change on biodiversity and creating positive outcomes for biodiversity through climate action, including the use of nature-based climate solutions and other ecosystem approaches.

© Kirsten Dahl

Wetlands Provide Critical Habitat

Canada hosts 37 Wetlands of International Importance identified under the Ramsar Convention on Wetlands, also called Ramsar Sites. Eight of these sites are in Ontario and all are extremely biodiverse:

  1. They host a diversity of wetland types: marshes, swamps, bogs, fens and coastal wetlands;
  2. They provide critical habitat for migrating and breeding birds, bats, reptiles, amphibians and other species (including many species at risk); and,
  3. They support hundreds of plant species, including species of provincial and national significance.

The biodiversity value of Ontario’s wetlands is not limited to this handful of internationally recognized sites. Wetlands across the province are crucial for maintaining species diversity. Recent research has highlighted, for example, their significance for wild bees and for populations of at-risk species such as common nighthawks and eastern whip-poor-wills.

Greater yellowlegs and midland painted turtle © Sharon O'Connor

Spotlight: Rattray Marsh

Rattray Marsh is the only remaining lakefront coastal marsh between Burlington and Toronto. The marsh occurs on the Treaty and traditional territory of the Mississaugas of the Credit First Nation, the Haudenosaunee Confederacy and the Huron-Wendat and Wyandot Nations. Well recognized for its ecological value, it is protected within the Rattray Marsh Conservation Area and has been managed by Credit Valley Conservation (CVC) since the early 1970s.

A Natural Area Inventory conducted by CVC and the Region of Peel provides detailed information about the Rattray Marsh. The area hosts diverse vegetation communities, including shallow marshes deciduous swamps. It supports over 500 native plant and animal species, 29 of which are provincially or nationally listed species at risk. Many of these species rely specifically on the wetland for their survival, including several wetland birds, reptiles and amphibians.

CVC continues to actively manage this important wetland so that it may continue to provide important habitat and ecosystem functions to support its diverse inhabitants now and in the future.

Rattray Marsh Conservation Area © Gary J. Wood CC BY-NC-SA 2.0

Wetland Biodiversity is Vulnerable

Wetlands across the province provide vital habitat for at least 20 percent of provincially listed species at risk. This includes Ontario’s eight native turtles which are all considered to be provincially or federally at risk. Maintaining and enhancing wetland habitats is key to protecting these species from further decline.

Even common wetland species, like muskrats, are vulnerable to wetland loss and degradation. Researchers found marked muskrat declines, for example, in Point Pelee National Park and Matchedash Bay-Grey Marsh – two of Ontario’s eight Ramsar Sites. They speculate that this may be due to declining quality of wetland habitats resulting from biodiversity loss and reduced connectivity, once again highlighting the need to maintain and enhance Ontario’s wetlands within and beyond formally protected areas.

Blanding's and midland painted turtles © Joe Crowley

The vulnerability of wetland-dependent species to disturbance demonstrates that protecting and restoring Ontario’s wetlands is of utmost importance in an era of climate change.

© Kirsten Dahl

Spotlight: The Nabish Wetlands

The Nabish Wetland Complex is a large provincially significant wetland complex in the territory of the Migisi Sahgaigan First Nation – near what is now known as Dryden, Ontario.

Comprised of a mixture of fens, marshes and swamps, the Nabish Wetlands provide critical habitat for numerous plant and animal species. Particularly notable are breeding birds such as least bittern, black tern, Le Conte’s sparrow, Virginia rail, trumpeter swan, red-necked grebe and sedge wren. Several of these species are declining or at-risk and vulnerable to climate change.

Local naturalists are seeking permanent protection of the Nabish Wetlands so that this valuable ecosystem may continue to support all the diverse lives that depend upon it.

Virginia rail, Nabish Lake wetlands © Darlene Salter

Connections and Diversity

No element of biodiversity exists in isolation. Maintaining and enhancing connections within and among wetlands and other ecosystems is critical to reducing biodiversity loss as well as mitigating and adapting to the impacts of climate change.

Natural corridors that connect wetlands and other ecosystems support wildlife movement and interactions, enabling species to move and find suitable habitat in response to climate change and other stressors. They also support other critical natural processes such as pollination.

Furthermore, ecosystems with high biodiversity tend to be more resilient to the impacts of climate change. In fact, restoring populations of just nine key animal species or species groups could significantly limit global climate change by enhancing carbon storage in their respective ecosystems. This phenomenon has been observed across a vast array of ecosystem types, including wetlands.

Copeland Forest © Ruth Noland-Flores

Protecting and restoring wetlands is critical to maintaining Ontario’s numerous wetland-dependent species, which is important due to their intrinsic value as well as their role in the broader web of life.

© Kirsten Dahl

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This online primer was made possible through the generous support of the Greenbelt Foundation, The McLean Foundation, the K.M. Hunter Charitable Foundation and the John and Pat McCutcheon Charitable Foundation.