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Sydenham River Nature Reserve

A largely-wooded biodiversity oasis in a landscape dominated by cash crops such as corn and soybeans.

Virginia bluebells and Sydenham River © Smera Sukumar


This spectacular 193-acre property forever protects one of Ontario’s most biodiverse waterways. In 2014, two member groups – Lambton Wildlife and the Sydenham Field Naturalists – alerted Ontario Nature about a special property on the mussel-rich Sydenham River that was up for sale. After some initial discussions and exploring the property, Ontario Nature signed an agreement to purchase, pending raising $860,000.

The creation of the Sydenham River Nature Reserve in the Carolinian Life Zone was announced on December 19, 2016. Many individuals, foundations and organizations gave generously in support of this effort. Lambton Wildlife and the Sydenham Field Naturalists were instrumental in the fundraising, and now share the responsibility to steward the property with Ontario Nature.

Bluebells, Sydenham River Nature Reserve © Smera Sukumar

Plants and Animals

The reserve saves a ribbon of extraordinary diversity of plants and animals in a region that is under intense pressure from development driven by hosting 25 percent of the Canadian population:

  • 23 species at risk including birds, plants, reptiles, fish and, of course, freshwater mussels;
  • 34 species of mussel, 11 of which are listed as at-risk provincially or nationally making the property the freshwater mussel capital of Canada;
  • Half of Ontario’s bird species breed in or pass through the area during migration.
Great spangled fritillary butterfly © Noah Cole


Ontario Nature is focusing on the restoration of the natural forest habitat on the reserve. During this time, we ask that you refrain from visiting. If you would like to help with the restoration, please check our events calendar for upcoming volunteer opportunities. If you have any questions, please contact us at 416-444-8419 or reserves@ontarionature.org.

The reserve represents some of the provinces best remaining examples of imperiled and vulnerable habitats. An almost two-kilometre stretch of the Sydenham River winds through the middle of the property. Representing Ontario Nature’s first riverine reserve, the property is teeming with life.

This riverside property is a largely-wooded biodiversity oasis in a landscape dominated by cash crops such as corn and soybeans. It forms part of the Carolinian Canada Sydenham River Signature Site, so designated because it was identified as a critical natural area. There are major challenges conservation organizations face in sustaining the ecological connections and biodiversity along the river corridor.

Sydenham River Nature Reserve BioBlitz © David Coulson
“Sydenham River Nature Reserve is filled with ridges and valleys that were carved out thousands of years ago by rivers formed when the glaciers were retreating. Home to 23 species at risk, this is one of our most diverse nature reserves. With the help of our donors, partners and stewards, we are restoring four old farm fields to forest habitat. Once complete, this reserve will become the largest contiguous patch of forest along the Sydenham River! It will provide a refuge for at-risk species while allowing visitors to experience the wonder and beauty of the property.”
– Gabby Zagorski, Nature Reserve Coordinator


The reserve is open to visitors and Ontario Nature is already planning to create new trails so that the public can explore this extraordinary landscape without damaging sensitive flora and fauna.

If you have any questions, please contact Ontario Nature at 416-444-8419

View Sydenham River Nature Reserve in a larger map.

Sydenham River © David Coulson

Tallgrass meadow © Gabriella Zagorski

The Sydenham River Nature Reserve is generously supported by:

Thank you to each of our determined members and supporters who helped protect this biodiverse property. We gratefully recognize the following supporters:

Visiting Our Nature Reserves Update

Our Nature Reserves are open to the public, but before visiting please review our COVID-19 Update that we posted on April 19, 2021.