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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 along the Sydenham River © Smera Sukumar


This spectacular 117-hectare (288-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.

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.

In 2021, our community rallied once again to support the acquisition of a 100-acre property, expanding the nature reserve and protecting more mature forest and wetlands.

Bluebells, Sydenham River Nature Reserve © Smera Sukumar

Plants and Animals

The nature reserve property 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:

  • 38 species at risk including birds, plants, reptiles, fish and, of course, freshwater mussels;
  • 34 species of mussel, 16 of which are listed as at-risk provincially or nationally making the property the freshwater mussel capital of Canada; and
  • Half of Ontario’s bird species breed in or pass through the area during migration.
Great spangled fritillary butterfly © Noah Cole


To protect this rare habitat, this property does not have a marked trail system and is not open to members of the public. If you would like to visit the property and help with restoring the agricultural fields on this nature reserve, please check our events calendar for upcoming volunteer opportunities. If you have questions, please contact us at 416-444-8419 or reserves@ontarionature.org.

The nature 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 property, the nature reserve 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.

Golden eagle migrating above Sydenham River Nature Reserve © Mark Buchanan

“This 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 property 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, former Nature Reserve Coordinator

Sydenham River Nature Reserve © Larry Cornelis


The nature reserve does not have a trail network and is closed to visitors to prevent 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 Nature Reserve © David Coulson

Tallgrass meadow © Gabriella Zagorski
Sydenham River Nature Reserve

The Sydenham River Nature Reserve is generously supported by:

Government of Canada logo
Lambton Wildlife Inc logo
Sydenham Field Naturalists logo
The Comart Foundation
TD Friends of the Environment logo

Thank you to each of our generous Ontario Nature members and supporters who helped to expand the nature reserve in 2021. We gratefully recognize the following supporters:

Government of Canada logo
Lambton Wildlife Inc logo
Sydenham Field Naturalists logo
Ontario Land Trust Alliance logo
Essex County Field Naturalists logo
Aecon logo