Marsh Status Review: Cootes Paradise and Grindstone Marsh 1994-2022

By Tys Theijsmeijer, Senior Director of Ecosystem Stewardship Programs and Policy

As part of the periodic technical review and publication of the recovery status for the Hamilton Harbour Area of Concern under the Great Lakes Water Quality Agreement, ongoing benchmark monitoring within the Royal Botanical Gardens marsh areas is summarized. Overall recovery progress is ongoing, with about one-third of the habitat recovered. However, recovery continues to be limited by inflowing water quality issues that have yet to be remediated. This poor water quality favors invasive fish species such as Common Carp and Goldfish. Since two-thirds of the habitat has not yet recovered, the associated fish and wildlife populations remain limited.

The most surprising outcome is the limited recovery of fish and wildlife populations, despite the presence of large areas of dramatically improved, good-quality habitat. Wildlife species, particularly amphibians, are the most limited in recovery, although some successes have been found in the monitoring. Migratory birds are present seasonally, and a few species have returned, including the Bald Eagle, Trumpeter Swan, and Osprey. Additionally, the reemergence of several marsh mammal species and the return of Gray Treefrogs throughout much of the recovered habitat have been notable successes.

Large-scale recovery of marsh habitat is visible at Cootes Paradise, particularly at Westdale Inlet (via Princess Point Trail), the Spencer Creek delta area (Marshwalk Trail), and the upper Grindstone Marsh area (Bridle Trail Loop Trail).

The last published review of the status of Hamilton Harbour’s Great Lakes Area of Concern is briefly covered in the Hamilton Harbour Fish and Wildlife Factsheets 2018, while the last detailed in-depth report is the HHRAP Stage 2 update (2003). The current Royal Botanical Gardens document summarizes the status of fish and wildlife populations and habitat recovery progress for the two Lake Ontario coastal marsh areas within RBG’s properties, as measured through various monitoring programs. The report supports the broader Hamilton Harbour 2022 status review for Beneficial Use Impairments (BUI) numbers iii – Fish and Wildlife Populations, and xiv – Fish and Wildlife Habitat. This document is an amalgamation of technical documents provided by the Royal Botanical Gardens through the HHRAP Fish and Wildlife Committee status review.