Using engineered structures to restore coastal wetlands

Session: 51. - Coastal Resilience

Karen McDonald, Toronto and Region Conservation Authority, [email protected]
Gord MacPherson, Toronto Region Conservation Authority, [email protected]
Rick Portiss, Toronto and Region Conservation, [email protected]
Danny Moro, Toronto and Region Conservation, [email protected]
John DiRocco, Toronto and Region Conservation, [email protected]

Abstract

Approximately 35% of coastal wetlands on the north shore of Lake Ontario have been lost, with higher losses likely occurring in urban centres like the Toronto region.  Remaining coastal wetlands in the Toronto area are degraded due to anthropogenic stressors including urbanization, lake-wide water level regulation, invasive species and common carp.  Restoration of these marshes is challenging since the factors related to their degradation are largely beyond the control of natural area managers.  Wetlands that incorporate structures that allow for water level management and the exclusion of large common carp have been successful in increasing aquatic vegetation with positive responses from both fish and wetland bird communities.  While the footprint of the structure may eliminate some aquatic habitat, the benefits of achieving improved habitat quality outweigh the minor losses of aquatic habitat.  Different types of engineered structures can be used to achieve wetland restoration targets, but must be designed and constructed to effectively address existing threats.  Duffins Corner Marsh, as well as Tommy Thompson Park wetlands benefitted from engineered structures, while wetlands at Humber Bay Marsh and Humber Bay Park did not perform as well.  

1. Keyword
wetlands

2. Keyword
coastal ecosystems

3. Keyword
Lake Ontario

4. Additional Keyword
urbanization

5. Additional Keyword
common carp

6. Additional Keyword
engineered structures