Embayment D Wetland Creation
Embayment D is one of the smaller lagoons and shallow except for a small depositional zone of deeper water toward the north side. There is a complete absence of rooted aquatic plants within the Embayment, with no significant emergent or submergent vegetation communities. The absence of vegetation combined with the dominance of cladophora algae is consistent with the conditions associated with an abundance of common carp. The shallow warm water is ideal spawning habitat and large numbers of carp congregate within the Embayment in the spring. Their spawning and foraging behaviours uproot plants and create turbid conditions that impede the establishment and growth of submerged, emergent and floating vegetation.
The vision for Embayment D is a 5.8 hectare coastal hemi-marsh, however to achieve this large carp must be restricted from the Embayment. A berm will be constructed at the western edge of the Embayment to provide a physical separation from the Outer Harbour and a water level control structure/carp barrier will be installed to control water levels and allow the free passage of fish – except for large carp. Additional plans for this site include the construction of small islands on the west side of the berm to afford more protection to the berm and to provide wildlife habitat, particularly colonial waterbirds.
Shorebird Habitat Creation
Although TTP is a frequent stopover for some migratory shorebirds, there are few resident species and only small numbers of migrants. This is due to the lack of suitable habitat at TTP that shorebirds require to rest, forage and nest. The Shorebird Habitat Creation Project will turn an area in the Toplands into a two basin, multi-function, managed wetland that targets shorebirds, but also provides habitat for other migratory waterbirds. Once the basins are excavated to remove inorganic material, clay will be added to the bottom to create a less permeable liner and organic substrate applied to provide habitat for invertebrates – a staple shorebird food. Water depth is critical for shorebirds, so water levels will be controlled using water control structures and pumps. During peak migration periods water depth will be managed to create ideal foraging and roosting areas. Other habitat features including small islands and logs will be added to increase overall habitat diversity and availability.
Neck Meadow Enhancements
Two nodes on the east side of the Neck will be enhanced for meadow species including nesting waterfowl, songbirds, small mammals and butterflies. Landform may be slightly modified to create a more varied range of exposures and moisture conditions. Soil additions and amendments will aid in the success of tree and shrub plantings along the edges that will provide shelter from the prevailing winds. Herbaceous vegetation seeding and control of exotic invasive species will increase the biodiversity of the areas.
Triangle Pond Habitat Enhancement Project
This 0.8 hectare wetland was actually the test case for the large scale Cell One Wetland Creation Project as it was also used to dispose of contaminated sediments collected from dredging activities. Before project implementation the pond was featureless with few habitat attributes and little vegetative cover. The goal of the Triangle Pond project was to enhance and diversify the habitats within Triangle Pond. To accomplish this, the existing pond was drained, capped with clean fill to contain contaminated sediments and re-graded to create the correct conditions for a functional marsh and diversify substrates. Structural habitat components were added to improve habitat for various wildlife species and terrestrial and aquatic plants were installed to enhance the overall area and provide linkages with existing habitat features in the park and other habitat enhancement initiatives. Although the exotic invasive common reed (Phragmites australis) continues to be a problem in Triangle Pond, since its completion in 1999 this wetland has provided functional habitat for a variety of species including beaver, muskrats, herpetiles, fish, wading birds, fish-eating birds and waterfowl.
Northern Pike Spawning Channels
Northern pike are a top predator in the Toronto waterfront fish community, but until recently were absent from the harbour. Their comeback in Toronto is due to initiatives to improve water quality and aquatic habitat. By studying pike and targeting habitat improvements to them, many other species further down the food web benefit. The presence of pike in the Toronto waterfront is a positive sign and provides valuable information about the state of the harbour. Although TRCA has undertaken habitat improvements targeted to pike in many locations along the waterfront, TTP is the focus of three habitat creation initiatives for pike. Embayments B and C had shallow channels cut into the shoreline to create conditions preferred by pike for spawning. Embayment B was also planted with aquatic vegetation to further enhance spawning habitat, however due to erosion concerns Embayment C was not planted. Since the completion of the channels in 1997, pike in spawning condition have been observed in both locations. More recently Cell One was the focus of targeted pike habitat. Hummocks were constructed and planted with aquatic vegetation to provide suitable spawning habitat.
For more information on completed habitat creation and enhancement projects please refer to the document Tommy Thompson Park Public Urban Wilderness: Habitat Creation and Enhancement Projects 1995-2000