The natural shoreline of Lake Ontario, and the unique landforms of the Scarborough Bluffs have received the designation of a Natural Heritage System, Environmentally Significant Area and an Area of Natural and Scientific Interest.
Natural Heritage System
In June 2015, an Environmental Assessment Terms of Reference document on the Scarborough Waterfront Project was prepared by Dillon Consulting for the Toronto and Region Conservation Authority, and in this report, the natural features of this shoreline have been recognized for their environmental value (section 7.3, page 42):
Environmentally Significant Area's (ESA's)
Habitat loss is one of the major reasons for declining wildlife populations and some of the greatest biodiversity in Ontario is in the southern regions because of the warmer climate. Even though this area is surrounded by the urban metropolis of Toronto and region, the very fact that it is located in southen Ontario means that the area is likely to have more diverse mammal and bird populations. This unique landforms and geology of the bluffs have prevented this area from being over-developed which has contributed significantly to it's special designation.
Any dramatic alterations to the shoreline of this area will obviously impact this status.
The following information is taken directly from a comprehensive document prepared in 2012 for Toronto City Planning. The study team inlcuded North-South Environmental Inc., Dougan & Associates, Beacon Environmental Ltd. and some independent environmental consultants.
The criteria for the identification of Environmentally Significant Areas have been recognized as the following by the Official City Plan:
Areas of land or water within the natural heritage system with any of the following characteristics:
a) habitats for vulnerable, rare, threatened or endangered plant and/or animal species and communities that are vulnerable, threatened or endangered within the City or the Greater Toronto Area; or
b) rare, high quality or unusual landforms created by geomorphological processes within the City or the Greater Toronto Area; or
c) habitats or communities of flora and fauna that are of a large size or have an unusually high diversity of otherwise commonly encountered biological communities and associated plants and animals; or
d) areas where an ecological function contributes appreciably to the healthy maintenance of a natural ecosystem beyond its boundaries, such as serving as a wildlife migratory stopover or concentration point, or serving as a water storage or recharge area.
Most sites that qualified as Environmentally Significant Areas are associated with major river and creek valleys of the waterfront and ecological highlights include:
Rare forest vegetation types dominated by oak and pine and other shade-intolerant species that required periodic natural disturbance.
The presence of significant plant species associated with prairie and savannah habitats, at the northern edge of their range in this part of Ontario, or with particular affinities to Great Lakes Shorelines.
Confirmation of eight amphibian species, including six species considered significant in the City (i.e., northern leopard frog, bullfrog, wood frog, spring peeper, gray treefrog and eastern redback salamander).
Eight species of reptiles were observed in the surveyed sites (mainly in the larger sites along the waterfront): painted turtle, red-eared slider, snapping turtle, northern map turtle, Blanding’s turtle, eastern gartersnake, Dekay’s brown snake, and eastern milksnake. A total of 137 bird species were documented during the breeding season with 62 species considered locally or regionally significant, including a few area-sensitive species dependent on relatively large tracts or extensive grasslands and forests.
Seventeen mammal species were documented that are primarily common, adaptable species that occur in a wide variety of urban habitats, but notable species included the locally significant hairy-tailed mole and star-nosed mole
In addition to providing habitat for significant species, a number of the ESA's were documented as having ecological functions of significance to include the following:
presence of seepage areas;
presence of wetland areas indicating function as water storage;
function of the area as a linkage that provides a connection between habitat required to
complete a species’ life cycle;
significant habitat for migrating bird species;
habitat for colonial bird species; and
amphibian breeding habitat.
"The shoreline in the Project Study Area is designated as a natural heritage system (an area where protecting, restoring and enhancing the natural features and functions should have a high priority)" Environmental Assessment Terms of Reference Report
"ESA's are meant to capture the most locally and regionally significant terrestrial natural areas within the City’s natural heritage system" Environmentally Significant Areas in the City of Toronto