Environmentally Significant Areas are spaces within Toronto’s natural heritage system that require special protection to preserve their environmentally significant qualities.

In a city as densely populated as Toronto many high-quality natural areas still remain. Most of these natural areas are found in ravines, river valleys and along the waterfront, where they form the core of the city’s natural parklands system. Environmentally Significant Areas contain forests, meadows, wetlands and landforms, support an extraordinary variety of plant and animal life, and provide opportunities for people to experience wilderness in the city.

Most Environmentally Significant Areas reflect remnants of the original ecosystem. Others, such as Tommy Thompson Park, are man-made. Each Environmentally Significant Area has one or more of the following environmental qualities:

  • They are home to rare or endangered plants or animals.
  • They are large, diverse and relatively undisturbed which many plants and animals need to survive and reproduce.
  • They contain rare, unusual or high quality landforms that help us understand how Toronto’s landscape formed.
  • They provide important ecological functions that contribute to the health of ecosystems beyond their boundaries, such as serving as a stopover location for migratory wildlife.

Like all natural areas, Environmentally Significant Areas help to make the city a healthier place.  Plants filter air and water, help prevent flooding by absorbing storm water and help keep the city cooler in the summer.

Between 2009 and 2012, the City commissioned a scientific study to identify Environmentally Significant Areas across the city and understand their value using criteria in Policy 3.4.14 of the Official Plan. As a result of this study, 68 new areas were added to Map 12 of the Official Plan and the boundaries of 14 of the 18 existing Environmentally Significant Areas were expanded.

The interactive map shows Environmentally Significant Areas in more detail. For additional information, including the name of the area and a summary of characteristics that qualify the site, left click on the Environmentally Significant Area of interest.

Environmentally Significant Areas are particularly sensitive and require additional protection to maintain their unique environmental qualities. Development is not permitted and activities are limited to those that are compatible with the preservation of their natural features and ecological functions such as managed trails and viewing areas. Environmentally Significant Areas are protected by the Official Plan and zoning and by the Ravine and Natural Feature Protection By-law. Most Environmentally Significant Areas are located within the City’s parkland system, which is owned by the Toronto and Region Conservation Authority or the City of Toronto and managed by the City; some Environmentally Significant Areas are located on private land.

Environmentally Significant Areas are the ecological jewels of our natural heritage system; however they exist within a larger connected system. Continued management and protection of this larger system is essential to sustaining Environmentally Significant Areas and is an important part of protecting biodiversity within the city and beyond.

Environmentally Significant Areas are vulnerable to impacts from human use. Everyone can do their part:

  • Stay on official trails
  • Do not remove plants/animals
  • Keep dogs on leash
  • Do not dump debris on slopes
  • Landowners can plant native species and encourage regeneration of native species

Natural parklands do not have lawns to be mowed or fences to be painted, but they still require management to maintain and sometimes restore or enhance their ecological values. Management plans are in place for a number of Environmentally Significant Areas, such as High Park and Glen Stewart Ravine, and habitat restoration and trail work is underway in various locations. Further work is underway to develop management plans for 57 Environmentally Significant Areas that are managed by the City.

Invasive plants threaten the integrity of many of our natural areas. Invasive plants find their way into parklands by wind, flooding, seeding by wildlife tracking in seeds caught on pets, clothing and shoes, and the dumping of fill, garden waste and compost. Invasive species cannot be entirely eliminated from Environmentally Significant Areas, but the City of Toronto Urban Forestry Services group is currently working to control some of the established populations of invasive plants in natural parklands.

Encroachment by neighbours, dumping, mountain bikes, off-leash dogs, and the creation of ad hoc paths can degrade the quality of natural areas. The City of Toronto is working to manage the impacts of encroachments through removal, followed by restoration of natural areas, better signage and enforcement, and through the development of alternative sites for off-leash dogs and mountain bike skills parks (e.g. Sunnyside Bike Park).

Most Environmentally Significant Areas are located within our parkland system which also supports a range of recreational uses. It is important to balance access to and the protection of natural areas with recreational uses in order to maintain their significant qualities. The City of Toronto has been working with mountain bike user groups such as, Toronto Off-Road Bicycling Association (TORBA), and International Mountain Biking Association (IMBA) along with Park ‘Friends’ groups to communicate with park users to educate and seek their support for the protection of natural areas.