Provincial Policy Statement and Natural Heritage

By Andrea McDowell, originally published February 3, 2011

How natural heritage works in municipal planning

Counterintuitively, much of the protection for Natural Heritage in Ontario is driven by the Planning Act‘s Provincial Policy Statement, better known for driving urban density levels, development charges and zoning–but Natural Heritage is defined ecologically, rather than culturally:

2.1 Natural Heritage

2.1.1 Natural features and areas shall be protected for the long term.

2.1.2 The diversity and connectivity of natural features in an area, and the long-term ecological function and biodiversity of natural heritage systems, should be maintained, restored or, where possible, improved, recognizing linkages between and among natural heritage features and areas, surface water features and ground water features.

2.1.3 Development and site alteration shall not be permitted in:

1. significant habitat of endangered species and threatened species;
2. significant wetlands in Ecoregions 5E, 6E and 7E1; and
3. significant coastal wetlands.

2.1.4 Development and site alteration shall not be permitted in:

1. significant wetlands in the Canadian Shield north of Ecoregions 5E, 6E and 7E1;
2. significant woodlands south and east of the Canadian Shield2 ;
3. significant valleylands south and east of the Canadian Shield2;
4. significant wildlife habitat; and
5. significant areas of natural and scientific interest unless it has been demonstrated that there will be no negative impacts on the natural features or their ecological functions.


Blue Heron in the East Don River

This creates a close association between the Ministry of Natural Resources (MNR) provincially and the Municipality’s planning department, with the former feeding science, data and guidelines to the latter, who are then tasked with identifying and protecting significant natural heritage features.

“Ecological function” is what a Natural Heritage feature does for the surrounding environment: wetlands purify water; woodlands provide habitat and carbon sinks; valleylands permit animals to pass safely through the landscape, and so on. The MNR then develops manuals and guidelines setting out standards for determining which features are “significant,” including the Natural Heritage Reference Manual, Ontario Wetland Evaluation System (north and south), Significant Wildlife Habitat Technical Guide, and Ecological Land Classification manuals, among others. In many cases, the MNR has already assessed the provincial significance of Natural Heritage features, and the municipality then evaluates the local significance of the remaining woodlands, valleylands, wetlands, and habitat.

Ontario Ministry of Natural Resources, Natural Heritage Information Centre Biodiversity Explorer

The results feed in to the municipality’s Official Plan, which then determines what kinds of development restrictions would best protect the significant features (and frankly, even in rural areas, there often aren’t many left). According to Jane Weninger in the environmental planning department at the City of Toronto, a Natural Heritage System has been identified for Toronto, although it requires periodic updating to identify newly significant features. “It’s primarily located within the valleys and ravines and along the waterfront. These are areas that still retain a lot of their natural features, and they’re connected,” she says. “But the whole system is important because you can’t just protect the areas that are special because they don’t exist in isolation. They exist within this context of the broader system that supports them.”

The Natural Heritage System is being re-evaluated in Toronto right now, with final results expected in the next few months. The most significant features are protected from development under the Official Plan, unless the proponent can submit an environmental impact study showing that the proposed development would not negatively affect the feature’s ecological function. In this way, we can at least mitigate and hopefully, eventually, prevent or reverse the enormous deleterious effects of cities on their direct local environments, if not because it’s the right thing then because humans too depend on the ecological functions they provide, including clean water, clean air, and a healthy and resilient mix of wildlife species.

Andrea McDowell coordinates environmental approvals and studies for wind energy projects by day and writes about environmental issues by night. This leaves twilight for hiking all over Southern Ontario’s conservation areas, parks and trails, taking photographs and cataloguing whatever she finds there at her blog Zoopolis ( She has contributed to This Magazine, Spacing, Corporate Knights, Brain, Child and Send your questions or comments about natural heritage for possible use here to:

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