Natural areas are wetlands, meadows, forests, valley lands and other relatively undisturbed lands that are home to many different plants and wildlife.
Some contain rare plants, wildlife or landforms, or have features characteristic of the region before European settlement, or are especially large or diverse in habitat. Many natural areas are considered environmentally significant on a local, regional, provincial or even national scale.
There are many classifications for natural areas. Ontario’s wetlands are evaluated through the Ministry of Natural Resources (MNR) Wetland Evaluation System (1993) for their biological, social, and hydrological components and special features. A wetland that is scored high in all four categories will receive a higher class ranking, with Class 1 being the highest.
- Provincially Significant Wetlands – protected under Provincial planning policy.
- Locally Significant Wetlands – protection by local government encouraged.
- Environmentally Significant Areas (ESAs) – significant natural areas, designated for protection by the municipality. The City of London has designated 16 ESAs.
- Candidate ESAs – significant natural areas being considered for protection by the municipality.
- Areas of Natural and Scientific Interest (ANSIs) – areas designated by the MNR, chosen as representative of certain biological regions.
- Significant Natural Areas – areas of local significance.
- Conservation Areas – areas owned and/or managed by Conservation Authorities for public use and enjoyment, protection of habitat, and/or flood control.
Wetlands are areas that are seasonally or permanently flooded by shallow water, as well as areas where the water table is close to the surface. The four major types of wetlands are swamps, marshes, bogs and fens. Many of the 100 or so evaluated wetlands scattered throughout the Thames watershed form the headwaters of the river system. In the upper Thames River watershed there are 31 provincially significant and 35 locally significant wetlands. Deciduous swamps are the most common type of wetland. These swamps are dominated by Silver Maple, Black Ash, Black Willow and Swamp White Oak, with Red-Osier Dogwood, Buttonbush and Water Willow in the shrub layer.
- Ellice Swamp is the largest wetland in the watershed at 856 hectares. Located at the northern edge of the basin at the headwaters of Black Creek, Ellice is a Class 2 Provincially Significant wetland.
- Dorchester Swamp, east of London, has been designated as an Area of Natural and Scientific Interest (ANSI), a Carolinian Canada site, and a Class 1 wetland. This swamp is 548 hectares is size.
- Sifton Bog, which is a Class 2 wetland within the City of London, is considered the most southerly intact bog in Canada.
- Golspie Swamp, northwest of Woodstock, is one of the largest remaining wooded areas in Oxford County.