Two of London's publicly owned Environmentally Significant Area (ESAs) are Provincially Significant Wetlands - Westminster Ponds/Pond Mills and Sifton Bog.
Westminster Ponds/Pond Mills
Located south of Commissioners Road and east of Wellington Road, this ESA is adjacent to the Tourist Information Centre and extends eastward to Pond Mills Road. At approximately 250 hectares, Westminster Ponds/Pond Mills is the largest Environmentally Significant Area (ESA) in London and is also designated as a Provincially Significant Wetland. This site provides a great variety of upland forest, old field meadow and wetland natural habitats within the boundaries of a major urban centre. Approximately 60 per cent of all plant species found in Middlesex County grow in the Westminster Ponds/Pond Mills ESA, including 30 plants that are nationally and/or provincially rare.
Westminster Ponds/Pond Mills ESA is located on the Ingersoll Moraine and is geologically and botanically interesting. The Ingersoll Moraine is the oldest and most northerly moraine of the Erie ice lobe. The ponds themselves are “kettle lakes” created in this glacial clay area 14,000 years ago by the melting of large blocks of glacial ice (Dreimanis, UWO). Three ponds are associated with Westminster Ponds area – Saunder’s Pond, Tumbleson’s (Fish and Game) Pond and Spettigue’s Pond. Two ponds are located in the Pond Mills area – the North and the South Ponds, and the ravine known as Dayus Creek Valley joins these two areas. This valley contains one large and several smaller ponds. Because of its varied topography and drainage, this ESA support an interesting combination of woodland, bog and meadow habitats. Wetland habitats are associated with the lowland areas and around the margins of the ponds and include deciduous swamp, peat bog, and cattail marsh.
The ESA's four main access points lead to 11 km of trails. Most of the trails are gently rolling with the occasional short, steep hill. Almost all the trails are on clay or muck soils, which are prone to becoming muddy. Boardwalks cross some lowland areas.
The ponds and the mixture of habitats make this site an excellent place to view wildlife. More than 200 species of birds have been recorded in the area. It is an important stopover for migrants, with almost all the warblers, flycatchers, thrushes and finches in the London area being reported, as well as ducks, grebes, herons and other water-birds. Summer residents include forest birds such as Great Crested Flycatcher and Wood Thrush, and open-country species such as Field Sparrow and Easter Meadowlark. Great Horned Owl and Red-tailed Hawk also nest in the ESA.
Mammals common to urban areas may be seen in the ESA. Beaver, Coyote and White-tailed Deer are relatively recent arrivals. In wet areas, you may hear or see several frog and toad species. Turtles and snakes bask in open areas or on fallen logs, while salamanders find shelter in dark places. Several species of fish have been recorded in the ponds, although not in great numbers. As well, watch for insects such as dragonflies, damselflies and butterflies.
Sifton Bog is located on the south side of Oxford Street west of Hyde Park Road, just west of Oakridge Mall. Park at Oakridge Mall on the north side of Oxford Street and enter through the small pedestrian gate in the left-hand fence on the south side of Oxford Street.
The Sifton Bog contains an acidic shrub kettle bog that supports a disjunct, or relict plant association that is common in more northern latitudes around the world. The bog is surrounded by woods that support Carolinian plant species that commonly occur in more southern latitudes. One can experience in a ten minute walk changes in vegetation that could take a journey of several hundred kilometres. Because it is the most southerly large bog in Canada, it is an invaluable area for research and education, the more so due to its location within a large urban centre. The Sifton Bog is recognized by the MNR as a Provincially Significant Wetland and a regionally significant Area of Natural and Scientific Interest (ANSI).
The bog depression formed during the same glacial period as Westminster Ponds/Pond Mills , some 14,000 years ago. When the large ice block melted it left a depression in the underlying glacial till and formed a “kettle lake”. The lake once occupied the entire basin, but over time vegetation has established, reducing the size of the lake by infilling. Today, the “eye of the bog” is referred to as Redmond’s Pond and it is the area immediately surrounding the pond that supports a unique association of specialized plants adapted to the nutrient poor, acidic, cool conditions.
Look for the trail at the southwest end of the paved area. It leads south through wet woods to the start of the boardwalk onto the floating bog. The boardwalk ends at a viewing platform on Redmond's Pond. To protect the fragile plants in the bog, please stay on the boardwalk. Water levels fluctuate, and rubber boots are needed in the spring and after summer rainstorms.
The most fascinating plant life is found in the central area around Redmond’s Pond. The floating mat consists of a thick layer (0.5m to 2.0 m) of Sphagnum moss, alive in the aerated upper surface, called the “acrrotelm” and slowly decaying into greenish gray organic muck within the anaerobic (without oxygen) lower surface, called the “catotelm”. Many of the plants on the mat are tiny, like Bog Cranberry and Sundews, The latter plant, plus Pitcher Plant and Bladderwort are carnivorous plants that have specialized leaves for trapping and digesting insects to provide them with the required nutrients. In late June to early July, one will see pink flowers scattered on the bog mat. These are orchids, the two commonly observed ones are Rose Pogonia and Grass-pink.
Redmond's Pond is surrounded by the floating sphagnum mat, and is gradually decreasing in size as the peat advances. The fluctuating water levels sometimes reveal mucky areas overtop of water, called a "false bottom." This area is habitat for the rare Smith's Bulrush and several species of spike rushes and sedges. In the open water there is Water-shield, bladderwort and yellow pond lily or "spatterdock," a rare plant.
In spring and fall, numerous species of warblers, sparrows and other migrants can be found. In some winters, the cones of Black Spruce and Tamarack attract the "winter finches" - Evening and Pine Grosbeaks, White-winged Crossbills, Pine Siskins, Common Redpolls and Purple Finches. As with the plants, the more northerly mammals are found in the heart of the bog. Raccoons, Striped Skunks and Woodchucks are found on the slopes, while Eastern Chipmunks, Short-tailed Shrews and Grey Squirrels are in the low, damp woods. Among the shrubs on the floating bog live Eastern Cottontails and in the moss, though seldom seen, are Masked and Smoky Shrews. Muskrats have been reported in Redmond's Pond.
Because the pond is permanent and the sphagnum mat is always damp, the bog is ideal for turtles and frogs. Of the four species of turtles that have been recorded, the Painted, Snapping, Blanding's and Spotted, the last two have not been found in many years. Six kinds of frogs are known: Green, Leopard, Wood, Chorus, Gray Treefrog and Spring Peeper. A seventh species, the Pickerel Frog, has not been recorded at Sifton for many years. American Toads live among the shrubs on the sphagnum mat.
Certain butterflies, moths and other insects are found here because of the acidic bog plants. These include the Pitcher-plant Moth, the Bog Copper Butterfly (right), which feeds on the cranberry plants, and the Bog Elfin, which feeds on the blueberry plants. Bog Crickets can be found in the sphagnum moss. In the late spring and summer, visitors will encounter abundant mosquitoes.