DIXIE HIGHWAY 407 1 Region of Peel NAI Area # 1304, 1320, 2449, 2625, 3961 Toronto and Region Conservation Authority City of Brampton Size: 36 hectares Watershed: Etobicoke Creek Con 4 E, Lots 13, 14 Ownership: 5% private, 95% public (Province of Ontario; City of Brampton; City of Mississauga) Subwatershed: Spring Creek General Summary This natural area is relatively large for an urban site. It provides a broad riparian area with a variety of wetland types and extensive open-country cultural communities that may support area-sensitive grassland birds. While surrounded by busy roads and industrial land use, the area is sparsely used by people and thus provides a refuge for wildlife in a busy urban setting. Most of this natural area is in public ownership. The area straddles the boundary between Brampton and Mississauga. This area occupies a key location at the intersection of two wildlife movement corridors, being the valley lands of Spring Creek, and a hydro corridor. Thus this area is an important hub connecting different natural areas. TRCA ELC surveyors, botanists and ornithologists have provided complete data coverage for the core NAI inventories (vegetation communities, plant species, breeding birds), plus incidental observations of other fauna over the delineated area (Table 1). Full species lists are not currently available however TRCA-tracked species and plant species that dominate communities are reported here. Table 1: TRCA Field Visits Visit Date Inventory Type 01 Aug. 2001 ELC 05 Sept. 2001 Flora 06 Sept. 2001 Flora Physical Features This area is in the Peel Plain physiographic region; characterized by flat to undulating topography. Soils of this region tend to be low- permeability clays, deposited when glacial meltwater ponded up over a layer of low permeability deposits. Spring Creek, a tributary of Etobicoke Creek, runs through this area. Spring Creek is joined by a smaller tributary near the middle of this natural area. Spring Creek was formerly referred to as East Branch Etobicoke Creek. Human History The former community of Fraser s Corners was located just over 1 km upstream from this natural area. It was named after the first settler Robert Fraser and had a church by 1854. The adjacent Highway 407 was opened in 1997 (Bevers, 2010; Hicks, 2006). Human use of this area is minimal, likely due to its wet/damp nature and industrial (as opposed to residential) surroundings. However, the large meadows between the tributary and main streams are extensively used by off-road vehicles.
DIXIE HIGHWAY 407 2 The natural area is bordered by Highway 407 to the northwest and by Bramalea Road to the east. Surrounding land uses include recreational soccer fields and associated drainage ponds to the southwest. These ponds presumably drain the playing fields and then drain into the tributary stream. A major hydro high-tension corridor extends across this natural area. Where the wires cross the stream, the valley vegetation beneath the hydro lines is occasionally cut to prevent trees from growing tall. Adjacent to the natural area, the land under the hydro lines is agricultural. A hydro substation is adjacent to the north of this natural area. South of the hydro corridor, the natural area is surrounded by industrial land use. Vegetation Communities The general community types present here are shrub beach bar (3%), deciduous forest (0.8%), marsh (11%), open aquatic (3%), cultural meadow (72%), cultural thicket (1%), cultural savannah (3%), cultural woodland (4%) and plantation (2%). Fifty-two plant communities were mapped for this area, comprised of 17 different vegetation types, none of which are provincially or regionally rare (Table 2). Two of these community types are considered to be TRCA regional Communities of Conservation Concern: Willow Shrub Beach (BBS1-2, L-rank L3) and Bur-reed Mineral Shallow Marsh (MAS2-7, L-rank L3). Additional community types are considered to be TRCA regional Communities of Urban Conservation Concern: Fresh-Moist Hawthorn Apple Lowland Deciduous Forest (FOD7-E, L-rank L4) and Broad-leaved Cattail Mineral Shallow Marsh (MAS2-1A, L-rank L4). Two communities of the Purple Loosestrife Mineral Meadow Marsh (MAS2-B) type are dominated by an invasive species. One of the communities was classified only to the ecosite level. Table 2: ELC Vegetation Communities Map reference * Vegetation type Size in hectares % of natural area BBS1-2 Willow Shrub Beach (8 communities) 1.06 2.99 FOD7-E Fresh-Moist Hawthorn Apple Lowland Deciduous 0.27 0.76 Forest MAM2-2 Reed Canary Grass Mineral Meadow Marsh 2.8 7.91 (3 communities) MAM2-B Purple Loosestrife Mineral Meadow Marsh 0.23 0.65 (2 communities) MAM2-10 Forb Mineral Meadow Marsh 0.04 0.13 MAS2-1A Broad-leaved Cattail Mineral Shallow Marsh 0.85 2.39 (2 communities) MAS2-7 Bur-reed Mineral Shallow Marsh 0.04 0.11 MAS2-A Common Reed Mineral Shallow Marsh 0.1 0.27 OAO1 Open Aquatic Ecosite 1.15 3.24 CUM1-A Native Forb Old Field Meadow (8 communities) 6.84 19.35 CUM1-B Exotic Cool-season Grass Old Field Meadow 17.99 50.88 (11 communities) CUM1-C Exotic Forb Old Field Meadow 0.52 1.46 CUT1-A1 Native Deciduous Sapling Cultural Thicket 0.49 1.38 (3 communities) CUS1-1 Hawthorn Cultural Savannah (4 communities) 1.03 2.91 CUW1-A3 Native Deciduous Cultural Woodland (3 communities) 1.29 3.65 CUW1-D Hawthorn Cultural Woodland 0.1 0.27 CUP2-A Restoration Mixed Plantation 0.58 1.64 TOTAL AREA INVENTORIED 35.38 * Note: The map reference code refers to the vegetation type shown on mapping for this area and also to the Appendix list of species typically encountered in this vegetation type.
DIXIE HIGHWAY 407 3 Species Presence Vascular Plants At least 68 species of vascular plants are present in this natural area, of which 36 (53%) are native. Three plant species here are considered to be TRCA regional Species of Conservation Concern and an additional five species are TRCA regional Species of Urban Conservation Concern. One of the communities here is a Restoration Plantation with planted TRCA Species of Conservation Concern and TRCA Species of Urban Conservation Concern (Silver Maple, Acer saccharinum; Honey Locust, Gleditsia triacanthos; White Spruce, Picea glauca; White Pine, Pinus strobus). These species are excluded from the table as they are not naturally-occurring. Also, Fragrant Sumac (Rhus aromatica) occurs in a meadow community dominated by exotic species and is likely planted, as TRCA considers this species to be extirpated in the Etobicoke Creek watershed. This species has not been included in the table of naturally-occurring TRCA Species of Conservation Concern. Table 3: Regionally Rare Species (shown in bold), TRCA Regional Species of Conservation Concern (L1-L3), and TRCA Regional Species of Urban Conservation Concern (L4) (Kaiser, 2001; Toronto and Region Conservation Authority, 2007) Scientific name Common name S rank G rank L-rank VASCULAR PLANTS Symphyotrichum ciliolatum Lindley s Aster S5 G5 L3 Betula papyrifera Paper Birch S5 G5 L4 Rosa blanda Smooth Rose S5 G5 L4 Sagittaria latifolia Broadleaf Arrowhead S5 G5 L4 Schoenoplectus tabernaemontani Soft-stem Bulrush S5 G5 L4 Sparganium eurycarpum Large Bur-reed S5 G5 L3 Typha latifolia Broad-leaf Cattail S5 G5 L4 Viburnum trilobum High-bush Cranberry S5 G5T5 L2 Site Condition and Disturbances Most of this natural area is early successional. The domination of Hawthorn in five communities is indicative of livestock grazing (historical or current). The use of the north part of the area by off-road vehicles has created significant disturbance to the large meadow communities. The unauthorized tracks and trails caused by these vehicles (on public lands) may disturb or destroy vegetation communities and wildlife habitat and contributes to erosion. Flooding affects most of the riparian communities. Flooding is predominantly moderate to severe along the upper two-thirds of this area and is reduced farther downstream where the stream is in a more defined valley. Flooding is a natural phenomenon in valley-bottom communities but here it is exacerbated by the surrounding built environment, with reduced permeability. Trash is minimal and restricted to riparian communities. Several areas have been disturbed by earth filling, associated with the highway embankment in one part of the site and with the various industrial facilities in other parts of the site. All communities are to some extent disturbed by the presence of exotic species. Exotic species are more localized and less invasive in communities along the tributary creek, producing light disturbance levels. Several communities along Spring Creek are dominated by invasive species (e.g. Purple Loosestrife Mineral Meadow Marsh), where the highest levels of disturbance occur. The drier cultural communities (e.g. woodlands, savannahs, thickets, meadows) show mainly moderate disturbance with invasive species widespread throughout the communities. Highway 407 is busy and contributes noise and light-related disturbance.
DIXIE HIGHWAY 407 4 Ecological Features and Functions With wetlands over 0.5 ha in size and cultural meadow totalling over 10 ha, this natural area has the potential to support and sustain biodiversity, healthy ecosystem functions and to provide long-term resilience for the natural system. The riparian area provides a transitional zone between terrestrial and aquatic habitats, helping to maintain the water quality of the stream and serving as a species movement corridor. The creek itself serves as a species movement corridor. By containing a relatively wide variety of habitat types, this natural area supports biodiversity, particularly for species that require more than one habitat type for their life needs. While Highway 407 creates an impassable barrier for (land-based) wildlife movement to the north, the Spring Creek bridge provides for safe wildlife movement and connectivity is maintained upstream along the valley bottom to more natural areas north of the highway. The tributary stream flows through a small culvert under Highway 407, and therefore, wildlife connectivity along the small creek is not possible for terrestrial fauna (except birds). Reasonable connectivity downstream, along Spring Creek exists albeit across a busy road (Bramalea Road). The hydro corridor provides a broad eastwest corridor for wildlife movement, connecting Spring Creek to the valleys of other streams across agricultural lands both within and beyond the Etobicoke Creek watershed. The relatively close proximity of other areas of natural habitat creates above-average potential for wildlife movement between natural areas, species dispersal and recovery from disturbance, creating additional resilience for the ecosystem. Opportunities Off-road vehicle use of this area could be prevented by placing barriers to restrict access. This area occupies a key position at the intersection of two wildlife movement corridors (stream valley and hydro corridor) and thus connectivity with nearby natural areas should be maintained and enhanced where possible as it will facilitate species access to these movement corridors. Also, patches of tree cover, away from the hydro lines, could be developed by plantings to strengthen use of the hydro corridor by a variety of wildlife. However, the majority of the hydro corridor should be maintained as meadow or open habitat for area-sensitive grassland birds. Natural cover along the creek and tributary could be enhanced to facilitate increased use of the riparian zone as a species movement corridor. Delaying of grass-cutting or mowing of agricultural crops until after the young of ground-nesting grassland birds have fledged would benefit populations of these bird species. The distribution and extent of invasive species in this natural area could be monitored. Control of at least some invasive species might be considered. Given the extensive grassland habitat and decreased snow depths (due to heat from city and winds reducing snow cover), winter surveys of this area s use by raptors and small mammal surveys (summer) may be productive. Additional inventories of mammals, herpetofauna, dragonflies/damselflies and butterflies would help to fill knowledge gaps about this area. Literature Cited Bevers, C. 2010. Ontario Highways The History of the King s Highways and other Ontario Provincial Highways. Available at http://www.thekingshighway.ca/ Last Accessed 23 November 2010. Hicks, K. A. 2006. Malton: Farms to Flying. Friends of the Mississauga Library System, Mississauga, Ontario. Available at http://www.mississauga.ca/ Last Accessed 23 November 2010.
DIXIE HIGHWAY 407 5 Kaiser, Jeff. 2001. The Vascular Plant Flora of the Region of Peel and the Credit River Watershed. Prepared for: Credit Valley Conservation, the Regional Municipality of Peel, Toronto and Region Conservation Authority. Toronto and Region Conservation Authority. 2007. Terrestrial Natural Heritage Program Data Collection Methodology.
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