DIXIE - COURTNEYPARK 1 Region of Peel NAI Area # 3890, 3910, 3918, 4025, 4316, 4320, 4342 Toronto and Region Conservation Authority City of Mississauga Size: 49 hectares Watershed: Etobicoke Creek Con 4 E, Lots 6, 7; Con 5 E, Lots 6, 7 Subwatersheds: Lower Etobicoke Creek Ownership: 82% private, 18% public (City of Mississauga) General Summary This urban site consists of a section of vegetated Etobicoke Creek valley adjacent to the Toronto Pearson International Airport. It is comprised predominantly of cultural woodland and deciduous forest with the remainder of cultural meadow, cultural savannah and meadow marsh. The natural area is linear, riparian in focus and somewhat protected from human disturbance by virtue of being largely off-limits to the public. The area occupies a key position in maintaining a continuous vegetated corridor along Etobicoke Creek that allows wildlife movement. The area is undergoing succession from agricultural land use approximately 50 years ago and offers good habitat for grassland birds. 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). Currently, full species lists are not available however TRCA-tracked species and plant species that dominate vegetation communities are recorded here. Table 1: TRCA Field Visits Visit Date Inventory Type 29 Apr. 2003 Fauna 06 June 2003 Fauna 09 June 2003 Fauna 07 July 2003 Fauna 10 July 2003 Fauna 12 Aug. 2003 ELC, Flora 14 Aug. 2003 ELC, Flora Physical Features This area is in the South Slope physiographic region; characterized by low-lying ground moraines. Soils of this region tend to be clay loams with pore sizes between soil particles so small that flow of groundwater to aquifers is slow. Etobicoke Creek has eroded a valley into the plain. The creek is the main hydrological feature of this site, as the area consists of the vegetated floodplain and valley walls between dividing roads. The creek takes its natural course, meandering across the floodplain between the valley walls. Human History The former community of Mt. Charles was located to the northwest of this natural area, at the crossroads of Dixie Rd. and Derry Rd. Derry Rd. was once a busy pioneer road linking the villages of Malton and Meadowvale. In 1819, Charles King Sr. was granted 100 acres of dense forest on the northeast corner of this intersection. He later purchased 100 acres on the southeast corner of this intersection where he operated a store and where his son later ran a post office (Wilkinson, Undated). Mt. Charles provided basic services to the surrounding agricultural community. A condition on land granting at that time was that the recipient had to clear acreage of trees and establish agriculture on
DIXIE - COURTNEYPARK 2 the granted land. Thus clearing of the lands in the neighbourhood of this natural area likely began in the early 1800 s (earlier than farther north in the region). The former agricultural community of Elmbank was located to the southeast, at the former intersection of Torbram Rd (5 th Line) and Britannia Rd. E. The community was displaced by airport expansion. Toronto Pearson International Airport lies adjacent to the east side of this natural area. It is Canada s largest and busiest airport. It began as Malton Airport in 1939, a small airport on 420 acres of former farmland between Derry Rd., Elmbank Sdrd., Airport Rd. and Torbram Rd. The original airport was northeast of this natural area. In the 1950 s the land that includes this natural area was expropriated to expand the airport, which became Toronto International Airport in 1960 (later renamed Toronto Pearson International Airport) (Archdiocese of Toronto, Undated; Greater Toronto Airports Authority, 2007; Wilkinson, 2009; Wyle, Undated). From this we can gather that by 1939 land use in the area was primarily agricultural and that by the 1950 s it was no longer under cultivation. Noise-related disturbance would have steadily increased as air traffic increased and runways were built closer to the natural area. The part of this natural area that is on airport-owned land is closed to the public and as such receives no direct human disturbance (such as trails, trampling, trash etc.). Some airport service roads, narrower and much less busy than city streets, run between several treed parts of the area although they should impose only a minimal impediment to wildlife movement. Although part of this area is on land owned by the City of Mississauga, the property is not developed as a park so public usage is minimal. To the west, at the top of the valley slope, there is adjacent industrial land use. To the south, a road borders the natural area. A road also borders the area at its north end, but natural habitat is continuous under a bridge that spans Etobicoke Creek. Vegetation Communities The general community types present here are deciduous forest (6%), meadow marsh (2%), open aquatic (4%), cultural meadow (69%), cultural savannah (2%), cultural woodland (16%) and plantation (2%). Twenty-five plant communities were mapped for this area, comprised of 13 different vegetation types, none of which are provincially rare (Table 2). All of the deciduous forest and cultural woodland communities are young to mid-aged. Table 2: ELC Vegetation Communities Map reference * Vegetation type Size in hectares % of natural area FOD6-5 Fresh-Moist Sugar Maple - Hardwood Deciduous 0.49 1.00 Forest FOD7-3 Fresh-Moist Willow Lowland Deciduous Forest 1.18 2.41 FOD7-A Fresh-Moist Manitoba Maple Lowland Deciduous 0.83 1.69 Forest (2 communities) FOD8-1 Fresh-Moist Poplar Deciduous Forest 0.31 0.63 MAM2-2 Reed Canary Grass Mineral Meadow Marsh 0.8 1.62 (2 communities) OAO1 Open Aquatic Ecosite (deep or riverine) 1.99 4.04 CUM1-b Exotic Cool-season Grass Old Field Meadow 1.76 3.58 CUM1-C Exotic Forb Old Field Meadow (7 communities) 32.34 65.70 CUS1-B Exotic Cultural Savannah 0.75 1.53 CUW1-A3 Native Deciduous Cultural Woodland (2 communities) 1.27 2.58 CUW1-D Hawthorn Cultural Woodland (4 communities) 6.64 13.49
DIXIE - COURTNEYPARK 3 CUP1-4 Hybrid Poplar Deciduous Plantation 0.14 0.29 CUP1-7 Red (Green) Ash Deciduous Plantation 0.71 1.44 TOTAL AREA INVENTORIED 49.21 * 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. Species Presence Vascular Plants At least 51 species of vascular plants occur at this site, of which 36 (71%) are native. Two of these are regionally rare (Table 4). Five of the plant species present here are TRCA regional Species of Conservation Concern and an additional 12 are TRCA regional Species of Urban Conservation Concern (Table 4). Breeding Birds At least 14 species of breeding birds occur at this site, all of which are native. One of these, Bobolink (Dolichonyx oryzivorus), is Threatened nationally and provincially (Table 3). Three of the bird species are TRCA regional Species of Conservation Concern and an additional ten are TRCA regional Species of Urban Conservation Concern. Two colonial-nesting bird species, Northern Rough-winged Swallow (Stelgidopteryx serripennis) and Green Heron (Butorides virescens), occupy this site. Four grassland species, Bobolink, Savannah Sparrow (Passerculus sandwichensis), Eastern Kingbird (Tyrannus tyrannus) and Willow Flycatcher (Empidonax traillii), nest at this site; of which two (Bobolink and Savannah Sparrow) are areasensitive. Herpetofauna One herpetofaunal species, American Toad (Bufo americanus), was recorded as an incidental observation at this site. It is native and a TRCA regional Species of Urban Conservation Concern. Mammals At least one species of mammal occurs at this site, detected as an incidental observation. It is native and considered to be a TRCA regional Species of Urban Conservation Concern. Other mammal species are likely present but targeted inventories would be required to detect them. Table 3: Designated Species At Risk Scientific name Common name COSEWIC COSSARO S rank G rank BIRDS Dolichonyx oryzivorus Bobolink THR THR S4B G5 Table 4: 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 Acer saccharinum Silver Maple S5 G5 L4 Alnus incana ssp. rugosa Speckled Alder S5 G5T5 L3 Carpinus caroliniana American Hornbeam S5 G5 L4 Carya cordiformis Bitter-nut Hickory S5 G5 L4 Elymus riparius River Wild-rye S4? G5 L4 Fagus grandifolia American Beech S4 G5 L4 Iris versicolor Blue Flag S5 G5 L3
DIXIE - COURTNEYPARK 4 Physocarpus opulifolius Eastern Ninebark S5 G5 L3 Picea glauca White Spruce S5 G5 L3 Pinus strobus Eastern White Pine S5 G5 L4 Populus grandidentata Large-tooth Aspen S5 G5 L4 Rudbeckia hirta Black-eyed Susan S5 G5 L4 Schoenoplectus tabernaemontani Soft-stem Bulrush S5 G5 L4 Scirpus microcarpus Red-tinge Bulrush S5 G5 L4 Sparganium eurycarpum Large Bur-reed S5 G5 L3 Spiraea alba Narrow-leaved Meadowsweet S5 G5 L4 Thuja occidentalis Eastern White Cedar S5 G5 L4 BIRDS Scolopax minor American Woodcock S4B G5 L3 Ceryle alcyon Belted Kingfisher S4B G5 L4 Coccyzus erythropthalmus Black-billed Cuckoo S5B G5 L3 Dolichonyx oryzivorus Bobolink S4B G5 L3 Geothlypis trichas Common Yellowthroat S5B G5 L4 Tyrannus tyrannus Eastern Kingbird S5B G5 L4 Dumetella carolinensis Gray Catbird S5B G5 L4 Butorides virescens Green Heron S4B G5 L4 Colaptes auratus Northern Flicker S4B G5 L4 Northern Rough-winged Swallow S4B G5 L4 Stelgidopteryx serripennis Passerculus sandwichensis Savannah Sparrow S4B G5 L4 Actitis macularia Spotted Sandpiper S5B G5 L4 Empidonax traillii Willow Flycatcher S5B G5 L4 HERPETOFAUNA Bufo americanus American Toad S5 G5 L4 MAMMALS Odocoileus virginianus White-tailed Deer S5 G5 L4 Site Condition and Disturbances This urban natural area is unlike other urban areas in this report in that it is disturbed by industrial use (including an airport) rather than residential use. Natural areas with nearby residential use tend to be disturbed from recreational use. However, in this case, the industrial usage bars it from recreational use. Birds nesting in this area experience much greater levels of noise than those in other urban areas. However, some bird species can adapt to aircraft noise. TRCA compared bird diversity on the airport lands with that along the Etobicoke Creek valley between the airport and Lake Ontario. Bird diversity was in fact higher on the airport lands that were noisier and more historically disturbed, than it was in the intact natural areas away from the airport. It is believed that this difference is due to the closure of airport lands to the public and the resulting lack of direct human disturbance. It suggests both that local birds can adapt to airport noise and also that disturbances caused by the presence of people in natural areas may be underestimated (R. Krick, pers. comm., 2010). This site is regenerating from the historical loss of forest cover (over 150 years ago), and subsequent agricultural impacts. As such, young to mid-aged successional communities are represented.
DIXIE - COURTNEYPARK 5 Three of the woodland and forest communities have light to moderate logging disturbance. Communities along the Etobicoke Creek floodplain sustain light flooding. The maintenance of the natural river course with meanders helps to mitigate against flooding. Trash is generally light but is moderate and severe respectively in the two native deciduous cultural woodland communities from people dumping refuse out of sight over the valley edges. Light earth displacement is evident in two cultural woodland communities. Disturbance by exotics ranges from light to severe with moderate disturbance being the norm. Ecological Features and Functions With wetlands over 0.5 ha in size and extensive adjacent and included cultural meadows 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 river and providing a movement corridor for plants and wildlife. 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. The narrow, naturally vegetated valley of Etobicoke Creek extends both upstream and downstream from this site. Connectivity is generally good in this immediate area. Roads divide this from upstream and downstream areas but these roads terminate at the airport lands and are thus not as busy and dangerous for wildlife as other city roads are. Upstream, a bridge spanning the creek allows for continuous natural habitat under the bridge. 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. Etobicoke Creek runs through this area and thus this natural area supports the connectivity function of this watercourse and its tributaries by providing a natural habitat corridor that facilitates the crossregional movement of wildlife along this corridor between major provincial corridors. This natural area supports one bird Species At Risk and two regionally rare plant species. This site supports two colonial-nesting bird species and four grassland bird species of which two are area-sensitive. Based on the above features, this area should be evaluated to determine if significant wildlife habitat is present in accordance with the Provincial Policy Statement, Region of Peel Official Plan, and area municipal Official Plan. Opportunities Existing linkages to other natural areas upstream and downstream of this site should be maintained, as this area occupies a key position in providing a vegetated and natural corridor that promotes wildlife movement along the south part of Etobicoke Creek. While a variety of ways to increase the suitability of this area for wildlife, and to increase biodiversity and species abundances could be suggested, it is also important to keep in mind that increased wildlife use of this area could run counter to the safe operation of the airport. Concerns already exist about adjacent land uses that may increase wildlife (especially bird) activity and wildlife collisions with planes that would endanger air traffic. Additional inventories of herpetofauna, dragonflies/damselflies, butterflies and mammals may be productive given the presence of the river and habitat types both in this area and adjacent to it.
DIXIE - COURTNEYPARK 6 Literature Cited Archdiocese of Toronto. Undated. The Elmbank/Fifth Line Mission History. Available at http://www.archtoronto.org/ Last Accessed 23 November 2010. Greater Toronto Airports Authority. 2007. Toronto Pearson Today. Available at http://gtaa.com Last Accessed 6 April 6, 2011. 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. Wilkinson, M. Undated. Preserving Our Places. Available at http://www.oocities.com/judydrysdale/kinghistory.html Last Accessed 23 November 2010. Wilkinson, M. 2009. The Lost Village of Elmbank. Available at http://heritagemississauga.com Last Accessed 23 November 2010. Wyle. Undated. Noise Basics and the Effect of Aviation Noise on the Environment. Available at http://www.wyle.com/ Last Accessed 16 December 2010.
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