COLLEGEWAY – BURNHAMTHORPE 1 (ROY IVORS WOODLOT)

Region of Peel NAI Area # 3267, 3293 Credit Valley Conservation Authority City of Size: 40 hectares Watershed: Credit River Range 1 NDS, Lots 1- Ownership: 8% private, Subwatershed: Sawmill 3; Range 2 NDS, Lots 92% public (City of Creek 1-3; Range 3 NDS, Mississauga) Lots 1-3

General Summary This natural area is large for an urban area and most notably it contains a forest patch sufficiently large enough to provide interior forest habitat. It is comprised of the remaining vegetated valley of Sawmill Creek, a tributary of the Credit River, as the creek runs through urban Mississauga. The area is bisected by a busy road. However, the area is in relatively good condition, supporting several Species At Risk and some provincially and regionally rare species. The flora tends to have a Carolinian character. Patches of mature forest exist here with some trees over 100 years old. The location of this area makes it important for migrating birds.

NAI botanists carried out a targeted search for plant species known historically from this site and also recorded incidental plant observations (Table 1). Other data has been compiled from a variety of sources. Vegetation communities, plant species and breeding birds were inventoried by consultants for the Mississauga Natural Areas Survey (NAS), covering 80% of the delineated area. The NAS surveys were conducted four times between 1996 and 2009. CVC’s Terrestrial Monitoring biologists have frequently and regularly visited a monitoring plot within this site from 2003 to the present. Their species observations from 2003 to 2009 are included in the data set reported on here (the CVC database is annually updated and thus will be the most current source at any point in time) although their data are restricted to the monitoring plot. Additional incidental records were contributed by other observers. Fish species were inventoried from upstream and downstream sampling stations. As there are no barriers between the upstream station and this natural area and between the downstream station and this area, the data collected were extrapolated to this area.

Table 1: CVC Field Visits Visit Date Inventory Type 16 Aug. 2004 Fish 17 June 2008 Fish 16 June 2006 Fish 16 June 2009 Fish 31 July 2007 Fish 19 Aug. 2010 Flora

Natural Feature Classifications and Planning Areas This natural area is part of: Life Science ANSI - provincially significant Roy Ivor’s Woodlot ESA - Roy Ivor’s Bird Sanctuary ESA

Physical Features This area is in the Iroquois Plain physiographic region; characterized by a gentle slope toward Lake and a thin layer of sandy and silty sand soils. The shoreline of glacial Lake Iroquois was higher than the current shoreline and this area was once an old lake bottom.

Two branches of Sawmill Creek pass through this natural area, one branch through each portion. The branches join at the south tip of this area and then join the Credit River a short distance downstream,

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just south of Dundas St W. The lower part of Sawmill Creek downstream of the union of the branches in this area is channelized and engineered.

Human History The nearby community of Erindale is located about one kilometre southeast on the Credit River near the intersection of Mississauga Rd. and Dundas St. W. It was first settled in the 1820’s when a saw mill, flour mill, church and post office were built. Erindale later had a dairy (Heritage Mississauga, 2009). From this we can infer that logging, crop-raising and livestock-raising were major land uses of the surrounding countryside.

Roy Ivor, an ornithologist, opened Windinglane Sanctuary for injured and sick birds within this natural area in 1928 and ran it for fifty years until his death in 1979. It was then taken over by his friend Bernice Inman-Emery who ran it until her death in 2009. Roy Ivor studied the character of birds and wrote many books about them. He was one of the first people to raise the alarm about the harmful effects of DDT in 1948 (Heritage Mississauga, 2009).

Most of this natural area is municipal parkland occupying the valley of Sawmill Creek and the valley of a smaller branch of the creek. The parklands have a network of well-marked trails that sustain heavy recreational use. The Collegeway (a road) runs along a ridge between the valleys, bisecting the natural area into two. In the upstream direction this area extends to Burnhamthorpe Rd. and in the downstream direction the valley extends to Mississauga Rd. Surrounding land use on the tableland is medium and high density residential and institutional.

This area plays an important role in providing urban residents with an aesthetic place for passive enjoyment of nature and the environment.

Vegetation Communities For the most part, the vegetation community mapping generated by the Mississauga NAS coincides with the NAI natural area delineations in Mississauga although there are some small discrepancies. Part of this could be due to real changes in community boundaries between the years that the mapping and area delineation were done. Other factors that may contribute to discrepancies are differing ways of defining edges of communities and differing levels of resolution in mapping. The Vegetation Communities map following this text illustrates the discrepancies. Values for community sizes and proportions making up the natural area are taken from the NAS mapping.

The general community types present are coniferous forest (15%), deciduous forest (28%), mixed forest (45%) and cultural meadow (11%).

A total of eight different vegetation communities, belonging to seven different vegetation types are present in this natural area (Mississauga NAS, 2006; Table 2).

Table 2: ELC Vegetation Communities Map Vegetation type Size in % of natural reference * hectares area FOC3-1 Fresh-Moist Hemlock Coniferous Forest 6.00 15.16 FOD5-2 Dry-Fresh Sugar Maple - Beech Deciduous Forest 2.28 5.76 Dry-Fresh Sugar Maple - White Ash Deciduous FOD5-8 Forest 1.86 4.69 FOD7-2 Fresh-Moist Ash Lowland Deciduous Forest 1.91 4.82 FOD7-3 Fresh-Moist Willow Lowland Deciduous Forest 5.08 12.83

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FOM3-2 Dry-Fresh Sugar Maple - Hemlock Mixed Forest 17.99 45.45 CUM1-1 Dry-Moist Old Field Meadow (2 communities) 4.47 11.29 TOTAL AREA INVENTORIED 39.59

* 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 A total of 232 vascular plant species are recorded for this area, of which 171 (74%) are native. One of these species, Butternut ( Juglans cinerea ), is Endangered both nationally and provincially, as well as being provincially rare (S-rank S3?; Table 3). Four additional vascular plant species are regionally rare (Table 4).

This site contains Carolinian species including Spicebush ( Lindera benzoin ), Blue-beech ( Carpinus caroliniana ), Shagbark Hickory ( Carya ovata ), American Witch-hazel ( Hamamelis virginiana ) and Climbing Poison Ivy ( Rhus radicans ssp. negundo ).

Birds A total of 41 species of breeding birds are recorded here, of which 39 (95%) are native.

Forest habitat at this site supports three species of area-sensitive interior forest breeding birds, namely, Hairy Woodpecker ( Picoides villosus ), Pileated Woodpecker ( Dryocopus pileatus ) and Red- breasted Nuthatch ( Sitta canadensis ). The area also supports one species of raptor, Sharp-shinned Hawk (Accipiter striatus ) and one species of waterfowl, Mallard ( Anas platyrhynchos ).

Fish Four fish species occur in this area, all of which are native. This natural area supports tolerant fish communities.

Butterflies and Skippers One species of native butterfly was recorded incidentally, the Monarch ( Danaus plexippus ), designated Special Concern both nationally and provincially (Table 3). Monarch is also provincially rare (S-rank S2N, S4B).

Herpetofauna Five herpetofaunal species were recorded here, all of which are native. These five species consist of a toad species, a salamander species and three snake species.

An historic collection of a Spotted Salamander (Ambystoma maculatum ) in 1972, a report of Bullfrog (Rana catesbeiana ) also in 1972, and a report of Western Chorus Frog ( Rana triseriata ) from 1973 were made at the nearby University of Toronto, Mississauga campus (Lamond, 1994). Historic records of Eastern Milksnake ( Lampropeltis triangulum triangulum ) (1932, 1935), Green Snake (Opheodrys vernalis ) (1932-by Roy Ivor), Bullfrog (1932), Gray Treefrog ( Hyla versicolor ) (1931), Spring Peeper ( Pseudacris crucifer ) (1931) and Northern Leopard Frog ( Rana pipiens ) (1926) were made at Erindale (Bull, 1938; Lamont, 1994).

Mammals Seven native, common mammal species were detected at this site.

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Table 3: Designated Species At Risk Scientific name Common name COSEWIC COSSARO S rank G rank VASCULAR PLANTS Juglans cinerea Butternut END END S3? G4

BUTTERFLIES S2N, Danaus plexippus Monarch SC SC S4B G5

Table 4: Regionally Rare Vascular Plant Species (Kaiser, 2001) Scientific name Common name S rank G rank VASCULAR PLANTS Elymus riparius River Wild-rye S4? G5 Leersia virginica White Grass S4 G5 Lindera benzoin Spicebush S5 G5 Muhlenbergia frondosa Wirestem Muhly S4 G5

Site Condition and Disturbances This area is impacted by the surrounding urban environment. Nevertheless, it is in relatively good condition. Since about 1980 this region has been urbanising. The area was severed in two sections by the building of The Collegeway road and some forested areas were cleared for road building and residential development. There is noise throughout this natural area from nearby residences and roads. These disturbances likely have led to a decrease in faunal diversity.

Non-native species are common and notable problematic invasive species present here are Garlic Mustard ( Alliaria petiolata ), Common Buckthorn (Rhamnus cathartica ), Dog-strangling Vine (Cynanchum rossicum ), Norway Maple ( Acer platanoides ) and Manitoba Maple ( Acer negundo ).

Tree diseases include Beech Bark disease, Nectria Canker (observed on a Sugar Maple) and Butternut Canker Disease.

There is a network of well-marked trails plus unauthorized side trails throughout the municipal park lands. The trails are well-used. The trails have and associated litter.

Ecological Features and Functions This natural area is included in Roy Ivor’s Bird Sanctuary ESA and the provincially significant Roy Ivor’s Woodlot Life Science ANSI. It is designated as a Significant Natural Site by the City of Mississauga (City of Mississauga, 2006).

With forest communities much greater than 2 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 creek and providing a movement corridor for plants and wildlife.

There are narrow linkages between the upstream and downstream ends of this natural area valley with other natural habitat up and down the valley, but the linkage passes over busy roads, which may limit movement of some species. An intermittent series of habitat patches link the lower part of this site with the main Credit River valley a short distance away. 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.

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Sawmill Creek flows through this area before meeting the Credit River less than a kilometre away and thus this natural area supports the connectivity function of the Credit River and its tributaries by providing a natural habitat corridor that facilitates the cross-regional movement of wildlife along this corridor between major provincial corridors.

This area contains vernal pools.

This area provides habitat for two Species At Risk (one plant species, one butterfly species).

This area supports two provincially rare species (one plant species, one butterfly species) and four regionally rare plant species.

Most of this natural area is composed of forest. These forest communities support three species of area-sensitive forest interior birds. The area also supports one raptor species and one waterfowl species.

The upland forest communities here have trees that are over 100 years old which may be old growth.

The location of this natural area, on a side valley near the Credit River, within 5 km of Lake Ontario, makes it an important stopover and staging area for migratory birds.

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.

Some of the plant species present here have Carolinian affinities.

Opportunities As most of this area is a municipal park, an opportunity exists to map, monitor and potentially control invasive species. Users of trails may serve as vectors for seeds of invasive species, spreading them deep into communities. Heavy use of trails increases the chance of introducing invasive species. The high use of this park presents an opportunity for educational messaging about invasive species issues as well as awareness-raising of the biological features of this area and other ecological issues.

Assessment of the health of the Butternut trees in this area by a Butternut Assessor would help determine whether any individuals would be candidates for inclusion in the Butternut recovery program.

With three species of snakes known from this natural area the possibility exists that they may hibernate on site. A spring search for snake hibernacula may be productive.

This natural area contains mature forest with some old growth trees. These mature forest communities could be checked for old-growth characteristics.

With mature trees and nearby water, this area may support bats. Audio bat inventories may help to better characterize the wildlife of this natural area.

Spring and fall surveys of the use of this area by migratory birds, bats and butterflies would help to understand its ecological functions.

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Literature Cited Bull, W.P. 1938. From Amphibians to Reptiles. Perkins Bull Foundation, Toronto, Ontario.

City of Mississauga. 2006. Natural Areas Fact Sheet Erin Mills EM4. Available at http://www.mississauga.ca/ Last Accessed 01 April, 2010.

Heritage Mississauga. 2009. Roy Ivor. Available at http://www.heritagemississauga.com/ Last Accessed 03 May, 2010.

Lamont, W. 1994. The Reptiles and Amphibians of the Hamilton Area . Hamilton Naturalist’s Club, Hamilton, ON.

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Date of this Site Summary: July 2012