Credit River Coastal Marshes - Peel; Region · CREDIT RIVER COASTAL MARSHES Date of this Site...

CREDIT RIVER COASTAL MARSHES

Date of this Site Summary: July 2012

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Region of Peel NAI Area # 3255, 3274,

3276, 3291, 3296, 3297, 3301, 3304, 3317, 3327, 3329, 3330, 3341, 3342, 3344, 3345, 3346, 3348, 3364, 3375, 4128, 4129

Credit Valley Conservation Authority

City of Mississauga Size: 164 hectares Watershed: Credit River Range 1 CIR, Lots 6-7; Range 2 CIR, Lots 3-8; Range 3 CIR, Lots 3,4,

9, A-H, Mill Block, Indian Village;

Range 1 SDS, Lots 3-7; Range 2 SDS, Lots 3-9

Ownership: 82% private, 18% public

(Credit Valley Conservation, City of

Mississauga)

Subwatershed: Credit River: Norval to Port

Credit

General Summary This natural area is comprised of riparian vegetation communities and steep valley walls along the Credit River. They are summarized here also includes the many small vegetated patches between golf fairways and several islands in the river (hence the large number of NAI area numbers). This is a large, linear natural area, especially for an urban setting. This area is part of a major species movement corridor along the Credit River. It supports high biodiversity, particularly is rich in reptiles and amphibians including three Species At Risk herpetofauna. The area supports several other provincially and regionally rare species and a relatively high number of species of colonial-nesting birds. The quality of this natural area is reflected in its inclusion in two ANSI’s, three ESA’s and a provincially significant wetland. Where riparian vegetation exists, it provides a buffer from contaminated run-off and reduces erosion and siltation. Much of this natural area is a floodplain which provides flood water storage during peak flows. Groundwater seepage from the valley walls feeds into the Credit River. The area is highly fragmented however by developments on the floodplain. 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 over 79% of the delineated area by consultants for the Mississauga Natural Areas Survey (NAS). 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 data that this summary draws upon comes from inventories conducted by the MNR and several individuals. Fish species were inventoried both within the natural area and from upstream and downstream sampling stations (Table 1). As there are no barriers between the upstream station and this natural area, and between the downstream station and this natural area, the data from the upstream and downstream sites was extrapolated to this area and combined with data collected on-site. Table 1: CVC Field Visits Visit Date Inventory Type 06 July 2000 Fish 13 Aug. 2003 Fish 09 June 2005 Fish

09 Aug. 2005 Fish 16 July 2006 Fish 07 Sept. 2010 Flora



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Natural Feature Classifications and Planning Areas This natural area is part of: Life Science ANSI - regionally significant Credit River Coastal Marsh and regionally significant Credit River At Erindale ESA - Stavebank Oakwoods ESA and Credit River – QEW to CNR ESA PSW - Credit River Marshes Wetland Complex Physical Features This area is in the Iroquois Plain physiographic region; characterized by a gentle slope toward Lake Ontario and a thin layer of sandy and silty sand soils. The shoreline of glacial Lake Iroquois was higher than the current Lake Ontario shoreline and this area is old lake bottom. The Credit River is the main feature of this natural area, flowing the length of the area. The river has carved a deep valley into the surrounding tableland and winds back and forth across a broad floodplain in the valley bottom. Several small streams join the Credit River along its length in this natural area. Loyalist Creek joins from the west near the upstream end and Wolfedale and Shardawn Creeks join the Credit from the east near the mid-section of this natural area. Upon the arrival of Europeans (see below), the Credit River was a deeper and wider river than what it is now. At the time of European arrival, large ships were able to move upstream as far as this natural area. However, major deforestation resulted in increased erosion and evaporation and the Credit River is shallower today (Regional Municipality of Peel, 2002). Human History The area of the City of Mississauga was once the home of Mississauga First Nation. In the 1720’s French fur traders traded with the Misssissaugas and by 1798 the English had also established trade. After land treaties were signed between the Mississauga FN and the Crown in the early 1800’s, the Mississaugas relocated to a village site within this natural area in 1826. Between 1826 and 1847 the villagers cleared land for farming, built log cabins, a sawmill, a school and a Methodist chapel. In 1847, the Mississaugas moved to Hagersville, Ontario and the land became occupied by European settlers. Most or all of the floodplain of this natural area was then farmed. In 1906 part of it became what is now the Mississaugua Golf & Country Club (Anonymous, 2009; City of Mississuaga, 1995-2011; Mississauga Golf and Country Club, 2000-2007; Wilkinson, 2009). The steep valley walls of this area are naturally vegetated. Part of the valley bottom is also natural lowland forest or marsh however part of the floodplain is developed as two golf courses. All of the surrounding tablelands are in single-unit residential use as well as transportation corridors. Vegetation Communities A good portion of the vegetation community mapping generated by the Mississauga NAS coincides with this natural area as delineated here, although there are some 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. On the valley bottom, in the golf course there are many small patches of natural vegetation between fairways. The NAS mapping subsumes all of these and the golf fairways as a large “golf course“ land use whereas here, we have excluded the golf course fairways and treat the small natural patches between them as not yet covered by ELC. There are also some valley slope forest communities on the east side of the Credit River, near the southern end of the natural area that were subsumed into a large urban forest community type by the NAS. Here the built areas have been excluded from the natural area and the forest communities on the valley walls are treated as not yet coverage by ELC field work. The Vegetation Communities map following this text illustrates the discrepancies. Values for community



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size are taken from the NAS mapping whereas the overall size of this natural area is taken from the area delineation. The general community types present are deciduous forest (65%), shallow marsh (5%) and mixed shallow aquatic (9%). A total of 16 vegetation communities of five different types were mapped by the NAS for the 79% of this area that received ELC field work (Table 2). Seven communities were only classified to ecosite level. Some of the forest communities are mature, with trees generally 60-100 years old. There are also pockets of old growth, with tree ages exceeding 100 years. Some oaks are over 1 meter in diameter. Table 2: ELC Vegetation Communities Map reference *

Vegetation type Size in hectares

% of natural area

FOD3-1 Dry-Fresh Poplar Deciduous Forest 2.73 1.66

FOD5 Dry-Fresh Sugar Maple Deciduous Forest Ecosite (7 communities) 54.37 33.15

FOD7-3 Fresh-Moist Willow Lowland Deciduous Forest (2 communities) 49.79 30.36

MAS2-1 Cattail Mineral Shallow Marsh (4 communities) 7.44 4.54 SAM1-4 Pondweed Mixed Shallow Aquatic (2 communities) 15.47 9.43 TOTAL AREA INVENTORIED 129.80

* 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 313 vascular plant species have been recorded for this area, of which 201 (64%) 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). Stiff Goldenrod (Solidago rigida ssp. rigida, S-rank S3), a provincially rare species, was found growing amongst other prairie plants (Cecile, 2010). It is a new species for the Credit River watershed. Dark Mullein (Verbascum nigrum), an exotic species, was found here and is a new species for the Credit River watershed and Peel Region. Thirty-two vascular plant species are regionally rare (Table 4). Birds A total of 73 species of birds are recorded of this area, of which 69 (95%) are native. Some migrants and visitors were noted but most of the recorded bird species are believed to be breeding on site. This area is a migratory stop-over point for birds travelling along the Credit River corridor. Two of the visiting species were the nationally and provincially Threatened Chimney Swift (Chaetura pelagica), and the provincially rare Great Egret (Ardea alba) (S-rank S2B). One of the resident bird species present here, Barn Swallow (Hirundo rustica), is Threatened nationally. The provincially rare Black-crowned Night-heron (Nycticorax nycticorax; S-rank S3B, S3N) was also observed. This area supports six species of colonial-nesting birds, namely Great Blue Heron (Ardea herodias), Black-crowned Night Heron, Common Tern (Sterna hirundo), Northern Rough-winged Swallow (Stelgidopteryx serripennis), Bank Swallow (Riparia riparia) and Barn Swallow. Swallows are believed to nest in holes in the valley wall. This area supports five species of waterfowl, namely, Wood Duck (Aix sponsa), Gadwall (Anas strepera), Common Merganser (Mergus merganser), Blue-winged Teal (Anas discors) and Mallard (Anas platyrhynchos). It supports two species of wetland nesting birds, American Bittern (Botaurus lentiginosus) and Virginia Rail (Rallus limicola). Forest habitat supports



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four species of area-sensitive forest interior birds, Hairy Woodpecker (Picoides villosus), Pileated Woodpecker (Dryocopus pileatus), Winter Wren (Troglodytes troglodytes) and Red-breasted Nuthatch (Sitta canadensis). Open and successional habitat supports one species of grassland bird, Eastern Kingbird (Tyrannus tyrannus). The area also supports at least two species of raptor, Osprey (Pandion haliaetus ) and Sharp-shinned Hawk (Accipiter striatus). Fish A total of 28 species of fish are recorded for this area, of which 23 (82%) are native. An additional 15 species are known historically (from 1984), including the American Eel (Anguilla rostrata) (designated Special Concern nationally, Endangered provincially). This natural area supports warmwater fish communities. Herpetofauna A total of 11 herpetofaunal species are recorded as incidental observations from this site, of which ten (91%) are native. Two of these are Species At Risk, Eastern Snapping Turtle (Chelydra serpentina), and Northern Map Turtle (Graptemys geographica; Table 3). Both species are designated Special Concern nationally and provincially and are also provincially rare (S-rank S3). A 2002 record of Northern Map Turtle adults and a juvenile suggests breeding here or nearby. Other records include two snake species, 2 turtle species one of which is non-native, four frog species, one of which is Bullfrog (Rana catesbeiana), toad juveniles indicating breeding in this area and a salamander species. Historic records exist of Eastern Milksnake (Lampropeltis triangulum triangulum) (1935), Gray Treefrog (Hyla versicolor) (1939), Mudpuppy (Necturus maculosus) (1931), Northern Ringneck Snake (Diadophis punctatus; pre-1979), Smooth Green Snake (Opheodrys vernalis; from 1943), and Western Chorus Frog (Pseudacris triseriata; from 1943) (City of Mississauga, 2008; Ecologistics Limited, 1979). Mammals Nine native, common mammal species were detected here as incidental observations. This includes an unknown bat species. 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 BIRDS Hirundo rustica Barn Swallow THR S5B G5 Chaetura pelagica Chimney Swift THR THR S4B G5 HERPETOFAUNA

Chelydra serpentina Eastern Snapping Turtle SC SC S3 G5T5

Graptemys geographica Northern Map Turtle SC SC S3 G5

Table 4: Regionally Rare Vascular Plant Species (Kaiser, 2001) Scientific name Common name S rank G rank VASCULAR PLANTS Andropogon gerardii Big Bluestem S4 G5 Anemone cylindrica Long-fruited Anemone S4 G5



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Angelica atropurpurea Great Angelica S5 G5 Apios americana American Groundnut S5 G5 Bolboschoenus fluviatilis River Bulrush S4S5 G5 Campanula rotundifolia American Harebell S5 G5 Carex atherodes Awned Sedge S4S5 G5 Carex cephaloidea Thinleaf Sedge S5 G5 Carex digitalis Slender Wood Sedge S4S5 G5 Comandra umbellata Umbellate Bastard Toad-flax S5 G5 Elymus riparius River Wild-rye S4? G5 Epilobium coloratum Purple-leaf Willow-herb S5 G5 Galium boreale Northern Bedstraw S5 G5 Heracleum lanatum Cow-parsnip S5 G5 Heteranthera dubia Grassleaf Mud-plantain S5 G5 Lespedeza capitata Round-head Bush-clover S4 G5 Penstemon hirsutus Hairy Beardtongue S4 G4 Pilea fontana Springs Clearweed S4 G5 Potamogeton foliosus Leafy Pondweed S5 G5 Potamogeton richardsonii Redhead Pondweed S5 G5 Potamogeton zosteriformis Flatstem Pondweed S5 G5 Quercus velutina Black Oak S4 G5 Salix nigra Black Willow S4? G5 Schizachyrium scoparium Little Bluestem S4 G5 Schoenoplectus acutus Hard-stem Bulrush S5 G5 Sorghastrum nutans Yellow Indian-grass S4 G5 Stachys palustris Marsh Hedge-nettle SNA G5 Symphyotrichum oolentangiense Sky-blue Aster S4 G5 Symphyotrichum urophyllum Arrow-leaved Aster S4 G4G5 Taenidia integerrima Yellow Pimpernel S4 G5 Teucrium canadense ssp. canadense Canada Germander S5? G5T5 Vaccinium pallidum Early Lowbush Blueberry S4 G5

Site Condition and Disturbances This area is impacted by the urban environment in several ways. The two golf courses built on the floodplain have resulted in the removal of most of the natural vegetation of the floodplain in this section of the area. Not only do the golf courses disrupt the flow of species along the river and valley corridor, restricting their movement to narrow ribbons of vegetation along the course margins, but the ability of the floodplain to function ecologically as it would in the natural state, is compromised. Non-native species account for 36% of the vascular plant species in this natural area. Problematic invasive species present here are Norway Maple (Acer platanoides), Manitoba Maple (Acer negundo), Garlic Mustard (Alliaria petiolata), Dame’s Rocket (Hesperis matronalis), Common Reed (Phragmites australis), Colt’s-foot (Tussilago farfara), Japanese Knotweed (Polygonum cuspidatum), Black Locust (Robinia pseudo-acacia) and Common Lilac (Syringa vulgaris). Erosion along the valley walls is evident. Noise is extensive from surrounding residences, the golf courses, nearby roads and the QEW.



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Ecological Features and Functions The south part of this natural area contains all of the regionally significant Credit River Coastal Marsh Life Science ANSI. This same south portion of the natural area also contains all of the Stavebank Oakwoods ESA (valley related), all of the Credit River – QEW to CNR ESA (valley related) and all of the provincially significant Credit River Marshes Wetland Complex. The north part of this natural area falls into a portion of the regionally significant Credit River At Erindale Life Science ANSI and also forms most of the Credit River At Erindale ESA (valley related). The mid-portion of this natural area is not included in any designated ANSI, ESA or PSW. With forest communities greater than 2 ha and wetlands over 0.5 ha in size, 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. Natural habitat along the floodplain of the valley bottom has been interrupted by golf course developments in this area. However the steep valley walls remain in natural vegetation and thus provide continuity of habitat that allows the area to function as an important wildlife movement corridor. The valley carved by the river is deep enough that roads bridging it are carried by high bridges, such that natural communities are continuous under many of the road crossings. For short distances there are also linkages along the small valleys of Loyalist Creek, Wolfedale Creek, Shardawn Creek, Kenollie Creek and Mary Fix Creek. The large meadow natural area of the old Sheridan Landfill Site (Erin Mills – Dundas South, NAI # 187, 4870) is a short distance away from the upper end of this natural area, connected via the lower valley of Loyalist Creek. 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. The Credit River runs through this area 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. The Lake Ontario shoreline is also less than 2 km away, and this natural area thus supports regional connectivity along the Lake Ontario shoreline corridor. This area contains seeps. This area supports five Species At Risk (one plant species, two bird species, two turtle species, one snake species). Also, the area provides habitat for six provincially rare species (two plant species, two bird species, two turtle species) and 32 regionally rare plant species. This area supports six species of colonial-nesting birds, four species of area-sensitive forest interior birds, one grassland bird species and two raptor species. The waterway and wetlands of this area provide habitat for five species of waterfowl and two species of wetland nesting birds. This area supports Bullfrogs. This area supports turtle breeding. Wetlands of this area support amphibian breeding. 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.



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Opportunities Vegetation communities are expected to support butterflies and dragonflies/damselflies and a targeted survey should be performed. Landowners are encouraged to strengthen riparian corridors by widening the vegetated ‘ribbon’ along both banks of the Credit and be allowing native shrubs and trees to regenerate within this riparian zone. This regeneration could be accelerated through plantings. On the publicly-owned parts of this area, mapping and monitoring of invasive species and controls where possible could provide a starting point for establishing some control of invasive species in this area and also a place for demonstrating and educating the public about invasive species issues. Bats of undetermined species are present. Target audio inventories for this area would be able to determine which species are present. This natural area contains one forest with mature and old growth trees and should be checked for old-growth forest characteristics. Although vegetation communities have been inventoried here, the classification system used is not aligned with the system used elsewhere in the study area. At some point conducting field work to enable classification of communities using the ELC system provided by MNR would allow comparisons of communities in this area (and the rest of Mississauga) with the rest of the watershed and region. Literature Cited Anonymous. 2009. History of Port Credit. Heritage Mississauga. Available at http://www.heritagemississauga.com/ Last Accessed 28 April, 2010. Cecile, C. 2010. Creditview Marshes Flora Survey. Unpublished. City of Mississauga. 1995-2011. First Nations Gallery. Available at http://www.mississauga.ca/ Last Accessed April 28, 2010. City of Mississauga. 2008. Natural Areas Survey Database. Ecologistics Limited. 1979. Credit River Watershed, Environmentally Significant Areas. Credit Valley Conservation Authority, Mississauga. vi + 207 pp. Kaiser, J. 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. Mississaugua Golf and Country Club. 2000-2007. History of the Club. Available at http://www.mississauguagolf.com/ Last Accessed April 29, 2010. Regional Municipality of Peel. 2002. The Peel Water Story: A Water Curriculum Resource for Peel Schools. Regional Municipality of Peel, Brampton, ON. Wilkinson, M. 2009. History of Credit Mission. Heritage Mississauga. Available at http://www.heritagemississauga.com/ Last Accessed 28 April, 2010.



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Credit River Coastal Marshes - Peel; Region · CREDIT RIVER COASTAL MARSHES Date of this Site...

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