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SIXTH LINE - HIGHWAY 7 1 Region of Halton NAI Area # 7409 Credit Valley Conservation Authority Town of Halton Hills Size: 202 hectares Watershed: Credit River Con 7, Lots 23-27 Ownership: 92% private, 8% public (Town of Halton Hills) Subwatersheds: Black Creek; Silver Creek General Summary This large natural area is minimally disturbed and is in good condition. The area is comprised of deciduous and mixed forest and swamp with some marsh, with escarpment bedrock exposures visible throughout the area. Silver Creek and Black Creek have tributaries in this area. This area has good connectivity with other natural areas in adjacent concession blocks. This area is biologically rich, providing habitat for several Species At Risk as well as provincially and regionally rare species. Topographical and habitat variation contribute to this area s richness. NAI ELC surveyors inventoried vegetation communities and made incidental observation of flora and fauna (Table 1), covering 53% of the natural area (determined by access permission). Botanical, breeding bird, butterfly, dragonfly/damselfly and herpetofaunal inventories were conducted in 2003 and 2004 by Halton Natural Areas Inventory (HNAI) biologists using a methodology similar to that of this NAI, although their delineation of this natural area extended over more than one concession block. Hence, some of the species listed for this natural area, derived from the HNAI data, may only be present in adjacent habitat patches. Data from the Halton Natural Areas Inventory surveys is included in the NAI data set. Additional incidental records were contributed by other observers. This combined body of knowledge about this natural area is presented here. With respect to the NAI core inventories (vegetation communities, plants, breeding birds), this area is considered data-complete. Fish species were inventoried from both within the natural area and from upstream and downstream sampling stations. As there are no barriers between the upstream station and the natural area, and between the downstream station and the natural area, the data from these stations was extrapolated to the natural area and combined with on-site data. Table 1: NAI Field Visits Visit Date Inventory Type 08 Aug. 1989 Fish 23 Sept. 1996 Fish 25 Aug. 2008 ELC 26 Aug. 2008 ELC 27 Aug. 2008 ELC 28 Aug. 2008 ELC 29 Aug. 2008 ELC 02 Sept. 2008 ELC 04 Sept. 2008 ELC 10 Sept. 2008 ELC 16 July 2009 Fish Natural Feature Classifications and Planning Areas This natural area is part of: ESA - Waterfall Woods ESA PSW - Acton-Silver Creek Wetland Complex Niagara Escarpment Plan Greenbelt Plan Physical Features This area is in the Niagara Escarpment physiographic region; characterized by an escarpment that forms a significant break in the bedrock of the region. The escarpment has formed from the differing erosion rates of the bedrock layers, the softer lower shale layers eroding out from under the hard

SIXTH LINE - HIGHWAY 7 2 dolostone cap rock until portions of the cap rock collapse to form a cliff face and talus slope. In this area, the escarpment cliff feature is largely buried by glacial deposits, producing a sudden rise in the land rather than a cliff face. Most of this area drains into Black Creek, but the northern tip of the area drains into Silver Creek. Black Creek and Silver Creek join together in Georgetown and then in turn, flow into the Credit River at Norval. Human History The nearest community, Limehouse, is located about 2 kilometres southwest and was settled around 1820. This natural area is bordered by Sixth Line on the west side, Highway 7 [Queen St. (Acton)] to the north, Trafalgar Rd. to the east and 22 Sideroad on the south side. Large parts of this natural area extend to these roads although the extensions are interrupted by residential clearings. Surrounding land use is predominantly agricultural with some rural residential and rural estate, some regenerating cleared land, and a gravel pit. A large man-made pond on a rural estate flanks part of the west side of this natural area. The edge of urban development of Georgetown is just over 2 km east of this natural area. Although the core of this natural area remains intact, the margins of the area have been fragmented by residential clearings. Vegetation Communities The general community types present are coniferous forest (4%), deciduous forest (38%), mixed forest (13%), marsh (5%), coniferous swamp (3%), deciduous swamp (6%), mixed swamp (14%), thicket swamp (1%), open aquatic (<1%), cultural meadow (4%), cultural thicket (1%), cultural savannah (2%), cultural woodland (6%) and plantation (4%). A total of 39 vegetation communities of 25 different types were mapped over the 53% of this area to which the NAI ELC crew had access (Table 2). Two vegetation types, Dry-Fresh White Pine Sugar Maple Mixed Forest (FOM2-2) and Fresh-Moist Sugar Maple Hemlock Mixed Forest (FOM6-1, 2 communities) are regionally rare. The Black Ash Mineral Deciduous Swamp (SWD2-1) community has an inclusion of provincially rare White Cedar Conifer Mineral Coniferous Swamp (SWC1-2, S- rank S3S4). Table 2: ELC Vegetation Communities Map reference * Vegetation type Size in hectares % of natural area FOD4-2 Dry-Fresh White Ash Deciduous Forest 2.33 1.16 FOD5-1 Dry-Fresh Sugar Maple Deciduous Forest 3.39 1.68 FOD5-3 Dry-Fresh Sugar Maple Oak Deciduous Forest 1.60 0.79 FOD5-4 Dry-Fresh Sugar Maple Ironwood Deciduous Forest 3.10 1.53 Dry-Fresh Sugar Maple White Ash Deciduous FOD5-8 Forest (5 communities) 16.27 8.05 Fresh-Moist Sugar Maple Hardwood Deciduous FOD6-5 Forest 1.68 0.83 FOD8-1 Fresh-Moist Poplar Deciduous Forest 0.67 0.33 Dry Fresh Sugar Maple Hardwood Deciduous Forest (4 communities) 32.73 16.20 FODM5-11 FOM2-2 Dry-Fresh White Pine Sugar Maple Mixed Forest 3.26 1.61 FOM3-1 Dry-Fresh Hardwood Hemlock Mixed Forest 1.19 0.59 FOM3-2 Dry-Fresh Hemlock Sugar Maple Mixed Forest 1.90 0.94

SIXTH LINE - HIGHWAY 7 3 FOM6-1 Fresh-Moist Sugar Maple Hemlock Mixed Forest (2 communities) 3.14 1.55 MAM2-2 Reed-canary Grass Mineral Meadow Marsh 0.57 0.28 MAM2-9 Jewelweed Mineral Meadow Marsh 0.91 0.45 MAMM2-6 Joe Pye Weed Forb Mineral Meadow Marsh 0.81 0.40 Broad-leaved Cattail Mineral Shallow Marsh MAS2-1A (2 communities) 3.07 1.52 MAS2-D Reed Canary Grass Mineral Shallow Marsh 0.69 0.34 SWD2-1 Black Ash Mineral Deciduous Swamp 3.46 1.71 SWD2-2 Red (Green) Ash Mineral Deciduous Swamp 1.34 0.66 SWD3-1 Red Maple Mineral Deciduous Swamp (2 communities) 1.79 0.89 SWD3-2 Silver Maple Mineral Deciduous Swamp 2.71 1.34 SWM1-1 White Cedar Hardwood Mineral Mixed Swamp (2 communities) 3.35 1.66 SWM2-1 Red Maple Conifer Mineral Mixed Swamp (2 communities) 3.42 1.69 White Cedar Hardwood Organic Mixed Swamp (2 communities) 6.29 3.11 SWM4-1 SWMA-A Red (Green) Ash Hemlock Mineral Mixed Swamp 6.79 3.36 TOTAL AREA INVENTORIED 106.46 * 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 293 vascular plant species are recorded for this area, of which 230 (78%) are native. One of these is a Species At Risk (Table 3). Butternut (Juglans cinerea) is Endangered nationally and provincially, as well as being provincially rare (S-rank S3?). Of the nine Butternut trees documented, all but one were mature trees. Although all were cankered, three were less affected than the others. Hybrid Baneberry (Actaea x ludovici, S-rank S1?) and Cooper s Milkvetch (Astragalus neglectus, S- rank S3) are provincially rare. Five regionally rare vascular plant species were detected (Table 4). Breeding Birds A total of 63 species of birds are recorded, all of which are native. Most of these species showed some level (possible, probable, confirmed) of breeding evidence. One of these, Canada Warbler (Wilsonia canadensis), is Threatened nationally and Special Concern provincially (Table 3). This natural area supports one species of colonial-nesting bird, Green Heron (Butorides virescens). Interior forest habitat exists at this site, supporting eight species of area-sensitive forest interior birds, namely Hairy Woodpecker (Picoides villosus), Pileated Woodpecker (Dryocopus pileatus), Redbreasted Nuthatch (Sitta canadensis), Brown Creeper (Certhia americana), Winter Wren (Troglodytes troglodytes), Veery (Catharus fuscescens), Ovenbird (Seiurus aurocapilla) and Scarlet Tanager (Piranga olivacea). Fish A total of 17 species of fish were recorded, all of which are native. One of these, Redside Dace (Clinostomus elongates), is nationally and provincially Endangered (Table 3). Redside Dace is also provincially rare (S-rank S2). Adults and young of the year were observed for both Creek Chub (Semotilus atromaculatus) and White Sucker (Catostomus commersonii). Pearl Dace (Margariscus margarita) occurs at this site, one of only a few locations where this species has been detected in the Credit River watershed. This natural area supports coldwater fish communities.

SIXTH LINE - HIGHWAY 7 4 Butterflies and Skippers A total of 18 butterflies/skippers were recorded as incidental observations, of which 16 (88%) are native. Dragonflies and Damselflies A total of 12 dragonflies/damselflies were recorded as incidental observations, all of which are native. Two of these, Swamp Spreadwing (Lestes vigilax) and Sweetflag Spreadwing (Lestes forcipatus) are regionally rare in Halton Region (Dwyer, 2006). Herpetofauna Twelve herpetofaunal species occur here, recorded as incidental observations, all of which are native. Two of these, Eastern Snapping Turtle (Chelydra serpentina; reported by a landowner) and Eastern Milksnake (Lampropeltis triangulum triangulum) are designated Special Concern nationally and provincially (Table 3). Both species are also provincially rare (S-rank S3 for both). Two additional snake species, one salamander, an additional turtle species and six frog/toad species are present. Historic records (1987, 1986, 1979) exist for Smooth Green Snake (Opheodrys vernalis). A historic record of an Eastern Newt (Notophthalmus viridescens; pre-1990) was reported in Macadam (1999) either in or near this natural area. Mammals Ten native, common species of mammals were detected at this site as incidental observations. 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 Wilsonia canadensis Canada Warbler THR SC S4B G5 FISH Clinostomus elongatus Redside Dace END END S2 G4 HERPETOFAUNA Lampropeltis triangulum triangulum Chelydra serpentina Eastern Milksnake SC SC S3 G5T5 Eastern Snapping Turtle SC SC S3 G5T5 Table 4: Regionally Rare Vascular Plant Species (Kaiser, 2001) Scientific name Common name S rank G rank VASCULAR PLANTS Anemone cylindrical Long-fruited Anemone S4 G5 Astragalus neglectus Cooper's Milkvetch S3 G4 Botrychium dissectum Cutleaf Grape-fern S5 G5 Conopholis americana Squaw-root S4? G5 Lobelia cardinalis Cardinal Flower S5 G5

SIXTH LINE - HIGHWAY 7 5 Site Condition and Disturbances This large, relatively undisturbed, treed natural area is in good condition. However, it has been fragmented by clearings for rural residences and estates. Non-native species are minimal except in a forest area adjacent to a house where Goutweed (Aegopodium podagraria) and Periwinkle (Vinca minor), both garden species, have escaped. Other notable invasive species are Garlic Mustard (Alliaria petiolata) and Common Buckthorn (Rhamnus cathartica). Some trees appear to have suffered from ice damage and have lost limbs. Some (private) well marked trails are present which sustain light recreational use. These trails mostly pass through the drier forested areas. Noise is slight overall, but intense near Highway 7. Ecological Features and Functions Most of this area is part of Waterfall Woods ESA (wetland type). Part of this area is included in the provincially significant Acton-Silver Creek Wetland Complex. With forest communities greater than 4 ha, 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 areas provide 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. By containing a relatively high number of habitat types, this natural area has the potential for high biodiversity function, particularly for species that require more than one habitat type for their life needs. This natural area contains two regionally rare vegetation community types and thus has the potential to support additional biodiversity above and beyond that found in common community types. This area has connectivity with a natural area to the north across Highway 7. There is also good connectivity to the south across 22 Sideroad, along Black Creek, as well as fragmented connectivity across Sixth Line with a large natural area to the southwest. Several narrow linkages exist across Trafalgar Rd. with another large natural area to the northeast. 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. This area contains headwaters of Black Creek and Silver Creek, two major tributaries of the Credit River, and thus 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 contains two regionally rare vegetation types. This area supports five Species At Risk (one plant species, one bird species, one fish species, one turtle species, one snake species), six provincially rare species (three plant species, one fish species, one turtle species, one snake species) and five regionally rare plant species. Interior forest habitat is present in this area, supporting eight species of area-sensitive forest interior birds. One species of colonial-nesting bird is also present. Wetlands of this natural area support amphibian breeding. This area may support turtle breeding.

SIXTH LINE - HIGHWAY 7 6 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. Opportunities There is a potential for wildlife road mortality as this natural area is bordered by two busy roads (Highway 7 and Trafalgar Rd.). An assessment of the extent of wildlife road mortality may reveal if and where measures to mitigate against this mortality might be taken (constructed crossings and signage), may be warranted. The health of the Butternut trees present at this site could be assessed by a Butternut Assessor to determine whether any might be candidates for inclusion in the Butternut recovery program. This natural area contains four mature forest communities which could be checked for old-growth forest characteristics. Although this area is data-complete for the core NAI inventory types as well as for several other groups, in view of the size and biodiversity of this area, bat surveys might be productive. Literature Cited Dwyer, J. Halton Natural Areas Inventory. 2006. 2 volumes. Volume 1: Site Summaries. Volume 2: Species Checklists. ISBN 0-9732488-6-6, 0-9732488-7-4. Self-published. 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. Macadam, L. 1999. The Herpetofauna Atlas for the Halton Region. Halton/North Peel Naturalist Club, Georgetown, ON.

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