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St. Williams Crown Land contains several plant communities that are significant at the provincial (Bakowsky 1997) or regional level. A brief synopsis is provided for each community. Savanna Communities

Tallgrass Prairie, Savanna and Woodland communities are extremely rare in Ontario (Bakowsky 1997). Less than three percent of their original extent remains in southern Ontario and most remnants occur in small isolated patches (Rodger 1998). St. Williams Crown Land represents the largest and most species rich remnant of savanna habitat in southern Ontario outside the provincial parks system. Most of this habitat has been modified by forest management and is presently ingrown. Less than one ha was sufficiently open in 2001 to be classified as Black Oak - White Oak Tallgrass Woodland (Lee et al. 1998).

A first approximation of ingrown savanna at St. Williams is mapped in yellow in Figures 32 and 33. One or more conservative vascular plant indicators of tallgrass prairie and savanna in Ontario (Oldham et al. 1995, Rodger 1998) were recorded on drought-prone soils in each area during the period 1908-1945 or 1986-2001. Ingrown savanna has been partitioned in relation to six themes in order to highlight differences in species composition, community structure and land use history.

Black Oak - White Oak Tallgrass Woodland: This tiny remnant (0.15 ha) is the only surviving stand of natural tallgrass woodland at SWCL. It persists on moderately fresh sand soils on the crest and slopes of a dune ridge that was clear-cut between 1945 and 1953. Canopy closure approaches 60%. Conservative indicators of savanna conditions include Dwarf Chinquapin Oak (S2), Waxy Meadow Rue (S2), Wild Lupine (S3), Hairy Bedstraw (S3), Venus’-pride, Whorled Loosestrife, and Smooth Aster. Prominent herbs in the herb layer include Pennsylvania Sedge, Poison Ivy, Goldenrod, and Low Sweet Blueberry.

Cultural Savanna: Two small remnants of ingrown savanna were thinned to savanna conditions in 1991. These remnants were situated on fresh sand soils on the crest and slopes of dune ridges that were clear-cut between 1945 and 1955. The northern remnant was the location of the last sighting (1988) of the rare Karner Blue (COSEWIC Extirpated), Frosted Elfin (COSEWIC Extirpated) and Persius Duskywing butterflies (ELC polygon 87). The southern remnant, which was burned in 1994, harbors a nationally significant assemblage of Arthropod insects that is still being assessed (ELC polygon 85). Eighteen plant species with prairie/savanna affinities, including 13 conservative indicators of savanna conditions, were observed on the northern remnant in 2001 (Table 10).

Cultural Sand Barrens: Barrens are plant communities characterized by a variable array of herbs, shrubs and small stunted trees on drought-prone, infertile soils (Homoya 1994). Vegetation is typically sparse and patchy, with areas of bare or moss covered soil; tree cover may range to 60% canopy closure depending on site conditions and site history (Homoya 1994, Lee et al. 1998).

In this study, the phrase “sand barrens” is used to highlight areas of bare sand soils that are sparsely vegetated. At St. Williams, sand barrens are typically “cultural sand barrens” in the sense that bare soil conditions originated with some form of human disturbance, although sand barrens are also found in natural openings in ingrown oak savanna. At SWCL, cultural sand barrens appear to be transitional communities that will be displaced by treed communities in the absence of disturbance.

The most extensive cultural sand barrens are found in the northeast quadrant of the Manestar Tract. These lands were cleared between 1945 and 1953, and apparently bulldozed and selectively sand mined between 1955 and 1972. Prior to land clearance, these lands supported oak savanna or oak woodland.

Today, these barrens support one of the richest assemblages of plants with prairie/savanna affinities at SWCL. Eighteen species with prairie/savanna affinities, including 10 conservative indicators of savanna conditions occur on the grubbed sand dunes. Nineteen species with prairie/savanna affinities, including 11 conservative indicators of savanna conditions occur on lands that were mined for sand. Species not found elsewhere at SWCL are: Englemann’s Spikerush (S1), Sharp-fruited Rush (S3), Greene’s Rush (S3), Prairie Buttercup (S3), and Hairy Bush-clover. A rich diversity of insects has attracted the attention of the scientific community for many years. Eastern Hognose Snake (COSEWIC Threatened) is sighted regularly.

Communities with Abundant Dwarf Chinquapin Oak: Selected stands of ingrown savanna, and dune blow-outs, provide habitat for comparatively large populations of Dwarf Chinquapin Oak (S2). These stands represent Canada’s largest concentration of Dwarf Chinquapin Oak outside of Pinery Provincial Park (Cruise and Catling 1969). Dwarf Chinquapin Oak has a high fidelity for savanna communities (Coefficient of Conservatism: 10) and is associated with many of the richest assemblages of prairie/savanna plants on the Nursery and Manestar Tracts.

Ingrown Savanna: A small portion of original savanna habitat at St. Williams was left relatively undisturbed. In the absence of fire, these stands have succeeded to oak or oak-pine forest. Conservative indicators of savanna conditions still persist in canopy openings or at the forest edge. The highest quality remnants and richest assemblages of prairie/savanna species occur on the Manestar Tract (discussed above), and on Turkey Point Tract. Selected remnants at the Turkey Point Tract retain populations of Virginia Goat’s-rue (COSEWIC Endangered), Bird’s- foot Violet (COSEWIC Threatened), Britton’s Phlox (S1), Green Milkweed (S2), and Perfoliate Bellwort (S1).

Under-planted Savanna: Much of the original savanna habitat on the Nursery Tract was under- planted with conifers during the period 1908-1945. Selected stands on the periphery of conventional plantations at the Turkey Point Tract may also have been under-planted. Black Oak and defective or diseased trees were removed and sites spot-planted with conifer seedlings under a thinned canopy. These practices left the original herb layer, and associated natural values, largely intact. Many of these areas contained conservative indicators of savanna conditions when under-planted by forest station staff. A diverse assemblage of savanna species still persist in high light areas at the forest margin and along the edge of fire roads, especially where sand dunes are present. These lands represent the primary opportunity at SWCL for extensive rehabilitation and restoration of savanna communities.

Furrow-planted Savanna: Conventional conifer and hardwood plantations were established on lands previously cleared for agriculture. A diverse but diminished assemblage of plants with sand barren and prairie/savanna affinities persists in high light areas at the edge of plantations, along the edge of adjacent fire roads, and in the openings of thinned and young plantations. These plantations were often established on blow-sands following destruction of the root mat by 19th century agriculture. Stands at the Turkey Point Tract represent the primary opportunity for rehabilitation and restoration of the high light, sand barren/sand prairie phase of savanna development.

Wetland Communities

Swamp White Oak Mineral Deciduous Swamp (S3): This community (?0.5 ha) occurs on very moist sand soils in a wetland complex associated with Dedrick’s Creek. The leading canopy species are Swamp White Oak, Red Oak and Red Ash. Prominent trees and tall shrubs in the subcanopy include Red Ash, Nannyberry and Blue Beech. Prominent shrubs in the understorey include Gray Dogwood, Nannyberry, American Hazel and Choke Cherry. Prominent herbs in the ground layer include Northern Lady Fern, Sensitive Fern, Running Strawberry Bush, and Golden Ragwort.

Buttonbush Mineral Thicket Swamp (S3): This community (<0.2 ha) occurs on very moist sandy loam soils on the northern periphery of the Nursery Tract. Standing water is present in the spring. Prominent species in the herb layer include Marsh Fern, Rice Cut Grass, False Nettle and Water Smartweed.

Silky Dogwood Mineral Thicket Swamp (S3S4): This community occurs on moist to very moist sand, sandy loam and loamy sand soils on the Nursery Tract. The leading species in the shrub layer are Silky Dogwood, Riverbank Grape, Winterberry, High Bush Cranberry, Red-osier Dogwood, Pussy Willow or Bebb’s Willow. Prominent species in herb layer are False Nettle, Water-horehound, Rice Cut Grass, Jewelweed, Sensitive Fern, Canada Goldenrod, or Raspberry. Gray Dogwood Mineral Thicket Swamp Type (S3S4): This community occurs on moist sand soils on the Nursery Tract. The leading species in the shrub layer are Gray Dogwood, Red-osier

Dogwood, Nannyberry, Smooth Rose or Spicebush. Prominent species in the herb layer are Gray Dogwood, Riverbank Grape, Water-horehound, and False Nettle.

Communities with Abundant Black Gum: Selected hardwood stands on the Nursery Tract contain locally abundant stems of Black Gum (S3) in the subcanopy and sapling layers. The diameter breast height of sampled stems ranged to 54 cm. Fresh-Moist Oak - Maple Deciduous Forest stands with Black Gum occur on moist loamy sand soils, Swamp Maple Organic Deciduous Swamp with Black Gum occurs on very moist sandy loam organic soils. Small diameter stems of American Chestnut (COSEWIC Threatened) were also present.

Provincially Significant Wetlands: Portions of selected wetlands on the Nursery Tract have been classified as Class I (Bacro 1987, Umlah et al. 1996) and Class II (Umlah and Haggeman 1996) wetlands (labeled diagonal lines, Figure 32). Six wetlands form part of a large wetland complex on the northern periphery of the Nursery Tract, known as St. Williams. Eleven wetland ecosites and 23 wetland vegetation types are present in the St. Williams portion of this complex (Figure 22). Significant species in this complex are American Chestnut (COSEWIC Threatened), Stalked Water-horehound (S2), Pumpkin Ash (S2), Black Gum (S3), and Hairy Wood Lettuce (R1).

Wetlands associated with Mud Creek have been classified as Class II wetlands (Umlah and Haggeman 1996). Four wetland ecosites and eight vegetation types are present in the St. Williams portion of the wetland complex which extends to the east and south of the Nursery Tract. Silky Dogwood Thicket Swamp (S3S4) is present in this complex on the east side of Regional Road 16.

Genetic Archives, Experimental Plantations and Arboreta

Genetic archives, experimental plantations and arboreta have been established at the Turkey Point Tract by the OMNR.

Soft Pine and Spruce Archives: These archives contain identified collections of soft pine and spruce from around the world. The archives are used to maintain parent material in a state where controlled breeding is possible and are intended to be permanent plantations. A small population of Rough-fruited Panic Grass (S3) is present on bare sand soil at the edge of the archives, small populations of Bayberry (S1), Grass-leaved Rush (S2) and Hairy Pinweed (S3) are present. Experimental Plantations: Experimental plantations have been established throughout the Turkey Point Tract. Many of these plantations were established on blow-sand areas and in oak savanna. The only apparently native population of Forked Blue-curls (S1) in Canada was once widespread but now exists only in one spot.

Arboreta: Arboreta, composed of selected hardwood and conifer species, were established on former savanna lands and contain small populations of several prairie/savanna plants that are

provincially and regionally rare: Arrow-feather Three-Awn (S1, R1), Sun Sedge (S1, R1), Side- oats Gramma (S2, R2), Green Milkweed (S2, R3) and Grooved Yellow Flax (S3,R2).