Natural Heritage
Natural Heritage Overview
The St. Williams Conservation Reserve (SWCR) is in the heart of the Carolinian Life Zone in southwestern Ontario—Canada’s most biodiverse but also most threatened ecological region. Although this region occupies less than 1% of Canada’s land area, it is home to over 125 species at risk and approximately 400 provincially or globally rare species.
Located on the Norfolk Sand Plain—a remnant glacial lake delta—the landscape is characterized by well-formed sand dunes, particularly in the Nursery Tract, which are highly sensitive to erosion when vegetation is disturbed.
The SWCR supports a range of native ecological communities, including:
- Oak Savanna
- Oak Woodlands
- Tallgrass Prairies
- Sand Barrens
- Forests
- Wetlands and Streams
These ecosystems support one of the largest remaining oak savannas in Canada, a globally threatened habitat, and host over ninety provincially rare species of flora and fauna. SWCR is also internationally recognized as part of the UNESCO-designated Long Point World Biosphere Reserve.
The SWCR is actively managed to restore and maintain these native ecological communities.
Ecology, Importance of Oak Savanna & Sand Baren Habitat
SWCR is recognized at regional, provincial, national, and international levels for its biodiversity and ecological value. Oak savanna and sand barren habitats are critically important in southern Ontario. They support a rich diversity of plant and animal life, including many species at risk.
Oak savannas in particular, are home to specialized species that rely on open-canopy conditions and frequent disturbance. Sand barrens provide essential habitat for species that are adapted to dry, nutrient-poor, and fire-influenced environments, including Ghost tiger beetles, Eastern hognose snakes, and Whip-poor-wills.
Both the Oak savanna and sand barren habitats evolved with periodic fire, which helps maintain their open canopy and prevents succession into dense forest. Fire also promotes regeneration of fire-adapted species like Sundial lupine, New jersey tea, and Puccoon
The SWCR is dedicated to preserving and restoring its unique natural habitats. Management efforts focus on re-establishing native habitats, promoting natural succession, and safeguarding species at risk. This includes:
Restoring oak savannas and other tallgrass communities
Managing sand barrens to enhance ecological function
Conducting prescribed burns to maintain disturbance-dependent ecosystems
Managing plantations for ecological restoration
Through effective land management, habitat restoration, education, and enforcement, SWCR strives to restore ecological integrity while honouring both the natural and cultural heritage of the area. SWCR remains a model for long-term conservation in the Carolinian region.
Vegetation Management
The St. Williams Conservation Reserve (SWCR) is a living record of over a century of ecological restoration, dating back to the establishment of the St. Williams Forest Station in 1908—Ontario’s first provincial forest station. In response to severe land degradation caused by deforestation and agriculture, early conservationists began stabilizing the region’s windblown, sandy soils by planting coniferous trees. These plantations—composed primarily of native and non-native conifers—helped anchor the soil and marked the beginning of large-scale reforestation efforts in Ontario. Many of these conifer plantations still exist today and stand as historical evidence of early environmental restoration techniques.
As the plantations matured, the site became a testing ground for various forest management practices. Some of these stands will be retained to showcase this history, offering opportunities for research, education, and public demonstration. Representative examples of the original conifer plantations will be protected to honour the legacy of the foresters and conservationists who transformed barren lands into productive forests.
However, many plantations at SWCR were established in areas that were originally oak savanna or oak woodland—now recognized as some of the most endangered ecosystems in North America. These communities once dominated the local landscape and supported a rich diversity of species adapted to open, fire-influenced environments. The underplanting of conifers in these areas dramatically altered their structure and function, reducing biodiversity and shading out native species.
Restoring these historically significant communities is a key objective of the Conservation Reserve. Where plantations now occupy former savanna and woodland, gradual conversion to natural ecological communities is underway. This process involves using silvicultural techniques such as thinning, cutting, and occasionally girdling or brushing to open up the canopy, reduce competition, and allow sunlight to reach the ground—conditions essential for regenerating savanna species.
Some merchantable timber removed during restoration or thinning may be salvaged, with revenues reinvested in future ecosystem restoration activities. This approach supports a self-sustaining model for ecological recovery while balancing respect for the site’s forestry heritage with a forward-looking vision for biodiversity and ecosystem function.
In restoring SWCR’s natural communities, we not only protect rare species and habitats, but also continue a legacy of environmental stewardship that began over a century ago—adapting historic practices to meet today’s conservation challenges.
Invasive Plant Control
Invasive plants can be native or non-native plants and are characterized by their growth behaviour: they spread aggressively and outcompete other more desirable vegetation for sunlight, space, and nutrients. This hostile behaviour can pose a significant threat to the ecological integrity of the SWCR.
Non-native invasive plants are species that are introduced from other regions that lack natural predators or environmental checks. This allows them to spread rapidly and typically create mono-cultures – areas dominated by a single species. Examples of invasive non-native plants within the SWCR include Garlic mustard, Dame’s rocket, Spotted knapweed, Autumn olive, and Multiflora rose.
Aggressive native plants can also behave invasively, particularly when natural disturbances like fire or grazing are supressed or eliminated. These species can dominate an area and reduce the habitat’s diversity. Examples of aggressive native plant species within the SWCR include Red maple, Canada goldenrod, Staghorn sumac, and Wild raspberry.
Effective invasive plant control is essential for restoring, maintaining and encouraging the various unique habitats throughout the SWCR. Three methods of control include selective herbicide application, mechanical control, and manual removal.
Selective herbicide application is a targeted and efficient method to control persistent invasive species with extensive root systems or large seedbanks. Herbicides can be applied in precise doses directly to leaves, stems, or trunks of invasive plants, minimizing harm to surrounding vegetation. At SWCR, herbicide is typically used to control widespread occurrence such as Autumn Olive, Multiflora Rose, and Garlic Mustard, which can form dense thickets that shade out native grasses, wildflowers, and oak seedlings.
Brush saws are used to knock down dense woody stems that are preventing sunlight from reaching the canopy floor or are outcompeting more desirable plants. This is particularly important in habitats such as oak savannas and sand barrens, where open canopies and sunlit understories are essential. One specific example that applies to the SWCR involves Red maple saplings: When left uncontrolled, the dense stems of young red maples prevent air movement through the forest and crowd the provincially endangered Eastern Flowering Dogwoods. The excess shade and poor air movement create ideal conditions for dogwood anthracnose, the primary disease that kills Eastern Flowering Dogwoods.
Controlling invasive plants is an ongoing and seemingly unending activity, but it is also a foundational step in ecological restoration. Without continuous, effective management, invasive plant species would continue to expand, crowding out native plants, and therefore push out native insects, birds, and mammals.
Prescribed Burns
Oak savanna and sand barren habitats are fire-adapted ecosystems that depend on periodic burning to thrive. Historically, naturally occurring fires shaped these landscapes by reducing tree encroachment, recycling nutrients, and creating the open canopy that is needed by many native plants and wildlife species.
Much of the vegetation that thrive in these fire-adapted ecosystems, including oak leaves and prairie grasses, are highly flammable, enabling fire to spread effectively across the landscape. Fire rejuvenates fire-adapted species, knocks back the invasive plants that cannot tolerate heat, and helps break down the duff layer. Regular fire events prevent the buildup of dry leaves, branches, and dead vegetation, which reduces the risk of uncontrolled wildfires.
To maintain and restore these unique ecosystems, the SWCR carefully applies low-intensity prescribed burns (LIPBs) on a rotating schedule across designated burn blocks located throughout the SWCR. These burns are carried out in strict accordance with the Fire Management Policy for Provincial Parks and Conservation Reserves (PL 3.03.09) and the Class Environmental Assessment for Provincial Parks and Conservation Reserves.
Each prescribed burn is developed and overseen by a qualified burn boss and supported by partnerships with the Ministry of the Environment, Conservation and Parks (MECP), the Ministry of Natural Resources (MNR), and the Norfolk County Fire Department. The timing of each burn is carefully selected based on multiple factors, including weather conditions, wind speed and direction, and seasonal considerations. In southern Ontario, prescribed burns typically take place in early spring—before migratory birds begin nesting and before reptiles such as snakes become highly active.
Because the SWCR lies within a diverse and sensitive Carolinian zone, prescribed burns are conducted under strict protocols tailored to protect species at risk and ensure public safety. These guidelines include detailed site assessments, species monitoring, community notifications, and real-time decision-making to minimize any risk while maximizing ecological benefit.
Prescribed burns are a crucial part of the ecological restoration goals held be the SWCRCC. Without fire, oak savanna and sand barren habitats would gradually disappear, along with the many plants and animals that depend on them.
Restoration with native plants
The St. Williams Conservation Reserve Community Council (SWCRCC) is working towards restoring hundreds of acres of old pine plantations to pre-settlement habitats, like the oak savannas that once covered much of this area. Most of these pine plantations were planted in the early 1900’s in an effort to prevent the topsoil from blowing away after the land was cleared.
While the trees helped stabilize the soil, they also changed the natural environment and crowded out many native species. Now, as the SWCRCC decides to slowly remove the pine plantations and control invasive plants, it is evident that the native seedbank has been depleted, and therefore the plant communities that were historic to the area cannot establish without some outside support.
Purchasing native plants and seeds is not a financially sustainable option for the SWCRCC, and thus the idea for the Steppingstone Seed Orchard was formed
The Steppingstone Seed Orchard
In 2023, with support from Carolinian Canada’s Conservation Impact Bond, the idea for the Steppingstone Seed Orchard became a reality. Native plants and seeds were planted in small groups throughout a recently cleared section in Turkey Point. The idea is simple: by planting small patches—or “stepping stones”—of native grasses, wildflowers, and shrubs, we give nature a head start.
These stepping stones will act as living seed banks, preserving the genetic diversity of native plants that are disappearing from the area; provide seeds and cuttings we can use to restore other parts of the reserve; and will spread naturally over time, helping rebuild healthy, connected plant communities across the old plantation sites.
These plantings are a key part of restoring the oak savanna landscape—not just for plants, but for the birds, butterflies, and other wildlife that depend on them.
Get Involved Today!
The St. Williams Conservation Reserve Community Council is always looking for helpful volunteers and directors. Are you looking to give back to your community?
