Tallgrass Prairie
An open, grass-dominated ecosystem characterized by tall grasses (1-2+ m), diverse forbs, and scattered shrubs. Once widespread in southern Ontario's warmer regions, now critically reduced to less than 3% of its original extent.
Physical Characteristics
Soils: Deep, fertile loam to sandy loam. Typically neutral to slightly alkaline pH. Well-drained. Historically maintained by periodic fire and grazing.
Characteristic Vegetation
- Andropogon gerardiispecies
- Sisyrinchium montanumspecies
- Schizachyrium scopariumspecies
- Sporobolus heterolepisspecies
- Sorghastrum nutans
- Asclepias tuberosaspecies
- Asclepias purpurascensspecies
- Asclepias syriacaspecies
- Symphyotrichum novae-angliaespecies
- Ceanothus americanusspecies
- Lupinus perennisspecies
- Pycnanthemum incanumspecies
- Gentiana andrewsiispecies
- Liatris spicataspecies
- Solidago nemoralisspecies
- Allium cernuumspecies
- Geum triflorumspecies
- Antennaria neglectaspecies
Characteristic Fauna
Details
Description
Tallgrass Prairie is one of the rarest ecosystems in Ontario, with less than 3% of its historic range remaining. Historically, this ecosystem covered significant portions of southwestern Ontario, particularly in the Carolinian Zone around Essex, Kent, Lambton, and parts of the Greater Toronto Area.
The community is dominated by warm-season grasses (C4 photosynthetic pathway) that typically grow 1-2.5 m tall. These grasses are interspersed with a highly diverse assemblage of broad-leaved herbaceous plants (forbs) that provide staggered blooming from spring through autumn.
Physical Characteristics
- Soils: Deep, fertile loam to sandy loam. Well-drained. Typically neutral to slightly alkaline.
- Moisture: Mesic to dry-mesic. Relies on deep perennial root systems (some exceeding 3 m) to access soil moisture during summer drought.
- Fire regime: Pre-settlement fire return interval of 1-5 years, primarily from lightning strikes and deliberate burning by Indigenous peoples. Fire prevents woody encroachment and recycles nutrients.
Characteristic Vegetation
Prairie structure includes multiple vertical layers:
- Dominant grasses: Big Bluestem (Andropogon gerardii), Little Bluestem (Schizachyrium scoparium), Indian Grass (Sorghastrum nutans), Switchgrass (Panicum virgatum)
- Spring forbs: Shooting Star (Dodecatheon meadia), Golden Alexanders (Zizia aurea)
- Summer forbs: Butterfly Weed (Asclepias tuberosa), Culver's Root (Veronicastrum virginicum)
- Late-season forbs: Smooth Aster (Symphyotrichum laeve), Stiff Goldenrod (Solidago rigida)
Characteristic Fauna
Tallgrass prairie supports many rare and declining species:
- Birds: Bobolink, Eastern Meadowlark, Grasshopper Sparrow, Northern Harrier
- Insects: Monarch Butterfly, numerous specialist bees (over 50 species of native bees documented in Ontario prairies), and prairie-dependent Lepidoptera
Ontario Distribution
Remnant prairies persist in:
- Ojibway Prairie Complex (Windsor)
- Walpole Island First Nation (Lambton County)
- Alderville Black Oak Savanna (Northumberland County)
- High Park (Toronto)
- Tiny pockets in Brant, Haldimand, and Norfolk counties