Vegetation Communities of Tommy Thompson Park

Due to the differing ages of different sections of the park and the various habitats associated with those sections, as well as the levels of disturbance, moisture and nutrients, there is a high diversity of vegetation found at TTP. Vegetation can be characterized by community, as plant species with similar ecological requirements and adaptations are generally found in comparable environments. Many species, however, can be found in more than one community; therefore it is the assemblage of species that form the community.

Human or cultural influence is very apparent in most vegetation communities due to the nature of TTP, as well as urban pressures. Cultural influence is often in the form of non-native and/or invasive vegetation, however all restoration efforts include only native species. The dominant vegetation community in the park is meadow, followed by poplar forests, meadow marshes, sand dunes and beach/bar communities. There are, however, smaller vegetation communities as well including thickets, savannahs, swamps and other wetlands.

Vegetation communities will continue to change as the park evolves and natural succession progresses. For example, in the short-term some meadows will start producing woody vegetation and the transition to forest will be underway. Long-term, generations from now, TTP may look very different with plant communities that have developed only because natural processes have created suitable conditions.

Meadows

Meadows are open areas, characterized by a mix of grasses and wildflowers with few trees and/or shrubs. Meadow communities at TTP are defined as dry, moist and wet based on the plant species present and all communities have evidence of human influence. The most obvious meadows at the park are along the neck.

Common Species:
Canada thistle (Cirsium arvense)*
Common tansy (Tanacetum vulgare)*
Chicory (Cichorium intybus)*
Viper's bugloss (Echium vulgare)*
Canada goldenrod (Solidago canadensis)
Boneset (Eupatorium perfoliatum)
Scouring rush (Equisetum hyemale)

Forests, Woodlands and Thickets

These communities are dominated by trees or shrubs. Generally, forests have more than 60% tree cover; woodlands have at least 35% but less than 60% tree cover; and thickets have less than 25% tree cover, but more than 25% shrub cover.

The dominant forest community at TTP is poplar deciduous. It is the most mature community at TTP, yet it is still at a young stage since the Spit is less than fifty years old. The original cottonwoods to colonize the TTP probably grew from light-tufted seeds carried by the wind from the Toronto Islands. The best representation for this community is Peninsulas B and C.

Common Species:
Eastern cottonwood (Populus deltoides)
Trembling aspen (Populus tremuloides)
Balsam poplar (Populus balsamifera)
Sandbar willow (Salix exigua)
Red-osier dogwood (Cornus stolonifera)

Beaches, Sand Barrens and Sand Dunes

These communities all have sand in common, however at TTP barrens consist of slabs of concrete covered by little or no soil. Beaches tend to have few plants near the shoreline due to wave and ice action. Trees are uncommon and shrubs are short or creep along the ground. Sand barrens also have few plants due to the lack of soil. Plants that are present grow by rooting in cracks in the rock or in very shallow soil. Sand dunes are generally dynamic and vegetation can range from thickets to patchy grasses to barren with species variability depending on available moisture. Look for these communities along the north shore of the park.

Common Species:
Canada bluegrass (Poa compressa)*
Sandbar willow (Salix exigua)
Eastern cottonwood (Populus deltoides)
Common mallow (Malva neglecta)*
Lamb's quarters (Chenopodium album)*
Purslane (Portulaca oleracea)
Pearly everlasting (Ananphalis margaritacea)

 

Wetlands

TTP has several types of wetlands, as well as projects to create wetlands that will help compensate for the widespread loss of wetlands that were historically present in Toronto. Meadow marshes are seasonally inundated with water and are usually situated at the wetland-terrestrial boundary therefore may have a mixture of both terrestrial and wetland plants. Marshes have a significant amount of emergent vegetation and may have floating plants, as well as submergent aquatic plants, but few trees or shrubs. Swamp communities are dominated by standing trees and/or shrubs and include hydrophytic vegetation. The Cell One wetland and Triangle Pond are examples of marshes, while swamp communities can be found in the Baseland and along the back bays of Embayments B and C.

Common Species:
Blue vervain (Verbena hastata)
Purple loosestrife (Lythrum salicaria)*
Common cattail (Typha latifolia)
Common reed (Phragmites australis)*
Bulrush species (Scirpus sp.)
Willow species (Salix sp.)
Red-osier dogwood (Cornus stolonifera)
White birch (Betula papyrifera)
Poplar species (Populus sp.)

 

Aquatic

Aquatic habitats have submerged and/or floating vegetation communities. The composition of the community is based on a number of factors including soils, water depth and nutrient availability. When conditions are right you may be able to view submerged vegetation communities - look in Triangle Pond or the Cell One wetland.

Common Species:
Northern water milfoil (Myriophyllum sibiricum)
Eurasian water milfoil (Myriophyllum spicatum)*
Coontail (Ceratophyllum demersum)
Richardson's pondweed (Potamogeton richardsonii)
White water-lily (Nymphaea lotus)

 

* indicates non-native species