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Todmorden Mills Wildflower Preserve

Natural History

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The species composition and abundance of plant and animal species that live in the Todmorden Mills Wildflower Preserve today reflects both historical and existing factors. Firstly, many original native species were lost when the forest was cleared and site was transformed in the 1800s into a small village. The addition of fill and garbage to the site, and the re-routing of the Don River, also had a major impact. The Preserve has been re-colonized, but primarily by non-native plants. Finally, a number of native species have been recently re-introduced as part of the TMWPC restoration efforts.

In 2003, TMWPC commissioned am environmental study of the Preserve. Much of the information that follows is derived from the report, which can be ordered from the TMWPC at a cost of $15 (shipping and handling included).

Vegetation Communities

The Preserve can be described in terms of the types of vegetation communities. The communities in the Preserve have been identified and mapped using the Ecological Land Classification system developed in Ontario (Lee et al 2000). A detailed and complete description of the communities and a map of their distribution in the Preserve is available in Kamstra (2003). Here we summarize the major habitats in the Preserve:

Deciduous Forest and Woodland
About two-thirds of the Preserve is forest (defined as having a canopy cover of 60% or more) or woodland (defined as an area of trees where the canopy is incomplete and from 25% to 60%) in which the dominant species are Manitoba Maple, Crack Willow, Norway Maple and Black Locust.
A thicket is comprised of shrubs, and a few trees with an understorey of predominately grasses. This is a successional habitat which will gradually become a woodland. Characteristic plant species in the thickets include Alternate-leaved Dogwood, Wild Grape, and Dog-strangling Vine.
A meadow is predominated by grasses and wildflowers and has fewer shrubs and trees than a thicket. It is an early successional habitat that will eventually become thicket and then woodland. characteristic plants of the meadows at Todmorden include Kentucky bluegrass, Canada goldenrod and asters. Characteristic animals of this habitat include Cottontail Rabbit, Goldfinch, and Monarch Butterfly.
A swamp is a forested wetland, and in the Preserve this habitat occurs where there is seepage of water from the slopes. Swamps have characteristic ground plants that can tolerate wetsoils, such as Spotted Jewelweed and Skunk Cabbage.
A marsh is an open wetland with grass-like plants. This habitat is a successional one and eventually transforms into swamp as trees and shrubs invade and form a canopy. Some characteristic marsh plants include cattails, common reed and sedges. Characteristic animals include Red-winged Blackbird and Muskrat.
Open Water
The pond and the oxbow provide open water which is permanent even in a dry summer. Characteristic plants of this habitat include pondweed, waterlilies and filamentous algae. Animals that like this habitat include Mallard Duck, Belted Kingfisher, and dragonflies.


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Skunk Cabbage (Symplocarpus foetidus) flower in early spring.
A total of 375 species of vascular plants have been recorded at Todmorden Mills. A complete list is available in Kamstra (2003). About one-third of the species are non-native, many of which have colonized the site naturally. Of the approximately 240 native species present, at least 150 species have been planted in the last ten years as part of the restoration effort. It is likely that the total number of plant species will continue to increase gradually as overlooked species are discovered, new non-native species colonize, and as additional native species are planted.

Rare Plants

Some of the native plants in the Preserve are considered special because they are regionally rare. Surveys by botanists have yielded 11 rare species in the Preserve. These include a sedge, two trees (Red Cedar and Slippery Elm) and herbaceous plants, most of which live in wetland habitats. One, the Skunk Cabbage, is quite common at Todmorden Mills.

Non-native plants

Non-native plants, those species that did not grow here naturally prior to European settlement, now predominate at Todmorden Mills. While they represent just one-third of the species representation, they comprise over three-quarters of the plant biomass in the Preserve.

Most of the non-native species have been introduced from Europe and Eurasia in the last 200 years. Many of these species are more abundant here than in their natuve range, and this is thought to be because their natural predators and competitors are not present here.

At least half the non-natives in the Preserve are so successful that they are considered invasive and a threat to native plants and the vegetation communities which the TMWPC ais trying to restore. Among the invasives, some species have been identified as particularly threatening (Havinga 2000). At Todmorden, these include Manitoba Maple, Garlic Mustard, Pale Swallow-wort (also known as dog-strangling vine), Himalayan Balsam, Black Alder, Common Reed and Japanese Knotweed.

Native Trees and Shrubs

There are 114 trees and shrub species in the Preserve, of which 78 (68%) are native. The most abundant native trees are (in no particular order of abundance): American elm, Eastern cottonwood, Trembling Aspen, Sugar Maple, White Ash, Silver Maple, and Eastern White Cedar.

Shrubs are small trees which tend to be understorey elements in forest and which often have multi-branched form. Alternate-leaved Dogwood (also called Pagoda Dogwood) and Choke Cherry are the most abundant and widespread native shrubs in the Preserve. Apple trees and hawthorns are also widespread.

Native Wildflowers

Wildflowers, roughly defined as herbaceous plants with showy flowers which grow in natural areas (outside cultivation), are the original inspiration for creation of the Preserve. If we exclude the sixty species of ferns, grasses, sedges and allies, we are left with 200 wildflowers in the Preserve.

In the meadow habitat, wildflowers in the Aster (Compositae) family, one of the most speciose families, predominate. Among the 50 species of composites are favourites such as New England aster, Black-eyed susan and Canada goldenrod. One-third of the Aster family is non-native, and includes some abundant and well-known species such as Wild Carrot and Chicory.

Forest and woodland wildflowers include the spring ephemerals which founder Charles Sauriol was keen to re-establish. Some, such as Jack-in-the-pulpit and Skunk Cabbage, have survived from the original forests, Others such as White Trillium, Bloodroot and Wild Columbines have been reintroduced and have established.

Marsh and swamp wildflowers of note include Marsh Marigold, Turtlehead and Spotted Jewelweed.

A checklist of the common wildflowers is available here.


Grey Squirrel
Some general intro text here.


Nine species of mammals have been recorded at Todmorden Mills. Grey Squirrel and Raccoon are seen regularly. A Muskrat was present in the pond in the summer of 1996 when it ate many recently-planted wetland plants. Muskrat was again seen in the Preserve in the summer of 2003. Six additional species including Striped Skunk and Woodchuck have been reported (Herzberg and Juhola, 1987).

A checklist of mammals seen at Todmorden Mills is available here.


A total of 94 bird species have been recorded in the Preserve. Most are transient, passing through on migration in spring or fall, but about 30 bird species reside at Todmorden. Residents include the Red-winged Blackbird which arrives in April and nests in the marsh at the pond and at the back of the Preserve. Baltimore Orioles build their distinctive basket-like nests in tall trees in the Preserve.

A checklist of birds at Todmorden is available here.

Amphibians and Reptiles

Garter Snakes and Brown Snakes occur at Todmorden Mills. Green Frog is common in the Pond, and American Toads have been reported historically.

A list of reptiles and amphibians reported in the Preserve is available here.


At least two fish species have been observed at Todmorden Mills; Brook stickleback (Culaea inconstans) and Creek Chub (Semotilus atromaculatus).


The most conspicuous insects at Todmorden are the butterflies and dragonflies. A preliminary list is available here.

A non-native ant, Myrmica rubra, is extremely abundant at Todmorden Mills. It has a nasty bite. The ants are most active in summer and early fall.