Endangered Plants

A species is endangered if there are threats to its survival. The major factors that put plant species at risk stem primarily from human activity, including the conversion of natural habitats into land for agricultural, urban and industrial purposes. In Canada, these activities threaten entire natural ecosystems, such as older forests and Prairie grasslands. As of 2017, of the approximate 7,300 species of flora in Canada, 233 are at risk.

Small white lady's slipper (Cypripedium candidum), photo taken on 8 June 2013.

Designations and Legislation

The Government of Canada passed its first Endangered Species Act in 2002. That legislation empowered an organization called COSEWIC (the Committee on the Status of Endangered Wildlife in Canada) to designate species as being at risk. COSEWIC is funded by Environment Canada, but it operates independently of the government. The organization commissions studies of native species whose survival in Canada might be at risk. Based on that research, COSEWIC designates species as being in one of several categories of conservation risk: extinct, extirpated, endangered, threatened, or special concern.

Although Canada and its provinces and territories have legislation that protects species-at-risk from direct exploitation, such as harvesting for commercial purposes, the laws are generally weaker in terms of protecting natural habitats. Consequently, there are few cases of successful prosecution of people or companies that have caused damage to critical habitats.

At-Risk Flora

Canada has around 7,300 species of flora, including about 3,300 species of native vascular plants, 1,500 bryophytes (mosses and liverworts) and 2,500 lichens. Lists of rare plants have been compiled by botanists working with COSEWIC and other organizations, such as the National Museums of Canada and Agriculture and Agri-Food Canada, with the assistance of specialists from across the country. Similar lists have also been produced for the provinces and territories. As of 2017, COSEWIC has designated a total of 735 species as being at risk in Canada, including 196 species of vascular plants, 16 bryophytes and 21 lichens (the remaining species are animals; see also Endangered Animals).

Rare or potentially endangered plants can be divided into three groups: endemic species that occur only in Canada or in restricted areas straddling the national boundary with the US; plants of widespread occurrence that have become so rare throughout their range that they are in danger of extinction; and plants of widespread occurrence that are only endangered in the Canadian area of their range.

Regional Examples

British Columbia and Ontario have by far the largest numbers of rare plants, many of which are species that are more common in the US and reach their northern limit in Canada. Unfortunately, the Canadian population and most agricultural and industrial activity are concentrated along the Canada-US border, meaning most of these plants’ once-extensive natural habitats have been damaged or destroyed. For instance, only a few per cent remains of the deciduous forests that once covered southwestern Ontario, but these habitats support a diverse assemblage of plants that are found nowhere else in Canada.

Cucumber magnolia (Magnolia acuminata), photo taken on 3 May 2012.
Blue ash (Fraxinus quadrangulata), photo taken on 30 June 2014.
Eastern flowering dogwood (Cornus florida).
Kentucky coffee-tree (Gymnocladus dioicus).
Shumard oak (Quercus shumardii), photo taken on 17 October 2012.
Goldenseal (Hydrastatis canadensis).

Most of these Ontario-based plants are now rare, and some are on the verge of extirpation and even extinction. Trees included on the at-risk list include the cucumber magnolia (Magnolia acuminata), blue ash (Fraxinus quadrangulata), eastern flowering dogwood (Cornus florida), Kentucky coffee-tree (Gymnocladus dioicus) and Shumard oak (Quercus shumardii). Associated with them are many herbaceous plants, shrubs and climbers, including the small white lady's slipper orchid (Cypripedium candidum) and the medicinally important goldenseal (Hydrastis canadensis). Most of these southern plants survive in small woodlots and associated habitats, which are ecological fragments of the almost continuous forest that covered this region before European settlement. Fortunately, there have been increasing efforts by governmental authorities and non-governmental conservation organizations to secure the best of the surviving forests and to set them aside as protected areas to benefit the rare plants and animals that live there. This protection has been achieved by land acquisition and stewardship agreements with local landowners.

Furbish's lousewort (Pedicularis furbishiae).
Goldcrest (Lophiola aurea), photo take on 15 May 2016.
Redroot (Lachnanthes caroliniana), photo taken on 18 November 2008.
Thread-leaved sundew (Drosera filiformis), photo taken on 15 July 2009.

Similar problems exist in other provinces. In Nova Scotia and New Brunswick, many plants characteristic of the Atlantic seaboard and the eastern forests are threatened by cottage developments, agriculture, forestry and dam construction. These include Furbish's lousewort (Pedicularis furbishiae), goldcrest (Lophiola aurea), redroot (Lachnanthes caroliniana) and thread-leaved sundew (Drosera filiformis).

In the Prairies, almost all the natural grassland has been converted to agricultural use or is heavily grazed. Many prairie plants now survive precariously on limited areas of natural habitat or along roadsides and railway tracks, where they escape the pressures of agriculture but may still be threatened by the use of herbicide. Plant species at risk in the Prairies include small-flowered sand-verbena (Tripterocalyx micranthus), smooth goosefoot (Chenopodium subglabrum) and slender mouse-ear-cress (Halimolobos virgata).

Beargrass (Xerohyllum tenax), Glacier National Park, Montana, 20 July 2014.
Sandwort (Minuartia nuttallii), photo taken on 30 June 2012.
Townsendia daisy (Townsendia condensata), photo taken on 22 July 2013.

The western mountains have their own unique group of alpine flowers. Many species, although common in the US, reach their northern limit here and are rare. Examples include beargrass (Xerohyllum tenax), a sandwort (Minuartia nuttallii) and the beautiful Townsendia daisy (Townsendia condensata).

International Agreements

Plant species at risk are also designated in other countries using their own procedures and on a global basis by the International Union for the Conservation of Nature (IUCN). In addition, Canada is a signatory to the Convention on International Trade in Endangered Species (CITES), which regulates trade in rare and endangered species or their by-products. Canada has also ratified the International Convention on Biological Diversity and thereby assumes certain obligations for conserving biological diversity (see Biodiversity). Because these international treaties involve Canada as a whole, all levels of government are held to their provisions and responsibilities, as is society as a whole.

The protection that CITES provides is in the form of controlling the trade and movement of the listed species across international borders, but most of Canada's flora falls outside these regulations. This is because not many Canadian species are included on the CITES list of plants whose international trade is forbidden, although it does include all of Canada’s native orchids and cacti. One familiar plant that is covered is ginseng (Panax quinquefolius), a once abundant but now endangered plant of the deciduous forests of eastern and central Canada, whose roots were excessively harvested and sold for their reputed medicinal properties.

Habitat Protection

While it is obvious that protection from overharvesting is needed to save a species from extinction, it is also true that the natural habitats that provide their home must also be conserved. The conservation of habitats is achieved by various organizations in Canada. The principal role is played by federal, provincial, territorial, municipal and Indigenous governments. Any of those governments can proclaim areas of land that they own as being a protected area in which intensive economic uses are not permitted. The most highly protected areas are ecological reserves and wilderness areas, in which only a low intensity of use is permitted, such as hiking and nature study. Parks are also a kind of protected area, although often a great deal of economic activity is permitted, sometimes including large roadways and major tourism-related developments.

The private sector also has a key role to play in protecting natural habitats. For example, many large forestry companies have set aside parts of their land base to conserve natural habitats. In addition, many individual landowners manage their land to conserve habitats needed by native species. Finally, certain non-governmental organizations, such as the Nature Conservancy of Canada and Ducks Unlimited Canada, are acquiring private properties that have good natural values and setting them aside as protected. To do that, those environmental charities raise money from all sectors of Canadian society — from individuals, companies, foundations and governments — and they use those funds to do conservation planning to identify the most important properties to acquire.

Reasons for Preservation

Plants vary depending on where they grow, for example, northern populations often differ genetically from southern ones. Each has become adapted to the specific habitat and climate in which it grows. For the continued survival of a species, it is essential that the diversity of its gene pool be maintained so that it can adapt to continual changes in the environment, shifts in climate, and varying pressures from predators, disease and competition. For this reason, it is important to protect those plants that reach the northern limits of their range in Canada, even though they may be abundant in the US. Also, it is essential to protect the wild ancestors of cultivated plants and ensure the survival of others that may be potentially useful as new crops, horticultural varieties or sources of useful products.

Medicines are among the list of useful products generated by plants, and have been since prehistoric times. Research is discovering an apparently unlimited source of new chemicals in wild plants, many of which can form the basis for new drugs or other products important to human well-being. For example, cortisones were originally developed from wild yams (Dioscorea) and the jojoba bean (Simmondsia chinensis), an obscure shrub in the semi-desert of Arizona, was found to be a source of a liquid wax that can be used in the manufacture of products ranging from transmission oil to cosmetics and suntan lotions.

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Further Reading

  • B. Freedman, Environmental Science. A Canadian Perspective, 5th ed. (2010).

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