Threats to Survival
Extinction, a natural process that has occurred throughout world history, takes place when an organism is unable to adapt to a changing environment or to compete with better adapted species. In recent times humans have become the major threat to the survival of many plants. Technological developments in industrial nations and increasing pressure for agricultural land in developing countries, combined with the exploitation of timber, minerals and other natural RESOURCES, are causing rapid environmental changes. These threaten whole ECOSYSTEMS, such as the rain forest in tropical countries and the coastal forests of British Columbia. As a result, the survival of thousands of plant species is threatened.
Because destruction of habitat is now the principal cause of endangerment, habitat protection is the only effective way to save plants from extinction. Growing a plant in a BOTANICAL GARDEN is no substitute for maintaining it in its wild habitat. Botanical gardens can, however, be useful in providing a reservoir of material to restock wild populations of endangered plants.
Legislation protecting rare plants in Canada is fragmentary and of limited effect. As a natural resource, plants are a provincial rather than a federal responsibility; hence, each province must enact its own endangered species legislation. However, the federal government, as a signatory of the Convention on International Trade in Endangered Species of 1973 (CITES), is able to provide protection for plants that are on an internationally accepted list of controlled species.
Few Canadian species are included on this list, though it does include all ORCHIDS and CACTI.The protection that CITES provides is only in the form of controlling the trade and movement of the listed species across international borders, and most of Canada's flora falls outside these regulations. One familiar plant that is covered is GINSENG (Panax quinquefolius), of the deciduous forests of eastern and central Canada. Its roots are harvested and sold for their reputed medicinal properties.
Canada also ratified the International Convention on Biological Diversity in 1992, and having done so made a commitment to, among other things, enact legislation to protect endangered species.
Most provinces have endangered species legislation. Typical is the Ontario Endangered Species Act, which states that "no person shall wilfully destroy or interfere with the habitat of any species of fauna or flora declared in the regulations to be threatened with extinction." Unfortunately, very few plants have, as yet, been included in these regulations, hence this legislation has at present only limited effect in protecting rare plants. However, with increased pressure from botanists and the general public, protection can be extended to other species.
More effective protection comes from agencies whose objectives are to protect the natural environment and its associated BIODIVERSITY of plants and animals. National parks provide the most stringent, effective and lasting protection for Canadian flora. Many are situated in areas where rare plants occur, and part of the mandate of Parks Canada is to ensure the protection for all time of rare plants and their habitats.
The effectiveness of provincial parks and conservation authorities in protecting endangered species varies considerably. Many place greater emphasis on exploiting the natural environment for human enjoyment than on protecting habitats or rare plants; furthermore, any protection provided can be overridden without reference to Parliament. However, greater public awareness about the importance of rare plants is stimulating the conservation role of these agencies. Most provinces now have legislation enabling them to designate sensitive areas as wilderness and ecological reserves in which effective protection can be provided to any rare plants growing in them.
Under the aegis of UNESCO, through the Man and Biosphere programme (MAB), several biosphere reserves have been created in Canada. The objective of the programme is "to develop ... a basis for the national use and conservation of resources of the biosphere ... and to increase man's ability to manage efficiently" these resources. The importance of integrating ecological research and environmental training are emphasized. Biosphere reserves in Canada include Mont-St-Hilaire, Qué, and WATERTON LAKES NATIONAL PARK, Alta (together with the adjoining Glacier National Park in the US.)
Non-government agencies such as the Nature Conservancy of Canada and many local natural history societies are also playing a major role in habitat protection through land purchase and stewardship agreements involving privately owned land.
Canada's flora includes about 3300 species of native vascular plants. Lists of rare plants have been compiled by the National Museums of Canada with the assistance of botanists from across the country. Similar lists for each province and territory have also been produced. Over 1000 species are listed as rare in Canada, and of these, 214 are regarded as nationally endangered (or imperilled). Amongst the provinces, British Columbia and Ontario have by far the largest numbers of rare plants (426 and 355 respectively). However, many of these are species that are more common in the US and reach their northern limit in Canada.
Rare or potentially endangered plants can be divided into 3 groups: endemic species that occur only in Canada or in restricted areas straddling national boundaries; 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 part of their range.
Canadian endemic plants tend to be concentrated in several centres. Important centres from west to east are the region straddling the Alaska-Yukon border - endemics include an anemone (Anemone multiceps), 2 fleabanes (Erigeron mexiae and E. muiri) and a rare chickweed (Stellaria alaskana); HAIDA GWAII - a ragwort (Senecio newcombei), an avens (Geum schofieldii) and a small anemone (Enomium savilei); sand dunes on the south shore of LAKE ATHABASCA - a chickweed (Stellaria longipes ssp. arenicola), several dwarf willows and sea thrift (Armeria maritima ssp. interior); the shores of the Great Lakes - 2 thistles (Cirsium pitcheri and C. pumilum), an iris (Iris lacustris), Houghton's goldenrod (Solidago houghtonii) and a yellow daisy (Hymenoxys acaulis var. glabra); the Gulf of St Lawrence (eg, the mountains of the GASPÉ PENINSULA, ÎLES DE MINGAN and ÎLE D'ANTICOSTI and the limestone and serpentine tablelands of Newfoundland and Labrador) - a sandwort (Minuartia marcescens), a gentian (Gentianella victorinii), 2 roses and several willows.
In Canada, several species occur that are now so rare and restricted that their continued survival is endangered. Their rarity is usually caused by destruction of natural habitats. For example, the small white lady's slipper orchid (Cypripedium candidum), which was the first plant to be protected under Ontario law, now occurs only in a few small colonies in southwestern Ontario, Saskatchewan and Manitoba along with several isolated stations in the US.
The main threats to Canada's flora are to those plants that reach the northern limit of their range in southern Canada. Unfortunately, human population, agriculture and industry are concentrated in this region. Little now remains of the deciduous forests that once covered southwestern Ontario, but these forests support a large and very special assemblage of plants found nowhere else in Canada.
Most of these plants are now rare; some are on the verge of extinction; a few are extinct. Many trees are included in the list: magnolia (Magnolia acuminata), 2 hickorys (Carya glabraand C. laciniosa), blue ash (Franxinus quadrangulata) and 4 oaks. Associated with them are many herbaceous plants, shrubs and climbers, including the beautiful trumpet flower (Campsis radicans), the redbud (Cercis canadensis, extinct as a wild plant in Canada) and the medicinally important goldenseal (Hydrastis canadensis).
Most survive in small woodlots and associated habitats, fragments of the almost continuous forest that covered this region before European settlement. Fortunately, over the past decade the Carolinian Canada Program - a co-operative endeavour involving the Ontario Government, local conservation authorities and the private sector- has succeeded in protecting many of the most important remnants of this vegetation together with the rare plants and animals that live there. This protection has been achieved by land acquisition and stewardship agreements with local landowners.
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 goldcrest (Lophiola aurea), redroot (Lachnanthes tinctoria) and Furbish's lousewort (Pedicularis furbishiae).
On the prairies, almost all the natural grassland has succumbed to the plough or is heavily grazed. Many prairie plants now survive precariously along roadsides and railway tracks, where they escape the pressures of agriculture but are threatened by herbicides. Examples include legumes such as Astragalus kentrophyta and Oxytropis besseyi, prairie parsley (Lomatium orientale) and ironweed (Vernonia fasciculata).
The western mountains have their own unique assemblage of alpine flowers. Many species, although common in the US, reach their northern limit here and are rare. Examples include beargrass (Xerohyllum tenax), a lowly sandwort (Minuartia nuttallii) and the very beautiful Townsendia daisy (Townsendia condensata).
Reasons for Preservation
Why protect plants from extinction? Why not let nature take its course and allow plants to die out? There are many reasons. Plants afford pleasure and relaxation to many people, and provide a source of inspiration in most art forms: painting, photography, poetry and prose. All life, as well as the quality of life, depends on plants, yet only about 30 kinds have been exploited to form the world's major food crops (eg, rice, wheat, corn, potatoes). The potential for producing new crops and for improving existing ones is unlimited, but this depends on using the genetic diversity found in wild plants.
Plants vary depending on where they grow; eg, northern populations often differ genetically from southern ones. Each has become adapted to the 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 the continual small changes in the environment, shifts in climate, changing pressures from predators, disease, competition, etc. For this reason, we must protect those plants that reach the limits of their range in Canada, even though they may be abundant in the US. Also, we must protect the wild ancestors of cultivated plants and to ensure the survival of others that may be potential new crops, new horticultural varieties or new sources of useful products.
Plants have been a major source of medicines since prehistoric times. Modern 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 and development. Cortisones were originally developed from wild yams (Dioscorea), and an obscure bush in the semidesert of Arizona, the jojoba bean (Simmondsia chinensis), has been found to be a source of liquid wax, which can be used in the manufacture of many products ranging from transmission oil to cosmetics and suntan lotions.
The paw paw tree (Asimina triloba), which grows in the forests of eastern North America from southern Ontario to the Gulf of Mexico, has recently been found to contain a powerful anticancer drug. Similarly, a little-known vine (Ancistrocladus konepensis) grown in the West African rainforest contains a substance that inhibits HIV (see AIDS).
The potential for economic and material benefit is unlimited, for we have barely begun to exploit the wealth of useful products contained in wild plants. At this early stage, we cannot afford to let plants become extinct - once lost, a species can never be recreated. Plants are a part of our natural heritage - a heritage that we have an obligation to preserve for the benefit of future generations of mankind.
Author JOHN MORTON
Links to Other Sites
Endangered Species in Endangered Spaces
An informative website about rare and endangered plants and animals in the Thompson-Okanagan region of British Columbia. Click on the menu at the left side of the page for information about specific species. From the Royal British Columbia Musuem.
The website for "Davidsonia," a journal that provides original, review, discussion or summary work that is of interest to the botanical and botanical garden communities at large. Offers full text articles online. From the University of British Columbia.
The Plant List
Search this online database for information about one million plant species from around the world. Also, click on "major plant groups" at the bottom of the page to browse descriptions of species of interest. Fungi and algae are excluded. From the Royal Botanic Gardens, Kew, in the UK and the Missouri Botanical Garden in the US.
Canadian Biodiversity Website
A great information source for all budding biologists. Learn about biodiversity theory, natural history, and conservation issues. From McGill’s Redpath Museum.
Species at Risk Public Registry
A searchable database of Canadian species at risk. Provides illustrated natural histories of each species as well as information about recovery programs, a glossary, and more. From Environment Canada.
This website offers access to the “Red List,” a detailed, searchable database of flora and fauna facing extinction. Categories range from critically endangered to vulnerable. Note: select “Canada” for an extensive list of Canadian species at risk of extinction. From the International Union for the Conservation of Nature and Natural Resources, the world’s largest conservation network.
Ontario: Species at Risk
A list of official status designations assigned to native Ontario species by the Ontario Ministry of Natural Resources. Categories include: Extinct, Extirpated, Endangered, Threatened, Special Concern, Not at Risk, and Data Deficient.
Quebec Society for the Protection of Plants
The Society brings together researchers from universities and federal and provincial governments, agronomists, biologists, professional foresters, technologists, students, as well as any person interested in plant protection. Members of the Society are concerned with theoretical and practical aspects of plant protection.
Endangered Species and Ecosystems
This site is a gateway to information about endangered species and ecological communities (ecosystems) in British Columbia.
A brief profile of Carl Linnaeus and the binomial naming system he devised for living organisms. From the website for the Linnean Society of London in the UK.
Convention on Biological Diversity
An extensive resource about international policies and initiatives related to environmental conservation and biodiversity. Click on "International Year of Biodiversity" for news about special events on biodiversity.
Tree of Life
Explore the diversity of Earth's life forms at the Tree of Life website. Also includes beautiful photographs, an extensive glossary of biological terms, and "Treehouses" for younger readers.