A principle role for Canada's national parks is to provide habitat for the plants and animals that are typical of the natural area in which the park is located. Parks provide habitat for very common species as well as rare and Species at risk. Each park has a list of the major plant and animal species that occur in the park, and these species are tracked using the Species-In-Parks (SIPS) database. The species list is updated, as new information is made available.

It is obviously impossible to count the thousands of species that occur in our national parks. However, for many of the main species, such as mule deer, white-tailed deer, moose, Rocky Mountain elk, mountain goat, mountain sheep, caribou, and grizzly bears, Parks Canada biologists conduct regular surveys to estimate how many animals occur in and around a particular park. This work is often carried out with partners such as the Canadian Wildlife Service or provincial and territorial governments.

The hundreds of species that make up a park species list are actually only a small percentage of the total number of species that occur in a park. There are thousands of species of insects, invertebrates, protozoans, fungi and bacteria that occur in the millions in all of our park ecosystems. For example, it has been estimated that there may be thousands of species of these organisms in a single handful of forest soil.

Michigan lily (Lilium michiganese), Point Pelee National Park of Canada
Children surrounding a large cedar on the Giant Cedar trail in Mount Revelstoke National Park of Canada
Long-horned Beetle, La Mauricie National Park of Canada
Grizzly bear (Ursus arctos), Kluane National Park and Reserve of Canada

These thousands of species perform very important ecological functions such as pollination of plants by insects, decomposition of leaf litter on the forest floor by bacteria that provides essential nutrients for tree growth, and fungi that live inside tree roots and help trees take up water and nutrients out of the soil.

We will probably never know all of these species and we certainly won't be able to count them all. The way we manage our parks to try and make sure that these species persist is by making sure that the range of ecosystem types that are typical of a natural region are represented across the park landscape. This is one of the principle functions of developing an inventory of park ecosystems.

Inventories of park ecosystem types are conducted periodically to provide an assessment of the distribution and condition of park ecosystems. This inventory needs to be updated periodically to account for changes in ecosystems that result from ecosystem succession and disturbance. Ecosystems change over time in a process called ecosystem succession.

For example, forest trees grow and die and are replaced by younger trees that were growing slowly under the canopy. Forest ecosystems may also change very rapidly in response to large-scale disturbances such as forest fires, insect infestations, or landslides, and this initiates a new progression of forest ecosystem succession. Other ecosystems such as wetlands and grasslands also change slowly over time, and may be altered dramatically by disturbance.