Conserving and restoring ecosystems
In Banff National Park, Parks Canada has adopted an ecosystem based management approach that fulfills its mandate to preserve ecological integrity in the park ecosystems and provide for visitor enjoyment and benefit. Ecosystem based management is a holistic approach in which decisions are made based on an understanding of the whole ecosystem rather than individual species or communities. Management decisions are based on current ecological information gained from science and traditional knowledge.
Central to the concept of ecosystem based management is that humans form an integral part of these systems. The ecosystems of Banff National Park were modified and influenced by native peoples 10,000 years before the arrival of Europeans. Current human use within and outside park boundaries continues to have an effect on park ecosystems. Ecosystem based management involves working with other agencies and groups and taking into consideration the economic and social needs of the people living in and around the park.
Philosophically, ecosystem-based management lies between the utilitarian view of land use for economic benefit and the romantic view that parks should be left as pristine wilderness, with no human presence.
Human-Land management philosophies
|Philisophical Assumptions||Nature serves humanity||Humanity part of nature||Humanity absent, or less important than nature|
|Human Expectations||Traditional resource harvest/use||Land ethic, Ecological integrity, Sustainability, health||Wilderness, natural, noble savage, pristine nature|
|Management Paradigm||Sustained yield||Ecological restoration||Natural regulation|
|Ecosystem Indicators||Units/ha Dollars/year Tourists/park Ungulates/ha||Biodiversity
|No human presence
Naturally evolving so no goals or indicators can be set
What is an ecosystem model?
A model is a representation of reality. Models take many forms including diagrams, pictures, small replicas of objects and computer simulations. Managers and scientists in national parks have created models that represent the structure, function and interaction of many living and non-living components of park ecosystems.
They use the models to predict how man-made or natural changes in one part of the system will affect the rest of the ecosystem.
Although models cannot perfectly duplicate the complex biological reality of an ecosystem, they serve as tools to aid park managers in making management decisions about vegetation and wildlife in parks. These models are also used to identify critical gaps in knowledge about ecosystem structure and function and to determine research needs.
Using a model to explain vegetation patterns
In Banff National Park, researchers have developed a conceptual model that illustrates the key factors influencing the patterns of vegetation that we see on the landscape. This model applies to the montane and subalpine ecoregions of the park. This is an important model for park managers because the structure and composition of vegetation determines the amount of available habitat and food sources for the park's wildlife species. The model also indicates how humans impact the major components of the ecosystem.
Climate and fire: major influences
Climate is the over-riding factor that determines the large-scale vegetation patterns in the park and the larger Rocky Mountain Ecosystem. Fire also has a major affect on vegetation in this region by breaking up the forest into a mosaic of different age stands and vegetation types.
© Ian Syme
Within each valley in the park the community of trees, shrubs and wildflowers varies with changes in topography, elevation and aspect. Small changes in local terrain can create microclimates that provide different growing conditions than the prevailing climate. Soil also influences which plants grow in an area and how much vegetation the area can support. Small-scale disturbance agents such as wind, avalanches, insects and disease damage or destroy small patches of forest resulting in gaps in the forest that contribute to the vegetation mosaic created by fire. Humans influence vegetation patterns by suppression of unwanted fire and the use of planned prescribed fires
Using a model to make management decisions
Researchers in Banff National Park have chosen five of the elements from the larger ecosystem model to study long-term changes in the montane ecosystem. By looking closely at the relationships between aspen, elk, wolves, fire and humans both historically and today it has been shown that the montane ecosystems in Banff National Park have changed significantly over the last 100 years. In fact, researchers now believe that the current conditions in the valley bottoms of the park have not existed at any other time in the last 10,000 years.
Park managers are using a condensed model to help make management decisions regarding both vegetation and the large mammals in the park in order to restore or maintain ecological integrity. The five elements were chosen for this model because they are well understood from previous research, they are good indicators of ecological integrity, they have changed significantly over the last two centuries, and they have a measurable effect on the montane ecosystem.
Changes in the Banff National Park ecosystem
- Native Americans set frequent, low intensity fires in the valley bottoms
- Aboriginal burning increased the production of plants used for food and created open grazing areas favoured by game species
- Native hunting helped to keep ungulate numbers low in pre-historic times
- Native burning eliminated from park
- Fire suppression and prescribed burning occurring
- High human use areas are systematically avoided by wolves and preferred by elk
- Elk habituation to high human use areas around townsites has resulted in high elk populations and vegetation over-browsing
- Repeat photographs reveal that the montane valleys in Banff National Park were much more open in the past
- Frequent low-intensity fires were the norm prior to park establishment with fires occurring less than 40 years apart on average
- Fire frequency has decreased dramatically leading to an accumulation of fuels on the forest floor
- With fire suppression, the forests in the park have become taller and more dense
- Grasslands, shrublands, open forest types and aspen communities have all declined markedly
- Explorers in the Canadian Rockies from 1792-1873 recorded very few elk sightings
- Very few elk bones found in archaeological sites in the park compared to other ungulates
- Very little evidence of elk browsing on vegetation in historical photos
- Elk are currently the most abundant ungulate species in the Canadian Rockies
- Today elk make up approximately 50% of the total ungulate population in Banff National Park
- Elk contributing to the decline of aspen stands in the park by over-browsing
- Wolf populations were systematically reduced by wolf control efforts from 1850 to the 1930s in large areas of the Canadian Rockies
- In the late 1940s, wolves were extirpated from Banff National Park as part of predator control efforts
- Wolf populations have slowly increased to 60-70 animals today in Banff National Park and surrounding areas
- Viable wolf populations are critical for keeping elk numbers under control
- Wolf populations are threatened by human caused mortality, habitat displacement, and loss of prey base
- Aspen clones established in Banff National Park 10,000 years ago following retreat of glaciers
- Since that time clones have regenerated by suckering from the root system following periodic fire
- Aspen stands in the park declining in abundance and vigour primarily due to heavy browsing by elk
- Under park management, aspen is moving toward ecological extinction
To preserve representative vegetation communities as mandated by Parks Canada, active ecosystem based management is required in order to duplicate the influence of native burning and hunting, fire history and predator-prey relationships that historically structured and maintained these ecosystems.