Sensitive Ecosystems an indicator of biological diversity in the Georgia and Okanagan basins

What is Happening?

Ecologically significant lands and important wildlife habitats in the region are disappearing. This is of particularly great concern in the Georgia and Okanagan basins where plants and animals are losing their natural habitats to burgeoning development.

In the Georgia Basin

For East Vancouver Island and Gulf Islands, a Sensitive Ecosystems Inventory (SEI) was conducted between 1993 and 1997. The inventory documented that less than eight percent of the eastern coastal lowlands of Vancouver Island and the Gulf Islands still supports rare and fragile ecosystems.

This SEI was the first of its kind in British Columbia and was an outcome of the commitments made by the federal and provincial governments to the Canadian Biodiversity Strategy. A Sensitive Ecosystems Inventory distinguishes between sensitive ecosystems and other important ecosystems. "Sensitive ecosystems" refer to relatively unmodified rare and fragile ecosystem remnants critical to the survival of the species it supports. The East Vancouver Island and Gulf Islands inventory which extended from Sooke to north of Campbell River identified seven sensitive ecosystems. These include riparian, wetland, woodland, older forest, sparsely vegetated, terrestrial herbaceous and coastal bluff ecosystem types (see Table for descriptions of ecosystems). Because of the ecological roles they perform and the genetic diversity they contain, tracking their status serves as a useful indicator of biological diversity or natural capital.

As can be seen in the pie chart, the majority (92.1%) of the East Vancouver Island and Gulf Islands study area's landscapes have been modified. The seven sensitive ecosystems cover the remaining 7.9%. Older forests, an ecosystem that once dominated the landscape, now cover less than three percent (10,605 ha) of the coastal lowlands. Riparian ecosystems occupy only 1.6% (6,713 ha) of the inventory area. Wetland ecosystems account for 1.7% (7,054 ha). Sparsely vegetated ecosystems are the rarest of the sensitive ecosystem types covering less than 0.1% (344 ha). Terrestrial herbaceous ecosystems total only 1% (4,243 ha) of the land base. Coastal bluff ecosystems are naturally rare occupying about 0.3% (1,043 ha). Woodlands are one of the most threatened of the sensitive ecosystems, covering only 0.6% (2,519 ha).

Inventory results were tabulated based on the primary ecosystem type although in approximately 20% of the sites more than one ecosystem was present. The Sensitive Ecosystems Inventory for East Vancouver Island and Gulf Islands was conducted by several participants.

The Garry oak ecosystem, part of the woodland sensitive ecosystem, is a mix of trees, meadows, grasslands and open rocky areas that harbor many rare and endangered species which are dependent on it. From 1850 to 1950, much of the land containing Garry oak was logged or converted to farms. The original historical distribution of Garry oak ecosystems believed to exist in 1800 and that remain in existence in the 1990's has been mapped for Greater Victoria and Saanich Peninsula. Overall, less than five percent of the original Garry oak habitat remains; all of it in the Georgia Basin.

Because of the continuing development pressure, the BC Ministry of Water, Land and Air Protection (BCWLAP) conducted an audit of sensitive ecosystems identified in the SEI (Caskey and Henigman 2002). Of some 2000 sites audited, approximately 11% showed a measure of some disturbance over the past 6-8 year period. Of the seven sensitive ecosystems, the greatest level of disturbance was in Older Forests. Because the disturbances were not quantified, the area of sensitive ecosystems lost is not known. However, this trend is worrisome. If the present rate of disturbance continues, all remaining natural sensitive ecosystems could be impacted within the next few decades. This would result in a loss of biodiversity on East Vancouver Island and Gulf Islands.

An SEI on the Sunshine Coast from Howe Sound to Desolation Sound (including adjacent islands) is also being conducted by several participants. Although there are no results yet from this inventory, the concern is that the rare and fragile terrestrial ecosystems of these coastal lowlands are becoming more rare.

Wetland Inventory

In 1989 Environment Canada's Canadian Wildlife Service undertook to inventory the wetlands of the Fraser Lowland (Ward 1992). At the time 41,906 hectares (ha) of wetland were left in the study area, representing 13.6% of the total area (309,200 ha) of the Fraser Lowland. Nearly two-thirds (64.4%) was accounted for by the "shallow water" wetland class, most of which was comprised of large tidal flats at the mouth of the Fraser River and in Boundary Bay. The other third included 14.6% marsh, 7.5% gravel bar, 5.7% fen, 4.5% bog and 3.4% swamp. About 72% of the wetland area in the Fraser Lowland was given the highest of a three-level rating system, i.e. "undisturbed". Excluding the tidal flat category ("shallow water" wetland class), 60% of the remaining wetland area had the highest rating. A review of urban and agricultural encroachment into wetlands between 1989 and 1999 was conducted by the Canadian Wildlife Service. Of 320 wetlands assessed, 22% experienced some degree of encroachment resulting in a loss of 965 hectares of original wetland area. As shown below, most of the area lost was due to agricultural development (41%), golf courses (25%) and landfill expansion (16%).

The concern is that the wetlands in 1989/1999 were already just remnants of what was in the Fraser Lowland prior to European settlement. A research project documenting changes in land cover in the Lower Fraser Basin found that wetlands in that study area had decreased about 85% between 1827 and 1990 (Boyle et al. 1997).

One of the largest wetlands in the inventory is Burns Bog. Located in the Fraser River delta between the south arm of the Fraser River and Boundary Bay, the Bog's wetland ecosystem is globally unique because of its large size and the plant communities it supports. Forty percent of the original bog area has been altered by development; placing even greater importance on the remaining bog ecosystem. Many of the wetlands identified in the inventory were protected by such initiatives as the Lower Mainland Nature Legacy and the Pacific Estuary Conservation Program.

In the Okanagan Basin

An SEI has just been completed in the Central Okanagan. Inventory results showed that sensitive ecosystems occupied twenty-eight percent of the study area. Wetlands and old forests are extremely rare in the area. Wetlands are naturally rare in this landscape, but many have been filled in or significantly altered. Old forests historically would have occupied the majority of the landscape, and almost no old forest remains (0.06%). Grasslands have been converted to agriculture and developments and many have become invaded with weeds. Disturbed Grasslands are grasslands with introduced species comprising more than 50% of the vegetative cover. More than half of the grasslands mapped on deep soils fall into this category. Riparian areas are still more common, however, the continuity of riparian corridors has been disrupted in many places and many riparian ecosystems have become degraded through channelization, vegetation removal, and other disturbances. Although many areas of conifer woodlands and mature forests remain, many have been altered significantly through selective logging and fire exclusion and few high quality sites were found by participants of the Central Okanagan Sensitive Ecosystems Inventory.

In the South Okanagan considerable detailed inventory work has been done, and a project is currently underway to convert the data into an SEI map in 2003. The key habitats include the wetland/riparian, grassland/shrub-steppe, coniferous forest, and rugged terrain types. These natural systems are restricted to a narrow trough comprising 160,000 hectares from Summerland and Naramata on Okanagan Lake south to Osoyoos on the Canada-U.S. border. Nearly half the bird species in Canada are found here along with many plants and animals that exist nowhere else in North America or, in some cases, the world. For example, fifteen of the 20 species of bats found in Canada are in the Okanagan Valley and the Pallid Bat is found nowhere else in Canada.

The wetland and riparian habitats have suffered the greatest loss and have reached a critical point. The grasslands/shrub steppe have been dramatically altered by human settlement. The fragile desert grasslands of the South Okanagan are home to about one-third of BC's endangered, threatened and vulnerable species.Two species of songbird, the Yellow-breasted Chat (dependent on riparian habitat) and the Sage Thrasher (dependent on Sagebrush and grassland complexes) are nationally endangered because of low numbers and habitat loss. In addition to monitoring these birds as useful indicators of the health of these two sensitive ecosystems the Canadian Wildlife Service is also leading the development of recovery strategies.

In the coniferous forests only a few patches of old-growth Ponderosa pine, Douglas-fir, and western larch forest remain. The old-growth Ponderosa pines are vital habitat for the White-headed Woodpecker, an endangered species whose only Canadian home is here. The rugged terrain with its magnificent cliffs and rocky talus although less damaged than the other habitat types is being threatened by urbanization and recreation activities.

Why is it Happening?

In the Georgia Basin

The east coast of Vancouver Island and the Gulf Islands are experiencing one of the highest rates of population growth in BC. Between 1991 and 2002 the population increased by 17% with almost 652,000 people currently living in this area. This rapid growth has resulted in the loss of sensitive ecosystems through conversion to other land uses or by degradation from human use and invasion by non-native plants (such as Scotch broom and Purple loosestrife) and animals (such as gray squirrels). Human activities have altered more than 90% of the original landscape.

During this same time, the population of the Lower Fraser region increased by 29% to almost 2.4 million people. Rapid development along the coastal lowlands of the Sunshine Coast is also resulting in the fragmentation and degradation of those ecosystems which include vulnerable and threated plant communities. Between 1991 and 2002 the population of the Sunshine Coast increased by 27% to almost 78,000 people.

Source: BC Stats, 2003. The Lower Fraser River population includes the Fraser Valley and the Greater Vancouver Regional Districts. The Sunshine Coast population includes the Sunshine Coast and Powell River Regional Districts and the Howe Sound Local Health Area.

In the Okanagan Basin

Similar losses of sensitive ecosystems have occurred in the South Okanagan-Similkameen as a result of population growth and its accompanying urban and intensive agricultural development, use of off-road vehicles, dyking and drainage, introduced species (such as knapweed), livestock grazing, and fire suppression. Between 1991 and 2002 the population of the Regional District of the Okanagan-Similkameen increased by 18% to almost 81,000 people. During this period, similar growth in population was observed in the other Regional Districts of the Basin producing a Basin wide population increase of 27% to almost 314,000 people.

Why is it Significant?

Since some ecosystems support species not found elsewhere, preserving them is necessary in order to protect genetic diversity. Habitat viability and integrity is fundamental to conserving biodiversity. Because of the variety of living organisms (humans as well) that they support and the ecological roles they perform, sensitive ecosystems are major components of the ecological diversity of an area. When the diversity of ecosystems falls so does biological diversity. We depend on biological diversity for our foods, medicines, and other raw materials we use. Further losses of sensitive ecosystems therefore represent an erosion of sustainable biodiversity and is a national concern. Additional benefits to be lost include recreational and learning opportunities.

In the Georgia Basin

The east coast of Vancouver Island and the adjacent Gulf Islands form a unique ecological region in Canada. The mild climate and long growing season supports many rare species of plants and animals, and plant communities. It is one of three areas in BC, the others being the Lower Fraser River and the South Okanagan, where the greatest loss of natural systems is occurring. In each area, intense development pressures are resulting in the fragmentation, degradation, and loss of "sensitive ecosystems". The destruction of these natural habitats in turn leads to the loss of plant and animal species.

As an example, Garry oak woodlands are one of the four most endangered ecosystems in Canada. Garry oak ecosystems contain 93 species of mammals, reptiles, birds, insects, butterflies, mosses and plants that are listed as endangered or threatened in British Columbia. Of these species, 18 are listed by The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as being at risk nationally. By conserving environmentally significant features and ecosystem functions, the integrity and biodiversity of regional ecosystems is protected for future generations.

In the Fraser River delta, more than half the remaining area of Burns Bog has been disturbed by human activities. Surrounding urban, industrial and agricultural development has led to the Bog's isolation. An ecosystem report prepared by the BC Government's Environmental Assessment Office identifies several nationally and provincially listed species of wildlife that reside in the Bog along with unique plant communities and a variety of rare insect species. The report recognizes Burns Bog as an area of global, national, provincial and regional significance. In March 2004, a final agreement between the Government of Canada, the Province of BC, the Greater Vancouver Regional District (GVRD) and the Corporation of Delta was reached to acquire and preserve Burns Bog.

The importance of sensitive ecosystems is also evident in other ways. Protecting sensitive ecosystems also creates economic benefits. The Brant Festival in Qualicum Beach is a good example of how the local economy benefits directly from the conservation of the foreshore tidal habitat that Brant Geese are dependent upon. The two day event, in 1993, brought in over $400,000 to the local area.

Sensitive ecosystems may have limited adaptive capacity and are therefore particularly vulnerable.With temperature increases already documented for the region (see Climate Change Indicator) these sensitive ecosystems may be directly impacted by the effects of climate change. The impacts may also be the result of indirect effects such as the altered hydrology of a wetland area. In a few cases however, a warmer and drier climate could favour certain sensitive ecosystems like the Garry oak which historical evidence has associated with a warmer climate.

In the Okanagan Basin

In the South Okanagan-Similkameen, 23 species of plants and animals are currently listed as nationally threatened, endangered or of particular concern and one-third of provincially red-listed species, make their homes there. Over half of these species depend on the sensitive ecosystems of this region. For example, the grassland/shrub-steppe ecosystems are vital habitat for more than half the species at risk. Wetland/riparian habitats are important to one of only two viable sockeye salmon runs in the entire Columbia River watershed. The woodlands of the coniferous forest and the rugged terrain provide crucial habitat that supports species found in no other habitat type. Overall the area is recognized as one of the nation's most endangered natural systems.

What is Being Done?

In the Georgia Basin

Recognizing the plight of sensitive ecosystems, Environment Canada combined resources with numerous participants to conduct the Sensitive Ecosystems Inventory for East Vancouver Island and Gulf Islands. The SEI is a "flagging" tool that identifies the remaining fragments of these natural ecosystems and provides information that can be used in working to maintain biodiversity. The database and maps are being updated and will be available by late 2003 or early 2004.

The SEI maps and other outreach services and materials are intended to encourage land-use decisions that will ensure the continued integrity of these ecosystems. SEI maps are available for viewing through local municipal or regional planning offices, through the Ministry of Water, Land and Air Protection or Environment Canada. They can be used to determine whether or not the proposed activity is in or near a sensitive ecosystem. The accompanying SEI Manual offers practical advice to local and regional governments, landowners and other citizens, on how to best avoid or minimize damage to them. Policies and guidelines are also offered as models for use in Official Community Plans and Development Permits. A descriptive pamphlet for each sensitive ecosystem with recommendations on how to protect it have also been published for use by local governments, non-government organizations and interested individuals. The SEI information has already been used by local governments in developing or revising Official Community Plans and for land -use planning exercises such as the Capital Regional District's Green and Blue Spaces Strategy.

As part of a global commitment to conserving biodiversity, at the 1992 United Nations Conference on the Environment and Development over 160 nations agreed on a Global Convention on Biodiversity. There is a recognition at most levels of government for the need to protect the remaining biological diversity within their jurisdictions. At local levels many community plans and growth management plans have included goals to protect environmentally significant features and sensitive ecosystem functions. Examples are the Regional District of Nanaimo's Growth Management Plan and the Mount Arrowsmith Biosphere Reserve supported by the communities of Qualicum Beach and Parksville.

In an ongoing effort to protect the remaining sensitive ecosystems of Vancouver Island and the Gulf Islands, Environment Canada has partnered with local agencies under the Georgia Basin Ecosystem Initiative. The Georgia Basin Ecosystem Conservation Partnership led by Environment Canada established a consortium of government and conservation organizations that has developed a catalogue of ecologically significant sites within the Georgia Basin for acquisition or stewardship actions. A joint acquisition project together with The Land Conservancy of British Columbia and the Capital Regional District protected a total of 1380 hectares in the Sooke Hills area. Six hectares were secured at Mill Hill Regional Park, near Langford. Partners in the acquisition included the Capital Regional District and the Nature Conservancy of Canada. On Galiano Island, twelve hectares of coastal bluffs were purchased. The Islands Trust Fund, The Land Conservancy of British Columbia and Habitat Acquisition Trust helped acquire these lands (see News Release) to protect both the Garry oak ecosystem and important nesting habitat for seabirds which are also monitored as an indicator of ecosystem status. The purchase of old-growth forests on Saltspring Island by the Provincial and Federal governments together with the Capital Regional District and community of Salt Spring have also helped preserve some rare stands of intact Garry oak woodland and associated ecosystems. The Garry Oak Restoration Project partnered with the Municipality of Saanich, the Garry Oak Meadow Preservation Society and the University of Victoria has several restoration sites within Saanich. GBEI partners together with The Nature Trust of BC have also contributed funds to develop an overall management plan for Garry oak ecosystems.

On May 9, 2003 the Governments of Canada and British Columbia established the new Gulf Islands National Park Reserve covering about 33 km² scattered over 16 islands in the southern Gulf Islands. The Park Reserve will protect these threatened and fragmented ecosystems and contains the highest number of species at risk of any park in the Parks Canada system.

Elsewhere in the Georgia Basin, work is almost complete on the Sunshine Coast Sensitive Ecosystems Inventory. Results will be released in 2003. This is a multi-year project designed to systematically inventory the remaining sensitive (rare and fragile) terrestrial ecosystems of the Sunshine Coast and islands in the northern Strait of Georgia. The purpose of this SEI is to provide scientific information and support to planners and local governments for use in Official Community Plans, Growth Management Strategies and Parks Plans.

In the Okanagan Basin

Environment Canada together with Parks Canada Agency and Fisheries and Oceans Canada coordinate a Habitat Stewardship Program dedicated to improving the survival prospects of identified species at risk. Under this national Program, $1.5 million of $10 million available in 2002 was allocated to BC. Over $600,000 was directed to the Environment Canada led South Okanagan -Similkameen Conservation Program which focuses on habitat restoration and wetland and grassland stewardship. Environment Canada has encouraged community involvement in the Program by non-government organizations, private landowners, conservation groups, local governments and First Nations. For example, the Osoyoos Band is helping to preserve some of the last undeveloped and unfragmented desert habitat located on their reserve lands. The Program was formed in July 2000 to coordinate the efforts of government agencies and conservation groups. It's goal is to protect the critical habitat corridor which links the deserts to the south and the grasslands to the north. It has an active land acquisition program which is purchasing key properties to contribute to landscape preservation and species recovery. The Program's partners believe that preserving this area depends on finding a balance between protecting wildlife and human needs.

The sensitive ecosystems inventory work contributes to an Okanagan-wide conservation strategy. The Central Okanagan inventory is a partnership effort between the Regional District of Central Okanagan, the Ministry of Sustainable Resource Management (formerly the Ministry of Environment, Lands and Parks - Resources Inventory Branch, Wildlife Inventory Section and the BC Conservation Data Centre) with additional contributions from the Habitat Conservation Trust Fund. The South Okanagan inventory work complements an already completed "Habitat Atlas for Wildlife at Risk" in the South Okanagan and Similkameen.

To meet the emerging environmental crisis of reduction and fragmentation of natural habitats in the South Okanagan, a total of 31 conservation organizations, government agencies and community partners now participate in the South Okanagan-Similkameen Conservation Program. Program activities are being directed at the four key habitats: wetland and riparian, grassland/shrub-steppe, coniferous forest, and rugged terrain. The Program aims to maintain the rich biodiversity of the area by employing both hands-on rehabilitation efforts and land-use planning tools.

A South Okanagan-Similkameen Valleys Ecosystem Recovery Strategy is also in development to detail the recovery actions required for the multiple species at risk. This strategy is complimentary to the South Okanagan-Similkameen Conservation Program goals and objectives.

Future Actions

Future actions of the Sensitive Ecosystems Inventories will encompass a comprehensive evaluation of the effectiveness of the Vancouver Island and Gulf Island SEI, including analysis of remaining habitat as well as an assessment of the level of influence an SEI has on land-use decisions. Public outreach programs are planned for the Sunshine Coast and Central Okanagan in 2003. The greater the number of sensitive ecosystems that are preserved, the greater our success will be at conserving biodiversity in general and species at risk in particular. The long-term conservation of biodiversity depends not only on governments, landowners and developers but also on public support for the conservation effort.

For more information on East Vancouver Island and Gulf Islands and Sunshine Coast SEI projects contact Jan.Kirkby@ec.gc.ca, for the South Okanagan Trish.Hayes@ec.gc.ca and for land acquisitions Michael.Dunn@ec.gc.ca.

Check the following sites for additional information on this indicator:

• Species at Risk
• Canadian Wildlife Service
• Garry oak ecosystems and an article on "Investing in the Future"
• Canada's Endangered Desert Country
• Canadian Wildlife Service - Ecological Gifts Program
• Parks Canada and the Gulf Islands National Park Reserve of Canada

The following Web sites are not under the control of Environment Canada (EC) and they are provided solely for the convenience of users. Environment Canada is not responsible for the accuracy, currency or the reliability of the content. Environment Canada does not offer any guarantee in that regard and is not responsible for the information found through these links, nor does it endorse the sites and their content. Users should be aware that information offered by non Government of Canada sites that are not subject to the Official Languages Act, and to which Environment Canada links, may be available only in the language(s) used by the sites in question.

• Sensitive Ecosystems Inventories in British Columbia
• Visit the East Vancouver Island and Gulf Islands Sensitive Ecosystems Inventory for publications available in PDF format - Conservation Manual (2.3 MB PDF) and "Saving Sensitive Ecosystems" brochures - Coastal Bluff Ecosystems (801 KB PDF) - Sparsely Vegetated Ecosystems (823 PDF) - Terrestrial Herbaceous Ecosystems (815 KB PDF) - Wetland Ecosystems (762 KB PDF) - Riparian Ecosystems (828 KB PDF) - Woodland Ecosystems (790 KB PDF) - Older Forest Ecosystems (822 KB PDF). Also available is 12 page brochure, "Our Living Legacy" (907 KB PDF) designed for landowners, developers, planners, advocacy groups, politicians and scientists, about the scarcity and value of the remnant natural areas on Vancouver Island's eastern coastal lowland and Gulf Islands.
• Sensitive Habitat Inventory and Mapping (SHIM)
• Garry Oak Meadow Preservation Society
• Habitat Conservation Trust Fund
• A Donor's Guide for BC containing information about the incentives for ecological gifts of land or covenants

For references used in this indicator click here.