Ecoregions of Coastal British Columbia
British Columbia has greater diversity in landform and climate than any area of comparable size in Canada. The variety in these two key geographic elements, together with the large size of the province, its maritime location, and its spatially intermittent glaciation, are responsible for the province’s high biological diversity at the gene, species and ecosystem levels.
In order to ensure that the full spectrum of today’s biodiversity is conserved for tomorrow’s generations, we must act now to complete a system of protected areas.
In a perfectly rational world, we would develop an adequate protected area system based on a complete database. We would know all of the species that exist in the province. (It has been estimated that only about half of BC’s unique insect species have been identified and named). We would have a watershed-by-watershed inventory of species and subspecies. We would know, for the larger animals, their range and the minimum population size needed to avoid loss of genetic variability, which could threaten the species’ survival. We would know the degree of sub-speciation of tree species and the rate of their gene flow from watershed to watershed.
Given this information, we could then study our system of parks and protected areas to determine if all of the province’s biodiversity is adequately represented, and where gaps in current representation exist. Then we could select areas for protection which would best “fill in” the gaps.
Unfortunately, our knowledge today is unbelievable rudimentary. In coastal BC, for instance, we currently have little understanding of even the threatened species such as the marbled murrelet. Whole new communities of insect species were discovered only this summer in the canopy of the Carmanah forest on Vancouver Island. The process of studying our natural wealth in all its diversity must become a priority immediately. The government of BC is beginning to realize this, and, with the help of the Nature Trust, has set up a provincial conservation data centre.
Yet, we cannot wait until all of the information is in, for, at the present rate of industrial development, all of today’s wild areas – and the opportunities to protect our biodiversity – will have long been developed before we have learned what we have lost.
We have no choice. With the limited information that now exists and the general biogeographical classifications which have already been developed, we must begin to analyze the adequacy of our current protected area system.
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Several efforts have been made to classify BC’s ecosystems into units for the purposes of systematic study and management. V.J. Krajina, together with his colleagues and students at the University of British Columbia, developed a Biogeoclimatic ecosystem classification that has been adopted by the BC Ministry of Forests and most forest companies. D. Demarchi of the BC Ministry of Environment developed an Ecoregion classification for BC to provide a regional physiographic and climatic context to the biophysical framework. The Ministry of Parks has also developed a system of classification which divides the province into 59 Landscapes.
The temperate rainforest is defined in the biogeoclimatic classification system as the area within BC in the Coastal Western Hemlock (CWH) and Coastal Douglas Fir (CDF) biogeoclimatic zones. The extent of the diversity in this area is better reflected in the Ecoregion classification system, for those two biogeoclimatic zones extend through two Ecoprovinces (Coast and Mountains and Georgia Depression), which are subdivided into 12 ecoregions. Some of these ecoregions are further subdivided into ecosections, resulting in a total of 18 regional units.
The map and tables on the next page analyze undeveloped watersheds within the temperate rainforest zone by these Ecoregion units. The most startling finding from this comparative study is that only 7 of the 16 ecoregions – all of which once contained wild primary watersheds greater than 5,000 ha – still do today. In more than half of our temperate rainforest ecoregions we have already lost the chance to protect whole wilderness watersheds!
