Climate change calls for land-use plan rethink

Special to the Times Colonoist,
Chris Genovali,
July 21, 2009

The spectre of rising sea levels and ecological change from climate disruption show land-use plans for Vancouver Island and the B.C. coast will need to be revisited and recalibrated to account for rapid and unabated climate change.As reported in the journal Science in March, sustained atmospheric warming projected for the coming centuries could ultimately produce a worldwide rise in sea level of 12 metres compared with today’s levels.

In the shorter term, it is currently estimated there will be more than a one-metre rise by 2100, which would have a significant impact on coastal environments.

All levels of government need to be thinking about adaptation, resilience and dynamic management; unfortunately, current static land-use plans for coastal B.C. do not allow for this.

“Once set in motion, sea-level rise is impossible to stop. The only chance we have to limit sea-level rise to manageable levels is to reduce emissions very quickly, early in this century. Later it will be too late to do much,”says senior NASA scientist Stefan Rahmstorf in a recent article for the United Nations Office for the Co-ordination of Humanitarian Affairs.

Given the recalcitrant posture of greenhouse gas-producing industries, the reluctance of governments to act and the general ambivalence among the public to alter a comfortable carbon-based lifestyle, the odds would appear to be stacked when it comes to reducing emissions at the pace required to contain a rise in sea levels.

Sea-level rise poses a major threat to fish and wildlife throughout the B.C. coast as estuarine health and wetland survival will be put at risk. Pacific salmon are estuarine-dependent and estuaries depend on wetlands to maintain water quality. As salmon move between fresh water and saltwater, they rely on both coastal and riverine wetlands to successfully complete their life cycle.

The U.S. Global Change Research Program has forecast that climate change is very likely to substantially alter the distribution and abundance of fish stocks, which has important implications for marine populations and ecosystems.

The program predicts that “changes over the long term are likely to include poleward shifts in distribution of marine populations, and that with changing ocean temperatures and conditions, shifts in the distribution of important species are likely.”

For example, research now suggests that several species of Pacific salmon are likely to have reduced distribution and productivity, which could, in turn, have severe results for terrestrial ecosystems.

Raincoast Conservation carnivore ecologists Chris Darimont and Paul Paquet have written that “although salmon spend a significant portion of their lives in the marine environment, they also inhabit and dominate the aquatic portion of the terrestrial landscape, where they comprise the largest seasonal influx of available biomass. This biomass feeds dependent wildlife and provides nutrient pulses to terrestrial and freshwater processes. As such, salmon are a foundation species upon which coastal ecosystems are built.”

Darimont and Paquet further explain that the health and abundance of coastal grizzly and black bear populations are closely linked to salmon abundance. This is likely the case for other terrestrial carnivores such as wolves,otters and mink.

Their primary point is that salmon are not exclusively marine organisms and considerations about terrestrial conservation in a coastal environment are incomplete when the ecological influences of salmon are ignored.

A robust network of protected areas that are free of other stresses provides one of nature’s best opportunities to adapt to climate change.

However, conservancies within the Great Bear Rainforest were chosen on an ecosystem representation basis and park designations on Vancouver Island were established via political negotiation in which science had no meaningful role.

Because these ecosystems are unlikely to remain stable in a climate-altered future, parks and protected areas should be re-assessed based on connectivity and migration corridors — and that includes marine migration corridors for salmon.

Climate change can drive species into new habitats, which could have serious ecological consequences. Habitat shifts are predicted to occur with latitude and with altitude. This means a loss of habitat for some plant and animal species and a gain for others.

Recognizing that animals and plants thrive best within intact ecosystems, not arbitrary borders, it would be prudent to secure biological corridors where animals can roam freely among protected areas as they adapt to a changing environment.

Chris Genovali is Executive Director of Raincoast Conservation.

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