By Mark Worthing
This article was originally published in Island Parent Magazine.
Have you ever hiked through the forests of Vancouver Island and come across rivers bursting out of the ground from seemingly nowhere? Or have you followed the path of a creek to find that the rushing water disappears underground? If you have, you’re likely walking on a karst landscape with a complex cave system of limestone, dolomite or marble beneath your feet.
Vancouver Island has more caves than all of Canada combined. These caves are a result of the large limestone deposits that span along its length. Where this soluble rock is exposed to rainwater or to the surface of the earth (epikarst), we call this a karst landscape.
Thousands upon thousands of years of rainwater carves the bedrock through alchemy and time. This forms the magical architecture of underworld sinkholes, caverns, caves and disappearing rivers. This phenomenon happens to correlate with Vancouver Island’s spectacular ancient rainforest.
If you were to take a flight above a karst forest, you’d see a richer colour in the forest canopy. The most productive salmon-bearing streams in coastal B.C. feature karst somewhere within their river system. These limestone deposits have the same basic chemistry as coral reefs, oyster shells, eggshells and antlers.
After the last Ice Age, rich nutrients were left behind by receding glaciers. These provided the food today’s old-growth trees needed to develop into some of the planet’s most unique and magnificent forests. Over time, that fertile topsoil has been sucked up into the trees and other plants, carrying on the lifecycle of ancient forest ecology. This has helped create towering nutrient-rich cedar, spruce and Douglas fir trees with roots clutching coral limestone bedrock.
This gift of glacial nutrients only comes once. It now exists only within the decomposition cycles of dead plant matter and fungus on the spongy forest floor. The topsoil has also been pulled down into valley bottoms and waterways, creating healthy salmon-bearing rivers and exposing the karst bedrock below.
When a karst landscape gets this nutrient gift, one of the most endangered ecosystems on Vancouver Island is created: old-growth karst forests.
Unlike Alaska and Washington where there is stringent protection, British Columbia has absolutely no legislated protection for karst landscapes or even caves. A Cave Protection Act has been tabled for first reading in the B.C. Legislature more than once and the U.S. federal Cave Resources Protection Act was made into law over three decades ago. Yet the logging industry’s death grip on the provincial government seems to block attempts for legislation. Karst or cave protection might damper logging companies’ profit margins, so there is little political will to regulate.
There is also no protection for rivers or creeks that ‘disappear’ underground. Logging and road building is legal on top of areas that could be massive cave and karst systems. Not only is this dangerous to workers and a risk to public health, but it is belligerent negligence of a fragile ecosystem.
The logging culture on northern Vancouver Island is extremely cavalier, which is unfortunate as the north end of the island has the most caves and karst landscape features. The legendary Maquinna Cave near Tahsis has had its entrance covered and desecrated with logging and road-building debris. Logging-caused slides near Holberg have flooded out entire cave systems and clogged water drainage systems older than the country of Canada.
The forest of the Walbran Valley and northern Vancouver Island’s East Creek sit on top of karst limestone. Within the Flathead Valley of B.C.’s southern Rockies lies the deepest cave systems in North America. All of these cave systems are vulnerable without legislated cave or karst protection.
Yet there is hope for these magnificent places. First Nations leaders are asserting sovereignty over their lands and sacred cave sites. The Horne Lake Caves boast 17,000 visitors per year, and they recently received Destination B.C.’s first-ever Remarkable Experiences Award. Through ecotourism and parks, the public is becoming more and more engaged with the fascinating and fragile world below the roots of the ancient forests of Vancouver Island. So get out there and explore!
Feature image by Charly Caproff.