fatehbaz:

Subterranean streams in karst cave systems provide for sustained biodiversity in old-growth rainforest of Vancouver Island - and due to a 2014 forest fire, researchers now see the cave systems as far more important than previously recognized

This is a “karst window” on Vancouver Island, a feature that occurs when subterranean streams temporarily reemerge on the surface. This photo also features Dr. Carol Ramsey, a prominent local researcher of karst systems. [Photo by Grant Callegari and publicized by journalist Bruce Grierson.]

Dr. Ramsey joins another prominent local scientist, Dr. Paul Griffiths. [Photo by Grant Callegari, publicized by Bruce Greirson.]

Diagram of karst cave system. From McColl, K. M. et al. (2005) Geoscape Nanaimo, geoscience for central Vancouver Island communities. Geological Survey of Canada, Mischellaneous Report 87.

Dr. Ramsey inspecting a karst cave entrance. [Photo by Grant Callegari, via Bruce Grierson.]

In 2014, a forest fire ravaged an area of extensive clear-cutting at Kinman, in the Hankin Range of northern Vancouver Island. Since the fire cleared the forest floor of moss, stumps, and debris, a hidden and enormous limestone karst formation was exposed.

This kind of karst ecosystem is pretty common on Vancouver Island. Though, this recent exposure provided new research opportunities for the several ecologists and geologists who have specialized in studying the island’s caves for the past few decades.

This is a photo of the Kinman area, where the 2014 fire exposed extensive karst. [”Reporter Larry Pynn stands atop a charred old-growth stump within a karst limestone landscapes …” Vancouver Sun, 2018.

Researchers Ramsey and Griffiths feature prominently in recent reporting on karst systems. Here’s an excerpt from the Vancouver Sun: “Globally significant karst and old-growth ecosystems at risk on Vancouver Island.” Larry Pynn - 19 March 2018.

Clear cool streams once flowed through humid old-growth forests rich in lifeforms on northern Vancouver Island. Today, the site is a virtual dead zone, fireweed poking through the rubble the only sign of life.

In 2014, a wildfire swept through the Western Forest Products clearcut, high above Nimpkish Lake, and the thin layer of soil disappeared through fissures and openings in the limestone karst.

Ironically, the only thing that stopped the fire was a patch of old-growth trees that Western had not cut down. The standing rainforest lacked the dry wood debris left behind after logging that fueled the fire.

“It’s a different microclimate under the canopy of an old-growth forest,” explains B.C. karst expert Paul Griffiths. “You get a few downed trees, but generally they are moss covered.”

The fire burned 165 hectares, an estimated 89 hectares of that over karst.

Karst is a fragile type of topography that develops when water dissolves soluble bedrock — predominantly limestone on Vancouver Island, a Canadian hot spot for karst. The gradual process can form caves or caverns, passageways, creeks and springs, sinkholes, and fantastic but easily damaged speleothems such as columns, curtains, flowstone, soda straws, stalactites and stalagmites.

Karst also makes for more productive rainforests, draining away extensive rainfall while the dissolved cracks in the bedrock give tree roots a good foothold against powerful winter winds. Karst also reduces the acidity of rainfall, providing improved habitat for aquatic life, including resident and migratory fish.

Researchers Griffiths and Carol Ramsey have been fighting for years for better protection of karst landscapes on Vancouver Island, especially those associated with old-growth forests.

Griffiths describes this particular karst area as “very significant,” arguing it should not have been extensively clearcut. The fact that it was with no apparent attempt to protect karst features highlights the need for the province to improve the level of protection and ensure in-the-field inspections.

[Source.]

A “karst spring” - where subterranean water feeds back onto the surface - near Port Aberni. [Source.]

“Rare and endangered species dwelling in the karst cave systems, such as the Quatsino Cave Amphipod (Stygobromus quatsinensis), are completely dependent on dissolved nutrients transported by the water.” [Charly Caproff, for Sierra Club BC.]

-

A “karst spring” - this subterranean flow reemerges from a karst channel to join the Walbran River. [Source: Sierra Club BC and Charly Caproff.]

-

Extensive karst cave systems on Vancouver Island act as subterranean microhabitat that feeds old-growth rainforest on the surface

Reid Robinson, known locally as “the Karst Man,” in a photo for an article by Rikki Ayers for Sierra Club BC. “He has spent the majority of his life working in the forestry and fisheries industries and it wasn’t until he began working in tourism that he realized the intrinsic beauty of karst and how it was severely threatened by forestry and other resource industries.”

-

Activist with supportive sign, Vancouver Island [Photo by Sierra Club BC.]

-

Some of the best reporting on recent karst research on Vancouver Island comes from Bruce Grierson, available here.