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Ancient spiders from an ancient forest

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Ever wish you could travel back through time and see a west coast Vancouver Island rainforest before industrial logging? To see huge old trees, intact soils and life in a climax ecosystem? You do not have to invent a time machine, you only need to travel about an hour out of Port Renfrew to the spectacular Walbran Valley.

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As part of an effort to document the biodiversity of the valley, I traveled with fellow arachnologists Claudia Copley, Darren Copley, Zoe Lindo, and Catherine Scott, along with birders, mycologists, lichenologists and assorted volunteers to spend a day among the giant trees. We were there at the invitation of the Friends of Carmanah-Walbran to lend our expertise to the effort of catloguing the biodiversity of this beautiful, yet still at-risk west coast habitat.

We arrived at the somewhat storied “Bridge to Nowhere”, where in 1991 environmental protesters confronted the logging companies, the RCMP and the government of British Columbia, holding the line against industrial exploitation of a rare ecosystem. What the activists were asking for seems modest: Can’t we have just this one watershed, among all the others on Vancouver Island, be preserved and protected from the clearcutting and degradation that is the fate of every other valley on the Island?

20170528-IMG_00212. Pacheedaht elder Bill Jones walks across the Bridge to Nowhere

While the Friends of Carmanah-Walbran took the other participants deep into the woods on hikes, we arachnologists ventured only short distances into the woods, as our slow and careful sifting through the soil and beating of the bushes is certainly not a thrill ride for everyone. For us, however, it was thrilling, as within 30 minutes of arrival on site, we had found a beautiful and seemingly dense population of Hexura picea, a relative of tarantulas.

20170528-IMG_00803. Hexura picea, a tarantula relative, brought out of its underground silk tunnel complex for a photo shoot.

These little, pretty, but nondescript spiders live in small silk tunnel complexes among the soil and rocks of the forest floor. Each tunnel has a main entrance lined with silk, and several other openings which may facilitate rapid escape or offer alternate exits at which to snare prey. Being members of the suborder Mygalomorphae, they are indeed tarantula relatives, a group of spiders that closely resemble ancient spiders. Many mygalomorphs retain traces of segmentation on their abdomens, unlike the more modern araneomorph spiders. In the Mecicobothriidae (to which Hexura belongs) the terminal spinneret segments bear “pseudosegmentation”

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The section of forest we found this spider in was a real “tangled bank”, in fact the scree slope associated with Walbran creek and a small tributary, which has since been covered with a layer of soil and a stand of hardy trees.

20170528-IMG_00574. Erosion is a gentler process in a forested valley, with trees holding on to what would be a talus slope higher in the mountains. The soils beneath these trees support an extensive food web.

Finding these spiders in the Walbran was not unexpected, as they had previously been found in the Carmanah Valley and at Avatar Grove, but their presence on Vancouver Island is somewhat puzzling, as they represent the only known Canadian population, and are seemingly not present on the BC mainland.

Given the dense population in the Walbran, the valley would be an wonderful place to study their behaviour, which so far is undocumented. We would presume that much of the activity of these spiders takes place at night, although Catherine was able to lure one out of its burrow by tickling the silken doormat with a twig.

20170528-IMG_01115. Hexura picea emerges from its silken tunnel and onto its “doormat” to “kill” a vibrating cedar twig.

The litter sampling we conducted will surely yield many more species, although we have to wait until the Berlese funnels have extracted all of the arthropods. The work of sampling and cataloguing biodiversity takes time, and is not totally congruent with the rapid “bioblitz” ethos.

If you are ever in BC, and want a trip back in time (never mind our politics), please do not hesitate to come out to the Walbran Valley. You may just discover something amazing.

20170528-IMG_02486. Darren and Claudia picking up pan traps beside the Malaise flight-intercept trap.

 

 

 

 

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One comment on “Ancient spiders from an ancient forest

  1. […] a trip to the Walbran Valley, where we met up with an awesome tarantula relative Hexura picea. Read all about it here, and then check out these videos I took today of feeding specimens we brought back alive. They seem […]

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