Monday, October 24, 2016

19-Oct-2016 Plain, Washington

Site location map. Click to enlarge.
It had been nearly three months since Rod Crawford and I were last able to align both of our schedules with the weather. Too long!  But finally all the pieces fell into place and we set out once again for another day of discovery.  Our destination: Plain, a small town on the east side of Stevens Pass, just southeast of Lake Wenatchee.  A dusting of snow on the upper reaches of Baring Mountain and Mount Index -- very unusual for this time of year -- was a visual reminder of the recent passage of Typhoon Songda through the area.

No room for spiders!
We made pine cone tapping the first order of the day's business, since vegetation and litter were still wet from rain or heavy dew the previous night.  With that in mind, we made our first stop on the unnamed forested pass between the Wenatchee River and Chumstick Creek valleys.  There were ponderosa pines galore (Pinus ponderosa) and plenty of cones, but for the most part the cones were still sealed.  They had apparently fallen from the trees prematurely.

Rod sweeping herbs under my pine
cone source in Plain.
We backtracked into Plain and drove through town in search of open, accessible cones.  The best cache of cones had been dropped into a shallow roadside ditch by a lone pine growing alongside the curiously named State Haul Road.

A typical fallen ponderosa
cone in Plain
Many of the fallen cones were dusty or muddy and fairly well decayed, and none had fully open scales.  And yet, a set of 50 tapped cones produced 19 spiders from 5 families.  Six species were identifiable, including Xysticus locuples (Thomisidae), Meioneta bucklei (Linyphiidae) and the undescribed Dictyna sp. #9 (Dictynidae), which we've mainly collected from fallen ponderosa cones or associated needle litter.  The most interesting spiders in this sample, however, were the three juvenile Zodarion, presumably Z. rubidum (Zodariidae).  We first confirmed the presence of this European species in Washington only this summer, from specimens collected in western Washington.  The present specimens are the first we've collected in eastern Washington.

Scots pine on a homestead in
Little Chumstick Creek valley
Fallen Scots pine cones
Our next collection site was located in the nearby Little Chumstick Creek valley.  A local homeowner gave us permission to collect on his property, which included an assortment of introduced tree species. Among them was a Scots pine (Pinus sylvestris), so naturally I tapped another round of fallen cones.  Many cones had been crushed by driveway traffic, but I was still able to find 30 undisturbed cones among the willow leaves and pine needles off to the side. I tapped 8 spiders and 4 species from those 30 little cones! Most were mature Tachygyna vancouverana (Linyphiidae), but a female Tenuiphantes tenuis (Linyphiidae) and a juvenile Enoplognatha ?ovata (Theridiidae) were also present. Together, these three species created a very familiar assemblage.  As Rod observed, this sample could have easily been tapped from cones in the Seattle conurbation in western Washington.

Read Rod's trip narrative here.
A female Helophora orinoma (Linyphiidae) tapped from a ponderosa cone
in Plain, Washington

Fall colors on the shore of the Wenatchee River near Plain, Washington
Rod sorting a sweep sample in the Little Chumstick Creek valley

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