Saturday, August 5, 2017

30-July-2017 Ferbrache Unit, Washington

Site location map. Click to enlarge.
With choices of productive sampling sites dwindling rapidly due to summer heat and dryness, Rod Crawford and I returned to a favorite late-season region, Grays Harbor County. Our main collecting site had the interesting name Ferbrache Unit, which I kept confusing in my mind with Fibonacci, as in the mathematical sequence. The area consists of Chehalis River sloughs, forest remnants and agricultural fields managed for waterfowl. My source of fallen cones was the one and only Sitka spruce (Picea sitchensis) growing on the forested edge of one such grassy field.

Rod dwarfed by the Sitka spruce and
its encircling jungle.
Looking across grassy field
at the giant Sitka spruce.
The tree was a giant and sported a massive skirt of Himalayan blackberry (Rubus armeniacus) and coastal manroot (Marah oregana or M. oreganus). The latter resembles the edible cucumber and belongs to the same family (Cucurbitaceae), but is apparently not edible.

First set of tapped cones returned
to the grassy field
Numerous cones had fallen on the grassy field, so I tapped 57 of them while Rod beat the few reachable spruce branches and the tree's skirt of foliage. My efforts resulted in only one juvenile spider.

Fallen cones near tree base made up
the second set
By the time I was done with that first set of cones, Rod had made a big enough hole in the wall of green (a machete would have been useful!) for me to worm my way through to the trunk of the tree.

Inside the manroot tangle
I was pleased to find vast quantities of cones under the pleasantly green and less-dry tree canopy and manroot tangle. I tapped 100 cones from that cache and collected 11 spiders and a few neobisiid pseudoscorpions. Compared to the lone juvenile spider I'd tapped from the "field" cones just a few yards away, this was a bountiful result.

All eleven spiders were juvenile except for a male and female Ceratinella (Linyphiidae) which didn't immediately match any species Rod was familiar with. Two of the juveniles were Metallina (Tetragnathidae), a genus I'd never found in fallen cones before. In fact, I rarely find anything from the family Tetragnathidae in fallen cones. Rod also collected many juvenile Metallina in his Ferbrache Unit sweep samples.

Read Rod's account here.

A field of peas across the road from the Ferbrache Unit.

No comments:

Post a Comment