Sunday, April 10, 2016

7-Apr-2016 South Fork Manastash Creek, Washington

Site location. Click photos to enlarge.
What with my penchant for sampling in ponderosa pine forests, Snoqualmie Pass being free of snow, and spring having thawed the lower elevations on the east side of the Cascades crest, Rod Crawford and I decided to head over to the Ellensburg area for an early spring sample.  Eastern Washington trips usually require a lot of driving, but I do love it once we're there!

A view from the snow-free south-facing
slope to the still-snowy north-facing side
Rod was concerned that our intended gridspace, which was at about 3,000 feet (950 m) in elevation, might still be blanketed in snow.  That was indeed the case for north-facing slopes in this canyon, but south-facing slopes were snow-free.  This meant we were sampling during the winter-spring transition.  How exciting!  Over the course of the day I sampled three separate cone accumulations. 

Site 1
Site 1
Site 1 cones
We set up shop in an open area between the road and the creek, and I immediately began tapping 50 fallen ponderosa pine (Pinus ponderosa) cones that lay beneath a tree at the base of the south-facing slope.

Xysticus locuples male
I was absolutely astounded by the number and diversity of spiders I tapped from this set of cones: 64 spiders from 9 families and at least 16 genera!  Four species were identifiable, with Xysticus locuples (Thomisidae) by far the dominant one with 23 identifiable specimens. In addition, there were 10 juvenile Xysticus in the sample that couldn't be assigned to species.

Male Xysticus exuvium
I found numerous exuviae in these cones.  The exuviae I was able to collect without crushing were all left behind by penultimate Xysticus males molting into adulthood.

I also sifted two bags of pine needle litter associated with the cones, but collected only 4 spiders and 1 identifiable species, Xysticus montanensis (Thomisidae).  What a contrast to the cones!

Site 2
Site 2
Site 2 cones
I took a second ponderosa cone sample from the creek's floodplain on the snowy side of the canyon.  Most of the snow in this particular spot had melted, but isolated patches remained.  I tapped 50 fallen cones and collected 8 spiders from 5 families and 6 genera.  Two species were identifiable: Lephthyphantes mercedes (Linyphiidae) and Phrurotimpus paralellus (Phrurolithidae).

"Find your calling". Who paints
inspirational messages under remote
creek bridges? Who seeks them there?
At one point while I was sorting a subsample, stinging bites on my legs alerted me to the fact that I had also inadvertently "collected" a swarm of ants in my pants!  I must have stepped on a colony without realizing it.  They seemed to be everywhere all at once, both on and inside my clothing.  I wasted no time in dropping my drawers so I could whisk them away.  Ant swarm removal trumps modesty.

Site 3
Site 3. Note snow behind trees.
Rod pointed out a nice accumulation of fully open Douglas-fir (Pseudotsuga menziesii) cones on the roadside verge just above my floodplain sample, so I tapped 50 of those cones too.  The result: 5 spiders and one species, Zelotes fratris (Gnaphosidae).  We didn't collect Z. fratris in any other microhabitat this day, so for that record alone the sample had been worth taking.

Although taken within sight of each other, the day's three cone samples were remarkably different.  There wasn't even one identifiable species common to any two sites. 

A rare glimpse of the cryptically colored Arachnophile crawfordii!
Beautiful ponderosas!

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