Thursday 20 May 2010

Sagebrush Steppe - brown wave among clouds of blues

We ventured east of the Cascade mountains again on Sunday to Umtanum Creek, Kittitas county. This area is technically rain shadow desert environment and now is a good time to visit - before it gets too hot and the vegetation is not yet parched. It was still pretty hot on Sunday. Photographed hundreds of plants, many in flower, saw my first Western Bluebird. Many rattlesnakes. Just the one moth.


View Larger Map


Sagebrush steppe or desert habitat in the valley of the Umtanum Creek, west of Yakima Canyon. Prairie Lupins and Balsamroot (the yellow flower) are in bloom.

The Umtanum Creek (left) is mosaiked with sagebrush steppe & rocky grassland around the lower talus slopes of the valley, woody riparian scrub and groves of aspen and cottonwood trees on its floor.
In spite of the abundance of unseen before wildlife was pleased to find a moth on this trip. Clouds of blues (I think these are mostly Boisduval's Blue Plebejus icarioides) were congregating around the creek (rushing, presumably from high altitude snow-melt) and sipping moisture from the small patches of damp silt at its margins (left, the photo also shows some rather bedraggled Equisetum arvense but Equisetum laevigatum was also present - this is the smooth stalked scouring rush - which seems a somewhat oxymoronic name). The mesic zone in this landscape is very narrow and walking along the creek feels like visiting a ribbon oasis in a wilderness of dry basalt rock and sagebrush. We also saw a number of Checkerspots and a yellowish bird-size butterfly which I couldn't get close enough to photograph or identify. The small moth, which was also sipping water from the silt, is the Dark-ribboned Wave (Leptostales rubromarginaria) - the only western member of a Geometrid genus - endemic to the new world - of about 55 species.

No comments:

Post a Comment