Ecological Notes from Cowiche Canyon

Cowiche Canyon Recreation Area is located on US12 just west of Yakima, Washington. The region receives 9-14 inches of rain per year, making it a dry area; thus, the trail system includes both shrub steppe (uplands) and riparian (along Cowiche Creek) habitats. We followed the main trail along the path of a rail line that was in use between 1913 and 1984 along the creek; however, the wetland is very narrow, in places constricted to less than 100 yards. Thus, I encountered plants from both environments.

The canyon walls are composed of a series of basalt ledges with intervening slopes covered by talus and colluvium, which are part of the shrub-steppe habitat. I discussed the geology of the area in another post.

The recreation area is maintained by the Cowiche Canyon Conservancy in partnership with Bureau of Land Management. This stone is a piece of the columnar basalt that lines the canyon.

It’s fortunate that I visited this area during spring, which lasts a little longer here in the Pacific Northwest. As always, I used CoPilot (AKA ChatGPT) for identification while I try to remember scraps of the huge amount of information presented in this mixed environment.

This is Asclepias speciosa, also known as showy milkweed. It is native to Yakima county and is a host species for Monarch butterflies.

The leafy shrub with dark leaves is snowberry–Symphoricarpos albus (or possibly S. oreophilus, which also occurs around Yakima).

The low, brightly colored shrub with straight stalks is probably wax currant (Ribes cereum). The bright green is small leaves and the small patches of pink–barely visible in the photo–are the flowers. These are both native plants.

CoPilot wasn’t so sure about this, but it might be Creek or Red-osier Dogwood (Cornus sericea). This specimen was growing in the bottom of the canyon, not far from Cowiche Creek, which is a natural location for this native riparian species. It will probably become a small tree.

This is my favorite from the walk. Silky lupine (Lupinus sericeus) is one of the signature wildflowers of eastern Washington. I sure am glad we caught them in bloom.

This looks like Pale‑stem buckwheat (Eriogonum heracleoides), another native wildflower to the shrub-steppe habitat.

My untrained eye thought this was Pale-stem buckwheat, but CoPilot pointed out the different leaf pattern and color. This is (probably) Sulphur Buckwheat (Eriogonum umbellatum), another common wildflower to Yakima County’s uplands.

Antelope bitterbrush (Purshia tridentata) is a foundation species of the steppe. This young one had lots of flowers, but the old ones have bare branches; and groups of them grow and die together in cohorts after a disturbance like a wildfire. Yet another native plant.

After some discussion, and sharing a close-up, CoPilot swears (hahaha) this is Woods’ rose (Rosa woodsii). However, its justification fits what I see with my own, somewhat confused eyes.

Here’s a close-up of the fruit. The shrub is covered with small nuts that have a distinctive shape, and are definitive for a wild rose. This is another native species to the steppe habitat of Eastern Washington.

This photo, looking across Cowiche Creek, puts it all together for me. On the other side of the canyon we see columnar jointed basalt, several plant species similar to snowberry, bitterbrush, and buckwheat. Along the creek are dogwood and wild rose; and in the foreground is (maybe) big sagebrush (Artemisia tridentata).

When I took this picture, all I saw was a bunch of plants. After carefully examining them with CoPilot, it has become a mixed riparian-shrub-steppe habitat. However, I didn’t see/hear any birds or other animals, even though it was a cool day with temperatures in the mid-sixties.

CoPilot was a great help, but it is not infallible–more like working with someone who has studied some biology/ecology. After all, it is only a Large Language Model, not an AI system trained on recognizing plant species. Nevertheless, it was a great collaborator and I learned a lot from our collaboration.