[Picture of <em>Carex cordillerana</em>]

Carex cordillerana ecology and range (October 29, 2008)

Botanist Duncan Thomas disagrees with some of what the Carex Working Group wrote about ecology of Carex cordillerana in our Field Guide to the Sedges of the Pacific Northwest. We wrote, "Its broad, palatable leaves attract grazers, which can easily pull up the shallow-rooted plant. Perhaps it was once more widespread and now persists only on rocky slopes where it receives some protection from livestock."

Thomas has extensive experience with this species in northeast Oregon, from the south side of the Wallowas and from the Imnaha/Horse Creek area, where it is common and grows in steep forested or scrubby draws in dry grassland, often with Carex rossii. He reports that the CWG account gives cattle and other grazers too much credit for C. cordillerana scarcity and inappropriately ignores the role of fire. He has observed that after a fire C. cordillerana can regenerate in the light soil throughout a draw. The plants thrive for a few years but are gradually out-competed by other understory plants including C. geyeri and low shrubs. The population persists longest along the forest/grassland ecotone. He believes that decades of fire suppression may have adversely affected the abundance of C. cordillerana, although it is much more abundant around the Wallowas than records suggest.

Carex Working Group members found C. cordillerana in the North Warners, southeast of Lakeview and about five miles north of the California border. Two subpopulations with a total of over 70 plants were growing in Ponderosa Pine / White Fir forest. The C. cordillerana was growing on steep north-facing slopes where both grazing by cattle and competition from other understory plants were minimized.