Rough and Ready Creek – An evolutionary crossroads

Crossing Rough and Ready Creek on Highway 199 south of Cave Junction, one might be struck by the irony of the little sign proclaiming a botanical wayside in the strangely bleak terrain. Appearing impoverished or burned over, with tortured looking trees, the observer resists the idea that the site is actually a thriving ecosystem. But native plant enthusiasts who have visited the site recognize it as a special place. Once on foot, even a casual observer will be impressed by the rich and intriguing assemblage of wildflowers. Some are rare endemics not found outside the Illinois Valley.

The complementary colors and shapes of flowers and herbage between the rounded cobbles, offer aesthetic treats that diminish only with the departure of spring. Moving down to the water and up the canyon the hiker can extend the experience through the growing season. The broad alluvial bench beside Rough and Ready Creek is one of Oregon’s gems. It is the only significant example of a serpentine ecosystem on the floor of the western interior valley province of Oregon (ONHP 1993).

The biological wealth of the Rough and Ready Creek watershed, a tributary of the Illinois River, is tied to the geologic history of the Klamath Range. This region and the specific subrange, the Siskiyou Mountains, is one of the great reservoirs of biological diversity in North America (Whittaker 1961), In his classic The Klamath Knot, David Rains Wallace aptly calls it “a venerable unity.” The region is a crossroads in time and space where plant species have converged in unique combinations. It is also an important center of endemic species of vascular plants (Smith and Sawyer 1988, Whittaker 1961). Relict species, lost from the adjoining regions, found refuge in the Siskiyous over a period of 40 million years.

Throughout its history, the range provided geographic variation in climate and topography to meet the varied ecological tolerances of species lost elsewhere due to submergence, desiccation, and massive flows of lava or ice. The range has also bridged the evolving floras of the Great Basin and northern California and, for over 10 million years, the emergent Coast Range and Cascade Mountains.

Local speciation contributed a host of narrow endemics, add- ing to the celebrated species’ richness. Many rare plant species of southern Oregon owe their origin to the selective pressures exerted by serpentine soils (Kruckeberg 1969). Massive sheets of ultramafic rock — generally’ referred to as serpentine — are one of the salient features of the range. The red, rocky soils derived from the parent material are high in magnesium and heavy metals, and are calcium-deficient. Some serpentine endemics are only found on the red ultramafic soils, while many regionally common species find the soils intolerable. The structure and composition of the communities offer a distinct and unique ecosystem that stands out abruptly from the non-serpentine matrix (Whittaker 1954).