Treesearch

Environmental problems are never neatly defined. Instead, each is a tangle of interacting processes whose manifestation and interpretation are warped by the vagaries of time, weather, expectation, and economics. Each problem involves livelihoods, values, and numerous specialized disciplines. Nevertheless, federal agencies in the Pacific Northwest have been given the task of evaluating environmental issues quickly over large areas (USDA and USDI 1994a, REO 1995).

To release a young pine plantation on a medium site in central California, herbicides and mulches were applied soon after planting to study their effectiveness. Bearclover is an aggressive shrub species that resprouts from rhizomes after disturbance, and must be controlled if young conifer seedlings are to become established. After 4 years, resprouting bearclover plants numbered 282,000 per acre in the control, but less than 4,000 per acre in the plots treated by herbicides. Mean foliar cover was 63 percent versus 1 percent for control and herbicide plots, respectively. Ponderosa pine...

Abstract.—I used radio transmitters to determine the diel habitat use and movement patterns of California golden trout Oncorhynchus mykiss aquabonita inside and outside cattle exclosures on the South Fork Kern River, Golden Trout Wilderness, California. Twenty-three golden trout were monitored from September 10 to 19, 1993, during 216 diel-tracking hours at four study sites in upper and lower Ramshaw Meadow. No differences in distances moved or home ranges were detected between golden trout inside and outside exclosures. Mean home ranges were 18.5-54.0 m inside the two exclosure sites and...

Abstract.—I used radio transmitters to determine habitat selection and movement patterns of California golden trout Oncorhynchus mykiss aguabonita in two areas defined by their different levels of habitat recovery in the Golden Trout Wilderness, California. Study areas were differentiated by the amount of streamside vegetation (low or high coverage of beaked sedge Carex rostrata). Lower amounts of streamside vegetation were typically associated with other signs of degradation caused by cattle, including widened streams, collapsed banks, and reduced bank undercutting. Twenty-nine California...

Based on our review of literature and survey of geneticists workingon California taxa, we find genetic information lacking for most speciesin the Sierra Nevada. This situation is likely to remain infuture, with specific groups of taxa or occasional rare or high-interestspecies receiving specific study. Where we do have empirical information,we find few generalities emerging, except occasionally withinclosely related or ecologically similar taxa. Despite these difficultiesin assessing genetic diversity, we direct attention to situations estimatedto be most deserving of attention from a...