California Institute for Energy and Environment (CIEE)

This project studied whether transmission lines are contributing to the decline of endangered species in the Lokern area of Kern County, California. We compared the demography of the endangered plant Kern mallow (Eremalche kernensis) in transmission line/road corridors and control (undisturbed) areas, quantified the abundance of nonnative plants relative to distance from roads, and collected data regarding Kern mallow population stability. Kern mallow survival was significantly lower in corridors than in controls, but flower production and seed-to-ovule ratios were not. Kern mallow abundance was not correlated with distance from roads. Survival and reproductive rates of Kern mallow were lower in burned areas, and Kern mallow plants in burned areas were less tolerant of disturbance from corridors or livestock grazing than those in unburned areas. Soil type, burn history, and grazing history seem to have a greater influence on plant species composition in the Lokern area than do corridors. The relative cover of nonnative species did not differ between corridors and controls and was not correlated with distance from roads. Our preliminary conclusion is that road corridors, with or without transmission lines, are reducing the overall survival rate of Kern mallow but are not affecting the dominance of nonnative plants in the Lokern area. Restricting access to existing roads is not necessary, but creation of new access roads should be avoided. Better management of livestock and wildfires is recommended. Kern mallow population trends cannot be predicted until additional data are collected