Lichen Communities on Conifers in Southern California Mountains: An Ecological Survey Relative to Oxidant Air Pollution

Abstract

In comparison with collections from the early 1900's when oxidant air pollution was essentially absent, 50% fewer lichen species were found on conifers during 3 yr (1976—1979) of collecting and sampling in the mountains of Southern California. Among the five mountains ranges studies, the San Bernardino Mountains, the region with the highest oxidant levels, had lower lichen frequency and cover values. Within the San Bernardino Study sites, lichen cover was inversely related to estimated oxidant doses. Furthermore, at sites with high oxidant levels, marked morphological deterioration of the common species Hypogymnia enteromorpha was documented. Transplants of this species from the relatively unpolluted Cuyamaca Rancho State Park into the San Bernardino Mountains exhibited similar deterioration after a year's exposure.