57 
Crossosoma 34(2), Fall-Winter 2008 
THE LICHENS ON SAN MIGUEL ISLAND, 
CHANNEL ISLANDS NATIONAL PARK, CALIFORNIA: 
A PRELIMINARY CHECKLIST. 
Kerry Kimdsen 
The Herbarium, Department of Botany & Plant Sciences, 
University of California, 
Riverside, CA 9252 1-01 24. _ 
kk999@msn.com 
ABSTRACT: 141 lichens are reported from San Miguel Island, Channel Islands 
National Park, Santa Barbara County, California. 
KEYWORDS: Biological crusts, caliche, calcareous lichens, Dudleya , grazing, 
terricolous lichens. 
INTRODUCTION 
San Miguel Island in Channel Islands National Park is the most northern and 
westerly of the Channel Islands. It is about 10 km (6 miles) long with a total area 
of 34 km (14 square miles). The island is a plateau with two rounded hills, Green 
Mountain and San Miguel Hill, rising to 244 m (800 feet) in the center. Dense 
fog and strong winds are frequent. The average temperature is a cool 14° C (59° 
F) though rarely temperatures can reach 32° C (90° F) (Schoenherr et al. 1999). 
San Miguel was heavily impacted by sheep ranching, which started in the 1850s, 
though the island has had over forty years to recover since the last animals were 
exterminated in 1966 (Roberts 1991). San Miguel probably once supported island 
chaparral, maybe even Quercus pacifica based on the lichens found there, but the 
dominant shrub is Baccharis pilularis now. There are large areas of grassland and 
dunes. Caliche is plentiful, supporting many calcareous lichens, and there are 
deposits of volcanic rock and dacite on the island (Weigand 1998). Harris Point, 
Lester Point, and lower Willow Canyon support diverse communities of maritime 
lichens. 
My survey of the lichens lasted seven days in June, 2006, and concentrated mainly 
on sites from Green Mountain to Caldwell Point and lower Willow Canyon. I did 
not attempt to cover the whole island. The surveys were qualitative and intuitive 
and concentrated on species diversity rather than distribution. Collections by 
the author are deposited in the University of California Riverside Herbarium 
(UCR). More detailed information is available online (http://sanders5.ucr.edu/ 
lichensflatindex.php). I spent three days at the Arizona State University Lichen 
Herbarium (ASU) examining San Miguel Island collections made by Janet Marsh 
