Lichens and Air Quality in Cuyahoga Valley National Recreation Area, Ohio

Abstract

Lichens were collected at numerous localities in Cuyahoga Valley National Recreation Area and compared with species lists for Cuyahoga and Summit counties to document changes in the lichen flora since 1920. There are no historical collections from the park but habitats similar to those studied by early collectors are present in the park today. The present lichen flora has 65 species, including 34 new records for the area. Of the 151 species recorded for the two counties between 1895 and 1917, only 31 were found during this study (21%). None of the species most sensitive to sulfur dioxide were found, nor were any of the cyanophilic lichens reported earlier. The lichens remaining are often small and frequently with dead parts or distorted growth. Elemental analysis of Parmelia rudecta showed high sulfur levels. It is proposed that poor air quality has destroyed 79% of the historical lichen flora of the park. Thelidium parvulum Arn. is reported for the first time from North America. The Cuyahoga Valley National Recreation Area is situated along the Cuyahoga River between Akron and Cleveland in Cuyahoga and Summit counties in northern Ohio. The park was established in 1975 with 32,500 acres (13,200 ha). The park boundaries are artificial and were drawn to exclude most of the developed areas. The river is in a fairly deep valley but the park also includes some of the upland further from the river. In some areas there are sandstone cliffs where streams have cut through the rocks but most of the park is forested. The vegetation is most- ly northern hardwoods with sugar maple (Acer sac- charum), hickory (Carya spp.), oaks (Quercus spp.) and beech (Fagus grandifolia) on the slopes and ridgetops. Most of the american elm (Ulmus amer- icana) are dead. The valleys contain red maple (Acer rubrum), boxelder (Acer negundo), ash (Fraxinus spp.), willow (Salix spp.) and some cottonwood (Populus deltoides). The Ohio and Erie Canal extended the whole