TERRESTRIAL BRYOPHYTES AS INDICATORS OF AIR QUALITY IN SOUTHEASTERN OHIO AND ADJACENT WEST VIRGINIA1 MICHAEL B, STEFAN and EMANUEL D. RUDOLPH, Department of Botany, The Ohio State University, Columbus, OH 43210
Abstract. Bryophyte community as well as individual moss species characteristics on soil were examined to determine relationships with proximity to three coal-fired power plants emitting SO2 and a ferroalloy plant emitting chromium among their emission products. Woody vascular plant communities were relatively uniform, whereas bryophyte coverage was halved (from 3.36% to 1.47%) when comparing locations relatively distant from the plants with those closer. Other common community indices varied little with locality. Three moss species which showed the most consistent relationship to distance from the power plants, Dicranum scoparium, Leucobryum albidum, and Polytrichum ohioense, were mapped for presence or absence on 68 similar hillside habitats. D. scoparium and L. albidum consistently were absent in the area most influenced by the emission sources, while P. ohioense was less consistent in its absence. Presence or absence of indicator moss species proved more useful than community characteristics for indicating relative air quality. OHIO J. SCI. 79(5): 204, 1979 Bryophytes, as well as lichens, have been successfully used as indicators of air quality in a number of studies as reviewed by LeBlanc and Rao (1974). Some of these studies imply that increased SO2 concentrations are the major cause of observed reductions in cover values and decreases in the number of species present, although other pollutants such as heavy metals, NOX, HF, and O3 are often present. Most studies examined epiphytic species; however, terricolous bryophytes were used as both indicators of SO2 stress (Winner and Bewley 1978a, b) and airborne heavy metals (Ruhling and Tyler 1971). Previous distributional studies in the area of lichen and bryophyte species on all substrates and habitats were inconclusive. Schutte (1976) reports an elevated Chromium content, 69.5 fxg g"1 dry wt., in the lichens Parmelia caperata and P. rudecta in woods southeast of the Sporn power plant in close proximity to a ferroalloy plant (fig. 1) compared to values of 1.8 at Salt Fork State Park and 12.8 at Hocking State Park, Ohio. Manuscript received 1 June 1978 and in revised form 13 April 1979 (#78-30). 204
Our study was initiated to determine if there were phytosociological and/or species differences among terricolous bryophyte communities of similar habitats at various distances from three coal-fired power plants and a ferralloy plant along the Ohio River. Measurements indicated that at times air in the power plant area is higher in SO2 content than at some distance away (fig. 1). Terricolous bryophytes of this area were used as indicators of air quality as has been reported for other areas. SAMPLING REGION The region studied is underlain by sandstone and shale and consists of rolling topography with a mosaic of cultivated fields, pastures, woodlots, and small towns. Soil associations are Muskingham-Upshur and MuskinghamLatham, both characterized by shallow to moderately deep acid soils on strongly sloping to steep topography (Dotson 1962). Selection of areas for study was determined by the proximity to available mechanical air quality monitoring stations maintained by the power company (fig. 1). During the first year of our study, quantitative community data on vascular and bryophyte vegetation was obtained from 5 sites sampled within 4—11 km of all 3 coal-burning power plants and the ferralloy plant where low level SO2 pollution was measured, and 5 similar sites
Ohio J. Sci.
BRYOPHYTES: INDICATORS OF AIR QUALITY
were sampled at least 24 km from any power plant where the yearly SO2 concentrations were much lower (fig. 1). Only wooded southwest exposures (210°-245°) that had been...