EFFECTS OF ACIDIFICATION ON BRYOPHYTE COMMUNITIES IN WEST-VIRGINIA MOUNTAIN STREAMS

Bryophytes (mosses and liverworts) are often more responsive to water chemistry changes than are vascular plants. In this study, the relatio nships of bryophyte communities to stream pH and water chemistry were studied, using six streams on or near the Fernow Experimental Forest i n Tucker County, West Virginia. Streams were surveyed with line transe cts using stratified random sampling. Bryophyte communities, based on species composition and structure, fell into three groups, correspondi ng to basic, moderately acidic, and very acidic stream water. For stre ams with sandstone beds, species diversity declined with decreasing pH , and no bryophytes were present at pH 3.15. The dominant species in m oderately acidic to highly acidic streams is Scapania undulata, a spec ies found to have exceptional tolerance to high acidity and toxic meta l levels in Europe and Japan. Scapania undulata was transplanted from a stream with a pH of 5.97 to one with a pH of 3.15. In 3 mo, ultrastr uctural damage was observed. Acidity (pH) probably was not the only fa ctor involved in controlling species composition and cell ultrastructu re, since the two most acidic streams are subject to acid mine drainag e and have very high concentrations of dissolved solids, particularly SO4 and Al. Other trace metals commonly associated with acidic surface waters also may have contributed to the differences in species compos ition.