Bryophytes in old-growth forests of western Massachusetts

Old-growth forests constitute rare habitat that may support rare bryophytes (mosses and liverworts) or provide refugia for populations once more widely distributed. This study was undertaken to determine what differences, if any, can be found between the bryophyte flora of old-growth and nearby second-growth forest sites matched for elevation, slope, aspect, and forest type. Bryophytes were censused on trees, logs, rocks and exposed soil in four western Massachusetts old-growth stands and in four second-growth stands. Ninety-one bryophyte species were identified; the majority of species were sparsely distributed. Several species either occurred only in old-growth or were most abundant in old-growth, although no species was strictly associated with old-growth. The total number of species on trees in old-growth is nearly twice that of species on trees in second-growth, and Acer saccharum in old-growth hosted more bryophyte species than Acer saccharum of same diameter in second-growth. Abundances of substrate available for bryophyte colonization were similar in old-growth and second-growth. Although old-growth and second-growth plots had similar bryophyte floras, there may be important differences in habitat provided by these forest types, and some less common species may be slow to recolonize cleared areas.