Indirect effects of forest management on riparian zone characteristics in the Adirondack uplands of New York

Riparian zones are transitional areas between streams and adjacent terrestrial habitats, and they typically have vegetation communities distinct from both. To identify possible effects of forest management within a watershed on riparian plant community structure and riparian zone width, understory vegetation was sampled in three managed and three unmanaged (Forest Preserve) watersheds (250-550 ha) in the Adirondack Park, New York, at three lateral distances (2, 7, and 12 m),from the stream (n = 6). Abundance of herbs was greater at Preserve sites, although richness was not affected by land use. Abundance and richness both decreased with distance from the stream within each land use type, and this decrease was less steep at Forest Preserve sites. Abundance of saplings was greater under management, and saplings did not respond to distance from the channel. Binary discriminant analysis demonstrated differences in herb community composition between land uses, although this difference decreased with increasing proximity to the channel. Although none of the riparian areas in this study have been directly logged, this study shows that indirect effects of management in a watershed (e.g., increased light and evapotranspiration) can alter the riparian herbaceous community, increase the density of saplings, and narrow the riparian zone of small upland streams.