2000 BES Abstracts


Species structure and composition of riparian habitats in the Gwynns Falls riparian corridor.

Wayne C. Zipperer, Grace Brush


In 1999, we initiated a survey of riparian habitat to evaluate how species structure and compositions varied in the Gwynns Falls riparian corridor. Based on urbanization patterns, the watershed was divided into three sections: upper, middle, and lower. Within each section, we randomly located transects within the floodplains of 1st, 2nd, and 3rd streams, and established 100 m2 plots along these transects to inventory the canopy, shrub and seedling/herbaceous strata. We sampled 35 plots in the lower section, 31 in the middle section and 44 in the upper section. Structurally, the lower section differed from the middle and upper sections. The lower section had the smallest mean diameter at breast height (DBH) (9.5 cm), the highest mean stem density (1585 stems/ha), and the lowest mean basal area (20.1 m2/ha). In contrast, the middle and upper sections had a similar means for DBH (11.6 and 10.6 cm), total density (1235 and 1288 stems/ha), and basal area (27.7 and 25.2 m2/ha), respectively. Compositionally, the lower section was dominated by Acer negundo, Fraxinus pennsylvanica, Acer saccharinum, and Morus alba; the middle section was dominated by Fraxinus pennsylvanica, Acer negundo, Liriodendron tulipifera, and Junglas nigra; and the upper section was dominated by Acer rubrum, Lindera benzoin, Platanus occidentalis, and Acer negundo. Species that declined in importance from lower to upper were generally opportunistic-upland species, whereas those species that declined in importance from the upper to lower were riparian species.