A comparison of the composition of permanent and random vegetation plots in the Gwynns Falls watershed
Erika Monee’ Mc Afee and Dr. Joel Snodgrass
Eight permanent plots were established in 1998 in the Gwynns Falls watershed for the purpose of monitoring vegetation over the long term. Locations of these plots, four near the upper watershed and four in the middle watershed, were selected to represent the Gwynns Falls vegetation. In addition to the permanent lots, vegetation has been sampled in plots located randomly throughout the watershed. A comparison of measurements made in the permanent and random plots this past summer provides information about the degree to which the permanent plots are representative of the vegetation in the watershed.
The results of the study show that while the majority of the species in the middle watershed permanent plots are the same as the random plots, the upper watershed plots show some differences. Overall, there is more overlap of tree species than of ground cover species (herbs and small shrubs and saplings), especially in the upper watershed. The random plots, especially in the upper watershed, contain a greater diversity of tree and shrub species. Species that occur in the random plots but not in the permanent plots include Carpinus caroliniana, Robinia pseudo-acacia, Rosa multiflora, Tovara virginiana, Oxalis europaea, Geum lanciniatum, Impatiens canadensis, Pilea pumila and Vinca spp. Species that occur in the permanent plots but not in the random plots include Carya spp., Chionanthus virginiana, Amelanchier canadensis, Desmodium nudiflorum, Vaccinium corymbosum and Rosa spp.