Jg. Ehrenfeld et Jp. Schneider, RESPONSES OF FORESTED WETLAND VEGETATION TO PERTURBATIONS OF WATER CHEMISTRY AND HYDROLOGY, Wetlands, 13(2), 1993, pp. 122-129
Nineteen mature Atlantic white-cedar swamps, located in four categorie
s of undeveloped and suburban watersheds of the New Jersey Pinelands,
were studied to determine the relationship between perturbations of wa
ter quality and hydrology and changes in species composition and commu
nity structure. Rank-orders of the 19 sites were compared for key vari
ables (ground-water and surface-water NH4 and PO4, mean water-table le
vel and water-table range). Rank orders for the sites were different f
or the various parameters, suggesting little congruence among water qu
ality and hydrologic changes at wetlands within urban basins. Changes
in species composition, measured as the number of invading species, we
re correlated with the number of perturbed chemical and hydrologic par
ameters and were not related to the absolute magnitude of any one para
meter. Sites in developed watersheds supported a larger fraction of fa
cultative upland and upland species than did sites in undisturbed wate
rsheds: this change could affect wetland delineation of urban wetlands
. Urbanization thus increases variability in environmental quality amo
ng sites of a given type of wetland and fosters an increase in proport
ion of non-hydrophytic vegetation within such wetlands.