We used detrended correspondance analysis (DCA) and canonical correspondence analysis (CCA) to relate major patterns in stream-channel and stream-bank plant species composition to a complex watershed-disturbance gradient in the New Jersey Pinelands (Pine Barrens). The watershed-disturbance gradient was characterized by increasing agricultural and developed land cover, pH and specific conductance values, and channel muck. Surface waters in relatively undisturbed basins displayed lower pH and specific conductance values compared with waters in highly developed or farmed drainage basins. Sites within highly altered basins supported a unique group of peripheral and exotic plant species. These indicator species provided a good measure of watershed disturbance. High species variability among relatively undisturbed sites and the persistence of some characteristic Pinelands species at recently disturbed sites precluded the identification of species associated only with undisturbed sites.