Figure 3.

Total %N values in riparian vegetation collected immediately below and above waterfall barriers to salmon at Clatse and Neekas rivers, B.C. R. spectabilis and O. horridus represent nitrogen-rich soil indicator species, T. heterophylla is unclassified, and all others are indicators of nitrogen-poor soil. T-test results: * denotes p < 0.05; ** denotes p < 0.01.