Figure 8.

Estimated trends for representative stream fish and insect species. (a,b) Estimated trends in captures of stream fish (shown by lines) of two species ((a) Ericymba buccata and (b) Noturus miurus) superimposed on the observed counts of these species. Ordinate is logarithmically scaled. Three zero-valued counts (for years 1964, 1966 and 1968) of N. miurus are not shown. (c,d) Trends for insect species: (c) Coleomegilla maculata and (d) Harmonia axiridis. Five zero-valued counts (for years 1989–1993) of H. axiridis are not shown.