Table 1. Physico-chemical properties of the study sites.

Stream	pH		Specificconductance		Dissolvedoxygen		Depth		Current atsurface		Current atsubstratum
			(µS cm−1)		(mg L−1)		(cm)		(m s−1)		(m s−1)
M	7.6b	±0.2	793b	±57	5.2b	±3.3	55b	±16	0.20b	±0.11	0.12b	±0.10
W	7.7c	±0.2	762c	±61	6.1a	±3.4	38c	±15	0.28ad	±0.25	0.19ac	±0.18
G	7.8a	±0.2	608a	±22	6.0a	±1.7	28a	±24	0.31a	±0.20	0.19ac	±0.14
O	6.4d	±0.2	141d	±30	5.8a	±2.0	41c	±12	0.27cd	±0.17	0.21c	±0.16
P	7.1e	±0.1	255e	±17	4.5c	±2.3	27a	±16	0.24c	±0.15	0.17ad	±0.16
R	7.4f	±0.1	327f	±113	3.8d	±2.6	39c	±14	0.25cd	±0.15	0.15bd	±0.13

Means and standard deviations of measured parameters to characterize streams Moosach (M), Wiesent (W), Guenz (G), Grosse Ohe (O), Perlenbach (P) and Suedliche Regnitz (R). Mean values followed by the same letter within a column are not significantly different. The parameters indicated as current represent the current speed measured either 5 cm below the water surface (“current at surface”) or 5 cm above substratum (“current at substratum”).