Fig. 3
Relationships between mean water temperature (T in °C) in the preceding winter (as open points in Fig. 1a) and a actual numbers N of species (among a list of 50 easily recognizable macrozoobenthic species) found in late-winter/early-spring in (solid points) all samples together (15 sites × 0.95 m2) and (open points) mean number per sampling site (0.95 m2). In b, these numbers of species have been de-trended for the influence of year number (see text). The numbers found in 1991 are indicated separately by crosses (plus for 14.25 and multi for 0.95 m2, respectively). Best linear fits: (a, full line, solid squares) N = 25.1 + 1.70 T (r = 0.67, n = 39, P < 0.0001), (a, dashed line, open circles) N = 11.0 + 1.00 T (r = 0.72, n = 39, P < 0.0001), (b, full line, solid squares) N = 27.9 + 1.11 T (r = 0.57, n = 38, P < 0.002), (b, dashed line, open circles) N = 12.7 + 0.63 T (r = 0.71, n = 38, P < 0.0001)