Table 2 Estimated development temperature sums (D). tmin refers to the date at which the stream water temperature exceeds 4°C for the first time during a given year.
| D(mean ± s.e.) °C | ||||
|---|---|---|---|---|
| Development period | Warm demes | Cold demes | F 1 | P |
| tmin + 2 weeks | 113.3 ± 2.7 | 91.1 ± 3.1 | 22.10 | <0.0001 |
| tmin + 4 weeks | 242.2 ± 4.2 | 220.0 ± 4.5 | 10.64 | 0.0033 |
| tmin + 6 weeks | 394.0 ± 5.1 | 371.1 ± 5.4 | 5.04 | 0.0342 |