Figure 1.

Geographic location and the type of overwintering strategy of the sampled Daphnia populations (abbreviations as in Table 1). Species are differentiated by coloration of the inner circle: D. galeata populations are marked by black letters in yellow circles, D. longispina by white letters in blue circles. The outer ring indicates the overwintering strategy: white for active overwintering under the ice, grey for putative overwintering as dormant eggs only, red for confirmed overwintering as dormant eggs only. The satellite photo of the Tatra Mountain range is based on orthorectified Landsat 7 data (source: U.S. Geological Survey).