Segregation of habitat and prey in two sympatric carnivorous plant species, Drosera rotundifolia and Drosera intermedia.

In 1984 a quantitative field study was made on two sympatric species of sundew, Drosera rotundifolia and Drosera intermedia, growing in a small silting-up bog in southern Germany. Both species differ in individual size and abundance but have nearly the same total biomass. Their association along a transect was strongly negative and also the vertical distribution was quite different. D. rotundifolia grows in significantly higher parts of the bog than D. intermedia. The composition of arthropod prey fauna proved to be markedly different in both species. For instance, Collembola were found more frequently on D. rotundifolia, winged insects on D. intermedia. The reasons for these differences are probably different microhabitats and different shapes of the plants. Seasonal dynamics of the arthropod populations affect their share in the composition of prey.