The immigrant triclad flatwormDugesia tigrina (Girard) (Plathelminthes, Turbellaria). Range-extension and ecological position in The Netherlands
- Cite this article as:
- Van Der Velde, G. Hydrobiological Bulletin (1975) 9: 123. doi:10.1007/BF02263331
The possible routes which could have been followed byD. tigrina in the course of its immigration in the Netherlands are discussed (Fig. 1). The species is almost restricted to the larger, eutrophic waters and is found usually under stones. The absence of species in smaller waters, such as ditches, could be explained by an interaction of various factors. The succesful immigration ofD. tigrina in the larger waters is partly due to the very catholic and opportunistic manner of feeding, by which the species can co-exist withD. polychroa. The distribution pattern and habitat ofD. tigrina in the Netherlands is similar to that ofPlanaria torva (this species is, however, more widely distributed in the Netherlands). The two species probably have solved the problem of co-existing withD. polychroa in a different way. The thermal pollution of today is favourable for a thermophilous species, such asD. tigrina.