Types of response to environmental changes in cladoceran populations

Abstract Cladocerans are a usual component of lacustrine plankton, even though they are often characterized by low species numbers and high structural monotony. In most cases, population dynamics of cladoceran communities seems to be influenced by biotic interactions rather than by chemical and physical variations in the environment, if these occur in a nontraumatic way, because of the central role cladocerans play in the lacustrine food‐chain and the relatively uniform tolerance displayed by different taxonomical entities towards the abiotic components of the system. In this paper we shall consider three situations that can be regarded as paradigmatic to illustrate different responses of cladoceran populations: the case of a great lake where environmental changes have occurred gradually over a long period of time (Lago Maggiore), that of a lake traumatically exposed to a massive toxic input and now in a phase of recovery (Lago d'Orta), and lastly that of a shallow lake subject to sudden, severe changes i...