Stay or go? Competition affects movement and dispersal in experimental metacommunities

Dispersal and the underlying movement behaviour are processes of pivotal importance for understanding and predicting dynamics of populations and communities which inhabit landscapes consisting of discrete habitat “islands”. Generally, animals decide on whether to stay in their present location or go elsewhere using different sources of information, like the presence of conspecific individuals. However, it remains unclear whether and how dispersal in metacommunities depends on interactions with other species and whether rules derived from single-species contexts can be scaled up to larger communities. To address these issues, we conducted a series of laboratory experiments with three species of protists placed in simple landscapes consisting of two connected “islands”. We observed the frequency of dispersal from one patch to another, filmed movement behaviour of protists under the microscope and used image analysis to describe movement trajectories of protists alone and in the presence of other species. We found that predicting movement and dispersal in metacommunities requires knowledge on behavioural responses to intra- and interspecific interaction strengths. Consequently, metacommunity dynamics cannot be inferred directly from single-species metapopulations without taking interspecific interactions into account. Our work identifies the significance of behavioural adjustments resulting from the presence of competing species for understanding metacommunity dynamics, stability and the coexistence and distribution of species.

Fronhofer E.A., Klecka J., Melián C.J., Altermatt F. (2015) Condition-dependent movement and dispersal in experimental metacommunities. Ecology Letters: Published online: 24 July 2015. DOI: 10.1111/ele.12475