Coherence and horizontal movements of pathces of Holopedium gibberum (Cladocera)

Abstract

The horizontal spatial dynamics of Holopedium gibberum in a small lake was followed during two summers. H. gibberum individuals aggregated into a single patch measured in tens of meters. Patch movement was extensive throughout the limnetic region, bore no apparent relationship to wind action, and patch structure remained cohesive regardless of weather conditions. Grazing activity by H. gibberum within the patch was intensive, reducing phytoplankton density to half that outside the patch. © 1983 Springer-Verlag.