Influence of trophic conditions on biotic interactions under introduction of new species into communities of cladocera

Abstract

We studied the influence of food concentration on success of introduction of alien species into zooplankton communities. Abundance dynamics of the studied species were simulated under different levels of food supply corresponding to oligo- and eutrophic conditions. Computer-simulated experiments indicated that success of the species introduction was affected by equilibrium food concentration. Species with less equilibrium food concentration were more successful. Among the studied species, more competitive ones were Simocephalus vetulus (large-bodied species) and Ceriodaphnia reticulata (small-bodied species). Indeed, Ceriodaphnia reticulata was the most successful under oligotrophic conditions, and Simocephalus vetulus was so under eutrophic conditions. We suggested that large-bodied species could not compete with the small ones under oligotrophic conditions owing to longer life cycle duration and higher energy requirements at the juvenile stage, especially under food insufficiency. The results of experimental and field studies were analyzed to confirm the success of Ceriodaphnia in competition with larger cladocerans under oligotrophic conditions.