Biological recovery from lake acidification: Zooplankton communities as a model of patterns and processes

Knowledge of the recovery of aquatic communities from lake acidification is limited. Data from studies of crustacean zooplankton communities, however, do reveal some of the major mechanisms important in the biological recovery process. Important influences on recovery include factors related to habitat quality and the ability of organisms to colonize. During recovery, existing species and colonists from internal and external sources interact to form a new community. The relative roles of internal and external influences remain poorly understood. Four general community types can be identified as possible outcomes of the recovery process: the original community, a normal alternate community, a community limited by dispersal, and a community limited by biological resistance. Empirical data indicate that, given suitable water quality, about a decade is sufficient to permit substantial recovery of zooplankton communities if there are no severe physical or biological barriers to restructuring.