Temporary Water Crustaceans: Biodiversity and Habitat Loss

Abstract

Temporary waters are those that exhibit recurrent dry phases that, for specific waterbodies, are oftentimes predictable both in their time of onset and their duration. They include coastal marine, inland saline, and freshwater bodies, but this discussion focuses on the latter two types. Physicochemical features strongly influence the faunas present, but biological factors may be important also especially with increased duration of the aquatic phase. Insects and crustaceans dominate the fauna and comparisons between these two groups are made. The latter are well represented by micro- and macro-forms from the following major taxonomic groups: Branchiopoda, Ostracoda, Copepoda, Decapoda, Peracarida, and many rare species are present. Highest species richness appears to be associated with a hydroperiod of between 150-250 days per year. Crustacean biodiversity may be extremely high in some regions; for example, over 90 species of branchiopods and copepods have been recorded in wetland ponds on the coastal plain of Atlantic North America. This diversity is under threat from a variety of human activities, especially agriculture and land development, and also is likely to be affected by global climate change. Case histories are examined, as are management practices that may negatively impact crustacean biodiversity. Maximum diversity is likely to be best achieved by ensuring a range of natural drought regimes in temporary waters across wide geographical, physiographical, and climate conditions.