Littoral microcrustaceans (Cladocera, Copepoda) in a prairie coastal wetland : seasonal abundance and community structure

Abstract

Seasonal species abundance and community structure of the littoralmicrocrustacean community (Cladocera, Copepoda) in two areas of DeltaMarsh were investigated over the open-water season. Cladoceranabundance in Crescent Pond, with no fish, only invertebrate predatorswas considerably higher than in Blind Channel, with both fish andinvertebrate predators, and where cyclopoid copepods were thedominant microcrustaceans. In both areas, a small number of speciesof planktonic cladocerans characterized the community in spring andearly summer, whereas a diverse array of species of phytophilouscladocerans comprised the community throughout the summer. Daphnia rosea was the most abundant species in the planktoniccommunity in Crescent Pond for the first half of the summer, and Ceriodaphnia dubia was most abundant in the last half. In contrast,no single planktonic cladoceran species was consistently mostabundant in Blind Channel. The sequence of dominant phytophilouscladoceran species observed in Crescent Pond through the season wasChydorus sp. 2, Simocephalus vetulus, Pleuroxusdenticulatus, and Ceriodaphnia dubia, and in Blind Channel,Alona circumfimbriata, Simocephalus vetulus, and Ceriodaphnia dubia. Dominant planktonic and phytophilous copepods inboth areas were Diacyclops thomasi, Acanthocyclops vernalis,Eucyclops agilis, and Macrocyclops albidus. Canonicalcorrespondence analysis revealed differences in community structurebetween areas of the marsh related to turbidity, phytoplanktonbiomass, and soluble reactive phosphorus concentration.