The Entomostracan and Rotifer Communities Associated with Submerged Plants in the Norfolk Broadland — Effects of Plant Biomass and Species Composition

Abstract
The microcrustacean and rotifer communities associated with submerged aquatic plants were studied over a three‐year period in a series of experimental ponds, created within a fenland drainage ditch. Seasonal abundance and spatial distributions were assessed. The ponds contained a varying amount of vegetation, dominated either by Ceratophyllum demersum or Stratiotes aloides and this had consequences for the ponds' animal communities. Increasing densities of Ceratophyllum were associated with increases in weed‐associated entomostracans whereas increases in Stratiotes led to a general decrease in associated animals. Increases in both plant species led to reductions in abundance of Daphnia, but to differing amounts. A relatively low density plant population in the presence of zooplanktovorous fish did not provide a refuge from predation for large‐bodied Cladocera.