Variation in patterns of composition and abundance of cladocerans in littoral and open water habitats of Loch Coire Fionnaraich, Scotland

Variation in composition and abundance of Cladocera in littoral and planktonic habitats was studied in a small, remote, oligotrophic Scottish mountain loch, Loch Coire Fionnaraich (LCFR) between Spring 2001 and Summer 2002. Four micro-habitat types, macrophytes, sand, boulders and plankton were selected for sampling. At least three vertical replicate samples were taken for planktonic Cladocera on each of the sampling occasions. For the littoral Cladocera, at least two horizontal replicate samples were taken from each habitat type. Cladocera data were expressed as percentage composition. Most commonly found cladocerans occupying littoral and open water habitats of LCFR were assessed with their autoecological characteristics. The variation in patterns of cladoceran community in planktonic and littoral habitats was assessed by TWINSPAN classification. In TWINSPAN Bosmina coregoni, a planktonic Cladocera, was the best indicator species distinguishing the planktonic and littoral habitats. Polyphemus pediculus, a dominant littoral specialist, separated summer samples from those collected in other seasons. Monospilus dispar distinguished the sandy habitat from other littoral micro-habitat types. Our results indicate that cladocerans are explicitly utilising the planktonic and littoral habitats of LCFR and the sedimentary remains of Cladoceran assemblages have potential in studying palaeoenvironmental change.