|The distribution of Asellus aquaticus and A. meridianus (Crustacea, Isopoda) in Britain|
|Williams, W.D. (1979). The distribution of Asellus aquaticus and A. meridianus (Crustacea, Isopoda) in Britain. Freshwat. Biol. 9(5): 491-501. dx.doi.org/10.1111/j.1365-2427.1979.tb01533.x|
|In: Freshwater biology. Blackwel Scientific Publications/Blackwell Scientific Publications: Oxford. ISSN 0046-5070, more|
Asellus aquaticus and A. meridianus are freshwater isopods common more or less throughout Britain. It has been suggested that the former species is replacing the latter. To investigate this, the distributions of the species were determined in the English Lake District, near Merseyside, and elsewhere. Additionally, some field transference experiments were conducted in Anglesey and near Merseyside. Particular attention was given to changes in distribution with time; many of the observations reported relate to a time span of almost 20 years. Taken together, the results provide qualified support for the suggestion that A. aquaticus is replacing A. meridianus.