Distribution and habitat preferences of some intertidal amphipods in Iceland

Abstract

A total of 801 samples of amphipodsfrom 71 sampling stations on all coasts ofIceland were analysed. Results are presented for eleven species belonging to the families Gammaridae and Talitridae. Three species have a limited distribution around the coasts of Iceland, while the remaining species are found more or less commonly on all coasts where suitable shores exist. The distributional patterns observed were compared to those shown by the same species on the western and eastern coasts of the Atlantic. It is concluded that temperature is an important factor controlling the distribution of these amphipods.

Habitat partitioningwas analysed by use of 41 habitat categories under eleven main headings. Each of the eleven species was found to have a habitat distribution different from that of the otherspecies, with the possible exception of one species pair. Spatially successional series of species could be distinguished along environmental gradients found from sheltered shores with luxuriant fucoid vegetation to exposed shores without fucoids, from high to low tidal levels on rocky seashores, from upper to lower reaches of estuaries and from high-salinity to low-salinity ponds and lagoons. It is probable that habitat partitioning among the speciesresultsfrom differencesin adaptationsto several interacting physical factors, of which salinity, humidity, temperature, and oxygen level can be reasonably identified. Interspecific competition may reduce habitat overlap among species but the data are inconclusive.