Acari of the British supralittoral

The acarine faunas of supralittoral tidal debris and lichens were examined on a number of shores; differences in the faunas were attributed to different environmental factors within the two habitats. The Acari may be divided into three ecologically defined groups: (a) maritime species which are confined to the seashore, especially the supralittoral, but may venture into the upper littoral zone; (b) non-maritime species which frequent the seashore, but usually occur inland in soils, leaf litter, and/or vegetation; and (c) nomadic species which migrate freely and regularly between the littoral and supralittoral zones. On the Isles of Scilly some maritime species are absent, and are replaced by non-maritime forms. Freeliving Acari are generally preadapted to the supralittoral zone, and no specializations have been noted among the fauna.