A comparison of terrestrial isopod communities among different habitat types on Mt. Chelmos (Peloponnisos, Greece)

Abstract

The mountainous communities of terrestrial isopods (Crustacea, Oniscidea) have not been ex-tensively studied so far, even though they can offer important insights to the structuring of iso-pod diversity, to the role of these animals on mountainous ecosystems and to altitudinal gradi-ents of diversity. In this work we present the results obtained from the Mt. Chelmos lying at the northern part of the Peloponnisos peninsula (southern continental Greece). Eight habitat types exploited by isopods on this mountain, namely highland meadows ('alpine' ecosystems), high-land Astragalus formations, hawthorn formations, fir forest, pine forest, mixed coniferous forest, dense maquis and sparse maquis, were studied using pitfall traps emptied at a monthly basis for seven months. All sampling sites were located at elevation from 800 to 2100 m a.s.l. Species rich-ness recorded in pitfall traps is low (nine species) and is not correlated with elevation. Abun-dance is highest in highland hawthorn formations. Summer months showed the higher abun-dances. One species of the genus Armadillidium (A. tripolitzense) dominates communities of higher elevations, as also found in other Greek mountains. Habitats are clustered according to eleva-tion, forming three groups with similar isopod communities, namely sites above the forest line, fir and mixed coniferous forests, and maquis with pine forest that occur at lower elevations. A comparison with known data for isopods from other Greek mountains is also provided.