Distribution and Habitat Preferences of Icelandic Trichoptera

Abstract

Eleven species of Trichoptera are found in Iceland. Four species occur both in running and stagnant waters, six species prefer very stagnant waters, shallow ponds and swamps and one species occurs mainly in streams. In general each species occupies a much greater range of habitats in Iceland than they do elsewhere in Europe, where the number of species is 20 to 30 times greater. Distributional patterns within Iceland fall into 4 categories: (a) found all over Iceland (5 species). (b) found where summer temperatures are high (4 species), (c) found in the East and North (1 species) and (d) found all over Iceland, except in the East (1 species). Species in the first category are those that occupy the widest range of habitats. In the second category are species that are found only in shallow stagnant waters, which freeze solid during the winter, and all larval growth takes place in the summer. The single species in the third category is a recent immigrant which is profoundly affecting the distribution of the single species in the fourth category.