Chironomidae assemblages of temporary streams of the Mediterranean island of Majorca (Spain)

The effect of flow permanence and land use as well as the biogeography of the chironomid (Diptera) communities inhabiting temporary streams was studied in the Mediterranean island of Majorca. A total of 52 species were identified from exuviae and pupae, comprising the subfamilies Orthocladiinae (58%), Chironominae (29%) and Tanypodinae (13%). Forty-six species of chironomids were first records for the island of Majorca, seven of which had not been recorded in the Iberian Peninsula before. Most of the genera found have a Holarctic distribution and contrary to what was expected, typical Mediterranean assemblages were not recorded, nor did the chironomid communities inhabiting these streams reflect water temporality. The presence of common species characteristic of permanent running waters where more forms typical of temporary waters were expected, reflect that the streams are only dry for short periods, thus, many species may survive these episodes, either finding refuge as larvae in the damp substrata or by colonising the springs.