Distribution patterns of Iberian Carabidae (Insecta, Coleoptera)

Abstract

We have categorised the 1336 species and subspecies of the Iberian Peninsula according to the chorotype classification proposed by Vigna Taglianti et al. (1992), modified by the addition of new chorotypes. The Iberian Peninsula is noticeable among the different European and Circum-Mediterranean regions by the high proportion of endemic taxa (43.1%). The old age and stability of the northern half, the extreme position of the Peninsula within the Eurasiatic continent, alpine tectonics and abundance of caves are among the factors that have probably contributed to the origin of a distinctive fauna. Taxa with a large distribution pattern are predominant at a regional scale; the proportion of endemic taxa increases to the North and in mountain regions; Mediterranean elements are more frequent in the South whereas European elements increase in the northern half. Adaptation to a Mediterranean climatic regime and dispersal are two of the factors causing these patterns. The Peninsula is poor in Afrotropical elements, probably because of the strong isolation derived from the Sahara Desert. The Balearic Islands have high proportions of widely distributed and Mediterranean taxa, what suggests a main role of dispersal in the colonisation of the archipelago. The proportion of endemic taxa in Mallorca (7.8%) is intermediate between that of Sardinia and Sicily; in spite of a relatively long isolation, the Balearic Islands are small in size and moderately rich in caves, what explains that most endemic taxa are found in the lowlands.