The expansion of thermophilic plants in the Iberian Peninsula as a sign of climatic change

Abstract

Investigations conducted in the Iberian Peninsula over the last three decades show how some thermophilic plant species have extended their range. The native thermophilic species, Dittrichia viscosa (L.) W. Greuter, and Sonchus tenerrimus L., have expanded, apparently without any direct intervention by man. In addition, alien species have crossed biogeographical barriers to expand their range into new areas. These include taxa from the neotropics and the Cape Province of South Africa which have colonised areas close to the Mediterranean coast (Ageratina adenophora (Spreng.) King. & H. Rob., Araujia sericifera Brot., Tropaeolum majus L. and Arctotheca calendula (L.) Levyns). By analysing thermometric data series from 10 meteorological stations, we were able to correlate the expansion of the ranges of these species with mean temperature increases, particularly those of mean minimum temperatures. If other thermophilic species (native and introduced) also increase their range, this could have serious consequences for plant biodiversity.