Setting conservation priorities: The case study of Carabus solieri (Col. Carabidae)

Abstract

C. solieri is an endangered species of Carabidae which is mostly associated with humid forests of the Alps, in France and in Liguria (Italy). We reanalysed morphological data published by Bonadona and compared the results to the molecular data set presented here. We used partial sequences of the mitochondrial cytochrome b gene and seven microsatellite loci to evaluate genetic diversity among and between populations and to propose a phylogeographic scenario. We recognised two basic entities, considered as subspecies, which probably colonised the present distribution range from two main refugia (in France and in Italy). There is no strict agreement between morphological and molecular data and we propose that hybridisation and introgression between the two subspecies have led to the observed patterns of distribution of the characters. Our results show that sampled populations differ significantly in microsatellite allele frequencies even though some populations are < 15 km apart. Gene flow estimates between the 19 sampled populations indicated very restricted exchange. This is in agreement with the low vagility observed for most species of Carabus. Consequently, the Solier's Carab is genetically structured on an extremely fine scale, and local population within a definite forest should be considered as management units. In the light of our data on C. solieri we discuss the usefulness, when hybridisation occurs, of the two main criteria usually quoted for identifying candidate populations for conservation management (uniqueness and diversity) and give some conservation recommendations for C. solieri.