GENETIC AND MORPHOLOGICAL VARIATION IN THE LAND WINKLE POMATIAS ELEGANS (MÜLLER) (CAENOGASTROPODA: POMATIASIDAE)

Population genetics and shell morphology have been studied in 11 populations of the poorly colonizing land caenogastropod Pomatias elegans. The total area of suitable habitats in northwest Europe is shrinking and many isolated populations are becoming vulnerable to extinction. In this study we tested whether the concept of management units (i.e. groups of population with significantly different allele frequencies due to demographic independence) is applicable to the conservation of P. elegans. Fst values indicated strong genetic differentiation and thus little genetic exchange between populations. Allozyme differentiation could be explained with an isolation by distance model, whereas morphological differentiation could not. A morphological difference exists between sexes but not sufficient to discriminate males and females. A Mantel test showed no significant relationship between morphological distance (size corrected or not) and genetic distance. Since allele frequencies differed even among populations in areas where P. elegans is not threathened, we conclude that in the case of P. elegans, defining management units with allozymes may not be an appropriate way to select the most suitable populations for conservation.