Genetic differentiation in silicicolous Echinospartum (Leguminosae) indicated by allozyme variability

The genetic identities among several Echinospartum species and the genetic effects of isolation, small population size and decline in the restricted Echinospartum algibicum were studied both at adult and soil seed bank stages. The allozyme data support, to a large extent, population genetic predictions for genetic divergence. The genetic diversity parameters studied demonstrated that the aboveground population of E. algibicum is genetically less diverse than E. ibericum and E. barnadesii. Genetic identity between E. ibericum and E. barnadesii was very high, decreasing to levels considered typical for co-generic taxa between E. ibericum and E. algibicum. With regard to the soil seed bank of E. algibicum, this showed higher genetic variability than the adult population, greater extent of homozygosity, and significantly different allele frequencies at some loci. Despite the small population size, E. algibicum population maintains relatively high levels of genetic diversity both at adult and seed bank stages.