Genetic diversity in peripheral and central populations of the Cantabrian endemism Genista legionensis (Pau) M. Laínz (Fabaceae)

The impact of habitat fragmentation and isolation on the genetic diversity of populations has attracted much attention in studies of plant conservation. The central-peripheral population hypothesis predicts that peripheral populations have reduced genetic variability, so it is often assumed that they deserve higher conservation priority over central populations. In this work, using amplified fragment length polymorphism (AFLP), we studied the genetic diversity of central and peripheral populations of the Cantabrian endemism Genista legionensis (Fabaceae). At the species level, percentage of polymorphic bands, Nei heterozygosity and Shannon information index were PPB = 89.21%, HE = 0.246 and I= 0.377, respectively. The study revealed that peripheral populations were smaller in number, with lower levels of genetic diversity compared to the central populations. Furthermore, analysis of molecular variance (AMOVA) indicated that most of the variability was partitioned among populations, also supported by principal coordinates analysis. This study indicates that the decrease in diversity from central to peripheral populations could be explained as a result of edge effect and fragmentation through the enhanced inbreeding and genetic drift, and thus supported the view that habitat fragmentation and related edge effect reduce the population genetic diversity. However, the presence of discriminating fragments in the peripheral populations suggests their conservation in order to preserve the genetic diversity in the Cantabrian endemism G. legionensis. El impacto de la fragmentación del hábitat y el aislamiento sobre la diversidad genética de las poblaciones, han despertado mucha atención en estudios de conservación de plantas. La hipótesis de la población centro-periferia predice que las poblaciones periféricas reducen la variabilidad genética, por lo que a menudo se asume que merecen una mayor prioridad de conservación respecto a las poblaciones centrales. En este trabajo, hemos empleado los polimorfismos en longitud de fragmentos amplificados (AFLP), para estudiar la diversidad genética de las poblaciones centrales y periféricas del endemismo cantábrico Genista legionensis (Fabaceae). A nivel de especie, el porcentaje de bandas polimórficas, la heterocigosidad de Nei y el índice de Shannon fueron PPB = 89,21%, HE = 0,246 y I = 0,377, respectivamente. El estudio reveló que las poblaciones periféricas fueron menores en número, con niveles más bajos de diversidad gené