Population genetic structure in the endemic Begonia of the Socotra archipelago

Begonia socotrana is endemic to the island of Socotra in the Arabian Sea. Its total range is < 15 x 10 km. Genetic surveys using 5 microsatellite loci were undertaken to investigate patterns of reproduction and dispersal to provide baseline data for conservation programmes. The species is not patimictic (theta=0.096, P<0.01) and there is evidence for isolation-by-distance. Despite the plants producing bulbils and being self-fertile, the genetic data is consistent with outcrossing sexual reproduction. Begonia samhaensis is endemic to the neighbouring island of Samha. Its total range is < 150 x 50 m. Two B. socotrana microsatellite primers amplified products in B. samhaensis, but detected no variation. The conservation status of these species has been evaluated and we recommend that B. socotrana be used as a Flagship Species to highlight conservation issues on Socotra. The limited population size of B. samhaensis makes it vulnerable to extinction, and in need of active conservation. (C) 2003 Elsevier Science Ltd. All rights reserved.