Genetic diversity following demographic recovery in the insular endemic plant Galium catalinense subspecies acrispum

摘要: Galium catalinense (Rubiaceae) is a perennial shrub consisting of two subspecies endemic to California’s Channel Islands: subsp. on Santa Catalina Island, and G. acrispum, state-endangered taxon San Clemente Island. A long history overgrazing by introduced herbivores has contributed population declines in acrispum. We surveyed 12 populations throughout the taxon’s range for genetic variation using eight polymorphic microsatellite loci determine impact this demographic bottleneck. At level, 65 alleles were identified with an average 8.1 per locus, although many rare; effective number locus averaged 2.6. Expected heterozygosity was 0.550. Individual had between six loci, expected heterozygosities ranging from 0.36 0.60, numbers 1.8 3.5 locus. Populations fell into three or four clusters, depending type analysis, which may represent refugia where persisted during intense herbivory. There little evidence bottlenecks substantial inbreeding within populations. These findings, coupled indications recent migration populations, suggest that acrispum currently unlikely be endangered factors, but small sizes make vulnerable future loss diversity. Management strategies based these data, sizes, spatial distribution are discussed.