How much is enough? Minimum sampling intensity required to capture extant genetic diversity in ex situ seed collections: examples from the endangered plant Sibara filifolia (Brassicaceae)

摘要: Sibara filifolia (Brassicaceae), Santa Cruz Island Rock Cress, an endangered annual plant endemic to the California Channel Islands which was presumed extinct for nearly 50 years, is currently known from only a few small patches on San Clemente (SCl) and Catalina (SCa). In addition protecting extant populations, recovery efforts have included ex situ seed collections hedge against stochastic population losses. We examined genetic diversity structure in wild effect of sampling intensity using 13 species-specific microsatellite loci. Much variation each island consisted rare alleles; 33 % or 56 % (SCa) non-fixed alleles occurred at frequencies ≤0.05. Patches SCl were genetically depauperate (mean HO = 0.002) compared SCa HO = 0.344). One patch distinct, while remaining four indistinguishable. The three distinct those SCl, but not one another. Simulated found that 10 individuals sufficient capture 90 % normalized measures (NE, HO, HE) population, 30 necessary diverse population. However, 125 60 all present. These findings indicate theoretical guidelines recommend targeting 50 per overestimate effort required adequately preserve common alleles, may underestimate most populations.