Open AccessDo the island biogeography predictions of MacArthur and W ilson hold when examining genetic diversity on the near mainland C alifornia C hannel I slands? Examples from endemic A cmispon ( F abaceae)
Author(s) -
McGlaughlin Mitchell E.,
Wallace Lisa E.,
Wheeler Gregory L.,
Bresowar Gerald,
Riley Lynn,
Britten Nicholas R.,
Helenurm Kaius
Publication year - 2014
Publication title -
botanical journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.872
H-Index - 68
eISSN - 1095-8339
pISSN - 0024-4074
DOI - 10.1111/boj.12122
Subject(s) - insular biogeography , mainland , biogeography , genetic diversity , biology , ecology , isolation by distance , taxon , mainland china , geography , genetic structure , genetic variation , population , genetics , archaeology , demography , gene , sociology , china
The C alifornia C hannel I slands are a group of eight oceanic islands located off the coast of southern C alifornia that are substantially closer to the mainland than most other well‐studied island systems. The equilibrium theory of island biogeography proposed by MacArthur and W ilson posits that species diversity on an island will be positively impacted by island area and negatively impacted by isolation, which has been confirmed for the C hannel I slands. In this study, we have extended MacArthur and W ilson's theory to examine how levels of genetic diversity relate to four island characteristics (island area, distance to the mainland, distance to the nearest island, plant diversity) in the endemic perennial taxa of A cmispon ( F abaceae) on the C hannel I slands. We sampled two island species of A cmispon , A . argophyllus and A . dendroideus , from all islands, and mainland sister taxa for nuclear microsatellites, low‐copy nuclear sequence and plastid sequence data. We found that only one measure of diversity from one genetic region (low‐copy nuclear) was correlated with island area, that there was no support for a relationship between genetic diversity and distance to the mainland and that distance to the nearest island was a predictor of low‐copy nuclear genetic diversity. Plant diversity was a significant predictor of plastid genetic diversity when considering all samples. We conclude that the equilibrium theory of island biogeography does not hold for measures of genetic diversity in the C hannel I sland endemic A cmispon based on island area and distance to the mainland. The short distance between individual islands and the mainland probably facilitates a moderate rate of mainland to island dispersal, preventing the islands from functioning as isolated biogeographic units. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society , 2014, 174 , 289–304.