Anthropogenic and natural dispersal of Quercus lobata to Santa Cruz Island

We are investigating the role of the Chumash people in establishing populations of Quercus lobata on Santa Cruz Island. Historically, the Chumash used acorns from Q. lobata as a food source. It is therefore possible, that the populations that exist on Santa Cruz may have been purposefully planted for harvest, or passively dispersed. We have extensively documented the phylogeography of Q. lobata estimating population divergence times and responses to previous climate regimes. We intend to sample trees on Santa Cruz Island to compare against this data, and estimate the time of divergence. If the Chumash did disperse this tree to the island, then genetic data will show a more recent divergence time from mainland populations. If, however, trees were established by natural means, we will see a pattern more similar to those already established across the trees range.