Crop genetic diversity metas

An interesting Letter to Nature entitled “Effects of biodiversity on the functioning of trophic groups and ecosystem” here. A meta-analysis of studies that have “experimentally manipulated species diversity … shows that the average effect of decreasing species richness is to decrease the abundance or biomass of the focal trophic group, leading to less complete depletion of resources used by that group … (but also that) … the standing stock of, and resource depletion by, the most species-rich polyculture tends to be no different from that of the single most productive species used in an experiment.” Are there enough data out there for a similar meta-analysis of experimental manipulations of genetic diversity in crop fields?

Frozen olives

A paper in the Journal of Biogeography reports on the biggest ever microsatellite study of wild and cultivated olives in the Mediterranean. There is a cline in diversity from east to west, suggesting that perhaps the wild olive in the west is feral rather than truly wild, but this study suggests that the wild olive spread out of 7 RPOPs, or reconstructed panmictic oleaster populations, in both eastern and western Mediterranean, possibly located in glacial refugia. Cultivated olives were domesticated in several RPOPs, and mediated geneflow in the wild species as they were spread around my humans. Has this business of glacial refugia been looked at for other cultivated trees in Europe?