General stabilizing effects of plant diversity on grassland productivity through population asynchrony and overyielding. by Hector, A, Hautier, Y, Saner, P, Wacker, L, Bagchi, R, Joshi, J, Scherer-Lorenzen, M, Spehn, E, Bazeley-White, E, Weilenmann, M, Caldeira, M, Dimitrakopoulos, P, Finn, J, Huss-Danell, K, Jumpponen, A, Mulder, C, Palmborg, C, Pereira, J, Siamantziouras, A, Terry, A, Troumbis, A, Schmid, B, Loreau, M