Mediterranean pasture dynamics: the role of germination.

Meteorological patterns have a decisive influence on the inter-annual dynamics of therophyte pastures under Mediterranean climatic conditions. The germination behaviour of annual pasture species was studied by subjecting two collections of seeds taken from plants and soil-seed banks to two phytotron-simulated weather patterns: early and late autumn rains. Species from these pastures were arranged along a gradient of sensitivity to temperature on the arrival of the first persistent rain. This sensitivity was manifested in both the total germination success of the species and the germination time profile. The different germination patterns of the species can provide competitive advantages depending on the autumn weather conditions.