Timing of germination can greatly affect species fitness especially in annual plant communities, thus plant species in strongly fluctuating and unpredictable environments have to maintain a persistent seed bank to avoid extinction. Theoretically, germination fractions should be positively correlated with amount and predictability of rainfall, however there is evidence that germination rates may also strongly depend on the density and composition of the seed bank.
We investigated germination rates and timing of 76 annual plant species growing along a steep climatic gradient in Israel. We compared germination behaviour in monospecific treatments vs multispecies treatments mimicking the natural community in which species grow. The main hypothesis we want to test is that species adapted to high levels of competition and limited resource availability will germinate faster in order to pre-empt space and resources and to optimize their chances of survival.