A new study published in Ecology Letters shows that climate change may disrupt this delicate balance in an unexpected way. While scientists have long known that rising temperatures cause plants to flower earlier, researchers at the Hebrew University of Jerusalem have now discovered that the timing of drought may be just as important as the amount of rainfall itself.

Led by doctoral students Barel Tsafon and Or Gross, under the guidance of Prof. Niv DeMalach, all from the Faculty of Agriculture, Food and Environment at Hebrew University, the researchers found that droughts occurring at different times of the growing season have dramatically different effects on flowering and on the way plant species interact with one another.

To investigate, the team grew thousands of plants from five common Mediterranean species in a large greenhouse experiment. The plants experienced identical reductions in water, but the drought occurred either at the beginning, middle or end of the rainy season. Some plants were grown alone, while others were grown together to examine how neighboring species influence one another.

Two shifts in flowering

The study uncovered two major findings.

First, plants growing alongside other species altered their flowering schedules, with each species tending to bloom at a different time. This reduced overlap between species and may help lessen competition for resources. The finding challenges the long-held idea that this type of "niche separation" develops only over evolutionary time, showing instead that plants can rapidly adjust their flowering without any genetic change.