Climate change has been modifying the timing of recurrent plant life-cycle events, thus critically affecting the ecosystem.
Changes in climate affect the timings of various points in the life cycle of plants, including when flowers bloom in spring and when leaves wither in autumn.“We are like autumn leaves on branches,” Italian poet Giuseppe Ungaretti wrote in his 1918 poem Soldati , on the tragedy of human life and war.
Specifically, plants use a set of triggers to synchronize the timings of growth and reproduction with favorable environmental conditions. Japan’s Sakura or cherry blossom season is one of the most evident proofs of this shift. Dating back to the ninth century, the date of flowering, which defines the festival’s timing, has been anticipated in the last century by the rise in average temperatures.
At the end of the growing season, plants develop dormant buds to protect the sensitive meristematic cell layer — tissue in which cells maintain the ability to divide throughout the life of the plant — and suspend activity. Dormancy is an adaptation mechanism evolved in climates with seasons to escape harsh winter conditions.
However, an earlier growth reactivation increases the risk of damage due to late spring frosts, and lengthening of the growing season increases the risk of damage by early autumn frosts. Climate change can also cause mismatches between plants and their pollinators. Bumblebees represent one of the most important pollinators for several wild species and many varieties of enormous agricultural interest. Bumblebees, given their low heat and cold tolerance, are particularly sensitive to environmental conditions. For this reason, the projected climatic risk for this species is extremely high.