The warm fall has caused a delay in the blooming of the flowers. As some flowers failed to open in its usual time due to the warm previous fall. That phenomenon is now under discussion from the scientists.
Oddball spring flowers that seem unaffected by climate change — or have gotten it backwards — could be taking some cues from unusual autumns the year before.
Like their early flowering peers, plants in a new study show that many of these on-time and late bloomers also have had their timing shifted by a warming globe — but the paradoxical effects have just been more difficult to observe.
Climate change is bringing warmer and earlier spring times to meadows, mountain slopes and many other ecosystems worldwide, with many a bud bursting into bloom days or weeks earlier than in decades past. Yet a minority of plants continue to bloom at their regular time, and some even appear to delay their blooms, says Benjamin Cook of the NASA Goddard Institute for Space Studies in New York City. While some have suggested explanations for these contrarian plants’ out-of-step timing, the effect has been tricky to analyze.
Looking at plant bloom times in terms of both spring and fall temperature quirks, however, shows that some species are sensitive to signals from unusual fall temperatures, Cook and his colleagues report online May 21 in Proceedings of the National Academy of Sciences. Warmer fall temperatures may mask or delay any tendencies to bloom earlier in the spring.
Biologists have known that certain plants need a good chill over the winter before they thrill to the warming of spring and break out of dormancy to bloom. If weather doesn’t cool down as soon as it used to in the fall, then the chilling doesn’t start on time and there’s a delay in the spring response. Requirements for this cool-down time-out, called vernalization, are better known for crops and garden beauties than for most wild species.
To try to quantify how climate change tweaks vernalization for a wide range of species, Cook and his colleagues turned to a 47-year record (1954 through 2000) of the first bloom dates for 384 species growing near the same site around Chinnor, England. And to broaden the range, the researchers looked at 31 years of first blooms from 106 species around Washington, D.C.