Yet another study sheds light on the impact of human-caused climate change. Biologists from the US have recently concluded that flower colours across the world have become darker on the UV spectrum, owing to the rapid degradation of the ozone layer in the 20th century. The paper was published in the journal Current Biology.
Collecting samples from all over the world from the past 75 years, they concluded that UV-absorbing pigmentation has increased at all locations- at an average of 2% per year.
Such changes come about naturally and protect the flowers, like a sunscreen, from harmful ultraviolet (UV) rays, which have increased due to ozone layer degradation.
UV light cannot be seen by the naked human eye, but such changes stand out like a beacon to pollinators. If the UV pigmentation were to increase in the flower, then it would appear darker to the pollinators than it used to be when the UV pigmentation was lower, because the pigments would absorb more light in that spectrum.
“These pigment changes may help protect pollen, but pollinators might miss the flowers entirely” said a plant biologist at Harvard University.
One of the more curious findings in the research paper hinted that UV pigmentation might play a role in regulation of flower temperature, suggesting that global warming may additionally impact such pigmentation.
“This has implications for plant reproduction of both native wildflowers and domesticated crop species that have UV floral patterning like canola and sunflowers. Altered UV floral colouration has the potential to disrupt pollination services” says Matthew Koski from Clemson University, one of the authors of the study.
Koski also said that temperature change and ozone exposure at different places were significant factors in explaining the increasing pigmentation of the same species globally.
The work provides evidence that anthropogenic climate change is affecting global flower UV colouration.