The flowering time of alpine plants has advanced by nearly two weeks in the last 38 years, due to climate change, a study published in Proceedings of the Royal Society B has found.
Scientists from Duke University in North Carolina studied the flowering times of alpine mustard plants common to the U.S. Rocky Mountains from 1973 - 2011. They found that flowering time has advanced by 13 days owing to increasingly warmer winters and earlier snowmelt over this period.
Plants that reproduce, i.e. flower, earlier in the year, have the greatest fitness. This is because earlier reproduction means than offspring will have longer to grow in the milder temperatures. Plants that flower earlier, and can take advantage of the warm weather, are being selected for.
Climate change could further drive this selection, and promote even earlier flowering as temperatures continue to increase. Jill T. Anderson and her team predict that flowering will occur 0.2 to 0.5 days earlier in each generation. However, evolutionary response is likely to be much greater now than even 30 years ago because of rapidly changing climatic conditions. Thus adaptation will likely be necessary for long-term survival of species in the context of climate change.
This study confirms that adaption is taking place, but human-induced climate change may far outpace adaptive evolution. Even though earlier flowering plants are being evolutionarily selected for, this response has been limited. The temperature is rising earlier in the year at a greater rate than plants can adapt to flower earlier. The effect is so wide-spread, that even for species that grow in many different areas, if they cannot evolve fast enough to adapt to these changes, then they risk extinction.