A unique 39-year study of wildflower blooms in a Colorado Rocky Mountain meadow shows more than two-thirds of alpine flowers have changed their blooming pattern in response to climate change. Not only are half the flowers beginning to bloom weeks earlier, but more than a third are reaching their peak bloom earlier, and others are producing their last blooms later in the year. The bloom season, which used to run from late May to early September, now lasts from late April to late September, according to University of Maryland Biology Professor David Inouye.
The wildflower records, made up of more than two million blooms, show that flowering plants' response to climate change is more complex than previously believed, with different species responding in unexpected ways. The combinations of flower species that bloom together are changing too, with potential impacts on insects and birds. Studies that focus only on the date of flowers' first bloom as most do understate these changes, said Inouye, the senior author of a study published online March 17, 2014 in the Proceedings of the National Academy of Sciences.
Phenology, the study of the timing of seasonal events, is crucial to understanding how climate change is affecting plants, animals and the relationships that bind them into natural communities. To answer these questions, phenologists are collecting modern data and poring through old records like amateur naturalists' notebooks.
"Most studies rely on first dates of events like flowering or migration, because they use historical data sets that were not intended as scientific studies," Inouye said. "First flowering is easy to observe. You don't have to take the time to count flowers. So that's often the only information available. It has taken a lot of effort to get the comprehensive insights needed for this analysis, which helps us understand how ecological communities are going to change in the future."
|Contact: Heather Dewar|
University of Maryland