You may have noticed the change in your backyard or along your favorite hike. Snow might be melting a little earlier than in the past, and flowers are poking their heads through the soil a little sooner. Maybe your lilacs bloom before you remembered years ago.
If you did notice, a scientific study now backs it up.
High mountain flowers in the Rocky Mountains are blooming up to a month earlier than they did 40 years ago, according to research by University of Maryland Biology professor David Inouye. His paper,“Shifts in flowering phenology reshape a subalpine plant community,” was published recently in the Proceedings of the National Academy of Sciences. The implications of his findings could range from wildflowers changing where and when they grow to others dying off altogether.
“When I started this project in the early ‘70s, no one talked about climate change, nobody was thinking about it,” he said.
In 1973, as a graduate student at the Rocky Mountain Biological Laboratory in Colorado, Inouye was working with hummingbirds and bumblebees. He wanted to know what flowers the two creatures used for nectar and pollen, and he and several other students cordoned off 2-by 2-meter plots in various areas in the mountains. They walked around to their plots every other day for the entire growing season, counting and cataloging which plants they noticed growing, how many flowers the plants grew and when they bloomed.
“At the end of the year, we had interesting data and thought, if we did it more than a year we would have more insights about how different flowering is from one year to the next,” he said. “Every year I kept going and there were additional insights gained and more perspectives possible.”
The other students working with him eventually dropped off. He took over their plots, gathering 30 sections and monitoring about 120 different flowering species.
The National Science Foundation has paid for much of his research, including for the next five years.
“We were interested in questions like how many species are in bloom at the same time during the summer and how many bloom in a 2-by-2 plot and when does flowering begin and end,” he said. “It’s a pretty simple question and data to collect, but I think the real value in the data set is now its longevity.”
The work was done in Colorado, but the 60 plant species in the study are widespread in the Rocky Mountains and found in many Wyoming mountain ranges, said Bonnie Heidel, botanist at Wyoming Natural Diversity Database.
Birds and bees
Inouye found several key results from his data, and said they are likely also occurring in Wyoming’s mountains.
While wildflowers are blooming up to a month earlier than they did 40 years ago, the date of the season’s last hard frost has not changed significantly.
This means instead of a frost hitting smaller plants barely poking through the ground, it is killing buds from flowering ones. The changes are already appearing in some farmer’s markets because of frosts to apricot, cherry and peach trees, he said.
The other important observation includes those bees and hummingbirds he initially set out to research.
Bumblebees aren’t coming out of the ground from their winter hibernations and hummingbirds aren’t returning from their migration early enough to compensate for the change in flowering.
Some flowers that need birds and bees are finished flowering by the time the creatures arrive. If the flowers aren’t pollinated, they don’t spread their seeds and reproduce.
“This would make some flowers go extinct, and we will see new kinds of relationships arising,” he said.
Fewer plants to pollinate could lead to less food for bees and hummingbirds.
This summer, Inouye and other researchers plan to put radio transmitters on hummingbirds in the area to find nests and monitor the timing of nesting to see how it coincides with blooms.
The information could not only be useful to researchers studying flowers or farmers understanding the growing season, but also to scientists working with species dependent on the flowers. Changes in some butterfly populations, for example, can now be traced back to changes in the timing and abundance of the flowers they visit for nectar, he said.
While Inouye might have one of the most complete lists of data in the West, he’s not the only one trying to collect the information.
Organizations like Project Bud Burst and the USA National Phenology Network are asking people to report their own observations. If you hike that same trail around the same time each year, you can now tell researchers what you see.
“When you saw the first lilac or dandelion, that information anyone can collect,” he said. “You don’t need a Ph.D. If you have enough years of people recording that information it becomes a tremendously valuable resource.”