Wildflowers in the Balance

Research critical to climate modelers, management agencies.

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By Marlene Cimons, National Science Foundation

For nearly 40 years, the wildflowers of Crested Butte, Colo. have given scientists important clues about the harmful effects of the Earth’s changing climate, especially on plant species and their pollinators, such as bumblebees, hummingbirds and butterflies.

Flowering plants and their pollinators have a vital but delicate relationship that ultimately affects much of what humans and wildlife eat. Any disruptions in this balance could be an economic catastrophe.

“What will happen to these populations of wildflowers if they are no longer making seeds?” said David Inouye, a University of Maryland professor of biology who is leading the study, which is based at the Rocky Mountain Biological Laboratory. “These flowers are resources for herbivores, pollinators, and grazing animals.”

The seasonal blooming of the plants, which grow 9,500 feet above sea level, is a sensitive indicator of the consequences of climate change, and their growing patterns are closely tied to snow melt, which has been changing dramatically over the past ten years. Less snow has been falling, it has been melting earlier, and Spring has been growing warmer.

The impact of this on mountain ecology could be dire, particularly for the food supply, which is dependent on phenology—the timing of seasonal events—and pollination.

“The date of the last hard frost hasn’t changed, meaning there are often buds now when the last frost hits,” said Inouye, who is currently on leave from the university to serve as program director in the population and community ecology cluster in  the National Science Foundation’s division of environmental biology.  “Buds are sensitive. If they are hit by frost, there won’t be any flowering.” 

Moreover, frost also can hurt insect species populations. In the case of one type of butterfly, for example, the Mormon Fritillary, the amount of nectar it can gather will affect the number of eggs it is able to lay.  

Scientists believe that the information produced by this research will improve their understanding of these environmental changes, and enable them to design counteractive measures.

The research already has shown long-term trends toward earlier flowering, lower flower production, and a growing “temporal” gap between early and late-flowering species, that is, the potentially destructive relationship that results from early snow melt, premature start of the growing season, and the date of the last hard frost. 

“If you are growing fruit trees at high altitudes, it’s been a few years since there has been a good crop of apricots or cherries, which are some of the earliest fruit trees to flower,” Inouye said. “If you have a warm spell in April, followed by a hard freeze in May, you will lose these crops.”

Because of the possible economic ramifications on agriculture and the security of the food supply, the research is funded by a $448,995 National Science Foundation grant as part of the American Recovery and Reinvestment Act of 2009. It supports the research of four scientists, as well as the education and training of ten undergraduate students, three graduate students, five postdoctoral fellows and five high school teachers. 

In addition, the work will almost certainly bolster the local economy. Crested Butte, which has been designated the official wildflower capital of Colorado, sponsors a major wildflower festival every year that draws hundreds of tourists. Visitors come to this historic and picturesque town to view the flowers, hike in the mountains and go birding, and participate in nature-based courses.

A hard frost could destroy early budding dominant flower species that cover the meadows, a popular tourist attraction. “There are over 100 different species that form an important part of the ecology of those mountain meadows,” Inouye said.

Inouye began his research in 1973, while still a graduate student. He set up a series of two meter-square plots of land, and counted every flower that bloomed in them every other day for the whole summer.  He continues to monitor 30 plots in four habitats, and observes the growing behavior of more than 95 plants species.