Dr. David Inouye

David Inouye

Dr. David Inouye examining
Aspen sunflowers

Viewing mountain wildflowers is a favorite seasonal pastime for many. And while lots of people make return visits every year to a favorite location, few people have spent 37 summers making careful observations of wildflowers as part of an ongoing scientific study. Since 1973, Dr. David Inouye has done just that. He has spent his summers at the Rocky Mountain Biological Laboratory (RMBL), at the former ghost mining town of Gothic in Colorado. David has been carefully monitoring 100 different plant species including spring beauties, aspen sunflower, and larkspurs, as well as introduced dandelions. Over the decades of his study, he has observed changes in the timing of phenophases for many of the wildflowers he observes. David's findings are of interest to scientists studying climate change.

The timing of the high-altitude growing season is controlled primarily by when the winter snowpack (up to 8 feet!) melts. Snowmelt can range from late April to mid June, depending on how much snow falls the previous winter and how warm the spring is. A trend toward warmer springs and lower winter snowfall has resulted in earlier growing seasons in the past decade. Thus, flowering has been occurring earlier. One consequence of this trend is that more wildflower species have buds by mid-June, when the last hard frost is still likely to occur, so that earlier snowmelt results in more frost damage to sensitive buds. Animal species are also responding to the changing environment in terms of their phenology. Marmots are ending their hibernation about a month earlier than they did 35 years ago, and robins are arriving for the summer breeding season almost a month earlier. One pollinator, a bumble bee species, has moved up in the Gothic region of the Rocky Mountains almost two thousand feet over the same time period. It appears that some wildflowers are also changing their altitudinal distribution too. These changes happen slowly enough that it takes long-term studies to document the ongoing changes.

David's wildflower observations are unusual not only for the length of his study but for the frequency with which he counts the flowers – every other day for the length of the growing season (almost four months). He walks about two miles on his circuit to the 30 2x2 meter plots in which he counts every flower, which takes about half a day during the peak of the season. His observations are still recorded with pen and paper, but are now also documented in computer spreadsheets, a new innovation since he began the study in 1973. This also makes it easy for him to share the data with other scientists, which he often does. He points out that although long-term records can provide unique insights, it's never too late to start collecting phenological data, even from your own backyard, and sharing them via Project BudBurst. The valuable observations of marmots and robins were made by a non-scientist friend of David's who lives and works (as a business manager) at RMBL, who out of his own interest began recording those observations 35 years ago.