Phenology records reveal far more more than temperatures. From bud break to bloom date, nesting to migration, that data that once informed farmers and hunters now can help Minnesota scientists tracking climate change.
ANNANDALE – Underneath a lacy curtain of lime-green basswood leaves, the group budding of phenologists squinted first at the emerging foliage, and then at what seemed to be an extensive checklist.
Breaking buds. Leaves. Which one. How many of each.
University of Minnesota environmental education professor Stephan Carlson pulled a branch to eyeball height. The group of Minnesota Master Naturalists closed in, considered whether the petiole — the stem that connects leaf to branch — was visible. If so, it was a leaf, even if that leaf remained tightly furled.
Phenology — how plant and animal life cycles such as nesting and flowering are influenced by climate and seasonal variations — has long been tracked by individuals. Phenology plays into planting, harvesting and hunting. Some keep track just for fun. Now those observations can play a role as scientists track climate change.
During a session at the annual Minnesota Master Naturalist conference last month near Annandale, Carlson and University of Minnesota Extension forester Eli Sagor explained how records kept by people across Minnesota might be used.
"We've always planned our lives around phenology," Sagor said.
While predicting the future remains impossible, watching how plants and trees respond to a warming climate — possibly with changes in the length of growing season, possibly with changes in a species' range — will at least allow scientists to more closely monitor the shift.
"We're likely to see a lot more change than other places," Sagor said.
That's because Minnesota contains three ecological regions from southwest to northeast: tallgrass prairie, Eastern broadleaf forest and boreal forest. That puts everything here near the edge of its range. Scientists predict a warming climate will push those ranges northeast.
"We know we've got changes happening. We don't know all the ways it's going to affect us," Sagor said.
Phenology records will help track if range shifts are occurring, where and to what degree. As an example, Sagor noted the incursion of red maple into the Boundary Waters Canoe Area Wilderness, a place where low temperatures previously kept the species at bay.
"We can look a lot at climate models, but it can be really hard to relate to," Sagor said. "We tend to trust data that we can relate to."
The date the trees leaf out, for example. Simple to comprehend. Possible to directly observe (at least once you get the hang of what is and is not a petiole).
Connections go beyond trees. There are the dates migratory songbirds and insects return. If birds precede insects, the birds may starve. The same holds true for bees and blooms.
"We need to know not just is the temperature changing, but what's changing with it and where," Sagor said.
To that end, a group of about 20 phenologists from across the state last year got together and determined from which species they could extract the most information.
The seven: red maple, common lilac, Eastern bluebird, monarch butterfly, tamarack, common loon and ruby-throated hummingbird.
"We want a lot of different people looking at the same thing in the same way," Sagor said.
Back outside with the basswood, Carlson stressed that it's possible to start recording observations midway through the growing season. The idea is to choose a single specimen to record. It could be in a front yard, workplace or on a frequently walked route.
Another option for those tracking a specimen new to them: Simply observe for the first year to get an idea of what to expect when.
University of Minnesota Extension is using Nature's Notebook, the National Phenology Network's online database, as its vehicle for recording phenological observations for those seven species. The site also defines terms to be observed and explains how to track them.
Meanwhile, an $180,000 Legislative-Citizen Committee on Minnesota Resources grant available July 1 will allow researchers to digitize handwritten records from which data can be extracted — decades worth of data, in some cases, that will add perspective.
Find more about Nature's Notebook and how you might contribute to the National Phenology Network's online database. (Submissions are not limited to the seven priority species in Minnesota.) Go to http://usanpn.org.
In Minnesota, phenologists will be gathering information on seven species to help build knowledge of climate change effects. Data will be recorded using Nature's Notebook, the National Phenology Network's online database. Here are the seven species they will watch:
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