Citizen Science

Citizen Scientists Help Uncover Changes in Butterfly Populations in the Cascade Mountains

October 19th, 2017 at 3:15AM

Regina Rochefort and citizen scientists pose with their butterfly nets.
Regina Rochefort (third from the right) and citizen scientists pose with their butterfly nets.

In the diverse and bustling ecosystem of the Cascade Mountains, Regina Rochefort from the National Park Service (NPS) has been busy gathering volunteers for the Cascades Butterfly Project, which is a collaboration between NPS, the U.S. Forest Service and other partners. Since 2011, volunteers have recorded the plants and butterflies in the area to understand how those species are affected by climate change.  

"Maintaining meadows and early seral vegetation is an important part of ensuring a diversity of healthy habitat on National Forests," said Phyllis Reed, a wildlife biologist for the Mt. Baker Snoqualmie National Forest, one of the sites where volunteers collect data. "A landscape with a diveristy in age and habitat type supports plants that a variety of pollinators are associated with." 

Butterflies and plants were chosen as the study subjects because they are monitored across the world, dependent on each other, and easy to identify. Most importantly, butterflies are sensitive indicators of a changing ecosystem. For example, changes in air temperature influence their growth, where they roam, and when their host plants bloom — important lifecycle factors that are affected by climate change.  

Because plants and animals in the mountains are adapted to long winters and short, mild summers, their high-elevation ecosystems are especially at risk. As the temperature warms, habitat with subalpine meadow conditions is expected to shrink, with butterflies emerging earlier in the spring. Biologists want to know whether butterflies and their host plants will continue to emerge in the same timeframe. 

Arctic Fritillary butterfly
Bolioria charicia, or Arctic Fritillary, photographed in Mount Rainier National Park. Photo by Walter Siegmund

“If the plants don’t flower at the same time the butterflies are depending on them, the butterflies may not get nectar. If the plants don’t get butterflies, they won’t be pollinated, so these are some of the questions we are trying to answer,” said Rochefort. “This will be our seventh summer doing this project, and even in that short time period, we’ve seen a pattern of butterflies having their peak abundance earlier in the season.” 

Melanie Weiss has volunteered since the project began, and is now a lead on one of the routes. She’s also on the board of the Washington Butterfly Association. 

“Two summers ago, it was so dry it looked like a blowtorch hit the Alpine Meadows,” said Weiss. “And the following year, there were some changes; this one particular butterfly that’s really beautiful—the Arctic Fritillary—was not as present as it had been up until that point. So I’m curious if it’s going to rebound this summer.” 

But only after years of looking at patterns can we be truly comfortable with saying that climate change is a factor in those shifts. The Cascades Butterfly Project is the only long-term study on butterflies and plant phenology in the region. It was important to begin the study before climate change advances further, said Rochefort, because we must record how our ecosystems are at the moment so we can compare them to our measurements in the future. 

The study has 10 sites shared between the North Cascades National Park Service Complex, Mount Baker-Snoqualmie National Forest, Mount Rainier National Park, and Okanogan-Wenatchee National Forest. With so many sites, citizen scientist volunteers are crucial in gathering an amount of data that would be otherwise infeasible without a large crew and plentiful funds. The volunteers visit the sites weekly from snow-melt (early July) until the first frost (early September). 

A map of the ten survey routes.
A map of the ten survey routes.

When recording data, they survey using a “Pollard Walk”, and begin by imagining there is an invisible box in front of them that is five-by-five meters.

“And as you walk at a slow pace—they call it a wedding march pace— you document the species of every butterfly that flies through this imaginary box,” said Rochefort. “Some butterflies, like swallowtails, are large enough that you can figure out what they are as they fly by. But for others, we need to catch and release. We have a net to catch the butterfly and look at it either in the net or in a plastic jar to determine what it is.” The volunteers then record the species and number of butterflies, the plants in the area, and whether the plants are flowering. 

Along with nets, volunteers can also catch butterflies with a snap of their camera. Even if they are hiking alone, the volunteers are encouraged to take photos of butterflies within the study areas and upload them to the Butterflies and Moths of North America Project website. Through the website, butterfly experts can identify the type of butterfly in the picture and add that information to their database. The data is also stored in the North American Butterfly Monitoring Network’s PollardBase database (NABA).  

Whatever task they have, volunteers are excited to engage with experts and learn more about the biology of their area. Familiar trails become something new—a way to feed their curiosity while contributing to science. 

“Last year, we had a great day with these two little girls—they looked like they were about five or six—and they were so interested in learning about butterflies,” said Rochefort. “But I’ve also met people that are in their 80’s and still hiking, so we get a really wide range of people out there.” 

With the help of citizen scientists, the Forest Service and NPS continue collecting long-term data about butterflies fluttering around the Cascade Mountain meadows. Though no clear conclusions can be drawn right away, time will show patterns in what the volunteers collect. Their work can be used as a baseline for future climate studies and by land managers to protect at-risk species. The project is also one of 13 citizen science projects gathering butterfly data across several states (coordinated by Dr. Leslie Ries of Georgetown University) which allows for a comparison of results from different parts of the country.