Cascades Butterfly Project

Clodius parnassian, a high-altitude butterfly species NPS / Cathy Clark

MAY 2018

The Cascades Butterfly Project is a long-term monitoring program where citizen scientists (volunteers) and National Park Service Biologists monitor subalpine butterflies and plant phenology.

Butterflies and plants are sensitive indicators of climate change because air temperature influences their life cycles and their geographic distribution. As butterflies develop from egg to larvae to pupae and finally to full maturation, temperature thresholds may trigger these changes. Plant budburst, flowering, and fruiting times are also influenced by temperature and precipitation. Butterflies depend on plants as host plants – providing nectar or shelter for eggs and developing larvae.

Butterfly survey crew on Sauk Mountain NPS

Climate models project warmer summers, earlier snowmelt, more frequent forest fires, and changes in distributions of plants and animals, but not details on how species in our area will respond to these conditions. Studies in Europe and California have documented range shifts in butterflies in response to changing temperatures. Some species have moved northward or to higher elevations to track their optimal temperature range.

We are monitoring butterflies and plant flowering patterns to understand pollinators to understand how species in our parks are being influenced by warmer climates.

Map of survey sites

What Are We Doing?

We are monitoring butterfly abundance and plant phenology at ten permanent survey sites in two national parks and two national forests:

• North Cascades National Park Service Complex
• Mount Rainier National Park
• Mount Baker-Snoqualmie National Forest
• Okanogan-Wenatchee National Forest

Monitoring Objectives

• Monitor long-term trends in butterfly species richness and population abundance in select areas
• Monitor long-term trends in plant phenology
• Engage citizen scientists in collection of data and communication of information to the general public
• Provide field science internship opportunities to young scientists
• Provide data to national parks and forests to inform and adapt land management practices as climate changes

Butterfly survey at Easy Pass in North Cascades National Park. NPS

Monitoring Methods

• Butterfly abundance and plant phenology is monitored along ten 1-kilometer survey routes in two national parks and two national forests
• Monitoring is conducted weekly from snow-melt (~early July) until the first frost (~early September)
• Butterfly abundances are monitored using the Pollard Walk method
• Butterfly data are stored in partnership with the North American Butterfly Monitoring Network’s Pollard Base database (NABA) and Butterflies and Moths of North America

What Have We Found

Each year we have completed more surveys and documented more species with our volunteers and interns.

We have also found that peak butterfly abundance changes each year as snowmelt and summer temperatures change. In the graph below you can see the total number of butterflies found each week on surveys of Sauk Mountain in the Mount Baker-Snoqualmie National Forest. Notice the light blue line for 2015 which was a very warm and dry year with early snowmelt. Butterfly numbers peaked July 2-18 – about 3 weeks earlier than most other years. The table lists the dates of peak butterfly abundances on each route for 2015, 2016, and 2017. We are busy analyzing plant flowering times, but they seem to follow a similar pattern (earlier in warm, dry years).

Butterfly abundance at Sauk Mountain, 2011-2017

Identifying a butterfly in Mount Ranier National Park NPS

For More Information

Learn about volunteering for the Cascades Butterfly Project

Protocols & Procedures

Rochefort RM and McLaughlin JF. 2017. The Cascades butterfly project: A protocol for monitoring subalpine butterflies and plant phenology in the Cascade Mountains of Washington. Natural Resource Report. NPS/NOCA/NRR—2017/1440. National Park Service. Fort Collins, Colorado

Rochefort RM. 2017. The Cascades Butterfly Project: Survey routes, standard operating procedures, and field forms. North Cascades National Park Service Complex. Sedro-Woolley, Washington

In The News

Bush, Evan. "Citizen scientists track effects of climate change in the Northwest." The Seattle Times 7 August 2017.

Where this belongs

• Mount Rainier National Park
• North Cascades National Park

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