National park to apply herbicides in butterfly habitat restoration efforts

  • Sun Nov 5th, 2017 7:00am
  • News

Contributed image/NPS

Submitted by the San Juan Island National Historical Park

Ten new test plots at American Camp in San Juan Island National Historical Park will be treated with herbicide, weather permitting, in support of Island Marble Butterfly habitat restoration sometime between Oct. 31 and Nov. 3. This is the third year of a five year study that is attempting to increase the amount of suitable habitat present at American Camp for the Island Marble Butterfly, a candidate for the Endangered Species List. Glyphosate will be applied to 10 new plots and 10 existing plots below the Redoubt.

Following the successful prescribed burn of six plots on Young Hill on Oct. 5 the Exotic Plant Management Team from North Cascades National park will be treating 12, 10-by—meter sub-plots with Indaziflam and Rimsulfuron. These experimental burns, in conjunction with the herbicide treatment, are being tested to determine their effectiveness in removing non-native grasses that have over-taken the Gary Oak woodland.

Researchers and public land managers in many areas of the Pacific Northwest are using select herbicides to control non-native grasses in habitats similar to San Juan Island. The park is proceeding with caution and is committed to fostering native ecosystems without compromising the health of this biologically unique area. Areas treated with herbicides will be closed-off and clearly signed to keep people and their animals safe for approximately 10 days.

All affected trails will be signed during the application and for 24 hours thereafter and a crew coordinator will be available for questions on site, visit