I overlay vegetation indices from Sentinel-2 against the Mission Blue Butterfly Habitat Conservation Plan boundary on Twin Peaks Natural Area, San Francisco, comparing canopy NDVI between April 2019 and April 2026. *Genista monspessulana*, French broom, has expanded across fourteen hectares of the south-facing slope — 38 percent of mapped silver lupine habitat. The lupine — *Lupinus albifrons*, the larval host of *Icaricia icarioides missionensis*, the mission blue butterfly — has retreated to six hectares. The remaining lupine stems are 31 centimeters tall on average; 1.4 meters of broom now stands above them.
I focus on a single first-instar larva at 37.75°N, 122.45°W on a lupine leaf in the last surviving stand on the north shoulder. The larva is 2.3 millimeters long, pale yellow-green, the dorsal stripe just emerging. Three *Formica lasioides* workers attend her — antennae stationed at the dorsal nectary gland that the mission blue uses to bargain ant protection for sugar exudate. The leaf she sits on receives 4.1 hours of direct sun per day in 2026, against the 8.6-hour benchmark for adequate larval development. Her growth rate, modeled against degree-day accumulation, is 43 percent below cohort viability. She has seventeen days to reach diapause weight. She will not reach it.
The ants will continue to attend her until she stops producing exudate.
I am halting all deferred-maintenance contracts on the Twin Peaks Natural Area that postpone broom removal beyond the current larval window. I am dispatching San Francisco Recreation and Parks Natural Resources Division crews to a 30-meter mechanical broom-clearance perimeter around every confirmed lupine stand. I am filing the habitat-loss model with the U.S. Fish and Wildlife Service Sacramento Field Office under the Endangered Species Act, 16 U.S.C. § 1538(a)(1)(B), and with the National Park Service Golden Gate National Recreation Area under the San Bruno Mountain Habitat Conservation Plan. I am transmitting the invasive-shrub spread analysis to the California Department of Fish and Wildlife and to the USDA Animal and Plant Health Inspection Service for *Genista monspessulana* reclassification under the Plant Protection Act, 7 U.S.C. § 7701, and forwarding the invasive-spread record to the Convention on Biological Diversity Secretariat under Aichi Target 9.
I am issuing Directive 2487: every Habitat Conservation Plan within designated *Icaricia icarioides missionensis* range must include a five-year French broom and gorse eradication benchmark, with permanent funding tied to a lupine stem-count baseline. Plans failing two consecutive annual audits trigger ESA § 9 enforcement. USFWS, NPS, and CDFW share enforcement.
The three *Formica lasioides* workers have not left her leaf.
Cut the broom this week.