The United States Fish and Wildlife Service says protections for monarch butterflies under the Endangered Species Act are necessary but less pressing than those for other species on the brink. The decision comes as biologists report the lowest numbers in history for the western population of monarchs, which overwinters on California’s coast.
The federal agency was compelled to consider listing monarchs by litigation from the Center for Food Safety, the Center for Biological Diversity and the Xerces Society, which rang the alarm about the decline of both the eastern population—which has declined over 70 percent—and the western population—which has almost disappeared—due to climate change, pesticide use and habitat loss. As the groups celebrated the validation of the species’ plight last week, West Marin organizations geared up to take action now.
Preliminary data on overwintering numbers in California was released last month by the Xerces Society, which conducts annual counts around Thanksgiving and New Year’s. Based on the Thanksgiving count, the group is projecting only 2,000 monarchs this year, down from around 30,000 in the last two years and less than 0.1 percent of numbers in the 1980s.
“It’s hard news to share: Monarchs were another casualty of 2020,” said Emma Pelton, a Xerces Society conservation biologist. “Following two record-low years, we entered the worst wildfire season in the West ever and really hot and dry conditions. There were already really vulnerable populations and we just saw them tank further. They weren’t set up for success, but we are disappointed that it has gotten this bad.”
Since local counting began in 1997, monarchs have been found in Marin at five overwintering sites in Bolinas—primarily on private property—in addition to one in Stinson Beach, two in Muir Beach, one at Fort Baker and one at the Marin Headlands.
So far this year, 150 monarchs were counted in Bolinas, five in Stinson Beach and two in Muir Beach. Across the Bolinas sites, 22,253 monarchs were counted in 2015, but that number dropped steadily to 328 in 2019. The Stinson site saw one monarch in 2018 and none last year; in 2015, there were 8,200.
Even more disheartening, the monarchs that survive the winter are typically far less than those counted in the fall. In the early 2020 count, the Xerces Society reported a 46 percent decline in numbers from the previous Thanksgiving.
Mia Monroe, a National Park Service ranger who started the counts in 1997 and coordinates efforts in Marin as a volunteer, highlighted the importance of protecting monarchs. “Monarchs are a keystone species: You take care of them and they help the web of life,” she said. “They catch our soul and they are so symbolic. It is about protecting monarchs but it is also about protecting health and biodiversity.”
Ms. Monroe recently collaborated with the Environmental Action Committee of West Marin to produce a report that identifies gaps in the regional response toward helping the species recover. The E.A.C. identified five key steps: protecting and managing overwintering sites, restoring breeding and migratory habitat, eliminating pesticide use, protecting summer breeding habitat and fall migration habitat outside of California, and filling research gaps.
Several groups engaged in monarch preservation locally took a survey included in the E.A.C.’s report, weighing in on what is still needed. Some of these groups include Marin Parks and Open Space, the Point Reyes National Seashore, the Marin Resource Conservation District, Marin Audubon Society and Marin Master Gardeners.
All respondents noted the importance of increased public outreach and education, especially regarding milkweed, which is the only plant monarchs will lay their eggs on and which monarch caterpillars eat. Milkweed declined nationwide beginning in the mid-1990s with the increase in the use of the herbicide Roundup; in response, concerned citizens and conservationists have taken to planting it everywhere.
But there are caveats about planting milkweed in Marin: It must be a native variety. Tropical milkweed, which is not native to California, has often been planted, but because it does not die back in the winter it leads the butterflies to breed when they should be hibernating; it can also support a parasite that’s harmful to the species. The E.A.C. report highlights the importance of Marin nurseries carrying only native narrowleaf milkweed.
Additionally, milkweed should be planted in breeding habitat in East Marin, but not on the coast. Other nectar plants can be planted on the coast, which can help sustain them through the winter. Some plants that are good for monarchs on the coast are yellow sand verbena, California goldenbush, Pacific gumplant and dune goldenrod.
“One of the most important things to emphasize is that individual actions for habitat support are just as important as large-scale habitat restoration,” said Morgan Patton, the group’s executive director. “They are primarily migrating through private property, and the action people take in their own gardens has an impact. Putting pesticides in your garden, planting tropical milkweed or else milkweed at all if you live on the coast, is going to have a really large impact on the butterflies.”
The E.A.C. made several specific recommendations for public agencies and nonprofits. These included creating an outreach program to provide education to property owners, mapping heritage roost sites, identifying where habitat has been lost and implementing mitigation and restoration projects, exploring public acquisition of parcels that are essential overwintering sites, and coordinating a community science study to document spring dispersal numbers to understand where butterflies go after departing Marin as the climate changes. The group suggested for East Marin identifying and protecting native milkweed patches as well as a citizen science project that would document breeding locations.
Had monarchs been listed as endangered last week, they would have received a host of new protections. Threats to their habitat would have had to be re-evaluated and actions taken by public agencies that impact their population reconsidered. Still, the Center for Food Safety saw the acknowledgement of the value of the species as progress: “warranted-but-precluded” findings require subsequent review each year until the agency undertakes a proposal or makes a “not-warranted” finding.
The Trump administration has given few species protections under the Endangered Species Act, while the United Nations found last year that over one million plant and animal species are at risk of extinction due to human activity. “This is the best result in the realm of reality from this administration and a huge victory,” said George Kimbrell, the legal director for the center. “The Trump administration would not grant a listing outright and dare crossing Monsanto [and] Bayer, but at the same time could not deny that in petitioning for their listing, we and our colleagues were right on the science and the law: Monarchs deserve to be protected.”
There are currently 161 species prioritized ahead of monarchs for listing. Last week, Fish and Wildlife decided that upgrading the status of northern spotted owls from threatened to endangered was warranted, but also would be delayed.