On December 12, 2024, the United States Fish and Wildlife Service (“FWS”) released its long-awaited proposed decision to designate the monarch butterfly as a threatened species under the Endangered Species Act (“ESA”). This decision has been a decade in the making and has been closely watched by the agricultural industry. The proposed listing decision is highly detailed and includes extensive exemptions for agriculture and citizen conservation efforts. However, certain key issues such as pesticide usage remain unaddressed. A comment period on the proposed rule will be open through March 12, 2025. The butterfly will not be formally listed under the ESA until a final rule is issued.
Background
The effort to list the monarch butterfly under the ESA began in 2014 when various environmental groups submitted a petition to list the species to FWS. Understanding the relevant law is helpful to understanding how the 2014 petition eventually resulted in a proposed rule.
Endangered Species Act
Congress passed the ESA in 1973 to conserve endangered species and the ecosystems on which those species depend. 16 U.S.C. § 1531(b). The law is jointly administered by the FWS and the National Marine Fisheries Service (“NMFS”) (collectively, “the Services”), both of which are responsible for identifying species to list as either threatened or endangered under the ESA. A species will be listed as threatened if it is “likely to come an endangered species within the foreseeable future,” while a species will be listed as endangered if it is “in danger of extinction throughout all or a significant portion of its range[.]” 16 U.S.C. § 1532(6), (20).
A listing decision can be initiated in one of two ways. Either the Services can decide on their own to initiate the listing process for a particular species, or a private party can submit a listing petition to the Services. 16 U.S.C. § 1533(b). Once the Services receive a listing petition, they have twelve months to determine whether listing is appropriate. 16 U.S.C. § 1533(b)(3)(B). If the Services fail to act within that twelve-month window, whoever submitted the petition can initiate a lawsuit to enforce the deadline. 16 U.S.C. § 1540(g)(1)(A).
When determining whether to list a species, the ESA directs the Services to consider five factors: the present or threatened destruction, modification, or curtailment of a species’ habitat or range; overutilization of a species for commercial, recreational, scientific, or educational purposes; disease or predation impacting a species; the inadequacy of existing regulatory mechanisms to protect a species; and any other natural or manmade factors affecting a species’ existence. 16 U.S.C. § 1533(a)(1). Any one of these factors can serve as the basis for a listing decision.
Once a species is listed under the ESA, it becomes illegal to “take” any member of the species. The ESA defines “take” as any attempt to “harass, harm, hunt, shoot, wound, kill, trap, capture, or collect” any listed species. 16 U.S.C. § 1532 (19). When a species is listed as endangered, the full prohibition on take is automatically applied to the species. The ESA does not grant the Services power to exempt any activities from being considered take of a species once a species is classified as endangered. However, when a species is listed as threatened, the ESA allows the Services to tailor the protections the species receives. 16 U.S.C. § 1533(d). This means that the Services can choose to exempt certain activities from being considered take of a species. For example, when FWS listed the Dakota skipper butterfly as threatened in 2014, it exempted various agricultural activities from being considered take of that species. Such exemptions are commonly referred to as 4(d) rules.
Additionally, the ESA allows the Services to designate critical habitat for any listed species. “Critical habitat” refers to specific geographic areas that are either occupied by a species at the time it is listed and contain all elements that are necessary for the conservation of that species, or that are unoccupied by the species at the time of listing but are nevertheless essential for conservation. 16 U.S.C. § 1532(5). Once an area is designated as critical habitat, it receives its own protection under the ESA. Specifically, the ESA requires all federal agencies to ensure that any actions they authorize, fund, or carry out do not cause destruction of or adverse modification to designated critical habitat.
The Monarch Butterfly & Pathway to Listing
The monarch butterfly is a migratory butterfly species identified by its distinctive black and orange markings. In the United States there are two primary monarch populations located to the east and west of the Rocky Mountains. The Western population migrates from Canada and overwinters in tree groves along the California coast and in northern Mexico. The Eastern population migrates from Canada through the central United States before overwintering in Mexico. Monarch butterflies require habitat that contains both milkweed plants which the monarch uses as a larval host plant, and nectar plants which provide food for adult monarchs.
Over the last several decades, both the Eastern and Western monarch butterfly populations have been in steady decline. According to FWS, the Western population numbered in the millions during the 1980s but is now closer to 200,000 individual butterflies. Similarly, the Eastern population has decreased from estimates of 160 to 360 million in the 1990s to estimates of 18 million today. That population loss is largely what prompted a coalition of environmental groups lead by the Center for Biological Diversity to submit a listing petition to FWS in 2014.
In their petition to list the monarch butterfly, the petitioners claimed that the monarch should be listed under the ESA due to declining populations, habitat loss, and threats from pesticide exposure and climate change. Initially, FWS responded to the petition by determining that the petitioners had presented substantial information indicating that listing may be warranted. However, FWS failed to meet the twelve-month deadline to make a formal listing determination, which prompted the petitioners to file a lawsuit to compel FWS to set a deadline by which to issue a formal determination. Ultimately, FWS settled that lawsuit with an agreement to issue a listing decision for the monarch by 2020. To learn more about that lawsuit, click here. In December of that year, FWS concluded that the monarch butterfly was warranted for listing, but at that time precluded by higher-priority actions. This made the monarch butterfly a candidate species, meaning that FWS was required to review its status each year until it is no longer a candidate for listing either due to recovery or because listing the species is appropriate. After FWS’s most recent review of the monarch, it has determined that the butterfly is warranted for listing as a threatened species.
What’s in the Proposal?
The proposed decision to list the monarch butterfly as threatened under the ESA is a detailed document that includes both a designation of critical habitat and an extensive list of activities that would be exempt from the prohibition on take should the monarch be formally listed. The proposed exemptions would cover a wide range of agricultural activities.
The proposal highlights three primary threats impacting the monarch butterfly’s population: loss and degradation of its breeding, migratory, and overwintering habitat; insecticide exposure; and the effects of climate change. To address those threats and stabilize its population, FWS proposes the following goals: (1) achieve a significant increase in the availability of milkweed and nectar plans in monarch breeding and migratory areas; (2) protect and enhance overwintering habitat; (3) avoid and minimize impacts to monarchs and their habitat from insecticides and herbicides; and (4) maintain public support for the conservation of monarch butterflies.
Significantly, the proposed listing decision includes an extensive 4(d) rule. Under the proposed rule, the following categories of activity would not be considered take of the monarch butterfly: activities that maintain, enhance, remove, or establish milkweed and nectar plants within the breeding and migratory range of the monarch; implementation of comprehensive conservation plans and programs that address threats to the monarch; maintenance or improvement of overwintering habitat; vehicle strikes; non-lethal collection, possession, captive-rearing and release of 250 or fewer monarchs; non-lethal scientific research and education activities involving 250 or fewer monarchs; possession of dead monarchs; and the sale of 250 or fewer captively reared monarchs.
Particularly relevant to agriculture is the first category of activity which would exempt actions done to maintain, enhance, remove, or establish milkweed and nectar plants within the monarch’s range. FWS has specifically identified various agricultural activities that would fall under this category, including:
- Habitat restoration and management actions such as mowing and haying or the elimination of invasive plants or noxious weeds;
- Livestock grazing and routine ranching activities such as rotational grazing, patch-burn grazing, vegetation and invasive species management, the gathering and management of livestock, construction and maintenance of fences, and maintenance of livestock watering facilities;
- Routine agricultural activities such as plowing, drilling, disking, mowing, mechanical manipulation of agricultural land, operation of existing infrastructure, and routine conservation practices;
- Fire management;
- Silviculture practices and forest management activities;
- Maintenance, enhancement, remove, and establishment of milkweed and nectar plants on residential and other developed properties; and
- Vegetation management activities that remove milkweed/nectar plants during times of the year when monarchs are not present.
FWS added that “routine agricultural activities on lands already in use for agricultural production” would result in levels of milkweed loss that are considered “inconsequential to the conservation of the species.”
Along with the 4(d) rule, the proposed listing decision includes a designation of critical habitat. The designation is aimed at the Western population of monarchs and is focused on conserving overwintering habitat. FWS focused on sites that had high occupancy rates of overwintering butterflies during population counts conducted from 2013 – 2022. The result is a proposal to designate roughly 4,400 acres of critical habitat across seven coastal counties in central and southern California. Those counties include Ventura County, Santa Barbara County, San Luis Obispo County, Monterey County, Santa Cruz County, Alameda County, and Marin County. No areas outside of California have been proposed for critical habitat.
Finally, the proposed decision also includes a solicit for public comment on certain key topics. While proposed agency decisions typically hold public comment periods during which members of the public can submit comment on any aspect of the proposal, agencies can highlight topic areas that they are specifically seeking further input on. In the proposed monarch listing decision, FWS is requesting comment on how to address pesticide use under the 4(d) rule. Specifically, FWS is seeking comment on which pesticide uses and application methods result in exposure and adverse effects to monarchs, and whether those uses should be exempted from take as part of a 4(d) rule. FWS is also seeking comment on whether it should include any mitigation measures to lessen the effects of pesticides on monarchs, and if those measures should be tailored according to geographic location and times of the year when monarchs are known to be present. Currently, pesticide use is not included in the proposed 4(d) rule. It is uncertain whether pesticide use would be addressed in a final listing decision or in a separate rule.
Looking Ahead
The expansive 4(d) rule in the proposed monarch listing decision is a relatively novel approach to listing species under the ESA. The exemption of common agricultural practices and activities that modify or remove milkweed suggest that private landowners are seen as crucial to monarch butterfly conservation. However, the proposed listing decision is not a final decision and it does not address every area of concern. The comment period for this proposal will remain open through March 12, 2025. After that period ends, FWS will review the comments and at some point issue a final decision. With questions remaining about exemptions for pesticide use and possible mitigation measures, the comment period will be important for helping to reach a final rule.
To read the proposed monarch listing decision, click here.
To submit a comment on the proposal, click here.
To reach the text of the ESA, click here.
For more National Agricultural Law Center resources on the ESA, click here.