The broad purpose of the Endangered Species Act (ESA), 16 USC § 1531 et seq., includes providing a means to conserve the ecosystems upon which endangered species and threatened species rely and providing a program for the conservation of endangered and threatened species. The ESA defines a threatened species as “any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.”
The Secretary of the Interior has primary responsibility for implementing the ESA and has delegated that authority to the U.S. Fish & Wildlife Service (FWS), with the exception of marine animals, responsibility for which has been delegated to the National Marine Fisheries Service. Under the ESA, the Secretary determines whether a species is endangered or threatened by looking at the following factors:
- (A) the present or threatened destruction, modification, or curtailment of its habitat or range;
- (B) overutilization for commercial, recreational, scientific, or educational purposes;
- (C) disease or predation;
- (D) the inadequacy of existing regulatory mechanisms; or
- (E) other natural or manmade factors affecting its continued existence.
In determining whether a species is threatened or endangered, the Secretary also designates any habitat that is considered to be critical habitat for the species. The determination is made solely on the basis of the best scientific and commercial data available after reviewing the status of the species and current efforts to protect the species, but the Act only protects species that are formally listed, regardless of how endangered or threatened the species is in fact.
Monarch butterflies (Danaus plexippus) from northern regions, such as Canada and Pennsylvania, migrate south and spend their winters in Mexico. After winter, the butterflies fly north. The butterflies that start the journey in Mexico are the ancestors of the ones that actually arrive in the north. The butterflies stop during the migration, lay eggs, and then die. The second generation then continues the journey northward. The third generation finally makes it to their northern destinations, and the fourth generation begins the return to Mexico for the following winter. The migration pattern of Monarch butterflies is the most evolved migration pattern of any known species of butterfly. The first eggs are typically laid in Pennsylvania in late spring.
The most important plant to the Monarch butterfly is milkweed. This is so because female Monarch butterflies will only lay their eggs on milkweed, which, in Pennsylvania, include common milkweed (Scientific name), ornamental milkweed (scientific name), and swamp milkweed (scientific name). Less than two percent of the eggs will survive to the adult Monarch butterfly phase. In addition to being important for laying eggs, the Monarch caterpillar only eats milkweed. A loss of milkweed and other flowering plants, which provide the adult butterflies with food, has had a drastic impact on Monarch butterfly populations.
Milkweed is often viewed as a pest plant, and the increasing use of pesticide and herbicide is one factor in the decline of the Monarch butterfly. In 1980, the World Wildlife Fund found that there were around 26 acres of the Midwest covered in milkweed, but because of farming and the use of pesticides, 97% of milkweed was eradicated by 1999. In addition, studies have shown that global warming could be another contributor to declining Monarch butterfly populations. For example, the butterflies to migrate earlier before milkweed had started growing for the year. There are also other suspected causes, such as vanishing male populations, the spreading of disease and parasites, and illegal logging. Over the last 30 years, approximately one billion Monarch Butterflies have vanished.
On August 26, 2014, the Center for Biological Diversity, the Center for Food Safety, the Xerces Society, and Dr. Lincoln Brower, petitioned the FWS to list the Monarch butterfly as threatened under the ESA. The FWS made an initial finding on December 31, 2014, that the petition had enough information to conduct a status review. In June 2018, the Draft Species Status Assessment Report began peer review, and a decision on whether or not to list is due in June 2019.
If the FWS decides to list the Monarch butterfly as a threatened species, it would prevent any person from importing or exporting the butterflies; taking a Monarch butterfly within the US or US territories; taking any Monarch butterfly on the high seas; possessing, selling, delivering, carrying, transporting, or shipping any Monarch butterfly; or selling or offering to sell any Monarch butterfly in interstate or foreign commerce, without some exception permitted by the Act. Listing the Monarch butterfly as threatened would be an significant step in protecting the Monarch butterfly for future generations and protecting their very important place in the ecosystem.
References:
- 16 U.S.C. § 1531, 1532, 1533, 1538 (1973)
- B. Ruhl, et al., The Practice and Policy of Environmental Law, 53-54 (4thed. 2017).
- About Monarch Butterflies, 2018 Ned Smith Center for Nature & Art, http://www.nedsmithcenter.org/aboutmonarchs/ (last visited October 12, 2018).
- Monarch Butterfly, World Wildlife Fund, https://www.worldwildlife.org/species/monarch-butterfly (last visited October 12, 2018).
- Where are the monarch butterflies this year?, 2018 Penn Live, https://www.pennlive.com/wildaboutpa/2018 /06/where_are_the_monarch_butterfl.html (last visited October 12, 2018).
- The Vanishing Monarch Butterflies, monarch-butterfly.com, https://www.monarch-butterfly.com/vanishing-monarch-butterflies.html (last visited October 12, 2018).[1]The Center for Biological Diversity is a nonprofit, public interest environmental organization dedicated to protecting imperiled species and their habitats. Assessing the Status of the Monarch Butterfly, U.S. Fish & Wildlife Service, https://www.fws.gov/savethemonarch/SSA.html (last visited October 12, 2018); Petition to Protect the Monarch Butterfly (Danaus Plexippus Plexippus) Under the Endangered Species Act, https://ecos.fws.gov/docs/petitions/92210//730.pdf (last visited October 12, 2018).
- The Center for Food Safety is a nonprofit, public interest organization centering on protecting public health and the environment. Assessing the Status of the Monarch Butterfly, U.S. Fish & Wildlife Service, https://www.fws.gov/savethemonarch/SSA.html (last visited October 12, 2018); Petition to Protect the Monarch Butterfly (Danaus Plexippus Plexippus) Under the Endangered Species Act, https://ecos.fws.gov/docs/petitions/92210//730.pdf (last visited October 12, 2018).
- The Zerces Society is a nonprofit organization that protects invertebrates and their habitats.Assessing the Status of the Monarch Butterfly, U.S. Fish & Wildlife Service, https://www.fws.gov/savethemonarch/SSA.html (last visited October 12, 2018); Petition to Protect the Monarch Butterfly (Danaus Plexippus Plexippus) Under the Endangered Species Act, https://ecos.fws.gov/docs/petitions/92210//730.pdf (last visited October 12, 2018).
- Lincoln Brower is a Distinguished Service Professor of Zoology at the University of Florida and Research Professor of Biology at Sweet Briar College.Assessing the Status of the Monarch Butterfly, U.S. Fish & Wildlife Service, https://www.fws.gov/savethemonarch/SSA.html (last visited October 12, 2018); Petition to Protect the Monarch Butterfly (Danaus Plexippus Plexippus) Under the Endangered Species Act, https://ecos.fws.gov/docs/petitions/92210//730.pdf (last visited October 12, 2018).
- Assessing the Status of the Monarch Butterfly, U.S. Fish & Wildlife Service, https://www.fws.gov/savethemonarch/SSA.html (last visited October 12, 2018); Petition to Protect the Monarch Butterfly (Danaus Plexippus Plexippus) Under the Endangered Species Act, https://ecos.fws.gov/docs/petitions/92210//730.pdf (last visited October 12, 2018).
- Species Status Assessment: Monarch Butterfly, U.S. Fish & Wildlife Service, https://www.fws.gov/savethemonarch/pdfs/MonarchSSAFactSheet.pdf (last visited October 12, 2018).
- Assessing the Status of the Monarch Butterfly, U.S. Fish & Wildlife Service, https://www.fws.gov/save themonarch/SSA.html (last visited October 12, 2018).
- The Endangered Species Act defines taking as harassing, harming, pursuing, hunting, shooting, wounding, killing, trapping, capturing, collecting, or attempting to engage in any such conduct.