The Butterfly Effect: Prostrate Milkweed

Gina Yum

In February of this year, the U.S. Fish and Wildlife Service (USFWS) proposed a rule to list prostrate milkweed, a flowering plant native to Texas, as an endangered species. They also proposed to set aside 691.3 acres of land as critical habitat for this plant species in the Starr and Zapata counties of Texas. The government has valid reasons for wanting to protect such a plant. Prostrate milkweed is a vital food source for native bees, butterflies and other pollinators, many of which have seen steep declines in population. Unfortunately, according to the Center for Biological Diversity, there are only a meager 24 populations of the prostrate milkweed species left. What is more discouraging is 19 of those 24 populations are considered to be in “low” condition. Officials believe that listing prostrate milkweed as an endangered species could protect the habitats of important pollinators. This would especially benefit the monarch butterfly, an iconic butterfly species that prostrate milkweed has long acted as a host plant for. 

Environmentalists have been well aware of the critical state of prostrate milkweed for quite a while. There were petitions for prostrate milkweed to be listed as endangered under the Endangered Species Act released in 2007 and 2009. In 2009, the U.S. Fish and Wildlife Service concluded that the petition presented information that justified listing prostrate milkweed as endangered and decided a status review was needed. The fight to protect this rare plant species has been long and arduous. The Center for Biological Diversity (CBD) filed a lawsuit against the U.S. Fish and Wildlife Service in order to urge the USFWS to make quicker protection decisions for over 200 plant and animal species that are thought to be close to extinction, including the prostrate milkweed. According to the CBD, although 99% of species placed under the protection of the Endangered Species Act are kept from going extinct, it takes a lot of time to add animal and plant species to the endangered list, which makes recovery very tedious. The Center for Biological Diversity lawsuit was filed just before the FWS released this proposed rule for the milkweed species.

If this proposed rule were to be finalized, it would provide a tremendous victory to environmentalists. Prostrate milkweed would be added onto the List of Endangered and Threatened Plants, and the protections of the Endangered Species Act would apply to the plant. This would prohibit federal actions from hurting the plant, the “take” of prostrate milkweed, as well as the potential interstate or international trade of the milkweed species.

This is very necessary considering that human activity is the main contributor to the current poor state of the milkweed species. Human activity has made prostrate milkweed face unnecessary competition. Nonnative buffelgrass, which has a tendency to “out-compete” native plants, has been planted for livestock foraging all throughout South Texas. Also, as buffelgrass and other invasive grasses have encroached the native land of prostrate milkweed, the milkweed species has been dealing with habitat loss and degradation. The milkweed has also been destroyed by other human activities like road construction and increased oil and gas production. According to the USFWS, prostrate milkweed has a low chance of surviving in soils that have been disturbed by large actions like bulldozing and plowing. This is because these types of actions prevent plant regrowth by destroying the plant tubers, which are underground stems used for nutrient storage. Border security enforcement activities and border wall construction on the Lower Rio Grande Wildlife Refuge have also disturbed the prostrate milkweed population. As construction continues to expand, the milkweed is faced with greater danger.

Setting aside a “critical habitat” for prostrate milkweed would specifically protect areas that contain the geographic features essential to conserving the species. Critical habitat areas are protected from federal actions and federal funding that could destroy or harm them. If prostrate milkweed were to be appointed a critical habitat area, the plant would benefit tremendously. Endangered species that are designated critical habitats are twice as likely to be trending toward recovery than those without the designation.

The proposed rule by the Fish and Wildlife Service is available for public comment until April 18, 2022. Within a year, the USFWS will make its final decision on potentially deeming prostrate milkweed as an endangered species and providing the plant with a critical habitat designation. The USFWS is currently seeking comments from other governmental agencies, Native American Tribes, the scientific community, industry, or any other individuals who are interested in this new proposed rule to protect prostrate milkweed. You can leave a comment by clicking here. 

It is critical that we take action now to protect not only the plant but the ecosystems it belongs to. By supporting prostrate milkweed, we can save the butterflies.

Sources: CBS News, Center for Biological Diversity, Federal Register, International Business Times, Nature World News, Texas Tribune, U.S. Fish and Wildlife Service