Good news is always welcome. And the good news is that the U.S. Fish and Wildlife Service listed the prostrate milkweed as endangered under the Endangered Species Act. Only 24 populations of it survive in south Texas and northern Mexico, where they are a food source for pollinators such as bees and monarch butterflies. The listing also designates 661 acres in Starr and Zapata Counties in Texas as critical habitats for the prostrate milkweed.
Texas is key for monarch butterflies who spend their entire lives migrating from Canada and the U.S. to Mexico. Texas is between the main breeding grounds in the north and the wintering areas in Mexico. Monarchs travel through Mexico in the fall and spring. The milkweed is the only plant where monarch butterflies lay their eggs and caterpillars feed. As they move through Texas, they lay eggs on milkweeds, which repopulate new generations of monarchs.
The prostrate milkweeds produce enough nectar that pollinating insects that travel far can fly farther and pollinate other distant milkweed populations. However, the numbers and densities of the prostrate milkweed have declined. Only 24 populations of the prostrate milkweed remain in Starr and Zapata counties in Texas and Tamaulipas and eastern Nuevo León in Mexico. Nineteen of those populations are in low condition, while the remaining five are in moderate condition. None of them are in high condition.
Ninety percent of the monarch population has been lost in the last 25 years. The journey for monarchs is more challenging and less successful because of habitat loss, illegal logging, pesticides, livestock farming, and deforestation. Border wall construction is also a threat to the monarch and milkweed populations. Recent border wall construction degraded 20 acres of monarch habitat. All milkweed populations in the U.S. are within nine miles of the border.
“Protecting prostrate milkweed is a big deal for the monarch butterflies who lay their eggs on these plants as they fly through Texas after spending the winter in Mexico,” said Tierra Curry, a senior scientist at the Center for Biological Diversity, in a statement. “For the sake of the milkweed and all the pollinators who rely on it, it’s a relief that this important native plant finally has the safeguards of the Endangered Species Act.”
The Importance of the Endangered Species Act
Enacted in 1973 as a response to dwindling animal and plant species, the Endangered Species Act celebrates its 50th anniversary this year. The ESA saved 99 percent of listed species from extinction. The bald eagle and peregrine falcons are good examples. By the mid-20th century, the bald eagle, the national symbol, faced extinction in most of its range. Habitat destruction and degradation, illegal shooting, and contamination of their food source from the insecticide Dichlorodiphenyltrichloroethane (DDT) threatened the bald eagle. The federal government removed the bald eagle in 2007 from the endangered species list.
In the 1940s, only around 3.875 nesting pairs of peregrine falcons were left. Their population dramatically decreased from the 1940s to the 1960s, driven mainly by synthetic pesticide use. There were only 324 nesting pairs left by 1975. The federal government removed the peregrine falcon in 1999 from the list of endangered species.
Photo by Lasclay on Unsplash