Monarch butterflies now endangered, two steps from extinction

Researchers explain decline, glimmer of hope that might save them

The International Union for Conservation of Nature added the migrating monarch butterfly to its “red list” of threatened species and has now categorized it as endangered.

SAN ANTONIO – The International Union for Conservation of Nature added the migrating monarch butterfly to its “red list” of threatened species and has now categorized it as endangered.

That categorization is just two steps away from extinction.

The endangered migratory monarch butterfly is a subspecies of the monarch butterfly called Danaus plexippus. The migrating monarch makes its trek annually from Mexico and California in the winter to its summer breeding grounds throughout the United States and Canada.

The monarch population however has readily declined by 90% in the past two decades, according to federal scientists.

Dr. Karen Oberhauser, Professor of Entomology at the University of Wisconsin, said one of the main reasons for the decline is that climate change is causing extreme heat, drought and other weather events.

”We can get these extreme years, but on average we’re getting more extreme years,” Oberhauser said.

Oberhauser is also the director of the arboretum and has been studying monarchs for thirty years. She said she is concerned about the extreme heat and drought that several parts of the country are experiencing this year, like here in San Antonio.

She said the weather will impact the butterfly’s food source.

”The nectar plants won’t be producing as much nectar,” Oberhauser said. “Some of the flowers are dried up. In some cases they’re not even around anymore.”

Another reason for the decline she said is mass use of pesticides, which has resulted in habitat loss for monarchs.

For example, she said a lot of milkweed -- the prime food source for monarchs -- used to grow in corn and soybean fields.

”Now farmers can control all weeds in their fields with herbicides because the plants are genetically modified to resist herbicides,” Oberhauser said.

But there is good news, as scientists have used this data to raise a massive amount of awareness.

Twenty three states, including Texas, have committed to preserving the monarch habitat, especially in the past ten years.

Oberhauser said because of this awareness the numbers aren’t on the severe decline like they were twenty years ago.

”There are a lot of people that are making efforts to increase the amount of habitat that’s available to make up for all that habitat that we lost in agricultural fields,” she said. “But we’re kind of holding our own because we’re adding habitat at the same time we’re subtracting habitat. So I think that monarch numbers probably would still be declining if people weren’t doing as much as they’re doing now.”

Oberhauser said it’s important to protect the monarchs, not because our ecosystems will collapse without them, but because they are a flagship indicator of how intact our ecosystems are.

It’s important to remember healthy ecosystems keep humans healthy safe from disease spread and nature decline.

”If things are going badly for monarchs, they’re going badly for a lot of other things,” she said. “So they’re an indicator of how things are going.”

About the Author:

Sarah Acosta is a weekend Good Morning San Antonio anchor and a general assignments reporter at KSAT12. She joined the news team in April 2018 as a morning reporter for GMSA and is a native South Texan.