The West Coast Monarch Butterflies are on the edge of extinction after suffering an alarming decrease in its population during the last few decades. According to a new study, the population of these famous butterflies has declined by 97 percent in 30 years.

Scientists say that the decrease of the Monarch Butterflies population is greater than expected. It is mainly a consequence of the loss of their primary food source, the milkweed. As well, they say that their disappearance could be a result of climate change.

Image credit: National Geographic Kids
Image credit: National Geographic Kids

“Like many at-risk species, systematic monitoring of this population began after dramatic declines had already been noticed,” the researchers expressed. “If the population continues to decline at that rate, we will lose migratory monarchs in the western United States over the next several decades”

From 10 million to 300,000 Monarch Butterflies in 3 decades

The population of western Monarch butterflies is declining at a seven perfect rate every year, which is faster than virtually all the population of Easter Monarch butterflies. The latter species is also about to go extinct. The species has faced a 97 percent decline of its population during the last 30 years. To get to this data, scientists have collected available historical records using statistical models to merge data from the 1980s and 1990s with records gathered by scientists during the last two decades.

“In the 1980s, 10 million monarchs spent the winter in coastal California. Today there are barely 300,000,” Cheryl Schultz, a biologist at Washington State University Vancouver who led the study, in a statement. “This study doesn’t just show that there are fewer monarchs now than 35 years ago. It also tells us that, if things stay the same, western monarchs probably won’t be around as we know them in another 35 years.”

In the 1990’s, scientists and people from Western California began noticing that these beautiful and colorful insects were not seen as frequently as before. That is why scientists began tracking western monarch butterflies. Since the Xerces Society’s Western Monarch Thanksgiving Count in 1997, hundreds of volunteers have help scientists to count these butterflies.

Image credit: Modern Farmer
Image credit: Modern Farmer

The disappearance of the monarch butterflies is due to the loss of their food source and due to the increasing urbanization in California. Humans have changed their habitat as many places where the butterflies used to feed and nest are being used for the development the cities and areas for agriculture. Also, climate change plays an important role too.

The study findings were published in the journal Biological Conservation last week. Emma Pelton – endangered species conservation biologist at the Xerces Society for Invertebrate Conservation and co-author of the study – said that this study will help conservationists understand the risks that are faced by the western monarch butterflies and how to protect them. She said that scientists and policy makers were aware of the increasing disappearance of the eastern monarch butterfly population but little did they know before that the western monarch butterfly was facing a greater risk of extinction.

Schultz: ‘Western Monarchs are faring worse than their eastern counterparts’

Unlike the eastern monarch butterflies – which spent the winter in Mexico -, western monarch butterflies stay in California’s coasts during the winter in nests, before they disperse around the west coast for the warmer months. Therefore, losing the nesting areas for the butterflies makes them disappear too. The migration of the western monarch butterflies is also amazing because, after the winter, they go to lay their eggs on milkweed and drink nectar from flowers in Arizona, California, Nevada, Oregon, Washington, Idaho, and Utah. They return to California in the fall.

Schultz says that due to that, they are studying the breeding times and other locations for the Western butterflies to know how to protect these black-and-orange winged insects. For her, there is still hope. She believes that if actions are taken now, it is possible to make out of the 21st century the era when these butterflies return to landscapes.

“The hard part of being a conservation biologist is documenting species declines. The exciting part is figuring out how to help declining species recover” said study co-author Elizabeth Crone, an ecologist at Tufts University. “In the 20th century, we brought bald eagles back from the brink of extinction by limiting use of DDT”

Currently, the U.S. Fish and Wildlife Service is considering adding the monarch butterfly to the list of threatened species under the Endangered Species Act. This agency also helped to fund the research. They are facing a 63 percent chance of extinction in 20 years and an 84 percent chance in 50 years if current trends continue. The monarch butterfly is one of Americas’ most popular and recognizable butterflies. They are a common subject of study for students and scientists internationally.

Source: Smithsonian