(CN) – Monarch butterflies from east of the Rocky Mountains received a reprieve on Wednesday as a recent survey count showed their population increased by more than 144 percent, a dramatic increase from previous years.
News of the uptick arrived shortly after it was reported that the western population of the monarch butterfly had dropped to an all-time low.
Since the 1990s, populations of the iconic orange and black butterfly have been on a downward spiral mainly due to habitat destruction and commercial use of pesticides, according to the Center for Biological Diversity.
The butterflies migrate to warmer climates during the winter months and most North American monarchs make their way to Oyamel fir forests on 12 mountaintops in central Mexico, according to researchers.
The annual count conducted by the World Wildlife Fund Mexico found a much more robust population waiting for them, as the large cluster of orange on trees signified the butterflies.
As recently as 25 years ago, monarch butterflies covered about 50 acres of forest during the winter season and in 2014 that dropped to about 2 acres.
This most recent count was about 15 acres of occupied forest, up from 6 acres the previous winter. Conservative estimates show that monarch butterflies have lost an estimated 165 million acres of breeding habitat in the United States due to herbicide spraying that has killed off milkweed that are eaten by caterpillars. Pesticides sprayed on corn and soybean crops are just one of many threats to the butterfly.
A more favorable spring and summer increased the amount of breeding grounds that explained the most uptick in the eastern butterfly’s population, but researchers said more are needed. Environmental advocacy groups have petitioned the federal government to give the monarch butterfly protection status under the Endangered Species Act and their petition is under review by the U.S. Fish and Wildlife Service who expect to make a final decision later this year.
West of the Rocky Mountains, monarch butterflies have seen a substantial drop in their numbers, reaching a record low of about 30,000 last year, down from 1.2 million just two decades ago.
Estimates show that if these trends continue, the western population has a 63 percent chance of extinction in 20 years and more than an 80 percent chance in the next 50 years.
Conservation advocates are pushing for monarch butterfly habitat protection near the Pacific Coast and working with farmers and land managers planting in the Central Valley in California to keep the butterfly’s breeding grounds thriving.
There are some actions people can take to help – such as reducing pesticide use and planting early blooming flowers and milkweed to bolster breeding and migratory space.