The monarch butterfly may be a step closer to getting Endangered Species Act protection.

 In response to a petition by the Center for Biological Diversity, Center for Food Safety, the U.S. Fish and Wildlife Service announced Endangered Species Act protection may be necessary for monarchs, which have experienced a shocking 90 percent decline in population over the past 20 years.

The agency now plans to conduct a one-year review of the monarchs in order to determine if they will be given the crucial protection.

"We are extremely pleased that the federal agency in charge of protecting our nation's wildlife has recognized the dire situation of the monarch," said Sarina Jepsen, the Xerces Society's endangered species director. "Protection as a threatened species will enable extensive monarch habitat recovery on both public and private lands."

The species' drastic decline is believed to be largely linked to the planting of genetically modified crops in the Midwest. The crops are modified to be resistant to Monsanto's Roundup herbicide which kills milkweed, monarch caterpillars' only food source. Roundup has nearly wiped out Midwestern milkweed plants, and it has been estimated monarchs have lost about 165 million acres of breeding ground over the past 20 years.

In the mid-1990s there were about 1 billion monarch butterflies, that population had dropped to 35 million last winter, which is the lowest numbers ever recorded. The decline is also believed to be influenced by global climate change, urban sprawl, and logging in their forest winter grounds located in Mexico.

"The Endangered Species Act is the most powerful tool available to save North America's monarchs, so I'm really happy that these amazing butterflies are a step closer to the protection they so desperately need," said Tierra Curry, a senior scientist at the Center for Biological Diversity.

The overwintering population is predicted to be up this year due to favorable spring and summer weather, but will still be nowhere near its historical size.

"The Fish and Wildlife Service must next issue a '12-month finding' on the monarch petition that will propose protection under the Endangered Species Act, reject protection under the Act or add the butterfly to the candidate waiting list for protection," the Center for Biological Diversity stated.