US butterflies have dropped by 22% in two decades, says the survey

Butterfly populations in the United States shrink more than one fifth within two decades, according to a new study.

The number fell 22% between 2000 and 2020, according to research at Binghamton University in New York.

One third of the species watched a serious decline, with some, such as Julia captain, lost more than 90% of their populations.

However, researchers say butterflies may be able to recover if urgent conservation measures are taken.

The study published in Science Magazine Measured “abundance” of the butterfly – the number of people of a species in a particular area. He analyzes 12.6 million butterflies from 76,000 studies in 35 monitoring programs.

This includes data from civil scientific programs such as the number of July Fourth at the North America butterflies Association.

Using statistical models, they evaluated the trends in the population for 342 species.

The results show that 33% are in a significant decrease, many of which show extreme losses – 107 species have decreased by more than 50%.

“While the results brought into line with global trends, the vision of the degree of declines on such a large spatial scale was sobering,” says Prof. Eliza Grerei, an associate professor of biological sciences at Binghamton University.

Some of the most affected species include Florida White, Hermes Copper, Tailed Orange, Mitchell's Satyr and West Virginia White, all of which have been abundant by more than 98% in the United States.

The lady on the west coast, once a simple butterfly in the backyard, decreases by 80%, raising the alarm as even this highly adaptive appearance fights.

“This is alarming because it suggests that even ordinary butterflies are not safe,” said Prof. Grerei.

Habitats loss, pesticides and climate change are key causes of this decline, according to researchers.

Butterflies are decisive pollinators supporting plants and crops. Experts say their decline can disrupt food and entire ecosystems.

They also serve as indicators of environmental health – when the number of butterflies falls, it signals problems for other species.

The species decrease most in the United States to the southwest, one of the hottest and most dry regions, the researchers say. They believe that drought can contribute to these losses.

“The drought is a double threat – it damages the butterflies directly and also affects their plants for food and hosts,” explained Prof. Grerei.

The results can help to achieve important protection efforts, such as prioritizing species for the International Union for Nature Protection (IUCN), the red list of endangered species and the protection of endangered species.

Despite the decline, there is hope for recovery.

“Butterflies can recover quickly because they have time for a short generation. Small actions such as planting wild flowers, reducing the use of pesticides, or even leaving part of the backyard, they cannot significantly improve their chances,” said Prof. Grarei.

She also emphasized the need for government actions.

“Insects are basic for the life of the earth and we need actions to protect and policies that support insects.”