A new study has revealed a significant decline in the population of monarch butterflies around the US. In the past two decades, the number of monarchs spending winter in the forests of Mexico has decreased by more than 80%.

However, according to Mark Ferguson, a biologist for the Vermont Fish & Wildlife Department, Vermont may play an important role in the continued efforts at monarch conservation.

According to him, Vermont's meadows and old fields provide habitat for milkweed, which is a critical food source for monarchs. The old fields and meadows in Vermont provide a home to milkweeds, while the adults of this species lay eggs on milkweeds, the caterpillars survive on those plants.

Most eastern monarchs overwinter at a single site in the mountains of central Mexico. Ferguson said monarchs need to reproduce several times during their north-bound migration, and require milkweed at each of these sites.

However, he also mentioned there has been reduction in the abundance of milkweed with the increasing levels of herbicide use in large-scale agriculture in the Midwest.

Insecticides referred to as neonicotinoids are used on agricultural crops, and are also used in concentrated doses on home gardens, lawns, and ornamental trees. They might threaten monarch conservation.

Ferguson has recommended that people should limit the use of insecticides and herbicides in order to allow Vermont's residential yards, meadows, old fields and pastures to support monarchs and their habitat.