Monarch Butterfly Numbers Drop to Lowest Level in Recorded History
Scientists say the number of Monarch butterflies wintering in Mexico is now at the lowest level ever since records began in 1993. In their recorded peak in 1995, the butterflies covered more than 44.5 acres of fir and pine forests. This year, researchers were only able to find butterflies across 1.65 acres of land — a mere 56% of last year’s numbers. After three years in steep decline, it’s becoming obvious that this is a long-term trend and not merely a temporary or seasonal dip.
Image © David Slater
The World Wildlife Fund has warned that the Monarch migration is in danger of disappearing altogether. There are a few reasons for the dramatic drop in the butterfly population: unusual weather patterns in recent years have disrupted their ability to reproduce, and more crops are being planted in areas which used to serve as the Monarch’s migratory habitat.
But perhaps the single most devastating threat has been entirely manmade. The widespread use of herbicide-resistant GMO corn and soybeans has resulted in massive losses of the milkweed plant, which has traditionally sprouted up between rows of other crops. Monarchs only lay their eggs on milkweed, and it’s also their primary source of food. When butterflies have to travel longer distances to find the plant, their health suffers and they lay fewer eggs (when they’re able to lay eggs at all).
No one is sure what will happen to the species if it’s no longer able to complete its migration. The migration routes appear to be an inherited trait hardwired into the butterflies; no butterfly survives to make a round-trip journey. Some Monarchs do not migrate far north and are able to survive year-round in warm climates. Some farmers and gardeners in the US and Mexico are fighting back by planting plots of milkweed to provide food for the butterflies, but without widespread intervention, it may simply not be enough to keep the migration alive.
Via The Guardian
Lead image © Plains and Prairie Potholes Landscape Conservation
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