While in the past fluctuations in Monarch populations could be explained by factors such as a cold winter, the evidence is now clear that there are human factors putting downward pressure on monarch populations.
(Beyond Pesticides) Monarch butterflies are in the midst of a staggering decades-long population decline that has rapidly accelerated since 2005, research published by an international team of scientists and the University of Florida last month indicates. According to data meticulously collected by researchers, monarchs making their way to central Florida after emerging from their breeding grounds in Mexico have declined by 80% over the last decade and a half. This is roughly the same time frame at which beekeepers began to see precipitous declines in managed honey bee colonies. Researchers point to industrial development and increasing pesticide use as factors that have accelerated the decline of this iconic species.
“A broad pattern is that 95 percent of corn and soybean products grown in the U.S. are Roundup Ready crops that resist glyphosate,” said study coauthor Earnest Williams, PhD, of New York’s Hamilton College in a press release. “That has a national impact. What’s really needed are patches of native vegetation and nectar sources without pesticides. It’s not just for monarchs but all pollinators.”
I followed three Monarchs in my garden this morning with the camera. Their food source, the Wild Cotton weed or Milk wood, is in decline in my gardens despite me trying to encourage it.
The Monarch was introduced to Australia soon after the Europeans arrived. There seems to be a different view on the Monarchs arrival in Australia. One account I remember reading suggesting it flew here from Brazil, another that arrived with the new settlers.