Info supplied by Modern Farmer
Monarch butterflies, which are major wildflower pollinators, have showed some disturbing downward trends in their population, with one study from 2016 suggesting a bonkers 80 percent decline over the past decade. New data indicates that monarch numbers, at least at an important overwintering spot in Mexico, are continuing to decline.
Every winter, monarch butterflies in North America migrate south in two major groups: those west of the Rocky Mountains spend their winters in the lower half of California, while those east of the Rockies head down to the Monarch Butterfly Biosphere Reserve in central Mexico, just north of Mexico City. Up to a billion butterflies descend on this reserve every year—so many that the only way to count them is by simply counting the acreage dominated by the insects.
The estimated number of butterflies in the reserve varies every year, from insane highs of 44 acres (in 1996-’97), down to extreme lows of 1.66 acres, as was the case in 2013-’14. But despite occasionally jumping in population (and increased activism lately), the insect’s population has been on an overall downward trend since the 90s. This year, the monarchs covered only 6.12 acres—a nearly 15 percent reduction from last year.