Monarch Butterflies Rebound
Monarch butterflies have made a big comeback in their wintering grounds in Mexico, after suffering serious declines, experts said Friday.
The area covered by the orange-and-black insects in the mountains west of Mexico City this season was more than three and a half times greater than last winter. The butterflies clump so densely in the pine and fir forests they are counted by the area they cover rather than by individual insects.
The number of monarchs making the 3,400-mile (5,500-kilometre) migration from the United States and Canada declined steadily in recent years before recovering in 2014. This winter was even better.
This December, the butterflies covered 10 acres (about 4 hectares), compared to 2.8 acres (1.13 hectares) in 2014 and a record low of 1.66 acres (0.67 hectares) in 2013.
While that’s positive, the monarchs still face problems: The butterflies covered as much as 44 acres (18 hectares) 20 years ago.
The United States is working to reintroduce milkweed, a plant key to the butterflies’ migration, on about 1,160 square miles (3 million hectares) within five years, both by planting and by designating pesticide-free areas. Milkweed is the plant the butterflies feed and lay their eggs on, but it has been attacked by herbicide use and loss of open land in the United States.
In Mexico, meanwhile, illegal logging has remained a problem. It more than tripled in the monarch butterflies’ wintering grounds in 2014, reversing several years of steady improvements. Illegal logging had fallen to almost zero in 2012.
Authorities said the reserve’s buffer area lost more than 22 acres (9 hectares) in 2015 due to illegal logging in one area, but said the tree cutting was detected and several arrests were made.
The forest canopy acts as a blanket against the cold for butterflies forming huge clumps on branches during their winter stay in Mexico.
Bees are vanishing: U.N. report
Many species of wild bees, butterflies and other insects that pollinate plants are shrinking toward extinction, and the world needs to do something about it before our food supply suffers, a new United Nations scientific mega-report warns.
The 20,000 or so species of pollinators are key to growing fruits, vegetables and cash crops. Yet two out of five species of invertebrate pollinators, such as bees and butterflies, are on the path toward extinction, said the first-of-its-kind report. Pollinators with backbones, such as hummingbirds and bats, are only slightly better off, with 1 in 6 species facing extinction.
“We are in a period of decline and there are going to be increasing consequences,” said report lead author Simon Potts, director of the Centre for Agri-Environmental Research at the University of Reading in England.
The trouble is the report can’t point to a single villain. Among the culprits — the way farming has changed so there’s not enough diversity and wild flowers for pollinators to use as food; pesticide use, habitat loss to cities; disease, parasites and pathogens; and global warming.
The report is the result of more than two years of work by scientists across the globe who got together under several different U.N. agencies to come up with an assessment of Earth’s biodiversity, starting with the pollinators.
“The variety and multiplicity of threats to pollinators and pollination generate risks to people and livelihoods,” the report stated.
“These risks are largely driven by changes in land cover and agricultural management systems, including pesticide use.”