http://colombiareports.co/one-species-rule-giant-crocodile-fossil-discovered-northern-colombia/
June 4, 2014
Habitat loss on breeding grounds cause of monarch decline, study finds
2 hours ago
Habitat loss on breeding grounds in the United States not on wintering grounds in Mexico is the main cause of recent and projected population declines of migratory monarch butterflies in eastern North America, according to new research from the University of Guelph.
The groundbreaking study was published today in the Journal of Animal Ecology.
"Our work provides the first evidence that monarch butterfly numbers in eastern North America are most sensitive to changes in the availability of milkweed on breeding grounds, particularly in the Corn Belt region of the United States," said Ryan Norris, a professor in Guelph's Department of Integrative Biology.
He conducted the study with lead author and current Guelph post-doc Tyler Flockhart, as well as scientists from the Commonwealth Scientific and Industrial Research Organisation (Australia's national science agency).
These results contradict the long-held belief that monarch butterflies are most vulnerable to disturbances on wintering grounds in Mexico. They also confirm suspicions that recent declines have actually been driven by breeding events.
During the winter months, monarch butterflies congregate in a small area at high densities in Mexico. Scientists thought factors on those wintering grounds, such as climate change or deforestation, were the greatest threat to the population.
More:
http://phys.org/news/2014-06-habitat-loss-grounds-monarch-decline.html#jCp