For anyone who still doubts that amphibian populations are declining worldwide, Jeff E. Houlahan has a message: Give up.
The ecologist at the University of Ottawa worked with an international team to crunch the biggest data set yet assembled for amphibian populations. The team collected information from 200 scientists who've examined 936 populations in 37 countries—most in Europe and North America.
Individual species and places vary, but "at a global scale, amphibians have declined over the past several decades," Houlahan and four coauthors announce in the April 13 Nature.
"We wanted to just pile the data as high as we could and see if we have declines," Houlahan says.