Pesticide distributions and population declines of California, USA, alpine frogs, Rana muscosa and Rana sierrae. Environ Toxicol Chem. 2011 Mar;30(3):682-91. doi: 10.1002/etc.425. Jan 5 2011
What does this mean?
Although this study did not find a link between the pesticides examined, many other studies have, e.g. this one.