A decade-long global effort to save Earth's disappearing species and declining ecosystems has mostly stumbled, with fragile habitats like coral reefs and tropical forests in more trouble than ever, researchers said in a report Tuesday. In 2010, more than 150 countries agreed to goals to protect nature, but the new United Nations scorecard found that the world has largely failed to meet 20 different targets to safeguard species and ecosystems. If this were a school and these were tests, the world has flunked, said Elizabeth Maruma Mrema, executive secretary of the U.N. Convention on Biological Diversity, which released the report.