Prodded by donors, the Nature Conservancy, World Wildlife Fund, and other groups are working to create accounting standards (both financial and biological) to measure the success of conservation projects. “There’s no industry standard, no Dow Jones,” said M. A. Sanjayan, a scientist who is leading the conservancy effort. Some $120 billion is spent each year in the United States on protecting ecosystems, but until recently, little work had been done to measure the returns. A recent report involving 150 leading scientists found that half the data needed to assess the health of ecosystems wasn’t scientifically adequate. The Nature Conservancy is piloting a site-by-site auditing program that examines conservation plans, monitors threatened species, and determines whether managers have the resources to carry out their plans. “If this is done right, it will change the whole discussion about conservation,” said Seth Neiman, a conservancy donor, “People will start asking, `What are your results?’”