Scientists can use DNA left in the environment to survey biodiversity in ecosystems. It is a useful tool in remote areas, where it is hard to watch or capture species.

Scientists can use DNA left in the environment to survey biodiversity in ecosystems. It is a useful tool in remote areas, where it is hard to watch or capture species.
A new report by conservation groups finds that many fish species in the Mekong River are threatened with extinction, but there is hope.