Mongabay: The world's species are in worse trouble than widely-assumed, according to a new paper in the Proceedings of the National Academy of Sciences (PNAS), which reevaluates how scientists estimate extinction rates. The new model takes into account the impact of forest fragmentation on extinction rates for the first time, filling in a gap in past estimates. Much of the world's tropical forests, which house the bulk of the world's species, have been whittled down to fragments: small forest islands that...