The U.S. Geological Survey (USGS) has estimated 6 hectares are required for monarchs to stay afloat in the long run. “Current monarch numbers are not sustainable,” says ecologist Karen Oberhauser of the University of Wisconsin, Madison.
The U.S. Geological Survey (USGS) has estimated 6 hectares are required for monarchs to stay afloat in the long run. “Current monarch numbers are not sustainable,” says ecologist Karen Oberhauser of the University of Wisconsin, Madison.