In a recent paper in the journal Basic and Applied Ecology, Roisin Stanbrook-Buyer, an ecologist at Bethune-Cookman University in Florida, attempted to calculate an exact figure.

佛罗里达州贝塞斯达-库克曼大学的生态学家罗伊辛·斯坦布鲁克-拜耶在《基础与应用生态学》杂志最近发表的一篇论文中试图计算出一个确切的数字。