Country Life

But most spoken to for this article accepted the findings, while fearing that in the “large-scale reorganization,” most of the losers are rare, endangered, and endemic species, while most of the winners are common, generalist, and invasive species — rats, mosquitoes, water hyacinth and the like. That would explain the central conundrum raised by the findings — that species numbers remain high locally, while collapsing globally. The generalists are taking over — a process the authors of the paper call “homogenization.”

A debate has been brewing among ecologists for a while about the real state of biodiversity at different spatial scales. It is more than two decades since researchers first pointed out that the dramatic global loss of species did not seem to be reflected in some local ecosystems, many of which have more species than in the past. Such places range in size from small oceanic islands to North America, which has many more plant species since the arrival of Europeans.