Biotic homogenization: a few winners replacing many losers in the next mass extinction.

Human activities are not random in their negative and positive impacts on biotas. Emerging evidence shows that most species are declining as a result of human activities ('losers') and are being replaced by a much smaller number of expanding species that thrive in human-altered environments ('winners'). The result will be a more homogenized biosphere with lower diversity at regional and global scales. Recent data also indicate that the many losers and few winners tend to be non-randomly distributed among higher taxa and ecological groups, enhancing homogenization.