Summary
Life on Earth has been challenged repeatedly by periods of catastrophic change that shift the structure and function of communities and ecosystems. The consequences of environmental upheaval have traditionally been studied by paleontologists reconstructing the appearance and disappearance of species in the fossil record. That approach has revealed much about extinction as a process, but has left questions unanswered about the properties of species that lead to persistence. Contemporary changes in the abundance of wild plants and animals provide biologists with the opportunity to track and stud
