Mass extinctions were followed by periods of low diversity in which certain new species dominated wide regions of the supercontinent Pangaea, reports a study published in Nature Communications this week. The findings indicate that mass extinctions may have predictable consequences and provide insights into how biological communities may be expected to change in the future as a result of current high extinction rates.
Mass extinctions are thought to produce ‘disaster faunas’, communities dominated by a small number of widespread species. However, studies to test this theory have been rare and limited in scope, such as being focused on small regions. To address these issues, David Button and colleagues assess long-term changes in biodiversity in the supercontinent Pangaea. They analyse changes in nearly 900 animal species between approximately 260 million and 175 million years ago (spanning the late Permian to Early Jurassic). This period witnessed two mass extinctions and the origins of dinosaurs and modern vertebrates.
Their results show that, after both mass extinctions, biological communities not only lost a large number of species, but also became dominated by widespread, newly-evolving species, leading to low diversity across the globe. These common patterns suggest that mass extinctions have predictable influences on animal distributions and may have the potential to guide modern conservation efforts, the authors conclude.