Species living on land make up 85 percent to 95 percent of all biodiversity on Earth today. This is especially impressive when we consider that the continents cover only 30 percent of our planet’s surface area. And that most land species are descendants of a small number of pioneering groups that invaded the land about 400m years…
Species living on land make up 85 percent to 95 percent of all biodiversity on Earth today. This is especially impressive when we consider that the continents cover only 30 percent of our planet’s surface area. And that most land species are descendants of a small number of pioneering groups that invaded the land about 400m years ago.
Surprisingly, though, scientists strongly disagree about when land biodiversity reached modern levels. Is what we see today typical of the last several tens, or even hundreds, of millions of years? Or has diversity been increasing exponentially, with substantially more species alive today than ever before?
In a new paper in Nature Ecology & Evolution, my co-authors and I examined how the diversity of land vertebrate species living in “local” ecosystems (also known “ecological communities”) changed over the last 375m years. We analysed nearly 30,000 fossil sites that have produced fossils of tetrapods, land vertebrate animals, such as mammals, birds, reptiles (including dinosaurs) and amphibians. Counting species within individual fossil sites allowed us to estimate the diversity in ancient ecological communities.
Our results show that the rich levels of biodiversity on land seen across the globe today are not a recent phenomenon. Diversity within tetrapod ecosystems has been similar for at least the last 60m years, since soon after the extinction of the dinosaurs.
