Humans have completely destabilized land animal diversity

Or has diversity been increasing exponentially, with substantially more species alive today than ever before?Visit Hard Fork.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. Instead, it’s likely that the way species interact – for example, by competing for resources such as space and food – tends to limit the number of species that can be packed into local ecosystems.That doesn’t mean that local diversity in tetrapods hasn’t increased over the course of the last 375m years. But after this large rise, local tetrapod diversity didn’t increase over the next 60m years.The competing models of animal diversification make clear predictions about how diversity at the local scale should change over geological time, with either long-term stability or continual increases. But previous work by my research group on continental-scale land vertebrate diversity in the Mesozoic and early Cenozoic eras (around 250m to 47m years ago) suggests that, over long timescales, species counts within continents show a similar pattern to those at the local scale.