What are the Biotic interchanges?
We are currently at a peak of Earth's biological diversity, despite recent extinctions caused by the human activities that define the Anthropocene. The Cenozoic, the current geological era, began about 66 million years ago with catastrophic events such as a large asteroid impact or major volcanic eruptions at global level, all of which were followed by significant tectonic movements, mountain liftings, and climatic oscillations. During this era, after an initial big mass extinction, many biological groups diversified rapidly, resulting in drastic changes in the composition of ecological communities.
An important factor that shaped the current distribution of global biodiversity was biotic exchanges: movements of species between different biotas. The high tectonic activity of the Cenozoic caused a reorganization of the planet's land masses, which on the one hand continued the isolation of some biotas, and on the other hand facilitated the exchange of species between biotas with independent evolutionary histories.
Why BI are important to society?
The study of biotic interchanges led to major breakthroughs in our understanding of evolution, paleontology and geography. For example, A. R. Wallace’s observation of admixtures between distinct faunas across Wallace's Line gave rise to the field of global biogeography and informed the concept of natural selection. Through the study of extinct mammals across North and South America, Simpson realised the magnitude of historical intercontinental dispersals, breaking new ground in our understanding of the evolution and ecology of extant (and extinct) faunas in the world. The study of biotic interchanges continues to have the potential to make important advances in knowledge; with an ever-increasing rate of human-mediated invasions, the study of biotic interchanges could also hold key insights for the management and conservation of biota into the future.
Despite the importance of biotic interchanges for understanding the assembly of extant biological communities, macroecological and macroevolutionary studies on biotic interchanges remain scarce.
Objectives of the project
Extensive data on evolutionary relationships and distribution of tetrapod species, through comprehensively-sampled fossil-calibrated phylogenies and big geographic distribution databases curated by experts and conservation organisations have recently been available. Paleoclimatic and tectonic reconstructions at global level have been made available as well. The methods to reconstruct ancestral biogeography, although still with lots of scope to improvement, have also reached some stability and curation in the last decade. Therefore, there is currently a unique and unprecedented opportunity to understand better the magnitude and importance of historical and contemporary biotic interchanges to explain the ecological assembly of current terrestrial vertebrate communities and how this affected their evolution and diversification.
