The distribution of global biodiversity (Clinton Jenkins link), a Rufous-necked Hornbill a keystone seed-disperser, planting the rainforests of the future  (photo, Mitash Biswas).

The origin and future of biodiversity

The most remarkable thing about life on Earth is its diversity. Although biodiversity estimates remain highly uncertain, recent studies suggest that Earth is home to more than 8 million Eukaryotic species and innumerable microscopic organisms. Our research team seeks to understand the processes through which this biodiversity has been generated, why so much biodiversity is concentrated in a few special places and how human driven changes in biodiversity are impacting the ecological processes that underpin the functioning of the biosphere and ultimately human society.

To address this, our research takes a macroscopic perspective, analysing the distribution and dynamics of biodiversity across large spatial, taxonomic and temporal scales. There has never been a better or more exciting time to address these questions. Centuries of collection efforts by naturalists, advances in genetic sequencing and remote sensing, and the growing trends of global citizen science initiatives, are now enabling scientists to map the distribution of species at higher resolutions, providing detailed information on where each species lives on the planet, its ecological niche and its phylogenetic relationships. By contributing to and combining these datasets, our group is developing new analytical approaches to model how ecological communities have assembled over time (Pigot and Etienne 2015), and understand how ecological interactions (Pigot and Tobias 2013), the environment (Pigot et al 2010, Pigot et al 2016) and evolutionary history (Pigot et al 2012, Pigot et al 2018) shape the distribution of life. For example, our recent work provides new evidence that competition can limit the geographic overlap between between species of birds for millions of years after speciation, but that such constraints are relaxed in highly productive ecosystems, providing one explanation for the higher diversity of species seen in the tropics (Pigot et al 2016, Pigot et al 2018). Using global databases of species niches and morphological traits for birds, we have found that species exploiting similar environments but on different continents (e.g. frugivorous  Toucans in the New World and Hornbills in the Old world), have converged in their morphology, suggesting that evolution and the assembly of communities is highly repeatable and deterministic (Pigot et al 2020).   

​Human activities are driving enormous and rapid changes to the planetary environment, fundamentally altering the distribution of life on Earth (Pigot et al 2018, Redding et al 2019, Trisos et al 2020) and drastically elevating rates of species extinction. Our research team is  concerned by these changes and motivated to improve our understanding and predicting 1) of  how biodiversity is changing and will continue to change over the coming decades and 2) how these changes are impacting the ecological processes that underpin the functioning of Earths ecosystems. Most research of the ecological impacts of biodiversity is based on highly controlled experiments conducted over small spatial scales (a few metres). We are addressing this by developing and applying large-scale datasets on the functional traits of birds (Pigot et al 2020) and other vertebrates to model their responses to environmental change and their effects on key ecological processes (e.g. seed dispersal) (Pigot et al 2016a, Pigot et al 2016b). By applying the approaches and thinking we have developed for dynamically modelling the historical assembly of communities we are looking for ways to accurately forecast how ecological communities will change over the coming decades, to identify where and when tipping points of biodiversity loss are at risk of being crossed, and how both biodiversity and human society can avoid these (Trisos et al 2020, Lovell et al 2021).         ​     ​