Assessing richness differences between blue and green systems by quantifying biodiversity turnover along global gradients

In this project, we will analyze how biodiversity is structured along geographical and environmental gradients in three systems (terrestrial, freshwater, marine). We ask to what degree the three systems differ with regard to (1) species turnover (replacement vs. nestedness), (2) niche packing and niche overlap, and (3) accessible gradient lengths within systems. We further ask (4) to what degree these rates and patterns vary along the analyzed gradients within the three systems. The resulting knowledge will explain to what degree species richness is accumulated similarly or differently along these gradients and within the three systems, and where specific accumulation boosts or gaps exist. This will allow us to interpret the observed differences in the structuring of the global biodiversity between the three systems in the light of evolutionary and macroecological drivers.