Unraveling drivers of species diversification – an integrative deep-time approach on continental aquatic biota

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Understanding processes and settings controlling species diversity and diversification is an ongoing subject of intense research. What enables or limits maximum species numbers? What factors drive speciation and extinction? On what spatial and temporal scales do these drivers act? Studies investigating these questions have yielded quite diverging answers. A main limitation to inferring drivers of diversification has been the fixed temporal scope applied so far. Assuming that the same processes operate uniformly across different time scales might severely hamper our ability to understand the factors controlling diversification. Also, it is of paramount importance to address the impact and interplay of multiple (biotic and abiotic) factors sustaining biodiversity and driving turnover.The goal of this project is to unravel (combinations of) drivers of diversification and at what spatiotemporal scales they are relevant. We will use an extensive dataset of fossil freshwater gastropods from North America and Europe covering the past 100 myr. Potential drivers include both abiotic (climate, orbital cyclicity and tectonic complexity) and biotic factors (competition intensity, predation pressure and passive dispersal potential). Temporal impacts are measured at a variety of spatial, habitat and life style levels. A novel “floating windows” approach will be developed that allows assessing covariation between diversification rates and potential drivers across variable time frames. By comparing impact of (sets of) drivers between Europe and North America through time we also aim to distinguish between global and regional drivers. The analytical pipeline will be combined in a comprehensive open-source R package.We expect that our contribution featuring novel analytical techniques in a deep-time and transcontinental approach will place a new and integrated perspective on the study of diversification dynamics. It will address the importance of the variable temporal and spatial scales at which drivers act on diversification processes. The anticipated results will help to identify and quantify tipping points in Earth history on various scales. The project will constitute an important baseline for future assessments of the impact of contemporary (and expected future) global change scenarios on the current biodiversity crisis.