Increase in marine provinciality over the last 250 million years governed more by climate change than plate tectonics

Abstract

Amidst long-term fluctuations of the abiotic environment, the degree to which life organizes into distinct biogeographic provinces (provinciality) can reveal the fundamental drivers of global biodiversity. Our understanding of present-day biogeography implies that changes in the distribution of continents across climatic zones have predictable effects on habitat distribution, dispersal barriers and the evolution of provinciality. To assess marine provinciality through the Phanerozoic, here we (a) simulate provinces based on palaeogeographic reconstructions and global climate models and (b) contrast them with empirically derived provinces that we define using network analysis of fossil occurrences. Simulated and empirical patterns match reasonably well and consistently suggest a greater than 15% increase in provinciality since the Mesozoic era. Although both factors played a role, the simulations imply that the effect of the latitudinal temperature gradient has been twice as important in determining marine provinciality as continental configuration.

Global diversity dynamics in the fossil record are regionally heterogeneous

“…As Circumtethys is an extremely large region compared to the others, we subdivide it into eastern and western subdomains. While the extent of spatial regions reflects a compromise between biogeographic discretion and data availability and can theoretically be arbitrary, we note that most of our regions share a degree of correspondence with bioregions for the Permo-Triassic predicted from abiotic drivers of marine provinciality 72 , suggesting that they are biologically realistic to a certain extent. The major exception to this is our east-west division of Tethys compared to the north-south divide recovered by Kocsis et al 32 , 33 , 72 as this was a compromise between biogeographic realism and data availability through time.…”

Post-extinction recovery of the Phanerozoic oceans and biodiversity hotspots

“…The model considers a single distance-decay function for the spatial turnover of taxonomic composition. However, the degree of provinciality (that is, the partitioning of life into distinct biogeographical units) varies in space and time as a result of environmental gradients 62 and plate tectonics 63 . In fact, the increase in provinciality has been invoked as the main driver of the increase in global diversity, especially in the Late Cretaceous and Cenozoic 22 , 62 , 63 .…”

“…This is a deficiency of the model. Unfortunately, information on the extent to which marine provinciality has varied in space and time throughout the Phanerozoic is limited 61 , 62 , and there is no simple (mechanistic) way to implement different distance-decay functions of taxonomic similarity in the model. There is a clear difference between longitudinal and latitudinal distance, the latter being a more significant source of taxonomic turnover 62 .…”

“…Unfortunately, information on the extent to which marine provinciality has varied in space and time throughout the Phanerozoic is limited 61 , 62 , and there is no simple (mechanistic) way to implement different distance-decay functions of taxonomic similarity in the model. There is a clear difference between longitudinal and latitudinal distance, the latter being a more significant source of taxonomic turnover 62 . This effect would add to the observation that tropical diversity hotspots became more prominent towards the end of the Phanerozoic, offering two complementary explanations for the increase in diversity in the Mesozoic: (1) favourable conditions for the development of diversity hotspots and (2) a higher degree of provinciality.…”

“…is a clear difference between longitudinal and latitudinal distance, the latter being a more significant source of taxonomic turnover 62 . This effect would add to the observation that tropical diversity hotspots became more prominent towards the end of the Phanerozoic, offering two complementary explanations for the increase in diversity in the Mesozoic: (1) favourable conditions for the development of diversity hotspots and (2) a higher degree of provinciality.…”