Marine communities differ in species richness at global and provincial scales. That the diversity declines from equatorial to polar regions (latitudinal diversity gradient, LDG) is the most pervasive pattern in modern ecosystem. Although recognized for more than two centuries, the underlying mechanisms responsible for elevated low-latitude richness are still unclear. Deriving LDG patterns in deep time can help us understand how biodiversity is generated and maintained, as well as how species composition and biodiversity responded to major extinction events. Here we use fossil occurrences data documented in the Paleobiology, Geobiodiversity, and PhytoPal databases, to derive LDG patterns from the Cambrian to the Silurian among different geographic regions and trophic communities to elucidate ecological and environmental drivers of biogeographic changes over the early Paleozoic. To further understand the functional consequences of the changes in diversity and faunal composition along latitudinal gradient, we classified taxa into different functional groups based on their functional traits. By quantifying functional traits of all taxa, we assess the relationship between functional and taxonomic diversities among biogeographic regions. By dissecting diversity dynamics along ecological and latitudinal gradients, we aim to find key controls on variation in geographic distribution of biodiversity in early Paleozoic marine ecosystem. We find that there is no strikingly LDG trend in the early Paleozoic. Regional differences of faunal composition and biodiversity in non-tropics are strongly controlled by sampling bias, and long-term variation in climate and plate tectonics pose strong influences on biogeographic differences in both taxonomic and functional diversities.
Latitudinal gradient control on early Paleozoic biodiversity and ecosystem functioning