Impact of the Late Triassic mass extinction on functional diversity and composition of marine ecosystems

Abstract

Mass extinctions have profoundly influenced the history of life, not only through the death of species but also through changes in ecosystem function and structure. Importantly, these events allow us the opportunity to study ecological dynamics under levels of environmental stress for which there are no recent analogues. Here, we examine the impact and selectivity of the Late Triassic mass extinction event on the functional diversity and functional composition of the global marine ecosystem, and test whether post-extinction communities in the Early Jurassic represent a regime shift away from pre-extinction communities in the Late Triassic. Our analyses show that, despite severe taxonomic losses, there is no unequivocal loss of global functional diversity associated with the extinction. Even though no functional groups were lost, the extinction event was, however, highly selective against some modes of life, in particular sessile suspension feeders. Although taxa with heavily calcified skeletons suffered higher extinction than other taxa, lightly calcified taxa also appear to have been selected against. The extinction appears to have invigorated the already ongoing faunal turnover associated with the Mesozoic Marine Revolution. The ecological effects of the Late Triassic mass extinction were preferentially felt in the tropical latitudes, especially amongst reefs, and it took until the Middle Jurassic for reef ecosystems to fully recover to pre-extinction levels.

Stratigraphic and environmental control on marine benthic community change through the early Toarcian extinction event (Iberian Range, Spain)

“…Results from our local study mirror those from a global analysis of early Jurassic marine organisms, which found that the early Toarcian event selected against sessile suspension feeders (Dunhill et al 2018a). Similar results have been found for other Mesozoic warming-related extinction events, such as the Late Permian (e.g., Rhodes andThayer 1991, Erwin et al 2002) and the Late Triassic mass extinctions (Dunhill et al 2018a(Dunhill et al , 2018b. In particular, the global scale impact of the early Toarcian event was extraordinarily important for the articulate brachiopods: two major orders, Spiriferinida and Athyridida, and about 67% of the genera belonging to the order Rhynchonellida disappeared (Vörös 2002;Vörös et al 2016;Manceñido 2000).…”

Nature and timing of biotic recovery in Antarctic benthic marine ecosystems following the Cretaceous–Palaeogene mass extinction

“…This is consistent with the hypothesis that global functional diversity is generally retained after mass extinction events, despite severe taxonomic losses (Dunhill et al . ). There is little evidence for detritus‐based benthos (deposit feeders and bottom dwelling predators) preferentially surviving the K–Pg extinction in Antarctica or proliferating in its immediate aftermath to the detriment of suspension feeders.…”

Addressing priority questions of conservation science with palaeontological data

“…Improved constraints on the patterns that signal early warning of ecosystem collapse is thus an obvious route to address this question. Of course, a disconnect will remain between the modern anthropocentric view of ecosystem services and the palaeo perspectives focusing on functional diversity [37,38] and productivity [39]. This question, ranking in the top five by relevance [10], is perhaps the one to which palaeontology can make unique contributions.…”

“…Other elements, such as phylogenetic, functional and ecosystem diversity are also ( partly) accessible in fossil data [70][71][72][73][74]. The most promising endeavour is perhaps functional diversity, for which studies suggest limited loss across mass extinctions among marine invertebrates [37,38] but substantial turnover of functional richness across the Pliocene-Pleistocene boundary for marine megafauna [75].…”