Current extinction rate in European freshwater gastropods greatly exceeds that of the late Cretaceous mass extinction

Abstract

The Cretaceous–Paleogene mass extinction event 66 million years ago eradicated three quarters of marine and terrestrial species globally. However, previous studies based on vertebrates suggest that freshwater biota were much less affected. Here we assemble a time series of European freshwater gastropod species occurrences and inferred extinction rates covering the past 200 million years. We find that extinction rates increased by more than one order of magnitude during the Cretaceous–Paleogene mass extinction, which resulted in the extinction of 92.5% of all species. The extinction phase lasted 5.4 million years and was followed by a recovery period of 6.9 million years. However, present extinction rates in European freshwater gastropods are three orders of magnitude higher than even these revised estimates for the Cretaceous–Paleogene mass extinction. Our results indicate that, unless substantial conservation effort is directed to freshwater ecosystems, the present extinction crisis will have a severe impact to freshwater biota for millions of years to come.

Extinction risk is linked to lifestyle in freshwater gastropods

“…The dataset includes faunas from Scandinavia in the North to Cyprus in the South, the Azores and Iceland in the West to the Caspian Sea realm in the East (Figure 1). Turkey, the Caucasus countries and Turkmenistan (as part of the Caspian Sea Basin) were included because of their European biogeographic affinities (compare Neubauer et al, 2021). The final dataset includes 27,790 occurrences of 2,109 species from 5,374 localities (Figure 1).…”

“…Also, environmental and climatic factors and, in the Anthropocene, human impact certainly play a role in driving extinction of freshwater gastropods (Cordellier et al, 2012;Georgopoulou et al, 2016;Neubauer et al, 2021), whereas the two systematic groups may suffer from and react differently to selected pressures. Nonetheless, the differences among Caenogastropoda and Hygrophila concerning the abovementioned lifestyle traits, which are consistent through geological time, support our hypothesis that the discrepancy we found in their extinction likelihood is at least to some degree a result of lifestyle.…”

“…Freshwater environments and their biota experience critical threats at present (Böhm et al, 2020;Darwall et al, 2020;De Grave et al, 2015;Dudgeon, 2020;Garcia-Moreno et al, 2014;Neubauer et al, 2021;Pimm et al, 2014;Poff et al, 2012;Vörösmarty et al, 2010). Climate change, water pollution, habitat degradation and invasion by exotic species are but a few of the many threats straining modern freshwater biodiversity (Albert et al, 2021;Bowler et al, 2017;Dudgeon et al, 2006;Heino et al, 2009).…”

“…As concern invertebrates, about one third of the species of freshwater crabs (Cumberlidge et al, 2009), crayfish (Richman et al, 2015) and molluscs (Böhm et al, 2020) are globally threatened with extinction. Several studies have predicted future freshwater biodiversity loss as a direct or indirect consequence of human impact (e.g., Cordellier et al, 2012;Janse et al, 2015;Markovic et al, 2014;Neubauer et al, 2021;Pereira et al, 2010). Unless serious effort is directed towards freshwater biota and the ecosystems they live in, we are likely to steer into a sixth mass extinction event within the millennium (Neubauer et al, 2021).…”

“…Several studies have predicted future freshwater biodiversity loss as a direct or indirect consequence of human impact (e.g., Cordellier et al, 2012;Janse et al, 2015;Markovic et al, 2014;Neubauer et al, 2021;Pereira et al, 2010). Unless serious effort is directed towards freshwater biota and the ecosystems they live in, we are likely to steer into a sixth mass extinction event within the millennium (Neubauer et al, 2021).…”