How Did Freshwater Gastropods Respond to the Quaternary Climate Change in Europe?
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Quaternary Science Reviews 149 (2016) 269e278 Contents lists available at ScienceDirect Quaternary Science Reviews journal homepage: www.elsevier.com/locate/quascirev Beginning of a new age: How did freshwater gastropods respond to the Quaternary climate change in Europe? * Elisavet Georgopoulou a, b, , Thomas A. Neubauer a, Giovanni Strona c, Andreas Kroh a, Oleg Mandic a, Mathias Harzhauser a a Geological-Paleontological Department, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria b Institute for Earth Sciences, University of Graz, Heinrichstraße 26, 8010 Graz, Austria c European Commission, Joint Research Centre, Institute for Environment and Sustainability, Forest Resources and Climate Unit, 21027 Ispra, Italy article info abstract Article history: The well documented fossil record of European Quaternary freshwater gastropods offers a unique Received 19 October 2015 resource for continental-scale biogeographical analyses. Here, we assembled a dataset including 338 Received in revised form freshwater gastropod taxa from 1058 localities across Europe, which we used to explore how freshwater 14 July 2016 gastropod communities varied in space and time across six distinct time intervals of the Quaternary, i.e. Accepted 27 July 2016 Gelasian, Calabrian, Middle Pleistocene, Last Interglacial, Last Glacial and Holocene. We took into Available online 10 August 2016 consideration both species richness and qualitative structural patterns, comparing turnover rates be- tween time intervals and examining variations in community nestedness-segregation patterns. Species Keywords: fi Pleistocene richness differed signi cantly between time intervals. The Early Pleistocene showed the highest di- Holocene versity, likely because of the contribution of long-lived aquatic systems like the lakes Bresse and Tiberino Species richness that promoted speciation and endemism. The rich Middle to Late Pleistocene and Holocene assemblages Species turnover were mostly linked to fluvial and/or lacustrine systems with short temporal durations. We identified a Overlap-segregation major turnover event at the Plio-Pleistocene boundary, related to the demise of long-lived lakes and of Range-through approach their rich, endemic faunas at the end of the Pliocene. In the subsequent intervals, little or no turnover Geographical ranges was observed. We also observed a pattern of high segregation in Early Pleistocene communities, asso- ciated with the abundance of endemic species with small distribution ranges, and reflecting the pro- vincial character of the aquatic freshwater systems at that time. This structured pattern disintegrated gradually towards the Middle Pleistocene and remained unstructured up to present. In particular, spatial patterns of community nestedness-segregation in the Last Interglacial and Holocene suggest a random recolonization of freshwater habitats mostly by generalist species following deglaciation. © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). 1. Introduction tectonic activity (e.g. Antonioli et al., 2009; Gabris and Nador, 2007; Stocchi et al., 2005; Zagwijn, 1989). Changes in species diversity The Quaternary Period (2.588e0 Ma; Gibbard et al., 2010), patterns during the Quaternary are usually affiliated with the which can be considered short in a geological perspective, is recurrent glaciations (e.g. Colwell and Rangel, 2010; Dynesius and characterised by successive glacial episodes and distinctly lower Jansson, 2000; Hewitt, 1999; Jansson and Dynesius, 2002), and temperatures compared to the preceding Neogene Period (Lisiecki particularly with the last Ice Age (e.g. Hewitt, 1999, 2000). Qua- and Raymo, 2005). During this time, Europe attained its present ternary ice house conditions affected different animal groups in shape, with extensive changes in shorelines and inland waters different ways as shown, for example, by European insect faunas, occurring mainly because of glacio-isostatic movements and which do not show high extinction rates during the Quaternary, but instead display shifts in their geographical ranges (Coope, 1994). Similarly, changes in species geographical ranges (which, in turn, affected local species richness and composition) have been recor- * Corresponding author. Geological-Paleontological Department, Natural History ded for the Late Pleistocene and Holocene land snail faunas of Museum Vienna, Burgring 7, 1010 Vienna, Austria. north-western Europe (Limondin-Lozouet and Preece, 2014). As E-mail addresses: [email protected], georgelisavet@yahoo. gr (E. Georgopoulou). shown by Neubauer et al. (2015b), the freshwater gastropods of http://dx.doi.org/10.1016/j.quascirev.2016.07.034 0277-3791/© 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). 270 E. Georgopoulou et al. / Quaternary Science Reviews 149 (2016) 269e278 Europe experienced a major turnover at the Plio-Pleistocene divisions were chosen to fit the formal Quaternary subdivisions boundary, and a severe decline in their diversity. The main expla- proposed by Gibbard et al. (2010), hence facilitating comparability, nations of this event have been identified in deteriorating climate, and pinpointing the main glacial event of the Late Pleistocene (i.e. and in the disappearance of long-lived lakes (Neubauer et al., the Last Glacial). All localities extracted from the literature were 2015b). assigned to one of the six TIs based on their stratigraphic age, as While, the distribution of freshwater gastropods during the updated and attributed by Georgopoulou et al. (2015) (see Quaternary is reasonably documented at a regional scale (e.g. Supplementary Table 2). Localities with age ranges crossing a TI's Alexandrowicz, 1999; Esu and Girotti, 1975; Kennard and age boundary were excluded from the dataset except for those Woodward, 1917, 1922; Lozek, 1964; Mania, 1973; Sanko, 2007; where 90% or more of the interval fell within one of the two TIs. Settepassi and Verdel, 1965), a detailed breakdown of trends in Localities with too coarse stratigraphic attributions (e.g. “Early freshwater gastropod biodiversity and biogeography is entirely Pleistocene” or “Late Glacial to Holocene”) were excluded from the missing on a larger scale. Beyond that, a limited number of studies analyses. deal with regional biogeographical patterns, time intervals or taxa, focusing mostly on the terrestrial gastropods (e.g. Limondin- 2.2. Species richness Lozouet and Preece, 2014; Meijer and Preece, 1996). In contrast, the biogeographical relationships of Neogene lacustrine gastropods We examined patterns of species richness across the six TIs. on a pan-European scale have recently been investigated Because of the incomplete fossil record and heterogeneity in (Harzhauser and Mandic, 2008; Neubauer et al., 2015a). These sampling effort, localities included in the dataset are unevenly works identified a trend towards increasing provincialism during distributed and geographically clustered (Fig. 1). Thus, in all TIs, the Neogene, resulting from the formation of large, long-lived lakes information on species distribution is well available in some areas, with highly endemic faunas. By the onset of the Pleistocene, while it is sparse or lacking in others. To cope with the potential however, nearly all of these major hotspots had vanished. confounding effect of this pattern, we created 100 Â 100 km equal- A recent investigation of modern gastropod distribution in Eu- area grid cells in ArcGIS 10 (Esri Inc., 1999e2010) in Behrmann ropean lakes indicates that lacustrine snails still carry the imprint of projection. To ensure that species richness was not overestimated the last Ice Age (Georgopoulou et al., 2016). Here we aim at in areas represented in the dataset by numerous localities, for each unravelling the trends in diversity and spatial structure of the Eu- TI, we calculated the number of species within each grid cell ropean freshwater gastropod fauna throughout the Pleistocene and including at least one locality. Given that the selected grid size Holocene, i.e. the last 2.6 Ma, in order to provide the missing links reflects the explicit character of species distribution records and between the well-resolved patterns of Neogene and modern maintains their spatial accuracy, this procedure should ensure that freshwater gastropod biogeography. For this we compiled a sampling errors related to variation in area sizes are avoided (Kreft comprehensive dataset including available information on the oc- and Jetz, 2010). Average species richness in each TI was defined as currences of European Quaternary freshwater gastropods. We used the quotient of the total number of species divided by the number this dataset to explore how species richness and composition of grid cells with occurrence data. Differences in average species changed throughout six different time intervals, providing the first, richness between TIs were investigated using ANOVA with a detailed biogeographical study of Quaternary freshwater snails at a Dunnett-Tukey-Kramer pairwise multiple comparison post hoc test continental scale. adjusted for unequal variances and sample sizes (see Lau, 2013)or, as in our case, for unequal number of grid cells with occurrence 2. Methods data. In order to explore potential biases related to the uneven spatial 2.1. Taxonomic evaluation and temporal subdivision structure of the dataset,