Oligocene vegetation of Europe and western Asia—Diversity change and continental patterns reflected by plant functional types

Abstract

Spatial vegetation patterns potentially reflect coeval continental climate variations which are also impacted by palaeogeographical settings. Plant functional types (PFTs) and their distribution, frequently applied in ecological studies and biome modelling, serve as a tool for reconstructing palaeovegetation units and ultimately tracing palaeoecological/climate gradients. Earlier quantitative studies focusing on distribution patterns of PFTs and designed to put forward data‐model comparisons were carried out on well‐dated Middle and Late Miocene floras. Moreover, the PFT approach has been successfully applied to reconstruct Eocene vegetation patterns in several time slices at a global scale as well as in regional vegetation reconstructions throughout the Cenozoic. In the current study, a PFT approach with 41 different classes is applied on Rupelian and Chattian fossil floras of Europe and western Asia to infer spatial vegetation differences across the study area. A comprehensive palaeobotanical record including ~163 macro‐ (leaves, fruits and seeds) and microfloras was compiled. The floristic components of these palaeofloras are translated to PFTs including herbaceous to arboreal classes. The PFTs are defined using traits and climatic thresholds of key taxa, and comprise species assigned by morphological and phenological features with respect to the related ecosystem. Diversity values of each PFT are calculated for the fossil floras and spatial gradients over western Eurasia are investigated for the Rupelian and Chattian. PFT diversity maps and transects for both time slices reveal basic patterns of the vegetational structure at the continental scale. It is shown that in both time slices studied tropical and broadleaved evergreen PFTs were more diverse in the West and at lower latitudes. Consistently with the global climate evolution as known from marine archives and regional continental records their level was higher in the Rupelian compared to the Chattian. All over low diversities of xeric PFTs coincide with the previously assumed dominance of humid climate conditions in western Eurasia throughout the Oligocene, however, the reconstructed spatial gradients suggest somewhat drier conditions to the southwest and southeast of the study area.

Rupelian Kazakhstan floras in the context of early Oligocene climate and vegetation in Central Asia

“…The Toguzken macroflora is more similar to floras of VU 2, broadleaved deciduous forest, due to its arboreal spectrum, representing a more temperate vegetation type mainly distributed in the mid-latitudes. The arboreal spectrum of the Toguzken microflora likewise points to a midlatitudinal temperate vegetation type, namely, the VU 3 type, mixed mesophytic forest with diverse conifers, but being at the cool end of this formation due to its low proportion of broadleaved evergreens, as reported from Western Siberia (Utescher et al, 2020). Thus, the PFT spectra of the Toguzken macro-and microflora provide complementary evidence on a widely distributed temperate regional vegetation type, but under differing edaphic filtering conditions.…”

“…There is a low proportion of swamp tress (PFT 18) and a higher proportion of drought-tolerant PFTs (19-20) in the Kusto flora, as was also noted in the Kara-Biryuk leaf flora spectrum of eastern Kazakhstan(Popova et al, 2017); these findings suggest the same floral type. The Toguzken flora is more similar to the coeval Kiin-Kerish flora (eastern Kazakhstan), according to proportions of these mentioned PFTs.In view of larger-scale, continental vegetation patterns, a reconstruction for two Oligocene time slices allows for comparison with ecospectra of Europe and western Asia(Utescher et al, 2020).Utescher et al (2020) conducted a principle component analysis on diversity data of woody PFTs and yielded a total of eight groups that were interpreted in terms of vegetation units (VUs). According to its arboreal component, the Kusto flora resembles spectra of VU 4…”

Paleogene vegetation changes in Primorye, Far East of Russia: A study based on diversity of plant functional types

“…In the LF, the proportion of herbaceous plants is higher (0–26.3%) and varies more significantly (Table 4 and Figure 3). Usually, herbs are not well represented in LF but diverse in PF and carpofloras (Popova, Utescher, Gromyko, Mosbrugger, & François, 2018; Utescher et al (2020)). In our floras, high percentages of herbs are obtained in a single leaf flora only (the Late Eocene LF 18).…”

Late Eocene to Late Miocene palaeoecological and palaeoenvironmental dynamics of the Ereğli‐Ulukışla Basin (Southern Central Anatolia)

“…Currently, some parameters (altitude, orography, and land–sea interactions) are causing climate and vegetation change in Europe and Anatolia, and the same parameters have affected the Cenozoic palaeoclimate and palaeovegetation. The palaeovegetational and palaeoclimatic evolution of Europe and Anatolia from the Eocene to Miocene were derived from various studies based on palaeobotanical records (e.g., Bruch, Fauquette, & Bertini, 2002; Bruch & Gabrielyan, 2002; Bruch, Utescher, Alcalde Olivares, Dolakova, & Mosbrugger, 2004; Bruch, Utescher, Mosbrugger, Gabrielyan, & Ivanov, 2006; Denk, Grimm, Grímsson, & Zetter, 2013; Güner et al, 2017; Ivanov, Ashraf, Mosburugger, & Palamarev, 2002; Ivanov, Ashraf, Utescher, Mosbrugger, & Slavomirova, 2007; Ivanov, Bozukov, & Koleva‐Rekalova, 2007; Mosbrugger & Utescher, 1997; Svetlana et al, 2019; Syabryaj, Utescher, & Molchanov, 2007; Uhl, Mosbrugger, Bruch, & Utescher, 2003; Utescher et al, 2012, 2014; Utescher et al, 2020; Utescher, Djordjevic‐Milutinovic, Bruch, & Mosbrugger, 2007; Utescher, Erdei, François, & Mosbrugger, 2007; Utescher, Mosbrugger, Ivanov, & Dilcher, 2009; Worobiec, 2003). Additionally, terrestrial and deltaic sediments deposited in Anatolia have a rich plant microfossil record.…”