Palaeoecological Investigations Research Articles

How far from a pristine state are the peatlands in the Białowieża Primeval Forest (CE Europe) – Palaeoecological insights on peatland and forest development from multi-proxy studies

• Multi-proxy palaeoecological studies in the Białowieża Primary Forest. • Palaeoecological analysis as a reliable tool to determinate state of the peatland and forest ecosystems conditions. • Peatland ecosystems in the Białowieża Forest may no longer be in a pristine state. • Permanent high fire activity between ca. 1650 and 1920 in the Białowieża Forest. The Białowieża Primeval Forest is one of the most pristine forested and peatland areas in Europe, as recognized by its status as the World Biosphere Reserve. Palaeoecological analyzes offer the possibility of establishing a record of ecosystem change over time, and therefore setting reference conditions for their assessment, protection and restoration. To assess the impact of hydrological changes, fire and pollution (dust, metals from smelting) on peatland and forest ecosystems, we carried out high-resolution, multi-proxy palaeoecological investigations of two peat cores (50 cm long) from nearby locations at a peatland located in the protected area (nature reserve) of the Białowieża Forest (CE Poland). Our study revealed that: i) between about 1780 and 1920 CE high fire activity likely caused by humans led to a partly decline in dwarf shrubs at the sampling sites; ii) between about 1910 and 1930 CE distinctive changes in local and regional plant succession took place that can be considered as a sign of disturbance in the peatland ecosystems; iii) during the last three decades we recorded a recent decrease of trace metals and pollen indicating a decrease in human activity. These changes are synchronous with a decrease of industrial activity and curbing of emission through legislation as well as the ongoing depopulation of villages in E Poland that started in 1990. Our data suggest that even well-preserved peatlands, located in protected areas might be far from their pristine state, predominantly due to disturbance effects from the past still lingering on. Nevertheless, the studied area remains one of the best-preserved forest ecosystems in Europe, despite the negative impact of human activity (deforestation, fires, hunting) over the past few centuries.

Combining collagen extraction with mineral Zn isotope analyses from a single sample for robust palaeoecological investigations

Collagen extraction from bones or dentine, commonly used for radiocarbon (14C) dating and stable carbon and nitrogen isotope (δ13C and δ15N) analyses, involves the dissolution of the bioapatite of skeletal elements. This fraction is typically disposed of during pretreatment. Here, we test the possibility of utilising this dissolved mineral solution for analysis of the bioapatite zinc isotope composition (δ66Zn). Bioapatite δ66Zn is a novel trophic level indicator similar to collagen δ15N but with isotopic fractionation independent from nitrogen, thus providing additional dietary information. We tested ways to minimise Zn contamination of the dissolved mineral phase during collagen extraction. We then used archaeological bone samples from Ain Difla (Jordan) and Ranis (Germany) to compare δ66Zn values of dissolved bioapatite following our collagen extraction protocol with δ66Zn values from the same sample material dissolved in a metal-free cleanroom. Our results demonstrate that with only minor adjustments to minimise Zn contamination, the dissolved mineral solution from collagen extraction protocols commonly employed for 14C dating and (palaeo)dietary analysis can be used for additional δ66Zn analyses even when collagen extraction does not take place in a cleanroom. Our protocol allows us to gain an additional dietary proxy to complement δ15N trophic level interpretations and perform more robust (palaeo)ecological investigations without further destructive sampling.

Holocene Vegetation Dynamics, Landscape Change and Human Impact in Western Ireland as Revealed by Multidisciplinary, Palaeoecological Investigations of Peat Deposits and Bog-Pine in Lowland Connemara

Palaeoecological investigations, involving pollen analysis, dendrochronology, and radiocarbon dating of bog-pine, provide the basis for reconstruction of vegetation dynamics, landscape development, and human impact in two contrasting parts of lowland northern Connemara, western Ireland, namely Ballydoo and Derryeighter in the east, and Renvyle/Letterfrack/Cleggan at the Atlantic coast some 40 km to the west. The history of Scots pine (Pinus sylvestris) is traced in detail. Standout features include the dominant role the tree played from the early Holocene onwards and especially at Ballydoo, its ability to grow on peat surfaces (so-called pine flush) over the course of several millennia during the mid-Holocene (centred on c. 5 ka), and its demise in a three-step fashion to become regionally extinct at c. 2.3 ka. The factors influencing these developments, including climate change, are discussed. Another natural phenomenon, namely the spread of blanket bog, is shown to be an on-going process since the early mid-Holocene, with accelerated spread taking place during the Neolithic and Bronze Age. The course of human impact, as reflected in pollen records and in archaeological field monuments, including megaliths and prehistoric stone walls, is reconstructed in detail.

New chronology and extended palaeoenvironmental data to the 1975 loess profile of Madaras brickyard, South Hungary

ABSTRACTThe 10 m thick Madaras loess–palaeosol profile is one of the Hungarian outcrops that yielded Upper Palaeolithic artefacts in 1966. To clarify the nature of the deposits and establish a reliable litho‐ and chronostratigraphy, a profile was opened and sampled at 25 cm intervals on the northern side of the brickyard in 1975. Analyses focused on grain size, carbonate content and the mollusc fauna. The chronology was based on the mollusc composition and a single date from the archaeological layer at the depth of ca 7 m below the surface. The 1975 profile was destroyed by mining but the reposited samples allowed an extended analysis of this important Marine Isotope Stage 2 record to which archaeological features were directly assigned. A new absolute chronology was built based on 11 14C dates. Environmental magnetic, geochemical and palaeoecological investigations allowed a refined view of site evolution with reliable chronology for the Last Glacial Maximum. Our results corroborated those of previous investigations done on other coeval loess–palaeosol sequences of the Southern Carpathian Basin. This also allowed for a temporal correlation to another local record with the published high‐resolution chronology of the same brickyard and enabled modelling of local‐scale heterogeneity of the environment in the long run.

Palaeoecology as a Tool for the Future Management of Forest Ecosystems in Hesse (Central Germany): Beech (Fagus sylvatica L.) versus Lime (Tilia cordata Mill.)

In the Central German Uplands, Fagus sylvatica and Picea abies have been particularly affected by climate change. With the establishment of beech forests about 3000 years ago and pure spruce stands 500 years ago, they might be regarded as ‘neophytes’ in the Hessian forests. Palaeoecological investigations at wetland sites in the low mountain ranges and intramontane basins point to an asynchronous vegetation evolution in a comparatively small but heterogenous region. On the other hand, palynological data prove that sustainably managed woodlands with high proportions of Tilia have been persisting for several millennia, before the spread of beech took place as a result of a cooler and wetter climate and changes in land management. In view of increasingly warmer and drier conditions, Tilia cordata appears especially qualified to be an important silvicultural constituent of the future, not only due to its tolerance towards drought, but also its resistance to browsing, and the ability to reproduce vegetatively. Forest managers should be encouraged to actively promote the return to more stress-tolerant lime-dominated woodlands, similar to those that existed in the Subboreal chronozone.

Palaeoecology and conservation of endangered hidden species; example of the liverwort Riella (Riellaceae)

Palaeoecology is increasingly contributing to conservation biology and restoration ecology by extending the recent annual to decennial records of ecological observations to centennial and millennial time scales. One of the almost neglected potential applications of palaeoecological investigations in conservation biology is the discovering of hidden species in subrecent fossil records. Such discoveries can be common in biodiversity hotspots in which the fauna and flora are not still fully known. In this study, we present the case of the liverwort Riella in continental southwest Asia (Iranian plateau), a very vulnerable taxon growing and reproducing under very special ecological circumstances. Our study adds two new species of Riella (R. echinata and R. helicophylla) in addition to the formerly reported R. cossoniana, to the subfossil bryophyte flora of Iran. We demonstrate the important contribution that the genus has played in the history of wetland flora of the semi-arid to arid areas of Iran during the late Quaternary. We further demonstrate the possibility that it is still thriving in many wetland systems and may need to be discovered and then protected in its potential habitats. We suggest that in the biodiversity hotspots of lower latitudes, more attention has to be paid to taxonomic identification of species to reveal the hidden part of the biodiversity for defining better conservation strategies for vulnerable aquatic ecosystems such as the seasonal wetland systems.

‘X’ marks the spot! Sedimentological, geochemical and palaeontological investigations of Upper Cretaceous (Maastrichtian) vertebrate fossil localities from the Vălioara valley (Densuş-Ciula Formation, Hațeg Basin, Romania)

At the beginning of the 20th century, the Croatian-Hungarian palaeontologist Ottokár Kadić discovered a rich Late Cretaceous vertebrate assemblage around Vălioara in the Haţeg Basin, including fossils of several dinosaurs and the lectotype of the eusuchian Allodaposuchus. These fossils were collected from seven main localities and have been housed in the collections of the Mining and Geological Survey of Hungary. However, the collection was mixed after World War II, and this unprovenanced material currently cannot be used for palaeoecological investigations. Nevertheless, the map marking the location of Kadić’s sites has been recently uncovered, showing the positions of the fossiliferous localities, which allows matching these with the historically collected specimens using geochemistry. Based on Kadić’s map, we georeferenced, relocated, and re-excavated these vertebrate-bearing outcrops, and documented their sedimentological context. Detailed stratigraphical investigations of the exposed successions indicate that this Vălioara material represents one of the oldest (earliest Maastrichtian) Late Cretaceous faunal assemblages known from the Haţeg Basin. The vertebrate remains collected during our new excavations around Vălioara represent turtles (Kallokibotion), crocodyliforms (Allodaposuchus, Doratodon, ‘Theriosuchus’, Acynodon), dinosaurs (Zalmoxes, Telmatosaurus, titanosaurs, theropods), and mammals. In order to determine potential geochemical differences among the sites, we selected several specimens with recorded stratigraphic position, measured their trace element compositions, and used these as independent proxies to assess the probable stratigraphic origin of the historical vertebrate fossils. Our detailed sedimentological, geochemical and palaeontological investigations around Vălioara contribute to a deeper understanding of the distribution, evolution and palaeoecology of the Haţeg vertebrate faunas during the latest Cretaceous.

Modern Pollen–Plant Diversity Relationships Inform Palaeoecological Reconstructions of Functional and Phylogenetic Diversity in Calcareous Fens

Predicting the trajectory of ongoing diversity loss requires knowledge of historical development of community assemblages. Long-term data from palaeoecological investigations combined with key biodiversity measures in ecology such as taxonomic richness, functional diversity (FD), phylogenetic diversity (PD) and environmental factors expressed as Ellenberg indicator values (EIVs) could provide that knowledge. We explored the modern pollen–plant (moss polster pollen vs surrounding vegetation) diversity relationships for herbaceous and woody taxa in calcareous fens from two different regions in Estonia, NE Europe. Associations of taxonomic richness, vegetation composition, FD (including functional alpha diversity and trait composition), PD and EIVs in modern pollen vs plant data were studied with correlation analysis, Procrustes analysis and linear regression models. To test their potential use in palaeoreconstructions, diversity measures were applied on pollen data from Kanna spring fen reflecting fen vegetation development over the last nine millennia and diversity changes through time were studied using generalized additive models. Results showed significant pollen–plant richness correlations for herbaceous taxa at vegetation estimate scales up to 6 m radius and Procrustes analysis showed significant compositional associations at all plant estimate scales (up to 100 m). Woody taxa had no significant pollen–plant richness correlations but composition relationships were significant at plant estimate scales of 6–100 m. Traits that were best reflected by pollen data (both in terms of trait composition and functional alpha diversity) among woody and herbaceous taxa were seed number, clonality, SLA and LDMC. PD of herbaceous species was reflected by pollen data. Among the EIVs, Ellenberg L and T were significantly reflected by pollen data for both woody and herbaceous communities. Palaeoreconstruction from Kanna fen indicates that trends of woody taxa are mostly related to long-term changes in climate while diversity variables of herbaceous taxa closely follow autogenic processes within the fen. We suggest that pollen-based diversity estimates should be calculated separately for woody and herbaceous taxa as they clearly represent different spatial scales. Present study suggests that linking sedimentary pollen data with FD, PD and EIVs provides possibilities to examine long-term trends in community assembly and ecosystem processes that would be undetectable from traditional pollen diagrams.

Palaeodietary traits of large mammals from the middle Miocene of Gra\u010danica (Bugojno Basin, Bosnia-Herzegovina)

Recent excavations at the Gračanica coal mine (Bugojno Basin, Bosnia-Herzegovina) have unearthed numerous skeletal parts of fossil vertebrates, including a noteworthy collection of mammalian remains. Previous palaeoecological investigations of the Dinarides Lake System were established using stratigraphical, palaeofloral, and malacological data. However, large mammal remains have so far not been used to reconstruct the terrestrial palaeoenvironment of this important fossil ecosystem. Here, the palaeodietary preferences of large mammals were investigated, using a multiproxy approach by employing dental microwear and dental mesowear analysis, in order to provide new perspectives on the terrestrial palaeoecology of the Dinarides Lake System. The dental microwear of all available adult mammalian teeth was analysed. Dental mesowear analysis was employed for ungulate and proboscidean taxa, using mesowear scores and mesowear angles, respectively. The analysis reveals the presence of browsing, “dirty browsing”, and mixed-feeding herbivorous taxa, with seasonal fruit, or even grass intake. Additionally, the analysis of the carnivores suggests the presence of hyaena- and cheetah-like hypercarnivores, as well as generalists. The palaeodietary traits of the fossil mammals suggest a closed canopy-like environment, which is supported by the fossil plant assemblage. Palaeopalynological data confirm the omnipresence of fleshy fruit-bearing plants, herbaceous taxa, as well as grasses, which justifies the seasonal fruit browsing, the common “dirty browsing”, and the occasional grazing behaviour visualized for some of the fossil mammals from Gračanica.

Taxonomical and palaeoecological investigations of the chondrichthyan and osteichthyan fish remains from the Middle-Late Triassic deposits of the Villány Hills (Southern Hungary)

Two sites in the Villány Hills, Hungary, have yielded rich fish assemblages from Middle to Late Triassic shallow marine deposits. The collected material comes from the Ladinian Templomhegy Dolomite Member and from the Carnian Mészhegy Sandstone Formation. The ichthyofauna is composed of both chondrichthyans (Hybodontidae indet., Palaeobates angustissimus, ‘Polyacrodus’ sp., ?Lissodus sp.) and osteichthyans (Gyrolepis sp., Birgeria sp., and further indeterminate actinopterygians). Despite the large sample size, no remains of neoselachians have been found. The Ladinian Templomhegy Dolomite is dominated by durophagous hybodontiforms (Palaeobates angustissimus, ?Lissodus sp.), but the piscivorous hybodontid and the generalist ‘Polyacrodus’ sp. are missing, while in the fish fauna collected from the Carnian Mészhegy Formation indeterminate piscivorous hybodontids are the most common elements and durophagous forms are much less abundant. The dominance of piscivorous hybodontids in the Carnian Mészhegy Sandstone could be related to the global decrease of diversity of marine fish-eating reptiles (e.g., nothosaurs) or to a change of paleoenvironmental conditions. The present study improves our knowledge on the poorly known Triassic vertebrate faunas of the Tisza Mega-unit, which formed a segment of the passive Neotethys margin of the European Plate and shows an important example of a potential vertebrate faunal shift during the Middle to Late Triassic.

FosSahul 2.0, an updated database for the Late Quaternary fossil records of Sahul

The 2016 version of the FosSahul database compiled non-human vertebrate megafauna fossil ages from Sahul published up to 2013 in a standardized format. Its purpose was to create a publicly available, centralized, and comprehensive database for palaeoecological investigations of the continent. Such databases require regular updates and improvements to reflect recent scientific findings. Here we present an updated FosSahul (2.0) containing 11,871 dated non-human vertebrate fossil records from the Late Quaternary published up to 2018. Furthermore, we have extended the information captured in the database to include methodological details and have developed an algorithm to automate the quality-rating process. The algorithm makes the quality-rating more transparent and easier to reproduce, facilitating future database extensions and dissemination. FosSahul has already enabled several palaeoecological analyses, and its updated version will continue to provide a centralized organisation of Sahul’s fossil records. As an example of an application of the database, we present the temporal pattern in megafauna genus richness inferred from available data in relation to palaeoclimate indices over the past 180,000 years.

A Paleogene leaf flora (Profen, Sachsen-Anhalt, Germany) and its potentials for palaeoecological and palaeoclimate reconstructions

Leaves as main locations of photosynthesis show various adaptations of morphological and anatomical traits to habitat conditions. By implication, leaf traits of fossil dicotyledonous plants can be used as proxies for reconstructions of palaeoenvironmental and palaeoclimatic conditions. Herein, a Paleogene leaf flora, the Profen-Süd LC assemblage from central Germany, is introduced and its leaf traits are outlined. Based on a preliminary phytosociological analysis, a floristic evaluation with respect to modern comparative vegetation refers to azonal communities predominated by a Rhodomyrtophyllum-Steinhauera riparian association. It mirrors local rather but species-divers vegetation. Morphological (shape; margin; venation) and morphometrical (area; leaf mass per area) leaf parameters are determined on a representative subsample and applied to the Trait Combination Type (TCT) analysis for gross-morphological characterization of fossil leaf assemblages, and to quantitative methods for estimation of palaeoclimate parameters: Climate Leaf Analysis Multivariate Program, Coexistence Approach and Leaf Margin Analysis. As a result the assemblage contains only four out of 16 TCTs. Morphological diversity is assumed to be characteristically low as the TCT pattern is not fundamentally distinct from that of the coeval hinterland flora of Kučlin (Czechia). Leaf size is overwhelmingly microphyll, and leaf mass per area values are in accordance with present-day evergreen forests. Main results refer to a sclerophyllous evergreen broad-leaved forest. All palaeoclimate calculations deliver similar estimates for subtropical climate with frost-free winters and humid conditions but certain seasonality in precipitation. Results are briefly discussed in context to depositional environment and taphonomic aspects. Moreover, traces of insect herbivory on the fossil leaves are treated as additional traits beyond classical parameters. Respective patterns are briefly documented and discussed to obtain deeper insights into ecosystem structure and food webs. Finally, this case study gives rise to several open questions about reliability and meaningfulness of fossil leaf traits and the feasibility in palaeoecological investigations.

Thule Inuit environmental impacts on Kangeq, southwest Greenland

Palaeoecological investigations of a rapidly eroding coastal midden and an adjacent peat bog on the island of Kangeq in southwest Greenland have provided new information on environmental change and human impact associated with Thule Inuit occupation. Palynological and palaeoentomological datasets have been produced through the 14th to the 17th centuries AD. The pollen and sedimentary data provide evidence for peat formation, increased frequency of the northern annual herb Koenigia islandica (Iceland purslane) from the end of the 15th century AD, and a decline in shrub pollen over the same period. These changes are interpreted as local responses to Little Ice Age cooling. No clear signal for human impact on the vegetation was revealed in the pollen record, and there was little macroscopic charcoal recovered from either of the sedimentary contexts that were examined; microscopic charcoal evident in the peat column is probably evidence for domestic fires. The insect remains suggest periodic patterns of disposal on the midden and provide information on natural environments in the vicinity. Fossil fly puparia (Diptera) are associated with decaying animal materials and perhaps indicate waste produced from the skinning of marine mammals and birds as opposed to butchering. The faunas contrast with results from the Saqqaq site of Qeqertasussuk and several Norse farms.

Cascading effects between climate, vegetation, and macroinvertebrate fauna in 14,000-year palaeoecological investigations of a shallow lake in eastern Poland

Late glacial and Holocene environmental history of Lake Łukie and its catchment is reconstructed from the lake sediments. This shallow lake is situated in the marshy Polesie region in eastern Poland. Sediments began to accumulate in the lake in the Older Dryas. On the basis of macrofossils, pollen, and Oribatida remains, and with the use of Kohonen’s artificial neural network (self-organising map, SOM), six stages (corresponding to subclusters X1, X2, X3 in cluster X, and Y1, Y2, Y3 in cluster Y) of the lake history were distinguished, and indicator taxa of each stage were identified from the indicator value (IndVal) index. During the transition period corresponding to the border between X and Y, the ecosystem transformed in the broad sense from the protocratic to mesocratic phase in a 5-point scale transformation of the landscape in the glacial–interglacial cycle. All the steps involved in post-glacial history succession during interglacial cycles include changes in climate, soil, and biotic interactions. Indicator taxa for the subsequent SOM subclusters X1, X2, and X3 are associated with the first phase of the protocratic glacial–interglacial cycle. The transformation that occurs on the level of cluster Y (subcluster Y1) is the mesocratic phase (ca. 9000–5000 14C age BP), which is characterised by high temperatures and development of closed forest (climax forest). Subcluster Y2 corresponds to the transformation of forest cover during the oligocratic phase (ca. 5000–3000 14C age BP), which is associated with decreasing forest share and deteriorating soils. Finally, subcluster Y3 can be associated with the telocratic phase, characterised by the influence of a more oceanic climate (from ca. 2500 14C age BP) with declining temperatures, higher humidity, and milder seasonal contrasts, which contributed to the development of more open vegetation and infertile soils. This stage also corresponds to an increased human activity and landscape transformation, such as from forests to cornfields and from wetlands to meadows. Interestingly, the currently strictly protected brittle naiad (Najas minor) was present in the lake during the Atlantic, Subboreal, and Subatlantic periods; however, this species is not listed as being part of the present vegetation and may have become extinct relatively recently.

Palaeoecology and distribution of upper Oligocene–lower Miocene foraminifera in the Qom Formation, the Bagher-Abad section, NE Isfahan, Central Iran

These palaeoecological investigations were carried out on foraminiferal assemblages from the Qom Formation in the Bagher-Abad section, northeast of Isfahan, Central Iran. Foraminiferal analysis of the lower limestone part of the succession revealed correlation with the Chattian zone SBZ (Shallow Benthic Zone) 23, and the overlaying marly strata revealed planktonic foraminifera of the Aquitanian Zone M1 (“Paragloborotalia” kugleri Taxon-range Zone). Finally, the topmost, barren zone, and benthic foraminifera assemblage were correlated with the Burdigalian, based on the regional stratigraphic scheme. Palaeoecological interpretations based on microfaunal composition and abundance of benthic foraminifera revealed that late Oligocene microfossils were dominated by larger foraminifera (Rotaliids), whereas early Miocene assemblage was dominated by miliolids. The foraminiferal associations generally reflect well-oxygenated shallow warm tropical waters within the photic zone (<50 m depth) during the Chattian–Burdigalian. These Oligocene/Miocene foraminiferal assemblages indicated middle shelf and inner shelf with normal marine salinity and oligotrophic-to-mesotrophic conditions.

A 5000-yr record of Afromontane vegetation dynamics from the Drakensberg Escarpment, South Africa

Afromontane environments are sensitive to climatic and environmental change as a consequence of their inherent altitudinal and latitudinal gradients. Palaeoecological investigations have been used in these areas to track ecosystem response to climatic and anthropogenic drivers, and have gained prominence in recent years in the context of the need to understand faunal and floral response to future climate uncertainty. This paper focusses on long-term vegetation history in the Drakensberg Escarpment of South Africa, an area with a long history of human habitation, that is internationally recognised for its conservation importance. Ecologists have hypothesised that human-induced burning during the late Quaternary may have been responsible for the expansion of Afromontane grasslands at the expense of forests, which currently exist as refugial patches within fire-protected valleys. Here we test this argument using empirical palaeoecological evidence derived from a subalpine wetland in the Cathedral Peak area of the Drakensberg Escarpment. An age model derived from eight AMS radiocarbon ages, and supported by a pollen time-marker, is used to provide chronological control. Fossil pollen, and carbon and nitrogen isotope analyses, are combined to reconstruct past vegetation dynamics. Results indicate a lack of major compositional vegetation change over the past 5000 years, suggesting long-term vegetation and climatic stability throughout the record. The pollen data show that grasslands have dominated the region, while forests expanded during the late Holocene, thereby refuting the notion of recent forest reduction in the Drakensberg.

Palaeoecological investigations and 230Th/U dating of the Eemian Interglacial peat sequence from Neubrandenburg-Hinterste Mühle (Mecklenburg-Western Pomerania, NE Germany)

The Eemian Interglacial sequence was explored in the gravel pit ‘Neubrandenburg-Hinterste Mühle’ near Neubrandenburg (NE Germany). The sequence is situated in a former kettle hole depression between underlying Late Saalian till (s. str. Warthe) covered by a Late Weichselian till. Today still visible a 3 m long and max. 2 m wide profile is located on the edge of the former Eemian depression. The limnic sedimentation began during the Late Saalian in a landscape characterized by open herbaceous vegetation. Cool, clear and calcium carbonate-rich lake water dominated, inhabited by Characeae that indicates a presence of stonewort meadows, most typical of waters up to 10 m in depth. The beginning of the Eemian Interglacial succession was characterized by a dominance of scarce birch forest followed by pine forest. The beginning of the mesocratic phase of the Eemian was characterized by the appearance of warm climate indicators and by the development of thermophilic forest communities dominated by oak forest with the appearance of warm climate indicators. The ensuing climate optimum was defined by the encroachment of hazel-oak forest and later by mixed deciduous forest. Limnic sedimentation ceased in the basin during this phase and the end of predominantly limnic conditions is marked by a decrease in the frequency of aquatic plants and an increase in the amount of brown mosses. During the interglacial optimum mixed forests reigned. This phase bears a record of oligotrophication leading to transition mire and raised bog and the aquatic plants vanished. The depression gradually became shallower and was overgrown by a forest cover. During the telocratic phase of the Eemian, communities with pine, birch and fir spread. The end of the interglacial was characterized by a disappearance of the riparian forest and a sporadic appearance of reedswamp plants. At the beginning of the Early Weichselian, a deterioration of climatic conditions resulted in the formation of widespread heaths on acid soils and trees disappeared. In the studied basin the water level fluctuated. The Hinterste Mühle sequence shows the development of a small kettle hole lake and its transformation to an overgrowing mire, including terrestrialization processes, during the Eemian Interglacial. The U/Th data obtained for five samples from the upper part of the studied profile, which have been analyzed by the TSD technique, has yielded an age of 116 ± 13/10 kyr. This date reflects the classification into the second half of the Eemian Interglacial and the Early Weichselian for the upper part of peat formation.

Taphonomical and palaeoecological investigation of the Late Cretaceous (Maastrichtian) Tuştea vertebrate assemblage (Romania; Haţeg Basin) - insights into a unique dinosaur nesting locality

The Tuştea vertebrate locality, at Oltoane Hill (northwestern part of the Hațeg Basin, Romania), has provided a rich and diverse assemblage of Late Cretaceous (Maastrichtian) continental vertebrates. More than 800 vertebrate fossils were recovered from this locality; the isolated and associated remains represent 21 different taxa including amphibians, turtles, lizards, snakes, crocodyliforms, pterosaurs, dinosaurs and mammals. The local assemblage is overwhelmingly dominated by dinosaurs, with the rhabdodontid Zalmoxes as the most abundant taxon. The bonebeds that yielded this fossil material occur in a stacked series of mudstone/calcrete units belonging to the middle member of the Densuş-Ciula Formation. The taphonomical investigations suggest that the Tuştea assemblage is made up of attritionally accumulated politaxic remains and that it is a parautochthonous assemblage with no evidence for significant bone transport or reworking.According to the synthesis of all available field data two outstanding fossiliferous levels can be identified within the Tuştea locality, where Megaloolithus eggs and hadrosauroid hatchling material are preserved together, recognized here as two superposed nesting grounds. Such co-occurrence was considered controversial, since there is a long-standing and quasi-general consensus that eggs of the Megaloolithus oogenus were laid by titanosaurian sauropods. We present several alternative scenarios to account for the co-occurrence of Telmatosaurus hatchling remains and megaloolithid eggs in the nesting horizons and explore these alternative hypotheses by weighing the arguments supporting or contradicting them. The burden of evidence derived from our sedimentological, taphonomical and palaeoecological investigations at Tuştea is still in favour of the autochthony of the hatchlings, preserved within their own nesting grounds, whereas there is no such support for a titanosaurian origin of the Tuștea megaloolithid eggs.

Unveiling exceptional Baltic bog ecohydrology, autogenic succession and climate change during the last 2000 years in CE Europe using replicate cores, multi-proxy data and functional traits of testate amoebae

We present the results of high-resolution, multi-proxy palaeoecological investigations of two parallel peat cores from the Baltic raised bog Mechacz Wielki in NE Poland. We aim to evaluate the role of regional climate and autogenic processes of the raised bog itself in driving the vegetation and hydrology dynamics. Based on partly synchronous changes in Sphagnum communities in the two study cores we suggest that extrinsic factors (climate) played an important role as a driver in mire development during the bog stage (500–2012 CE). Using a testate amoebae transfer function, we found exceptionally stable hydrological conditions during the last 2000 years with a relatively high water table and lack of local fire events that allowed for rapid peat accumulation (2.75 mm/year) in the bog. Further, the strong correlation between pH and community-weighted mean of testate amoeba traits suggests that other variables than water-table depth play a role in driving microbial properties under stable hydrological conditions. There is a difference in hydrological dynamics in bogs between NW and NE Poland until ca 1500 CE, after which the water table reconstructions show more similarities. Our results illustrate how various functional traits relate to different environmental variables in a range of trophic and hydrological scenarios on long time scales. Moreover, our data suggest a common regional climatic forcing in Mechacz Wielki, Gązwa and Kontolanrahka. Though it may still be too early to attempt a regional summary of wetness change in the southern Baltic region, this study is a next step to better understand the long-term peatland palaeohydrology in NE Europe

Assessing the fidelity of marine vertebrate microfossil δ18O signatures and their potential for palaeo-ecological and -climatic reconstructions

Conodont biogenic apatite has become a preferred analytical target for oxygen isotope studies investigating ocean temperature and palaeoclimate changes in the Palaeozoic. Despite the growing application in geochemically-based palaeoenvironmental reconstructions, the paucity or absence of conodont fossils in certain facies necessitates greater flexibility in selection of robust oxygen-bearing compounds for analysis. Vertebrate microfossils (teeth, dermal denticles, spines) offer a potential substitute for conodonts from the middle Palaeozoic. Vertebrate bioapatite is particularly advantageous given a fossil record extending to the present with representatives across freshwater to fully marine environments, thus widening the scope of oxygen isotope studies on bioapatite. However, significant tissue heterogeneity within vertebrates and differential susceptibility of these tissues to diagenetic alteration have been raised as potential problems affecting the reliability of the oxygen isotope ratios as palaeoclimatic proxies. Well-preserved vertebrate microfossils and co-occurring conodont fossils from the Upper Devonian and Lower Carboniferous of the Lennard Shelf, Canning Basin, Western Australia, were analysed using bulk (gas isotope ratio mass spectrometry, GIRMS) and in-situ (secondary ion mass spectrometry, SIMS) methodologies, with the latter technique allowing investigation of specific tissues within vertebrate elements. The δ18Oconodont results may be interpreted in terms of palaeolatitudinally and environmentally sensible palaeo-salinity and -temperature and provide a baseline standard for comparison against vertebrate microfossil δ18O values. Despite an absence of obvious diagenetic modification, GIRMS of vertebrate denticles yielded δ18O values depleted in 18O by 2–4‰ relative to co-occurring conodonts. SIMS analysis of dentine tissues exhibited significant heterogeneity, while hypermineralised tissues in both scales and teeth produced δ18O values comparable with those of associated conodonts. The susceptibility of permeable phosphatic fossil tissues to microbial activity, fluid interaction and introduction of mineral precipitates post-formation is demonstrated in the dentine of vertebrate microfossils, which showed significant heterogeneity and consistent depletion in 18O relative to conodonts. The hypermineralised tissues present in both teeth and scales appear resistant to many diagenetic processes and indicate potential for palaeoclimatic reconstructions and palaeoecological investigations.