This study presents a 14 500-year high-resolution multi-proxy reconstruction of past climate and environmental changes from Lake Nakri in Southern Estonia. Estonia's geographical position at the intersection of maritime and continental climate zones and boreal and nemoral biomes makes it a highly suitable location for studying even relatively small past fluctuations in climate. We used Chironomidae, Cladocera, pollen, and loss-on-ignition analyses to reconstruct mean July air temperatures, to explore changes in continentality expressed as annual temperature range (ATR), and track environmental changes in the catchment (land cover, land use) and in the lake (trophy, pH, etc.), throughout the late glacial and Holocene. Chironomidae and pollen analysis were used to reconstruct July air temperatures. The reconstruction curves are coherent and consistently reveal climate events, apparent around the 9.0-8.0 ka, 7.5-7.0 ka, 6.0-5.5 ka, 1.0-0.5 ka cal BP in the temperature records. The exception to the otherwise consistent proxy pattern is that Chironomidae reveal an earlier onset of Early Holocene warming compared with the pollen record. This discrepancy may be attributed to low local pollen productivity and delayed postglacial vegetation development. The chironomid-based reconstructions show that the Younger Dryas climate was marked by a 3 degrees C drop in summer temperature and increased ATR. Although the chironomid-based continentality (difference in summer and winter temperatures) reconstruction approach is still under development, we present a first tentative chironomid-inferred ATR reconstruction, which revealed a major decreasing trend throughout the postglacial. Cladocera remains were used to evaluate past changes in nutrient status and we found no evidence of significant shifts in trophic state and in-lake productivity. Therefore, we conclude that the chironomid-based reconstruction was not biased by such changes. The resulting reconstructions provide critical insights into past regional climate variability and ecosystem responses in eastern temperate-boreal ecotones. Our new palaeotemperature curves can serve as a reference for future regional climate studies.

High-latitude ecosystems are undergoing rapid climate warming, yet long-term ecological response remain poorly understood due to the scarcity of sustained monitoring records. We analyse a unique 40-year dataset from a subarctic mountain birch (Betula pubescens ssp. czerepanovii) ecosystem in northern Fennoscandia, integrating climate, plant reproduction, insect herbivory, phenology, and large herbivore performance. Mean annual temperature increased by 0.6 degrees C per decade since 1981. Despite strong warming signal, ecosystem dynamics were dominated by cyclic biotic interactions rather than linear effects of climate warming. Birch reproductive indicators (pollen accumulation rate and catkin production) and reindeer calving success exhibited 2-4-year cycles, while geometrid moth populations showed recurrent similar to 10-year outbreak dynamics. While warming weakly correlates with birch reproduction, it is strongly associated with increased moth abundance, establishment of the previously temperature-limited winter moth, and reindeer calving success. Moth outbreaks, combined with reindeer grazing pressure, led to birch defoliation and delayed post-outbreak recovery lasting 6-8 years. Potential positive effect of climate warming on mountain birch reproduction in subarctic ecosystem is, therefore, largely counterbalanced by increased herbivory pressure. Birch flowering and moth larval emergence phenology remained tightly synchronized, with no detectable phenological mismatch under warming. This indicates substantial phenological plasticity, likely reflecting adaptation to historically high interannual climate variability. Our results demonstrate that climate impacts in subarctic ecosystems are best captured by multi-trophic biotic indicators reflecting trophic interactions, disturbance regimes, and species redistribution. We highlight the critical role of long-term monitoring for adaptive ecosystem management planning under continued climate change.

This study presents a multi-proxy reconstruction of Holocene growing season thermal conditions (GDD5) in Central Europe based on Betula nana subfossil leaf micro-phenology and pollen data from a 12-m-long sediment sequence at Linje peatland. A site-specific inference model was developed using modern B. nana leaves to estimate growing season heat accumulation. The model shows lower sensitivity compared to subarctic calibrations but captures variability in GDD5 within the local climatic range. Overlapping undulation index (UI) values observed in modern and subfossil material across differing thermal conditions highlight the importance of regional calibration. Reconstructed GDD5 trends indicate variability in growing season conditions during the Early Holocene and from ∼5450 cal. yr BP to the present and show the strongest agreement with pollen-based estimates during the first half of the Late Holocene. As GDD5 is an important factor controlling agricultural productivity, such reconstructions are important for understanding past changes in seasonality and their potential implications for prehistoric land use and settlement dynamics. The results demonstrate the applicability of combined micro-phenological and palynological approaches for reconstructing past growing season thermal conditions.

Pollen allergy is an increasing public health concern in Europe, as climate warming alters flowering phenology and airborne-pollen dynamics. This study analysed temporal and spatial changes in pollen seasons in Estonia using aerobiological monitoring data from Tartu, Tallinn, and Pärnu. Temporal changes were assessed by comparing two monitoring periods in Tartu (1990–1998 and 2012–2022), while spatial differences were evaluated across stations in contrasting climatic settings. Annual mean air temperature in Tartu increased by 1.1°C between the two study periods, with the strongest warming occurring in winter and early spring. The results demonstrate a clear advancement of flowering phenology in early-spring taxa. The first day of intensive birch (Betula) flowering advanced by approximately 4 days in Tartu, while alder (Alnus) flowering began substantially earlier in warm years, with first intensive pollen episodes occurring up to 23 days earlier than during the 1990s. Inland Tartu consistently exhibited higher and longer-lasting pollen concentrations than the coastal stations Tallinn and Pärnu. Statistical modelling showed that flowering onset can be predicted with moderate to very high accuracy using temperature-related variables. The best-performing models included mean temperature and daily degrees above 5°C (DD5), while precipitation was not a significant predictor. Model prediction uncertainty ranged from 1–9 days depending on taxon. These findings highlight the need for updated pollen calendars and continuous aerobiological monitoring under ongoing climate warming. Sustained funding is essential to ensure timely and spatially representative pollen information, particularly in small countries where monitoring networks remain vulnerable to financial constraints.

Understanding how past climate variability and human activity shaped northern European landscapes is essential for interpreting present-day environmental change. However, high-resolution Holocene records that capture both climatic and anthropogenic signals in small lake catchments remain relatively scarce in the eastern Baltic region. This study addresses that gap by reconstructing Holocene climate and environmental dynamics from the sedimentary material of Lake Pangodi, a semi-closed basin in southern Estonia. We present a multi-proxy reconstruction of Holocene climate and environmental change based on stable isotope geochemistry, sedimentology, pollen, and chironomid records. Stable isotope data document abrupt environmental changes that coincide with regionally recognized early-middle and middle-late Holocene transitions in northern Europe. The early Holocene (similar to 11,700-8200 cal a BP) was characterized by relatively wet conditions and elevated terrigenous sediment influx. This was followed by a drier and more stable middle Holocene (8200-4200 cal a BP) and a more variable late Holocene (4200 cal a BP-present). Chironomid-inferred temperatures indicate warming during the early Holocene and relatively stable warm season temperatures thereafter. Pollen data reveal transitions from early boreal dominance to temperate forest expansion beginning around 8800 cal a BP, followed by a return to more boreal-dominated assemblages after similar to 4800 cal a BP. Increased crop pollen after similar to 850 cal a BP indicates growing human influence on the landscape. These shifts align with regional vegetation chronozones and reflect both climatic and anthropogenic drivers. An abrupt shift to the highest sediment flux at similar to 4200 cal a BP coincides with the transition to the late Holocene, suggesting a regional environmental reorganization that was likely linked to both climatic and landscape changes, including increased hydrological variability and land surface instability.

It is predicted that continentality, a climate parameter representative of a region's annual temperature and precipitation range, will undergo significant changes in the future. The lack of past continentality reconstructions makes it impossible to decipher any long-term patterns of continentality changes. Here, we investigate the extent to which continentality influences modern chironomid assemblages and evaluate their ecological relevance for palaeolimnological data-based reconstructions of past continentality. We selected 53 lakes along a longitudinal gradient covering the East European Plain (Western part of Russia, Estonia, Latvia) and southern Scandinavia (Sweden and Norway). We analysed the dependency of chironomid assemblages on a variety of environmental parameters including two continentality indices (annual temperature range (ATR) and the Kerner Oceanity Index (KOI)), growing degree days at base temperature 5 °C, mean air temperatures of July, April, and October, number of ice-cover days, lake-water pH, loss-of-ignition and water depth using redundancy analysis. Correlations between all variables were tested to check for possible confounding effects. KOI had the highest explanatory power of 18.4% in the dataset and an absence of collinearity (correlation index < 0.7) with all the other tested variables. Further, we estimated weighted average optima to investigate the distribution of the morphotypes along the continentality gradient in the dataset. Glyptotendipes pallens-type, Neozavrelia, Polypedilum sordens-type, and Microchironomus showed a preference for a continental climate, while Paratanytarsus penicillatus-type, Pseudorthocladius, Thienemannimyia, and Limnophyes were found mainly in samples from oceanic areas. Weighted averaging-partial least squares regression was used for a trial test of the data, resulting in a promising KOI-based model performance with R2 = 0.73 and RMSEP = 5.1. Despite the relatively small dataset, our study suggests that chironomid data have the potential for further development as a tool for reconstructing palaeocontinentality.

This study aims to compare two neighbouring Eemian palaeolakes in central Poland-Koz & lstrok;ow (hydrologically open) and Struga (hydrologically closed)-to improve our understanding of palaeohydrological changes during the last interglacial period (MIS 5e). Using a multi-proxy approach, including pollen and plant macrofossil data, stable carbon and oxygen isotopes, and grain size distributions, we assess the impact of local hydrological conditions on sedimentation and climatic signals. Biogenic sequences record vegetation succession and climatic fluctuations throughout the Eemian, with Koz & lstrok;ow preserving a more continuous archive, whereas Struga exhibits hydrological instability affecting depositional patterns. Pollen data enabled the identification and detailed characterisation of regional pollen assemblage zones (RPAZ), facilitating correlations with regional frameworks across Western and Eastern Europe. Isotopic records at Koz & lstrok;ow indicate evaporative enrichment linked to river inflow and intensified evaporation. In contrast, Struga functioned as a closed basin, with prolonged water residence time and isotope values reflecting internal hydrological balance. Grain size results highlight contrasting sedimentation regimes, with Koz & lstrok;ow showing a transition towards coarser material, suggesting growing fluvial influence, while Struga reveals episodic hydrological fluctuations within a closed-lake system. Climate reconstructions using PPPbase indicate pronounced seasonality and shifts in precipitation patterns during the interglacial. Our findings underscore the contrasting hydrological regimes of Koz & lstrok;ow and Struga, illustrating how local geomorphology and water balance shaped lake evolution. The palaeobotanical record further enhances understanding of catchment dynamics. By integrating isotopic and biological proxies, this study provides a refined reconstruction of Eemian climate evolution and a valuable framework for future interglacial research in Central Europe and beyond.

The Eastern Baltic area stands out as a unique location due to the finds of Europe’s youngest dated mammoth remains (12.6–11.2 ka cal BP). Our study explores the drastic climate and landcover changes during the extinction of these gigantic herbivores at the Pleistocene/Holocene boundary. We used macrofossil analysis to determine the major contemporary terrestrial plant genera present in the area and used corresponding pollen taxa for REVEALS model-based landcover reconstructions. Our results indicate that these last mammoths utilised the open landcover of the Eastern Baltic, which developed as the continental ice sheet retreated during the termination of the last glaciation. Due to climate warming during the initial stages of the Holocene interglacial, the Eastern Baltic became speedily populated by birch and pine forests. The abrupt disappearance of typical forb-dominated tundra indicators, such as Dryas octopetala, and the fast increase in tree birch marked a shift from an open, tundra-like landscape to a forested one, making the environment inhospitable for mammoths even in northernmost Estonia by the beginning of the Holocene. A comparison between the isotopic values of nitrogen (δ15N) and carbon (δ13C) obtained from mammoths’ molars from 14.3 and 11.3 to 43.5 and 39.1 ka cal BP showed that mammoths experienced a decline in the nutritional value of their diet, resulting in their demise in the Eastern Baltic.

Reference pollen:vegetation data for use in interpreting fossil pollen assemblages may either be collected as surface samples or monitored by means of pollen traps. Surface samples can consist of moss polsters or lake-surface sediment, or exceptionally soil, leaf litter, or snow. The advantage of such samples is that a large number can be collected relatively quickly. Within the resulting pollen assemblage, however, the presence of each taxon has to be expressed in percentage terms. Reference material obtained from pollen traps offers more possibilities since pollen accumulation rates (PARs, grains cm−2 yr−1) can be calculated and the record of each taxon can be considered independently. This allows comparisons over distance and between vegetation regions. The collection of such data requires several years since the annual variation in pollen production, which is determined by climate, is great and it is only the long-term average PAR which reflects vegetation abundance. The number and location of samples and the degree of accompanying vegetation data should be appropriate for the research question to which they will be applied since there is no single standard that is suitable for the whole range of possible uses.

Pollen-based quantitative vegetation reconstructions using multiple sedimentary basins from the same area, along with their quantified relevant pollen source areas, are a powerful means to study how long-term human impact has affected vegetation and shaped the currently protected heritage landscapes at different spatial scales. Our study presents the outcome of a palynological investigation in Karula Upland, south Estonia, for the last 6500 years. Centennial-resolution pollen records from one large (175 ha) and three small (5 ha) lakes, and one small bog (0.1 ha) were used to reconstruct the vegetation at different spatial scales using the Landscape Reconstruction Algorithm. The results are discussed in combination with archaeological sites and historical knowledge. The first signs of small-scale forest clearings connected to local human settlements are already visible in the Middle Stone Age (3100-4100 BCE). The first finds of cereal pollen (2500 BCE) from Lake & Auml;hij & auml;rv suggest that grain crops were introduced to south Estonia during the Late Stone Age. The evidence of local crop farming in Karula is traceable since the Bronze Age. The widespread practice of slash-and-burn agriculture led to a major shift in land-cover with replacement of old-growth forests with the early-successional birch, occupying long-term fallows, during Late Bronze Age and Early Iron Age (700-250 BCE). A notable regression in farming is visible during the second part of the Early Iron Age (100-600 CE), with the most prominent change taking place around 500 CE, roughly coinciding with the 6th century Northern Hemisphere climate cooling and Migration Period. Permanent fields gained importance alongside slash-and-burn cultivation, during the Late Iron Age, ca 600-700 CE, shifting the vegetation composition towards more open land-cover. The similar to 50 % open mosaic land-cover of the heritage landscape, protected today in Karula Upland, was formed during the Late Iron Age. The current study shows that sedimentary basins as close as ca 2 km from each other sometimes tell different stories, highlighting the need to quantify the size of the pollen source area to combine successfully archaeological, historical, and palynological evidence. Quantitative pollen-based vegetation reconstructions provide an environmental context for known, and possibly unknown, archaeological evidence within the pollen source area.

Long-term hydroclimate records provide an opportunity to understand potential drivers of the past, and give context to modern and future climate warming. A wide variety of proxy data now allow for reconstruction of climate variables that were not previously possible. Here we present a multi-proxy dataset including n-alkane 82H (82Hn-alk) values from an open-basin lake in Estonia to reconstruct past hydroclimate conditions for the eastern Baltic region. We complement our sedimentary 82Hn-alk data with existing carbonate-based oxygen stable isotope (818O) data to derive deuterium (d-) excess. We present multiple isotopic records and reconstructed relative humidity (ARH) values over the Holocene, and link these with modern precipitation 82H and 818O values to guide the interpretation of the paleo-proxies. Fossil pollen and chironomid-based temperature reconstructions, as well as biogeochemical data provide additional information for inferring past environmental changes. Our results indicate that the middle Holocene in Estonia had on average 6 +/- 3% higher RH values than the late Holocene. The 818O and 82H values were also higher during the middle Holocene, which we interpret as increased warm season precipitation. Our reconstructed d-excess values were relatively higher during the middle Holocene, indicating a more northerly or cold source water origin, in comparison to the late Holocene. In addition to the paleoclimatic significance, our results show how multiple quantitative proxies can be combined to characterize hydroclimate sensitivity to changes in relative humidity, temperature and moisture source.

Here we present a new eastern Baltic Chironomidae training set (TS) containing 35 sites that was collected and merged with neighbouring published Finnish (82 lakes) and northern part of the Polish (nine lakes) TSs. Chironomidae, non‐biting midges, are known to be strongly responsive to the July air temperature and are widely used to infer palaeotemperature. Several modern analogue‐based TSs necessary for calibrating the relationships between mean July air temperature (MJAT) and chironomids are available for Europe. However, none of these is representative of the transitional climate typical for eastern Baltic (Estonia, Latvia, Lithuania). The Finno–Baltic–Polish TS contains 121 sites and covers a geographically continuous 70–50°N latitudinal and 7 °C (12.1–19.2 °C) MJAT gradient. Canonical correspondence analysis revealed that, among the tested environmental variables (pH, water depth, dissolved oxygen, MJAT), the MJAT explains the highest amount of variation, both for the eastern Baltic separately and the Finno–Baltic–Polish TSs. The weighted averaging–partial least squares‐based cross‐validation test reveals that the Finno–Baltic–Polish TS has a low root mean square error of prediction (0.7 °C) confirming the high reliability of the TS. The temperature optima of the taxa included in the new Finno–Baltic–Polish TS and widely used Swiss–Norwegian TS were examined. The observed dissimilarities can be attributed to the differences in the temperature ranges represented by the TS, the taxonomic identification level, the general cosmopolitan taxa distribution patterns and the influence of TS‐specific geographic position, climatic or environmental conditions. The new Finno–Baltic–Polish TS adds to the knowledge on the modern distribution of Chironomidae taxa and widens the geographical area of reliable Chironomid‐based MJAT reconstructions into the eastern European lowland.

Identifying lake reference conditions is a crucial task for successful lake restoration. A common method is the paleolimnological approach. However, lakes can be influenced by multiple stressors over time, making it necessary to consider possible combined effects.In this study, we aimed to untangle the interpretation of subfossil Cladocera in relation to different environmental parameters in lakes of Baltic states. To determine indicator species that could be used for reconstructing past environmental conditions, we developed a 78-lake surface sediment training set. Lakes were selected to cover gradients of different lake sizes, depths, electrical conductivity (EC), pH, and trophic states. Redundancy analysis (RDA) identified pH, trophic state and EC as significant parameters influencing subfossil Cladocera species composition. Using IndVal.g analysis, we distinguished species that are indicative of a combination of parameters such as pH<6 and EC<100 µS/cm (Alonella excisa, Alona rustica, Polyphemus pediculus, Holopedium gibberum, Drepanothrix dentata), pH>6 and EC>100 µS/cm (Disparalona rostrata, Leydigia leydigi, Pleuroxus uncinatus, Pleuroxus trigonellus), pH>6 and oligotrophic/mesotrophic conditions(Monospilus dispar). We identified species that can be indicative of several parameters that do not necessarily combine (for example, Alonopsis elongata for pH<6 or oligotrophic/mesotrophic conditions or EC<200 µS/cm), or were indicative of only one parameter (for example Paralona pigra, Ophryoxus gracilis – oligotrophy; Bosmina longispina- mesotrophy; Bosmina longirostris – eutrophy; Chidorus sphaericus, Oxyurella tenuicaudis–hypereutrophy; Leptodora kindtii pH>6; Pleuroxus aduncus EC>100 µS/cm). These findings add to the understanding of subfossil Cladocera species interpretation in paleolimnological samples, enabling better assessment of anthropogenic influence and reference conditions of lake ecosystems.

Reliable quantitative vegetation reconstructions for Europe during the Holocene are crucial to improving our understanding of landscape dynamics, making it possible to assess the past effects of environmental variables and land-use change on ecosystems and biodiversity, and mitigating their effects in the future. We present here the most spatially extensive and temporally continuous pollen-based reconstructions of plant cover in Europe (at a spatial resolution of 1° × 1°) over the Holocene (last 11.7 ka BP) using the ‘Regional Estimates of VEgetation Abundance from Large Sites’ (REVEALS) model. This study has three main aims. First, to present the most accurate and reliable generation of REVEALS reconstructions across Europe so far. This has been achieved by including a larger number of pollen records compared to former analyses, in particular from the Mediterranean area. Second, to discuss methodological issues in the quantification of past land cover by using alternative datasets of relative pollen productivities (RPPs), one of the key input parameters of REVEALS, to test model sensitivity. Finally, to validate our reconstructions with the global forest change dataset. The results suggest that the RPPs.st1 (31 taxa) dataset is best suited to producing regional vegetation cover estimates for Europe. These reconstructions offer a long-term perspective providing unique possibilities to explore spatial-temporal changes in past land cover and biodiversity.

We compare Holocene tree cover changes in Europe derived from a transient Earth system model simulation (Max Planck Institute Earth System Model - MPI-ESM1.2, including the land surface and dynamic vegetation model JSBACH) with high-spatial-resolution time slice simulations performed in the dynamic vegetation model LPJ-GUESS (Lund-Potsdam-Jena General Ecosystem Simulator) and pollen-based quantitative reconstructions of tree cover based on the REVEALS (Regional Estimates of Vegetation Abundance from Large Sites) model. The dynamic vegetation models and REVEALS agree with respect to the general temporal trends in tree cover for most parts of Europe, with a large tree cover during the mid-Holocene and a substantially smaller tree cover closer to the present time. However, the decrease in tree cover in REVEALS starts much earlier than in the models, indicating much earlier anthropogenic deforestation than the prescribed land use in the models. While LPJ-GUESS generally overestimates tree cover compared to the reconstructions, MPI-ESM indicates lower percentages of tree cover than REVEALS, particularly in central Europe and the British Isles. A comparison of the simulated climate with chironomid-based climate reconstructions reveals that model-data mismatches in tree cover are in most cases not driven by biases in the climate. Instead, sensitivity experiments indicate that the model results strongly depend on the tuning of the models regarding natural disturbance regimes (e.g. fire and wind throw). The frequency and strength of disturbances are - like most of the parameters in the vegetation models - static and calibrated to modern conditions. However, these parameter values may not be valid for past climate and vegetation states totally different from today's. In particular, the mid-Holocene natural forests were probably more stable and less sensitive to disturbances than present-day forests that are heavily altered by human interventions. Our analysis highlights the fact that such model settings are inappropriate for paleo-simulations and complicate model-data comparisons with additional challenges. Moreover, our study suggests that land use is the main driver of forest decline in Europe during the mid-Holocene and late Holocene.

We compare Holocene forest-cover changes in Europe derived from a transient MPI-ESM1.2 simulation with high spatial resolution time-slice simulations conducted in LPJ-GUESS and pollen-based quantitative reconstructions of forest cover based on the REVEALS model (pol-RVs). The dynamic vegetation models and pol-RVs agree with respect to the general temporal trends in forest cover for most parts of Europe, with a large forest cover during the mid-Holocene and substantially smaller forest cover closer to the present time. However, the age of the start of decrease in forest cover varies between regions, and is much older in the pol-RVs than in the models. The pol-RVs suggest much earlier anthropogenic deforestation than the prescribed land-use in the models starting 2000 years ago. While LPJ-GUESS generally overestimates forest cover compared to pol-RVs, MPI-ESM indicates lower percentages of forest cover than pol-RVs, particularly in Central Europe. A comparison of the simulated climate with chironomid-based climate reconstructions reveal that model-data mismatches in forest cover are in most cases not driven by biases in the climate. Instead, sensitivity experiments show that the model results strongly depend on the models tuning regarding natural disturbance regimes (e.g. fire and wind throw). The frequency and strength of disturbances are – like most of the parameters in the vegetation models – static and calibrated to modern conditions. However, these parameter values may not be valid during climate and vegetation states totally different from today’s. In particular, the mid-Holocene natural forests were probably more stable and less sensitive to disturbances than present day forests that are heavily altered by human interventions. Our analysis highlights the fact that such model settings are inappropriate for paleo-simulations and complicate model-data comparisons with additional challenges. Moreover, our study suggests that land-use is the main driver of forest decline in Europe during the mid- and late-Holocene.

This paper studies the impact of land use and land cover change (LULCC) on the climate around 2500 years ago (2.5 ka), a period of rapid transitions across the European landscape. One global climate model was used to force two regional climate models (RCMs). The RCMs used two land cover descriptions. The first was from a dynamical vegetation model representing potential land cover, and the second was from a land cover description reconstructed from pollen data by statistical interpolation. The two different land covers enable us to study the impact of land cover on climate conditions. Since the difference in landscape openness between potential and reconstructed land cover is mostly due to LULCC, this can be taken as a measure of early anthropogenic effects on climate. Since the sensitivity to LULCC is dependent on the choice of climate model, we also use two RCMs. The results show that the simulated 2.5 ka climate was warmer than the simulated pre-industrial (PI, 1850 CE) climate. The largest differences are seen in northern Europe, where the 2.5 ka climate is 2-4 degrees C warmer than the PI period. In summer, the difference between the simulated 2.5 ka and PI climates is smaller (0-3 degrees C), with the smallest differences in southern Europe. Differences in seasonal precipitation are mostly within +/- 10 %. In parts of northern Europe, the 2.5 ka climate is up to 30% wetter in winter than that of the PI climate. In summer there is a tendency for the 2.5 ka climate to be drier than the PI climate in the Mediterranean region. The results also suggest that LULCC at 2.5 ka impacted the climate in parts of Europe. Simulations including reconstructed LULCC (i.e. those using pollen-derived land cover descriptions) give up to 1 degrees C higher temperature in parts of northern Europe in winter and up to 1.5 degrees C warmer in southern Europe in summer than simulations with potential land cover. Although the results are model dependent, the relatively strong response implies that anthropogenic land cover changes that had occurred during the Neolithic and Bronze Age could have affected the European climate by 2.5 ka.

Studies of plants in modern catchment systems can serve to improve the level of understanding of sedimentary plant wax hydrogen isotope (delta 2H) data by directly investigating the link between local climate conditions, plant source water, leaf water, and plant lipids for individual plant species. Here we present such an application to compare two lake catchments with different basin morphologies in Estonia. We sampled leaf and xylem water, as well as leaf waxes from the seven common plant species in each catchment, and soil water. We then measured the delta 2H values of all waters, and of n-alkanes (delta 2Hn-alk) from the plant waxes, as well as surface lake sediments. We applied a Pe ' clet modified Craig-Gordon leaf water model using local precipitation isotope and climate data to characterize the delta 2H values of the biosynthetic source water pool throughout the entire growth season. The data and model results provide a detailed view of how the input hydro-climatic signals from the precipitation delta 2H values were modified by environmental and plant physiological conditions and ultimately by the biosynthetic isotope fractionation associated with n-alkane production by each plant species. We report both average apparent (epsilon app = -92 +/- 21 %o) and biosynthetic (epsilon bio = -132 +/- 19 %o) hydrogen isotope fractionation factors of all species from the studied catchments. This information serves as a foundation for sedimentary organic geochemistry and paleoclimate studies, which allows for more direct and quantitative links to be made between sedimentary plant wax delta 2H values and the climate signal contained in plant source water.

The transition from foraging to farming was a key turning point in ancient socio-economies. Yet, the complexities and regional variations of this transformation are still poorly understood. This multi-proxy study provides a new understanding of the introduction and spread of early farming, challenging the notions of hierarchical economies. The most extensive biological and biomolecular dietary overview, combining zooarchaeological, archaeobotanical, dietary stable isotope and pottery lipid residue analyses is presented, to unravel the nature and extent of early farming in the 3rd millennium cal BCE in the northeast Baltic. Farming was introduced by incoming Corded Ware cultural groups (CWC), but some dietary segregation existed within these communities, with some having more access to domesticates, others incorporating more wild resources into their diet. The CWC groups coexisted in parallel with local hunter-fisher-gatherers (HFG) without any indication of the adoption of domesticates. There was no transition from foraging to farming in the 3rd millennium cal BCE in the NE Baltic. Instead, we see a complex system of parallel worlds with local HFGs continuing forager lifeways, and incoming farmers practising mixed economies, with the continuation of these subsistence strategies for at least a millennium after the first encounter with domesticated animals.