2023
Kafetzidou A, Fatourou E, Panagiotopoulos K, Marret F, Kouli K.
Vegetation Composition in a Typical Mediterranean Setting (Gulf of Corinth, Greece) during Successive Quaternary Climatic Cycles. Quaternary. 2023;6(2).
AbstractThe Gulf of Corinth is a semi-isolated basin in central Greece interrupting the Pindus Mountain Range, which nowadays is a biodiversity hotspot. Considering its key location, deep drilling was carried out within the International Ocean Discovery Program (IODP; Expedition 381: Corinth Active Rift Development) aiming to improve our understanding of climatic and environmental evolution in the region. Here, we present a new long pollen record from a Mediterranean setting in the southernmost tip of the Balkan Peninsula recording the vegetation succession within the Quaternary. The Corinth pollen record shows no major shifts in arboreal pollen between glacial and interglacial intervals, while Mediterranean and mesophilous taxa remain abundant throughout the study interval. During interglacials, the most frequent reconstructed biomes are cool mixed evergreen needleleaf (CMIX) and deciduous broadleaf forests (DBWB), while graminoid with forb (GRAM) and xerophytic shrubs (XSHB) dominate within glacials. Our findings support the hypothesis that the study area was a significant refugium, providing suitable habitats for Mediterranean, mesophilous and montane trees during successive Quaternary climate cycles.
Fatourou E, Kafetzidou A, Marret F, Panagiotopoulos K, Kouli K.
Late Quaternary Ponto-Caspian dinoflagellate cyst assemblages from the Gulf of Corinth, Central Greece (eastern Mediterranean Sea). [Internet]. 2023:102211.
Publisher's VersionAbstractWe present here the first long Quaternary record of organic-walled dinoflagellate cyst assemblages analysed from sediment cores retrieved during the International Ocean Discovery Program (IODP) Expedition 381 in the Gulf of Corinth. Site M0078A is located in the central part of the Gulf of Corinth (GoC), a semi-isolated marine basin that was repeatedly isolated and reconnected to the Mediterranean Sea during the Quaternary glacial/interglacial cycles. Our results show that dinoflagellate cysts are sorted in two major ecogroups, each group alternating between marine and isolated/brackish conditions. The marine intervals are characterised by high dinocyst diversity whereas the isolated intervals are dominated by taxa thriving in low-salinity conditions such as Spiniferites cruciformis and Pyxidinopsis psilata. In several of these assemblages, S. cruciformis is so prevalent that it forms almost monospecific assemblages. The low salinity dinocyst assemblages are reported for the first time outside the Ponto-Caspian region and they show a close affinity to modern assemblages from the Black Sea, Caspian Sea and Marmara Sea. The alternations between marine and brackish conditions recorded in the Gulf of Corinth reflect changes in surface water salinity (SSS) and temperature (SST), in response to the Quaternary glacial-interglacial cycles. These seem to be in good agreement with regional and global marine isotope and sea-level records. Our findings suggest that the study region sensitively responds to climate forcing at orbital time scales and that local factors most likely drive shifts in dinoflagellate species composition and diversity.
Wagner B, Tauber P, Francke A, Leicher N, Binnie SA, Cvetkoska A, Jovanovska E, Just J, Lacey JH, Levkov Z, et al. The geodynamic and limnological evolution of Balkan Lake Ohrid, possibly the oldest extant lake in Europe. Boreas [Internet]. 2023;52(1):1-26.
Publisher's VersionAbstractStudies of the upper 447m of the DEEP site sediment succession from central Lake Ohrid, Balkan Peninsula, North Macedonia and Albania provided important insights into the regional climate history and evolutionary dynamics since permanent lacustrine conditions established at 1.36 million years ago (Ma). This paper focuses on the entire 584-m-long DEEP sediment succession and a comparison to a 197-m-long sediment succession from the Pestani site ~5 km to the east in the lake, where drilling ended close to the bedrock, to unravel the earliest history of Lake Ohrid and its basin development. 26Al/10Be dating of clasts from the base of the DEEP sediment succession implies that the sedimentation in the modern basin started at c. 2 Ma. Geophysical, sedimentological and micropalaeontological data allow for chronological information to be transposed from the DEEP to the Pestani succession. Fluvial conditions, slack water conditions, peat formation and/or complete desiccation prevailed at the DEEP and Pestani sites until 1.36 and 1.21 Ma, respectively, before a larger lake extended over both sites. Activation of karst aquifers to the east probably by tectonic activity and a potential existence of neighbouring Lake Prespa supported filling of Lake Ohrid. The lake deepened gradually, with a relatively constant vertical displacement rate of ~0.2 mm/a-1 between the central and the eastern lateral basin and with greater water depth presumably during interglacial periods. Although the dynamic environment characterized by local processes and the fragmentary chronology of the basal sediment successions from both sites hamper palaeoclimatic significance prior to the existence of a larger lake, the new data provide an unprecedented and detailed picture of the geodynamic evolution of the basin and lake that is Europe's presumed oldest extant freshwater lake.
2022
Masci L, Vignola C, Liakopoulos GC, Kouli K, Koukousioura O, Aidona E, Moros M, Vouvalidis K, Izdebski A, Masi A.
Landscape Response to Dynamic Human Pressure in the Paliouras Lagoon, Halkidiki Peninsula, Macedonia, Greece. Quaternary. 2022;5(4).
AbstractHigh-resolution pollen analysis of a sediment core recovered from Paliouras lagoon (Greece) allowed us to reconstruct the environmental dynamics of the Halkidiki peninsula during the last 4000 years. Palynological results have been interpreted and compared with detailed historical data, showing distinct phases of human-landscape interactions from the Bronze Age until recent times. Pollen spectra revealed an environment characterized by Mediterranean vegetation, mixed deciduous forest, and pine stands from the Late Bronze Age until the 11th century CE. The first signs of human impact were attested during the Archaic period with the cultivation of Olea, Castanea, and Vitis in the inland of the study area. An intensive land management was highlighted by arboriculture and cereal cultivation (Secale and Hordeum group) in Roman times. Late Antique-Early Medieval times coincided with less human pressure due to warfare-related crises, leading to the expansion of the forest and the abandonment of fields colonized by Amaranthaceae. A massive increase in pastoral activities, suggested by the high percentages of Cichorieae during the Ottoman period, is possibly linked to the significant demographic growth of the nearby city of Thessaloniki in the 16th century CE.
Vignola C, Hättestrand M, Bonnier A, Finné M, Izdebski A, Katrantsiotis C, Kouli K, Liakopoulos GC, Norström E, Papadaki M, et al. Mid-late Holocene vegetation history of the Argive Plain (Peloponnese, Greece) as inferred from a pollen record from ancient Lake Lerna. PLOS ONEPLOS ONE [Internet]. 2022;17(7):e0271548 - .
WebsiteAbstractThis study provides a high-resolution reconstruction of the vegetation of the Argive Plain (Peloponnese, Greece) covering 5000 years from the Early Bronze Age onwards. The well dated pollen record from ancient Lake Lerna has been interpreted in the light of archaeological and historical sources, climatic data from the same core and other regional proxies. Our results demonstrate a significant degree of human impact on the environments of the Argive Plain throughout the study period. During the Early Bronze Age evidence of a thermophilous vegetation is seen in the pollen record, representing the mixed deciduous oak woodland of the Peloponnesian uplands. The plain was mainly used for the cultivation of cereals, whereas local fen conditions prevailed at the coring site. Towards the end of this period an increasing water table is recorded and the fen turns into a lake, despite more arid conditions. In the Late Bronze Age, the presence of important palatial centres modified the landscape resulting in decrease of mixed deciduous oak woodland and increase in open land, partly used for grazing. Possibly, the human management produced a permanent hydrological change at Lake Lerna. From the Archaic period onwards the increasing human pressure in association with local drier conditions caused landscape instability, as attested by a dramatic alluvial event recorded in the Pinus curve at the end of the Hellenistic Age. Wet conditions coincided with Roman times and favoured a forest regeneration pattern in the area, at the same time as we see the most intensive olive cultivation in the pollen record. The establishment of an economic landscape primarily based on pastures is recorded in the Byzantine period and continues until modern times. Overgrazing and fires in combination with arid conditions likely caused degradation of the vegetation into garrigue, as seen in the area of the Argive Plain today.
Ghilardi M, Kinnaird T, Kouli K, Bicket A, Crest Y, Demory F, Delanghe D, Fachard S, Sanderson D.
Reconstructing the Fluvial History of the Lilas River (Euboea Island, Central West Aegean Sea) from the Mycenaean Times to the Ottoman Period. Geosciences [Internet]. 2022;12.
WebsiteAbstractThis paper aims to reconstruct the alluvial activity for the Lilas river, the second-largest catchment of Euboea Island (Central Western Aegean Sea), for approximately the last three and a half millennia. The middle reaches (Gides basin) exhibit several historical alluvial terraces that were first recognised in the 1980s but have remained poorly studied, resulting in uncertain chronological control of palaeofluvial activity. In order to reconstruct the past fluvial dynamics of the Lilas river, a ca. 2.5 m thick stratigraphic profile has been investigated for granulometry and magnetic parameters. Absolute dating of the sediments was possible by applying Optically Stimulated Luminescence (OSL). The results reveal: (i) two coarse-grained aggradational episodes dated from the Mycenaean/Early Iron Age and the Roman periods, respectively, (ii) a phase of rapid fine-grained vertical accretion corresponding to the Late Byzantine to early Venetian periods, (iii) potential evidence for final alluvial deposition from the Little Ice Age/Ottoman period, and (iv) two major incision episodes inferred from Ancient Greek times and most of the Byzantine period. Based on the published core material, the paper also evaluates the direct impacts of the Late Holocene alluviation recorded mid-stream on the fluvial system situated downstream in the deltaic area. Sediment sourcing is attempted based on the magnetic properties of the catchment lithology and of alluvium collected upstream along the main stream bed. Finally, the present paper discusses the possible links between Late Holocene hydroclimatic oscillations and the aggradational/incision phases revealed in the Gides basin. Correlations are attempted with regional palaeoclimate records obtained for the Aegean. In addition to climatic variability, anthropogenic factors are considered: specific land use for agricultural purposes, in particular during the Mycenaean period, the Roman and the Late Byzantine/Early Venetian periods, might have enhanced sediment deposition. Archaeological information and pollen records were also evaluated to reconstruct regional land-use patterns and possible impacts on soil accumulation over the last 3.5 millennia.
Emmanouilidis A, Panagiotopoulos K, Kouli K, Avramidis P.
Late-Holocene paleoenvironmental and land-use changes in Western Greece based on a sediment record from Klisova lagoon. The HoloceneThe Holocene [Internet]. 2022:09596836221080754.
WebsiteAbstractIn this study, we present the findings of a sediment core retrieved from Klisova lagoon, Western Greece, an area with a long record of documented human presence. The recovered deposits were subjected to sedimentological, XRF, and micropaleontological analyses. For the last 4700 cal BP, the freshwater influx, the progradation of the Evinos river delta and related geomorphological changes control the environmental conditions in the lagoon. Considering the centennial temporal resolution of our analyses, small offsets of c.a. 50?years due to lack of regional reservoir correction do not considerably impact the reported radiocarbon ages. Prior to 4000 cal BP, a relatively shallow water depth, significant terrestrial/freshwater input and increased weathering in the lagoon area are inferred. Elemental proxies and increased dinoflagellate cyst and foraminiferal abundances, which indicate marine conditions with prominent freshwater influxes, point to the gradual deepening of the lagoon up to 2000 cal BP. The marine and freshwater condition equilibrium sets at 1300 cal BP, with the lagoonal system reaching its present state. Maxima of anthropogenic pollen indicators during the Mycenaean (3200 cal BP), Hellenistic (2200 cal BP), and Late Byzantine (800 cal BP) periods suggest intervals of increased anthropogenic activities in the area.
Izdebski A, Guzowski P, Poniat R, Masci L, Palli J, Vignola C, Bauch M, Cocozza C, Fernandes R, Ljungqvist FC, et al. Palaeoecological data indicates land-use changes across Europe linked to spatial heterogeneity in mortality during the Black Death pandemic. nature ecology & evolution [Internet]. 2022;6:297–306.
Publisher's VersionAbstractThe Black Death (1347–1352 ce) is the most renowned pandemic in human history, believed by many to have killed half of Europe’s population. However, despite advances in ancient DNA research that conclusively identified the pandemic’s causative agent (bacterium Yersinia pestis), our knowledge of the Black Death remains limited, based primarily on qualitative remarks in medieval written sources available for some areas of Western Europe. Here, we remedy this situation by applying a pioneering new approach, ‘big data palaeoecology’, which, starting from palynological data, evaluates the scale of the Black Death’s mortality on a regional scale across Europe. We collected pollen data on landscape change from 261 radiocarbon-dated coring sites (lakes and wetlands) located across 19 modern-day European countries. We used two independent methods of analysis to evaluate whether the changes we see in the landscape at the time of the Black Death agree with the hypothesis that a large portion of the population, upwards of half, died within a few years in the 21 historical regions we studied. While we can confirm that the Black Death had a devastating impact in some regions, we found that it had negligible or no impact in others. These inter-regional differences in the Black Death’s mortality across Europe demonstrate the significance of cultural, ecological, economic, societal and climatic factors that mediated the dissemination and impact of the disease. The complex interplay of these factors, along with the historical ecology of plague, should be a focus of future research on historical pandemics.
Kafetzidou A, Kouli K, Zidianakis G, Kostopoulos DS, Zouros N.
The early Miocene angiosperm flora of Akrocheiras in Lesvos Petrified Forest (North Aegean, Greece) - Preliminary results. Review of Paleobotany and Palynology [Internet]. 2022;296:104559.
Publisher's VersionAbstractThe pyroclastic rocks of the Lesvos Petrified Forest in the North Aegean comprise one of the early Miocene's most imposing megaflora assemblage. In this area, the new outcrop of Akrocheiras yielded numerous leaf compressions. Based on their macroscopic characteristics, we identified a total of sixteen different taxa, most of them of palaeotropical origin. Dominant species are Daphnogene polymorpha, Pungiphyllum cruciatum and Phoenicites sp., represented by more than 50% of the specimens. Several taxa are new for the Neogene palaeobotanical record of Lesvos Island, such as Laurophyllum sp. 1, Smilax weberi, Celtis japeti, div. Juglandaceae, Ilex miodipyrena, cf. Ilex sp. and Apocynophyllum sp., and provide new floristic data for the area. According to the vegetation analysis, the plant assemblage of Akrocheiras site assigned to lowland/riparian and mesophytic forests on well drained soils. The palaeoclimatic analysis for the new flora revealed a humid warm-temperate climate with seasonal alternations from wetter to drier conditions. The floristic characteristics are outlined, and the record is compared to other ones of the early Miocene period.
2021
Cullen TM, Collier RLE, Hodgson DM, Gawthorpe RL, Kouli K, Maffione M, Kranis H, Eliassen GT.
Deep-Water Syn-rift Stratigraphy as Archives of Early-Mid Pleistocene Palaeoenvironmental Signals and Controls on Sediment Delivery. Frontiers in Earth Science [Internet]. 2021;9:715304.
Publisher's VersionAbstractThe timing and character of coarse siliciclastic sediment delivered to deep-water environments in active rift basins is governed by the complicated interactions of tectonics, climate, eustasy, hinterland geology, and shelf process regime. The stratigraphic archives of deep-water syn-rift basin-fills provide records of palaeoenvironmental changes (e.g. climate and vegetation) in onshore catchments, particularly where they are connected by narrow shelves. However, a chronostratigraphically constrained record of climatic fluctuations and process responses in the hinterland source area recorded in deep-water deposits is rare. Here, we integrate a fully cored research borehole with outcrop exposures of deep-water syn-rift stratigraphy to reconstruct palaeoenvironmental change within the stratigraphy of the West Xylokastro Fault Block in the Corinth Rift, Greece. We used palaeomagnetic and palynological analyses from borehole core samples to develop a chronostratigraphic and palaeoenvironmental model, which we compare to global records of Early-Mid Pleistocene climate and eustatic change. This framework allows establishment of a chronostratigraphic and palaeoenvironmental context to stratigraphic variability encountered in outcrop and in the borehole. Our results show that the ∼240 m thick studied succession was deposited from ∼1.1 to 0.6 Ma across the Early-to Mid-Pleistocene transition. During the Early Pleistocene, obliquity-paced climatic variability is largely coherent with vegetation changes of forest coverage within catchments on the southern margin of the Corinth Rift. Large magnitude, eccentricity-paced cyclicity dominant after the Mid-Pleistocene Transition can alter sediment supply from onshore catchments during the warming stages of severe interglacials where expansion of forest cover may trap sediment within catchments. Conglomeratic grade sediment delivery to the deep-water is enhanced during glacial periods, interpreted to reflect sparse forest cover and large winter storms, and during semi-arid, grassland-dominated interglacial highstands during severe interglacials. Base-level rise during minor interglacials is easily outpaced by high sediment supply and is seldom represented stratigraphically. The study demonstrates the value of integrated palynological and sedimentological studies, whilst applying a conservative approach to interpretation when dealing with sparse palynological records from proximal deep-water stratigraphy. The case study provides conceptual models where climatic and vegetation changes can begin to be incorporated as a key control on sediment flux from onshore drainage basins to deep-water syn-rift successions.
Donders T, Panagiotopoulos K, Koutsodendris A, Bertini A, Mercuri AM, Masi A, Combourieu-Nebout N, Joannin S, Kouli K, Kousis I, et al. 1.36 million years of Mediterranean forest refugium dynamics in response to glacial-interglacial cycle strength. Proceedings of the National Academy of Sciences USA [Internet]. 2021;118(34):e2026111118.
Publisher's VersionAbstractThe sediment record from Lake Ohrid (Southwestern Balkans) represents the longest continuous lake archive in Europe, extending back to 1.36 Ma. We reconstruct the vegetation history based on pollen analysis of the DEEP core to reveal changes in vegetation cover and forest diversity during glacial–interglacial (G–IG) cycles and early basin development. The earliest lake phase saw a significantly different composition rich in relict tree taxa and few herbs. Subsequent establishment of a permanent steppic herb association around 1.2 Ma implies a threshold response to changes in moisture availability and temperature and gradual adjustment of the basin morphology. A change in the character of G–IG cycles during the Early–Middle Pleistocene Transition is reflected in the record by reorganization of the vegetation from obliquity- to eccentricity-paced cycles. Based on a quantitative analysis of tree taxa richness, the first large-scale decline in tree diversity occurred around 0.94 Ma. Subsequent variations in tree richness were largely driven by the amplitude and duration of G–IG cycles. Significant tree richness declines occurred in periods with abundant dry herb associations, pointing to aridity affecting tree population survival. Assessment of long-term legacy effects between global climate and regional vegetation change reveals a significant influence of cool interglacial conditions on subsequent glacial vegetation composition and diversity. This effect is contrary to observations at high latitudes, where glacial intensity is known to control subsequent interglacial vegetation, and the evidence demonstrates that the Lake Ohrid catchment functioned as a refugium for both thermophilous and temperate tree species.
Triantaphyllou MV, TheodoraTsourou, Kouli K, Koukousioura O, Dimiza MD, Aidona EV, Syrides G, Antoniou V, Panagiotopoulos IP, Vandarakis D, et al. Paleoenvironmental Evolution and Sea Level Change in Saronikos Gulf (Aegean Sea, Greece): Evidence from the Piraeus Coastal Plain and Elefsis Bay Sedimentary Records. Water [Internet]. 2021;13.
WebsiteAbstractThorough faunal (benthic foraminifera, ostracods, molluscs) and palynomorph analyses as well as magnetic susceptibility measurements performed on the Piraeus coastal plain sedimentary sequences have shed light on the paleoenvironmental evolution of the area since ca. 9000 cal BP. Benthic and palynomorph assemblages along with magnetic susceptibility suggest a typical lagoonal environment with significant freshwater inputs at the eastern part of the plain after 8700 cal BP. Between 7500 and 5400 cal BP, microfaunal assemblages, mollusc fauna and magnetic susceptibility suggest a shallow marine paleoenvironment, with Piraeus forming a tied island in the center of the bay. Since ca. 4800 cal BP a closed oligohaline lagoon is evidenced in the western part of the Piraeus plain further developed to a marsh after 2800 cal BP, while a coastal environment associated with the fluvio-deltaic system of Kifissos and Korydallos Rivers is continually developing to the west. Signs of cultivation and grazing activities in the area are evidenced since the Early Bronze Age, culminating during the Classical Period. A comparison with a well-dated marine record, recovered from the nearby shallow Elefsis Bay, provides a reasonable estimation of 5 mm/yr for the absolute sea level rise rate in the inner Saronikos Gulf during the Mid-Holocene.
Kouli K, Triantaphyllou MV, Koukousioura O, Dimiza MD, Parinos C, Panagiotopoulos IP, Tsourou T, Gogou A, Mavrommatis N, Syrides G, et al. Late Glacial Marine Transgression and Ecosystem Response in the Landlocked Elefsis Bay (Northern Saronikos Gulf, Greece). Water [Internet]. 2021;13:1505.
Publisher's Version Norström E, West J, Kouli K, Katrantsiotis C, Hättestrand M, Smittenberg RH.
Evaluation of anhydrosugars as a molecular proxy for paleofire activity: A case study on a Holocene sediment core from Agios Floros, Peloponnese, Greece. [Internet]. 2021:104193.
WebsiteAbstractThe anhydrosugars levoglucosan, mannosan and galactosan have been regarded a suitable molecular indicator of natural biomass combustion. Here we evaluate the summed anhydrosugars (SAS) as paleofire indicator in a 6000 year-long fossil core from Agios Floros fen, Peloponnese, Greece, by analyzing charcoal fragments in parallel throughout the sediment sequence. Modern surface soil samples from the same region were analysed for presence of SAS, confirming the biomarker as an indicator of recent fire activity. The highest SAS concentrations in the fossil core were found in sections representing periods of wet conditions both on local and regional scale, and regionally widespread arboreal vegetation. Low or absence of SAS in the fossil core is associated with periods of dryness, regional dominance of non-arboreal vegetation and a fen rather than lake ecosystem at the site. Micro-charcoal fragments were generally more abundant under these conditions. This suggests that SAS yield and deposition may vary with fuel availability and fire behavior which in turn is affected by climate, local moisture and vegetation type. Forest fires result in more SAS compared to grass fires. SAS yield is also favored by low-temperature fires sustained under wet climate conditions. Preservation of SAS is likely to be compromised in the only seasonally wet fen ecosystem under the dry and warm Mediterranean climate conditions. The moist and shallow conditions in the wetland during hot summer months are probably promoting oxidation and biodegradation of the labile SAS molecules compared to the more robust charcoal fragments. Thus, a multiproxy approach - using several proxies, both for fire, hydroclimate and vegetation change - is preferred when aiming to reconstruct past biomass burning from wetland ecosystems in a Mediterranean environment. The micro-charcoal record from Agios Floros reveals significant fire activity between 4400-2800 cal yr BP. This partly overlaps the Bronze Age period, associated with intense human environmental interaction and climate change in this area of Peloponnese, Greece.
Athanasiou M, Triantaphyllou MV, Dimiza MD, Gogou A, Panagiotopoulos I, Arabas A, Skampa E, Kouli K, Hatzaki M, Tsiolakis E.
Reconstruction of oceanographic and environmental conditions in the eastern Mediterranean (Kottafi Hill section, Cyprus Island) during the middle Miocene Climate Transition. [Internet]. 2021;70:100480.
WebsiteAbstractThe multi-proxy investigation of the deep-marine Kottafi Hill section (KHS), a part of the carbonate system of the Miocene Pakhna Formation, Cyprus, involved such proxies as calcareous nannofossil analysis, measurements of the oxygen and carbon isotope composition of the planktonic foraminifer Orbulina universa, and determination of the pollen and palynomorph contents, revealed the importance of these sedimentary sequences in the assessment of the impact of major global events during the middle Miocene on the regional scale. The KHS spans the 20.89–11.6 Ma time interval, during which eighteen OC-rich siltstone intercalated laminae have been deposited under warm and humid climate at 15.5–11.6 Ma. These layers can be possibly considered as the precursors of sapropelic layers mostly developed in the eastern Mediterranean Basin during Pliocene–Holocene. The global glacial events Mi3a–Mi5, traced by δ18O planktonic foraminifera records in the KHS, represent the stepwise cooling phase during the middle Miocene Climate Transition.
2020
Izdebski A, Słoczyński T, Bonnier A, Koloch G, Kouli K.
Landscape Change and Trade in Ancient Greece: Evidence from Pollen Data. The Economic Journal [Internet]. 2020;130(632):2596 - 2618.
Publisher's VersionAbstractIn this article we use pollen data from six sites in southern Greece to study long-term vegetation change in this region from 1000 BCE to 600 CE. Based on insights from environmental history, we interpret our estimated trends in the regional presence of cereal, olive and vine pollen as proxies for structural changes in agricultural production. We present evidence that there was a market economy in ancient Greece and a major trade expansion several centuries before the Roman conquest. Our results are consistent with auxiliary data on settlement dynamics, shipwrecks and ancient oil and wine presses.
Leontaritis AD, Kouli K, Pavlopoulos K.
The glacial history of Greece: a comprehensive review. Mediterranean Geoscience Reviews [Internet]. 2020;2:65–90.
Publisher's VersionAbstractThis paper reviews the glacial history of the mountains of Greece at the southernmost tip of the Balkans, providing a new synthesis of our current understanding of glaciations. The ice cover during the largest Middle Pleistocene glaciations (MIS 12/MIS 6) was more extensive than previously thought. Latest evidence from Mt Chelmos suggests that valley glaciers radiated from a central plateau ice field, whereas the findings of other glacial studies in western Balkans further indicate that extensive ice field/ice caps formed on mountains throughout this region during the Middle Pleistocene glaciations. Ice extent was considerably smaller during the Tymphian Stage (MIS 5d–MIS 2) and this has been confirmed by cosmogenic exposure ages in recent studies on Mt Olympus and Mt Chelmos. During the Holocene, only very small glaciers formed in some deep cirques where they survived because of strong local topoclimatic controls. A comparative analysis with the findings of other glacial and palaeoclimatic studies in the Balkans is also presented to highlight correlations between them. Moisture supply seems to have been the most critical factor for the formation of glaciers in the mountains of Greece. The comparison of Late Pleistocene Equilibrium Line Altitudes (ELAs) across the Balkans indicates a wetter climate in southern Greece that can be attributed to different palaeoatmospheric circulation mechanisms and precipitation regime in central Mediterranean. Conclusively, whilst important information has been added in the last 2 decades, this paper highlights the need for further research in Greece and the wider Balkans to establish the timing and extent of glaciations.
Koukousioura O, Kouli K, Vouvalidis K, Aidona E, Karadimou G, Syrides G.
A multi-proxy approach for reconstructing environmental dynamics since the mid Holocene in Lake Ismarida (Thrace, N. Greece). Revue de micropaléontologie [Internet]. 2020;68:100443.
Publisher's VersionAbstractThe paleoenvironmental evolution of Lake Ismarida in Thrace (Northern Greece) is revealed by the combined lithological, micropaleontological (benthic foraminifera, pollen and NPPS), molluscan analyses, magnetic susceptibility measurement and radiocarbon dating of a 5.8-m long sediment core. The mid Holocene evolution of the lake area is evidenced by the documentation of four sedimentary Units in the core ISMR-2, corresponding to four distinct evolutionary stages: (1) during ∼5500-3500 cal yr BP the lake area was a shallow marine environment characterized by an Ammonia beccarii, small rotaliids, miliolids, Bittium reticulatum and Veneridae spp. assemblage, marine dinoflagellate cysts, and low magnetic susceptibility values; (2) during ∼3500-3000 cal BP the environment is gradually tending to more isolated conditions forming an open lagoon, characterized by marine and euryhaline fauna and low magnetic susceptibility values; (3) during 3000 cal yr BP, the open lagoon presented a transition to an oligohaline inner lagoon, characterized by an Ammonia tepida, Haynesina germanica, Aubignyna perlucida, Pirenella conica, Cerastoderma glaucum and Abra spp. assemblage, sedges and aquatic vegetation. This restricted, entirely isolated from the sea inner lagoon could be definitely used as the landmark of the Lake Ismaris from Heorodotus, while describing the march of Xerxes through Thrace in 480 B.C.; (4) since ∼2000 cal yr BP to the present, the Lake Ismarida is formed, characterized by fresh-water indicators and aquatic pollen, Pseudoschizaea and high magnetic susceptibility values. Finally, the progradation of the Filiouris River deltaic deposits resulted to a 4 km wide deltaic plain between Lake Ismarida and the nowadays coastline. Pollen assemblages record the dominance of a rather rich deciduous forest in the area with traces of human presence in the lower part of the sequence, whereas the opening of the plant landscape under the increasing human pressure is evidenced after ∼ 3000 cal yr BP. Finally, an open vegetation pattern, contemporaneous with the retreat of forest vegetation, is evidenced in the area already before 2000 cal yr BP.
Kouli K.
Tracing human impact on a mountainous plant landscape in Rhodopi Mt (N. Greece) during the last 1100 years. Revue de micropaléontologie [Internet]. 2020;68.
Publisher's VersionAbstractMediterranean mountain ecosystems have been attractive to human societies due to their valuable resources, but are also susceptible to environmental and climate changes. The Rhodope Mountain Range hosts one of the least disturbed natural forests of Europe and is a conservation priority area in the Southern Balkans. Located in the borderlands of the plain of Macedonia, the forest ecosystem development of Rhodope Mountains was shaped not only by Late Holocene climatic variability, but also by changes in human activities since Byzantine times. Palynological and microscopic charcoal analysis of the Livaditis ombrotrophic bog record offers unique insights into vegetation and landscape evolution under the influence of human land-use practices in the south Rhodope area during the last c.a. 1100 years. The findings show a forested landscape, with well-developed Pinus and Abies forests of in the montane zone and mixed deciduous oak forests below that flourished in the area until 900 AD. The expansion of human activity in mountainous areas during the period of Byzantine economic growth (ca. 1000 AD) is evidenced by forest clearance through fire, affecting mainly the Abies populations. The Livaditis record bears evidence about both, arboriculture and cereal cultivation as well as animal husbandry during the first period of human activities in the uplands, while a shift towards pastoralism is most likely associated with the establishment of the Vlach population in the region (ca. 1200 AD). Subsequently, a short-lived expansion of the Pinus percentages could be attributed to the afforestation of abandoned pasture land during the Little Ice Age. Finally, a further intensification of pastoralism is most likely concurrent with the population expansion documented during the Ottoman period (after 1500 AD). The Livaditis pollen record shows significant vegetation shifts in the upland area of southern Rhodope Mountains that could be associated with changes in climate, population mobility and density, as well as evolving land-use practices.
Panagiotopoulos K, Holtvoeth J, Kouli K, Marinova E, Francke A, Cvetkoska A, Jovanovska E, Lacey JH, Lyons ET, Buckel C, et al. Insights into the evolution of the young Lake Ohrid ecosystem and vegetation succession from a southern European refugium during the Early Pleistocene. [Internet]. 2020;227:106044.
WebsiteAbstractMediterranean mid-altitude sites are critical for the survival of plant species allowing for elevational vegetation shifts in response to high-amplitude climate variability. Pollen records from the southern Balkans have underlined the importance of the region in preserving plant diversity over at least the last half a million years. So far, there are no records of vegetation and climate dynamics from Balkan refugia with an Early Pleistocene age. Here we present a unique palynological archive from such a refugium, the Lake Ohrid basin, recording continuously floristic diversity and vegetation succession under obliquity-paced climate oscillations. Palynological data are complemented by biomarker, diatom, carbonate isotope and sedimentological data to identify the mechanisms controlling shifts in the aquatic and terrestrial ecosystems within the lake and its catchment. The study interval encompasses four complete glacial-interglacial cycles (1365–1165 ka; MIS 43–35). Within the first 100 kyr of lake ontogeny, lake size and depth increase before the lake system enters a new equilibrium state as observed in a distinct shift in biotic communities and sediment composition. Several relict tree genera such as Cedrus, Tsuga, Carya, and Pterocarya played an important role in ecological succession cycles, while total relict abundance accounts for up to half of the total arboreal vegetation. The most prominent biome during interglacials is cool mixed evergreen needleleaf and deciduous broadleaf forests, while cool evergreen needleleaf forests dominate within glacials. A rather forested landscape with a remarkable plant diversity provide unique insights into Early Pleistocene ecosystem resilience and vegetation dynamics.
Kyrikou S, Kouli K, Triantaphyllou MV, Dimiza MD, Gogou A, Panagiotopoulos IP, Anagnostou C, Karageorgis AP.
Late Glacial and Holocene vegetation patterns of Attica: A high-resolution record from Elefsis Bay, southern Greece. Quaternary International [Internet]. 2020;545:28–37.
Publisher's VersionAbstractThe present study focuses on the palynological investigation of a sediment core (S2P) recovered from Elefsis Bay, in the western part of Attica Peninsula (southern Greece). Until now, there is quite scarce knowledge about the vegetation history of southern Greece during Late Glacial and Holocene due to a deficiency of long high-resolution pollen records. The analyzed gravity core is a unique continuous and well-dated pollen archive, providing the opportunity for the reconstruction of the plant landscape succession in southern Greece since Late Glacial. In order evidence for the vegetation response to climate oscillations and human impact to be derived, detailed analyses were conducted throughout the sedimentary sequence, spanning the last 13,500 years. The pollen data suggest that temperate deciduous, open oak woodlands of Late Glacial were fully expanded during the onset of Holocene, without any pronounced setback due to climate oscillations as it has been previously indicated by pollen archives from northern Greece. Following this period, Middle Holocene is characterized by the establishment of complex vegetation patterns, partly as the result of human activities, which seem to be the dominant vegetation shaping factor during Late Holocene. Overall, our pollen record highlights the vegetation transition during Late Glacial and Holocene in southern Greece, while offering valuable insight into the plant landscape prior to the first signs of human impact on the environment.
2019
Wagner B, Vogel H, Francke A, Friedrich T, Donders T, Lacey JH, Leng MJ, Regattieri E, Sadori L, Wilke T, et al. Mediterranean winter rainfall in phase with African monsoons during the past 1.36 million years. Nature [Internet]. 2019;573:256-260.
Publisher's VersionAbstractMediterranean climates are characterized by strong seasonal contrasts between dry summers and wet winters. Changes in winter rainfall are critical for regional socioeconomic development, but are difficult to simulate accurately and reconstruct on Quaternary timescales. This is partly because regional hydroclimate records that cover multiple glacial–interglacial cycles, with different orbital geometries, global ice volume and atmospheric greenhouse gas concentrations are scarce. Moreover, the underlying mechanisms of change and their persistence remain unexplored. Here we show that, over the past 1.36 million years, wet winters in the northcentral Mediterranean tend to occur with high contrasts in local, seasonal insolation and a vigorous African summer monsoon. Our proxy time series from Lake Ohrid on the Balkan Peninsula, together with a 784,000-year transient climate model hindcast, suggest that increased sea surface temperatures amplify local cyclone development and refuel North Atlantic low-pressure systems that enter the Mediterranean during phases of low continental ice volume and high concentrations of atmospheric greenhouse gases. A comparison with modern reanalysis data shows that current drivers of the amount of rainfall in the Mediterranean share some similarities to those that drive the reconstructed increases in precipitation. Our data cover multiple insolation maxima and are therefore an important benchmark for testing climate model performance.
Francke A, Dosseto A, Panagiotopoulos K, Leicher N, Lacey JH, Kyrikou S, Wagner B, Zanchetta G, Kouli K, Leng MJ.
Sediment residence time reveals Holocene shift from climatic to vegetation control on catchment erosion in the Balkans. Global and Planetary Change [Internet]. 2019;177:186-200.
Publisher's VersionAbstractUnderstanding the evolution of soil systems on geological time scales has become fundamentally important to predict future landscape development in light of rapid global warming and intensifying anthropogenic impact. Here, we use an innovative uranium isotope-based technique combined with organic carbon isotopes and elemental ratios of sediments from Lake Ohrid (Macedonia/Albania) to reconstruct soil system evolution in the lake's catchment during the last ~16,000 cal yr BP. Uranium isotopes are used to estimated the paleo-sediment residence time, defined as the time elapsed between formation of silt- and clay sized detrital matter and final deposition. The chronology is based on new cryptotephra layers identified in the sediment sequence. The isotope and elemental data are compared to sedimentary properties and pollen from the same sample material to provide a better understanding of past catchment erosion and landscape evolution in the light of climate forcing, vegetation development, and anthropogenic land use. During the Late Glacial and the Early Holocene, when wide parts of the catchment were covered by open vegetation, wetter climates promoted the mobilisation of detrital matter with a short paleo-sediment residence time. This is explained by erosion from deeper parts of the weathering horizon from thin soils. Detrital matter with a longer paleo-sediment residence time, illustrating shallow erosion of thicker soils is deposited in drier climates. The coupling between climatic variations and soil erosion terminates at the Early to Mid-Holocene transition as evidenced by a pronounced shift in uranium isotope ratios indicating that catchment erosion is dominated by shallow erosion of thick soils only. This shift suggests a threshold is crossed in hillslope erosion, possibly as a result of a major change in vegetation cover preventing deep erosion of thin soils at higher elevation. The threshold in catchment erosion is not mirrored by soil development over time, which gradually increases in response to Late Glacial to Holocene warming until human land use during the Late Holocene promotes reduced soil development and soil degradation. Overall, we observe that soil system evolution is progressively controlled by climatic, vegetation, and eventually by human land use over the last ~16,000 years.
McNeill LC, Shillington DJ, Carter GDO, Everest JD, Ber LE, Collier REL, Cvetkoska A, Gelder DG, Diz P, Doan M-L, et al. Expedition 381 methods. In: Proceedings of the International Ocean Discovery Program. Vol. 381. Texas: International Ocean Discovery Program; 2019.
Website McNeill LC, Shillington DJ, Carter GDO, Everest JD, Ber LE, Collier REL, Cvetkoska A, Gelder DG, Diz P, Doan M-L, et al. Expedition 381 summary. In: Proceedings of the International Ocean Discovery Program. Vol. 381. Texas: International Ocean Discovery Program; 2019.
Website McNeill LC, Shillington DJ, Carter GDO, Everest JD, Le Ber E, Collier RE, Cvetkoska A, De Gelder G, Diz P, Doan ML, et al. Site M0078. In: Proceedings of the International Ocean Discovery Program. Vol. 381. Texas: International Ocean Discovery Program; 2019.
Website McNeill LC, Shillington DJ, Everest JD, Ber LE, Cvetkoska A, Gelder DG, Diz P, Ford M, Gawthorpe RL, Geraga M, et al. Site M0079. In: Proceedings of the International Ocean Discovery Program. Vol. 381. Texas: International Ocean Discovery Program; 2019.
Website McNeill LC, Shillington DJ, Carter GDO, Everest JD, Le Ber E, Collier RE, Cvetkoska A, De Gelder G, Diz P, Doan ML, et al. Site M0080. In: Proceedings of the International Ocean Discovery Program. Vol. 381. Texas: International Ocean Discovery Program; 2019.
Website McNeill LC, Shillington DJ, Carter GDO, Everest JD, Le Ber E, Collier RE, Cvetkoska A, De Gelder G, Diz P, Doan ML, et al. Expedition 381 facies associations. In: Proceedings of the International Ocean Discovery Program. Vol. 381. Texas: International Ocean Discovery Program; 2019.
Publisher's Version McNeill LC, Shillington DJ, Carter GDO, Everest JD, Gawthorpe RL, Miller C, Phillips MP, Collier RLE, Cvetkoska A, De Gelder G, et al. High-resolution record reveals climate-driven environmental and sedimentary changes in an active rift. Scientific Reports [Internet]. 2019;9(1):3116.
Publisher's VersionAbstractYoung rifts are shaped by combined tectonic and surface processes and climate, yet few records exist to evaluate the interplay of these processes over an extended period of early rift-basin development. Here, we present the longest and highest resolution record of sediment flux and paleoenvironmental changes when a young rift connects to the global oceans. New results from International Ocean Discovery Program (IODP) Expedition 381 in the Corinth Rift show 10s–100s of kyr cyclic variations in basin paleoenvironment as eustatic sea level fluctuated with respect to sills bounding this semi-isolated basin, and reveal substantial corresponding changes in the volume and character of sediment delivered into the rift. During interglacials, when the basin was marine, sedimentation rates were lower (excepting the Holocene), and bioturbation and organic carbon concentration higher. During glacials, the basin was isolated from the ocean, and sedimentation rates were higher (~2–7 times those in interglacials). We infer that reduced vegetation cover during glacials drove higher sediment flux from the rift flanks. These orbital-timescale changes in rate and type of basin infill will likely influence early rift sedimentary and faulting processes, potentially including syn-rift stratigraphy, sediment burial rates, and organic carbon flux and preservation on deep continental margins worldwide.
Shillington DJ, McNeill LC, Carter GDO, and the Participants E381.
International Ocean Discovery Program Expedition 381: Corinth Active Rift Development. Preliminary Report. College Station, TX ; 2019 pp. 1-36.
Publisher's VersionAbstractExpedition 381 scientists Donna J. Shillington Co-Chief Scientist Lamont-Doherty Earth Observatory Columbia University USA Lisa C. McNeill Co-Chief Scientist Ocean and Earth Science University of Southampton National Oceanography Centre Southampton UK Gareth D.O. CarterExpedition Project Manager British Geological Survey The Lyell Centre UKJeremy (Jez) Everest Expedition Project Manager British Geological Survey The Lyell Centre UKErwan Le BerPetrophysics Staff Scientist School of Geography, Geology and the Environment University of Leicester UK Richard Collier Sedimentologist Basin Structure Group School of Earth and Environment University of Leeds UK Aleksandra Cvetkoska Micropaleontologist (diatoms) Department of Animal Ecology and Systematics Justus Liebig University Germany Gino De Gelder Structural Geologist Institut de Physique du Globe de Paris Sorbonne Paris Cité Université Paris Diderot France Paula Diz FerreiroMicropaleontologist (foraminifers) Departamento Geociencias Marinas y Ordenación del Territorio Facultad de Ciencias del Mar Universidad de Vigo Spain Mai-Linh Doan Petrophysicist (physical properties) Université Grenoble Alpes Université Savoie Mont Blanc CNRS, IRD, IFSTTAR, and ISTerre France Mary Ford Structural Geologist/Sedimentologist CRPG UMR 7358 France Also at Université de Lorraine ENSG INP France Robert GawthorpeSedimentologist Department of Earth Science University of Bergen Norway Maria Geraga Micropaleontologist (foraminifers) Department of Geology University of Patras Greece Jack Gillespie Structural Geologist/Sedimentologist Center for Tectonics, Resources, and Exploration (TRaX) Department of Earth Sciences School of Physical Sciences University of Adelaide AustraliaRomain Hemelsdaël Sedimentologist Géosciences Montpellier Université de Montpellier France Emilio Herrero-Bervera Paleomagnetist University of Hawaii at Manoa Hawaii Institute of Geophysics and Planetology USAMohammad Ismaiel Petrophysicist (physical properties) University Centre for Earth and Space Sciences University of Hyderabad India Liliane Janikian Sedimentologist Departamento de Ciências do Mar Universidade Federal de São Paulo BrazilKaterina Kouli Micropaleontologist (palynology) Department of Geology and Geoenvironment National and Kapodistrian University of Athens Greece Shunli Li Sedimentologist School of Energy Resources China University of Geosciences (Beijing) China Malka Leah Machlus Petrophysicist (physical properties) Lamont-Doherty Earth Observatory Columbia University USA Also at Department of Physical Sciences Kingsborough Community College City University of New York USA Marco MaffionePaleomagnetist School of Geography Earth and Environmental Sciences University of Birmingham UK Carol Mahoney Inorganic Geochemist School of Earth and Environment The University of Leeds UK Georgios Michas Petrophysicist (physical properties) Laboratory of Geophysics and Seismology Technological Educational Institute of Crete Greece Clint Miller Inorganic Geochemist Department of Earth, Environmental and Planetary Sciences Rice University USA Casey Nixon Structural Geologist Department of Earth Science University of Bergen NorwaySabire Asli Oflaz Micropaleontologist (foraminifers) Graduate School “Human Development in Landscapes” Christian-Albrechts-Universität zu Kiel Germany Abah Philip Omale Petrophysicist (physical properties) Department of Geology and Geophysics Louisiana State University USAKostas Panagiotopoulos Micropaleontologist (palynology) Institute of Geology and Mineralogy University of Cologne Germany Sofia Pechlivanidou Sedimentologist Department of Earth Science University of Bergen Norway Marcie Phillips Micropaleontologist (nannofossils/diatoms) Institute for Geophysics University of Texas at Austin USA Simone Sauer Inorganic Geochemist Ifremer Department of Marine Geosciences Centre Bretagne France Joana Seguin Organic Geochemist Institute for Ecosystem Research Christian-Albrechts-Universität zu Kiel GermanySpyros Sergiou Sedimentologist Laboratory of Marine Geology and Physical Oceanography Department of Geology University of Patras Greece Natalia Zakharova Core-Log-Seismic Integration Department of Earth and Atmospheric Sciences Central Michigan University USA
Mercuri AM, Florenzano A, Burjachs F, Giardini M, Kouli K, Masi A, Picornell-Gelabert L, Revelles J, Servera-Vives G, Torri P, et al. From influence to impact: The multifunctional land-use in Mediterranean prehistory emerging from palynology of Archaeological sites (8.2-2.8 ka BP). The Holocene [Internet]. 2019;29(5):830-846.
Publisher's VersionAbstractArchaeobotany is used to discover details on local land uses in prehistoric settlements developed during the middle and beginning of late Holocene. Six archaeological sites from four countries (Spain, Italy, Greece, and Turkey) have pollen and charcoal records showing clear signs of the agrarian systems that had developed in the Mediterranean basin during different cultural phases, from pre-Neolithic to Recent Bronze Age. A selected list of pollen taxa and sums, including cultivated trees, other woody species, crops and annual or perennial synanthropic plants are analysed for land use reconstructions. In general, cultivation has a lower image in palynology than forestry, and past land uses became visible when oakwoods were affected by human activities. On-site palynology allows us to recognise the first influence of humans even before it can be recognised in off-site sequences, and off-site sequences can allow us to determine the area of influence of a site. Neolithic and Bronze Age archaeological sites show similar land use dynamics implying oak exploitation, causing local deforestation, and cultivation of cereal fields in the area or around the site. Although a substantial difference makes the Neolithic influence quite distant from the Bronze Age impact, mixed systems of land exploitation emerged everywhere. Multiple land use activities exist (multifunctional landscapes) at the same time within the area of influence of a site. Since the Neolithic, people have adopted a diffuse pattern of land use involving a combination of diverse activities, using trees–crops–domesticated animals. The most recurrent combination included wood exploitation, field cultivation and animal breeding. The lesson from the past is that the multifunctional land use, combining sylvo-pastoral and crop farming mixed systems, has been widely adopted for millennia, being more sustainable than the monoculture and a promising way to develop our economy.
Weiberg E, Bevan A, Kouli K, Katsianis M, Woodbridge-Fisher J, Bonnier A, Engel M, Finné M, Fyfe RM, Maniatis Y, et al. Long-term trends of land use and demography in Greece: a comparative study. The Holocene [Internet]. 2019;29(5):742-760.
Publisher's VersionAbstractThis paper offers a comparative study of land use and demographic development in northern and southern Greece from the Neolithic to the Byzantine period. Results from summed probability densities (SPD) of archaeological radiocarbon dates and settlement numbers derived from archaeological site surveys are combined with results from cluster-based analysis of published pollen core assemblages to offer an integrated view of human pressure on the Greek landscape through time. We demonstrate that SPDs offer a useful approach to outline differences between regions and a useful complement to archaeological site surveys, evaluated here especially for the onset of the Neolithic and for the Final Neolithic (FN)/Early Bronze Age (EBA) transition. Pollen analysis highlight differences in vegetation between the two sub-regions, but also several parallel changes. The comparison of land cover dynamics between two sub-regions of Greece further demonstrates the significance of the bioclimatic conditions of core locations and that apparent oppositions between regions may in fact be two sides of the same coin in terms of socio-ecological trajectories. We also assess the balance between anthropogenic and climate-related impacts on vegetation and suggest that climatic variability was as an important factor for vegetation regrowth. Finally, our evidence suggests that the impact of humans on land cover is amplified from the Late Bronze Age (LBA) onwards as more extensive herding and agricultural practices are introduced.
2018
Kouli K, Masi A, Mercuri AM, Florenzano A, Sadori L.
Regional vegetation histories: An overview of the pollen evidence from the Central Mediterranean. Late Antique Archaeology [Internet]. 2018;11(1):69-82.
Publisher's VersionAbstractVegetation patterns during the 1st millennium AD in the central Mediterranean, exhibit a great variability, due to the richness of these habitats and the continuous shaping of the environment by human societies. Variations in land use, witnessed in the pollen record, reflect the role that local vegetation and environmental conditions played in the choices made by local societies. The interdisciplinary study of off-site cores remains the key evidence for palaeoenvironmental transformations mirroring the ‘semi-natural’ vegetation, and revealing temporal fluctuations and the amount of human impact on a regional scale.
Marinova E, Harrison SP, Bragg F, Connor S, de Laet V, Leroy SA, Mudie P, Atanassova J, Bozilova E, Caner H, et al. Pollen-derived biomes in the Eastern Mediterranean-Black Sea-Caspian-Corridor. Journal of Biogeography [Internet]. 2018;45(2):484-499.
Publisher's VersionAbstractAim: To evaluate the biomization technique for reconstructing past vegetation in the Eastern Mediterranean–Black Sea–Caspian-Corridor using an extensive modern pollen data set and comparing reconstructions to potential vegetation and observed land cover data. Location: The region between 28–48°N and 22–62°E. Methods: We apply the biomization technique to 1,387 modern pollen samples, representing 1,107 entities, to reconstruct the distribution of 13 broad vegetation categories (biomes). We assess the results using estimates of potential natural vegetation from the European Vegetation Map and the Physico-Geographic Atlas of the World. We test whether anthropogenic disturbance affects reconstruction quality using land use information from the Global Land Cover data set. Results: The biomization scheme successfully predicts the broadscale patterns of vegetation across the region, including changes with elevation. The technique discriminates deserts from shrublands, the prevalence of woodlands in moister lowland sites, and the presence of temperate and mixed forests at higher elevations. Quantitative assessment of the reconstructions is less satisfactory: the biome is predicted correctly at 44% of the sites in Europe and 33% of the sites overall. The low success rate is not a reflection of anthropogenic impacts: only 33% of the samples are correctly assigned after the removal of sites in anthropogenically altered environments. Open vegetation is less successfully predicted (33%) than forest types (73%), reflecting the under-representation of herbaceous taxa in pollen assemblages and the impact of long-distance pollen transport into open environments. Samples from small basins ( < 1 km 2 ) are more likely to be reconstructed accurately, with 58% of the sites in Europe and 66% of all sites correctly predicted, probably because they sample an appropriate pollen source area to reflect regional vegetation patterns in relatively heterogeneous landscapes. While methodological biases exist, the low confidence of the quantitative comparisons should not be over-emphasized because the target maps themselves are not accurate representations of vegetation patterns in this region. Main Conclusions: The biomization scheme yields reasonable reconstructions of the broadscale vegetation patterns in the Eastern Mediterranean–Black Sea–Caspian-Corridor, particularly if appropriate-sized sampling sites are used. Our results indicate biomization could be used to reconstruct changing patterns of vegetation in response to past climate changes in this region.
2017
Norström E, Katrantsiotis C, Smittenberg RH, Kouli K.
Chemotaxonomy in some Mediterranean plants and implications for fossil biomarker records. Geochimica et Cosmochimica Acta [Internet]. 2017;219:96-110.
Publisher's VersionAbstractThe increasing utilization of n-alkanes as plant-derived paleo-environmental proxies calls for improved chemotaxonomic control of the modern flora in order to calibrate fossil sediment records to modern analogues. Several recent studies have investigated long-chain n-alkane concentrations and chain-length distributions in species from various vegetation biomes, but up to date, the Mediterranean flora is relatively unexplored in this respect. Here, we analyse the n-alkane concentrations and chain-length distributions in some of the most common species of the modern macchia and phrygana vegetation in south western Peloponnese, Greece. We show that the drought adapted phrygana herbs and shrubs, as well as some of the sclerophyll and gymnosperm macchia components, produce high concentrations of n-alkanes, on average more than double n-alkane production in local wetland reed vegetation. Furthermore, the chain-length distribution in the analysed plants is related to plant functionality, with longer chain lengths associated with higher drought adaptive capacities, probably as a response to long-term evolutionary processes in a moisture limited environment. Furthermore, species with relatively higher average chain lengths (ACL) showed more enriched carbon isotope composition in their tissues (δ13Cplant), suggesting a dual imprint from both physiological and biochemical drought adaptation. The findings have bearings on interpretation of fossil sedimentary biomarker records in the Mediterranean region, which is discussed in relation to a case study from Agios Floros fen, Messenian plain, Peloponnese. The 6000 year long n-alkane record from Agios Floros (ACL, δ13Cwax) is linked to the modern analogue and then evaluated through a comparison with other regional-wide as well as local climate and vegetation proxy-data. The high concentration of long chain n-alkanes in phrygana vegetation suggests a dominating imprint from this vegetation type in sedimentary archives from this ecotone.
Wagner B, Wilke T, Franke A, Albrecht C, Baumgarten H, Bertini A, Combourieu-Nebout N, Cvetkoska A, D'Addabbo M, Donders TH, et al. The environmental and evolutionary history of Lake Ohrid (FYROM/Albania): interim results from the SCOPSCO deep drilling project. Biogeosciencs [Internet]. 2017;14:2033-2054.
Publisher's VersionAbstractThis study reviews and synthesises existing information generated within the SCOPSCO (Scientific Collaboration on Past Speciation Conditions in Lake Ohrid) deep drilling project. The four main aims of the project are to infer (i) the age and origin of Lake Ohrid (Former Yugoslav Republic of Macedonia/Republic of Albania), (ii) its regional seismotectonic history, (iii) volcanic activity and climate change in the central northern Mediterranean region, and (iv) the influence of major geological events on the evolution of its endemic species. The Ohrid basin formed by transtension during the Miocene, opened during the Pliocene and Pleistocene, and the lake established de novo in the still relatively narrow valley between 1.9 and 1.3 Ma. The lake history is recorded in a 584 m long sediment sequence, which was recovered within the framework of the International Continental Scientific Drilling Program (ICDP) from the central part (DEEP site) of the lake in spring 2013. To date, 54 tephra and cryptotephra horizons have been found in the upper 460 m of this sequence. Tephrochronology and tuning biogeochemical proxy data to orbital parameters revealed that the upper 247.8 m represent the last 637 kyr. The multi-proxy data set covering these 637 kyr indicates long-term variability. Some proxies show a change from generally cooler and wetter to drier and warmer glacial and interglacial periods around 300 ka. Short-term environmental change caused, for example, by tephra deposition or the climatic impact of millennial-scale Dansgaard–Oeschger and Heinrich events are superimposed on the long-term trends. Evolutionary studies on the extant fauna indicate that Lake Ohrid was not a refugial area for regional freshwater animals. This differs from the surrounding catchment, where the mountainous setting with relatively high water availability provided a refuge for temperate and montane trees during the relatively cold and dry glacial periods. Although Lake Ohrid experienced significant environmental change over the last 637 kyr, preliminary molecular data from extant microgastropod species do not indicate significant changes in diversification rate during this period. The reasons for this constant rate remain largely unknown, but a possible lack of environmentally induced extinction events in Lake Ohrid and/or the high resilience of the ecosystems may have played a role.
Peyron O, Combourieu-Nebout N, Brayshaw D, Goring S, Andrieu-Ponel V, Desprat S, Fletcher W, Gambin B, Ioakim C, Joannin S, et al. Precipitation changes in the Mediterranean basin during the Holocene from terrestrial and marine pollen records: a model–data comparison. Climate of the Past [Internet]. 2017;13:249-265.
Publisher's VersionAbstractClimate evolution of the Mediterranean region during the Holocene exhibits strong spatial and temporal variability, which is notoriously difficult for models to reproduce. We propose here a new proxy-based climate synthesis synthesis and its comparison – at a regional (∼ 100 km) level – with a regional climate model to examine (i) opposing northern and southern precipitation regimes and (ii) an east-to-west precipitation dipole during the Holocene across the Mediterranean basin. Using precipitation estimates inferred from marine and terrestrial pollen archives, we focus on the early to mid-Holocene (8000 to 6000 cal yr BP) and the late Holocene (4000 to 2000 cal yr BP), to test these hypotheses on a Mediterranean-wide scale. Special attention was given to the reconstruction of season-specific climate information, notably summer and winter precipitation. The reconstructed climatic trends corroborate the north–south partition of precipitation regimes during the Holocene. During the early Holocene, relatively wet conditions occurred in the south–central and eastern Mediterranean regions, while drier conditions prevailed from 45° N northwards. These patterns then reverse during the late Holocene. With regard to the existence of a west–east precipitation dipole during the Holocene, our results show that the strength of this dipole is strongly linked to the reconstructed seasonal parameter; early-Holocene summers show a clear east–west division, with summer precipitation having been highest in Greece and the eastern Mediterranean and lowest over Italy and the western Mediterranean. Summer precipitation in the east remained above modern values, even during the late-Holocene interval. In contrast, winter precipitation signals are less spatially coherent during the early Holocene but low precipitation is evidenced during the late Holocene. A general drying trend occurred from the early to late Holocene, particularly in the central and eastern Mediterranean.For the same time intervals, pollen-inferred precipitation estimates were compared with model outputs, based on a regional-scale downscaling (HadRM3) of a set of global climate-model simulations (HadAM3). The high-resolution detail achieved through the downscaling is intended to enable a better comparison between site-based paleo-reconstructions and gridded model data in the complex terrain of the Mediterranean; the model outputs and pollen-inferred precipitation estimates show some overall correspondence, though modeled changes are small and at the absolute margins of statistical significance. There are suggestions that the eastern Mediterranean experienced wetter summer conditions than present during the early and late Holocene; the drying trend in winter from the early to the late Holocene also appears to be simulated. The use of this high-resolution regional climate model highlights how the inherently patchy nature of climate signals and paleo-records in the Mediterranean basin may lead to local signals that are much stronger than the large-scale pattern would suggest. Nevertheless, the east-to-west division in summer precipitation seems more marked in the pollen reconstruction than in the model outputs. The footprint of the anomalies (like today, or dry winters and wet summers) has some similarities to modern analogue atmospheric circulation patterns associated with a strong westerly circulation in winter (positive Arctic Oscillation–North Atlantic Oscillation (AO–NAO)) and a weak westerly circulation in summer associated with anticyclonic blocking; however, there also remain important differences between the paleo-simulations and these analogues. The regional climate model, consistent with other global models, does not suggest an extension of the African summer monsoon into the Mediterranean. Therefore, the extent to which summer monsoonal precipitation may have existed in the southern and eastern Mediterranean during the mid-Holocene remains an outstanding question.
2016
Bertini A, Sadori L, Combourieu-Nebout N, Donders TH, Kouli K, Koutsodendris A, Joannin S, Masi A, Mercuri AM, Panagiotopoulos K, et al. All together now: an international palynological team documents vegetation and climate changes during the last 500 kyr at lake Ohrid (SE Europe). Alpine and Mediterranean Quaternary [Internet]. 2016;29(2):201-210.
Publisher's VersionAbstractLake Ohrid (Balkan peninsula) is the oldest European extant lake and one of the deepest and largest. Such a unique, terrestrial natural archive is especially relevant for both paleoenvironmental and paleoclimatic reconstructions but also for genetic studies. In the frame of the International Continental Scientific Drilling Program (ICDP), a deep drilling campaign was carried out within the scope of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project in 2013. Here, we present the summary of palynological analyses carried out in the upper 200 m of the overall 569 m long DEEP site sediment succession from the central part of the lake. These studies, performed by an international palynological team, document the main floristic, vegetation and climate changes during the last ca 500 kyr, at a millennial-scale resolution (~1.6 kyr). The continuous sediment infill permitted to trace multiple non-forested/ forested phases as a response to Glacial/Interglacial cycles as well as to sub-Milankovitch climate changes. The pollen record, corresponding with marine isotope stages MIS 13 to MIS 1, points to a progressive change from cooler and wetter to warmer and drier interglacials. New palynological studies are underway to reconstruct vegetational and climatic conditions over older intervals as well as to obtain high resolution data for some key intervals such as MIS 5-6, MIS 11-12, MIS 35-42. The complete record of changes in flora composition and vegetation during both glacials and interglacials will furnish indispensable insights for understanding the role of refugia, ecosystem resilience and maintenance of terrestrial biodiversity in the Mediterranean area. Gogou A, Triantaphyllou M, Xoplaki E, Izdebski A, Parinos C, Dimiza M, Bouloubassi I, Luterbacher J, Kouli K, Martrat B, et al. Climate variability and socio-environmental changes in the northern Aegean (NE Mediterranean) during the last 1500 years. Quaternary Science Reviews [Internet]. 2016;136:209–228.
Publisher's VersionAbstractAbstractWe provide new evidence on sea surface temperature (SST) variations and paleoceanographic/paleoenvironmental changes over the past 1500 years for the north Aegean Sea (NE Mediterranean). The reconstructions are based on multiproxy analyses, obtained from the high resolution (decadal to multi-decadal) marine record M2 retrieved from the Athos basin. Reconstructed SSTs show an increase from ca. 850 to 950 AD and from ca. 1100 to 1300 AD. A cooling phase of almost 1.5 °C is observed from ca. 1600 AD to 1700 AD. This seems to have been the starting point of a continuous SST warming trend until the end of the reconstructed period, interrupted by two prominent cooling events at 1832 ± 15 AD and 1995 ± 1 AD. Application of an adaptive Kernel smoothing suggests that the current warming in the reconstructed SSTs of the north Aegean might be unprecedented in the context of the past 1500 years. Internal variability in atmospheric/oceanic circulations systems as well as external forcing as solar radiation and volcanic activity could have affected temperature variations in the north Aegean Sea over the past 1500 years. The marked temperature drop of approximately ∼2 °C at 1832 ± 15 yr AD could be related to the 1809 ΑD ‘unknown’ and the 1815 AD Tambora volcanic eruptions. Paleoenvironmental proxy-indices of the M2 record show enhanced riverine/continental inputs in the northern Aegean after ca. 1450 AD. The paleoclimatic evidence derived from the M2 record is combined with a socio-environmental study of the history of the north Aegean region. We show that the cultivation of temperature-sensitive crops, i.e. walnut, vine and olive, co-occurred with stable and warmer temperatures, while its end coincided with a significant episode of cooler temperatures. Periods of agricultural growth in Macedonia coincide with periods of warmer and more stable SSTs, but further exploration is required in order to identify the causal links behind the observed phenomena. The Black Death likely caused major changes in agricultural activity in the north Aegean region, as reflected in the pollen data from land sites of Macedonia and the M2 proxy-reconstructions. Finally, we conclude that the early modern peaks in mountain vegetation in the Rhodope and Macedonia highlands, visible also in the M2 record, were very likely climate-driven.
Weiberg E, Unkel I, Kouli K, Holmgren K, Avramidis P, Bonnier A, Dibble F, Finné M, Izdebski A, Katrantsiotis C, et al. The socio-environmental history of the Peloponnese during the Holocene: Towards an integrated understanding of the past. Quaternary Science Reviews [Internet]. 2016;136:40-65.
Publisher's VersionAbstractPublished archaeological, palaeoenvironmental, and palaeoclimatic data from the Peloponnese in Greece are compiled, discussed and evaluated in order to analyse the interactions between humans and the environment over the last 9000 years. Our study indicates that the number of human settlements found scattered over the peninsula have quadrupled from the prehistoric to historical periods and that this evolution occurred over periods of climate change and seismo–tectonic activity. We show that societal development occurs both during periods of harsh as well as favourable climatic conditions. At some times, some settlements develop while others decline. Well-known climate events such as the 4.2 ka and 3.2 ka events are recognizable in some of the palaeoclimatic records and a regional decline in the number and sizes of settlements occurs roughly at the same time, but their precise chronological fit with the archaeological record remains uncertain. Local socio-political processes were probably always the key drivers behind the diverse strategies that human societies took in times of changing climate. The study thus reveals considerable chronological parallels between societal development and palaeoenvironmental records, but also demonstrates the ambiguities in these correspondences and, in doing so, highlights some of the challenges that will face future interdisciplinary projects. We suggest that there can be no general association made between societal expansion phases and periods of advantageous climate. We also propose that the relevance of climatic and environmental regionality, as well as any potential impacts of seismo-tectonics on societal development, need to be part of the interpretative frameworks.
Sadori L, Koutsodendris A, Masi A, Bertini A, Combourieu-Nebout N, Franke A, Kouli K, Joannin S, Mercuri AM, Panagiotopoulos K, et al. Pollen-based paleoenvironmental and paleoclimatic changes at Lake Ohrid (SE Europe) during the past 500 ka. Biogeosciences [Internet]. 2016;13:1423-1437.
Publisher's VersionAbstractLake Ohrid is located at the border between FYROM (Former Yugoslavian Republic of Macedonia) and Albania and formed during the latest phases of Alpine orogenesis. It is the deepest, the largest and the oldest tectonic lake in Europe. To better understand the paleoclimatic and paleoenvironmental evolution of Lake Ohrid, deep drilling was carried out in 2013 within the framework of the Scientific Collaboration on Past Speciation Conditions (SCOPSCO) project that was funded by the International Continental Scientific Drilling Program (ICDP). Preliminary results indicate that lacustrine sedimentation of Lake Ohrid started between 1.2 and 1.9 Ma ago. Here we present new pollen data (selected percentage and concentration taxa/groups) of the uppermost ∼ 200 m of the 569 m long DEEP core drilled in the depocentre of Lake Ohrid. The study is the fruit of a cooperative work carried out in several European palynological laboratories. The age model of this part of the core is based on 10 tephra layers and on tuning of biogeochemical proxy data to orbital parameters. According to the age model, the studied sequence covers the last ∼ 500 000 years at a millennial-scale resolution ( ∼ 1.6 ka) and records the major vegetation and climate changes that occurred during the last 12 (13 only pro parte) marine isotope stages (MIS). Our results indicate that there is a general good correspondence between forested/non-forested periods and glacial–interglacial cycles of the marine isotope stratigraphy. The record shows a progressive change from cooler and wetter to warmer and drier interglacial conditions. This shift in temperature and moisture availability is visible also in vegetation during glacial periods. The period corresponding to MIS11 (pollen assemblage zone OD-10, 428–368 ka BP) is dominated by montane trees such as conifers. Mesophilous elements such as deciduous and semi-deciduous oaks dominate forest periods of MIS5 (PASZ OD-3, 129–70 ka BP) and MIS1 (PASZ OD-1, 14 ka BP to present). Moreover, MIS7 (PASZ OD-6, 245–190 ka) shows a very high interglacial variability, with alternating expansions of montane and mesophilous arboreal taxa. Grasslands (open vegetation formations requiring relatively humid conditions) characterize the earlier glacial phases of MIS12 (PASZ OD-12, 488–459 ka), MIS10 (corresponding to the central part of PASZ OD-10, 428–366 ka) and MIS8 (PASZ OD-7, 288–245 ka). Steppes (open vegetation formations typical of dry environments) prevail during MIS6 (OD-5 and OD-4, 190–129 ka) and during MIS4-2 (PASZ OD-2, 70–14 ka). Our palynological results support the notion that Lake Ohrid has been a refugium area for both temperate and montane trees during glacials. Closer comparisons with other long southern European and Near Eastern pollen records will be achieved through ongoing high-resolution studies.
2014
Triantaphyllou MV, Gogou A, Bouloubassi I, Dimiza M, Kouli K, Rousakis G, Kotthoff U, Emeis K-C, Papanikolaou M, Athanasiou M, et al. Evidence for a warm and humid Mid-Holocene episode in the Aegean and northern Levantine Seas (Greece, NE Mediterranean). Regional Environmental Change [Internet]. 2014;14(5):1697 - 1712.
Publisher's VersionAbstractMarine and terrestrial biological and biogeochemical proxies in three sediment cores from North and SE Aegean and northern Levantine Seas record continuous warm and humid conditions between 5.5 and 4.0 ka BP related to the establishment of relatively stratified conditions in the upper water column. These conditions may have resulted from the concordant albeit weak Mid-Holocene South Asian monsoon forcing, combined with lighter Etesian winds. During this interval, sea surface temperatures fluctuate in the Aegean Sea, although exhibiting a strong positive shift at*4.8 ka BP. The warm and humid climatic conditions triggered upper water column stratification and enhancement of the deep chlorophyll maximum (DCM), leading to dysoxic conditions and the deposition of a sapropel-like layer, but only in the SE Aegean site. In contrast to the shallow water SE Aegean, the deeper North Aegean and the northern Levantine sites, although experiencing stratification in the upper parts of the water column, did not achieve bottom-water dysoxia. Thus, a top–bottom mechanism of stratification–DCM development accompanied by fast transport and burial of organic matter is a likely explanation for the preservation of productivity signal in the shallow sites of the SE Aegean and establishment of sapropelic conditions during the warm and humid Mid-Holocene. The termination of the Mid-Holocene warm and humid phase coincides with the ‘‘4.2 ka’’ climate event. Our data exhibit an N–S time transgressive aridification gradient around the Aegean Sea, most probably associated with the reorganization of the general atmospheric circulation during the Mid-Holocene.
2013
Peyron O, Magny M, Goring S, Joannin S, De Beaulieu J-L, Brugiapaglia E, Sadori L, Garfi G, Kouli K, Ioakim C, et al. Contrasting patterns of climatic changes during the Holocene across the Italian Peninsula reconstructed from pollen data. Climate of the Past [Internet]. 2013;9(3):1233 - 1252.
Website Sadori L, Bertini A, Combourieu-Nebout N, Kouli K, Mariotti Lippi M, Roberts N, Mercuri AM.
Palynology and Mediterranean vegetation history. Flora Mediterranea [Internet]. 2013;23:141 - 156.
Publisher's VersionAbstractThe history of Mediterranean vegetation can be outlined using pollen grains contained in lacustrine, marine and other sediments. These sediments have recorded very important vegetation changes during recent geological times. For example, during the last 6 Ma (million years), the effects of different events acting at regional (e.g. the Messinian salinity crisis between 5.96 Ma and 5.33 Ma) and global (expansion of the Arctic ice at ca 2.6 Ma) scales produced a progressive decrease and final disappearance of tropical and subtropical taxa. However, prior to the start of the Quaternary the Mediterranean flora still included a consistent number of tropical and subtropical arboreal taxa accompanying deciduous and partly evergreen trees that have persisted until today. The most important features of the vegetation history of the Quaternary consist in the fact that vegetation adapted to climate changes due to changes in orbital cyclicity, alternating between glacial and interglacial periods. The more widespread vegetation types were steppe and grassland formations during the dry and cold glacial periods whereas either deciduous or evergreen forests were characteristic of interglacial periods. These cold-dry to warmhumid climate cycles became more and more intense towards the present. During the second half of the present interglacial, after the mid-Holocene, joint actions of increasing dryness, climate oscillations and human impact led to the present day Mediterranean plant landscape. It is however not clear how far the causation of this spread of evergreen taxa was climatic or human. One of the most exciting challenges is the prediction of the future course of Mediterranean vegetation. In this perspective a consistent help, not fully explored yet, can be found in aeropalynology, recording the pollen transported in the air. Together with modern surface samples, these data act as modern analogues. Though it probably does not represent the same past vegetational composition, the current pollen rain is the only basic reference on which our comparative approach can rely. Present trends are interpreted and future scenarios can be hypothesized just using a combination of aero- and archaeo-/palaeo-palynological approaches.
2012
Hayden B, Bassiakos I, Sarris A, Zacharias N, Pavlopoulos K, Theodorakopoulou K, Athanassas K, Triantaphyllou MV, Kouli K, Tsourou T, et al. An interdisciplinary approach of the palaeoenvironment and cultural remains of Istron, Mirabello Bay, E. Crete. 5th Symposium of the Hellenic Archaeometry Society. 2012:327-344.
Kouli K, Gogou A, Bouloubassi I, Triantaphyllou MV, Ioakim C, Katsouras G, Roussakis G, Lykousis V.
Late postglacial paleoenvironmental change in the northeastern Mediterranean region: Combined palynological and molecular biomarker evidence. Quaternary International [Internet]. 2012;261:118 - 127.
Publisher's VersionAbstractThree gravity cores collected from the NE Mediterranean (NEMR) across a transect from the northern Aegean Sea (North Skyros basin) to the south Cretan margin (SCM), were investigated for pollen and terrestrial biomarkers derived from epicuticular waxes of vascular plants during the last ~20 ky. Pollen data show diversified mixed temperate forest in the northern borderlands and enhanced Mediterranean vegetation in the southern areas, documenting an N-S climatic trend. Terrestrial plant biomarkers and their diagnostic geochemical indices exhibit latitudinal patterns which are interpreted in terms of the different delivery pathways (fluvial/runoff vs. atmospheric transport), resulting from the climate conditions during different periods. During the Late Glacial and early deglaciation periods (20-14 ka BP) relatively increased humidity (H-index) is recorded in the north Aegean Sea, while in the South drier climate was the limiting factor for vegetation development. During this interval, terrestrial n-alkanes showed increased accumulation rates, suggesting massive transport of terrestrial organic matter through runoffs and rivers, followed by weaker input after 14 ka BP. After ~11 ka BP a major expansion of forest cover is evidenced in the NEMR, accompanied by a higher H-index because of the climatic amelioration. The forest vegetation exhibited regionally different characteristics, with cool temperate taxa being more abundant in the Aegean cores, while the SCM record is being featured by Mediterranean elements. At the onset of the Holocene and throughout the Holocene Climatic Optimum the delivery of terrestrial biomarkers increased and became more significant in the Aegean sites compared to the SCM site. Within the Holocene, the average chain length (ACL) of long chain n-alkanes exhibits lower values in the northern Aegean than in the southeastern Aegean and SCM, indicating the predominance of warmer species southwards. Finally, the H-index records a conspicuous humidity increase between 5.4 and 4.3 ka BP in the south Aegean that coincides with an increase in the terrestrial biomarker supply and the deposition of a distinct sapropel-like layer, SMH (Sapropel Mid Holocene). Similar trends in T (temperature) and H indices are slightly delayed and attenuated in the northern Aegean and are accompanied by an increase in the ACL index. A noticeable increase in the accumulation rates (ARs) of terrestrial biomarkers and the HPA index values during this period are clearly recorded in all three cores, indicative of enhanced terrigenous inputs of organic matter along with higher in-situ preservation.
Kouli K.
Vegetation development and human activities in Attiki (SE Greece) during the last 5,000 years. Vegetation History and Archaeobotany [Internet]. 2012;21(4-5):267 - 278.
Publisher's VersionAbstractPollen assemblages recovered from a 5 m sediment core from the Vravron coastal marsh suggest a close correlation between vegetation development and human presence in Attica, and provide the first complete record of middle to late Holocene vegetation history. Correlation of pollen with archaeological data attempts to decode the man–environment relations of the past, within the context of the known climatic variability of the mid late Holocene, in the vicinity of ancient Athens, an area of high historical significance. The pollen record of Vravron denotes a rather variable landscape where open Mediterranean evergreen pine woods alternated with maquis shrublands and grasslands, where human activities and climate have left their imprints on vegetation. During the last 5,000 years agricultural practices displayed several variations: cereal cultivation appears more intense during the Bronze Age, especially in the Mycenaean, while a spread of Olea is observed during Geometric to Classical times. The gradual abandonment of Olea cultivation evidenced in our pollen diagram came as a result of the displacement of human activities in the interior of Mesogaia in Hellenistic and Roman times. Olea and cereal cultivation intensification is observed again during the Mesobyzantine period. In the upper part of the core evidence of intense soil erosion and expansion of Vravron wetland was recorded, coinciding with the Little Ice Age climatic event and the introduction of Arvanites populations in the area.
2011
Bouloubassi I, Gogou A, Triantaphyllou M, Katsouras G, Kouli K, Roussakis G, Likousis V.
Holocene Centenial-scale paleoceanographic and paleoenvironmental patterns in the NE Mediterranean sea. In: PP51C-1852 AGU Conference. San Francisco, USA; 2011.
Publisher's VersionAbstractThe Eastern Mediterranean Sea lies in a climatological transition zone, under the influence of both tropical and mid-latitude climate processes. Within this basin, the Aegean Sea has been recognized as a highly sensitive area to global/regional climate change. Sediment archives provide robust evidence for changes in its hydrological properties and biogeochemical functioning as a response to past climate variability. In order to investigate the region's paleoclimatic and paleoceanographic patterns during the Holocene, with a special emphasis on the sapropel S1 interval, we have investigated marine sediment cores along a N-S transect in the Aegean and the S. Cretan Seas. We focus on combined geochemical, micropaleontological and palynological proxies, namely organic biomarkers, organic carbon and nitrogen stable isotopes, coccolithophore and pollen assemblages, aiming at reconstructing climate-related parameters such as sea surface temperature (SST), marine productivity patterns, stratification and nutricline fluctuations, continental vegetation patterns and land-sea interactions. SST patterns depict major global/regional climate fluctuations during the last glacial and deglaciation periods, depict the warm transition to the Holocene optimum, when the formation of the S1 sapropel takes place, a distinct cool episode around 8 ka BP (coeval with the S1 interruption), a conspicuous mid-Holocene warm phase (5.4-4.3 ka BP) as well as other distinct fluctuations. Diagnostic marine lipids, δ15N, and coccolithophore assemblages allow documenting the variability of primary productivity and associated organic carbon accumulation in sediments, as well as fluctuations in water column stratification and nutricline, especially during the deposition of the S1 sapropel. Combined terrigenous proxies record warm/cool and dry/humid time intervals, allowing land-sea correlations, and document changes in the delivery of terrestrial material to the sea related to climate-driven fluctuations in freshwater discharges. The network of sediment cores studied provide a better constrain of the regional climate patterns in the northeastern Mediterranean Sea and enables assessing potential time lags and gradients.
Karkanas P, Pavlopoulos K, Kouli K, Ntinou M, Tsartsidou G, Facorellis Y, Tsourou T.
Palaeoenvironments and site formation processes at the Neolithic lakeside settlement of Dispilio, Kastoria, Northern Greece. Geoarchaeology [Internet]. 2011;26(1):83 - 117.
Publisher's VersionAbstractDispilio is a lakeside settlement by the Orestias Lake, Kastoria, northern Greece. The site was inhabited from the Middle Neolithic to the Chalcolithic, with some surface evidence of Bronze Age occupation. Microfacies analysis of the sediments, supported by a suite of environmental indices, has provided detailed paleoenvironmental data and elucidated the main processes involved in the formation of the site and its history of occupation. The settlement was established on the lakeshore, on a shallow sand ridge and a shore marsh. Initially, houses were built on raised platforms above the water. After a major conflagration, a range of depositional microenvironments were established that caused local changes in the sedimentation rate. Therefore, some areas quickly emerged and became dry land, while some others continued to be flooded as part of the transitional supra-littoral environment. On the dry land, houses were built directly on the ground, whereas in the transitional areas houses continued to be built on raised platforms. Thus, gradually, a mound was formed and further shaped by subsequent lake-level fluctuations. One of the lake-level rises is tentatively related to the abandonment of the mound in the Chalcolithic and the development of a hardpan on its surface. There is also evidence of later occupation during the Bronze Age in the form of a few, mostly surface, archaeological remains.
2010
Pavlopoulos K, Kouli K.
Paleogeography, climate and vegetation in Western Macedonia plain. In: Aggelochori Imathias: a Late Bronze Age settlement. L. Stefani (ed). Kyriakidis Brothers Publ; 2010.
Abstract
Kouli K.
The vegetation during Late Bronze Age: pollen analysis results. In: Aggelochori Imathias: a Late Bronze Age settlement. L. Stefani (ed). Kyriakidis Brothers Publ; 2010. pp. 45-49 .
Triantaphyllou MV, Kouli K, Tsourou T, Koukousioura O, Pavlopoulos K, Dermitzakis MD.
Paleoenvironmental changes since 3000 BC in the coastal marsh of Vravron (Attica, SE Greece). Quaternary International [Internet]. 2010;216(1-2):14 - 22.
Publisher's VersionAbstractThe coastal area of the Vravron Bay, in the vicinity of the homonym archaeological site, is a marshy plain located on the eastern part of the Attica Peninsula (eastern Greece). In order to provide evidence for palaeoenvironmental changes and landscape evolution of the area, detailed micropaleontological, palynological and sedimentological analyses have been conducted at the underlying Late Holocene coastal deposits. The recovered sediments (lithostratigraphic Units A–D) represent a continuous record of the environmental history of the area since the Early Bronze Age, covering all subsequent historical periods. The base of the recovered deposits is older than the 3rd millennium BC. Until late medieval times, the studied sequence contains plenty evidence for the existence of the natural port reported from the Mycenaean (lithostratigraphic Unit A), that infilled after repeated flooding events during the Classic period (lithostratigraphic Unit B) and gradually developed into a shallower marine environment (lithostratigraphic Unit C). In the uppermost part of the sequence (lithostratigraphic unit D), a transition towards brackish environment with intense fresh water input is featured around 1540 AD. Signs of human agricultural activities in Vravron appear since 3000 BC (Early Bronze Age) and are linked to the history of inhabitation in the area.
Pavlopoulos K, Triantaphyllou M, Karkanas P, Kouli K, Syrides G, Vouvalidis K, Palyvos N, Tsourou T.
Paleoenvironmental evolution and prehistoric human environment, in the embayment of Palamari (Skyros Island, Greece) during Middle-Late Holocene. Quaternary International [Internet]. 2010;216(1-2):41 - 53.
Publisher's VersionAbstractPalamari Bay is located on the northeastern coast of Skyros Island (Sporades Islands, Aegean Sea). At the northern edge of the bay a fortified prehistoric settlement is found, dated between 2800 and 1700 BC (Early Bronze Age II–Middle Bronze Age I). Detailed geomorphological mapping of the coastal alluvial plain and paleontological, micropaleontological, palynological, sedimentological and micromorphological studies of the Holocene coastal deposits have been conducted in order to reconstruct the palaeoenvironment and the landscape evolution of the broader area of Palamari Bay. Three main sedimentary units were recognized (A, B and C, from oldest to youngest). The lowermost sedimentary unit A, deposited between before 7500 and 3500 cal BP, consists of sediment deposited from high to moderate energy fresh water flows with some suspended load fallout in established water bodies. The microfauna indicates a shallow fresh water environment. However, a tendency to oligohaline conditions was established gradually. During the same period, the Palamari area was characterized by open mixed deciduous forests that gradually retreated as a possible consequence of the intensification of anthropic activity, associated with the settlement of Palamari. Indications of cultivating and grazing activities in the vicinity of the lagoon were identified, pointing to a strong human presence since the Neolithic. Between about 6000 and 3500 cal BP, the embayment was a lagoon southeasterly connected to the sea, therefore sheltered and protected from northeastern winds. The overlying unit B (ca. 3500–800 cal BP) is characterized by the dominance of brackish water microfauna, indicating a brackish stagnant shallow water depositional environment, which was periodically supplied with fresh water from the surrounding springs. As the result of the continuous sea-level rise during the Late Holocene, part of the northern headland was submerged. The decline of the Palamari settlement at the time of the establishment of Unit B might be related to the observed changes that rendered the embayment a restricted body of water. The uppermost sedimentary unit C corresponds to a backshore environment dominated by aeolian activity modified by fluvial processes.
2001
Kouli K, Brinkhuis H, Dale B.
Spiniferites cruciformis: A fresh water dinoflagellate cyst?. Review of Palaeobotany and Palynology [Internet]. 2001;113(4):273 - 286.
Publisher's VersionAbstractPalynological studies of cored lacustrine sediments from the late Quaternary of Lake Kastoria, northern Greece, revealed a Late Glacial interval with abundant dinoflagellate cysts. Cyst assemblages include two identifiable species, Spiniferites cruciformis and Gonyaulax apiculata. The presence of the fresh water species G. apiculata is consistent with the lacustrine setting of these deposits, but that of S. cruciformis is anomalous. Previously, this species has only been recorded in abundance from presumed brackish marine sediments from the Black Sea and Marmara Sea sediments where geochemical data clearly record brackish salinities. Therefore, it has been regarded as a low salinity cyst type with a wide range of morphological variation that some workers have suggested to reflect salinity fluctuations. Specimens from Greece display only part of the range of morphological variability previously described from these (brackish) marine settings. Encountered morphological variation includes ellipsoidal/pentameral and cruciform endocyst shapes with rare intermediate shapes, and highly variable septa development. Specimens characterized by extremely reduced ornamentation known from (brackish) marine environments have not been recorded. Our records of S. cruciformis indicate that: (1) it could thrive in fresh water conditions; and (2) that apparently most of the strong morphological variations of the cysts are an intrinsic phenomenon for this taxon, and may only partly be linked to salinity variations as suggested earlier. We suggest that S. cruciformis essentially is a fresh water taxon, and that its records in (brackish) marine environments, with the exception of specimens with strongly reduced ornamentation, may be due to transportation, to short-lived fresh water surface conditions in such environments, or to tolerance of the species to brackish conditions.