Figure 7 - uploaded by Simon Connor
Content may be subject to copyright.
Source publication
This dissertation presents new data on the vegetation history of the Caucasus,
a region of high biodiversity and ancient human occupation. The aim of the study is
to determine the causes of vegetation changes in Southern Georgia over the past
14,000 years by comparing well-dated pollen and charcoal records to evidence of past
climatic change and hu...
Similar publications
The surveys and excavations carried out in the highland zone of the Grevena Pindus Mountains have revealed that the watershed that separates western Macedonia from Epirus was (seasonally) inhabited in different prehistoric times, from the Middle Palaeolithic to the Bronze Age. The highest concentration of 'sites' is known from the surroundings of t...
Citations
... Geomorphological studies have indicated that during the Pleistocene the snowline of the Alborz Mountains was 600 to 1100 or even 1800 m lower than at present (Bobek, 1963;Krinsley, 1970;Ferrigno, 1991). Similar to north-central Iran, the colder-and drier-than-present climate of GS-2 in the Caucasus region significantly influenced the altitudinal distribution of forest vegetation, and coniferous forests and broadleaved trees were confined to the lowlands of the west Georgian Black Sea area and the east Georgian floodplains (Connor, 2011;Shatilova et al., 2011). ...
... A dry and cold phase is also indicated by palynological studies from southern Georgia (Connor, 2011). Connor (2011), however, argues that the continental interiors of the Caucasus and adjacent regions experienced "extreme seasonality" rather than hyper-aridity. In the eastern Mediterranean regions GS-I is normally hardly discernible in pollen diagrams because in the dry areas the vegetation was already open during the previous warm interstadial (Bottema, 1995). ...
... We assume that the prominent climatic dryness at this interval was a major cause for the succession from lake to peatland. Fig. 9. Comparison of major AP and NAP curves in PHL (this study) with other long pollen records from the southern Black Sea (Shumilovskikh et al., 2012), Georgia (Connor, 2011;Connor et al., 2017) and a pollen record from Central Europe (Rösch, 1990). E. ca. 12, ...
The Hyrcanian region is a biogeographic entity of high biodiversity and a centre of Arcto-Tertiary relict flora. A pollen record from the mid-elevation of the Alborz Mountains (northern Iran) reaching back to 20,000 cal BP
reveals the Late Quaternary vegetation history of this globally important forest ecosystem. For the period
20,000–14,419 cal BP the pollen record indicates the presence of beech, oak, and birch associated with elm and
hornbeam, which indicates the presence of a Weichselian refugium for deciduous tree species. The simultaneous
presence of abundant pollen attributable to Artemisia, Amaranthaceae, Apiaceae, and Hippopha¨e rhamnoides
suggests the presence of a dry and cold steppe environment at higher elevations. For the period 16,746–14,419
cal BP, the pollen record indicates a steppe vegetation around the studied peatland (with a predominance of
Artemisia, Amaranthaceae and Apiaceae species, along with Eremurus), a slight expansion of oak, and a strong
decrease of beech. The period 14,419–12,993 cal BP started with a substantial rise in the values of pollen
attributable to Quercus, Carpinus, and Ulmus with the near absence of pollen of dry-growing herbaceous vegetation.
For 12,993–11,745 cal BP, a drastic decline of arboreal pollen types, pronounced peaks of NAP types, and
constant values of pollen of Ephedra persuasively point to a dry period in the studied region. Towards the end of
this period, when the climate apparently became somewhat warmer, deciduous trees expanded around the study
site earlier than in other regions, probably because of the site’s proximity to the refugium. After 8600 cal BP, oak
declined in importance whereas beech and hornbeam expanded, showing the establishment of the contemporary
temperate climate and vegetation. A pronounced expansion of alder and wingnut took place around 4000 cal BP.
A remarkable decline of Pterocarya pollen at 1060 cal BP may relate to human impact and/or a cooling/drying
climate.
... The need for harmonisation becomes increasingly important when pollen-analytical data from many sequences in a geographical area are combined, synthesised, and compared. The extent of the geographical area may range from a single valley (e.g., Birks, 2007) to a large island (e.g., Birks, 1973), a landform unit (e.g., Walker, 1966), a state (e.g., Cushing, 1963), part of a country (e.g., Connor, 2011;Tonkov, 2021;Woodbridge et al., 2023), an entire country (e.g., Fredskild, 1973), a biome or a major climate zone (e.g., Cruz-Silva et al., 2023; Liu et al., 2020;Liu et al., 2023), part of a continent (e.g., Cao et al., 2013;Cao et al., 2020;Seddon et al., 2015), an entire continent (e.g., Giesecke et al., 2019;Githumbi et al., 2022;Huntley, 1990;Huntley and Birks, 1983;Mottl et al., 2021;Phelps et al., 2020;Trondman et al., 2015;Williams and Shuman, 2008), a hemisphere (Cao et al., 2019), or the Earth (Herzschuh et al., 2021;Herzschuh et al., 2022). Harmonisation seeks to find a pollen taxonomic level to which all the pollen of a particular plant taxon (or taxa) have been consistently determined in all the sequences within the geographical area of study and to give an unambiguous and appropriate name to that morphotype . ...
... It also grows sporadically in the margins of mires up to 1400 m asl (as is the case at the KHL site). A rather well-defined Pterocarya decline has been registered for the periods 1000-800 cal BP in pollen diagrams from central-northern Iran (Khakpour Saeej et al., 2014;Ramezani et al., 2008Ramezani et al., , 2016Ramezani, 2013), the south-eastern Caspian Sea lowlands (Leroy et al., 2013), and western Georgia (Connor et al., 2007;De Klerk et al., 2009;Kvavadze, 1982in Connor, 2011. For unknown reasons, the decline in the KHL record is delayed by ca. ...
... In addition, these sedimentary archives record part of the long-distance pollen signal. This signal echoes the evolution of the diversity and structuring of the vegetation of the North of the Lesser Caucasus (Zarishat, Shenkani, and in Georgia: Tsavkisi, Connor, 2006;Jvari, Connor et al., 2020;Paravani, Connor and Kvavadze, 2009;Messager et al., 2013) and the East (this study, Vanevan). ...
Pollen-based vegetation change has been inferred from sediments in Kalavan Red Lake. This small lake is placed in the beech-oak-hornbeam forest, about three kilometres away from archaeological remains. It has the potential to document the Holocene forest history and climate and human impacts on the Lesser Caucasus. However, this lake happens to be formed by a large landslide.
Pollen and XRF analysis are provided over the last 3800 years. The basal age of the Kalavan sediment approximates the landslide age. This created a not vegetated slope including the lake catchment. Erosion and sedimentation processes brought coarse and heavy minerogenic elements, declining with the catchment revegetation by tall-grassland. This shift in the sedimentation continues, suggesting less erosion in the catchment when an admixture of Quercus and grasslands settled. Starting from 2000 cal. BP, arboreal pollen increases successively thanks to the step afforestation of Quercus, Carpinus orientalis and Fagus.
The comparison with available pollen reconstruction illustrates the uniqueness of the vegetation dynamic recorded at Kalavan. However, the duration of this succession is also questionable. An intermediate hypothesis is proposed: the Kalavan's dynamic is first initiated by the landslide with the tall-grass development, then paced by the regional vegetation dynamic.
Linking vegetation history and erosion with regional climate and archaeological data helps to evidence short-term climate change and human impact. Antique arid phase (2000–1600 cal. BP), the Medieval Warm Period and Little Ice Age affect the vegetation, while demography variations during the Medieval period and Modern Age are shown by pastoral activity.
... If located in the wetland, a drainage system would have been required in conjunction with fire utilization to suppress semi-aquatic vegetation. At this period, increase of fire activity is recorded in Armenia (Joannin et al., 2014;Cromartie et al., 2020) and Georgia (Connor, 2011). This period is also consistent with the conquest of Alexander the Great in 2281 a cal BP (Briant, 1996) and the foundation of the Kingdom of Armenia, which contributed to a change of human practices. ...
... During this period, open vegetation is also recorded in the Southern Caucasus and the Near East mainly, although the dominant steppic taxa varies from (1) Poaceae (this study; Roberts et al., 2001;Stevens et al., 2001;Wick et al., 2003;Stevens et al., 2006;Ryabogina et al., 2018;Cromartie et al., 2020), to (2) Artemisia (Djamali et al., 2008;Joannin et al., 2014;also in Central Asia: Chen et al., 2008;Zhao et al., , 2020, or (3) Chenopodiaceae (Leroy et al., 2013;Messager et al., 2013). In contrast, the sites north-west of Armenia document forested phases during the same part of the Early Holocene (Connor, 2011;Shumilovskikh et al., 2012;Messager et al., 2017;Connor et al., 2018;Grachev et al., 2020). At Vanevan, a low proportion of arboreal pollen taxa is recorded (Fig. 7). ...
... At Vanevan, the vegetation changes around 5100 a cal BP can be discussed in light of the presence of important fires (detected by macro-charcoals) that have affected the landscape and the wetland itself (Leroyer et al., 2016). Several hypotheses explain the ignition of fires: (1) an anthropogenic cause with the lighting of fires by the local population living around Gilli wetland; (2) a volcanic origin due to nearby lava flows from Porak volcano dated to the Mid-Holocene (Fig. 1C, Karakhanian et al., 2017;Meliksetian et al., 2021) or (3) a climatic driver linked with the aridification period around 5000 a cal BP recorded in Armenia (Joannin et al., 2014), Georgia (Connor and Kvadadze, 2008;Connor, 2011), Turkey , Iran (Stevens et al., 2001(Stevens et al., , 2006 and in Israel ( Bar-Matthews et al., 1997). Although this event could be multifactorial, the regional scale of the changes points towards a climatic cause. ...
Relationships between steppe vegetation, human practices and climate changes in the past are crucial to disentangle human development in Eurasia. In this frame, our study investigates (1) modern pollen-vegetation relationships and (2) changes in vegetation, human activity and climate in the Holocene record of Vanevan peat (south-eastern shore of Lake Sevan, Armenia), using a multiproxy approach including sediment geochemistry (XRF), pollen, Non-Pollen Palynomorphs (NPPs), and branched Glycerol Dialkyl Glycerol Tetraethers (brGDGTs). Climate reconstructions are provided by (1) water-level changes, (2) brGDGTs, and (3) pollen transfer functions (multi-method approach: Modern Analogue Technique, Weighted Averaging Partial Least Squares regression, Random Forest, and Boosted Regression Trees). Modern pollen assemblages are selected along an altitudinal transect in Armenia. They show a dominance of Chenopodiaceae in semi-desert/steppe regions while meadows steppes, subalpine, and alpine meadows are dominated by Poaceae. Past vegetation is characterized by steppes dominated by Poaceae surrounded during the Mid-Holocene (8200–4200 a cal BP) by scarce open woodlands. Humans have influenced the local vegetation, mainly through their agricultural practices present since 5200 a cal BP with several intensification steps. Our reconstruction indicates a climate shift from a cold and arid Early Holocene toward a warmer and more humid Mid-Late Holocene. An aridification trend marks the last 5000 years causing a drop in water level, which allowed humans to live and cultivate on Lake Sevan shores. Arid events are recorded at 6.2 ka, 5.2 ka, 4.2 ka and 2.8 ka a cal BP, which are commonly related to multi-centennial-scale variations of Westerlies activity (North Atlantic Oscillation). Through our temperature reconstruction, we can assign (1) the 5.2 and 2.8 ka events as being cold and probably related to a strong Siberian High, and (2) the 4.2 ka event as being warm associated with high Arabian subtropical pressures in the South Caucasus and the Near East. Our study suggests a significant impact of these arid events on the Lake Sevan shore populations and they are consistent with cultural phases in the South Caucasus, thus showing the impact of climatic variations on cultural, land use and occupation mode development in this crossroad region between Europe, Africa and Asia.
... Generally, the reconstructed vegetation in the Caucasus from the Early Holocene, beyond the Colchis Lowland, indicates a domination of treeless landscape and delayed expansion of forests in comparison to Europe due to spring dryness that occurred in that period 65,66 . At some locations, a high level of Pinus pollen dated to the Late Pleistocene is reported and could indicate a local presence of the species outside the major Pontic Mts.-Adjara refugium 64 . ...
... Recently, the Holocene fragmentation was demonstrated as the significant factor shaping the spatial genetic structure in P. nigra in Europe 69 . The pollen records from the Caucasus suggest that the Early Holocene was climatically adverse to Scots pine and to other conifers, leading to a reduction in their abundance in the region 64 . In this period the upward migration of Scots pine probably occurred in response to warming noted in the Caucasus. ...
... This likely contributed to further fragmentation and genetic differentiation due to reduced gene flow in a complex mountainous landscape. Additionally, Scots pine is less competitive in comparison to other conifers growing in the Caucasus which could also 64 . Similar to other conifers, the species reached its maximum abundance just ca. ...
Scots pine is one of the most widely occurring pines, but future projections suggest a large reduction in its range, mostly at the southern European limits. A significant part of its range is located in the Caucasus, a global hot-spot of diversity. Pine forests are an important reservoir of biodiversity and endemism in this region. We explored demographic and biogeographical processes that shaped the genetic diversity of Scots pine in the Caucasus ecoregion and its probable future distribution under different climate scenarios. We found that the high genetic variability of the Caucasian populations mirrors a complex glacial and postglacial history that had a unique evolutionary trajectory compared to the main range in Europe. Scots pine currently grows under a broad spectrum of climatic conditions in the Caucasus, which implies high adaptive potential in the past. However, the current genetic resources of Scots pine are under high pressure from climate change. From our predictions, over 90% of the current distribution of Scots pine may be lost in this century. By threatening the stability of the forest ecosystems, this would dramatically affect the biodiversity of the Caucasus hot-spot.
... For Georgia, e.g.,Connor 2006; Kvavadze et al. 2020. 3 A.o.,Connor et al. 2004;Connor, Sagona 2007;Connor, Kvavadze 2009, 2014 ...
The paper discusses the malacological remains recovered at Khashuri Natsargora and Aradetis Orgora, two Bronze Age/Iron Age sites located in the Kura River basin of the
Shida Kartli province of Georgia (Southern Caucasus). The corpus consists of over 500 items, which include both land and (especially for Aradetis Orgora) freshwater species, while marine species represent an extremely marginal portion of the total. The record, obtained through direct collection during the excavation, included only the species with the largest and most resistant shell (therefore better recognisable with the naked eye),
and represents only a part of the malacological assemblages relevant to the investigated stratigraphic sequences. Despite these objective limits, it was considered appropriate to present the collected data and the results of their analysis, as they allowed to obtain some paleoecological and paleoeconomic information that is not totally devoid of interest. The analysis on the available remains shows a clear dominance of species
connected with open and xeric environments, in substantial agreement both with the present local environment and with the few available palaeoenvironmental data. The very
weak diachronic variability of the assemblages seems to suggest a substantial ecological stability for both biotopes. The abundance of freshwater molluscs at Aradetis Orgora
can be explained with the proximinity of the site to the Prone and Kura rivers, biotopes from which they may have been intentionally collected for use as food, as some parallels from other Bronze Age societies may suggest.
... A relationship between the two major zonal forest communities of the studied region, Oriental beech and oak-hornbeam forests (Bohn et al. 2000(Bohn et al. -2003, requires further research. Their distributions were most likely influenced by human interventions lasting here at least four millennia (Conor 2006). Traditional forests management, still locally practised, generally favours oak-hornbeam forests at the expense of beech forests (Bradshaw et al. 2010;Leuschner and Ellenberg 2017). ...
The Caucasus harbours unique forest vegetation so far only little studied using the Braun-Blanquet approach. This study is mostly based on a dataset (N = 110) of original phytosociological relevés of oak-hornbeam and ravine forests in the Eastern Greater Caucasus, Georgia. Their unsupervised classification produced seven communities. Five belong to oak-hornbeam forests (order Lathyro-Carpinetalia caucasicae). Of the zonal Caucasian alliance Crataego-Carpinion, the association Corno australis-Carpinetum inhabits valleys of the Greater Caucasus, and Clinopodio umbrosi-Carpinetum is confined to the warm Eastern Greater Caucasus promontories. The association Astrantio maximae-Carpinetum of the alliance Astrantio-Carpinion represents distinctive Caucasian montaneoak-hornbeam forests. The other two communities, documented by a few relevés, were described at the community level only. Within ravine forests (order Aceretalia pseudoplatani), we introduce a new Caucasian alliance Pachyphragmo macrophyllae-Tilion begoniifoliae with two associations. Valeriano tiliifoliae-Ulmetum glabrae comprises Caucasian montane ravine forests whereas Hedero pastuchovii-Aceretum velutini inhabits the foothills of the Eastern Greater Caucasian. To provide a broader context of the recognized communities, an expanded dataset (N = 231) of original relevés and previously published relevés of Georgian deciduous forests was analysed. It indicated a major turnover in species composition following biogeographical patterns presumably driven by macroclimate and vegetation history.
... Human activity is well-documented in records of Holocene landscapes throughout the South Caucasus (Connor, 2011;Messager et al., 2013;Joannin et al., 2014) and greater southwest Asia (Djamali et al., 2009;Roberts et al., 2011;Woodbridge et al., 2019). In the Caucasus, early cereal farming and sheep/goat pastoralism date to the sixth millennium cal. ...
... Volodicheva, 2002;Nakhutsrishvili, 2013, also see Connor, 2011 for discussion). Records from Georgia (Connor, 2011) and Armenia (Zarishat: Joannin et al., 2014;Vanevan: Leroyer et al., 2016) have challenged these narratives. They demonstrate the dominance of steppe taxa prior to the introduction of permanent settlements and agricultural practices. ...
... In the Caucasus, select Poaceae species can grow on the wetland itself, increasing Poaceae's signal. This was discussed in relation to sequences from Vanevan, Armenia (Leroyer et al., 2016), and in Georgia (Connor, 2011). The transition from Chenopodiaceae to Poaceae occurs at different timings than wetland transitions, with the spread of Poaceae occurring at 9500 cal. ...
... Therefore in the published pollen diagrams the mention is made only for Vitis genera and not for the species. Nevertheless, technological and methodological advances during the last 15 years have allowed the identification of distinctive features of Vitis vinifera pollen grains, allowing for its documentaion in an entire series of recent publications (Turner and Brown 2004;Babaev et al. 2009;Shatilova et al. 2011;Bitadze et al. 2011;Connor 2011;Chichinadze et al. 2012Chichinadze et al. , 2017Chichinadze et al. , 2019Langgut et al. 2013;McGovern et al. 2017;Maghradze et al. 2018, Maghradze et al. 2019, Kvavadze et al. 2008, Kvavadze et al. 2013, Kvavadze et al. 2015, Kvavadze et al. 2020). The earliest pollen evidence of Vitis belongs to the Pleistocene era (Cârciumaru 1985), but no absolute chronology is available. ...
This paper reviews the, so far available, paleorecords of Vitis sylvestris C.C. Gmel and Vitis vinifera L. from Romania. The study takes into consideration the presence of Vitis pollen from Holocene peat sediment sequences and archaeological context, but also the presence of macrorests from various archaeological sites that date from Neolithic, Chalcolithic, Bronze Age, and La Tène. Both paleobotanical arguments and archaeological discoveries support the theory that places the beggining of viticulture in Romania a few millenia ago, in Neolithic period. Also, written evidences (works of classical authors, epigraphical sources) confirm, indirectly, the presence of grapevine in La Tène period. Occurrences of Vitis vinifera and those of Vitis sylvestris manifest independently of the climate oscillations, being present both through colder and more humid episodes, as well as through drier and warmer events. Probably prehistoric communities have made a constant and deliberate effort, all along the Holocene, to maintain grapevine crops.
