Climate deterioration and land-use change in the first millennium BC: perspectives from the British palynological record

Climate deterioration at around the time of the Bronze Age/Iron Age transition has for long been argued to have resulted in upland abandonment in northern and western Britain, and recent research has provided evidence that a major climate downturn from 850 cal BC caused settlement abandonment in western Europe and potentially worldwide. It is, however, unclear to what extent only ‘marginal’ sites were affected, due to the lack of any systematic attempt to view the evidence for settlement and land-use change across a range of landscape types with differing sensitivities to environmental change. This paper addresses this issue by an evaluation of 75 pollen sequences spanning the late Bronze Age and early Iron Age in Britain to assess whether climatic deterioration was sufficient to cause widespread land abandonment. The results provide no evidence for wholesale land-use change at this time; the overall picture is one of continuity of land use or even increased agricultural activity. There are, however, hints of regional variability, with a greater tendency to abandonment of upland areas in Wales, and signs of woodland regeneration in agriculturally productive areas of lowland central southern England. The latter pattern may reflect a combination of rising ground-water levels affecting local land-use in the immediate vicinity of the mires which provide the source of the pollen data, against a backdrop of regional-scale social and economic changes at the Bronze Age-Iron Age transition.     

The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages

Between the 13th and 11th centuries BCE, most Greek Bronze Age Palatial centers were destroyed and/or abandoned. The following centuries were typified by low population levels. Data from oxygen-isotope speleothems, stable carbon isotopes, alkenone-derived sea surface temperatures, and changes in warm-species dinocysts and formanifera in the Mediterranean indicate that the Early Iron Age was more arid than the preceding Bronze Age. A sharp increase in Northern Hemisphere temperatures preceded the collapse of Palatial centers, a sharp decrease occurred during their abandonment. Mediterranean Sea surface temperatures cooled rapidly during the Late Bronze Age, limiting freshwater flux into the atmosphere and thus reducing precipitation over land. These climatic changes could have affected Palatial centers that were dependent upon high levels of agricultural productivity. Declines in agricultural production would have made higher-density populations in Palatial centers unsustainable. The ‘Greek Dark Ages’ that followed occurred during prolonged arid conditions that lasted until the Roman Warm Period.     

Response to late Bronze Age climate change of farming communities in north east Scotland

Pollen analyses are presented spanning the Bronze and Iron Ages at two sites within one river catchment in north east Scotland, one upland and one lowland site, to test the hypothesis that subsistence agricultural communities relocated their activities in response to major climatic deterioration at the end of the Bronze Age. Such responses were identified, involving the probable cessation of arable farming around the upland site and increases in the intensity of anthropogenic impacts around the lowland site. These changes are consistent with a model that posits a restructuring of agricultural activities, but are not considered indicative of settlement abandonment in the face of climatic stress.     

Historical context and chronology of Bronze Age land enclosure on Dartmoor,UK

The upland of Dartmoor, southwest England, is one of the flagship prehistoric landscapes within Britain owing to the excellent survival of extensive prehistoric coaxial field systems. Archaeological surveys and rescue excavations during the 1970s and 1980s did much to further the understanding of this landscape; however, much remains to be explored, in particular the chronology of enclosure, the nature of the pre-enclosure landscape and the relationship between Bronze Age communities and their environment. Reconsideration of this landscape is important, given the place it holds in our understanding of subdivision of the landscape across northwest Europe during prehistory. This paper presents new palaeoecological data recovered as part of an integrated archaeological and palaeoecological project on northeast Dartmoor. The sequences detailed here include the first dated Neolithic period palaeoenvironmental data from within the prehistoric enclosed land on the moor, providing a longer-term context for enclosure. Neolithic groups are implicated in the first establishment of heathland in the study area at around 3630–3370 cal BC. During the early Bronze Age, reestablishment of hazel scrub in the study area implies reduced use of the upland, although it is not clear whether this is local or indicative of the wider landscape. A combination of pollen and fungal spore data indicates a substantial shift to species-rich grassland with grazing animals at c.1480 cal BC in a phase that lasted 400 years. The later Bronze Age and early Iron Age are characterised by low intensity use of the upland. These data provide new chronological data for land cover change on Dartmoor and whilst they broadly confirm existing models of upland land use in later prehistory, their proximity to the standing archaeology affords a more nuanced interpretation of local change.     

The Abandonment of the ZH-Mozartstrasse Early Bronze Age Lake-settlement. GIS Computer Simulation of the Lake-level Fluctuation Hypothesis

Although 'lake-dwellings' existed from the middle of the fifth millennium to the eighth century BC, the entire phenomenon was not a continuous one. There are several periods when the lake shores were abandoned and subsequently reoccupied. The pattern of occupation depends on cultural as well as environmental factors, amongst them the topography and the climate.
Unlike the southern part of the Alps, which seems to have had a more regular occupational pattern throughout the Neolithic and the Bronze Age, the northern Alpine region shows a marked discontinuity along most of the lake shores. Two relevant breaks in lake-shore occupation are known within the northern Alpine region Bronze Age. The first occurred between the 24th and the 20th centuries BC, and the second from the 15th to the middle of the 12th century BC.
The Early Bronze Age site of ZH-Mozartstrasse, situated on the western extreme of Lake Zurich (Switzerland), was abandoned immediately before the beginning of the second major occupational gap in 1503 BC. Two other Early Bronze Age sites namely Bodman-Schachen 1 on Lake Constance, and Arbon-Bleiche 2 on the Swiss part (the southern shore) of the same lake, follow a similar chronology in occupation; and they were both abandoned in the last decade of the 16th century BC.
A possible cause of abandonment is discussed in this paper using an environmental approach related to an abrupt change of climatic conditions which resulted in an increase of the lake levels which forced those prehistoric populations to leave the proximity of the lake shores. Following the implications of pollen and sedimental analyses, the transformation of the Bronze Age landscape caused by the lake water invasion will be simulated with the help of CAD and GIS computer programs.     

Mid- to late-Holocene vegetational and land-use change in the Hadrian's Wall region: a radiocarbon-dated pollen sequence from Crag Lough,Northumberland, England

Pollen, charcoal and sedimentological analyses of a radiocarbon-dated sediment sequence from Crag Lough, by Hadrian's Wall, northern England, are used to reconstruct vegetational and land-use change since ca. 3000 cal BC. Clearance of Quercus and Corylus avellana woodland began at ca. 2600 cal BC, followed by a substantial decline of Alnus glutinosa and spread of Calluna vulgaris at ca. 400 cal BC. Local cereal cultivation occurred sporadically from ca. 2200 cal BC, with a decline (perhaps associated with climatic deterioration) at ca. 900 cal BC, then an increase at ca. 600 cal BC. Secale cereale was grown in the area from approximately the first to fifth centuries AD, followed by a second phase from ca. AD 1250–1700, when it was accompanied by Cannabis sativa.The sequence is interpreted in the light of the archaeological record, particularly in relation to the impact of Roman military activity in the area. The most significant episodes of woodland clearance occurred in the late Neolithic/early Bronze Age period and then in the middle Iron Age, creating a patchwork of woodland, heather moorland, pasture and arable land by the Roman period. The main changes in the Roman period were a decline in the extent of Betula woodland and perhaps the local introduction of Secale cereale cultivation. Local land management practices involving fire seem to have been suspended in the Roman period, but resumed afterwards. The end of the Roman period may have been accompanied by a shift towards pastoral land-use and abandonment of less favourable agricultural land, but the effect was minor compared to that at other sites in the region. Later shifts in land use may relate to climate variability, as reconstructed from several mires in northern England.     

Abandonment of Minoan palaces on Crete in relation to the earthquake induced changes in groundwater supply

Mysterious abandonment of palaces on Crete during the Late Minoan period was always a challenging problem for archeologists and geologists. Various hypotheses explained this event by effects of tsunamis, earthquakes or climatic changes that were caused by the volcanic eruption of the Santorini volcano. While each of them or their possible combination contributed to the abandonment of palaces and following Late Minoan crisis, there is another possible cause that appeared as a result of studies within the last 20–30 years. This cause is depletion of groundwater supply caused by persistent earthquake activity that took place during the Bronze Age. This explanation is supported by field observations and numerous studies of similar phenomena in other locations.     

The little ice age in the Scottish Highlands and Islands: Documenting its human impact

This paper examines the Little Ice Age in the Scottish Highlands and Islands and uses documentary evidence to show its impact on the farm economy. It has three sections. The first examines how Highland climate may have changed during the Little Ice Age, and notes that increased storminess was probably as much a factor as lower annual mean temperatures. The second takes the most severe phase of the Little Ice Age, the Maunder Minimum, 1645–1715, and uses rests or eases of rent to show how it stressed the farm economy. The third examines evidence for the abandonment of land during the Maunder Minimum. As well as arguing that we need to see abandonment in its social as well as physical setting, it highlights the role played by the temporary abandonment of land and suggests that such abandonment along the western seaboard probably indicates the impact of increased storminess.     

Modelling of hydrology and potential population levels at Bronze Age Jawa,Northern Jordan: a Monte Carlo approach to cope with uncertainty

An annual water balance model for Wadi Rajil, in Northern Jordan, is used to simulate the ancient water supply system for the Early Bronze Age site of Jawa. The model includes: water delivery from the catchment; local pond storage; and water demand for people, animals and irrigation. A Monte Carlo approach is used to incorporate the uncertainty associated with a range of factors including rainfall, evaporation, water losses and use. The stochastic simulation provides estimates of potential population levels sustainable by the water supply system. Historical precipitation estimates from a Global Circulation Model, with uncertainty bounds, are used to reconstruct the climate at Jawa in the Early Bronze Age (EBA). Model results indicate that the population levels in the predicted wetter conditions during parts of the EBA could have risen to ∼6000 and may have been higher in wet years. However, palaeoclimatic proxies also suggest prolonged droughts in the EBA; and during these periods the water management system was unable to provide adequate supply for a population of 6000. The utility of Monte Carlo based hydrological modelling as a tool within archaeological science is discussed.     

Late quaternary alluviation and soil formation in the southern Argolid: its history,causes and archaeological implications

In the context of an archaeological survey of the southern Argolid, Greece, studies have been carried out to elucidate the evolution of the landscape since its earliest known human occupation about 50,000 years ago. One of these studies was a detailed geological mapping of the late Quaternary alluvium and soils in the area. Dated by means of thorium-uranium disequilibria, archaeological finds, and historical information, seven periods of alluviation were identified, each of short duration relative to long intervening periods of stability and soil formation. The three earliest alluvial phases, falling before and during the last glacial interval, range from about 330,000 to 32,000 years in age. No alluviation accompanied the last glacial maximum around 20,000 years ago. In fact, a stable landscape persisted until about 4500 years ago, when debris flows and widespread aggradation in the valleys resulted from major slope destabilization and soil erosion, probably as a result of extensive land clearance in the Early Bronze Age. A subsequent stable period lasted through the many upheavals of the later Bronze Age, the Dark Ages, and the early historical period. It came to an end with a brief phase of alluviation between about 300 and 50 BC. Stability returned through the late Roman period, notwithstanding considerable expansion of the settled area. Another period of destabilization, this one marked by debris flows and hence major soil erosion, is poorly fixed in time, but probably coincides with expanded maquis clearance accompanying the resettlement of the area around AD 1000. Subsequent events of soil erosion and aggradation vary in nature and timing from one drainage to the next and, in some areas, continue today.Nature and chronology of the soil forming and alluviation events show that simple correlations with climatic events do not suffice to explain them. For the latter ones, past about 2500 BC, human activity seems to be the dominant cause, but once again the relation between cause and effect is not straightforward. Land clearing, or neglect of soil conservation efforts during economic downturns, appear to have a more devastating effect upon the landscape than do intensive land use or total land abandonment.     

Environmental Archaeology of Prehistoric NW Crete

Abstract

The occurrence of Central European tree-types no longer growing on Crete indicates that Neolithic and Bronze Age climates were moister than at present. Of equal significance is the appearance of large quantities of olive pollen in Late Neolithic levels, suggesting the practice of olive cultivation. Early Bronze Age levels show a disappearance of some Central European tree pollen and an increase in Mediterranean tree types, suggesting that the climate became somewhat drier. The pollen findings are used along with other environmental and archaeological data to reconstruct landscapes for the Neolithic and Bronze Age of NW Crete.     

Cultural Response to Environmental Change in the Alpine Lacustrine Regions: The Displacement Model

Summary. Following an abrupt change in climatic conditions, the Middle Bronze Age northern Alpine lake‐dwellers were forced to abandon their settlements. As a result, the archaeological record shows a gap of occupation from the end of the sixteenth century to the beginning of the twelfth century BC. Where did those groups go during that period? Recent studies show that some Middle Bronze Age sites hitherto regarded as traditional dry‐land dwellings might represent constructions by former lacustrine people. Typological analyses of pottery assemblages and house structure remains found on these sites have made it possible to trace them back to an origin in the lacustrine tradition. The MBA lake‐dwelling occupational hiatus could finally be bridged and the process of cultural continuity reconstructed. The MBA lake‐dwellers certainly did not disappear; they just temporarily adapted to a drier environment until the lake shores became ‘safe’ again for re‐settlement.     

WINE, OIL AND THE DIALECTICS OF POWER IN BRONZE AGE CRETE: A REVIEW OF THE EVIDENCE

'Mediterranean polyculture'(the systematic exploitation of olives and vines in addition to cereals from the beginning of the Bronze Age) has been considered as one of the main factors which led to the development of palatial institutions in Bronze Age Crete and mainland Greece. This paper reviews all the available, direct archaeological evidence for olive and vine exploitation and oil and wine production and use from Bronze Age Crete (microbotanical, macrobotanical, artefactual, epigraphic), discussing at the same time their taphonomic, analytical and interpretative problems. It is suggested that, at present, there is no reliable direct archaeological evidence to substantiate the 'Mediterranean polyculture'model. More significantly, research on wine and oil, if disconnected from the discourse of subsistence and the cultural-evolutionary models such as that of subsistence-redistribution and viewed within the framework of the anthropology of consumption, can more fruitfully illuminate important issues related to the dialects of power such as establishment and legitimation of authority, exploitation of labour and factional competition.     

Cultural,Demographic and Environmental Dynamics of the Copper and Early Bronze Age in Iberia (3300–1500 BC): Towards an Interregional Multiproxy Comparison at the Time of the 4.2 ky BP Event

This paper presents the first comprehensive pan-Iberian overview of one of the major episodes of cultural change in later prehistoric Iberia, the Copper to Bronze Age transition (c. 2400–1900 BC), and assesses its relationship to the 4.2 ky BP climatic event. It synthesizes available cultural, demographic and palaeoenvironmental evidence by region between 3300 and 1500 BC. Important variation can be discerned through this comparison. The demographic signatures of some regions, such as the Meseta and the southwest, diminished in the Early Bronze Age, while other regions, such as the southeast, display clear growth in human activities; the Atlantic areas in northern Iberia barely experienced any changes. This paper opens the door to climatic fluctuations and inter-regional demic movements within the Peninsula as plausible contributing drivers of particular historical dynamics.     

Investigation of palaeodiet in the North Caucasus (South Russia) Bronze Age using stable isotope analysis and AMS dating of human and animal bones

This paper addresses the question of human palaeodietary adaptation in the Eneolithic and Early Bronze Age periods of the North Caucasus (South Russia) using stable isotope analysis. One of the key questions is the presence of fish in the diet. AMS radiocarbon dating of archaeological bone collagen has also been carried out to investigate potential radiocarbon reservoir effects in human skeletal material as a result of an aquatic diet. A fish component has previously been suggested in the diet of Iron Age and Bronze Age humans across Eurasia by isotopic research and radiocarbon dating of contemporaneous human and animal bones. In the North Caucasus however, isotopic data is scant. This study presents a new set of stable isotopic data from several Early Bronze Age sites, mainly belonging to the Maikop culture of the North Caucasus. The results show that the diversity in climate and environment across the northern Caucasus may be a causal factor for the patterns observed in the stable isotope values of terrestrial herbivores. This affects the isotopic values of the humans consuming them. The differences in δ¹⁵N and δ¹³C ranges of both humans and fauna were found to correlate strongly with geography and climate; the most enriched isotopic values are found in the dry steppe areas to the north. Overall, a relatively high enrichment in δ¹⁵N values of humans compared to local terrestrial herbivores and carnivores was observed. This indicates that aquatic resources were probably part of the Bronze Age diet in the region although the extent of this needs further investigation. The dramatic effect of environmental factors on isotopic values in the Early Bronze Age of the North Caucasus illustrates how confident conclusions cannot be drawn on the basis of a small number of samples from widely differing regions and time periods. Radiocarbon dating can provide a useful tool for identifying dietary derived reservoir ages in humans, potentially caused by a fish diet. With two possible exceptions, the nine human–animal bone pair dated as part of this study showed no consistent indication for a consistent reservoir effect.     

When the Giant Falls: Endurance and Adaptation at Çadır Höyük in the Context of the Hittite Empire and Its Collapse

At the end of the Late Bronze Age, around 1200 b.c., the Hittite Empire of Anatolia collapsed. While that collapse has been well studied, the effects on Hittite-held lands are less so, with many archaeologists positing an abandonment in Hittite territories for a period of time early in the Iron Age. Recent excavations at Çad?r Höyük, 70 kilometers from the Hittite capital, have revealed both typical Hittite material culture belonging to the Late Bronze Age, including mass-produced ceramics and massive fortifications, as well as evidence suggesting that the site’s residents faced challenges, and adapted accordingly, in the wake of Hittite withdrawal and collapse, during the Early Iron Age. The architecture, ceramics, and zooarchaeological evidence from this rural settlement suggest ways in which residential continuity, cultural resilience, and technological and economic adjustments allowed inhabitants to survive and rebound in the face of political instability.     

Bronze Age Barrows: Factors Influencing Their Survival and Destruction

This paper analyses the influences on the survival of Bronze Age round barrows in two regions of southern Britain, the Upper Thames Valley and the Stonehenge Environs. It is clear that persistent arable farming in the medieval period had a highly destructive effect on these burial mounds. This can be seen despite later agricultural activity. Other factors such as the type of barrows can also be important factors in the survival and destruction of these burial mounds. Nevertheless, when analysing the distribution of these Bronze Age monuments, later historic land use must be considered as well as the contemporary prehistoric landscape.     

Millet cultivation history in the French Alps as evidenced by a sedimentary molecule

We report on the detection, in a sediment core drilled in Lake Le Bourget (French Alps), of a fossil molecule (miliacin) that was synthesized by broomcorn millet cultivated in the watershed, and then exported to the sediment. The variation in abundance of this molecule allows us reconstructing the history of millet cultivation around Lake Le Bourget. Our results support the introduction of millet around −1700 BC in the region. After an intensive cultivation during the Late Bronze Age, the failure of millet cropping during the Hallstatt period coincides with a phase of climatic deterioration. Millet cultivation recovers during the Roman and Mediaeval periods before falling most probably due to the introduction of more productive cereals. These pioneering results constitute the first continuous record of an agrarian activity covering the last 6000 years and emphasize the close relationships between local hydrology, land use and agro-pastoral activities around Lake Le Bourget.     

A spatial approach to upland vegetation change and human impact: the Aber Valley,Snowdonia

Abstract

Uplands have long been considered important ‘barometers’ for human-environment relationships. Five pollen sequences from the upper Aber Valley (Snowdonia), across an altitudinal gradient, reveal that human impacts have varied temporally on small spatial scales in the region. Woodland taxa persisted into the later Holocene at lower altitudes and sites located at higher altitude reveal a more open landscape history, possibly as a result of increased exposure limiting tree growth at high elevation. Continuous pastoral human land use is evident in the high upland (400 to >600 m AOD) landscape with evidence of clearing, burning and grazing indicators throughout the records covering the last ～6000 years, with increased activity apparent during the last 2000 years. There is no clear evidence to suggest that climate change (e.g. deteriorating climatic conditions from ～850 BC) resulted in land abandonment and it appears more likely that climatic shifts could have led to changes in human land management. The results demonstrate that pastoral land use varied at different altitudes across the Aber Valley upland, and have highlighted the value and potential of high/fine spatial sampling in providing insights into land use history and the mosaic of habitats that result.     

SHIFTING SETTLEMENT PATTERNS IN THE SOUTHERN JORDAN VALLEY AND DESERT FRINGES OF SAMARIA DURING THE EARLY BRONZE AGE I PERIOD

Abstract

This study deals with the unprecedented settlement activity during the Early Bronze Age I that has been recently recorded in the Jordan Valley and the desert fringes of Samaria. The increase in the number of sites primarily characterises the latter part of the period (Early Bronze Age IB), and is accompanied by two other important phenomena: population inroads into new regions, and the first appearance of fortified sites. A profound crisis at the end of the period resulted in the almost complete abandonment of the valley sites and the concentration of settlement along the eastern foothills of Samaria.