Holocene climate change in Glen Affric, Northern Scotland : a multi-proxy approach

A multi-proxy approach was used to generate a continuous, sensitive Holocene palaeoclimatic record for Glen Affric, north west Scotland. Fluctuations in lake-level were used as a proxy for shifts in precipitation. Rigorous site selection criteria and a new methodology were developed to interpret the lacustrine sediment record in terms of climatically driven changes in water depth by separating (a) allogenic from autogenic sediment inputs and (b) explicitly linking the marginal fen peat system responded to changes in lake-level. The sedimentary record from the lake site, Loch Coulavie, suggests that lake-level has fluctuated repeatedly throughout the Holocene. The comparative magnitude of changes in lake-level defined the relative intensity of shifts in precipitation. Variations in mire surface wetness, as determined through humification analysis, from a series of four hydrologically isolated ombrotrophic blanket mire sites through the east-west trending glen, were used to generate a record of changes in effective precipitation. A reliable radiocarbon chronology obtained from both proxy records allowed the synthesis of these data sets and the definition of Holocene climate change in terms of relative shifts in temperature and precipitation. The data suggests that the early Holocene was more stable in terms of both temperature and precipitation, but that after c. 6200 BP (7200 cal. BP) both temperature and precipitation became highly variable. Several short-lived, abrupt high intensity shifts to increased precipitation occur at c. 6200 BP (7200 cal. BP), c. 5000 BP (5700 cal. BP), c. 3000 BP (3200 cal. BP) and c. 2400 BP (2350 cal. BP). Holocene climatic variability within Glen Affric corresponds to records of changes in North Atlantic oceanic circulation patterns. The predominance of atmospheric systems, such as Atlantic westerlies, may also have controlled spatial climatic variability within the glen, with the periodic establishment of very steep west-east climatic gradients, steeper than at the present day

Palaeoenvironmental evidence for woodland conservation in Northern Iceland from settlement to the twentieth century

Narratives of Norse arrival in Iceland highlight the onset of land degradation and loss of woodland cover as major and long-term environmental consequences of settlement. However, deliberate and sustained land resource management in Iceland is increasingly being recognised, and in this paper we assess whether woodland areas were deliberately managed as fuel resources. Our study location is the high status farm site at Hofstaðir in northern Iceland. A palynological record was obtained from a small basin located just inside the farm boundary wall and the geoarchaeological record of fuel use obtained from waste midden deposits associated with the farm. Both environmental records are temporally constrained by tephrochronology and archaeological records. When viewed within the broader landscape setting, our findings suggest that there was near continuous use of birch wood from early settlement to the present day, that it was actively conserved throughout the occupation of the site and that there were clear distinctions in fuel resource utilisation for domestic and more industrial purposes. Our analyses open discussion on the role of local woodlands and their management in the Norse farm economy

Possible climatically driven, later prehistoric woodland decline on Ben Lomond, central Scotland

Later prehistoric woodland decline over most parts of Scotland is widely regarded as having been anthropogenic, via a range of mechanisms, to create farmland. Climatic causes are seen only to have driven the rapid expansion and then terminal decline of Pinus sylvestris around 2000 cal BC. Here we report radiocarbon dated analyses of pollen, microscopic charcoal, coprophilous fungal spores and peat humification from a small, water-shedding interfluve peat bog at 230 m elevation on the west-facing slope of the mountain Ben Lomond in west-central Scotland. The record spans the interval ca. 3450 − 200 cal BC. It shows marked and rapid changes in woodland composition before ca. 2600 cal BC, and from then to ca. 1940 cal BC a gradual decline of Betula woodland. This happened with no palaeoecological or archaeological evidence for anthropogenic activity. Woodland decline is interpreted at this site as climatically driven, perhaps through paludification or, more likely, exposure to wind, within a period of pronounced climatic deterioration. Anthropogenic activities are hinted at only after ca. 850 cal BC.Output Status: Forthcoming/Available Onlin

Late glacial and Holocene climate variability, southernmost Patagonia

A Late glacial – Holocene palaeoecological record, constrained by a robust chronology, from a peat bog near Punta Burslem (54°54′S, 67°57′W) on Isla Navarino, southernmost Patagonia documents the shifts in intensity and focus of the Southern Westerly Winds (SWWs) at these high latitudes. Such long-term records are required to reconstruct and better understand the likely regional impacts of a poleward shift and intensification of the SWWs predicted under global warming scenarios. Deglaciation at Punta Burslem occurs sometime before c. 17,000 cal a BP, and the post glacial landscape is dominated by cold tolerant pioneer species. Nothofagus woodland is established by c. 12,250 cal a BP, this moisture sensitive vegetation type retreats in the early to mid-Holocene from c. 9700 to 7050 cal a BP reflecting an intense and sustained drier phase associated with a prolonged poleward contraction of the SWWs. After c. 6000 cal a BP there is a regional trend to cooler and wetter climate. However, we identify at least five periods of rapid climate change (RCC) leading to drier conditions at this southern extreme of Patagonia: c. 5350-4750 cal a BP, c.4300-3300 cal a BP, c. 2600-1850 cal a BP, c. 1350-1100 cal a BP and c. 550-350 cal a BP. From a synthesis of our Isla Navarino records and a latitudinal spread (34°-64°S) of multiproxy records it is proposed that these periods of RCC and relatively drier conditions indicate latitudinal shifts in the location and intensity of the SWWs in response to climatic warming leading to reduced precipitation at the southern margins of Patagonia

The landscape context of the Antonine Wall: a review of the literature

The landscape, environmental and land use changes before, during and after Antonine occupation are examined for the region of central Scotland between the Southern Uplands and the Grampian Highlands, principally from the published literature. The purpose is to synthesize and make available a range of new palaeoenvironmental data, to evaluate critically these new data-sets, to search for significant shifts in landscape or land use and to characterize their timings and effects, thus placing the Antonine occupation in a coherent landscape context. It is established that economic expansion in the region occurred in the later Iron Age, demonstrably before Roman military occupation. This expansion developed from Bronze Age and earlier Iron Age small-scale farms and gathered pace in the last cal 200–300 years BC, for crop growing as well as pasture, and was continued rather than intensified in the first two centuries cal AD. It is difficult to see differences in this economic expansion north and south of the Antonine Wall itself, or east and west of the Forth–Clyde isthmus, but it is tentatively suggested that in the foothills of the Southern Uplands the Romans entered a landscape already decaying. Roman influence is perhaps recognizable at some localities in a reduction of cereal production and the expansion of grazed pasture, assumed to represent a restructuring of the native economy to support a new market. It is presumed that imports of foodstuffs continued to be important to Roman forces during Antonine occupation, although possible reconstructions of the sediments in the Forth and Clyde estuaries suggest these may not have provided ideal harbours. There is little evidence that this increased pastoral economy imposed stresses on soils or plant communities, and the market seems to have been readily supplied within the agricultural capacity of the landscape. Nevertheless, the native economy was probably artificially buoyed by the Roman presence, and withdrawal eventually led to what is best described as an agricutural recession, not population collapse

Recognising geodiversity and encouraging geoconservation—Some lessons from Callander, Loch Lomond and The Trossachs National Park, Scotland

In the past decade progress has been made recognising the contribution that geodiversity makes to biodiversity and society. Scotland's Geodiversity Charter, launched in 2012 and revised in 2017, has attracted the support of almost 100 organisations and encourages signatories to work together to recognise the value of geodiversity and ensure it is managed appropriately and safeguarded. The case study presented here highlights that while there is a real desire to protect sites that are scientifically valuable, significant challenges exist to balance this with societal demand for resources and development. There are also challenges for geoscientists and geoconservation groups to communicate effectively with planning authorities and local communities. The case study also sheds light on the problems associated with the systems of designating geosites of national and regional importance, the maintenance of these systems, and how the value of these sites is conveyed beyond the scientific community. Scotland's Geodiversity Charter offers a framework that stakeholders can use to work in partnership to increase awareness of the issues and help achieve the sustainable management of geosites. Case studies such as Callander provide lessons and solutions to over come the challenges that arise and highlight the need for the participation of both national and local stakeholders.Output Status: Forthcoming/Available Onlin

Long-term woodland dynamics in West Glen Affric, northern Scotland

The former woodlands west of Loch Affric are described from pollen analyses. Related records of climate change from the analysis of lake-level change and peat growth are also presented to explore the importance of climate in driving woodland change. The woodlands were more diverse than extant pinewoods to the east, with a very considerable deciduous component. They developed in the early Holocene period, and brief periods of range expansion and contraction are recorded within a pattern of overall woodland stability over thousands of years, despite the high frequency and intensity of climatic excursions, until a final collapse in all woodland communities occurred at around 4000 calibrated years ago (BP). This collapse had a climatic origin, but the precise character of the climate change is ill-defined

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