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Palaeoecological investigations, involving pollen analysis, dendrochronology, and radiocarbon dating of bog-pine, provide the basis for reconstruction of vegetation dynamics, landscape development, and human impact in two contrasting parts of lowland northern Connemara, western Ireland, namely Ballydoo and Derryeighter in the east, and Renvyle/Letterfrack/Cleggan at the Atlantic coast some 40 km to the west. The history of Scots pine (Pinus sylvestris) is traced in detail. Standout features include the dominant role the tree played from the early Holocene onwards and especially at Ballydoo, its ability to grow on peat surfaces (so-called pine flush) over the course of several millennia during the mid-Holocene (centred on c. 5 ka), and its demise in a three-step fashion to become regionally extinct at c. 2.3 ka. The factors influencing these developments, including climate change, are discussed. Another natural phenomenon, namely the spread of blanket bog, is shown to be an on-going process since the early mid-Holocene, with accelerated spread taking place during the Neolithic and Bronze Age. The course of human impact, as reflected in pollen records and in archaeological field monuments, including megaliths and prehistoric stone walls, is reconstructed in detail.

This study provides the first mid to late Holocene chironomid-inferred temperature (C-IT) model for northwest Ireland, creating a valuable climatic context for the development of Irish society during the Neolithic and Bronze Age. Using a lake sediment core from an isolated catchment, Lough Meenachrinna in northwest Ireland, a multi-proxy approach of chironomid (Diptera: Chironomidae) subfossils, sediment geochemistry (δ13C, δ15N, C:N) and pollen analysis was used to assess any potential limnological impact from prehistoric human activity in the region and provide a quantitative summer temperature estimate for the late Mesolithic to the Iron Age (7050–2050 cal yr BP). The pollen record provides a local signal of human activity, showing low levels of pastoral indicators in the early Neolithic, with increased evidence for pastoral and arable farming during the Bronze Age and in particular the Iron Age. Human activity does not appear to be a driving force in lake system change at Lough Meenachrinna, as peaks in farming indicators (e.g. pastoral pollen indicators and increased δ15N values) were not concurrent with major fluctuations in the chironomid assemblages. C-ITs provide evidence of multiple fluctuations in temperature during the mid to late Holocene with a cold phase during the late Mesolithic (6800–5890 cal yr BP), followed by a warming period during the early Neolithic (5890–5570 cal yr BP). C-ITs reflect a relatively warm climate during the middle Neolithic, with a substantial warming from the late Neolithic into the early Bronze Age (4630–3810 cal yr BP). C-ITs show a general cooling trend from the Bronze Age into the Iron Age, with a cold event occurring at 3340 cal yr BP during the middle Bronze Age and second cold event at 2430 cal yr BP during the Iron Age. The multi-proxy approach has proven an effective strategy for untangling human and climate influences on the chironomid record, and is recommended as a methodological approach in future Holocene climatic reconstructions where prehistoric human influence is a factor.

We conducted high-resolution palynological analysis on a sediment core obtained from Lough Muckno, County Monaghan, Ireland. The results presented represent the first paleoecological account of Mid-Late Holocene vegetational change and land-use dynamics in the study region. Human activity and agriculture is first recorded during the Early Neolithic (ca. 3870–3500 B.C.). After a period of undiscernible human activity of ∼900 years, farming resumes during the Early Bronze Age (ca. 2600 B.C.). Henceforth, human presence on the landscape is constant with fluctuating levels of intensity. During the Bronze Age, anthropogenic activity is most pronounced during ca. 2000–1750 B.C. and ca. 1500–1300 B.C. followed by a phase of reduced intensity in the Late Bronze Age (ca. 1000–650 B.C.). Farming activity increases during the Iron Age and is disrupted with the onset of a period of rapid woodland regeneration from ca. 200 B.C. to A.D. 200. During the prehistorical period agriculture has a strong focus on pas...

The results of radiocarbon dating and dendrochronological investigations of timbers (mainly pine and oak) preserved in coastal peats on the Atlantic coast of mid-western Ireland are reported. These are complemented by the results of pollen analytical investigations, including a detailed pollen profile from Lough Atalia, a brackish lake located within present-day Galway city and immediately to the east of the medieval town. The results from the fossil timber investigations show that pine stumps exposed on coastal intertidal peats in mid-western Ireland date mainly to ca. 3000 BC, that is, they are coeval with the so-called ‘pine flushes’ on blanket bog in western Ireland. Many of the oak timbers are considerably older while an oak on peat in Turlin Bay, near Silverstrand, persisted until ca. 2100 BC. This fossil timber record, taken in conjunction with the pollen records, suggests conditions very different to those pertaining at present, including absence of direct marine influence because of relative sea levels (RSLs) that were probably at least 2 m, and possibly up to 4 m, lower than at present. Mid-Holocene conditions were less stormy, and lower precipitation and/or higher evapotranspiration facilitated tree colonisation of peat surfaces. Intertidal peat layers at Salthill show that present-day RSL began to be approached at ca. AD 500. This agrees with the evidence from An Loch Mór, Inis Oírr, which indicates that salinity in this brackish lake began to increase noticeably at/immediately prior to ca. AD 1000. A notable feature of the pollen record from L. Atalia is a yew ( Taxus)-dominated woodland phase of ca. 600 years duration centred on 2550 BC. A major and widespread expansion of yew at about this time is a distinctive feature of mid-Holocene woodlands in western Ireland.

The Aran Islands are exceptional cultural landscapes at the Atlantic fringe of Europe. They are strongly influenced by human settlement and small-scale farming that is still pursued according to traditional practices. Reconstruction of changes in farming from the beginning of the early 20th century onwards, and demographic changes beginning in the early 19th century, are discussed in the light of official statistics. Field surveys, aimed mainly at documenting the extent of Secale cereale (rye) cultivation, provide more precise information on the extent of rye cultivation in recent decades and give fresh insights into present-day flora, vegetation, and plant biodiversity. Results from a previously published, lake sediment-based Holocene pollen profile from Inis Oírr are re-assessed in the light of modern-day pollen deposition studies that we carried out. We discuss the implications of long-distance pollen transport for the interpretation of Holocene pollen diagrams in relation to the history of trees, including Pinus sylvestris (Scots pine), in Ireland, and we emphasize the importance of supporting traditional farming practices, particularly as regards cereal growing, on the Aran Islands. peer-reviewed

Curves for Holocene lake levels and salinity changes are presented for An Loch Mor, a small oligohaline lake on the Aran Islands off the west coast of Ireland, based on palaeoecological investigations of a 12 m long, lake-sediment core. New insights are also provided into Holocene sea-level change in the Galway Bay region. Particular emphasis has been placed on the ostracod fauna, both past and present. Salinity and lake-level changes were reconstructed from the fossil ostracod assemblages, based on the known tolerances of individual species and on the assemblages as a whole. Additional evidence was provided by other proxies including strontium–isotope ratios derived from ostracod shells and other carbonates, plant macrofossil and pollen analyses, and sedimentological changes. The early Holocene (pre-Boreal, i.e. 11.5–10 ka) was characterised by low lake levels and slightly elevated salinity values, probably the result of high evapotranspiration and low precipitation rather than elevated sea levels. Early Holocene plant and animal migration to the island does not seem to have been impeded but relative sea levels were not necessarily so low (below −40 m a.s.l.) that landbridges were present to the mainland. Between ca 10 and 8.5 ka, relatively high lake levels prevailed. At 8.3 and 7.5 ka, minor fluctuations (lowering) of the lake level occurred that are assumed to relate to early Holocene abrupt events. Beginning at 7.05 ka, lake levels declined sharply. A general trend towards rising lake levels started at ca 6.4 ka and accelerated at ca 5.6 ka as runoff increased as a result of Neolithic clearances. At ca 4.8 ka, lake levels began to rise once again, probably in response to changes in rainfall and/or evapotranspiration and runoff. Lower lake levels during the first half of the 1st millennium AD were probably a response to decreased runoff as a result of a drier climate coupled with regeneration of woody vegetation. The sharpest rise in both lake levels and salinity began during the ninth century AD, which is attributed to a rapid rise in relative sea level.

The study of charcoal produced by five burning episodes that occurred in a rapid succession within a ritual pit dating to the late Iron Age at Raffin Fort, Co. Meath, Ireland, reveals considerable variation in the charcoal assemblages resulting from each burning episode. Wood selection processes are considered against the background of information on woodland composition and land-use history provided by a detailed pollen diagram from nearby Emlagh Bog, the chronology of which is based on both AMS 14C dates and tephra analysis. A human skull fragment lay on top of the charcoal layers but the radiocarbon evidence indicates that the skull predated the burnings by at least a century. This and other evidence indicate a ritual pit with the skull as a human relic. It is suggested that, in this instance, wood selection was neither random nor determined solely by availability or combustibility, but instead may have been informed by socio-religious belief systems pertaining to trees and wood. Early Irish documentary sources, which reveal a complex ethnography of wood and trees in later prehistoric and early historic Ireland, are reviewed. The results shed fresh light on aspects of late Iron Age archaeology in a part of Europe that was outside the direct influence of the Roman world. New information is provided on a distinctive feature in late Holocene Irish pollen records namely the Late Iron Age Lull (ca. a.d. 1–500). During this time, widespread regeneration of woody vegetation took place. In the subsequent early Medieval period renewed farming activity resulted in substantial decline in woodland, a pattern also seen at many other locations in Ireland.

Twelve definable cryptotephra layers younger than c. 8600cal. BP are reported from lacustrine core material taken from An Loch Mór, Inis Oírr, Aran Islands, western Ireland. The geochemistry of these shard layers, which represent more Holocene tephras than previously geochemically characterized from any European site outside the proximal volcanic influence of Italy or Iceland, is presented. Of these tephras, four may correlate with known Iceland-derived tephra horizons (Vo 1477, HI, Lairg A and H5); one appears to have two possible named correlatives (Hoy;‘Lairg B’ at Sluggan Bog, N Ireland); another has a plausible correlative (AD 860A); but two others represent Icelandic tephras apparently not previously reported on Iceland itself, including a tephra that has geochemistry very similar to Hl (AD 1104) but which dates to c. cal. AD 840. Four tephras that date from the period c. AD 40-1400 have a distinct geochemical signature that relates to Jan Mayen, 750km to the northeast of Iceland and some 1800km distant from An Loch Mór. The results contribute substantially to the chronology of the sediments from An Loch Mór and, at the international level, to the tephrostratigraphy of the northeast Atlantic region. The well-attested Icelandic H4 tephra (from a Hekla eruption of c. 4260cal. BP) was not recorded; it is suggested that An Loch Mór lies south of its recordable distribution in this part of the northeast Atlantic region. Taken together with work at other sites, the findings point to a wealth of potential tephra isochrons in Holocene deposits of the northeast Atlantic seaboard. It is clear also that calcareous lake sediments can be as fruitful a source of tephras as peats. Potential problems relating to dating and geochemical fingerprinting of tephra layers in individual sites are highlighted with reference to the Lairg tephras as recorded in Scotland and Northern Ireland, and to the Hoy tephra that has been described from Orkney.

A detailed Holocene pollen record, elaborated in the project TIMECHS, is presented from An Loch Mor, a deep lake at the north-eastern end of Inis Oirr, Aran Islands, western Ireland. Woodland development in the early Holocene is broadly comparable, as regards the general sequence of tree spread and overall woodland composition, to that known from mainland sites in the nearby Burren and Connemara. The main trees in the early Holocene woodlands were Quercus, Pinus and Ulmus. Corylus and a variety of tall shrubs including Betula, Juniperus, Rhamnus catharticus, Ilex, Viburnum opulus and Sorbus had an important role. Taxus expanded and attained dominance for a short period in the later Neolithic and then persisted in small numbers until at least the beginning of the early Medieval period (late 6th century AD). Other notable features included substantial opening-up of woodland cover prior to the Elm Decline, a well-defined Landnam in the early Neolithic (after the Elm Decline), considerable though varying human impact throughout the Bronze Age and continuing into the Iron Age, a distinct regeneration phase that involved regeneration of woody plants—mainly Juniperus, Corylus and Taxus—in the late Iron Age, i.e. the so-called Late Iron Age Lull, and renewed farming activity in the early Medieval period with Secale being introduced in the early 8th century AD. The final demise of woodlands took place between the 13th and the beginning of the 16th centuries though minor amounts of woody vegetation probably persisted on Inis Oirr until at least the late 18th century. The palynological record is discussed in the light of the available archaeological and historical information, and with particular reference to the recently completed archaeological excavations at Dun Aonghasa, the largest stone fort on the Aran Islands.

Results of palaeoecological investigations at Lough Sheeauns, a small lake in Connemara, western Ireland, are presented. The main pollen profile spans the period c. 9500 to 1500 B.P. and provides a detailed record of woodland and land-use history. The percentage, concentration and influx pollen diagrams are interpreted in the light of the results from a peat profile taken from near the lake margin and pollen analytical investigations of the recent lake sediment and of peat and peat-covered soils in the region. The rise of Pinus immediately prior to the expansion of Alnus (6700 B.P.) and its subsequent decline are interpreted in terms of low, followed by rising, lake levels. There is evidence for pre-Elm Decline Neolithic activity and, in the immediately post-Elm Decline, an intensive early Neolithic Landnam phase is recorded. It is argued that the Elm Decline is not ascribable to Neolithic activity; an explanation involving disease is favoured. On the basis of results of radiocarbon dating, the early Neolithic Landnam phase is estimated to have lasted 340 calendar years, with intensive pastoral-based farming lasting only c. 150 calendar years. For much of the mid and later Neolithic, palynological evidence for farming is lacking. In the late Neolithic/early Bronze Age (post 4100 B.P.) anthropogenic activity is again registered, at first weakly and then strongly towards the end of the Bronze Age (2900 B.P.). The characteristic lull in human activity known from elsewhere in Ireland is recorded in the late Iron Age (c. 2160 to 1810 B.P.). It is followed by an upsurge in anthropogenic indicators and a reversal in a 14 C date. These changes reflect widespread woodland clearance and intensive farming activity in the catchment which are probably linked with early Christian settlement.

Palaeohydrology of the brackish karst lake An Loch Mor (Inis Oirr) was reconstructed based on its 11 600 year sedimentation record. Low calcareous early Holocene sediments, characterized by high TOC contents and deposited at generally low accumulation rates, show a gradual decrease upwards in the concentration of the siliciclastic sediment until c. 7000 cal. yr BP. From c. 9000 cal. yr BP, sediment accumulation became increasingly dominated by the deposition of autochthonous calcite and organic matter. The deposition of autochthonous calcite and its chemical composition (Ca/Sr, Ca/Mg) are determined by the subsurface inflow of freshwater from the catchment of the lake and by the balance between freshwater and seawater influx. During the early Holocene, the lake mainly received input of sea salt by sea-spray. The sediments document the further development from seasonal towards the onset of diurnal infiltration of seawater at c. 5100 cal. yr BP. At that time, the relative sea level must have risen nearly to its present level in Galway Bay. Diurnal seawater infiltration during high tides was controlled by freshwater input. Freshwater inflow from the catchment gradually increased with human impact on local vegetation (EVPT decrease). Permanent diurnal seawater infiltration in concert with this general freshwater increase made the geochemical sedimentation record highly sensitive to changes in annual precipitation. We use information from the palynological record to interpret geochemically inferred freshwater inflow variations in terms of dry and wet climatic periods and document distinct century-scale successions between wet and dry climatic episodes for western Ireland.

There are few historical analyses quantifying impacts of human activity in Australia. This paper compares vegetation change, fire regime, erosion and eutrophication rates between the European period and the recent prehistoric past in two lake systems on the south coast of New South Wales. The variance in pollen abundance and hence species population changes increased markedly in the historical period, especially amongst understorey taxa, and this could be related to changes in the local fire regimes and to the effects of grazing. Local fire activity decreased from the prehistorical period at both sites. Erosion rates increased in the historical period and both organic and inorganic components were deposited in the lakes. Erosion episodes could be related to fire during some periods but are clearly controlled by forest disturbance and land-use at other periods. The trophic status of the lakes was increasing from before European settlement but accelerated in the recent past. This was in part due to the increased erosion rates and in part due to fertiliser application. The results suggest that lower rates of erosional and eutrophic change occur in catchments with basaltic than with Holocene sand substrata.

Summary Results of palaeoecological investigations on a core from Lough Sheeauns, N.W. Connemara, a small lake sited in an area with a dense concentration of megaliths datable to the Neolithic, are reported. Pollen analysis, involving continuous sampling over a 41 cm interval spanning the elm decline (c. 5000 B.P.), permitted a detailed reconstruction of the vegetational changes and the nature of human impact. The pollen data are supplemented by chemical analysis and a chronology is provided by radiocarbon dating. Farming, including cereal cultivation, in the century prior to the elm decline is demonstrated. The elm decline emerges as a distinct feature in both percentage and concentration pollen diagrams. It is argued that neither an anthropogenic nor a climatic explanation for that event is sustainable in the light of the available evidence; a disease hypothesis is favoured. In the immediate post-elm decline period, Landnam, involving major woodland clearance in the context of a pastoral-based Neolithic economy, is recorded as a distinctive feature in the pollen record.