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This study provides a new record of nitrogen (N) deposition and ecological response at a remote, high-elevation lake within the ecologically fragile Three River Headwaters Region, northwest China, from the early 20thCentury to the past decade. A multi-proxy investigation of a lake sediment core including analyses of chironomids (non-biting midge), lake sediment geochemistry (δ15N, δ13C, TN, TOC, OC:TN), pollen, non-pollen palynomorphs and 210Pb-dating. Results were compared with regional pollution forcings, including fertiliser application, atmospheric nitrate and dust deposition, and a localised multiscale air quality modelling system for N-deposition. Our data reflect a mesotrophic lake for the majority of the 20th Century with minimal anthropogenic impact. A shift in the lake conditions is evident after 1985 with increased nutrient enrichment. Low δ15N, OC:TN and increasing TN values, together with an increase in chironomid taxa associated with eutrophic conditions and macrophytes are exhibited in the record, particularly since 2002. These changes are consistent with nutrient loading causing a change in trophic status. Redundancy analysis (RDA) and partial RDAs verified TN as an important driver behind the shift in chironomid community composition in recent decades, explaining 22.2% of the variance on its own and 16.9% with other environmental variables partialled out. While temperature change since 1960 was not a primary control on the chironomid community of Lake Bander, a step-change increase in summer temperatures since the 1990s coincided with the disappearance of cold stenotherms from the record and seems to have exacerbated the shift to more productive conditions. This study highlights the reach of airborne N from modern agricultural and industrial activity to remote locations, and demonstrates the utility of palaeolimnological techniques as part of modern ecosystem assessment for conservation.

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 paper presents the results of a multi-proxy, palaeolimnological investigation of Lough Inchiquin, a large lake located immediately south of the Burren, a distinctive karst landscape in Co Clar...

This paper presents new palaeoecological data from north Co. Mayo, western Ireland, and reviews published data with a view to achieving a better understanding of the timing and nature of early farming in the region, its impact on the natural environment, and the factors, including climate change, that influenced mid- and late-Holocene vegetation dynamics and farming in the region. A long pollen profile from Glenulra, a deep basin situated within Céide Fields, and short profiles from blanket peat that overlies the prehistoric stone-wall field system, provide unambiguous evidence for substantial farming, including widespread woodland clearance, in the early British/Irish Neolithic (beginning ca. 3800 BC). This was followed by a distinct lull that lasted several centuries with farming activity resuming again, at first modestly (at ca. 2700 BC), and more markedly at 2350 BC, i.e. at the Neolithic/Chalcolithic transition. It is argued, on the basis of this and other palaeoecological evidence, including pollen analytical investigations at nearby Garrynagran, that, contrary to recent suggestions, there is no reason to doubt the widely held view that the stone-wall field system unique in a western European Neolithic context is correctly ascribable to the earlier part of the British/Irish Neolithic. The history of pine growing in bog contexts (mainly blanket bog) in the region is considered in the light of 14C dates derived from pine timbers, and the results of dendrochronological investigations at Garrynagran, that have enabled two floating pine chronologies to be constructed, are presented. The climatic implications of these data are discussed within local and wider regional contexts. This research has been supported by the Heritage Council of Ireland (grant no. 1993), Forbairt/Eolas (Ireland; grant no. 1995) and an NUIG Postgraduate Fellowship (1992–1995). The article processing charge was funded by the Quaternary scientific community, as represented by the host institution of EGQSJ, the German Quaternary Association (DEUQUA). peer-reviewed

Recent studies have shown that video games alter cognition in teenagers, but it is unknown how teen cognition changes in the short-term directly after playing video games. This study measured the differences in selective attention, processing speed, sustained attention, and cognitive flexibility of video-game playing (VGP) adolescents at different time intervals after playing video games. Three different reasoning tests were used: the Paced Auditory Serial Addition Test (PASAT), the Sustained Attention to Response Task (SART), and the Stroop Task. A custom 250 question arithmetic test was also used, but was unable to uncover processing speed differences between VGPs after playing video games. All VGP participants in the study underwent reasoning tests before playing video games, played League of Legends (LoL)—known for its intensive use of spatial awareness, cognitive decision making, and working memory—for an hour, and then took reasoning tests once again at different times after having played LoL. This experiment affirms that video games create cognitive enhancement, though the experiment uncovered that VGP teens have worsened selective and sustained attention as time elapses after playing video games. Future research may want to extend the variable of time to test how video games affect attention or cognition by time in a longer term with a larger sample size.

This paper is a palaeoenvironmental investigation into prehistoric farming activity in the southern Burren, a distinctive karst landscape in western Ireland, from the Mesolithic to the Early Iron Age (ca 4600–10 bc). This archaeologically rich landscape has been exploited by humans since the Neolithic and both the archaeological record and published pollen records from the area attest to its importance in early prehistory, specifically from the Early Neolithic–Early Bronze Age. Pollen, macrofossil and loss-on-ignition analyses were undertaken on a sediment core extracted from Lough Inchiquin, a large lake immediately south of the Burren. Previous investigations in this region all focused on small lake basins which provided only local signals of land-use offering conflicting insights into the land-use dynamics of later prehistory. With a scarcity of known archaeological evidence for Late Bronze Age activity in this region, the current narrative has been one of decreasing importance at this time. Through the establishment of a robust chronology, this paper presents the palaeoenvironmental evidence for human activity, focused on anthropogenic indicators, in conjunction with the archaeological data, from the Mesolithic to the Early Iron Age, to provide a detailed account of landscape change. The new data provide a more regional signal of land-use across the wider Burren landscape than previous studies and highlight an intense period of exploitation from ca 1210–560 bc that resulted in a Late Bronze Age Landnam.

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.

High-resolution palaeolimnological analysis was implemented on a sediment core from Lough Muckno, a historically polluted inter-drumlin lake located in northeast Ireland. Focusing on chironomid and fossil pollen analyses, catchment conditions and human impacts on the lake environment during the last c. 200 years are identified and characterized. Chironomid community response to historical land-use change, reconstructed through a combination of pollen analysis and documentary evidence is evaluated in detail. The results provide insights into lake ecological conditions from a meso-eutrophic state in a nineteenth century agricultural setting to a highly eutrophic system in a landscape under modern pastoral management. Increasing livestock numbers and concomitant land fertilization are considered to be the main drivers affecting chironomid assemblages. Redundancy analysis indicates that grassland-based agriculture, inferred from Poaceae (grasses), the dominant component of palynological pastoral indicators, was the main variable controlling chironomid community composition. Lake resilience to nutrient abatement is reflected in a limited chironomid response to declining agricultural activity during the Great Irish Famine (c. 1846) and attempts at point and non-point pollution controls. Integrated interpretation of chironomid, pollen and non-pollen palynomorphs is shown to be a powerful tool for assessing the impacts of modern land-use change on lake ecology through time.

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.

Analysis of short tandem repeats (STR) is the predominant method for post-transplant monitoring of donor engraftment. It can enable early detection of disease relapse, level of engraftment and provide useful information on the graft-versus-host disease (GVHD)/graft-versus-tumour (GVT) effect, facilitating therapeutic intervention. Harmonization and standardization of techniques and result interpretation is essential to reduce the impact of laboratory variability on both clinical management and the results of multi-centre clinical trials. However, the United Kingdom National External Quality Assessment Service for Leucocyte Immunophenotyping (UK NEQAS LI) has highlighted significant issues inherent in STR testing that impact upon inter- and intra- laboratory variation. We present here consensus best practice guidelines and recommendations for STR chimerism testing, data interpretation and reporting that have been drawn up and agreed by a consortium of 11 UK and Eire clinical laboratories. This document uses data obtained from the UK NEQAS LI Post-Stem Cell Transplant (SCT) Chimerism Monitoring Programme.

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.

We describe an unexpected finding of diffuse large B-cell lymphoma associated with mature cystic teratoma of the ovary. A 68-yr-old woman with a complex left ovarian cystic mass on imaging underwent bilateral salpingo-oophorectomy, lymphadenectomy, appendicectomy, and omentectomy. Histopathologic examination revealed nodules of malignant non-Hodgkin lymphoma within the teratoma. A diagnosis of diffuse large B-cell lymphoma, germinal center cell subtype by Hans criteria was made after immunostaining and molecular studies. The patient was treated with R-CHOP chemotherapy and remains disease-free at 14-mo follow-up.

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.

Hematopoietic chimerism is a measure of the number of donor and recipient cells in the host following stem cell transplantation (SCT). The type of conditioning therapy prior to SCT has a major impact on the chimeric status in the recipient. Different techniques of measurement have varying sensitivities. The use of polymerase chain reaction (PCR) of short tandem repeats (STR) using fluorescent amplification permits quantification using Genescan analysis. When SCT is used for malignant haematological disorders, measurement of chimeric status may indicate early relapse and in aplastic anemia graft rejection. Reduced intensity or T-cell depletion is associated with mixed haemopoietic chimerism. SCT for benign haematological disorders does not require complete donor chimerism for a successful outcome.

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.

1. Results are presented of palaeoecological investigations at Derryinver Hill, an important archaeological site in the Renvyle Peninsula, Connemara, western Ireland. 2. Four short radiocarbon-dated pollen diagrams have enabled land-use history on the Hill during late prehistory and the early historical period to be reconstructed in considerable detail. 3. It is shown that pre-bog walls on the Hill — the first to be dated in Connemara — were laid out at 2400 BP, but it was not until 1700 BP that peat accumulation began locally. 4. The evidence indicates that, though grassy heath conditions existed prior to the stone wall construction, peat initiation was retarded through land-use management. When management ceased, the grassy heathland gave way to blanket bog. 5. These findings are discussed in the light of results from a long radiocarbon-dated peat pollen profile from the base of Derryinver Hill and of other palaeoecological investigations in north-western Connemara.

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.