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This special volume considers major recent changes in southern South American animal communities. Eleven papers consider megafauna, pinnipeds, marine mammals, small terrestrial mammals and birds and are grouped under four sub-headings: (1) Isotopic insights into guanaco populations; (2) Historical sources and marine ecosystem change; (3) Changes in small mammal communities and human impacts; and (4) megafaunal extinction, domestication, avifauna and recent interactions with humans. Although some of these contributions include changes that occurred earlier in the Holocene, many highlight a current decrease in the taxonomic diversity of communities and ecosystems in different environments, which are likely to have been caused by modern human activities. The Anthropocene concept is seen as providing a useful framework for understanding and mitigation of such adverse human impacts. [ABSTRACT FROM AUTHOR]

Peatlands store massive amounts of organic carbon, but the fate of this carbon remains unclear as global climate continues to warm. The age of peatland inception and the main drivers of peat initiation are one of the most important issues in Holocene paleoecology, especially for the numerous but under investigated peatlands in European Russia. This paper introduces new peatland initiation ages for 44 mires in three areas located in the central part of European Russia within the Polesie landscape belt. This region is characterised by waterlogged sandy plains and flat surface topography. Phases of peatland initiation were compared with Holocene fire regime derived from macro-charcoal data as well as with regional climatic reconstructions. We found that peat inception in the region started around 12,000 cal yr BP, but the most active phases of peatland initiation took place during the periods 8500–7500, 7000–6000, 5300–5800, 4000–3500 and 1700–1200 cal yr BP. Expect for rapid peat growth during the early Holocene, peatland initiation mostly coincided with warm climatic periods and increased fire frequency. Forest soil paludification in poorly drained Polesie landscapes was presumably enhanced by reduced evapotranspiration and changes in water balance due to disturbance of forest cover after wildfires. We expect that rising air temperature in the current century will cause higher fire frequencies and may encourage waterlogging of forests and ecosystem transformation. [ABSTRACT FROM AUTHOR]

We describe the career of John Birks as a pioneering scientist who has, over a career spanning five decades, transformed palaeoecology from a largely descriptive to a rigorous quantitative science relevant to contemporary questions in ecology and environmental change. We review his influence on students and colleagues not only at Cambridge and Bergen Universities, his places of primary employment, but also on individuals and research groups in Europe and North America. We also introduce the collection of papers that we have assembled in his honour. The papers are written by his former students and close colleagues and span many of the areas of palaeoecology to which John himself has made major contributions. These include the relationship between ecology and palaeoecology, late-glacial and Holocene palaeoecology, ecological succession, climate change and vegetation history, the role of palaeoecological techniques in reconstructing and understanding the impact of human activity on terrestrial and freshwater ecosystems and numerical analysis of multivariate palaeoecological data. [ABSTRACT FROM AUTHOR]

Within the framework of a regional research project on wetlands as cultural heritage sites, an attempt was made to examine the natural and anthropogenic causes driving the vegetation dynamics and exploitation of a small mountain wetland. To assess its potential use as an archive of the landscape history, an environmental archaeology approach was used: palaeoenvironmental data from traditional pollen sampling by coring were matched with stratigraphic information from an excavation area of several square metres, and plant micro- and macroremain analyses (e.g. pollen assemblages, micro- and macrocharcoal, morphological and dendrochronological features of waterlogged tree trunks) were compared in order to evaluate them as effects of different environmental factors and to pinpoint these factors. In this paper, the focus is set mainly on the results originating from pollen analyses of a core drilled in the peat-bog, a few metres from the stratigraphic excavation. The start of peat deposition, sometimes coinciding with human activity, was dated around 10,000 cal. BP. The impact on the vegetation surrounding the site is clearly recorded in the pollen assemblages only from the Roman period (2010–1820 cal. BP) even though a long history of human presence is archaeologically documented in the area since the Palaeolithic. Since that time, the abrupt decline of fir favoured the final spread of beech which, in turn, in the Middle Ages (1180–790 cal. BP) leaves space to grassland exploitable for pasture and for agro-silvi-pastoral activities. This site has proven to be of great importance for the Holocene history of the silver fir. [ABSTRACT FROM PUBLISHER]

The vast diversity of present vegetation and environments that occur throughout South America (12°N to 56°S) is the result of diverse processes that have been operating and interacting at different spatial and temporal scales. Global factors, such as the concentration of CO2 in the atmosphere, may have been significant for high altitude vegetation during times of lower abundance, while lower sea levels of glacial stages potentially opened areas of continental shelf for colonisation during a substantial portion of the Quaternary. Latitudinal variation in orbital forcing has operated on a regional scale. The pace of climate change in the tropics is dominated by precessional oscillations of c. 20 kyr, while the high latitudes of the south are dominated by obliquity oscillations of c. 40 kyr. In particular, seasonal insolation changes forced by precessional oscillations must have had important consequences for the distribution limits of species, with potentially different effects depending on the latitude. The availability of taxa, altitude and human impact, among other events, have locally influenced the environments. Disentangling the different forcing factors of environmental change that operate on different timescales, and understanding the underlying mechanisms leads to considerable challenges for palaeoecologists. The papers in this Special Issue present a selection of palaeoecological studies throughout South America on vegetation changes and other aspects of the environment, providing a window on the possible complexity of the nature of transitions and timings that are potentially available. [ABSTRACT FROM AUTHOR]

This paper describes our recent attempt to isolate and analyse DNA from old plant remains of the common peatmoss Sphagnum fuscum retrieved from a peat core collected in the mire Fuglmyra, in central Norway. DNA was recoverable and usable from subfossilized (10-450 years old) plant remains of the peatmoss. A chloroplast (trnL) and two nuclear (ITS2 and RAPDf) regions were co-amplified from 80 samples of different ages. The RAPDf region was the only variable one with three different haplotypes found among five samples. Comparison of the ancient sequences with modern sequences found in the extant population occurring at the same site ascertained a genetic link between modern and fossil samples of this species. This retrieval of ancient DNA from subfossilized moss remains isolated from peat cores has important implications for the palaeoecology of peatmosses by allowing direct estimates of plant population dynamics in space and time. [ABSTRACT FROM AUTHOR]

Pollen analysis of a 48 m AMS radiocarbon-dated sediment sequence from the Guadiana estuary provides the first record of Lateglacial and Holocene vegetation history in the Algarve province of Portugal. This paper focuses on the record of terrestrial pollen taxa, which document a series of forest expansions and declines during the period 13 000 cal. BP to 1600 cal. BP and provide insights into climate evolution in southwestern Iberia. The main vegetation phases identified in the Guadiana valley are (1) Lateglacial interstadial (Allerød) forest with Quercus and Pinus under a temperate, moist, continental climate; (2) a Younger Dryas forest decline (Quercus) and expansion of pinewoods, xeric scrub and open ground habitats (with Juniperus, Artemisia, Ephedra distachya type, Centaurea scabiosa type) under arid and cold conditions; (3) an early Holocene forest/scrub/open-ground vegetation mosaic developing under a warm, dry and continental climate; (4) a maximum of Quercus forest and thermomediterranean evergreen taxa (Olea, Phillyrea, Pistacia) reflecting a warm, moist oceanic climate between c. 9000 cal. BP and c. 5000 cal. BP; and (5) the expansion of shrublands with Cistaceae and Ericaceae under a drier climatic regime and increasing anthropogenic activity since c. 5000 cal. BP. Holocene episodes of maximum climatic aridity are identified in the record of xerophytic taxa (Juniperus, Artemisia, Ephedra distachya type) centred around 10 200 cal. BP, 7800 cal. BP, 4800 cal. BP, 3100 cal. BP and 1700 cal. BP. Regional comparisons suggest a correlation of arid phases across southern Iberia and northwest Africa, which can be related to abrupt North Atlantic coolings (Bond events). [ABSTRACT FROM AUTHOR]

This paper describes our recent extraction of ancient DNA (aDNA) from Holocene pollen and discusses the potential of the technique for elucidating timescales of evolutionary change. We show that plastid DNA is recoverable and usable from pollen grains of Scots pine Pinus sylvestris from 10 ka and 100 years ago. Comparison of the ancient sequences with modern sequences, obtained from an extant population, establish a first genetic link between modern and fossil samples of Scots pine, providing a genetic continuity through time. One common haplotype is present in each of the three periods investigated, suggesting that it persisted near the lake throughout the postglacial. The retrieval of aDNA from pollen has major implications for palaeoecology by allowing (i) investigation of population-level dynamics in time and space, and (ii) tracing ancestry of populations and developing phylogenetic trees that include extinct as well as extant taxa. The method should work over the last glacial oscillation, thus giving access to ancestry of populations over a crucial period of time for the understanding of the relationship between speciation and climate change. [ABSTRACT FROM AUTHOR]

This paper examines the importance of palynological site selection criteria, specifically basin size, for the detection of vegetation mosaics and small- or local-scale human activity within a spatially diverse, mosaic landscape. Using a site selection strategy which recognizes landscape patchiness, pollen analyses from three small peat basins (10-56 m diameter) in an open, exposed upland valley (>250 m OD) provide records which are sensitive to local vegetation mosaics and small-scale, localized agriculture. The results indicate c. 4000 [sup 14]C years (4400 cal. years) of land use, with spatial and temporal variations in the valley. Contrasts between the sequences suggest that local pollen production remains an important component of the pollen rain deposited in small peat basins, even in open environments; this is especially true of palynological 'agricultural indicators'. By comparison, sites with regional pollen source areas underestimate the spatial diversity of the upland landscape, and are insensitive to small-scale human activity in an environment where the fragmentary distribution of soils suitable for agriculture favoured a small-scale, dispersed pattern of farming. It is therefore essential to match the spatial resolution of pollen records with the grain size or scale of variations in the environment under investigation in order to sense the scale of mosaics in vegetation and agriculture within patchy landscapes. [ABSTRACT FROM AUTHOR]