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Aim To investigate the human impact on eastern Mediterranean ecosystems in a subhumid to semi-arid region of the Near East. Location This paper considers data from Bereket (1410–1440 m a.s.l.), an intramontane basin surrounded by the Kokayanık Tepe (1830 m a.s.l.) and the Beşparmak Dağları (2280 m a.s.l.), in the western Taurus Mountains of south-west Turkey. Methods Late Holocene samples were collected along an 800-cm-deep sediment profile cored in the secondary valley of the Bereket basin. Descriptive vegetation data and modern pollen samples (moss polsters) were collected at elevational intervals of c. 15 m along an altitudinal transect from the Bereket basin (over Tepe Düzen, 1600 m a.s.l.) to Ağlasun Dağı (1700 m a.s.l.). Information about the spatial distribution of the present land cover was obtained from ASTER satellite imagery. Digital elevation-derived data and geological information were used to examine the relationship between actual land cover and other environmental variables. Results The well dated Bereket sequence provides a unique record of biennial-to-decadal landscape changes driven primarily by intensive human impact from 360 cal. yrbc to 650 cal. yrad. Since 360 cal. yrbc, over-exploitation of the land has led to altitudinal variation of tree lines, a destruction of the natural forest ecosystems ( Pinus– Quercus cerris mixed forest), and an extensive spread of forest-steppe in the highlands. The present-day distribution of vegetation in the basin area shows that human activities remain the major factor influencing the character of modern ecosystems. Main conclusions This research demonstrates the long-term local destructive effects of human impacts on the mountainous ecosystems in a small Anatolian intramontane basin since 360 cal. yrbc, and the capacity of these ecosystems to recover during periods of reduced human impact. The late Holocene history and modern vegetation characteristics show that the past and present-day distribution and composition of vegetation are influenced primarily by human activity, and that substrate, elevation, slope and orientation are of secondary significance. [ABSTRACT FROM AUTHOR]

This paper presents a new palynological record from a 146 cm long finely laminated sediment core obtained in 2009 from the deep-water meromictic Lake Shira (54°30′38″N, 90°12″09′E; ca. 353 m a.s.l.) situated in the Khakassian steppe region of southern Siberia between the rivers Ob' and Yenisei. The area is rich in lakes and represents an exceptionally well preserved sequence of Bronze and Iron Age archeological cultures. Little is known about the changes in vegetation and climate of the region during the Holocene. The palynological analysis of the core allows us to partly fill up this gap in current knowledge. The record of pollen and non-pollen palynomorphs presented here covers the past 2450 year interval with an average resolution of 22 years. The results obtained support the interpretation that the late Holocene vegetation changes around Lake Shira are mainly associated with large-scale atmospheric circulation processes controlling the regional water balance rather than with human activities. An attempt to trace human impact in the pollen assemblages provides no clear evidence for anthropogenic activity, except for the last few decades since ca. 1955, though the region has a long history of mobile pastoralists. For explanation of decadal-scale changes in the regional vegetation cover, the Artemisia /Chenopodiaceae (A/C) pollen ratio proved to be a reliable indicator of effective moisture availability. Using available fossil and published instrumental data our study suggests a link between the North Atlantic warmer/colder temperatures and higher/lower atmospheric precipitation (or moisture availability) in southern Siberia at multi-decadal to centennial scales. [ABSTRACT FROM AUTHOR]

The history and continuity of lowland woodlands in Central Europe is closely connected with human activities. We studied a small wetland situated directly in a low-elevation oak-dominated woodland to evaluate the history and impact of humans on an oak woodland in south-eastern Slovakia. We used different proxies to obtain evidence of woodland history spanning at least 8,500 years. Pollen, diatom and physical analysis, including micromorphology, were used to study infill sediments and to determine the processes causing the influx of material into the wetland basin from its surroundings. The oak-dominated woodland community occurred throughout the Holocene, but its detailed history is impossible to trace because of reverse chronology caused by mixing of deposits. The stability of the oak woodland was determined by anthropogenic disturbances such as grazing. These disturbances are indicated by pollen taxa, signals of soil erosion in the deposits, and local development of the wetland that acted as drinking and hemp retting basin. The recent decline of human pressure has led to gradual changes in the species composition of the wetland itself (shrub encroachment) and of understory of the surrounding oak woodlands. [ABSTRACT FROM AUTHOR]

In this study, late Holocene vegetation, climate and human impacts were investigated using multiproxy data-pollen percentages, pollen accumulation rates (PAR), humification and loss-on-ignition (LOI)-measured from peat sediments from Daiyun Mountain, southeast China. A stratigraphic chronology was established on the basis of four radiocarbon dates. The 4,350 year sequence of vegetation history and climate change exhibits three distinctive stages: (1) 4,350-1,000 cal bp, during which the vegetation was dominated by evergreen forests mainly composed of broad-leaf trees, indicating a warm and wet climate; (2) 1,000-550 cal bp, during which the climate was thought to be cool and dry, based on a decrease in pollen percentages and the PARs of trees, shrubs and wetland herbs, and an increase in the pollen percentage and PAR of dry land herbs, as well as high overall LOI values; and (3) 550 cal bp to modern times, during which higher pollen percentages of dry land and wetland herbs, along with low pollen percentage and PAR of trees and shrubs, as well as low absorbance and LOI values, suggest relatively cooler but wetter climate conditions. In addition, major climatic events, such as the warm period from ad 670-960, the Medieval Warm Period ( ad 1050-1520) and the Little Ice Age ( ad 1580-1850), could be identified within the peat sediments in this study, with climatic conditions at these times being characteristically warm and wet, warm and dry, and cold and wet, respectively. Pollen signals indicate significant human impact since 1,000 cal bp, which may be linked to the development of the local porcelain industry and a rapid increase in the population in the study region. [ABSTRACT FROM AUTHOR]

Pollen and charcoal records of a 150 cm long lake sediment core from Taibai Lake in the middle reach of the Yangtze River reveal seven major changes in regional vegetation over the last 1500 years. During the period c. ad 480–710, evergreen broadleaved forest dominated by Castanopsis/Lithocarpus and evergreen oaks occurred in the Taibai Lake catchment. From c. ad 710 to 1050, the vegetation shifted to a mixed conifer and broadleaved forest, with Pinus expanding at the expense of Castanopsis/Lithocarpus. Between c. ad 1050 and 1320, evergreen broadleaved forest reoccupied the studied area. From c. ad 1320 to 1650, the area of primary forest decreased markedly with synchronous reduction in broadleaved trees and Pinus. Between c. ad 1650 and 1740, the biomass declined rapidly, while secondary Pinus forest began to expand. During c. ad 1740–1950, forest extent increased slightly compared with the previous stage, but the landscape was still secondary forest with the minimum proportion of broadleaved trees. After c. ad 1950, the biomass in the surrounding area was very low, with vegetation types similar to that at present (secondary Pinus forest and mixed conifer and broadleaved forest). A detrended correspondence analysis (DCA) with 125 samples and 34 main pollen types is used to separate human and climatic impacts on vegetation. Then, the pollen assemblage, DCA, charcoal record, and magnetic susceptibility are combined to discuss the key factors inducing these vegetation changes. The vegetation changes were mainly controlled by the climatic changes, with the weak impacts of human activities before c. ad 1320. Since then, the intensity of human influences on vegetation increased gradually, entering a transitional period of main controlling factors of vegetation changes from nature to human activities. After c. ad 1740, the vegetation changes were chiefly controlled by human activities, and the climatic signal was weak. [ABSTRACT FROM AUTHOR]

A high-resolution peat profile from the vicinity of Saariselkä (68°25.24′N, 27°25.19′E), a large tourist centre in northern Finnish Lapland, was sampled continuously at near annual resolution to a depth of 22 cm in order to interpret the changes in pollen assemblages and vegetation resulting from human interference and reindeer herding. Fifteen AMS dates were wiggle-matched with the atmospheric 14C calibration curve. The resulting age-depth model allows the calculation of pollen accumulation rates (PAR grains/cm² per yr), which, in turn, enables the fine-scale human impact to be interpreted on much better grounds than would be possible with the classical pollen percentages approach. Results indicate that increasing tourist numbers since the building of the Saariselkä resort in 1950 are not seen in the pollen diagrams. Only a slight, although clear, increase in the pollen taxa of disturbed sites (mainly Gramineae with some herb pollen taxa) can be detected from the PAR diagram after the 1950s, along with a decrease of Pinus pollen following the clearance of the ski slopes in the 1970s. Principal components analysis (PCA) of fossil pollen spectra and modern pollen analogues obtained from both natural and human-disturbed sites confirms that human interference that has affected the vegetation around Saariselkä is not visible in the pollen record to the degree that might have been expected. This is interpreted as resulting from the considerably different nature of human impact at Saariselkä, where the infrastructure is fully developed and weed species are efficiently removed. The remarkable growth of reindeer population in the area during the 1980s, however, can be observed in the peat profile through an increase in the number of coprophilous fungal spores (Podospora, Sporormiella). This increase in fungal spores occurs simultaneously with a decrease in Betula pollen, which is interpreted to be a consequence of reindeer foraging the young Betula trees and seedlings. [ABSTRACT FROM AUTHOR]

Pollen, plant macrofossil and charcoal records from two neighbouring crater lakes (Lake Wandakara and Lake Kasenda) in lower montane (altitude ~1200 m) western Uganda (0.5°N, 30°E) reveal major changes in local and regional vegetation over the last 1200 years, which can be related to regional variations in climate (especially effective precipitation) and human impact. The biological signals are supplemented by evidence from physical sedimentary analyses (magnetic susceptibility, loss-on-ignition, dry mass accumulation rate) for major catchment changes in a wider regional context. From AD 750 to 900, medium-altitude moist forest existed around Lake Kasenda, which was largely replaced by grassland by AD 1000, coincident with evidence for increased catchment erosion and fire events, linked to human impact during a brief arid phase. Despite wetter conditions from AD 1000 to 1200 and in the 1400s, grassland prevailed around both sites until c. AD 1700—1750, with increased catchment disturbance from AD 1600 to 1700, shortly before the abandonment of major regional settlements and a switchto dispersed homesteads more reliant on pastoralism. Bothsites show the return of semi-deciduous and swamp forest from c. AD 1700 to 1800, withtree and shrub pollen remaining high until the most recent times. Pollen assemblages reveal increasingly clear human impact on local and regional vegetation in the twentieth century, which obscures any climate signal. Pollen signals may not be sensitive to all climatic fluctuations (e.g., late eighteenth-early nineteenth-century aridity), but appear to record the varying impacts on vegetation communities of both climate and human activity over long timescales. Other proxies should be analysed to disentangle further the relative importance, and interactions, of these two major drivers of environmental change in tropical Africa in recent millennia. [ABSTRACT FROM AUTHOR]

A late-Holocene vegetation record is presented from the southwest coast of New Caledonia. Lac Saint Louis is a freshwater swamp at 3 m a. s. l. adjacent to the River Coulee delta. Pollen analysis, charcoal analysis, radiocarbon dating and stratigraphic analyses have been used to reconstruct the vegetation and sedimentary history of the swamp. The sediment record commences at 6000 BP and reflects rapid floodplain development associated with postglacial sea-level rise. This rapid accumulation of sediment ceased around 5500 BP and the site became a freshwater swamp. From 5500 to 3000 BP the pollen record reflects several aspects of this coastal landscape; coastal forest, the swamp surface and the adjacent mangrove zone. At 3000 BP charcoal levels increase significantly in conjunction with abrupt changes in the pollen record. Mangrove pollen declines and pollen indicative of coastal forest is replaced by pollen indicative of coastal savanna. These changes coincide with the commencement of the archaeological record in New Caledonia and mirror similar changes in other late-Holocene records elsewhere on the island, and are interpreted as representing human impact. Yam terraces surrounding Lac Saint Louis may have been built around 2000 BP based on mineral magnetic measurements and charcoal accumulation. The decline in mangrove vegetation adjacent to site may be the result of a late-Holocene fall in sea level. Increased sediment accumulation along the coastal foreshore as a result of forest clearance in the River Coulee's catchment, however, is also considered. [ABSTRACT FROM AUTHOR]

Pollen and charcoal analysis of sediment cores from two lakes in the highlands of northern Ethiopia provide evidence that the vegetation has changed in response to human impact during the last 3000 years. The natural, pre-disturbance vegetation of the area was Podocarpus-Juniperus forest. At about 500 BC, following Semitic immigration to northern Ethiopia, the forests were cleared and replaced by a secondary vegetation of Dodonaea scrub and grassland that persisted for 1800 years. Grasslands were dominant from about AD 1200 to 1400, probably as a result of further intensification of grazing, perhaps exacerbated by drought. Juniperus forest, with Olea and Celtis, then expanded from AD 1400 to 1700, possibly because of drought-induced depopulation followed by increased rainfall. Deforestation and soil erosion has again intensified during the last three centuries. Since forest regrowth was possible after 1800 years of human impact, northern Ethiopia should again be capable of supporting forest under appropriate land management. [ABSTRACT FROM AUTHOR]

The Viking Age town of Birka, which existed between AD 750 and 975, on the island of Björköin the Mälar archipelago of the Baltic Sea, is known as the oldest centre used for large-scale international trading in Sweden. Birka had a strong defence: town rampart, hillfort and a water palisade. Studies of lithology, and micro- and macroremains in a sedimentary sequence accumulated offshore from Birka, outside the water palisade, revealed a stratigraphically distinct refuse stratum, referred to as the Birka Layer. We argue that the bulk material of the Birka Layer emanates from human activities in the town, e.g., latrine cleanings, cuttings of shore vegetation, cleaning of ditches and storage areas, and domestic animal dung. Organic remains from vegetation and animals, deposited during activities on the ice offshore from the town, e.g., winter markets, may also have contributed to the composition. The material constituting the Birka Layer started to accumulate after the construction of the protecting water palisade. In the Birka Layer and the underlying clay gyttja, there seems to be a succession of five activity phases recorded during the Birka period. After the initial establishment of the town, an expansion took place, followed by a retrogression. The most intense phase with culminating activities is registered prior to abandonment of the site, which approximately coincides with the onset of the extended final isolation process of Lake Mälaren (AD 1000-1300). The sailing routes to Birka from the south and east became too shallow and were finally cut off by the emerging thresholds. After the abandonment of Birka, the town area was utilized for cultivation and cattle-breeding. [ABSTRACT FROM AUTHOR]

We analysed pollen and charcoal in a lake-sediment core from Laguna Zoncho, a small mid-elevation lake in southernmost Costa Rica. The record provides evidence of 3000 years of human occupation, forest clearance, agriculture and fires in the area. Laguna Zoncho is located 2 km from the Las Cruces Biological Station, and results are relevant to understanding the likely extent of prehistoric disturbance within the premontane rain forests of this biological reserve. Pollen grains of Zea mays in the basal sediments of the Zoncho core constitute the oldest botanical evidence of maize cultivation in southern Costa Rica. The presence of maize pollen in almost every sample analysed indicates nearly continuous occupation of the lake basin for 3000 years. Charcoal abundances and percentages of pollen grains and spores of forest and disturbance taxa fluctuate strongly downcore, reflecting variable intensities of past human impact. Forest clearance and burning by indigenous people were most marked between 3240 and 460 cal. yr BP. Sediments deposited subsequently indicate forest regeneration and few, if any, fires. However, indigenous cultivation of maize continued on a small scale until European settlement in the twentieth century. [ABSTRACT FROM AUTHOR]