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The main objective of this study was to examine the spatial distribution patterns of aquatic invertebrates in an environment characterized by significant anthropogenic stress. During the entire research period, at all the sites, we noticed 72 taxa of zooplankton and 30 taxa of macroinvertebrates. Variation partitioning analysis reveals that the assemblages of planktonic organisms are much more determined by the time of sampling rather than by the site, in contrary to macroinvertebrates where the sampling time was only slightly more responsible for the composition of the benthic communities than the site. Spatial distribution of aquatic organisms in a small lowland river under strong anthropopressure shows significant deviations from the expectations of the River Continuum Concept (RCC). The benthic macroinvertebrate and littoral zooplankton communities exhibited a strong association with local site conditions, while, in contrast, pelagic zooplankton exhibited a strong dependency on drift and its production in the upper reaches of the river, leading to relatively consistent compositions downstream despite the highly altered river environment. To improve the biodiversity values and ecological state of a river, restoration treatments of bed and shore zones are required. [ABSTRACT FROM AUTHOR]

Mangrove wetlands are vulnerable coastal ecosystems that provide critical habitats for aquatic life. Tai O is a popular tourist village on Lantau Island, Hong Kong, which is surrounded by mangrove wetlands with rich biodiversity; and this village is also famous for its traditional stilt houses. However, the untreated municipal sewage from some stilt houses is directly discharged into nearby tidal channels, potentially threatening health of the adjacent mangrove wetlands. In order to evaluate the anthropogenic impact on these wetlands and identify the potential sources of their pollution, this study aimed to evaluate spatial (at the sampling points) and temporal (during weekdays and weekends) differences in the quality of their tidal water, and examine relationships between the water quality and the density of the stilt houses. The results indicated that the water quality was worse during weekends. The ammonia concentrations in most samples exceeded the limits of the Hong Kong Water Quality Objectives, China's Sea Water Quality Standards, and even the U.S. EPA criterion for fish reproduction. This high ammonia input could potentially adversely affect the mangrove ecosystem, underscoring the need for further comprehensive studies. Moreover, some of the weekend water samples had lower dissolved oxygen levels and were polluted by phosphate. Our Principal Component Analysis revealed that water quality was correlated with stilt house density, suggesting that anthropogenic inputs of untreated sewage was the major source of pollution. These findings highlight that nutrients released from human activities, particularly ammonia and phosphate, must be controlled for a better protection of mangrove wetland ecosystems. [ABSTRACT FROM AUTHOR]

In the High Middle Ages, a wave of landscape transformation which originated in western Europe swept across the east-central part of the subcontinent. In the Czech Republic, this happened during the 13th century and it had the same environmental attributes as in the rest of Europe-a considerable increase in population, vast deforestation resulting in a rapid increase in soil erosion, irreversible changes in forest species composition and overall formation of a cultural landscape. In the Czech Republic, the dynamics of such a radical change are poorly understood because it would require detailed archaeological, historical and palaeoecological insight into developments during the Early Middle Ages-a demand that is mostly not met. The aim of this paper is to fill in this gap. Archaeological and historical data from three early medieval strongholds located in central Bohemia, at Libice nad Cidlinou, Stará Boleslav and Hradišťko, are summarized and evaluated. The first two sites represent well-known political and religious centres of the early Czech state in the 10 to 11th centuries, while the last was of secondary importance. These archaeological sites have radiocarbon dated pollen and plant macrofossil evidence from oxbow sedimentary sequences which are situated in the immediate vicinity of the strongholds. The issue of fluvial transport of pollen and macrofossils is also discussed. Both pollen and macrofossil data from Hradišťko show surprisingly small impact of the stronghold on the forested alluvial environment. The vicinity of Stará Boleslav was intensively affected by human activity only during the later 11th century. It has not been possible to trace any impact of the foundation of the stronghold at Libice nad Cidlinou on the landscape. Medieval landscape change began before the 13th century in some places, as shown by the data from Stará Boleslav. [ABSTRACT FROM AUTHOR]

Today, the settlement site of Luokesa 1 (L1) lies under water at the northern edge of Lake Luokesa in the Baltic Uplands, south-eastern Lithuania. Its 60 cm-thick Late Bronze-Early Iron Age cultural layer lies on top of lake marl. During excavations in 2008 and 2009, core samples at L1 were taken for the purpose of multidisciplinary investigations. From this material, five on-site pollen diagrams were created in parallel with geo-archaeological investigations and the examination of the botanical macro-remains. Two of these cores mainly comprised the cultural layer, another two consisted largely of the underlying lake marl and the fifth contained primarily the transition from the lake marl to the cultural layer. The chronological sequence was established through 11 AMS dates. The woodland history, starting from the Late Atlantic period, was recorded. The Quercetum mixtum values are quite low in the Subboreal, with the coniferous forest consisting mainly of Pinus and, though significantly less, Picea. At the transition to the cultural layer (Subatlantic) the pollen curves are highly variable, showing peaks in the curves for Betula and Alnus. Pollen from aquatic plants is also present. Changes in riparian vegetation and turbulent sedimentation conditions are to be expected and can be explained by a drop in the water level. As L1 was located on damp ground at that time, water influxes alternating with dry episodes were observed. In the area around L1 the sedge belt was less pronounced, and riparian woodland extended all the way to the shores of the lake. Pollen analyses of four sheep/goat dung samples provide information on the grazing season and pasture location of these domestic animals. The paper also discusses layer formation processes such as water level fluctuations and hiatuses. [ABSTRACT FROM AUTHOR]

Lake Luokesa lies in the eastern part of Lithuania and is part of a region of lakes formed by the Scandinavian ice-sheet and its melt waters during the last glaciation. During the Late Bronze-Early Iron Age transition, between 625 and 535 cal BC, a lakeside settlement with an onshore palisade was built on the platform of a carbonate bank. A total of five profiles, each comprising an organic occupation layer and lake sediments at its bottom and top, were examined micromorphologically. In this paper, natural and anthropogenic processes that led to the formation of the individual layers are presented; their possible origins are reconstructed and then discussed and compared to lakeside settlements of the circum-alpine region. This includes the emergence of lake marl, accumulation of organic layers in the settlement area as well as their decomposition, erosion and trampling features and inwash of sand through runoff from the hinterland. Due to the accumulation of the up to 60 cm thick culture layers in waterlogged environments, indications of seasonal deposition cycles could be identified. [ABSTRACT FROM AUTHOR]

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Human-induced land cover changes are causing important effects on the ecological services rendered by mountain ecosystems, and the number of case-studies of the impact of humans on soil erosion and sediment yield has mounted rapidly. In this paper, we present a conceptual model that allows evaluating overall changes in erosion regulation after human disturbances. The basic idea behind this model is that soil erosion mechanisms are independent of human impact, but that the frequency-magnitude distributions of erosion rates change as a response to human disturbances. Pre-disturbance (or natural) erosion rates are derived from in situ produced Be concentrations in river sediment, while post-disturbance (or modern) erosion rates are derived from sedimentation rates in small catchments. In its simplicity, the model uses vegetation cover change as a proxy of human disturbance. The erosion regulation model is here applied in two mountainous regions with different vegetation dynamics, climatic and geological settings: the Austro Ecuatoriano, and the Spanish Betic Cordillera. Natural erosion benchmarks are necessary to assess human-induced changes in erosion rates. While the Spanish Betic Cordillera is commonly characterized as a degraded landscape, there is no significant difference between modern catchment-wide erosion and long-term denudation rates. The opposite is true for the Austro Ecuatoriano where the share of natural erosion in the total modern erosion rate is minimal for most disturbed sites. When pooling pre- and post-disturbance erosion data from both regions, the data suggest that the human acceleration of erosion is related to vegetation disturbances. The empirical regression model predicts human acceleration of erosion, here defined as the ratio of post-disturbance to pre-disturbance (or natural benchmark) erosion rate, as an exponential function of vegetation disturbance. This suggests that the sensitivity to human-accelerated erosion would be ecosystem dependent, and related to the potential vegetation cover disturbances as a result of human impact. It may therefore be expected that the potential for erosion regulation is larger in well-vegetated ecosystem where strong differences may exist in vegetation cover between human disturbed and undisturbed or restored sites. [ABSTRACT FROM AUTHOR]

This paper aims to reconstruct the vegetation history of a middle mountain – the Morvan (Burgundy, France) – since the Neolithic (i.e. 7000 years). The results of palynological and non-pollen palynomorphs (NPPs) analysis performed on 10 peat cores document the main phases of human agro-pastoral practices and natural resources management which drove the formation of the cultural landscape of the Morvan Massif over time. To document the history of human activities at a regional scale, particular attention was given to the determination, the characterization and the graphical depiction of phrases of human impact. Both the quantification of the impact of human pressure and the chronological uncertainty of the different phases identified by pollen and NPP analysis were taken into account. This study reveals a clear human presence during periods that were formerly poorly documented, such as the onset of the Neolithic period, the Bronze Age, the early Iron Age and the early Middle Ages. It also sheds new light over periods for which there is better archaeological and historical knowledge, such as the widespread occupation of the massif in the late Iron Age, the cultivation of chestnut from the 11th to the 16th century and the impact of modern firewood exploitation on the forest. [ABSTRACT FROM AUTHOR]

This paper presents the results of comparative sedimentological and geochemical analysis of the mire at Sânpaul, Round Lake (Kerek-tó). The palaeoecological site is situated in the western foothill area of the Eastern Carpathians in Romania. The primary objective of this study was to analyse the accumulation of major and trace elements in a 7500 year-long peat and lake deposition. The concentrations of 13 elements were determined by using handheld XRF. This paper presents the results of a multidisciplinary study, for which the principal aims were to examine the long-term relationship between land degradation in the Homoród Hills using various palaeoecological techniques, primarily comparative geochemical analyses. The PCA of elemental concentrations suggests that Round Lake is mainly controlled by the input of inorganic mineral matter and the LOI550 of peat. However, some elements are influenced by biological processes of vegetation and groundwater. Geohistorical studies compared with vegetation changes and elemental distribution helped the detection of erosion phases in the level of 12 prehistoric cultures.

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An important feature of the ongoing debate about the acceptance of the Anthropocene as a formal chronostratigraphic unit with the same rank as the Holocene (epoch) has been either the existence or the lack of a Global Stratotype Section and Point (GSSP). In addition, the utility of the Anthropocene as a stratigraphic unit has also been questioned. In this paper, it is proposed that the discovery of the GSSP may not be a major problem and could only be a matter of time. However, the term Anthropocene itself, defined on the basis of the stratigraphic expression of human activities (e.g. large-scale agriculture and land clearance, accelerated release of greenhouse gases to the atmosphere) may significantly impact the current stratigraphic framework guided by the International Commission on Stratigraphy (ICS). Indeed, the formal usage of this term can not only lead to stratigraphic and terminological inconsistencies but can also influence the future development of the established chronostratigraphic scheme. These points should be considered by the ICS Anthropocene Working Group before making a final decision. The stratigraphic status of the Anthropocene, however, is a formal issue that should not affect current and future research on human-induced environmental and sedimentary changes, including their stratigraphic imprint. The message is twofold: leave the formal chronostratigraphic aspects to the ICS, and keep producing and organizing knowledge independently of the formal debate. Doing so would require the development of a parallel and likely transitory chronological system without formal stratigraphic value, from which the term Anthropocene would be, at least temporarily, excluded. [ABSTRACT FROM AUTHOR]

The investigated area near Flintbek (Schleswig-Holstein, Northern Germany) was used as a burial ground from the Neolithic until the Iron Age. Due to modern agriculture, the above-ground funerary monuments have been destroyed. Rescue excavations from 1976 to 1996 recovered the archaeological remains. In addition to the archaeological reassessment of the findings, further scientific analyses were carried out. The results of the charcoal analyses are presented in this paper. The overall spectrum of wood species represents the typical species composition of mixed oak forests. Over the whole investigated time span (Neolithic-Iron Age) these species alternate with a second group of taxa: species benefiting from better light conditions. In times of intensive human impact, these light-demanding taxa gained considerable importance, showing the opening of the wooded landscape. In phases with less human impact, a regeneration of mixed oak forest is detectable. For the Neolithic it was possible to develop a more detailed picture of wood usage based on 162 radiocarbon dates of 106 samples. These illustrate considerable changes during the Neolithic, which resulted in a varied pattern of open land and closed forest influenced by human presence and land use. Another important aspect of the Flintbek area is the handling of samples deriving from different contexts. While charcoal samples related to fire usage or grave constructions contain only slight contamination, samples from fillings (pits, burial layers) are characterized by charcoal dating being either too old or even too young for the archaeological context. [ABSTRACT FROM AUTHOR]

The aim of this paper is to provide comprehensive analysis of channel changes (horizontal and vertical movements of channel boundaries due to water flow and sediment transport interactions) in rivers across Russia. Evidences from channel transformations indicate that largest Russian rivers (Volga, Oka, Amur) are sensitive to mostly human impacts (reservoir construction, in-channel quarries, land disturbance and bank fortification). Channel changes in the Severnaya Dvina, Lena, Pechora and Ob Rivers over the past 100 years have been driven mainly by natural factors at the river scale, whereas some reaches were influenced by human interventions (including single reservoirs). Reservoir construction is probably the most extended influence on morphodynamics of the largest rivers of Russia, but the influence of other controls resulting in channel boundary movement and channel pattern changes could also be detected. [ABSTRACT FROM PUBLISHER]

Tidal freshwater wetlands (TFW) are situated in the upper estuary in a zone bordered upstream by the nontidal river and downstream by the oligohaline region. Here, discharge of freshwater from the river and the daily tidal pulse from the sea combine to create conditions where TFW develop. TFW are often located where human population density is high, which has led to wetland degradation or destruction. Globally, TFW are largely restricted to the temperate zone where the magnitude of annual river discharge prevents saline waters from penetrating too far inland. The constant input of river water delivers high loads of sediments, dissolved nutrients, and other suspended matter leading to high sedimentation rates and high nutrient levels. Prominent biogeochemical processes include the transformation of nitrogen by bacteria and immobilization of phosphate. A diverse, characteristic vegetation community develops which supports a rich fauna. Biotic diversity is highest in the high marsh areas and decreases in the lower levels where tidal inundation is greatest. Benthic fauna is rather poor in diversity but high in biomass compared to other regions of the estuary. Global climate change is a threat for this system directly by sea level rise, which will cause brackish water to intrude into the fresh system, and indirectly during droughts, which reduce river discharge. Salinity will affect the presence of flora and fauna and facilitates sulfate reduction of organic matter in the soil. Increased decomposition of organic matter following saltwater intrusion can result in a lowering of wetland surface elevation. The papers assembled in this issue focus on how these tidal freshwater wetlands have changed over recent time and how they may respond to new impacts in the future. [ABSTRACT FROM AUTHOR]

We present here the results of pollen analysis of one sequence of about 60 cm length, originating from sediments of Hautes-Fagnes peat bogs (Eastern Belgium). 49 pollen spectra reflect the local vegetation evolution and also the evolution of the forestry surroundings. The results of these investigations are correlated to the results of other studies previously carried out in the area. Our data suggests human occupation and intensive land use in the region. Aspects regarding a Roman/Merovingian paved road, at present covered by a layer of peat that can reach 1 m thickness in some places, are also debated in the present paper. The origin and functionality of this paved road have not yet been fully elucidated, despite the studies already performed. [ABSTRACT FROM AUTHOR]

The lowland heathlands of southern England comprise ca. 14 % of the total area of this habitat in Europe yet their history is poorly understood. This paper presents the first detailed palaeoecological evidence (combining palynological, microscopic charcoal and radiocarbon data) relating to the origin and long-term dynamics of heathland vegetation in southern England. Valley peat sites, situated on the Lower Greensand Group (coarse-grained sandstones) at Conford (Hampshire) and Hurston Warren (West Sussex) have been investigated. The sequence from Conford indicates the unusually late survival of Pinus sylvestris (to as late as ca. 6050 cal. b.p.) in southern England. This is attributed to edaphic factors and, after ca. 7050 cal. b.p., to frequent fires. After intervening phases of dominance by deciduous woodland, heathland vegetation became established in the proximity of both sites in the Late Bronze Age (ca. 3000 cal. b.p.) with increases in indicators of grazing and burning demonstrating an association between the development of heathland and human activity. Thereafter, the pollen and charcoal records show that the vegetation remained in a dynamic state as the scale and nature of human activity varied through time. Major expansions in the extent of heathland occurred relatively recently; after ca. 1450 cal. b.p. at Hurston Warren and after ca. 850 cal. b.p. at Conford. A review of the palaeoecological evidence suggests that the most intense use and greatest coverage of heathland in southern England probably occurred during the medieval to post-medieval periods. [ABSTRACT FROM AUTHOR]

This paper presents the results of a sedimentological study performed to characterize the 'Bosco Pantano di Policoro e Costa Ionica Foce Sinni' coastal system, in Basilicata (southern Italy), as part of the PROVIDUNE LIFE Project. The study was focused on the morpho-sedimentological characterization of both the emerged and submerged sectors of the beach system developed along a 3.5 km-long segment of the Ionian coast. A multitemporal comparison of historical aerial photos of the studied coastline concerning the last 100 years was executed. A geomorphological survey was carried out along 36 topographic profiles (each up to 200-m long); these were coupled with bathymetric profiles, reaching a depth of -13 m. Both topographic and bathymetric profiles were measured on three occasions (July, October, December 2010). Textural and compositional analyses of sediments were also performed. The results of this study were synthesized in a series of maps illustrating a schematic geological outline of the study area, a reconstruction of the Sinni river course and shoreline changes from 1908 to 2010 (1:2,400 scale), significant topographic (1:1,300 scale) and bathymetric (1:5,000 scale) profiles, three bathymetric charts (1:31,000 scale) and morpho-sedimentological features of both the coastal and nearshore sectors (1:15,000 scale). This study provides a geological background that is crucial for any intervention planning, as well as for any coastal zone management projects. The results should be also used in order to protect coastal habitats, which is the ultimate goal of the LIFE project. [ABSTRACT FROM AUTHOR]

Integration of pollen data from both marine and terrestrial cores contributes to the understanding of the timing of the climatic and human forces that shaped the cultural landscapes in the Italian peninsula. This paper focuses on the relation between natural and human landscapes, and the development of the cultural landscape from the Bronze Age to the medieval period and modern times. Two records were studied within independent projects, first the marine core RF93-30, from the central Adriatic, with a sediment source area including the Po valley and which spans the last 7,000 years, and secondly, material from the site of Terramara di Montale, a Bronze Age settlement on the Po plain, which was occupied from approximately 3550-3200 cal. b. p. The original chronology of the marine core was developed by using the magnetic inclination of the secular variation record and two C dates carried out on benthic and planktic foraminifera at depths of 527 and 599 cm. Its pollen record shows a gradual irreversible trend towards increasing aridity since 5700 cal. b. p. and, just after around 5100 cal. b. p., a Picea decline and a Quercus ilex type increase indicate less cool conditions. Human impact introduces rapid changes, such as the decrease of Abies alba, thinned by the reduction of precipitation and further cleared before or during the Early Bronze Age, followed by the fall of oaks. The latter started after around 3900 cal. b. p., and became evident at around 3600 cal. b. p. The gradual increase in signs of open landscape and woodland clearance correspond to the onset of Middle Bronze Age settlements in the Po valley, and to the development of the cultural landscape in the region. The impact of the terramare people includes woodland management by coppicing, and division of the territory into a patchwork of pastures and fields. Dry environments are indicated mainly by Cichorioideae, resulting from the continued human pressure, and these spread since the Recent Bronze Age. Of the possible causes for the decline of the terramare, we suggest that climate would have been less important in the decline than in the onset phases. The later cultural landscapes are mainly indicated by the trends of the Olea, Juglans and Castanea (OJC) records, besides those of cereals. At around 700 cal. b. p., the 'chestnut landscape' spread while modern times are shown by the finds of Zea mays. [ABSTRACT FROM AUTHOR]

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The location of the area of the two communes in the interference space of Getic Subcarpathians with Făgăraş Mountains imposed along time a variety regarding the land use. Because in the last decades it has produced the accentuated spatio-temporal dynamics of different categories of the land use from this area, the present paper aims to analyze which are the factors upon which these modifications were based, and especially what type of mark has been left in the quality and functionality of the environment. The evaluation modality of the land use dynamics due to the human impact, consists in the application of some synthetical indexes which characterize the degree of environmental transformation from a historical perspective. The application and analysis of the indexes in two different periods, 1980 and 2005, have been possible by obtaining and comparing the data and information from different sources (digitization on topographical maps and orthophotomaps, statistical data, informations from the data set geo-spatial and Corine Land Cover). This analysis lead to the spatialization and intensity of the transformations induced by the dynamics of land use changes in the Subcarpathian rural landscape, as well as the establishment of landscapes' artificiality from this area. [ABSTRACT FROM AUTHOR]

As with most Italian rivers, the Reno River has a long history of human modification, related also to morphological changes of the lower Po River since Roman times, but in the last decades, significant land use changes in the headwaters, dam construction, torrent control works and extensive bed material mining have caused important channel morphology and sediment budget changes. In this paper, two main types of channel adjustment, riverbed incision and channel narrowing, are analysed. Riverbed degradation is discussed by comparing four different longitudinal profiles surveyed in 1928, 1951, 1970 and 1998 in the 120 km long reach upstream of the outlet. The analysis of channel narrowing is carried out by comparing a number of cross-sections surveyed in different years across the same downstream reach. Field sediment transport measurements of seven major floods that occurred between 2003 and 2006 are compared with the bedload transport rates predicted by the most renowned equations. The current low bedload yield is discussed in terms of sediment supply limited conditions due to land use changes, erosion-control works and extensive and out of control bed material mining that have affected the Reno during the last decades. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper presents the first quantitative past land cover reconstructions for northern Poland using the Landscape Reconstruction Algorithm (LRA), interpreted alongside traditional percentage pollen data and historical sources. These data are used to evaluate the impact of cultural change on past vegetation and land-use in northern Poland during the last 2000 years. Vegetation change and land-use are apparent corresponding to the late Roman Iron Age (1st to 3rd centuries), Migration Period (4th–7th centuries), early Medieval (8th to early-13th centuries) and late medieval (early-13th to mid-15th centuries). The Roman Iron Age is characterised by significant land cover estimates for meadowland, likely part of a broad spectrum agricultural strategy. Widespread depopulation and woodland regrowth characterise the Migration Period, followed by the progressive clearance of woodland from the 7th/8th centuries corresponding to Slavic colonisation. Polish control of the region from the mid-10th century is accompanied by intensification in agricultural land-use. However, archaeological evidence for increasing settlement instability during the 11th/12th centuries is not obviously apparent in the palynological data. This likely reflects the sporadic nature and uneven impact of conflict, but also the difficulty in resolving short-term events in the palynological record. Significant woodland clearance occurred prior to the crusades, with the consequence that there is no clearly identifiable horizon of significant landscape change associated with the arrival of the Teutonic Order. However, large tracts of woodland survived in sparsely populated frontier zones and in areas with poor agricultural soils, managed as part of an extensive provisioning network covering the Teutonic Order's state. [ABSTRACT FROM AUTHOR]

Abstract In the present paper we report on the only known example of a hummocky meadow in Poland. The area of the Hala Długa in the Gorce Mountains is a hotspot of complex geomorphic edge effects that have been widely studied in relation to human impacts and forest disturbances. Applying an interdisciplinary approach, we aimed to study the geomorphic activity in edge conditions between two contrasting ecosystems, a high-mountain meadow and a forest. Several methods were applied: geomorphic mapping, radiocarbon dating, soil analysis, geomorphometry, wood anatomy, and investigations of historical maps. These methods enabled us to reconstruct the history of the Hala Długa over the past ca 300 years, and to evaluate geomorphic activity and soil dynamics in this area. The treethrow pit-mound microtopography (hummocky meadow, Buckelwiese) of this area was formed under forest conditions, but due to long-term human impacts linked to sheep grazing and mowing, was preserved as a distinct topography for at least 100 years. While this topography was still clearly visible in the 1950s, when it was first reported, it is currently gradually disappearing under trees that have formed a belt around the study area. Soils of the study site were disturbed by tree uprooting, with many key features identified during the soil profile analysis: spots of coarse partly oriented sandstone fragments in pits, patches of organic matter in the metamorphic B horizon, and a large number of root remnants and pieces of charcoal in different parts of treethrow mounds and pits. We suggest a non-linear or even polygenetic soil evolution due to altered vegetation and disturbance regimes. The evaluation of wood remnants revealed that the majority of uprooted tree species were Picea abies (L.) H. Karst and Larix decidua Mill. We conclude that in the Gorce Mountains geomorphic edge effects can form hotspots of geomorphic activity driven by human impacts, natural disturbances, and the specific hydrological regime in the highest parts of the massif. Highlights • Treethrow pits and mounds persisted for at least 100 years as a high-mountain meadow. • We report on the only known hummocky meadow location in Poland. • Geomorphic edge effects occurred due to human impact and tree uprooting. • Geomorphic edge effects influenced soil properties in the highest parts of the Gorce Mts. • The hummocky meadow cannot be completely associated with Buckelwiese topography. [ABSTRACT FROM AUTHOR]

Highlights • This research analyzes aeolian processes in an aeolian shadow induced by resorts. • The aeolian shadow is studied locally through wind, vegetation and topography data. • The regional wind direction influences the degree of wind speed change. • The erosive processes are affected by the distance to the resort and the topography. • Where erosive processes are not detected is related to the vegetation role. Abstract Structures and infrastructures can modify aeolian sedimentary dynamics as has occurred in the arid transgressive dunefield of Maspalomas (Gran Canaria, Canary Islands), where an aeolian shadow zone has been formed leeward of a tourist resort (Playa del Inglés). The aim of this paper is to analyse spatial and statistically the influences of vegetation and topography on wind flow across this shadow zone. An experiment was carried out in March 2017, collecting wind speed and direction from 5 transects with anemometers at 0.40 m height. Simultaneously, a drone flight was carried out, from which an orthophoto and digital elevation and surface models (DEM and DSM) were obtained. Distance from the resort, and the presence of vegetation were found to influence transects dominated by erosional processes. Transects that do not display erosional processes were primarily affected by the presence of vegetation. The local wind field changes at a similar distance across the transects downwind from the resorts indicating an acceleration or reattachment of the wind at this distance downwind. The vegetation role in this aeolian shadow zone could be a key to the future evolution of the area resulting in either further stabilization, or alternatively, the continued deflation of the area. [ABSTRACT FROM AUTHOR]

Climate change and human activity considerably influenced the temperate European deciduous forests through the Holocene, with the anthropogenic impacts being detected even in currently protected areas. This paper is focused on the area of the Kaluzhskiye Zaseki Nature Reserve, which contains remnants of primary broadleaved forests in central European Russia. Here, we present a new multi-proxy record including pollen, plant macrofossils, charcoal, loss on ignition and radiocarbon dating from the Mochulya peatland supplemented by 14 radiocarbon dates of charcoal fragments from soil pits in the study area. The results show that Mochulya peatland was a fen throughout the most of the time it existed. During the last 4200 cal yr BP the study area was occupied by broadleaved forests of Quercus, Ulmus, and Tilia. Picea became relatively abundant after 2300 cal yr BP. Despite the long-term human impact, vegetation fragments of these forests have persisted in the area until the present. Three main periods of deforestation and frequent fires were identified: 3700–3200 cal yr BP, 2000–1600 cal yr BP (the Early Iron Age) and 1000–400 cal yr BP (the Medieval Period). Whereas human-induced vegetation changes were apparent during the last two periods, vegetation dynamics during 3700–3200 cal yr BP were likely caused, at least in part, by climatic factors. [ABSTRACT FROM AUTHOR]

This paper describes long-term changes in human population and vegetation cover in southern France, using summed radiocarbon probability distributions and site count data as population proxies and information from fossil pollen cores as a proxy for past land cover. Southern France is particularly well-suited to this type of study as a result of previous programmes of intensive survey work and excavation in advance of large-scale construction. These make it possible to calibrate the larger scale occupation patterns in the light of the visibility issues created by the burial of archaeological sites beneath alluvial sediments. For purposes of analysis, the region was divided into three biogeographical zones (BGZ), going from the Mediterranean coast to the middle Rhône valley (MRV). All the different population proxies in a given zone show broadly similar patterns of fluctuation, though with varying levels of resolution. The long-term patterns in the different zones all show significant differences from the overall regional pattern, but this is especially the case for the non-Mediterranean middle Rhône area. Cluster analysis of pollen samples has been carried out to identify the main regional land cover types through the Holocene, which are increasingly dominated by open types over time. A variety of other pollen indicators show evidence of increasing human impact through time. Measures of human impact correlate strongly with the population proxies. A series of thresholds are identified in the population–human impact trajectory that are related to other changes in the cultural sequence. The lack of independent climate data for the region means that its impact cannot currently be assessed with confidence. However, for the later periods, it is clear that the incorporation of southern France into larger regional systems played a major role in accounting for changes in land cover and settlement. [ABSTRACT FROM AUTHOR]

Much attention has been placed on the drivers of vegetation change on the Iberian Peninsula. While climate plays a key role in determining the species pools within different regions and exerts a strong influence on broad vegetation patterning, the role of humans, particularly during prehistory, is less clear. The aim of this paper is to assess the influence of prehistoric population change on shaping vegetation patterns in eastern Iberia and the Balearic Islands between the start of the Neolithic and the late Bronze Age. In all, 3385 radiocarbon dates have been compiled across the study area to provide a palaeodemographic proxy (radiocarbon summed probability distributions (SPDs)). Modelled trends in palaeodemographics are compared with regional-scale vegetation patterns deduced from analysis of 30 fossil pollen sequences. The pollen sequences have been standardised with count data aggregated into contiguous 200-year time windows from 11,000 cal. yr BP to the present. Samples have been classified using cluster analysis to determine the predominant regional land cover types through the Holocene. Regional human impact indices and diversity metrics have been derived for north-east and south-east Spain and the Balearic Islands. The SPDs show characteristic boom-and-bust cycles of population growth and collapse, but there is no clear synchronism between north-east and south-east Spain other than the rise of Neolithic farming. In north-east Iberia, patterns of demographic change are strongly linked to changes in vegetation diversity and human impact indicator groups. In the south-east, increases in population throughout the Chalcolithic and early Bronze Age result in more open landscapes and increased vegetation diversity. The demographic maximum occurred early in the 3rd millennium cal. BP on the Balearic Islands and is associated with the highest levels of human impact indicator groups. The results demonstrate the importance of population change in shaping the abundance and diversity of taxa within broad climatically determined biomes. [ABSTRACT FROM AUTHOR]

The paper presents the results of granulometric and geochemical analyses of the superficial bed sediments of the St. George branch, one of three Danube River distributaries. Three cutoff meander reaches (the Mahmudia, Dunavăţ de Sus (Upper Dunavăţ) and Dunavăţ de Jos (Lower Dunavăţ) meanders, noted here as M, DS and DJ meanders) was selected as an example to analyse the impact of the meanders rectification on the grain size and sediment quality. The cut-offs of the meanders by navigational canals since 1984–1988 caused dramatic changes in the distribution of velocities, discharge and sediment fluxes (Popa, 1997; Panin, 2003, Tiron and Provansal, 2010, Tiron Dutu et al., 2014). The correction of the studied meanders induced different hydro-sedimentary impacts: strong modifications by acceleration of the fluxes through the artificial canals combined with dramatically enhanced deposition in the former meander in two cases (Mahmudia and Dunavăţ de Jos meanders) and slight modifications in Dunavăţ de Sus meander, where the natural channel still keeps almost its initial conveyance capacity. Sediment samples were acquired throughout several cross-sections of both natural and artificial canals of the three rectified meanders, in order to investigate the bed sediment characteristics. Grain size parameters (such as Median, Standard deviation, Skewness) show the predominance of fine fraction (silt and medium/ fine sand), relatively good sorted depending of the sample location (on the natural course of the branch, on the rectification canals or the former meanders. The statistical analysis of chemical data evidenced a high compositional variability, with concentration variation coefficients ranging between 27.4% – Sr and 178.3% – TOC (Total Organic Carbon). Generally, the highest concentrations of terrigenic compounds appear in the samples collected from the rectified natural canals. These results are validated by comparison with aDcp measurements made on each investigated profile. [ABSTRACT FROM AUTHOR]

Abstract A high-resolution sedimentological and geochemical analysis of a 21 m sediment sequence of Lake Iseo (Southern Alps, Italy) allowed for the reconstruction of the long-term flood frequency by visual identification of the event layers over the last 12 kyr cal BP. In a previous study that was undertaken on another sediment core from Lake Iseo, these layers were attributed to extreme surface runoff events. However, in this former core, large mass-wasting deposits that induce significant hiatuses did not permit a continuous record of flood events to be established. Such disturbances were absent in the core studied in the present paper. This permitted to establish a high-resolution continuous Holocene record. Based on the flood chronicle and sedimentological and XRF geochemical analyses, we found evidence of a major palaeohydrological transition at approximately 3.8 kyr cal BP, which was previously described as occurring in the western Mediterranean region. The oldest part of the record indeed presents a very low frequency of flood events (<1 flood/century), while after 4 kyr cal BP, the flood frequency increased. This pattern appears to be in agreement with other Southern Alpine paleo flood records. The transition is interpreted as a nonlinear climate response to the orbital-driven gradual decrease in summer insolation at 60°N, which together with the influence of the Mediterranean mesoscale precipitation events, is typical for the Mediterranean climate. However, the comparison of the flood record with the archaeological and historical data from the watershed suggests that human activity during the Roman period in the vicinity of the main tributaries also influenced the flood frequency. Even in a large Alpine lake and >2000 years ago, extreme precipitation events that were recorded through the sedimentation process can hence be impacted by the anthropization of the catchment area pointing the requirement of deeper studies of Earth surface critical zone pluri-millennial dynamics. Highlights • In the Alps, flood frequency is higher during period of cold and wetter climate. • A major palaeohydrological transition is observed at approximately 4 kyr cal BP. • From 2 kyr cal BP, human activity is the main driver of the SEB10 flood frequency. • In Alpine lowland lake, flood chronicle can be impacted by the anthropization. • Studying human activity is needed for flood-paleohydrological reconstructions. [ABSTRACT FROM AUTHOR]

Abstract Sandy beaches pollution by marine debris imposes arguably threats for the biodiversity, but interaction of beach bioindicators (e.g., ghost crabs) with debris has been rarely assessed. We aimed to test whether the Atlantic ghost crab Ocypode quadrata (Fabricius, 1787) misidentifies marine debris as food sources. Cigarette butts, straws, popsicle sticks, paper napkins and styrofoams were mixed into solutions with odour of natural and industrialized food. The debris were placed around burrows on beaches with distinct human pressures (low, medium and high-impact). The species interacted with marine debris more frequently in situations of lower human impact, lower prey abundance and larger burrow diameter. These results indicate that in areas with low prey availability and larger individuals, interactions between ghost crabs and debris left by beach visitors and/or transported by winds and currents to low-impact beaches are more likely to occur, mainly near to urbanized areas. Highlights • Behavioral motivations inducing ghost crabs to interact with debris were assessed. • Debris was placed around ghost crab burrows on different levels of human impact. • Ghost crab interacts with marine debris stimulated by odors from food sources. • Interaction is more frequent with larger individuals on low-impact beaches. • Ghost crab on low-impact beaches near to urban areas is exposed to solid waste. [ABSTRACT FROM AUTHOR]

After over 50 000 years of interaction between Aboriginal people and changing climates, south-western Australia's tall forests were first logged less than 200 years ago, initiating persistent conflict. Recent conservation advocacy has resulted in the protection of 49% of these tall forests in statutory reserves, providing an opportunity to implement and benefit from a growing moral consensus on the valuing of these globally significant, tall forest ecosystems. We analysed a cross-section of literature (63 papers, 118 statements) published on these forests over 187 years to identify values framing advocacy. We differentiated four resource-oriented discourses and three discourses giving primacy to social and environmental values over seven eras. Invasion sparked initial uncontrolled exploitation, with the Forests Act 1918 managing competing agricultural and timber advocacy. Following the Colonial and Country Life eras, industrial-scale exploitation of the karri forest region resulted in reaction by increasingly broad sectors of society. Warming and drying in the 21st Century emphasises the importance of intact tall forest and the Indigenous Renaissance discourse. Vesting for a more comprehensive set of values would acknowledge a new moral consensus. By analysing a cross section of 118 statements published over 187 years, we differentiate seven discourses to describe the history of forest management in the tall forests of south-western Australia. Management for a more comprehensive set of values would acknowledge a new moral consensus. [ABSTRACT FROM AUTHOR]

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In this paper the spatial and temporal responses of the Somesu Mic River (Romania) to natural and anthropogenic controls over the past 150 years are analysed, based on a series of morphometric parameters extracted from five successive sets of topographic maps and one set of orthophotos. Prior to the intensive hydrotechnical interventions of the last four decades, the river was characterized by a complex alternation of different channel types, resulting in a mixture of alluvial and mixed sinuous -meandering - sinuous anabranched - meandering anabranched reaches, each a few hundred metres to a few kilometres long. The main cause for this spatial behaviour was the local geology. Its effects were intensified by a larger scale slope, slightly higher than along a longitudinal profile with normal concavity, as a consequence of the presence of a 400m elevation knick-point located in the catchment area. A generalized maintenance of river in the floodplain perimeter during the entire interval of study (centennial scale), with local planform adjustments and lack of median scale avulsion in lateral tilting areas and along the anabranched reaches, channel lengthening and meander development during hydrological stable periods and channel shortening and increasing of natural cutoffs during periods with higher incidence of floods (decadal scale), and the incapacity of local morphologic changes resulted from human interventions to completely counterbalance general trends (decadal scale), supports the idea of decreasing the amplitude and frequency of important floods, after the end of the Little Ice Age. Channel metamorphosis by canalization, diminishing/elimination of overflows and medium-scale avulsions by changes in flow regimes (dams) and the presence of dykes in the floodplain perimeter, channel narrowing (43%) and incision (at least after 1945) downstream from dams, and probably because of in-channel gravel mining are the main anthropically induced changes along the Somesu Mic River. Even if human impact is important, both at the drainage basin scale and along the Somesu Mic River, it has only local impacts, subordinated to climate. The low level of human impact on this river could be the consequence of the higher general slope downstreamfrom 400melevation knick-point, which probably forces the positioning of its effects under an important internal threshold of the fluvial system. This boundary condition defines Somesu Mic River as an atypical river. This study supports the idea that climate has a more important role in the post-Little Ice Age (LIA) rivers' behaviour than currently accepted. Copyright©2011 JohnWiley&Sons, Ltd. [ABSTRACT FROM AUTHOR]

In Mediterranean and north-African regions, cultural trajectories have shown trends sometimes coincident with climatic changes. The mid Holocene was a period of intense changes in climate, and in environmental and cultural systems. This paper reports pollen and charcoal studies from these areas aiming at presenting how impressive cultural changes frequently coincided with critical climate oscillations. Three of the main dry events of key relevance for climatic—cultural changes were selected to discuss this topic: c. 8200 cal. yr BP, c. 6000 cal. yr BP, and c. 4200 cal. yr BP. Five examples from on-site case studies were reported: (1) Wadi Teshuinat area (Fezzan, Libya, Central Sahara); (2) Benzù cave (Ceuta mountains, Spain, NW Africa); (3) La Vaquera Cave (Central System, Spain); (4) Terramara di Montale (Po Plain, Northern Italy); (5) Arslantepe (Eastern Anatolia, Turkey). Their archaeobotanical record helps to recognise and date human presence and activity in different territories. In these examples, anthropogenic signals and comparisons with other sites could be useful to distinguish climate signal from human impact in pollen records. Charcoals are evidence of human activity in cases which are not shown by pollen. Overexploitation of thinned plant resources, including overgrazing, accelerated the evolution towards xeric conditions during drying climatic phases. Humans enforced the aridity crisis and enhanced its signal in palaeoclimatic records. Sometimes, changing exploitation strategies and movements led to the onset of new cultures. Nevertheless, the onset and decline of a culture are very different critical phases, and different agents must have been involved in their occurrence. The Bronze Age marked the environment more than the Neolithic, probably because there is a relation between improvements in knowledge, cultural changes and the evolution of complex forms of land exploitation. [ABSTRACT FROM AUTHOR]

This paper provides a synthesis of available palynological data from central Mediterranean lacustrine records, studying the causes of the important vegetation changes which occurred in the mid Holocene. They are illustrated by seven well-dated records, lakes Accesa, Mezzano, Vico, and Pergusa in Italy, Maliq, Voulkaria and Malo J. in the Balkans. A good tool for disentangling climate change and human impact is the combined interpretation of pollen percentage and concentration/influx data. Pollen concentration/influx drops are an indication of increased erosion in the catchment, mainly ascribable to forest reduction. There is no doubt that major synchronous changes could not have been caused by humans alone. Many southern European records show substantial differences between early- and late-Holocene vegetation, suggesting a general evolution from wetter to drier climatic conditions, in agreement with arid phases recognised by other, independent palaeoclimatic methods. Other pollen records show a different trend. The role of changing seasonality seems important for this region of the Mediterranean. Precipitation seasonality increased during the early to mid Holocene with winter precipitation attaining a maximum, and summer precipitation a minimum. At least three rapid climate events with changes in plant biomass are in evidence: an abrupt and short change around 8200 yr BP, another one centred around 6000 yr BP, and one soon after 3000 yr BP. From the beginning of the Bronze Age (c. 4400 yr BP in this region) human impact overlapped with a climate change, probably bipartite, towards dryness. Our results show that this aridification trend began around 8000 yr BP, and culminated around 4000 yr BP. [ABSTRACT FROM AUTHOR]

The degree of anthropogenic modification of land cover through the mid to late Holocene is of significant interest for archaeologists, climate modellers and conservation ecologists, amongst others. Spatially extensive pollen data provide an appropriate resource for the reconstruction of land-cover change; however, traditional simple methods (e.g. the AP/NAP ratio) do not provide the degree of detail required for these user groups. A range of more sophisticated methods have been developed (e.g. mechanistic model-based methods), but they require a high degree of understanding of the pollen—vegetation relationship, which is resource- and time-consuming. This paper proposes a method of intermediate complexity by which major land-cover changes can be assessed for individual sites and regions. A pseudobiomisation approach is used, in which pollen taxa are assigned to different land-cover classes (LCC), and the sum of adjusted pollen proportions for each class used to determine an LCC affinity score for individual pollen samples within stratigraphic pollen sequences. In a pilot study, data from pollen core sites from northwest Scotland and southwest England for the last 8000 cal. BP have been classified into ten land-cover classes, including predominantly wooded, semi-open and open types. Results highlight how land-cover change was punctuated rather than gradual through the mid to late Holocene, and show how habitat diversity increased after ~6000 cal. BP with the arrival of agriculture, before reaching a minimum in early modern times. This pollen-based method is potentially applicable to the reconstruction of long-term land-cover change within Europe and other temperate-zone regions. [ABSTRACT FROM PUBLISHER]

The recent climate changes combined with intensified human activity in Antarctica are promoting the synanthropization process and increasing the likelihood of alien species establishing in the native communities. Cargo items, expedition members’ equipment and food destined for the 32nd Polish Antarctic Expedition to the “Arctowski” station in the 2007/2008 season were inspected to determine their potential as vectors for alien lichen species. Within the cargo, packaging and foodstuffs scanned, a total of 45 lichen specimens (24 species) were identified. Most of them had been accidentally transported with various timbers. Cargo containers and fresh food were also found to harbour for single specimens. The majority of lichens detected are alien to the Antarctic biota and had never been observed in the region. This paper estimates the potential risk of these lichens establishing themselves in remote southern latitudes. The results emphasize the threat of accidental introduction of alien organisms into Antarctica and the need for taking every precaution to prevent the importation of non-native species to this unique environment. [ABSTRACT FROM AUTHOR]

Copyright of Transylvanian Review of Systematical & Ecological Research is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Because of the increasing anthropogenic fire activity, understanding the role of land-use in shaping wildfire regimes has become a major concern. In the last decade, an increasing number of studies have been carried out on the relationship between land-use and wildfire patterns, in order to identify land-use types where fire behaves selectively, showing a marked preference (or avoidance) in terms of fire incidence. By contrast, the temporal aspects of the relationship between landuse types and wildfire occurrence have received far less attention. The aim of this paper is, thus, to analyze the temporal patterns of fire occurrence in Sardinia (Italy) during the period 2000–2006 to identify land-use types where wildfires occur earlier or later than expected from a random null model. The study highlighted a close relationship between the timing of fire occurrence and land-cover that is primarily governed by two complementary processes: climatic factors that act indirectly on the timing of wildfires determining the spatial distribution of land-use types, and human population and human pressure that directly influence fire ignition. From a practical viewpoint, understanding the temporal trends of wildfires within the different land-use classes can be an effective decision-support tool for fire agencies in managing fire risk and for producing provisional models of fire behavior under changing climatic scenarios and evolving landscapes. [ABSTRACT FROM AUTHOR]

Understanding past anthropogenic influences on fluvial systems is an integral part of riverine research. In this paper the spatial history of kauri driving dam placement from the 1870s to the 1930s is studied using oral histories, historic documents and GIS in an attempt to assess the accuracy of historical accounts in reference to dam position in the landscape and assess the relationship of dam position to landscape features and characteristics. GIS results supported historical documentation showing that key factors influencing dam placement were location to kauri, geomorphic impediments to transport, slope and distance to deep water for rafting. [ABSTRACT FROM AUTHOR]

The subjects of the study were two high-mountain lakes, Morskie Oko and Czarny Staw pod Rysami, in the Tatra range of the Carpathian Mountains located within the protected area of the Tatra National Park. This paper presents results of the analytical study of the lake water composition and compares this with relevant data from earlier years. The impact of the following factors was distinguished and discussed: atmospheric deposition (dry and wet), migration of pollutants with runoff water supplying both reservoirs, tourism (hiking, climbing), and the influence of mountain hostels. The resistance and sensitivity of the lakes to human impact is described in terms of water quality changes and characteristics of the catchments and the region. [ABSTRACT FROM AUTHOR]

This paper presents a brief review of archaeological evidence for the impact of the pre-Hispanic population on the environment of the Canary Islands. Prior to human colonisation, the archipelago was an untouched environment with high botanical and faunal biodiversity. The first human settlement can be traced to the early 1st millennium BC; this period of settlement finished at the end of the 15th century AD when the Spanish Crown conquered the archipelago. It has often been assumed that the pre-Hispanic population had little significant impact on the islands' ecosystems. However, abundant evidence for faunal extinctions, deforestation and soil erosion has been recovered from archaeological sites across the islands. This indicates that pre-Hispanic colonisers introduced cultivated plants, opened up the forests to create fields and cut woody vegetation for fuel. They also introduced domestic animals and alien predators resulting in a major depletion of native fauna. [ABSTRACT FROM AUTHOR]

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]

Studies about processes determining biodiversity in Pantanal are urgently needed and the use of invertebrates for this purpose may be an efficient tool. The purpose of this paper is to verify whether ants could be used to predict human impacts on Pantanal, assessing how environmental characteristics of gallery forest influence arboreal ant species richness. Specifically, we tested the hypotheses that: (i) resource availability (estimated by tree density) and (ii) diversity of environmental conditions (estimated by structural heterogeneity) positively influence arboreal ant species richness and composition. Ants were sampled in a gallery forest in the Miranda River. Ant species richness did not respond to tree density, but increased with structural heterogeneity. Species composition was affected both by tree density and structural heterogeneity. The species list produced in the present study showed a high similarity between arboreal ant faunas of Cerrado and Pantanal, which are contiguous biomes. The relationship of ant species richness with heterogeneity, as well as the observed changes of species composition with tree density and heterogeneity may be explained by the presence of a variation of environmental conditions, which create several micro-habitats in the forest. The response of the ant community can reflect human impacts on the forests of the studied region, which are usually modified to create patches for sport fishing and by pathways used in ecotourism. [ABSTRACT FROM AUTHOR]

In the context of a main project that aims to recover modern data on diatom distribution applicable to paleosalinity reconstructions in coastal areas of Southern South America, the composition and distribution of dead diatom assemblages in the littoral zone of the Quequén Salado estuary (Argentina) were studied. Diatom zones were defined along the estuarine gradient by cluster analysis and related to the salinity range and sediment composition by Canonical Correspondence Analysis. Four diatom zones were identified. A mixture of marine, brackish and freshwater diatoms, probably allochthonous, characterized the inlet (zone I). Marine/brackish taxa, represented mainly by Paralia sulcata dominated zone II, characterized by polyhaline conditions and sandy sediments. Zone III was characterized by mesohaline conditions, muddy sediments and the dominance of the estuarine diatom Amphora helenensis. Brackish/freshwater and freshwater diatoms dominated the headwaters (zone IV), where salinity was always below 5‰. The comparison of Quequén Salado diatom assemblages with previous results from the Quequén Grande estuary showed a similar taxonomic composition between both estuaries. However, differences in the salinity ranges of the estuaries (related to differences in the degree of human impact and tidal range) lead to a displacement in their spatial distribution along the longitudinal estuarine axis. This paper contributes to the knowledge of the ecological requirements of South American estuarine diatoms and provides useful data for paleosalinity reconstructions in the region. [ABSTRACT FROM AUTHOR]

Evidence of abrupt changes in ecosystem states, such as sudden eutrophication in lakes, has been increasingly reported in a variety of aquatic and terrestrial systems. Ecosystems may have more than one state with a self-stabilizing mechanism, so that a shift between states does not occur frequently and is not readily reversible. These big changes are termed regime shifts where often one state is preferred over another. Thus, regime shifts are problematic for ecosystem managers, and the need exists for studies that lead to the identification of thresholds of key variables that trigger regime shifts. Regime shifts are currently difficult to predict and in many cases may be caused by the human pursuit of efficiency in land and water productivity in the last few decades. Here I briefly introduce a theoretical approach to predict the shift between a clear-water state and a turbid state in lakes, the best-studied example of regime shifts. This paper also discusses alternative states in other natural systems besides ecosystems to draw more attention to the research currently being performed on regime shifts. [ABSTRACT FROM AUTHOR]

Question: This paper compares published palynological studies from coastal swamps containing the same suite of species. We ask the following questions: (1) does succession follow the same pathways in different swamp systems, or (2) at different times? If not, (3) how variable are the patterns and (4) what are the likely driving factors? Location: Great Barrier Island, Northern New Zealand. Methods: Eighteen pollen profile diagrams were studied from four estuarine wetlands, ranging from mangroves to swamp forest. Recognition of a transition between vegetation stages was by subjective consideration of the relative abundances of pollen of key indicator species at different depths in the sedimentary sequence. Results: A linear sequence of vegetation communities beginning with mangroves and followed by estuarine marsh communities composed of Juncus kraussii, Leptocarpus similis and Baumea juncea was recognised in almost all pollen diagrams. Further transitions, from Baumea to a terrestrial system of Leptospermum shrubland or Cordyline/Dacrycarpus swamp forest, followed two main pathways associated with autogenic accumulation of peat and terrigenous sediment input respectively. At Kaitoke and Awana the marine/freshwater transition occurred before the arrival of humans on Great Barrier Island. At Whangapoua, increased sedimentation followed anthropogenic burning of adjacent forest, and this transition was faster and is still in progress. Conclusion: Palynology and current vegetation zonation patterns concur to demonstrate that the marine sedimentation phase of estuarine succession is predictable and linear. Baumea marks the transition to the freshwater phase, in which varied successional patterns are determined by interactions between hydrology, sediment input, and peat accumulation. Natural and human disturbances drive sedimentation rates, and interact with autogenic factors, to dictate vegetation transitions in these later stages. The intensive impact (mainly burning) during Polynesian times had a much greater effect on estuaries and swamps than the pre Polynesian natural processes, greatly accelerating plant succession. [ABSTRACT FROM AUTHOR]