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Scientific knowledge advances by the discussions on hypotheses, methods, and results, wherein the contradictory plays a positive role developing new theoretical-methodological approaches. In a positive debate to the progress of the science, the agreements and disagreements must only permeate the scientific scope and based on ethics to be away from the conflicts of interest. From this perspective, after knowing the submission titled Comments on Souza et al. (2022) "Recent geomorphological changes in the Paraiba do Sul delta, South America East Coast" to the journal Progress in Physical Geography: Earth and Environment (PPG), which addressed several issues concerning the results published in that article, we wrote this response to clarify the doubts related to the original paper. The comment's authors focus mainly on da Rocha et al. (2019), a locally published article that did not fully encompass the complexity of processes and geomorphological dynamics related to the delta evolution. Furthermore, it did not present the parameters used in the geochronological analyses in accordance with the international literature. Finally, the discussions presented in the original article contribute to advances in knowledge about the responses of the Paraíba do Sul delta to the Little Ice Age. [ABSTRACT FROM AUTHOR]

The lower Usumacinta–Grijalva River Basin contains one of the richest biodiversity landscapes of the Maya region. Our research is based on (1) an integrative literature review of the geomorphological and archaeological papers published about the lower Usumacinta–Grijalva River Basin and (2) topographic analysis of digital elevation models using a geographical information system to explore the relationship between past human settlement and landscape accessibility along the coastal plain of Tabasco. This work provides a new synthesis of previous research and proposes new models for the geomorphic evolution of the lower Usumacinta–Grijalva River Basin in the context of four millennia of human land use and settlement. For the evolution of the strand-plain of the Usumacinta and Grijalva rivers, there are two published geochronological models that provide different chronologies. We discuss here how both geochronological models encompass Pre-Columbian human settlement in the delta. Interestingly, we notice that one of them overlaps a possible high-magnitude flood event (or events) that drove large geomorphic change around 750 CE (1200 BP), with implications for settlement patterns and chronology. Based on topographical analysis of the eastern-distal sector of the Usumacinta–Grijalva delta, we propose a new model for the evolution of this area with implications for the human occupation during the Mesoamerican Terminal Classic and Early Postclassic on the delta. As one of the main conclusions, we propose that the Pom–Atasta water bodies predate much of the Usumacinta–Grijalva delta and the most recent phase of delta building overlays the original lagoon barriers, resulting in a geomorphic setting more attractive to local human occupation after the Terminal Classic period. According to one of the geochronological models of the delta, this dates to ca. 900 CE, preceding the establishment of nearby settlements such as Atasta. [ABSTRACT FROM AUTHOR]

The climate variability and related sea-level changes during the Holocene are still under discussion, especially in a regional context. Very little information comes from the southern and south-eastern Baltic coast. The aim of the paper is to gain insight on the history of regional environmental changes, particularly sea-level and storminess, and their driving forces. The investigations were located on a peatland on the coast of Puck Lagoon (Gulf of Gdańsk, southern Baltic Sea). The analysis of peat core comprised: radiocarbon dating, analysis of stable isotopes 18O and 13C and chemical components, as well as palynological and diatomic studies. Results showed the 1.0 m peat section accumulated over 1500 years, with a time resolution of 100 years per sample. The average water level in the Puck Lagoon rose by ca. 0.85 m during the last 1500 years in a cyclic mode, with a period cycle of ca. 600–550 years and an amplitude not exceeding 0.5 m. The accelerated sea level rise and frequent storminess occurred during the first half of the Dark Ages (1500−1300 years b2k) and LIA (750−450 years b2k) and since the beginning of the 20th century. Recognized environmental changes are well correlated with both temperature changes in the North Atlantic and changes in total solar irradiance, suggesting synchronous Northern Hemisphere-wide fluctuations. The solar forcing was an important constituent of natural climate variability in the past and of forcing climate warming during modern times - after the Little Ice Age. [ABSTRACT FROM AUTHOR]

This paper presents continuous, high resolution fossil pollen and microcharcoal records from Bo Langvlei, a lake in the Wilderness Embayment on South Africa's southern Cape coast. Spanning the past ~1300 years and encompassing the Medieval Climate Anomaly (MCA; c. AD 950–1250) and the Little Ice Age (LIA; c. AD 1300–1850), these records provide a rare southern African perspective on past temperature, moisture and vegetation change during these much debated periods of the recent geological past. Considered together with other records from the Wilderness Embayment, we conclude that conditions in the region during the MCA chronozone were – in the context of the last 1300 years – likely relatively dry (reduced levels of Afrotemperate forest pollen) and perhaps slightly cooler (increased percentages of Stoebe -type pollen) than present. The most significant phase of forest expansion, and more humid conditions, occurred during the transition between the MCA and the most prominent cooling phase of the LIA. The LIA is clearly identified at this locality as a period of cool, dry conditions between c. AD 1600 and 1850. The mechanisms driving the changes observed in the Bo Langvlei pollen record appear to be generally linked to changes in temperature, and changes in the influence of tropical circulation systems. During warmer periods, moisture availability was higher at Bo Langvlei, and rainfall was perhaps less seasonal. During colder periods, precipitation resulting from tropical disturbances was more restricted, resulting in drier conditions. While increased precipitation has been reported during the LIA from Verlorenvlei in the Western Cape as a result of an equatorward displacement of the westerly storm-track at this time, the opposing response at Bo Langvlei suggests that any increased influence of westerlies was insufficient to compensate for the concurrent reduction in tropical/local rainfall in the region. [ABSTRACT FROM AUTHOR]

Multidisciplinary studies in coastal systems of the eastern Mediterranean region have proven to be excellent tools in understanding paleoenvironmental, paleoecological, and paleoclimatic changes that took place during the Holocene period, and how these changes interacted with urban development and growth. This paper presents sedimentological, high-resolution x-ray fluorescence (XRF scanning), micropaleontological, and x-ray diffraction (XRD) data from three shallow sediment cores that were retrieved from Aliki (ancient Siphai or Tipha) salt pond. The study area is located in a unique, highly tectonic geographical region, at the northeast part of the Gulf of Corinth in Greece. Beachrock deposits that form a barrier between the salt pond and the marine environment seem to play an important role in the evolution of the area. The chronological framework was set at around 3100 cal. BP by four 14C radiocarbon dates, and the evolutionary model that was established indicates four different changes taking place during this period at the study area. From around 3100 to 1600 cal. BP, a transition from a closed to an open lagoonal environment was identified, interrupted by a fluvial terrestrial deposit at around 2500 cal. BP. A shift toward a closed lagoonal system at around 1600 cal. BP and the establishment of a salt pond environment seem to correlate with tectonic activity. The study provides important information about the evolution of coastal landscape in such a tectonic active region and points the interaction between regional human activity and climatic changes during the late-Holocene period. [ABSTRACT FROM AUTHOR]

This paper presents the first pedoanthracological study carried out on two mountains of the Northern Apennines, Monte Cimone, and Corno alle Scale, where the results provided new palaeoenvironmental data. The pedoantracological sampling followed an elevation gradient from the current timberline to the highest possible elevation, also adapted to the geomorphological characteristics of the study areas. Based on radiocarbon datings (16 at Monte Cimone and 9 at Corno alle Scale), the soil charcoal fragments provided data about the vegetation dynamics and plant landscape reconstruction, primarily indicating the Late Holocene. The landscape over the last 3000 years appears very similar to the current one with very small altitudinal variations of the timberline and treeline. The present study shows a lack of radiocarbon dates for the Middle Holocene and two hypotheses are discussed to explain this finding. Data suggest that past fires were locally linked to periods of climate optimum and possibly with the management of natural resources (especially animal grazing) by human societies. Some questions concerning the absence of Abies alba, today only present as plantation and normally associated with Fagus sylvatica at these latitudes, are discussed. [ABSTRACT FROM AUTHOR]

Occupying 4% of Crimea's territory, the sub-Mediterranean landscapes of Southern Crimea stand out for their distinct soil-climatic conditions and record of human activity. This paper presents the results of study of the newly formed and well-dated soils from 21 archaeological sites, making it possible to build a soil chronosequence covering the last 2.3 ka. To study the natural processes on an intra-secular scale, short series of instrumental meteorological observations were extended, based on dendrochronological records, to a total of 160 years, and the time series of solar activity and energy for pedogenesis were correlated. These data are collated with a 4.2-ka Lake Saki varve record, which was re-analysed applying the DFT spectrum analysis method, with three distinct phases in relative secular variations in precipitation being identified. The phase of a relative climatic stability with moderate variations in precipitation (3.2-1.25 ka BP) was followed by the period of increased moisture (from 1.25 ka BP), unparalleled since the Late Bronze Age. Given the decisive role of increased moisture in the climate-controlled energy expenditures for pedogenesis, in the dynamics of vegetation cover and human ways of life, the identification of these periods contributes to a better understanding of soil-climate relationship and cause-and-effect for nonlinear change in the settlement and landscape history of the region. [ABSTRACT FROM AUTHOR]

In this paper, we present the results of the geoarchaeological studies carried out in two archaeological localities of the Upper Delta of the Paraná River (Argentina). The main objective of these studies is to depict the pre-Hispanic strategies involved in the colonization and settlement of southern South America wetlands. Paraná Delta is one of the most conspicuous areas of these lowlands and comprises a large wetland macrosystem. Its current geomorphological configuration was established after the last transgressive mid-Holocene event c. 6000 14C yr BP. In this environment, a high ecological heterogeneity, with diverse and abundant tropical and temperate biota, was developed. These features were important factors to the human colonization and utilization of these wetlands. However, this environment has the highest hydrometeorological susceptibility of La Plata basin. This susceptibility had an impact on settlement systems and resource exploitation strategies established in the area since at least 2000 14C yr BP. These strategies involved at least two settlement types: semi-permanent residential camps and transitory camps oriented to exploit particular resources. The semi-permanent settlements were located in anthropogenic elevated mounds, locally known as 'cerritos', and were not subjected to seasonal inundations. Conversely, the transitory camps are found in levees exposed to recurrent flooding. [ABSTRACT FROM AUTHOR]

The Peruvian coastal upwelling is one of the most productive systems in the global ocean, with important impacts on the carbon cycle. Primary productivity there displays strong variations at the interannual to decadal timescales. However, down-core investigations rarely reach sufficient temporal resolution to assess the response of productivity to climatic variations at these timescales beyond the instrumental and historical periods. We here analyzed diatom assemblages, sea-surface temperatures (SSTs), and nitrogen and organic carbon contents on a laminated sediment core from the Peruvian continental shelf to trace variations in regional productivity over the last 3000 years. Our record provides evidence for different climatic and oceanic conditions with more humid and less productive conditions older than 2500 cal. yr BP and drier and more productive conditions younger than 2500 cal. yr BP. The last 2500 years also present much stronger centennial-scale variability with the occurrence of six intervals with higher total diatom abundances and stronger percentages in upwelling-related diatom species, representative of intensified productivity, congruent to lower percentages in benthic diatoms, indicative of reduced rainfall. These six periods were synchronous to intervals of enhanced Walker circulation, suggesting a strong imprint of the Pacific zonal circulation on productivity variations off Peru. Our record also demonstrates that SSTs did not vary in phase with productivity, arguing against the idea of regional SSTs controlled by the upwelling intensity, but were rather in agreement to SST records off southern Chile, suggesting that Peruvian SST variations were largely controlled by oceanic currents at southern high latitudes. [ABSTRACT FROM AUTHOR]

Archaeologists make inferences about past human behaviour based on patterned material residues in various depositional contexts, including existing landsurfaces. These deposits are generated by processes that may obscure patterns at some observational scales while highlighting others, and interpretive differences can arise from a lack of explicit models of deposit formation. Here, an exploratory agent-based model based on the concept of the palimpsest is used to examine the effects of episodic sediment transport on the visibility and preservation of surface archaeological deposits in a fluvial context. Outcomes from the model indicate that the compound influences of preservation and visibility are capable of transforming a static radiocarbon record into one of increasing intensity towards the present, while simultaneously displaying periodic chronological gaps – features that have been used in our Australian study area to argue for demographic change driven by social or environmental factors. To differentiate between interpretations, expectations derived from the model are assessed against a second proxy from the same study area: Optically Stimulated Luminescence dates from hearth stones in surface contexts. Results indicate that patterns in the chronometric proxies from the study area are more consistent with episodic geomorphic change than explanations invoking changes in the local organization of human activity. [ABSTRACT FROM AUTHOR]

Micro x-ray fluorescence (µXRF) core scanning is capable of measuring the elemental composition of lake sediment at sub-millimetre resolution, but bioturbation and physical mixing may degrade environmental signals at such fine scales. The aim of this research is to determine the maximum possible resolution at which meaningful environmental signals may be reconstructed from lake sediments using this method. Sediment from a coastal lake in the Outer Hebrides, Scotland, has been analysed using calibrated element measurements to reconstruct storminess since AD 200. We find that a Ca/K ratio in lake-core sediments reflects the presence of fine calcium carbonate shell fragments, a constituent of sand in the catchment that is washed and blown into the lake. Variations in this ratio are significantly correlated with instrumental records of precipitation and low pressures, suggesting it is a proxy for storminess. Furthermore, identification of a c. 60-year cycle supports a climatic influence on Ca/K, as this cycle is frequently identified in reconstructions of the North Atlantic Oscillation and North Atlantic sea-surface temperature. Comparison with weather records at different resolutions and spectral analysis indicate that µXRF data from Loch Hosta can be interpreted at sub-decadal resolutions (equivalent to core depth intervals of 3–5 mm in this location). Therefore, we suggest that sub-centimetre sampling using µXRF core scanning could be beneficial in producing environmental reconstructions in many lake settings where sediments are not varved. [ABSTRACT FROM AUTHOR]

Carroll College and the Helena National Forest are working in a 6-year research partnership designed to investigate the relationship between paleoclimate change and human adaptation in the Big Belt Mountains of central Montana, USA. This ongoing project is designed to gather archaeological and paleoenvironmental data from three diverse ecosystems within one drainage basin: high-altitude park areas (1800–2100 m), mid-altitude conifer forests (1200–1500 m), and low-altitude locales (under 1500 m) along the Missouri River. These data will represent paleoecological and archaeological changes through time and will detect synchrony and diversity across an elevation gradient. Thus far, excavation of two mid-altitude sites, dating to 2400 and 4500 BP, and one high-altitude site, dated to 2400 BP, revealed evidence of a significant drought period about 2000 years ago. To date, the excavated sites evidence a shift in pollen to drier species, a shift to higher sedimentation rates, and changes in snail and vertebrate species. [ABSTRACT FROM AUTHOR]

The Indian monsoon system is an important climate feature of the northern Indian Ocean. Small variations of the wind and precipitation patterns have fundamental influence on the societal, agricultural, and economic development of India and its neighboring countries. To understand current trends, sensitivity to forcing, or natural variation, records beyond the instrumental period are needed. However, high-resolution archives of past winter monsoon variability are scarce. One potential archive of such records are marine sediments deposited on the continental slope in the NE Arabian Sea, an area where present-day conditions are dominated by the winter monsoon. In this region, winter monsoon conditions lead to distinctive changes in surface water properties, affecting marine plankton communities that are deposited in the sediment. Using planktic foraminifera as a sensitive and well-preserved plankton group, we first characterize the response of their species distribution on environmental gradients from a dataset of surface sediment samples in the tropical and sub-tropical Indian Ocean. Transfer functions for quantitative paleoenvironmental reconstructions were applied to a decadal-scale record of assemblage counts from the Pakistan Margin spanning the last 2000 years. The reconstructed temperature record reveals an intensification of winter monsoon intensity near the year 100 CE. Prior to this transition, winter temperatures were >1.5°C warmer than today. Conditions similar to the present seem to have established after 450 CE, interrupted by a singular event near 950 CE with warmer temperatures and accordingly weak winter monsoon. Frequency analysis revealed significant 75-, 40-, and 37-year cycles, which are known from decadal- to centennial-scale resolution records of Indian summer monsoon variability and interpreted as solar irradiance forcing. Our first independent record of Indian winter monsoon activity confirms that winter and summer monsoons were modulated on the same frequency bands and thus indicates that both monsoon systems are likely controlled by the same driving force. [ABSTRACT FROM AUTHOR]

Using a combination of 23 radiocarbon ages and annual ring counts from 18 Rocky Mountain bristlecone pine (Pinus aristata) remnants above the local present-day limits, a period of higher treeline has been determined for two sites near the Continental Divide in central Colorado. The highest remnants were found about 30 m above live bristlecone pines of similar size. The majority of the remnants, consisting of standing snags, large logs, and smaller remains, are highly eroded, such that the innermost annual rings of all but one are missing. The radiocarbon ages obtained from the oldest wood recovered from each remnant indicate that the majority were established above the present-day limit of bristlecone pine from prior to 2700 cal. yr BP to no later than about 1200 cal. yr BP. These radiocarbon ages combined with the annual ring count from the corresponding remnant indicate that the majority of the sampled remnants grew above the present-day limit of bristlecone pine from sometime before 2700 cal. yr BP to about 800 cal. yr BP. Evidence of recent climatic warming is demonstrated at one of the sites by young bristlecone pine saplings growing next to the highest remnants; the saplings were established after AD 1965 and represent the highest advance of treeline in at least 1200 years. [ABSTRACT FROM AUTHOR]

Lacustrine ecosystem history since the industrial revolution provides important evidence of natural versus anthropogenic effects on the environment. With high-resolution sedimentary core samples and organic–inorganic geochemical methods, we reconstruct the past ~150-year ecosystem evolution of Lake Wuliangsu in the upper reaches of the Yellow River, and probe factors controlling the ecological dynamics. In this study, ecological changes in Lake Wuliangsu over the past ~150 years were identified. After the lake formed in the 1850s, biological productivity of the lake was still under-developed until the 1950s. During the period of 1950s–1970s, submerged macrophytes became the dominant organisms in the lake because of lake area expansion and slight increases of nutrient input from agricultural development in the catchment. The domination of submerged macrophytes ceased after the 1970s, which was possibly induced by the shrinkage of the lake area. After the 1990s, the main contributor of sedimentary n-alkanes most likely shifted to reeds because of eutrophication caused by anthropogenic activities. The results clearly demonstrate that the ecosystem in Lake Wuliangsu before the 1950s strongly depended on the natural discharge, whereas at later stages, it was significantly influenced by human activities. During the period of 1950s–1990s, the human-monitored lake area seems to be the main factor in the lake ecosystem evolution. However, when the nutrient supply went beyond the tipping point after the 1990s, eutrophication took over and played a key role in the lake ecosystem evolution. [ABSTRACT FROM AUTHOR]

Stable isotopes in mollusk shells have been widely used for hydrological balance reconstructions. However, their use is restricted to lakes that preserve the calcareous material of the shells. Lago Cisnes is located in Patagonia (47°S) and shows a continuous record of three species of mollusk during the past 5000 years. The isotopic records of δ18O in Pisidium sp., Lymnaea sp., and Biomphalaria sp. show discrepancies among them, which can be explained by the differential effect that evaporation has on the habitat where each species lives. Between 1800 and 500 cal. yr BP, the three species show similar isotopic variations, suggesting that climatic condition affecting in the same way the different microhabitats in the lake. Around 1700 cal. yr BP, an enrichment of 18O on mollusks shells indicates drier conditions that prevails until 1100 cal. yr BP. Later on, isotopic signal tends to decrease, suggesting a humid period between 750 and 500 cal. yr BP. Such humid conditions lasted until 170 cal. yr BP, which were evidenced only by Biomphalaria sp. and Pisidium sp. Climate variability during the late Holocene in Lago Cisnes is in agreement with marine records from northern Patagonia, which would suggest westerlies weakening during a northward migration after 1100 cal. yr BP and/or an important temperature control on the evaporation, where low temperatures could decrease the evaporation driven by the westerlies. Additional records in this area would be requested to clarify the westerlies effects on the east flank of the Andes. [ABSTRACT FROM AUTHOR]

In this study, we investigated morphologically and geochemically a skull from an open pit situated on the Călineasa-Şesu Gârzii Plateau, Bihor Mountains. The study presents the first 14C dating and stable isotope composition of bison skeletal remains from the Romanian Carpathians. The result of 14C determination yielded two relevant maxima: one is around AD 1550 and the second around AD 1645. The data indicate that the investigated bison died during the ‘Little Ice Age’ (LIA), approximately 200 years before the last ones were hunted to extinction. Stable isotope composition of carbon from bison tooth enamel suggests that the bison diet consisted mainly of C3 grasses, compatible with a high-altitude habitat, vegetation distribution and low mobility. Oxygen isotope composition of both phosphate and carbonate groups of tooth enamel indicates that the bison drank from stagnant water sources, such as lakes or puddles formed from rain water. This further suggests low mobility of the bison as well, as the presence of such small stagnant water sources is characteristic even today for the plateau. Calculated oxygen isotope compositions of rain and drinking water at the time the bison lived indicate a lower relative humidity, around 60–70% at that period of LIA when the bison lived, which is lower than today’s humidity of 80%. [ABSTRACT FROM AUTHOR]

Anthracological analysis has been carried out in the Medieval site of Miranduolo, a rural settlement in southern Tuscany with a sequence of occupation between the 7th and 14th century AD. Between the 7th and mid-9th century AD, during the phase of a Lombard farming village, the strong presence of Castanea sativa as timber for building showed that chestnut was the preferred species for carpentry and fuelwood, suggesting coppice management of chestnut woods for timber production. The Miranduolo data, set against the archaeobotanical data in the literature, rejected the hypothesis of chestnut cultivation as a fruit tree and corroborated the hypothesis that the plant was initially used for timber production during the Early Middle Ages, continuing the woodworking tradition of the Roman period. From the mid-9th century AD, during the Carolingian feudal system, chestnut in the feudal estate of Miranduolo ceased to be used for building and firewood, while deciduous Quercus was preferred. At the same time, chestnut fruits began to be picked and kept in warehouses at the disposal of the feudal lord, suggesting the management of chestnut woods for fruit production. Comparison with existing archaeobotanical data revealed that chestnut cultivation for fruits began in this period in other Italian regions also, encouraged by different economic systems. From the 10th century, in Miranduolo chestnut was exploited both for timber and fruit suggesting the abundance of this resource in high managed stands. Comparison with coeval archaeological sources, archaeobotanical data and pollen records suggested from this period the strong expansion of this species that gradually took place throughout central and southern Italy, becoming a ‘multifunctional’ high-forest. The current chestnut forest landscape in central Italy is thus of human origin, expanding and changing over about 1000 years of cultivation. [ABSTRACT FROM AUTHOR]

It is currently suggested that climate change on the northeastern Tibetan Plateau (TP) was influenced alternately by the monsoon and the Westerlies. However, the mechanisms driving Holocene climate change on the TP remain unclear, since the extent of the influence of individual atmospheric circulation systems has not yet been clearly defined because of the shortage of high-quality paleoclimatic records. This is especially true in the central TP, where only a few ice core and paleolimnological records are available. Here, we present a decadal-resolution temperature record from Dagze Co in the central TP for the past 2000 years, based on the unsaturation index of long-chain alkenones, using an updated temperature calibration, and a record of precipitation isotopes from compound-specific isotope ratios of leaf waxes. The centennial-scale variation of the temperature and precipitation isotope records captures well-known climatic events over the past 1000 years, for example, the ‘Little Ice Age’, which was cooler and drier than the ‘Medieval Warm Period’. However, the relationship between temperature and the precipitation isotope records differed during the interval at 2000–1000 cal. yr BP compared to the past 1000 years, probably because of changes in precipitation seasonality and the additional influence of the Westerlies on the central TP. In addition, the temperature records exhibit a prominent 210-year cyclicity, suggesting a possible influence of solar radiation on temperature variability. [ABSTRACT FROM AUTHOR]

Central Chile is heavily exploited for mineral and water resources, with agriculture and large urban populations all creating intensive landscape use. Few records of past environmental and climate change are available that afford a broader context. To aid in this assessment, we present a 700-year reconstruction from Laguna del Maule (LdM) in the high Andes of central Chile based on sedimentological, geochemical, diatom and pollen analyses. The age model is based on 210Pb/137Cs and 14C dating tied into known volcanic eruptions. Sedimentology consists of organic-rich sediments and diatom oozes with several interspersed volcanic-rich facies and two tephra deposits. Sediment geochemistry exhibits increased productivity (high Br/Ti, biosilica) and more dominant oxic conditions (high Fe/Mn) from AD 1300 to 1400 and from AD 1650 to 1850, likely during periods of relatively lower lake levels and better development of littoral environments. However, during this later period, high elevation vegetation was dominant, indicative of regional cooler/wetter conditions. In contrast, sediments deposited from AD 1850 to 1930 evidence decreased productivity and increased anoxic lake bottom conditions. The ‘Little Ice Age’ (LIA) in LdM is characterized by significant variations in lake dynamics and hydrology with cooler/wetter conditions (AD 1570–1700), major environmental changes in the 18th century and ending at ca. AD 1850. LdM record documents the impact of the LIA in the southern hemisphere and stresses the global nature of this climate period. Large changes in lake dynamics and diatoms assemblages during the 20th century could be related to anthropogenic impacts, but recent changes in climate patterns cannot be excluded. [ABSTRACT FROM AUTHOR]

The inexpensive Blue Intensity proxy has been considered a complement or surrogate to maximum latewood density (MXD), but is associated with biases from differential staining between sapwood and heartwood and also between deadwood samples and living-wood samples that compromise centennial-scale information. Here, we show that, with some minor adjustments, ΔBlue Intensity (ΔBI) is comparable with MXD or ΔDensity (Δ = the difference or contrast between latewood and earlywood density) in dendroclimatological reconstructions of summer temperatures in the Central Scandinavian region, using Pinus sylvestris L. (Scots pine), on annual and multi-centennial timescales. By using ΔBI, this bias is significantly reduced, but the contrast between earlywood and latewood in BI is altered with degree of staining, while for density it is not. Darker deadwood samples have a reduced contrast compared with the lighter living-wood samples that make ΔBI and ΔDensity chronologies diverge. Here, we quantify this behaviour in BI and offer an adjustment that can reduce this bias. The adjustment can be derived on independent samples, so in future work on BI, parallel density measurements are not necessary. We apply this methodology to two Central Scandinavian Scots pine chronologies that averaged into a composite is able to reconstruct summer temperatures with an explained variance in excess of 60% in each verification period using a split sample calibration verification procedure. Although the amount of data used to derive this contrast adjustment produces desirable results, more tests are needed to confirm its performance, and we suggest that future work on the BI proxy should aim for a small subset of parallel BI and density measurements while the bulk of the data is only measured with the BI technique. This is to ensure that the adjustment is continuously updated with new data and that the conclusions derived here are robust. [ABSTRACT FROM PUBLISHER]

Climate change and human activities interact to affect the vegetation landscape. We examined the interaction of these drivers using multiproxy records, including data on pollen, charcoal, phytoliths, total nitrogen, total organic carbon, and loss-on-ignition, from a 268-cm sediment profile in Xinjiang, China. By combining these data with information gained from 214 samples of surface pollen assemblages in north Xinjiang, we were able to reconstruct the late Holocene climate using a weighted averaging partial least squares regression model. Our results suggested that the typical desert vegetation of the region changed to Artemisia desert at 2400 cal. a BP, and returned to desert after 900 cal. a BP. A warm–dry and cold–humid climate pattern existed during the past 4000 years. The climate was characterized by obvious fluctuation prior to 2400 cal. a BP, after which it became wetter and colder with little fluctuation. The temperature maximum in our reconstruction occurred around 700 cal. a BP. The macrocharcoal particles reached their highest levels at c. 3500 cal. a BP, and again at 700 cal. a BP, suggesting increases in human activities at these times. An increased amount of anthropogenic plant pollen also appeared in sediment over the past 50 years. Large numbers of Thelypteris spores and Phragmites phytoliths in the surface pollen samples from modern desert vegetation also reflect recent human activities. Therefore, our data provide evidence that both climate and human activities are important drivers of changes in regional vegetation. [ABSTRACT FROM PUBLISHER]

The core MD03-2693 (43°39.258′N; 01°39.805′W; 431 m water depth) was collected on an abandoned meander of the Capbreton Canyon (SE Bay of Biscay), filled over the last millennia by very high sedimentation rates (mean sedimentation rate of 1.2 cm/yr) linked to its specific environmental location and fine-grained clayed sediment decantation from the proximal canyon axis. This archive thus permits to undertake the study of late Holocene regional climatic patterns at a decadal temporal resolution. In the present work, we use data derived from planktonic foraminifera assemblages coupled to a multiproxy approach that associates grain-size measurements, x-ray fluorescence (XRF) elemental analysis and stable oxygen isotope on Globigerina bulloides shells to infer Sea Surface Temperature (SST) and Sea Surface Salinity (SSS) changes over the last two millennia. Signals reconstructed in the Bay of Biscay show significant oscillations that are consistent with well-known temperature anomalies such as the ‘Little Ice Age’ (LIA) and the ‘Medieval Warm Period’ (MWP). It additionally displays strong similarities with other areas in the western temperate and northern North Atlantic Ocean, suggesting a narrow coupling between its main gyre surface systems. Abrupt decrease of SSS together with significant change in terrigenous inputs suggests a change in precipitation regime at the onset of the LIA (around ad 1400). Moreover, superimposed to the relative long-term change in environmental parameter, the core MD03-2693 records rapid and discrete pulses of sand grain–sized material that are correlated with the local history of migration of the mouth of the Adour River. [ABSTRACT FROM PUBLISHER]

Chronological precision is a pre-requisite for all palaeoecological analyses, especially in more recent Holocene deposits such as small hollow peat and mor humus in woodlands. Here, tephrochronology was employed to improve the chronological control of such deposits to aid subsequent sub-fossil insect analyses from three sites in western and southwestern Ireland. Six tephra layers were detected from the three small hollows but only one from the mor humus sites. Four of the layers were matched to known tephra horizons regularly recorded in Ireland while two new tephras of possible Azores and Grímsvötn origin were recorded. The latter tephra may be the first definitive record of Laki 1783-4 from Ireland and is potentially an important new chronological marker for Irish palaeoecological investigations of late Holocene deposits. Results suggest that tephrochronology is a successful additional chronological tool for small hollow palaeoecological studies but is less helpful in mor humus deposits. [ABSTRACT FROM PUBLISHER]

Long forest continuity has often been linked with high conservation value in western European Quercus and Fagus woodlands, but this assumption of long continuity has rarely been tested. Birks discussed the antiquity of bryophyte-rich Quercus woodland in western United Kingdom, presenting evidence that the modern plant communities developed during the late Holocene influenced by human activities. We use pollen data from forest hollows to show that the modern communities within ancient woodlands are all significantly influenced by recent human disturbance. A short period of deforestation in Johnny’s Wood, Cumbria, UK dates from the late 19th century and is not of Viking age as previously thought. The brief opening of the forest is associated with the local loss of Tilia cordata and Taxus baccata, but a rich bryophyte community exists today. Rich lichen floras of high conservation interest growing on Fagus sylvatica in south-western Sweden occur despite a recent history of human disturbance and local immigration of Fagus as recently as the 9th century ad. Wistman’s Wood, Cornwall, UK had a diverse tree flora until the 11th century ad and then experienced heavy browsing and grazing until ad 1850, after which time the present Quercus woodland developed with its associated flora of high conservation value. Most western European forests today have long and diverse histories of anthropogenic disturbance and current conservation values incorporate both natural and cultural features. Pollen studies with high spatial resolution demonstrate that simple temporal concepts like ‘natural baselines’ and the continuity of forest cover underestimate the complexity of the past. Long forest continuity may be of importance for the local survival of higher plants, but for the insects, fungi, lichens and bryophytes that are so valued in contemporary European temperate and boreal forests, habitat diversity maintained by dynamic processes would appear to be of greater significance. [ABSTRACT FROM AUTHOR]

The identification of wetter and drier phases from the last deglaciation to the Late Holocene has been a valuable outcome of palaeoenvironmental (chiefly palynological) studies of northeastern Australia conducted over the past 40 years. Few studies have, however, focussed on the identification of wetter and drier phases in the wet tropics, and none have set their focus on the last 4000 years, a period when northeastern Australia is generally accepted to have experienced increased El Niño/Southern Oscillation (ENSO) activity. The present study provides this palaeoclimatic information using the degree of peat humification as the main palaeoclimatic proxy. To identify regional climatic signals in the peat record and differentiate these from local signals induced by particular basin hydrology or ecology, sedimentary sequences from two geographically separated swamps on the Atherton Tableland in north Queensland are examined. Wet and dry shifts are detected in the humification records for Bromfield Swamp (core BSAT03) and Mount Quincan crater swamp (Q2). Seventeen wet shifts are detected in both records with 12 shifts showing good cross-correlation at the following dates (with 2σ range): 3990/3960 (4090–3850), 3480/3550 (3640–3420), 2950/2990 (3080–2790), 2860/2880 (2980–2700), 2560/2610 (2730–2450), 1880/1820 (2100–1740), 1430/1410 (1660–1320), 1170/1080 (1390–1020), 990/1010 (1100–790), 610/640 (710–490), 290/300 (330–180) and 120/150 (190–40) cal. yr BP. A particular dry phase, initiated by dry shifts at 4090 cal. yr BP (Bromfield Swamp) and 4330 cal. yr BP (Mount Quincan), reaches its greatest strength at 4050 cal. yr BP. [ABSTRACT FROM AUTHOR]

Glaciar Perito Moreno (hereafter GPM; 50°30′S and 72°50′W) is a major outlet glacier from the South Patagonia Icefield. In contrast to most Patagonian glaciers, glaciological studies indicate that GPM has been advancing or remained stable during the 20th century. The advances periodically block Canal de los Témpanos creating an ice dam that impounds Brazo Sur–Rico arms of Lago Argentino, raising their elevations, until the water is released in a major outburst flood. Documentary evidence indicates that GPM reached the coast of Península de Magallanes for the first time in 1917. However, the first major damming and rupture event occurred in 1936, when the flooding of the shorelines of Brazo Sur–Rico killed thousands of Nothofagus trees, some still standing dead today. Naturalists who visited the area before 1936 described dense forests extending downslope to the shoreline, confirming the evidence of photographs from 1899 to 1928 displaying no standing dead trees by the shores. Estimates of the water level in Brazo Sur–Rico during each glacier damming vary but indicate values of 10–12 m for the 1936–1948 events and maxima of 23.5 m for the 1954–1956 ice dams. There is evidence for 21 ice dams between 1936 and 2013 with an average interval of c. four years from 1936 to 1988 and c. two years between 2004 and 2012. However, ring counts from standing Nothofagus dead trees along the flooded shorelines indicate that the oldest trees killed by drowning were at least 250 years old providing evidence of no major damming and rupture events from c. 1650 to 1936. These data indicate that damming and outburst events by GPM, world-renowned processes, did not occur for a long-term period before 1936. Unlike most glaciers in Patagonia, GPM was less extensive in the 1700s and 1800s than it is today. [ABSTRACT FROM AUTHOR]

New geomorphological investigations along the coasts of Corfu, Othonoi, Paxoi, and Antipaxoi Islands allowed the identification of recent fossil shorelines. Former sea-level positions were deduced from sea-level indicators. A ‘modern’ tidal notch, submerged c. −20 cm, was observed in all studied islands. This notch is regarded to have been submerged by the global sea-level rise that occurred during the 19th and 20th centuries at a rate exceeding the possibilities of intertidal bioerosion. Its presence provides evidence that no vertical tectonic movements occurred since its formation. On Corfu, impacts of ancient earthquakes have left some marks of emergence at about ≥+130 ± 11, +110 ± 11, +65 ± 11, +40 ± 11, and +25 ± 11 cm, as well as marks of submergence at about −40 to −50, −85 ± 11, −120 ± 11, and −180 ± 11 cm. The emergence of +130 ± 11 cm, previously dated at about 790–400 cal. bc, was detected through erosion notches at various sites in the western part of Corfu and appears to continue even more west, at Othonoi Island. Tidal notches submerged at depths exceeding 0.4 m were observed in the northeastern part of the island and suggest the local occurrence of a sequence of four coseismic subsidences, with average vertical displacements of 40 cm, during at least the last few millennia. At Paxoi and Antipaxoi, Holocene vertical movements seem to have been mainly of subsidence. At Paxoi, the ‘modern’ notch was found at about −20 to −30 cm, while four more submerged tidal notches were distinguished at about −40 ± 11, −60 ± 11, −75 ± 11, and −90 ± 11 cm, while in Antipaxoi, three submerged tidal notches were distinguished at about −60 ± 11, −75 ± 11, and −120 ± 11 cm. [ABSTRACT FROM PUBLISHER]

Anthracological analysis has been carried out in three sites located on the Tyrrhenian coast of central Italy (ancient northern Etruria: the castle of Donoratico, the town of Populonia and the port of Alberese), spanning between the Roman Republican Period and the Late Middle Ages (3rd century bc–13th century ad). The integrated comparison of three different local charcoal data with the regional pollen and microcharcoal data available from northern Etruria showed well that vegetation changes are completely independent of climate and strictly connected to economic and social dynamics characterising the history of this part of central Italy. Indeed, Quercus ilex forests progressively retracted from the 3rd century bc in favour of open macchia formations just during the growing human impact of the Romanisation when intensive agriculture and livestock grazing characterised the economic system. The transition from macchia to deciduous Quercus forest at the end of the Roman Period from the mid-4th to the mid-5th centuries ad and long lasting until the 9th–10th centuries ad was related to economic and cultural factors which led to a phase of land abandonment. Finally, between the 11th and 13th centuries ad, the vegetation cover shifted again towards an open macchia environment at the same time of a re-settlement phase well evidenced also by intensive orcharding. Charcoal data also showed that the expansion of olive and chestnut in central Italy only began in the Late Medieval Period (11th century ad) and not in the Roman Period. This means that extensive cultivation of chestnut and olive has very recent origins and should be attributed to one and the same macro-factor such as the set-up of the economic establishment of the feudal system and the later political organism of the Medieval town. [ABSTRACT FROM PUBLISHER]

A pollen diagram from Lac Brulé in southwestern Québec (45°43′09″N, 75°26′32″W, 270 m) provides a late Holocene history of the vegetation. The presence of varved sediments permitted the development of a high-resolution (10-year), cross-dated chronology with an estimated error of approximately 1%. During the last 1400 years, the forests were dominated by Tsuga, Fagus, Betula, Acer and Pinus. A peak in microcharcoal and evidence of post-fire succession suggest that the changes in the pollen assemblages around ad 1375 were a consequence of a fire in the region. There was a decrease in pollen influx of several deciduous taxa and Tsuga between ad 1600 and 1700, suggesting a rapid climate change that was significant enough to have affected pollen production of these taxa. This change, associated with the beginning of the ‘Little Ice Age’ in the region, affected the forest composition for the subsequent centuries. A detailed comparison of this pollen record with that from a nearby pollen diagram also prepared at high-temporal resolution shows the ability of pollen records to record short-period climate variations and disturbances. [ABSTRACT FROM PUBLISHER]