The Holocene

Anticosti Island, located in the Gulf of St. Lawrence (GSL; Quebec, Canada) is covered by ~25% peatland ecosystems, and conditions supporting their development remain poorly documented. We present the first reconstructions of the ecohydrological conditions (vegetation successions and water table variations) and related carbon accumulation of two maritime peatlands (Pluvier; PLU and Pointe de l’Est; PTE) located on the eastern part of Anticosti Island. These ombrotrophic peatlands developed under the influence of the GSL sea-surface conditions in interaction with atmospheric circulation during the Holocene. Long-term apparent Rate of Carbon Accumulation (LORCA, g C m⁻² a⁻¹) at PLU (13.3) and PTE (16.8) are lower than the mean global value for northern peatlands (22.9), likely due to high wind exposure. Results show that despite the earlier peat inception at PLU (9440 cal a BP) before PTE (6250 cal a BP), the fen-bog transition of both peatlands occurred almost synchronously (4540 and 5070 cal a BP respectively), suggesting favourable hydroclimatic conditions for peat growth. A slowdown in peat accumulation combined with dry and variable hydrological conditions after ca. 3300 cal a BP in the two studied peatlands coincided with the transition from the mid-Holocene to the Neoglacial cooling. At ca. 800 cal a BP, the shift from wet Sphagnum to dry ligneous peat corresponds to the transition from the Medieval Climate Anomaly to the Little Ice Age. Cooling periods, characterized by a decrease in incident solar radiation and the incursion of cold and dry Arctic air masses into the GSL, are marked by a decrease in peat accumulation, especially at PLU, due to its higher wind exposure, which influenced reduced snow cover thickness as well as frost penetration and duration through the peat.

Despite the increasing interest in spring-fed fens’ sediments as a palaeoenvironmental archive, their potential as high-precision climatic records is rarely used to its full extent. Here, we present a detailed early to mid-Holocene record of environmental changes in the Turtul hanging spring-fed fen, northeastern Poland, to test whether the well preserved and accurately subsampled alternating peat and tufa sediments allow us to recognise short-duration local and regional climatic changes. Our reconstructions are based on a loss-on-ignition analysis of the sediment, carbon and oxygen stable isotope values of tufa, and biotic proxies: plant macrofossil and malacological analyses. A detailed environmental reconstruction was possible due to the combination of detailed sampling (1 cm intervals) and high sediment accumulation rates. The two sediment sequences collected from the fen revealed the congruent palaeoenvironmental history; however, the temporal shift associated with the distance of the coring site from the water outflow was also apparent, stressing the need for careful selection of the coring site in palaeoenvironmental research. Peat deposition at Turtul started at 10,300 cal yr BP; however, tufa precipitation did not begin before 9250 cal yr BP. During the most active tufa deposition, from 7850 to 6100 cal yr BP, a high sedimentation rate was observed (0.11–0.25 cm yr⁻¹). We found several abrupt and short-duration declines in carbonate deposition corresponding to climatic fluctuations recorded in geological archives from the southeastern Baltic region. The carbonate drops at 8200–8130, 7900–7850, 7400–7300, 6600–6500, 5980–5870 and 5400 cal yr BP were associated with climate cooling or drying, whereas those at 10,200–9250, 8450–8340 and 6160–6100 cal yr BP can be attributed to drying with no cooling. We conclude that the evident sensitivity of the Turtul fen to climatic shifts that emerge from our high-resolution (one sample every 17 years on average) reconstruction complements the still rare high-resolution palaeoenvironmental records in the area.

Historical salmon catch records suggest that climatic variability, and more recently human exploitation, control patterns of abundance in Atlantic salmon populations. We present the first long-term (2000-year) reconstruction of Atlantic Salmon population variations based on a Marine Derived Nutrient (MDN) lake sediment record. Our record is constructed from nitrogen isotopes (δ¹⁵N) measured from a lake sediment core, which we compare with an escapement index (EI) derived from historic net catch data on major Scottish salmon rivers. We used an isotope mixing model to demonstrate that the N isotope values are likely enriched with MDN and demonstrate that Loch Insh sediments are enriched compared with a control site (Loch Vaa) that has never had exposure to salmon. We demonstrate that current adult spawner returns are around half that of historic values prior to major human exploitation. Before the onset of widespread human exploitation and habitat degradation, large fluctuations in salmon abundance are attributed to variations in North Atlantic sea surface temperature. While our data support published reconstructions of declining Atlantic salmon stocks in Northwest European rivers over the last 1000 years, rather than point to a solely human cause, the human impact appears to be overprinted on larger-scale changes in marine habitat occurring at the transition from the warmer Medieval Climatic Anomaly (MCA) to the cooler Little Ice Age (LIA).

This study focuses on the analysis of wood charcoal from Cova del Vidre (Roquetes, Tarragona, Spain). This cave, located at an altitude of 1000 m a.s.l., is a key site for understanding the transition from hunting and gathering to farming in a mountainous region of north-eastern Iberia so far unexplored by archaeobotany. The anthracological study is based on four archaeological levels from the Epipalaeolithic to the Early Neolithic dated between 12.9 and 6.8 kyr cal BP, that is, from the Late Glacial period to the Middle Holocene. During the Younger Dryas, the record is dominated by a little varied spectrum of cryophilous pines (Pinus tp. sylvestris) and thorny shrubs revealing an open landscape where Prunus may prefigure the spread of temperate taxa. In the Early Holocene, a significant change in temperature and precipitation is evidenced, which promoted successional changes in plant communities, with a decline of pine and the sudden rise of temperate/Mediterranean taxa, such as Prunus and Quercus coccifera/ilex. During the Middle Holocene, other temperate taxa appear, such as Quercus deciduous, Buxus sempervirens and Taxus baccata, with yew finally dominating the anthracological record. The appearance and early development of temperate or Mediterranean species as early as the Younger Dryas and the Early Holocene periods, in a mountain context that had long been favourable for Scots pine, allows us to argue the local existence of a glacial refugium. Differences with the nearby sites in the lowlands demonstrate that altitudinal differences in vegetation were already established in the Holocene. Furthermore, the site helps to define the palaeodistribution of Taxus baccata, Abies alba and Fagus sylvatica in southern Europe.

Here we have analysed the Holocene mollusc successions in the valleys of the Talaya and Bartat rivers (Krasnoyarsk forest-steppe), which, based on three radiocarbon dates, cover at least the last 6000 years. By studying more than 8700 mollusc shells, we aimed to reconstruct the development of alluvial conditions. Existing palynological data from the nearby Eleneva Cave provide deeper insights into the reconstruction of habitat conditions. A total of 13 freshwater and 18 terrestrial mollusc species were identified. Some of the land snail species are the first records for the region, with the finding of Vertigo substriata pushing its distribution limit eastward. The Talaya sequence consisted of five successional stages recognised based on Coniss analysis. The major successional pathway in the mollusc record reflects an increase in temperature and fluctuations in precipitation during the Middle Holocene. Over time, an abundant assemblage of freshwater molluscs was gradually replaced by the dominance of open-country and wetland terrestrial snails. In contrast, cooling at the beginning of the Late-Holocene resulted in a reduction in terrestrial snail species diversity at the expense of aquatic molluscs, again indicating increased moisture in riparian habitats. Although the Bartat River succession covered only the last 600 years, it showed a fairly stable mollusc community composition with some terrestrialization observed in the most recent part of the succession.

This paper presents the results of an archaeological investigation into anthropogenic earth (oven) mounds located on the Murray River floodplain at Calperum Station in the Renmark region of South Australia. Six mounds were excavated and their contents examined. Sediment analyses were also conducted to assess magnetic susceptibility, grain size and loss on ignition. Radiocarbon age estimates were obtained on shell and charcoal. Mound contents primarily included anthropogenically burnt clay (heat retainers), charcoal, fragments of mussel shell as well as very minor quantities of other faunal material and stone artefacts (which were consistent with previous lithic assessments for the region). The radiocarbon age determinations from 15 samples indicate that mounds were formed by Aboriginal people on the Calperum floodplain from at least 3981–3723 cal BP and utilised up to the time of European invasion. The very minimal amount of faunal remains (other than mussel shell), artefacts and a general lack of other material evidence apart from clay heat retainers, confirms that these features were single purpose and not used as living areas. Sediment analyses and radiocarbon dates indicate a high degree of homogeneity within mounds but provide insights into an economic transition on the Calperum floodplain, at around 4000 cal BP involving a food-production procurement strategy based on heat retainer technology and the exploitation of emergent macrophytes.

Palynology is one of the most reliable tools for the reconstruction of past vegetation and climate and modern pollen analogues are important for the calibration of fossil pollen assemblages. The present study analyses the pollen–vegetation relationships along a steep altitudinal gradient (2700–3680 m), in the western Higher Himalayan region. On the basis of altitude, three vegetation zones were demarcated: Zone I (2700–3100 m) is composed of mixed-temperate forest vegetation, dominated by Quercus semecarpifolia and Rhododendron arboreum; Zone II (3100–3250 m) is marked by sub-alpine forest vegetation, characterised by R. campanulatum and R. barbatum, along with Abies spectabilis and Q. semecarpifolia; Zone III (3250–3680 m) is above the tree-line (3250 m) and represented by alpine-scrub and meadows. Thirty-five surface soil samples (twenty, seven and eight from each zone, respectively) were analysed along the altitudinal transect to decode the representation of the extant vegetation in the pollen-rain. The pollen–vegetation relationship is non-linear due to the over-representation of extra-local Pinus pollen in each zone. Nonetheless, the modern pollen assemblages show a general correlation with the local broad-leaved taxa and the herbaceous elements; with the exception of Rhododendron pollen, which is under-represented. Among the non-pollen palynomorphs (NPPs), the presence of coprophilous fungal spores is compatible with the grazing activities in the area. Multivariate statistical analyses performed on the surface pollen data indicate that the dataset can efficiently distinguish the different vegetation zones across the altitudinal gradient. This work provides the modern analogues for pollen-based palaeoclimatic reconstructions for the Western-Higher Himalayan region, and would also help to decipher the inception and intensification of anthropogenic activities in the region.

In the current global warming phase, relict glacial areas are one of the most threatened ecosystems in the world. They are “cold-spots” of biodiversity and of great interest both from the ecological and conservation point of view. We investigated the biological communities (plants and arthropods) hosted by one of the southernmost European glaciers: Calderone Glacier, the last preserved glacier of the Apennines mountain chain (Italy). We analyzed supraglacial debris and the nearby moraine and we found a rather diverse and peculiar biodiversity, which includes also new species. Some arthropods, such as the springtail Desoria calderonis, are particularly sensitive to the presence of ice at microtopographic level. Among plants, only Arabis alpina caucasica is able to grow on the supraglacial debris, perhaps because of factors related to the seed germination and seedling survival on this habitat type. Calderone glacier, with its particular biogeographic location, is probably currently acting as one of the last refugia for rare and endemic cryophilic species within the Mediterranean Region during the ongoing warm period.

This paper revises paleoenvironmental data from Patagonia (southern South America) to discuss the occurrence, characteristics, and human impact of the Medieval Climatic Anomaly (MCA). The analysis of continuous paleoenvironmental archives with multidecadal-to-centennial resolution is based on a quality assessment regarding data interpretation, chronological control, and time range adequacy within the MCA lapse. After applying this three-stepped quality filters on the total dataset (N = 48), 18 cases can accurately be ascribed to the MCA. Except for two sites indicating wetter conditions, these records show dry and/or warm conditions between ca. 750 and 1350 CE (core period at ca. 800–1200 CE). Even though MCA records come mostly from forests and forest-steppe ecotones, all previous archeological hypotheses about the MCA effects on past hunter-gatherers were proposed for the steppes, particularly in southern sectors, thus requiring an assessment of the source of the signal, their synchronicity and causality between human-environmental processes. In the southern steppe, paleoenvironmental records partially overlapping with the MCA time window actually show a predominance of wet conditions between 47° and 50° S, whereas a generalized aridity is recorded in southern tip of the continental Patagonia between 51° and 52° S. Thus, a complex scenario of landscape fragmentation can be supported in the southern steppes during the MCA, produced not only by enhanced aridity in dry environments, but also because of the presence of wet and more resilient areas. This landscape heterogeneity must be considered to deepen the understanding of behavioral changes contemporaneous to the MCA. However, a scenario of demographic growth suggested around 1000 CE for the entire Patagonia could have promoted human changes similar to those expected for the MCA. Finally, no-archeological discussions linked to the MCA were developed for forest regions, despite their robust paleoenvironmental records, implying that changes in proxy data might not have necessarily involved important environmental changes.

The Holocene is defined by the impact of agricultural societies on their natural environments and resources, a paradigmatic shift triggered by the Agricultural Revolution. In Cantabrian Spain, the adoption of a sedentary economy (ca. 7000 cal yr BP) remains misunderstood, with contemporary Mesolithic and Neolithic sites apparently random dispersed. Energy Regimes, a time-independent and functional analysis of past societies, considers two cultures that cohabit and/or cooperate, based on their differential pattern of use of energy and resources, as well as on the variation in land-use strategies. We test and implement the framework of Energy Regimes through a targeted review, to examine the hunter-gatherer subsistence strategies in Cantabrian Spain. Archeological proxies such as demography, mobility, complexity of society, economy, and overexploitation of resources identified in 95 articles and books, allow us to apply Energy Regimes to reexamine transitions in hunter-gatherer societies. Neolithization in Cantabrian Spain is the result of a long process that started with the Solutrean cultural phase ca. 24,000 cal yr BP, during the Last Glacial Maximum. Hunter-gatherers developed onward novel subsistence strategies with subtle changes in energy use until the transition toward a sedentary economy. Energy Regimes provide new insights for other regional contexts where time-bounded analyses conceal the complexity of energy transition processes in Europe and beyond.