Search results for "SYSTEMATICS"

A 2500 year record of natural and anthropogenic soil erosion in South Greenland

2012

International audience; The environmental impact of the Norse landnám in Greenland has been studied extensively. But to date, no study has quantified the soil erosion that Norse agricultural practices are believed to have caused. To resolve this problem, a high resolution sedimentary record from Lake Igaliku in South Greenland is used to quantitatively reconstruct 2500 years of soil erosion driven by climate and historical land use. An accurate chronology allows for the estimation of detritic fluxes and their uncertainties. Land clearance and the introduction of grazing livestock by the Norse around 1010 AD caused an acceleration of soil erosion up to 8 mm/century in 1180 AD which is two-fo…

New palaeoecological approaches to interpret climatic fluctuations in Holocene sites of the Pampean region of Argentina

2021

The apparently regular and favourable climate that characterizes the Holocene as an interglacial period shows, however, important climatic instability well documented in the Northern Hemisphere. These fluctuations from colder to warmer or wetter to drier affected both biodiversity and human societies in the last 12,000 years, although the impact in Southern America is still poorly known. We are here investigating the biodiversity of small mammal faunas, more sensitive to climatic changes than large mammals, combining taphonomic and palaeoecological data in the Argentine Pampas to better understand the global nature and effect of these Holocene climatic fluctuations. This paper is pioneering…

Quantifying the evolution of animal dairy intake in humans using calcium isotopes

2021

International audience; The contribution of dairy products to modern human diets has a debated role in the expansion of Neolithic economies and the dynamics of demographic transitions. While current methods allow discussing dairy production and processing, no approach allows reconstructing quantitatively its effective consumption. Calcium isotopes (δ44/42Ca) potentially represent such a marker due to the abundance of isotopically fractionated Ca in dairy products. Here, we test Ca isotope sensitivity to dietary intake of dairy product: we first used a dietary model based on a compilation of available data of dietary Ca sources; we then compared the modelled outputs to available and newly ac…

A 1286‐year hydro‐climate reconstruction for the Balkan Peninsula

2018

We present a June-July drought reconstruction based on the standardized precipitation index (SPI) for the Balkan Peninsula over the period 730-2015 CE. The reconstruction is developed using a compo ...

Broadleaf deciduous forest counterbalanced the direct effect of climate on Holocene fire regime in hemiboreal/boreal region (NE Europe)

2017

Abstract Disturbances by fire are essential for the functioning of boreal/hemiboreal forests, but knowledge of long-term fire regime dynamics is limited. We analysed macrocharcoal morphologies and pollen of a sediment record from Lake Lielais Svētiņu (eastern Latvia), and in conjunction with fire traits analysis present the first record of Holocene variability in fire regime, fuel sources and fire types in boreal forests of the Baltic region. We found a phase of moderate to high fire activity during the cool and moist early (mean fire return interval; mFRI of ∼280 years; 11,700–7500 cal yr BP) and the late (mFRI of ∼190 years; 4500–0 cal yr BP) Holocene and low fire activity (mFRI of ∼630 y…

Multi-archive summer temperature reconstruction for the European Alps, AD 1053–1996

2012

We present a multi-archive, multi-proxy summer temperature reconstruction for the European Alps covering the period AD 1053e1996 using tree-ring and lake sediment data. The new reconstruction is based on nine different calibration approaches and errors were estimated conservatively. Summer temperatures of the last millennium are characterised by two warm (AD 1053e1171 and 1823e1996) and two cold phases (AD 1172e1379 and 1573e1822). Highest pre-industrial summer temperatures of the 12th century were 0.3 � C warmer than the 20th century mean but 0.35 � C colder than proxy derived

New tree-ring evidence for the Late Glacial period from the northern pre-Alps in eastern Switzerland

2018

Abstract The rate and magnitude of temperature variability at the transition from the Last Glacial Maximum into the early Holocene represents a natural analog to current and predicted climate change. A limited number of high-resolution proxy archives, however, challenges our understanding of environmental conditions during this period. Here, we present combined dendrochronological and radiocarbon evidence from 253 newly discovered subfossil pine stumps from Zurich, Switzerland. The individual trees reveal ages of 41–506 years and were growing between the Allerod and Preboreal (∼13′900–11′300 cal BP). Together with previously collected pines from this region, this world's best preserved Late…

2020

To place recent hydroclimate changes, including drought occurrences, in a long-term historical context, tree-ring records serve as an important natural archive. Here, we evaluate 46 millennium-long ...

Concord and discord among Northern Hemisphere paleotemperature reconstructions from tree rings

2019

Abstract We review the current generation of large-scale, millennial-length temperature reconstructions derived from tree rings and highlight areas of agreement and disagreement among these state-of-the-art paleotemperature estimates. Although thousands of tree ring-width chronologies are now available from temperate and boreal forest sites across the Northern Hemisphere, only a small fraction of those records are suited as proxies for surface temperature. Maximum latewood density is clearly a superior temperature proxy but is less available, with few densitometric records that are both long and up-to-date. Compared to previous efforts, the newest generation of tree-ring reconstructions cor…

Oxygen isotope analysis of Equus teeth evidences early Eemian and early Weichselian palaeotemperatures at the Middle Palaeolithic site of Neumark-Nor…

2019

Abstract Here we present phosphate oxygen isotope (δ 18OPO4) data from horse (Equus sp.) tooth enamel (bioapatite) from early Eemian and early Weichselian find levels at the archaeological site of Neumark-Nord 2, Germany. Based on the relationship between δ18OPO4 of bioapatite, body water, local precipitation and air temperature, these data are used to reconstruct palaeoclimatic conditions contemporary to the different phases of Neanderthal activity at the site. Bulk enamel samples representing one year of growth were taken from horse teeth from early Eemian (NN2/2b [∼121 ± 5 ka], and NN2/1c) and early Weichselian (NN2/0; ∼93 ± 7 ka) find levels, and δ18OPO4 values were then utilised to cal…