scholarly journals River sediments

2012 ◽  
Vol 370 (1966) ◽  
pp. 2093-2122 ◽  
Author(s):  
Martin Williams
Keyword(s):  
Environmental Changes ◽  
Human Impacts ◽  
Eastern Mediterranean ◽  
River Sediments ◽  
Solar Insolation ◽  
Flood Plains ◽  
The Past ◽  
History Of ◽  
Floods And Droughts ◽  
Global Fluctuations

River history is reflected in the nature of the sediments carried and deposited over time. Using examples drawn from around the world, this account illustrates how river sediments have been used to reconstruct past environmental changes at a variety of scales in time and space. Problems arising from a patchy alluvial record and from influences external to the river basin can make interpretation difficult. The Nile is treated in some detail because its history is further complicated by tectonic, volcanic and climatic events in its headwaters and by enduring human impacts. It arose soon after 30 Ma. Since that time approximately 100 000 km 3 of rock have been eroded from its Ethiopian sources and deposited in the eastern Mediterranean, with minor amounts of sediment laid down along its former flood plains in Egypt and Sudan. From these fragmentary alluvial remains, a detailed history of Nile floods and droughts has been reconstructed for the last 15 kyr, and, with less detail, for the past 150 kyr, which shows strong accordance with global fluctuations in the strength of the summer monsoon, which are in turn perhaps modulated by changes in solar insolation caused by changes in the Earth's orbit and by variations in solar irradiance.

Climate and environmental context of the Mongol invasion of Syria and defeat at ‘Ayn Jālūt (1258–1260 CE)

Erdkunde ◽  
2021 ◽  
Vol 75 (2) ◽  
pp. 87-104
Author(s):  
Nicola Di Cosmo ◽  
Sebastian Wagner ◽  
Ulf Büntgen
Keyword(s):  
Strategic Alliances ◽  
Turning Point ◽  
Environmental Changes ◽  
Environmental Variability ◽  
State Of The Art ◽  
Eastern Mediterranean ◽  
The Caucasus ◽  
Mountainous Regions ◽  
The Past ◽  
Climate Reconstructions

After a successful conquest of large parts of Syria in 1258 and 1259 CE, the Mongol army lost the battle of 'Ayn Jālūt against Mamluks on September 3, 1260 CE. Recognized as a turning point in world history, their sudden defeat triggered the reconfiguration of strategic alliances and geopolitical power not only in the Middle East, but also across much of Eurasia. Despite decades of research, scholars have not yet reached consensus over the causes of the Mongol reverse. Here, we revisit previous arguments in light of climate and environmental changes in the aftermath of one the largest volcanic forcings in the past 2500 years, the Samalas eruption ~1257 CE. Regional tree ring-based climate reconstructions and state-of-the-art Earth System Model simulations reveal cooler and wetter conditions from spring 1258 to autumn 1259 CE for the eastern Mediterranean/Arabian region. We therefore hypothesize that the post-Samalas climate anomaly and associated environmental variability affected an estimated 120,000 Mongol soldiers and up to half a million of their horses during the conquest. More specifically, we argue that colder and wetter climates in 1258 and 1259 CE, while complicating and slowing the campaign in certain areas, such as the mountainous regions in the Caucasus and Anatolia, also facilitated the assault on Syria between January and March 1260. A return to warmer and dryer conditions in the summer of 1260 CE, however, likely reduced the regional carrying capacity and may therefore have forced a mass withdrawal of the Mongols from the region that contributed to the Mamluks’ victory. In pointing to a distinct environmental dependency of the Mongols, we offer a new explanation of their defeat at 'Ayn Jālūt, which effectively halted the further expansion of the largest ever land-based empire.

Small peatland with a big story: 600-year paleoecological and historical data from a kettle-hole peatland in Western Russia

The Holocene ◽  
2021 ◽  
pp. 095968362110332
Author(s):  
Agnieszka Mroczkowska ◽  
Piotr Kittel ◽  
Katarzyna Marcisz ◽  
Ekaterina Dolbunova ◽  
Emilie Gauthier ◽  
...  
Keyword(s):  
Human Impact ◽  
Human Activities ◽  
Environmental Changes ◽  
Climatic Variability ◽  
Testate Amoebae ◽  
The Past ◽  
Kettle Hole ◽  
Rapid Changes ◽  
History Of ◽  
Physical And Chemical

Peatlands are important records of past environmental changes. Based on a multiproxy analysis, the main factors influencing the evolution of a peatland can be divided into autogenic and allogenic. Among the important allogenic factors, apart from climate change, are deforestation and drainage, which are directly associated with human impact. Numerous consequences arise from these processes, the most important of which are physical and chemical denudation in the catchment and the related hydrological disturbances in the catchment and peatland. The present study determined how human activities and the past climatic variability mutually influenced the development of a small peatland ecosystem. The main goals of the study were: (1) to trace the local changes of the peatland history over the past 600 years, (2) to investigate their relationship with changes in regional hydroclimate patterns, and (3) to estimate the sensitivity of a small peatland to natural and human impact. Our reconstructions were based on a multiproxy analysis, including the analysis of pollen, macrofossils, Chironomidae, Cladocera, and testate amoebae. Our results showed that, depending on the changes in water level, the history of peatland can be divided into three phases as follows: 1/the phase of stable natural conditions, 2/phase of weak changes, and 3/phase of significant changes in the catchment. Additionally, to better understand the importance of the size of catchment and the size of the depositional basin in the evolution of the studied peatland ecosystem, we compared data from two peatlands – large and small – located close to each other. The results of our study indicated that “size matters,” and that larger peatlands are much more resilient and resistant to rapid changes occurring in the direct catchment due to human activities, whereas small peatlands are more sensitive and perfect as archives of environmental changes.

Resilience of plant and testate amoeba communities after climatic and anthropogenic disturbances in a Baltic bog in Northern Poland: Implications for ecological restoration

The Holocene ◽  
2016 ◽  
Vol 27 (1) ◽  
pp. 130-141 ◽  
Author(s):  
Mariusz Gałka ◽  
Kazimierz Tobolski ◽  
Aleksandra Górska ◽  
Mariusz Lamentowicz
Keyword(s):  
Human Impacts ◽  
Testate Amoebae ◽  
Ice Age ◽  
Testate Amoeba ◽  
Raised Bogs ◽  
The Past ◽  
Ombrotrophic Peatland ◽  
History Of ◽  
Climate Cooling

This study explores the history of the development of Sphagnum communities in an ombrotrophic peatland – Bagno Kusowo – over the past 650 years, based on high-resolution plant macrofossil and testate amoebae analysis. Our research provided information related to the length of peatland existence and the characteristics of its natural/pristine state before the most recent human impacts. Changes in the Sphagnum communities before human impact could have resulted from climate cooling during the ‘Little Ice Age’ (LIA). In this cold and unstable hydrological period, among vascular plants, Eriophorum vaginatum and Baeothryon caespitosum dominated in the peatland vegetation. Peat-forming Sphagnum communities survived the drainage conducted during the 20th century at the Bagno Kusowo bog. We provide three important messages through this study: (1) testate amoebae reflect similar hydrological trends in two peat cores despite considerable microhabitat variability, (2) average long-term water level 10 cm below the surface should be a target for active bog conservation and (3) sites like Bagno Kusowo are extremely important to preserve the remains of pristine biodiversity (including genetic diversity of plants and protists) that was completely removed from most of the raised bogs in Europe due to human activities, for example, drainage.

scholarly journals Archaeogenetics and Landscape Dynamics in Sicily during the Holocene: A Review

2021 ◽  
Vol 13 (17) ◽  
pp. 9469
Author(s):  
Valentino Romano ◽  
Giulio Catalano ◽  
Giuseppe Bazan ◽  
Francesco Calì ◽  
Luca Sineo
Keyword(s):  
Environmental Changes ◽  
Population History ◽  
Mediterranean Islands ◽  
Ecological Constraints ◽  
Cultural Changes ◽  
The Holocene ◽  
The Past ◽  
History Of ◽  
History Of Europe ◽  
Future Management

The Mediterranean islands and their population history are of considerable importance to the interpretation of the population history of Europe as a whole. In this context, Sicily, because of its geographic position, represents a bridge between Africa, the Near East, and Europe that led to the stratification of settlements and admixture events. The genetic analysis of extant and ancient human samples has tried to reconstruct the population dynamics associated with the cultural and demographic changes that took place during the prehistory and history of Sicily. In turn, genetic, demographic and cultural changes need to be understood in the context of the environmental changes that took place over the Holocene. Based on this framework, this paper aims to discuss the cultural and demographic dimension of the island by reviewing archaeogenetic studies, and lastly, we discuss the ecological constraints related to human peopling in times of change in landscapes that occurred on the island in various periods. Finally, possible directions for future archaeogenetic studies of Sicily are discussed. Despite its long human history, Sicily is still one of the world’s biodiversity hotspots. The lessons we learn from the past use of landscape provide models for sustainable future management of the Mediterranean’s landscapes.

Trial-by-Trial Updating of the Gain in Preparation for Smooth Pursuit Eye Movement Based on Past Experience in Humans

2008 ◽  
Vol 99 (2) ◽  
pp. 747-758 ◽  
Author(s):  
Hiromitsu Tabata ◽  
Kenichiro Miura ◽  
Kenji Kawano
Keyword(s):  
Smooth Pursuit ◽  
Environmental Changes ◽  
Preceding Trial ◽  
Smooth Pursuit Eye Movements ◽  
First Order ◽  
Pursuit Eye Movements ◽  
The Past ◽  
History Of ◽  
Tracking Movements ◽  
Past Experiences

To understand how the CNS uses past experiences to generate movements that accommodate minute-by-minute environmental changes, we studied the trial-by-trial updating of the gain for initiating smooth pursuit eye movements and how this relates to the history of previous trials. Ocular responses in humans elicited by a small perturbing motion presented 300 ms after appearance of a target were used as a measure of the gain of visuomotor transmission. After the perturbation, the target was either moved horizontally (pursuit trial) or remained in a stationary position (fixation trial). The trial sequence randomly included pursuit and fixation. The amplitude of the response to the perturbation was modulated in a trial-by-trial manner based on the immediately preceding trial, with preceding fixation and pursuit trials decreasing and increasing the gain, respectively. The effect of the previous trial was larger with shorter intertrial intervals, but did not diminish for at least 2,000 ms. A time-series analysis showed that the response amplitude was significantly correlated with the past few trials, with dynamics that could be approximated by a first-order linear system. The results suggest that the CNS integrates recent experiences to set the gain in preparation for upcoming tracking movements in a changing environment.

scholarly journals Continuing Environmental Change - An Example from Nova Scotia

2004 ◽  
Vol 118 (1) ◽  
pp. 39 ◽  
Author(s):  
Edmund S. Telfer
Keyword(s):  
Nova Scotia ◽  
Environmental Changes ◽  
Human Impacts ◽  
Castor Canadensis ◽  
Dermacentor Variabilis ◽  
Fagus Grandifolia ◽  
Past Century ◽  
Lynx Lynx ◽  
The Past ◽  
Severe Reduction

Information from personal experience, from community elders and published literature served as a basis for evaluating environmental changes in the District of North Queens and adjacent areas of Southwestern Nova Scotia over the past century. Major events included disappearance of the Caribou (Rangifer tarandus), the arrival of White-tailed Deer (Odocoileus virginianus), the severe reduction of Canada Yew (Taxus canadensis), disappearance of Lynx (Lynx canadensis), a major dieoff of Striped Skunks (Mephitis mephitis), decline of American Beech (Fagus grandifolia), the loss of mature birch (Betula spp.), the severe reduction of Moose (Alces alces), the arrival of the American Dog Tick (Dermacentor variabilis) and Coyotes (Canis latrans), and the restoration of Beaver (Castor canadensis). The proximate cause of many of those changes were plant and animal disease, while the ultimate causes were naturally occurring animal range expansion and human impacts. The warming of the climate over the past 150 years probably played a role. The nature and timing of the events could not have been predicted.

The Oxford Handbook of Historical Ecology and Applied Archaeology

2015 ◽  
Keyword(s):  
Case Studies ◽  
Historical Ecology ◽  
Historical Data ◽  
Human Impacts ◽  
Resource Exploitation ◽  
The Past ◽  
Development Policies ◽  
History Of ◽  
Applied Archaeology

This volume presents theoretical discussions, methodological outlines, and case-studies describing the discursive overlap of the theoretical and methodological framework of historical ecology, and the emerging sub-discipline of applied archaeology. Historical ecology is based on the recognition that humans are not only capable of modifying their environments, but that all environments on earth have already been directly or indirectly modified. This includes anthropogenic climate change, widespread deforestations, and species extinctions, but also very local alterations, the effects of which may last a few years, or may have legacies lasting centuries or more. The volume presents a range of case-studies that highlight how modern environments and landscapes have been shaped by humans, and includes outlines of the methods we can use to better understand these changes. Authors include anthropologists, archaeologists, human geographers, and historians, all of whom are focussed not just on defining human impacts in the past, but on the ways that understanding these changes can help inform contemporary practices and development policies. Some present examples of how ancient or current societies have modified their environments in sustainable ways, while others highlight practices that had unintended long-term consequences. The possibility of learning from these practices are discussed, as is the potential of using the long history of human resource exploitation as a method for building or testing models of future change. Rather than merely acting as advocates for historical data, the chapters collected here also warn of the limitations of drawing simple lessons from the history of interactions between humans and their environments, and note that doing so is potentially just as damaging as ignoring these rich sources of data.

Paleoenvironmental Changes during the Last 4000 yr in the Tigray, Northern Ethiopia

1998 ◽  
Vol 49 (3) ◽  
pp. 312-321 ◽  
Author(s):  
Maria J. Machado ◽  
Alfredo Pérez-González ◽  
Gerardo Benito
Keyword(s):  
Sediment Yield ◽  
Environmental Changes ◽  
Human Impacts ◽  
17Th Century ◽  
Northern Ethiopia ◽  
Paleoenvironmental Reconstruction ◽  
Tigray Region ◽  
The Past ◽  
Paleoenvironmental Changes ◽  
Paleoclimatic Data

In the Tigray region at the northern Ethiopian Highlands, paleoenvironmental reconstruction based on several infilled valley deposit sequences suggests that the past 4000 yr comprised three major wetter periods (ca. 4000–3500 yr B.P., 2500–1500 yr B.P., and 1000–960 yr B.P.), during which soils were formed, and two degradation episodes (ca. 3500–2500 yr B.P. and 1500–1000 yr B.P.), during which there was an increase of sediment yield from the slopes into the valleys. For the past 1000 yr, and in particular since the early 17th century, stratigraphic records together with historic chronicles suggest increasing aridity. Although difficulties arise in distinguishing between natural and human impacts, particularly in a region with a long established agricultural background, stratigraphical and proxy paleoclimatic data have indicated climate as the main controlling factor responsible for the environmental changes in the Tigray.

scholarly journals Multilocus Species Trees Show the Recent Adaptive Radiation of the Mimetic Heliconius Butterflies

2014 ◽  
Author(s):  
Krzysztof M Kozak ◽  
Niklas Wahlberg ◽  
Andrew Neild ◽  
Kanchon K Dasmahapatra ◽  
James Mallet ◽  
...  
Keyword(s):  
Adaptive Radiation ◽  
Rate Increase ◽  
Environmental Changes ◽  
Species Trees ◽  
Nuclear Markers ◽  
Continental Scale ◽  
The Past ◽  
History Of ◽  
Methodological Approaches ◽  
Mitochondrial And Nuclear Markers

Müllerian mimicry among Neotropical Heliconiini butterflies is an excellent example of natural selection, and is associated with the diversification of a large continental-scale radiation. Some of the processes driving the evolution of mimicry rings are likely to generate incongruent phylogenetic signals across the assemblage, and thus pose a challenge for systematics. We use a dataset of 22 mitochondrial and nuclear markers from 92% of species in the tribe to re-examine the phylogeny of Heliconiini with both supermatrix and multi-species coalescent approaches, characterise the patterns of conflicting signal and compare the performance of various methodological approaches to reflect the heterogeneity across the data. Despite the large extent of reticulate signal and strong conflict between markers, nearly identical topologies are consistently recovered by most of the analyses, although the supermatrix approach fails to reflect the underlying variation in the history of individual loci. The first comprehensive, time-calibrated phylogeny of this group is used to test the hypotheses of a diversification rate increase driven by the dramatic environmental changes in the Amazonia over the past 23 million years, or changes caused by diversity-dependent effects on the rate of diversification. We find that the tribe Heliconiini had doubled its rate of speciation around 11 Ma and that the presently most speciose genus Heliconius started diversifying rapidly at 10 Ma, likely in response to the recent drastic changes in topography of the region. Our study provides comprehensive evidence for a rapid adaptive radiation among an important insect radiation in the most biodiverse region of the planet.

Peatland evolution and associated environmental changes in central China over the past 40,000 years

2015 ◽  
Vol 84 (2) ◽  
pp. 255-261 ◽  
Author(s):  
Yuxin He ◽  
Cheng Zhao ◽  
Zhuo Zheng ◽  
Zhonghui Liu ◽  
Ning Wang ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Environmental Changes ◽  
Central China ◽  
The Past ◽  
Monsoonal Precipitation ◽  
Moisture Balance ◽  
History Of ◽  
Precipitation Changes ◽  
Dajiuhu Peatland ◽  
The Last Glacial

Central China has experienced stronger summer monsoon during warm periods such as Marine Isotope Stages (MIS) 1 and 3, and weaker summer monsoon during cool periods such as MIS 2. The evolution history of Dajiuhu subalpine peatland in central China can help investigate how the expansion and shrinkage of peatland were associated with monsoonal strength over the last glacial–interglacial cycle. Here we apply bulk organic carbon and molecular biomarkers (hopane and n-alkane) to reconstruct the evolution history for the Dajiuhu peatland over the past 40,000 yr. The results indicate fluctuations between lacustrine and peat-like deposition during MIS 3, steady lacustrine deposition during MIS 2, and peatland initiation and expansion during MIS 1 in the Dajiuhu peatland. Therefore, at the glacial–interglacial scale, warmer summer and cooler winter conditions in interglacial periods are crucial to trigger peat deposition, whereas reduced evaporation in glacial period instead of decreased monsoonal-driven precipitation would have played a predominant role in the regional effective moisture balance. However, within the Holocene (MIS 1), monsoonal precipitation changes appear to be the main controller on millennial-scale variations of water-table level of the Dajiuhu peatland.

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