Tree line shifts, changing vegetation assemblages and permafrost dynamics on Galdhøpiggen (Jotunheimen, Norway) over the past ~4400 years

The Holocene ◽  
2021 ◽  
pp. 095968362110665
Author(s):  
Helen Hallang ◽  
Cynthia A Froyd ◽  
John F Hiemstra ◽  
Sietse O Los
Keyword(s):  
Scots Pine ◽  
Late Holocene ◽  
Accumulation Rate ◽  
Climatic Changes ◽  
Climatic Conditions ◽  
Tree Line ◽  
Peat Core ◽  
Modern Pollen ◽  
Modern Analogue ◽  
Downy Birch

An environmental reconstruction based on palynological evidence preserved in peat was carried out to examine late-Holocene alpine tree line dynamics in the context of past climatic changes on Galdhøpiggen (Jotunheimen, southern Norway). We analysed a peat core taken from a mire at the present-day tree line (1000 m a.s.l.), c. 450 m downslope from the lower limit of sporadic permafrost. We adopted a combination of commonly used indicators of species’ local presence to reconstruct past vegetation assemblages, such as the relative pollen abundance (%), pollen accumulation rate (PAR), and presence of indicator species. Additionally, fossil pollen from the peat sequence was compared to modern pollen from a surface moss polster to establish a modern analogue. The results were compared with studies covering the late-Holocene climatic changes in the area. The reconstruction demonstrates that a pine-dominated woodland reached above the present-day tree line at c. 4300 cal. yr BP, suggesting a warmer climate suitable for Scots pine ( Pinus sylvestris) growth at this altitude. Scots pine retreated to lower altitudes between c. 3400 and 1700 cal. yr BP, accompanied by the descent of the low-alpine shrub-dominated belt, in response to cooling climatic conditions. The colder period covered c. 1700–170 cal. yr BP, and an open downy birch ( Betula pubescens) woodland became widespread at 1000 m a.s.l., whilst pine remained sparse at this altitude. From c. 170 cal. yr BP onwards, warming allowed pine to re-establish its local presence alongside downy birch at 1000 m a.s.l.

scholarly journals Scots pine (Pinus sylvestris) dynamics in the Welsh Marches during the mid to late-Holocene

The Holocene ◽  
2021 ◽  
pp. 095968362199465
Author(s):  
Dael Sassoon ◽  
William J Fletcher ◽  
Alastair Hotchkiss ◽  
Fern Owen ◽  
Liting Feng
Keyword(s):  
Pinus Sylvestris ◽  
Scots Pine ◽  
Late Holocene ◽  
British Isles ◽  
Loss On Ignition ◽  
Peat Core ◽  
New Information ◽  
Pine Trees ◽  
Pollen Records

Around 4000 cal yr BP, Scots pine ( Pinus sylvestris) suffered a widespread demise across the British Isles. This paper presents new information about P. sylvestris populations found in the Welsh Marches (western central Britain), for which the long-term history and origins are poorly known. Two new pollen records were produced from the Lin Can Moss ombrotrophic bog (LM18) and the Breidden Hill pond (BH18). The LM18 peat core is supported by loss-on-ignition, humification analysis and radiocarbon dating. Lead concentrations were used to provide an estimated timeframe for the recent BH18 record. In contrast to many other Holocene pollen records from the British Isles, analysis of LM18 reveals that Scots pine grains were deposited continuously between c. 6900–300 cal yr BP, at frequencies of 0.3–5.4%. It is possible that individual Scots pine trees persisted through the wider demise on thin soils of steep drought-prone crags of hills or the fringes of lowland bogs in the Welsh Marches. At BH18, the record indicates a transition from broadleaved to mixed woodland, including conifer species introduced around AD 1850 including Picea and Pinus. The insights from BH18 suggest that the current populations may largely be the result of planting. Comparison of the LM18 findings with other regional pollen records highlights consistent patterns, including a Mid-Holocene maximum (ca. 7000 cal yr BP), long-term persistence at low pollen percentages and a Late-Holocene minimum (ca. 3000 cal yr BP). These distinctive trends encourage further studies on refugial areas for Scots pine in this region and elsewhere.

Unstable Climate Oscillations during the Late Holocene in the Eastern Bransfield Basin, Antarctic Peninsula

2002 ◽  
Vol 58 (3) ◽  
pp. 234-245 ◽  
Author(s):  
Boo-Keun Khim ◽  
Ho Il Yoon ◽  
Cheon Yun Kang ◽  
Jang Jun Bahk
Keyword(s):  
Antarctic Peninsula ◽  
Late Holocene ◽  
Accumulation Rate ◽  
Silica Content ◽  
Climatic Conditions ◽  
Ice Age ◽  
Geochemical Data ◽  
Sediment Properties ◽  
Bransfield Basin ◽  
Distinct Features

AbstractCore A9-EB2 from the eastern Bransfield Basin, Antarctic Peninsula, consists of pelagic (diatom ooze-clay couplets and bioturbated diatom ooze) and hemipelagic (bioturbated mud) sediments interbedded with turbidites (homogeneous mud and silt–clay couplets). The cyclic and laminated nature of these pelagic sediments represents alternation between the deposition of diatom-rich biogenic sediments and of terrigenous sediments. Sediment properties and geochemical data explain the contrasting lamination, with light layers being finer-grained and relatively rich in total organic carbon and biogenic silica content. Also, the high-resolution magnetic susceptibility (MS) variations highlight distinct features: high MS values coincide with clastic-rich sections and low MS values correspond to biogenic sections. The chronology developed for core A9-EB2 accounts for anomalous ages associated with turbidites and shows a linear sedimentation rate of approximately 87 cm/103 yr, which is supported by an accumulation rate of 80 cm/103 yr calculated from 210Pb activity. The late Holocene records clearly identify Neoglacial events of the Little Ice Age (LIA) and Medieval Warm Period (MWP). Other unexplained climatic events comparable in duration and amplitude to the LIA and MWP events also appear in the MS record, suggesting intrinsically unstable climatic conditions during the late Holocene in the Bransfield Basin of Antarctic Peninsula.

Presence of lakes and wetlands decreases resilience of jack pine ecosystems to late-Holocene climatic changes

2014 ◽  
Vol 44 (11) ◽  
pp. 1331-1343 ◽  
Author(s):  
Elizabeth A. Lynch ◽  
Randy Calcote ◽  
Sara C. Hotchkiss ◽  
Michael Tweiten
Keyword(s):  
Pinus Banksiana ◽  
Late Holocene ◽  
Fire History ◽  
Climate Changes ◽  
Sediment Cores ◽  
Fire Regimes ◽  
Jack Pine ◽  
Climatic Changes ◽  
Climatic Conditions ◽  
Positive Feedbacks

We reconstructed vegetation and fire histories from four sites located on a sandy outwash plain in northwestern Wisconsin (USA) to test whether lakes and wetlands have influenced how vegetation and fire regimes in pine–oak forests responded to late-Holocene climatic changes. Because of positive feedbacks between jack pine (Pinus banksiana Lamb.) and fire, communities with few fire breaks should be more resilient to changing climatic conditions. Pollen and charcoal from lake-sediment cores were used to reconstruct vegetation changes at 50- to 100-year intervals and forest fire history at decadal time scales for the past 2500 years. The presence of fire breaks affected both fire regimes and the response of vegetation to climatic changes. Areas with more fire breaks had smaller charcoal peaks and the vegetation was more responsive to climate changes. The vegetation in areas with few fire breaks was more resilient, maintaining higher amounts of jack pine and (or) red pine than the more protected sites. We interpret these findings as evidence that positive feedbacks between fire and jack pine forests stabilized vegetation at sites where fire breaks were absent, and that such sites may be relatively resilient to future climate changes, until jack pine is no longer able to regenerate under the regional climatic conditions.

scholarly journals Bioinspired Living Coating System in Service: Evaluation of the Wood Protected with Biofinish during One-Year Natural Weathering

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 701
Author(s):  
Faksawat Poohphajai ◽  
Jakub Sandak ◽  
Michael Sailer ◽  
Lauri Rautkari ◽  
Tiina Belt ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Scots Pine ◽  
Critical Factor ◽  
Climatic Conditions ◽  
Natural Weathering ◽  
Surface Finishing ◽  
Attractive Alternative ◽  
Coating System ◽  
Self Healing ◽  
Wood Protection

The service life performance of timber products exposed to natural weathering is a critical factor limiting the broad use of wood as an external building element. The goal of this study was to investigate the in-service characterization of an innovative biofinish coating system. It is a novel surface finishing solution based on the bioinspired concept of living fungal cells designed for effective wood protection. The performance of Scots pine (Pinus sylvestris L.) wood coated with biofinish was compared with uncoated references. Samples were exposed to natural weathering for 12 months under the climatic conditions of northern Italy. The visual appearance, colour, gloss, wettability, and 3D surface topography of the wood surface were examined. Results revealed that the total colour changes (∆E) of biofinish-coated wood were negligible. Untreated Scots pine wood revealed the changes in colour after just three months of exposure. The gloss changes of both surface types were small. The contact angle measured on biofinish-coated wood was higher compared to that of uncoated Scots pine. Surface roughness increased in uncoated wood due to the erosion effect caused by the weathering progress. Conversely, the surface roughness of biofinish-coated samples decreased along the exposure time. This phenomenon was explained by two self-healing mechanisms: migration of non-polymerized oil to the cracked surface, where it polymerizes and creates a closed layer, and local regrowth to cover damaged spots by living fungal cells present in the coating. The obtained results revealed the superior aesthetic performance of the biofinish surface treatment against natural weathering. By considering the fully bio-based nature of the investigated coating, it was concluded that this solution can be an attractive alternative for state-of-the-art wood protection technologies.

scholarly journals FAME (v1.0): a simple module to simulate the effect of planktonic foraminifer species-specific habitat on their oxygen isotopic content

2018 ◽  
Vol 11 (9) ◽  
pp. 3587-3603 ◽  
Author(s):  
Didier M. Roche ◽  
Claire Waelbroeck ◽  
Brett Metcalfe ◽  
Thibaut Caley
Keyword(s):  
Late Holocene ◽  
Simple Module ◽  
Climatic Conditions ◽  
Model Data ◽  
Planktonic Foraminifer ◽  
Planktonic Foraminifers ◽  
Oxygen Isotopic ◽  
Species Specific ◽  
Almost All ◽  
Multiproxy Approach

Abstract. The oxygen-18 to oxygen-16 ratio recorded in fossil planktonic foraminifer shells has been used for over 50 years in many geoscience applications. However, different planktonic foraminifer species generally yield distinct signals, as a consequence of their specific living habitats in the water column and along the year. This complexity is usually not taken into account in model–data integration studies. To overcome this shortcoming, we developed the Foraminifers As Modeled Entities (FAME) module. The module predicts the presence or absence of commonly used planktonic foraminifers and their oxygen-18 values. It is only forced by hydrographic data and uses a very limited number of parameters, almost all derived from culture experiments. FAME performance is evaluated using the Multiproxy Approach for the Reconstruction of the Glacial Ocean surface (MARGO) Late Holocene planktonic foraminifer calcite oxygen-18 and abundance datasets. The application of FAME to a simple cooling scenario demonstrates its utility to predict changes in planktonic foraminifer oxygen-18 to oxygen-16 ratio in response to changing climatic conditions.

Human occupation strategies and related environmental-climate during the middle and late Holocene in central Pampas of Argentina

The Holocene ◽  
2018 ◽  
Vol 29 (2) ◽  
pp. 244-261 ◽  
Author(s):  
Pablo G Messineo ◽  
Marcela S Tonello ◽  
Silvina Stutz ◽  
Alfonsina Tripaldi ◽  
Nahuel Scheifler ◽  
...  
Keyword(s):  
Late Holocene ◽  
Specific Activity ◽  
Climatic Conditions ◽  
Hard Material ◽  
Human Occupation ◽  
Climate Conditions ◽  
Lithic Assemblage ◽  
Depositional Rate ◽  
Archeological Site ◽  
Middle And Late Holocene

The main objective of this work is to generate and integrate interpretations of human occupation strategies and inferences of the environmental-climatic conditions in the central Pampas during the middle and late Holocene. We present a novel archeological–geological–paleoecological analysis in the area of the Cabeza de Buey lake, placed in an aeolian landscape. During the middle Holocene, two events of human occupations were recognized at Laguna Cabeza de Buey 2 archeological site. Both events present a small amount of lithic materials, a low diversity of tools and activities developed with them (principally hard material), and the hunting and primary processing of artiodactyls. These evidences suggest a locus of specific activity associated with an ephemeral human settlement under climate conditions drier than present and the presence of small, brackish, and shallow water bodies. For the late late Holocene, the hunter-gatherer occupation has a higher depositional rate of lithic assemblage, stones with diverse origins, presence of pottery fragments, a great lithic tool diversity, knapping techniques, and activities developed with these tools (processing wood, bone, hide, non-woody plant, and soft material). These evidences reveal an occupation with a higher degree of recurrence represented by a locus of multiple activities associated with a more stable landscape, such as an environment of dunes fixed by grass vegetation, and the establishment of a permanent water body. The different environmental characteristics for the middle and late Holocene in this area promoted that human groups develop two different patterns of mobility, settlement and use of space.

scholarly journals Climate Change and Conflict

2019 ◽  
Vol 22 (1) ◽  
pp. 343-360 ◽  
Author(s):  
Vally Koubi
Keyword(s):  
Climate Change ◽  
Climatic Changes ◽  
Climatic Conditions ◽  
Future Research ◽  
General Effect ◽  
Substantial Agreement ◽  
Political Factors ◽  
Academic Literature ◽  
The Past ◽  
Level Of Economic Development

The link between climate change and conflict has been discussed intensively in academic literature during the past decade. This review aims to provide a clearer picture of what the research community currently has to say with regard to this nexus. It finds that the literature has not detected a robust and general effect linking climate to conflict onset. Substantial agreement exists that climatic changes contribute to conflict under some conditions and through certain pathways. In particular, the literature shows that climatic conditions breed conflict in fertile grounds: in regions dependent on agriculture and in combination and interaction with other socioeconomic and political factors such as a low level of economic development and political marginalization. Future research should continue to investigate how climatic changes interact with and/or are conditioned by socioeconomic, political, and demographic settings to cause conflict and uncover the causal mechanisms that link these two phenomena.

scholarly journals Verjüngungspotenzial verschiedener Waldföhrenund Fichtenherkünfte bei variabler Trockenheit

2015 ◽  
Vol 166 (6) ◽  
pp. 399-407 ◽  
Author(s):  
Barbara Moser ◽  
Marek Metslaid ◽  
Lorenz Walthert ◽  
Ulrich Wasem ◽  
Thomas Wohlgemuth
Keyword(s):  
Water Balance ◽  
Norway Spruce ◽  
Scots Pine ◽  
Weather Conditions ◽  
Climatic Conditions ◽  
Water Retention Capacity ◽  
Summer Drought ◽  
Retention Capacity ◽  
Rhine Valley ◽  
A Minor

Regeneration potential of different Scots pine and Norway spruce provenances under variable drought Rising temperatures will lead to extended periods of summer drought, which may challenge the persistence of Scots pine and Norway spruce in dry alpine valleys where these species play an important role in the protection against natural hazards. We tested whether the natural regeneration of the two species in the Rhine valley near Chur, Switzerland, might be limited under future climatic conditions and we compared the performance of autochthonous provenances with that of seedlings originating from regions with already drier summer climate such as the Rhone valley, continental Eastern Europe or the Mediterranean basin. Seeds of Scots pine and Norway spruce were sown repeatedly in forest clearings at three south-exposed sites in the Rhine valley near Chur, Switzerland. Soil moisture was manipulated to a minor extent with throughfall reduction roofs. In both species, regeneration success was primarily driven by the weather conditions during the three months following seed sowing: the seedlings having emerged in the rainy spring of 2013 had a higher survival rate and accumulated up to five times more aboveground biomass than the seedlings emerging in the dry spring of 2011. In years with an average or even positive water balance, Scots pine seedlings were able to establish at all sites. In Norway spruce, by contrast, establishment rate exceeded 10% of viable seeds only at the site with the highest water retention capacity. In years with a positive water balance during spring, the seedlings from the Rhine and Rhone valleys outperformed those from most Mediterranean and Eastern European provenances, while no differences between provenances were found in the dry spring of 2011. We suggest that periodical regeneration of Scots pine will be likely in the Rhine valley even under future climatic conditions, whereas the establishment of Norway spruce may remain an exceptional event in dry, south-exposed clearings.

scholarly journals Detection of Large Holocene Earthquakes in the Sedimentary Record of Wellington, New Zealand, Using Diatom Analysis

2021 ◽  
Author(s):  
◽  
Ursula Alyson Cochran
Keyword(s):  
New Zealand ◽  
Late Holocene ◽  
Weighted Averaging ◽  
Diatom Analysis ◽  
Sedimentary Record ◽  
Sedimentary Sequences ◽  
Quantitative Estimates ◽  
Modern Analogue ◽  
Environmental Transitions ◽  
Large Earthquakes

<p>New Zealand is situated on the boundary between the Pacific and Australian tectonic plates. The Wellington region lies near the southern end of the Hikurangi subduction zone and within a zone of major, active strike-slip faults. Wellington's paleoseismic and historic records indicate that large surface rupture earthquakes have occurred on these faults in the past. Development of a complete record of past large earthquakes is a high priority for the region because of the risk posed by occurrence of large earthquakes in the future. The existing paleoseismic record has been derived predominantly from studies of fault trench stratigraphy, raised beach ridges and offset river terraces. The sedimentary record of lakes and coastal waterbodies is a source of information that has not been used specifically for paleoseismic purposes in the region. Therefore investigation of Wellington's sedimentary record is used in this thesis to make a contribution to the paleoseismic record. Holocene sedimentary sequences are studied from three small, low elevation, coastal waterbodies: Taupo Swamp, Okupe Lagoon and Lake Kohangapiripiri. Sequences of between 200 and 650 cm depth were collected using a hand-operated coring device. Sedimentology and diatom microfossil content were analysed and interpreted to enable reconstruction of paleoenvironment at each site. Radiocarbon dating was used to provide chronologies for the sequences that are aged between 5000 and 7500 calibrated years before present (cal. years BP). Diatom analysis is the main tool used to reconstruct paleoenvironment and detect evidence for occurrence of past large earthquakes. To aid reconstruction of sedimentary sequences used in this project, as well as coastal sequences in New Zealand in general, a coastal diatom calibration set was constructed using 50 sites around New Zealand. Modern diatom distribution and abundance, and associated environmental variables are analysed using ordination and weighted averaging techniques. Detrended correspondence analysis arranges species according to salinity preferences and divides sites clearly into waterbody types along a coastal gradient. This analysis enables reconstruction of waterbody type from fossil samples by passive placement onto ordination diagrams. Weighted averaging regression of calibration set samples results in a high correlation (r2jack=0.84) between observed and diatom inferred salinity, and enables salinity preferences and tolerances to be derived for 100 species. This confirms for the first time that species' preferences derived in the Northern Hemisphere are generally applicable to diatoms living in the coastal zone of New Zealand. Weighted averaging calibration and the modern analogue technique are used to generate quantitative estimates of paleosalinity for fossil samples. Paleoenvironmental reconstructions of Taupo Swamp, Okupe Lagoon and Lake Kohangapiripiri indicate that each waterbody has been isolated from the sea during the late Holocene. Isolation has been achieved through interplay of sediment accumulation causing growth of barrier beaches, and coseismic uplift. Ten distinct transitions between different paleoenvironments are recognised from the three sequences. These transitions involve changes in relative sea level or water table level often in association with catchment disturbance or marine influx events. All transitions occur suddenly and are laterally extensive and synchronous within each waterbody. Quantitative estimates of paleosalinity and waterbody type are used to differentiate between large and small magnitude changes in paleoenvironment. Five transitions involve large amounts of paleoenvironmental change and provide evidence for earthquakes occurring at approximately 5200, approximately 3200, and approximately 2300 cal. years BP. Five other transitions are consistent with the effects of large earthquakes occurring at approximately 6800, 2200, approximately 1000, approximately 500 cal. years BP and 1855 AD but do not provide independent evidence of the events. Environmental transitions at Lake Kohangapiripiri clarify the timing of rupture of the Wairarapa Fault by bracketing incompatible age estimates derived from two different sites on the fault. The oldest environmental transitions recognised at Taupo Swamp and Okupe Lagoon both occur at approximately 3200 cal. years BP indicating that western Wellington was uplifted at this time. Environmental transitions are recorded at all three study sites at approximately 2300 cal. years BP indicating that the entire western and central Wellington region experienced coseismic uplift at this time. Because of the distance between sites this apparent synchroneity implies that several faults in the region ruptured at a similar time. Investigation of sedimentary sequences contributes to the existing paleoseismic record by providing additional estimates of timing for past large earthquakes, enabling estimation of the areal extent of the effects of past earthquakes, and by highlighting periods of fault rupture activity in the late Holocene.</p>

scholarly journals Geomorphological indicators of large-scale climatic changes in the Eastern Bolivian lowlands

2006 ◽  
Vol 61 (2) ◽  
pp. 120-134 ◽  
Author(s):  
J. May
Keyword(s):  
South America ◽  
Large Scale ◽  
Climate Changes ◽  
Landscape Evolution ◽  
Spatial Scales ◽  
Climatic Changes ◽  
Climatic Conditions ◽  
Fluvial Erosion ◽  
Paleoclimatic Significance ◽  
Bolivian Lowlands

Abstract. This study provides an inventory of geomorphological landforms in Eastern Bolivia at different spatial scales. Landforms and associated processes are interpreted and discussed regarding landscape evolution and paleoclimatic significance. Thereby, preliminary conclusions about past climate changes and the geomorphic evolution in Eastern Bolivia can be provided. Fluvial and aeolian processes are presently restricted to a few locations in the study area. A much more active landscape has been inferred from large-scale Channel shifts and extensive paleodune Systems. Mobilization. transport and deposition of Sediments are thought to be the result of climatic conditions drier than today. However. there are also indications of formerly wetter conditions such as fluvial erosion and paleolake basins. In conclusion, the documentation and interpretation of the manifold landforms has shown to contain a considerable amount of paleoecological information, which might serve as the base for further paleoclimatic research in the central part of tropical South America.

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