The Effect of Disturbance on Plant Communities in Tundra Regions of the Soviet Union

An Annotated List of Plants Inhabiting Sites of Natural and Anthropogenic Disturbances of Tundra Cover: Southeasternmost Chukchi Peninsula -- B.A. Yurtsev and A.A. Korobkov; An Annotated List of Plants Inhabiting Sites of Natural and Anthropogenic Disturbances of Tundra Cover in Western Taimyr: The Settlement of Kresty -- N.V. Matveyeva; A Study of Plant Communities of Anthropogenic Habitats in the Area of the Vorkuta Industrial Center -- O.A. Druzhinina and Yu. G. Zharkov

Ornamental Evergreens

PDF pages: 4

Dwarf tundra shrubs growth as a proxy for late Holocene climate change

The Arctic is the most sensitive zone to climate changes and the impacts are reflected in local ecosystems. In order to extract information of the past from proxy archives the detailed knowledge of such archive is crucial. The paper summarizes modern approaches of tundra dwarf shrub research for the purposes of paleoclimatology. Dwarf tundra shrubs as still relatively untapped archive are believed to contain valuable proxy data in their annual growth increments. Field sampling, and laboratory work are reviewed in detail. Constraints of dwarf tundra shrub research are discussed as well. The relationship between climate and growth is addressed to find a link between them depending on location and species. Majority of investigations found the strongest relationship between summer temperatures and ring widths, although exceptions are not rare. Dwarf tundra shrubs can fully serve as valuable proxy archive only if those are understood. Finally, the factors influencing the length of dwarf tundra shrub life are studied in order to sample the oldest living individuals in the field. Despite the field collection should aim to sample various sizes and ages of plants to make the dataset robust, the longest living individuals which are important to prolong chronologies are usually inhabiting rather nutrient poor and undisturbed sites close to their survival limits. The paper indicates the most suitable dwarf tundra shrub research designs for the purposes of paleoclimatology. As such it can help to harvest the benefits of dendrochronology from the vast and new territories

Combination of herbivore removal and nitrogen deposition increases upland carbon storage

© 2015 The Authors. Global Change Biology Published by John Wiley & Sons Ltd. Acknowledgements We thank Ruth Mitchell, Alison Hester, Bob Mardon, Eoghain Maclean, David Welch, National Trust for Scotland, Scottish Natural Heritage and the Woodland Trust for helping find appropriate exclosures and granting access permission. We thank Nick Littlewood and Antonio Lopez Nogueira for their assistance in the field and processing samples in the lab and Ron Smith and Tony Dore for providing N deposition data. SWS was funded by a BBSRC studentship.Non peer reviewedPublisher PD

Land use effects on soil organic carbon sequestration in calcareous Leptosols in former pastureland : a case study from the Tatra Mountains (Poland)

The purpose of the paper is to describe soil organic carbon (SOC) sequestration rates in calcareous shallow soils in reforested areas in the Tatra Mountains with a particular focus on different forms of organic matter (OM) storage. Three plant communities creating a mosaic on the slopes of the studied valley were taken into account. Fifty years since the conversion of pastureland to unused grassland, dwarf pine shrub and larch forest have emerged in the study area, along with the development of genetic soil horizons as well as SOC sequestration in the soil despite the steepness of slopes. SOC stock was measured to be the highest in soils under larch forest (63.5 Mg ha−1), while in soil under grassland and under dwarf pine shrub, this value was found to be smaller (47.5 and 42.9 Mg ha−1, respectively). The highest amount of mineral-associated OM inside stable microaggregates (MOM FF3) was found in grassland soil (21.9–27.1 % of SOC) and less under dwarf pine shrub (16.3–19.3 % of SOC) and larch forest (15.3–17.7 % of SOC). A pool of mineral-associated OM inside transitional macroaggregates (MOM FF2) was found in soil under dwarf pine shrub (39.2–59.2 % of SOC), with less under larch forest (43.8–44.7 % of SOC) and the least in grassland soil (37.9–41.6 % of SOC). The highest amount of the free light particulate fraction (POM LF1) was found in soil under dwarf pine shrub (6.6–10.3 % of SOC), with less under larch forest (2.6–6.2 % of SOC) and the least in grassland soil (1.7–4.8 % of SOC)

Evolution of postglacial vegetation in the Western Laptev Sea region (Siberian Arctic)

On the basis of a detailed study of the pollen-spore spectra and a detailed radiocarbon chronology of a sediment core obtained from the western outer Laptev Sea shelf, the long-term and high-resolution changes of vegetation in the northwestern Laptev Sea region were reconstructed for the last 12.0 cal. ka. Three major phases in the development of paleoenvironments and vegetation on the surrounding hinterland and the exposed Laptev Sea shelf were recognized. The period between 12.0 and 10.3 cal. ka BP was characterized by predominance of grass-sedge and moss tundra. Rapid expansion of herbaceous tundra with dwarf birch and alder started at about 10.3 and lasted until 8.0 cal. ka. Pollen spectra from this time interval evidence the warmest and most favorable climate conditions. After 8.0 cal. ka mosses and lichen vegetation with scare herbs typical for the modern arctic tundra dominated. German: Auf der Grundlage detaillierter Pollen- und Sporenspektren aus einem 14C-datierten Sedimentkern vom äußeren Schelf des westlichen Laptewmeeres wurden die langfristigen und hochaufgelösten Veränderungen der Vegetation in den letzten 12 cal. ka in der nordwestlichen Laptewmeer-Region rekonstruiert. Es wurden drei Hauptphasen der Entwicklung von Umwelt und Vegetation im umgebenden Hinterland erkannt. Die Zeit zwischen 12,0 und 10,3 cal. ka BP war charakterisiert durch Riedgras- und Moos-Tundra. Rasche Ausdehnung der Kraut-Tundra mit Zwergbirke und Erle begann etwa um 10,3 cal. ka und dauerte bis 8,0 cal. ka. Pollenspektren aus diesem Zeitintervall beschreiben die wärmsten und besten Klimabedingungen. Nach 8,0 cal. ka dominierte die für die heutige arktische Tundra typische Moos- und Flechtenvegetation mit wenigen Kräutern

Impacts of extreme winter warming events on litter decomposition in a sub-Arctic heathland

Arctic climate change is expected to lead to a greater frequency of extreme winter warming events. During these events, temperatures rapidly increase to well above 0 degrees C for a number of days, which can lead to snow melt at the landscape scale, loss of insulating snow cover and warming of soils. However, upon return of cold ambient temperatures, soils can freeze deeper and may experience more freeze-thaw cycles due to the absence of a buffering snow layer. Such loss of snow cover and changes in soil temperatures may be critical for litter decomposition since a stable soil microclimate during winter (facilitated by snow cover) allows activity of soil organisms. Indeed, a substantial part of fresh litter decomposition may occur in winter. However, the impacts of extreme winter warming events on soil processes such as decomposition have never before been investigated. With this study we quantify the impacts of winter warming events on fresh litter decomposition using field simulations and lab studies. Winter warming events were simulated in sub-Arctic heathland using infrared heating lamps and soil warming cables during March (typically the period of maximum snow depth) in three consecutive years of 2007, 2008, and 2009. During the winters of 2008 and 2009, simulations were also run in January (typically a period of shallow snow cover) on separate plots. The lab study included soil cores with and without fresh litter subjected to winter-warming simulations in climate chambers. Litter decomposition of common plant species was unaffected by winter warming events simulated either in the lab (litter of Betula pubescens ssp. czerepanovii), or field (litter of Vaccinium vitis-idaea, and B. pubescens ssp. czerepanovii) with the exception of Vaccinium myrtillus (a common deciduous dwarf shrub) that showed less mass loss in response to winter warming events. Soil CO2 efflux measured in the lab study was (as expected) highly responsive to winter warming events but surprisingly fresh litter decomposition was not. Most fresh litter mass loss in the lab occurred during the first 3-4 weeks (simulating the period after litter fall). In contrast to past understanding, this suggests that winter decomposition of fresh litter is almost nonexistent and observations of substantial mass loss across the cold season seen here and in other studies may result from leaching in autumn, prior to the onset of "true" winter. Further, our findings surprisingly suggest that extreme winter warming events do not affect fresh litter decomposition. Crown Copyright (c) 2009 Published by Elsevier Ltd. All rights reserved

Shieling activity in the Norse Eastern Settlement : palaeoenvironment of the 'Mountain Farm', Vatnahverfi, Greenland

Peer reviewedPostprin

Global data bases on distribution, characteristics and methane emission of natural wetlands: Documentation of archived data tape

Global digital data bases on the distribution and environmental characteristics of natural wetlands, compiled by Matthews and Fung (1987), were archived for public use. These data bases were developed to evaluate the role of wetlands in the annual emission of methane from terrestrial sources. Five global 1 deg latitude by 1 deg longitude arrays are included on the archived tape. The arrays are: (1) wetland data source, (2) wetland type, (3) fractional inundation, (4) vegetation type, and (5) soil type. The first three data bases on wetland locations were published by Matthews and Fung (1987). The last two arrays contain ancillary information about these wetland locations: vegetation type is from the data of Matthews (1983) and soil type from the data of Zobler (1986). Users should consult original publications for complete discussion of the data bases. This short paper is designed only to document the tape, and briefly explain the data sets and their initial application to estimating the annual emission of methane from natural wetlands. Included is information about array characteristics such as dimensions, read formats, record lengths, blocksizes and value ranges, and descriptions and translation tables for the individual data bases