scholarly journals Spectral characteristics of the Arctic ornithogenic tundra vegetation in Hornsund area, SW Spitsbergen

2009 ◽  
pp. 249-262 ◽  
Author(s):  
Katarzyna ZMUDCZYŃSKA
Keyword(s):  
Spectral Characteristics ◽  
The Arctic ◽  
Tundra Vegetation ◽  
Ornithogenic Tundra

scholarly journals A Photographic Record of the Upper Headwater Tributaries, Basins and Riparia of the Snake River

2011 ◽  
Vol 33 ◽  
pp. 107-113
Author(s):  
Susan Green ◽  
Dr. Michael Krop
Keyword(s):  
Global Warming ◽  
World War Ii ◽  
The Arctic ◽  
Snake River ◽  
Glacier Bay ◽  
Tundra Vegetation ◽  
The Us ◽  
Arctic Coast ◽  
Vantage Points ◽  
Bear Management

Photographic surveys have been used since the early 1940’s to document coastlines, fuel supplies and river courses. The US Navy, post world war II, flew over the Arctic coast to document possible locations for oil extraction. These very same photos are now being utilized to compare changes in tundra vegetation at the same locations today. John Muirs’ photos of Glacier Bay are a startling testament to the melted glaciers no longer visible from the same vantage point in present times. Taking photographs to monitor change may not tell the entire story behind a change in landscape. However, photos taken over a number of years from the same vantage points, can help monitor landscape changes due to habitat fragmentation, global warming, forest fire, cattle grazing and other land management issues. Photo monitoring is inexpensive, simple and can portray change to many different groups. Of course, photos taken to reveal change must start with documenting current or normal conditions. This is sometimes called baseline monitoring. The park ranger in Glacier National Park did not realize when he took his picture of the Grinnell glacier in 1911 that his photo would become an alarming baseline photo for evidence of global warming. The purpose of this project was to document the Snake River headwater basin and its riparian zones as a document in time for future reference. The original documentation included 48 images of two main headwater areas; the Shoshone and Lewis Lake areas and the Fox Park-Two Ocean Bear Management Areas near the Yellowstone Park border. Since the Shoshone-Lewis lakes are easily assessable and photo space here is limited, I have chosen to only use photos from the more remote areas.

scholarly journals Potential Arctic tundra vegetation shifts in response to changing temperature, precipitation and permafrost thaw

2016 ◽  
Vol 13 (22) ◽  
pp. 6229-6245 ◽  
Author(s):  
Henk-Jan van der Kolk ◽  
Monique M. P. D. Heijmans ◽  
Jacobus van Huissteden ◽  
Jeroen W. M. Pullens ◽  
Frank Berendse
Keyword(s):  
Climate Change ◽  
The Arctic ◽  
Soil Conditions ◽  
Climate Change Scenarios ◽  
Vegetation Shifts ◽  
Permafrost Thaw ◽  
Temperature And Precipitation ◽  
Tundra Vegetation ◽  
Tundra Ecosystem ◽  
Wide Range

Abstract. Over the past decades, vegetation and climate have changed significantly in the Arctic. Deciduous shrub cover is often assumed to expand in tundra landscapes, but more frequent abrupt permafrost thaw resulting in formation of thaw ponds could lead to vegetation shifts towards graminoid-dominated wetland. Which factors drive vegetation changes in the tundra ecosystem are still not sufficiently clear. In this study, the dynamic tundra vegetation model, NUCOM-tundra (NUtrient and COMpetition), was used to evaluate the consequences of climate change scenarios of warming and increasing precipitation for future tundra vegetation change. The model includes three plant functional types (moss, graminoids and shrubs), carbon and nitrogen cycling, water and permafrost dynamics and a simple thaw pond module. Climate scenario simulations were performed for 16 combinations of temperature and precipitation increases in five vegetation types representing a gradient from dry shrub-dominated to moist mixed and wet graminoid-dominated sites. Vegetation composition dynamics in currently mixed vegetation sites were dependent on both temperature and precipitation changes, with warming favouring shrub dominance and increased precipitation favouring graminoid abundance. Climate change simulations based on greenhouse gas emission scenarios in which temperature and precipitation increases were combined showed increases in biomass of both graminoids and shrubs, with graminoids increasing in abundance. The simulations suggest that shrub growth can be limited by very wet soil conditions and low nutrient supply, whereas graminoids have the advantage of being able to grow in a wide range of soil moisture conditions and have access to nutrients in deeper soil layers. Abrupt permafrost thaw initiating thaw pond formation led to complete domination of graminoids. However, due to increased drainage, shrubs could profit from such changes in adjacent areas. Both climate and thaw pond formation simulations suggest that a wetter tundra can be responsible for local shrub decline instead of shrub expansion.

scholarly journals What is the most efficient and effective method for long-term monitoring of alpine tundra vegetation?

2016 ◽  
Vol 2 (3) ◽  
pp. 127-141 ◽  
Author(s):  
Steven D. Mamet ◽  
Nathan Young ◽  
Kwok P. Chun ◽  
Jill F. Johnstone
Keyword(s):  
Species Richness ◽  
Relative Abundance ◽  
Rare Species ◽  
Alpine Tundra ◽  
The Arctic ◽  
Vegetation Monitoring ◽  
Tundra Vegetation ◽  
Long Term Monitoring ◽  
Term Monitoring

Nondestructive estimations of plant community characteristics are essential to vegetation monitoring programs. However, there is no universally accepted method for this purpose in the Arctic, partly because not all programs share the same logistical constraints and monitoring goals. Our aim was to determine the most efficient and effective method for long-term monitoring of alpine tundra vegetation. To achieve this, we established 12 vegetation-monitoring plots on a south-facing slope in the alpine tundra of southern Yukon Territory, Canada. Four observers assessed these plots for vascular plant species abundance employing three methods: visual cover (VC) and subplot frequency (SF) estimation and modified point-intercept (PI) (includes rare species present but not intersected by a pin). SF performed best in terms of time required per plot and sensitivity to variations in species richness. All methods were similarly poor at estimating relative abundance for rare species, but PI and VC were substantially better at high abundances. Differences among methods were larger than among observers. Our results suggest that SF is best when the monitoring focus is on rare species or species richness across extensive areas. However, when the focus is on monitoring changes in relative abundance of common species, VC or PI should be preferred.

scholarly journals Fire-induced changes in soil and vegetation in the forest-tundra of Western Siberia

2020 ◽  
Vol 223 ◽  
pp. 03001
Author(s):  
Oleg Sizov ◽  
Leya Brodt ◽  
Andrey Soromotin ◽  
Nikolay Prikhodko ◽  
Ramona Heim
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Western Siberia ◽  
The Arctic ◽  
Fire Scars ◽  
Forest Tundra ◽  
The North ◽  
Tundra Vegetation ◽  
Lichen Cover ◽  
The Face

Wildfires are one of the main factors for landscape change in tundra ecosystems. In the absence of external mechanical impacts, tundra plant communities are relatively stable, even in the face of climatic changes. In our study, lichen cover was degraded on burnt tundra sites, which increased the permafrost thaw depth from 100 to 190 cm. In old fire scars (burnt 1980 – 1990) of the forest-tundra, vegetation cover was dominated by trees and shrubs. The soil temperature on burnt forest-tundra sites was higher in comparison to conditions of the unburnt control sites and permafrost was was not found at a depth of 2-2,3m. Dynamics of the Normalized Difference Vegetation index (NDVI) from 1986-2020 reveal that immediately after fires, vegetation recovered and biomass increased due to the development of Betula nana shrubs. In old fire scars of the forest-tundra (burnt 1980-1990), a significant increase in NDVI values was evident, in contrast to the unburnt tundra vegetation where this trend was less pronounced. We conclude that "greening" in the north of Western Siberia may occur due to fire-induced transformation processes. The role of wildfires in the advance of the treeline to the north, driven by climate change and active economic development of the Arctic, will gradually increase in future.

scholarly journals Hyperspectral analysis of lithologies in the Arctic in areas with abundant lichen cover

2018 ◽  
pp. 51-55
Author(s):  
Sara Salehi
Keyword(s):  
Remote Sensing ◽  
Chemical Composition ◽  
Mineral Exploration ◽  
Spectral Characteristics ◽  
Image Data ◽  
Geological Mapping ◽  
The Arctic ◽  
Electromagnetic Spectrum ◽  
Rock Types ◽  
The Impact

Lithological mapping using remote sensing depends, in part, on the identification of rock types by their spectral characteristics. Chemical and physical properties of minerals and rocks determine their diagnostic spectral features throughout the electromagnetic spectrum. Shifts in the position and changes in the shape and depth of these features can be explained by variations in chemical composition of minerals. Detection of such variations is vital for discriminating minerals with similar chemical composition. Compared with multispectral image data, airborne or spaceborne hyperspectral imagery offers higher spectral resolution, which makes it possible to estimate the mineral composition of the rocks under study without direct contact. Arctic environments provide challenging ground for geological mapping and mineral exploration. Inaccessibility commonly complicates ground surveys, and the presence of ice, vegetation and rock-encrusting lichens hinders remote sensing surveys. This study addresses the following objectives: 1. Modelling the impact of lichen on the spectra of the rock substrate; 2. Identification of a robust lichen index for the deconvolution of lichen and rock mixtures and 3. Multiscale hyperspectral analysis of lithologies in areas with abundant lichens.

scholarly journals Towards Circumpolar Mapping of Arctic Settlements and Infrastructure Based on Sentinel-1 and Sentinel-2

2020 ◽  
Vol 12 (15) ◽  
pp. 2368 ◽  
Author(s):  
Annett Bartsch ◽  
Georg Pointner ◽  
Thomas Ingeman-Nielsen ◽  
Wenjun Lu
Keyword(s):  
Deep Learning ◽  
Satellite Data ◽  
Industrial Development ◽  
Spectral Characteristics ◽  
Added Value ◽  
The Arctic ◽  
Gradient Boosting ◽  
Spatial Coverage ◽  
The Impact ◽  
Sentinel 2

Infrastructure expands rapidly in the Arctic due to industrial development. At the same time, climate change impacts are pronounced in the Arctic. Ground temperatures are, for example, increasing as well as coastal erosion. A consistent account of the current human footprint is needed in order to evaluate the impact on the environments as well as risk for infrastructure. Identification of roads and settlements with satellite data is challenging due to the size of single features and low density of clusters. Spatial resolution and spectral characteristics of satellite data are the main issues regarding their separation. The Copernicus Sentinel-1 and -2 missions recently provided good spatial coverage and at the same time comparably high pixel spacing starting with 10 m for modes available across the entire Arctic. The purpose of this study was to assess the capabilities of both, Sentinel-1 C-band Synthetic Aperture Radar (SAR) and the Sentinel-2 multispectral information for Arctic focused mapping. Settings differ across the Arctic (historic settlements versus industrial, locations on bedrock versus tundra landscapes) and reference data are scarce and inconsistent. The type of features and data scarcity demand specific classification approaches. The machine learning approaches Gradient Boosting Machines (GBM) and deep learning (DL)-based semantic segmentation have been tested. Records for the Alaskan North Slope, Western Greenland, and Svalbard in addition to high-resolution satellite data have been used for validation and calibration. Deep learning is superior to GBM with respect to users accuracy. GBM therefore requires comprehensive postprocessing. SAR provides added value in case of GBM. VV is of benefit for road identification and HH for detection of buildings. Unfortunately, the Sentinel-1 acquisition strategy is varying across the Arctic. The majority is covered in VV+VH only. DL is of benefit for road and building detection but misses large proportions of other human-impacted areas, such as gravel pads which are typical for gas and oil fields. A combination of results from both GBM (Sentinel-1 and -2 combined) and DL (Sentinel-2; Sentinel-1 optional) is therefore suggested for circumpolar mapping.

Vertical distribution of trace gases and aerosols over the Russian Arctic in September 2020

2021 ◽  
Author(s):  
Boris D. Belan ◽  
Pavel Antokhin ◽  
Olga Antokhina ◽  
Victoriya Arshinova ◽  
Mikhail Arshinov ◽  
...  
Keyword(s):  
Bering Sea ◽  
Research University ◽  
Inorganic Compounds ◽  
Spectral Characteristics ◽  
Environmental Research ◽  
The Arctic ◽  
Russian Arctic ◽  
Max Planck ◽  
Primary Analysis ◽  
The Bering Sea

<p>In 2020, a unique experiment, which had ever been implemented either in the former USSR or in modern-day Russia, was carried out in the Russian Arctic by means of the Optik Tu-134 aircraft laboratory operated by IAO SB RAS. The airborne measurement campaign was conducted on September 4-17 over all seas and coastal regions of the Russian sector of the Arctic, including northern part of the Bering Sea.</p><p>During the flights, in situ measurements of CO, CO<sub>2</sub>, CH<sub>4</sub>, NO, NO<sub>2</sub>, SO<sub>2</sub>, O<sub>3</sub>, aerosols, and black carbon (BC) were performed. Air samples were taken to determine organic and inorganic compounds and biological material in aerosol particles. A remote sensing of the water turbidity in the upper sea layers was conducted by means of the LOZA-2 lidar that allowed a concentration of plankton to be derived there. Spectral characteristics of the water and underlying coastal surfaces were measured using a spectroradiometer.</p><p>The primary analysis of the obtained data showed that concentrations of CO, NO, NO<sub>2</sub>, SO<sub>2</sub>, O<sub>3</sub>, aerosols, and BC during the experiment were low that is typical for background regions. CO<sub>2</sub> mixing ratios in the lowest part of the troposphere above seas were lower than aloft. As compared with coastal areas, concentration of methane over all the seas of the Arctic sector and the Bering Sea was higher.</p><p>We would like to acknowledge our colleagues from the following organizations for their assistance in organizing and conducting this campaign, and in particular, Laboratoire des sciences du climat et de l'environnement and Laboratoire atmosphères, milieux, observations spatiales (France); Finnish Meteorological Institute and Institute for Atmospheric and Earth System Research, University of Helsinki (Finland); Center for Global Environmental Research at the National Institute for Environmental Studies (Japan); the National Oceanic and Atmospheric Administration, US Department of Commerce (USA); Max-Planck-Institute for Biochemistry (Germany); and University of Reading (UK).</p>

scholarly journals Long-term warming manipulations reveal complex decomposition responses across different tundra vegetation types

2021 ◽  
Author(s):  
Katrín Björnsdóttir ◽  
Isabel C Barrio ◽  
Ingibjörg Svala Jónsdóttir
Keyword(s):  
Mass Loss ◽  
Environmental Changes ◽  
Plant Litter ◽  
The Arctic ◽  
Vegetation Types ◽  
Positive Effects ◽  
Tundra Vegetation ◽  
Tea Bag Index ◽  
Induced Changes

In a rapidly warming tundra, ecosystems will undergo major environmental changes which are predicted to significantly alter below–ground processes, such as decomposition of plant litter. Making use of International Tundra Experiment sites (ITEX), established approximately two decades ago, we examined long–term impacts of warming on decomposition. We used the Tea Bag Index (TBI) methodology to measure the annual mass loss (%) of two tea types as a proxy for potential decomposition rates, across five tundra vegetation types. Direct effects of warming were assessed by comparing mass loss within and outside warming manipulations. Indirect effects of warming, such as those caused by warming–induced changes in plant community composition, were assessed through the relationship between mass loss of tea and biotic and abiotic local conditions. We found positive effects of warming on decomposition, although the responses varied between vegetation and tea types. Interestingly, we found support for the indirect influence of long–term warming on decomposition through warming–induced changes in the composition of plant communities. Our findings demonstrate the complexity in decomposition responses to warming across different vegetation types and highlight the importance of long–term legacies of warming in decomposition responses across the Arctic.

scholarly journals The Trans-Alaska Pipeline System Facilitates Shrub Establishment in Northern Alaska

ARCTIC ◽  
2018 ◽  
Vol 71 (3) ◽  
Author(s):  
Rosemary A. Dwight ◽  
David M. Cairns
Keyword(s):  
Satellite Imagery ◽  
Environmental Changes ◽  
Arctic Tundra ◽  
The Arctic ◽  
Pipeline System ◽  
Permafrost Degradation ◽  
Tundra Vegetation ◽  
Favorable Conditions ◽  
Northern Alaska ◽  
Shrub Establishment

The Arctic tundra is undergoing many environmental changes in addition to increasing temperatures: these changes include permafrost degradation and increased shrubification. Disturbances related to infrastructure can also lead to similar environmental changes. The Trans-Alaska Pipeline System (TAPS) is an example of infrastructure that has made a major imprint on the Alaskan landscape. This paper assesses changes in shrub presence along the northernmost 255 km of the TAPS. We used historical satellite imagery from before construction of the TAPS in 1974 and contemporary satellite imagery from 2010 to 2016 to examine changes in shrub presence over time. We found a 51.8% increase in shrub presence adjacent to the pipeline compared to 2.6% in control areas. Additionally, shrub presence has increased significantly more in areas where the pipeline is buried, indicating that the disturbances linked to pipeline burial have likely created favorable conditions for shrub colonization. These results are important for predicting potential responses of tundra vegetation to disturbance, which will be crucial to forecasting the future of Arctic tundra vegetation.

Seeing the tundra for the plants, on the eco-spiritual wholeness of arctic vegetation

2021 ◽  
pp. 003776862110436
Author(s):  
Sveta Yamin-Pasternak ◽  
Igor Pasternak
Keyword(s):  
Vegetation Cover ◽  
Field Research ◽  
Arctic Tundra ◽  
Social Contexts ◽  
The Arctic ◽  
Arctic Vegetation ◽  
Plant Interaction ◽  
Tundra Vegetation ◽  
Spiritual Wholeness ◽  
Human World

Drawing on ethnographic field research in Chukotka, Russia, this article explores ideas and practices connected with the Arctic tundra vegetation that speak to its place in Chukchi spirituality and cultural milieu. The ethnographic focus is on a Chukchi remembrance ceremony with other social contexts of human–plant interaction offered as comparative examples. Contributing novel insight for the considerations of sentient landscapes and ceremonial engagements with plants, the article turns to the Chukchi eco-spiritual relationships in the beyond-the-human world. It suggests that the vegetation cover is not merely an assemblage of fungi and plants, but an organismal membrane through which the tundra communicates and acts, while also facilitating integrations between the human and beyond-the-human worlds.

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