Delineation of the forest-tundra ecotone using texture-based classification of satellite imagery

© 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group. The transition zone between the boreal forest and Arctic tundra, the forest-tundra ecotone (FTE), is an area of high ecological and climatological significance. Despite its importance, a globally consistent high spatial resolution mapping is lacking. Accurate mapping of the FTE requires the use of satellite remote sensing data. Here we use the Landsat Vegetation Continuous Fields (VCF) product and reference point data to derive the location and characteristics of the FTE. An image texture-based supervised classification scheme is developed based on a study area in Central Eurasia to statistically exploit the spatial patterns of the transition zone. Texture statistics for the VCF image are derived from the grey-level co-occurrence matrix (GLCM) based on which the study area is classified into forest, tundra, and FTEs. Adaptive parameterization is implemented to achieve optimal classification performance in the study area. This method is further applied to six additional study areas around the circumarctic region to test its adaptability. In all study areas, this method achieves better FTE delineation results than previously reported methods, showing better classification accuracies (average of 0.826) and more realistic and complete representation of the FTE as shown by visual examination. This shows the universal applicability of the method and it is potential to be used to achieve more detailed and accurate circumarctic mapping of the FTE, which could serve as the basis of time series analysis of FTE positions, eventually contributing to a better understanding of the inter-relations between climate change and shifts in sub-arctic vegetation.Grant no. 260400/E10 and 244557/RI, Research Council of Norwa

Strategier i forskningsveiledning? En analyse av veilederes tilbakemelding på tekst

Denne artikkelen vil belyse spørsmålet om forskningsveiledere i høyere utdanning har noen strategier for sin veiledningsvirksomhet og hva som eventuelt kjennetegner slike strategier. Utgangspunktet ligger i analyse av innledninger til en veiledningssamtale som deltakere på kurs om forskningsveiledning har skrevet som ledd i kurset. Analysekategoriene er hentet fra tidligere forskning. Artikkelen viser, illustrert gjennom sitater fra materialet, hvordan veilederne uttrykker seg innen de ulike kategoriene som kan ses som strategiske elementer. Det blir gitt eksempler pa° hvordan veiledernes bruk av kategoriene kan sammenfattes til ulike overordnede strategier for forskningsveiledning. Til slutt drøftes hvordan slike strategier kan forstås som et uttrykk for veiledernes praksisteori for forskningsveiledning og sammenhengen mellom slike praksisteorier og sentrale trekk ved kulturen i høyere utdanning

North Fennoscandian mountain forests : History, composition, disturbance dynamics and the unpredictable future

North Fennoscandian mountain forests are distributed along the Scandes Mountains between Sweden and Norway, and the low-mountain regions of northern Norway, Sweden and Finland, and the adjacent northwestern Russia. Regionally, these forests are differentiated into spruce, pine or birch dominance due to climatic differences. Variation in tree species dominance within these regions is generally caused by a combination of historical and prevailing disturbance regimes, including both chronic and episodic disturbances, their magnitude and frequency, as well as differences in edaphic conditions and topography. Because of their remoteness, slow growth and restrictions of use, these mountain forests are generally less affected by human utilization than more productive and easily utilizable forests at lower elevations and/or latitudes. As a consequence, these northern forests of Europe are often referred to as "Europe's last wilderness", even if human influence of varying intensity has been ubiquitous through historical time. Because of their naturalness, the North Fennoscandian mountain forests are of paramount importance for biodiversity conservation, monitoring of ecosystem change and for their sociocultural values. As such, they also provide unique reference areas for basic and applied research, and for developing methods of forest conservation, restoration and ecosystem-based management for the entire Fennoscandia. However, the current rapid change in climate is predicted to profoundly affect the ecology and dynamics of these forests in the future. (C) 2016 Elsevier B.V. All rights reserved.Peer reviewe

Faces of a Changing Climate: Semi-Quantitative Multi-Mycotoxin Analysis of Grain Grown in Exceptional Climatic Conditions in Norway

Recent climatological research predicts a significantly wetter climate in Southern Norway as a result of global warming. Thus, the country has already experienced unusually wet summer seasons in the last three years (2010–2012). The aim of this pilot study was to apply an existing multi-analyte LC-MS/MS method for the semi-quantitative determination of 320 fungal and bacterial metabolites in Norwegian cereal grain samples from the 2011 growing season. Such knowledge could provide important information for future survey and research programmes in Norway. The method includes all regulated and well-known mycotoxins such as aflatoxins, trichothecenes, ochratoxin A, fumonisins and zearalenone. In addition, a wide range of less studied compounds are included in the method, e.g., Alternaria toxins, ergot alkaloids and other metabolites produced by fungal species within Fusarium, Penicillium and Aspergillus. Altogether, 46 metabolites, all of fungal origin, were detected in the 76 barley, oats and wheat samples. The analyses confirmed the high prevalence and relatively high concentrations of type-A and -B trichothecenes (e.g., deoxynivalenol up to 7230 µg/kg, HT-2 toxin up to 333 µg/kg). Zearalenone was also among the major mycotoxins detected (maximum concentration 1670 µg/kg). Notably, several other Fusarium metabolites such as culmorin, 2-amino-14,16-dimethyloctadecan-3-ol and avenacein Y were co-occurring. Furthermore, the most prevalent Alternaria toxin was alternariol with a maximum concentration of 449 µg/kg. A number of Penicillium and Aspergillus metabolites were also detected in the samples, e.g., sterigmatocystin in concentrations up to 20 µg/kg

THE MORPHOMETRIC STRUCTURE OF THE LARIX GMELLINII RECRUITMENT AT THE NORTHERN LIMIT OF ITS RANGE IN THE FOREST-TUNDRA ECOTONE

The goal of the research presented herein is the investigation of the morphometric and age parameters of the recruitment of forest stands formed by Larix gmellinii, as an indicator of trends in the dynamics of the northern/upper forest boundary in the Russian Arctic, in Northern Central Siberia, in the Taimyr State Biosphere Reserve (the Ary-Mas site), and in the buffer zone of the State Biosphere Reserve “Putorana Plateau.” The morphometric parameters clearly reflect the conditions of growth and regeneration of Larix gmellinii at the northern and upper limits of its range. Both sample sites have relatively harsh conditions for growth and survival. Despite coarse soils (high gravel content) of the Putorana slopes, their significant steepness, frequent landslides and creep, the conditions for Larix gmellinii growth are better than at the Ary-Mas site. This is also reflected in the rate of regeneration. Thus, at the comparable average height of the recruitment at the forest line, its age on the Putorana Plateau is almost half of that at the Ary-Mas site (9.7 and 17.3, respectively). However, the age of the recruitment at the tree line and at the forest line on the Putorana Plateau is practically the same, while at the Ary-Mas site, the recruitment age at the tree line is 1.5 lower than at the boundary of forest. These results could indicate a trend of Larix gmellinii expansion into the ecotone over the last 20–30 yrs., especially in the mountains of the Putorana Plateau

Unsupervised Idealization of Ion Channel Recordings by Minimum Description Length:Application to Human PIEZO1-Channels

Researchers can investigate the mechanistic and molecular basis of many physiological phenomena in cells by analyzing the fundamental properties of single ion channels. These analyses entail recording single channel currents and measuring current amplitudes and transition rates between conductance states. Since most electrophysiological recordings contain noise, the data analysis can proceed by idealizing the recordings to isolate the true currents from the noise. This de-noising can be accomplished with threshold crossing algorithms and Hidden Markov Models, but such procedures generally depend on inputs and supervision by the user, thus requiring some prior knowledge of underlying processes. Channels with unknown gating and/or functional sub-states and the presence in the recording of currents from uncorrelated background channels present substantial challenges to such analyses. Here we describe and characterize an idealization algorithm based on Rissanen's Minimum Description Length (MDL) Principle. This method uses minimal assumptions and idealizes ion channel recordings without requiring a detailed user input or a priori assumptions about channel conductance and kinetics. Furthermore, we demonstrate that correlation analysis of conductance steps can resolve properties of single ion channels in recordings contaminated by signals from multiple channels. We first validated our methods on simulated data defined with a range of different signal-to-noise levels, and then showed that our algorithm can recover channel currents and their substates from recordings with multiple channels, even under conditions of high noise. We then tested the MDL algorithm on real experimental data from human PIEZO1 channels and found that our method revealed the presence of substates with alternate conductances

AEROSPACE MAPPING OF THE STATUS AND POSITION OF NORTHERN FOREST LIMIT

We study changes in the position of the northern forest limit and state of vegetation in the taiga-tundra ecotone through aerial and satellite imagery in the context of climate variability and of the projected advance of forests to the north. Our research of reference sites in Kola Peninsula and in Central Siberia has been part of PPS Arctic project of the International Polar Year. Studying the dynamics of ecotones by remote sensing is difficult due to poor display of ecotone vegetation in satellite images, and this required a range of techniques, regionally adapted and based on remotely sensed data of different spatial resolution. We characterize the newly developed techniques that enabled to identify vegetation change in recent decades: advance of forest up the slopes by 30 m in the Khibiny Mountains; advance of lichen-dwarf shrub tundra into lichen tundra in the north of Kola Peninsula; increasing stand density in sparse larch forests in the Khatanga River basin in the Taimyr Peninsula