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Extension of an Open GEOBIA Framework for Spatially Explicit Forest Stratification with Sentinel-2
(2022)
Spatially explicit information about forest cover is fundamental for operational forest management and forest monitoring. Although open-satellite-based earth observation data in a spatially high resolution (i.e., Sentinel-2, ≤10 m) can cover some information needs, spatially very high-resolution imagery (i.e., aerial imagery, ≤2 m) is needed to generate maps at a scale suitable for regional and local applications. In this study, we present the development, implementation, and evaluation of a Geographic Object-Based Image Analysis (GEOBIA) framework to stratify forests (needleleaved, broadleaved, non-forest) in Luxembourg. The framework is exclusively based on open data and free and open-source geospatial software. Although aerial imagery is used to derive image objects with a 0.05 ha minimum size, Sentinel-2 scenes of 2020 are the basis for random forest classifications in different single-date and multi-temporal feature setups. These setups are compared with each other and used to evaluate the framework against classifications based on features derived from aerial imagery. The highest overall accuracies (89.3%) have been achieved with classification on a Sentinel-2-based vegetation index time series (n = 8). Similar accuracies have been achieved with classification based on two (88.9%) or three (89.1%) Sentinel-2 scenes in the greening phase of broadleaved forests. A classification based on color infrared aerial imagery and derived texture measures only achieved an accuracy of 74.5%. The integration of the texture measures into the Sentinel-2-based classification did not improve its accuracy. Our results indicate that high resolution image objects can successfully be stratified based on lower spatial resolution Sentinel-2 single-date and multi-temporal features, and that those setups outperform classifications based on aerial imagery only. The conceptual framework of spatially high-resolution image objects enriched with features from lower resolution imagery facilitates the delivery of frequent and reliable updates due to higher spectral and temporal resolution. The framework additionally holds the potential to derive additional information layers (i.e., forest disturbance) as derivatives of the features attached to the image objects, thus providing up-to-date information on the state of observed forests.
A model-based temperature adjustment scheme for wintertime sea-ice production retrievals from MODIS
(2022)
Knowledge of the wintertime sea-ice production in Arctic polynyas is an important requirement for estimations of the dense water formation, which drives vertical mixing in the upper ocean. Satellite-based techniques incorporating relatively high resolution thermal-infrared data from MODIS in combination with atmospheric reanalysis data have proven to be a strong tool to monitor large and regularly forming polynyas and to resolve narrow thin-ice areas (i.e., leads) along the shelf-breaks and across the entire Arctic Ocean. However, the selection of the atmospheric data sets has a large influence on derived polynya characteristics due to their impact on the calculation of the heat loss to the atmosphere, which is determined by the local thin-ice thickness. In order to overcome this methodical ambiguity, we present a MODIS-assisted temperature adjustment (MATA) algorithm that yields corrections of the 2 m air temperature and hence decreases differences between the atmospheric input data sets. The adjustment algorithm is based on atmospheric model simulations. We focus on the Laptev Sea region for detailed case studies on the developed algorithm and present time series of polynya characteristics in the winter season 2019/2020. It shows that the application of the empirically derived correction decreases the difference between different utilized atmospheric products significantly from 49% to 23%. Additional filter strategies are applied that aim at increasing the capability to include leads in the quasi-daily and persistence-filtered thin-ice thickness composites. More generally, the winter of 2019/2020 features high polynya activity in the eastern Arctic and less activity in the Canadian Arctic Archipelago, presumably as a result of the particularly strong polar vortex in early 2020.
The larval stage of the European fire salamander (Salamandra salamandra) inhabits both lentic and lotic habitats. In the latter, they are constantly exposed to unidirectional water flow, which has been shown to cause downstream drift in a variety of taxa. In this study, a closed artificial creek, which allowed us to keep the water flow constant over time and, at the same time, to simulates with predefined water quantities and durations, was used to examine the individual movement patterns of marked larval fire salamanders exposed to unidirectional flow. Movements were tracked by marking the larvae with VIAlpha tags individually and by using downstream and upstream traps. Most individuals showed stationarity, while downstream drift dominated the overall movement pattern. Upstream movements were rare and occurred only on small distances of about 30 cm; downstream drift distances exceeded 10 m (until next downstream trap). The simulated flood events increased drift rates significantly, even several days after the flood simulation experiments. Drift probability increased with decreasing body size and decreasing nutritional status. Our results support the production hypothesis as an explanation for the movements of European fire salamander larvae within creeks.
Measurements of dust emissions and the modeling of dissipation dynamics and total values are related to great uncertainties. Agricultural activity, especially soil cultivation, may be an essential component to calculate and model local and regional dust dynamics and even connect to the global dust cycle. To budget total dust and to assess the impact of tillage, measurement of mobilized and transported dust is an essential but rare basis. In this study, a simple measurement concept with Modified Wilson and Cook samplers was applied for dust measurements on a small temporal and spatial scale on steep-slope vineyards in the Moselle area. Without mechanical impact, a mean horizontal flux of 0.01 g m2 min−1 was measured, while row tillage produced a mean horizontal flux of 5.92 g m2 min−1 of mobilized material and 4.18 g m2 min−1 emitted dust from site (=soil loss). Compared on this singular-event basis, emissions during tillage operations generated 99.89% of total emitted dust from the site under low mean wind velocities. The results also indicate a differing impact of specific cultivation operations, mulching, and tillage tools as well as the additional influence of environmental conditions, with highest emissions on dry soil and with additional wind impact. The dust source function is strongly associated with cultivation operations, implying highly dynamic but also regular and thus predictable and projectable emission peaks of total suspended particles. Detailed knowledge of the effects of mechanical impulses and reliable quantification of the local dust emission inventory are a basis for analysis of risk potential and choice of adequate management options.
Anpassung an den Klimawandel ist eine Zukunftsaufgabe. Auch für den Tourismussektor in der Moselregion.
Der vorliegende Bericht gibt einen Überblick zu den Chancen und Risiken, die im Rahmen des Klimawandels für den Weintourismus an der Mittelmosel entstehen. Mit Hilfe einer SWOT-Analyse wurden am Beispiel der im Projekt Mosel-AdapTiV kooperierenden Kommune Tra-ben-Trarbach exemplarisch die Auswirkungen für eine Vielzahl traditioneller Weinbauorte an der Mittelmosel untersucht.
Als touristische Destination ist die Region Mittelmosel von vielfältigen Auswirkungen des Klimawandels betroffen. Eine Verschiebung der Vegetationsperioden, Extremereignisse wie Starkregen oder Hitzeperioden werden das Leben und Wirtschaften in der Region grundlegend verändern. Diese Klimawirkfolgen treffen mit weiteren regionalökonomischen, soziokulturellen und umweltbezogenen Veränderungen zusammen. Daraus gehen Risiken und zum Teil auch Chancen für den Weintourismus und dessen Vermarktung einher. Wie wir in der Studie zeigen, sind Chancen (beispielsweise durch die Verlängerung der Sommersaison durch veränderte Mitteltemperaturen) aber häufig mit Risiken verbunden (beispielsweise für die identitätsstiftende Weinkulturlandschaft und den beliebten charakteristischen Riesling). Beide Aspekte, die Chancen sowie die Risiken zu untersuchen, ist Gegenstand der SWOT Analyse. Sie hat das Ziel, lokale und regionale Akteure des Tourismus sowie der Stadt- und Regio-nalentwicklung zu sensibilisieren und zu informieren und dazu anzuregen, geeignete Anpas-sungsstrategien zu entwickeln.
Anpassung an die Auswirkungen des Klimawandels bedeutet, sich mit den Folgen zu befassen, Risiken in verschiedenen Sektoren und Handlungsfeldern zu minimieren und sich auf veränderte klimatische Bedingungen in der Zukunft einzustellen. Im Rahmen dessen sollten kon-krete Anpassungsmaßnahmen entwickelt und implementiert werden. Dieser Bericht enthält erste Handlungsempfehlungen. Sie setzen bei der touristischen Vermarktung an, um Chancen wie verlängerte Wärmeperioden oder ein erweitertes Angebotsportfolio nutzen zu können. Zum Minimieren von Risiken empfehlen sich Ansätze wie die Sensibilisierung und Information der Akteur*innen, sowie konkrete Maßnahmen, bspw. zur Reduktion von Hitzestress. Diese Handlungsempfehlungen sollen nicht zuletzt den Akteur*innen vor Ort als Leitfaden zur Kli-mawandelanpassung im Traben-Trarbacher (Wein-)Tourismus dienen. Die Erkenntnisse dieses Berichts dienen als entsprechende Grundlage.
Dieser Bericht basiert auf einer Auswertung relevanter Literatur, der Analyse örtlicher und überregionaler Tourismuskonzepte sowie mehreren qualitativen Interviews mit Akteur*innen vor Ort. Er bildet eine Basis für die weitere Projektarbeit und soll dabei helfen, sektorenübergreifende, langfristige und ganzheitliche Anpassungsstrategien zu entwickeln.
Introduction:In patients with common variable immunodeficiency (CVID),immunological response is compromised. Knowledge about COVID‐19 in CVIDpatients is sparse. We, here, synthesize current research addressing the level ofthreat COVID‐19posestoCVIDpatientsandthebest‐known treatments.
Method:Review of 14 publications.
Results:The number of CVID patients with moderate to severe (~29%) andcritical infection courses (~10%), and the number of fatal cases (~13%), areincreased compared to the general picture of COVID‐19 infection. However,this might be an overestimate. Systematic cohort‐wide studies are lacking, andasymptomatic or mild cases among CVID patients occur that can easily remainunnoticed. Regular immunoglobulin replacement therapy was administered inalmost all patients, potentially explaining why the numbers of critical and fatalcases were not higher. In addition, the application of convalescent plasma wasdemonstrated to have positive effects.
Conclusions:COVID‐19 poses an elevated threat to CVID patients. However,only systematic studies can provide robust information on the extent of thisthreat. Regular immunoglobulin replacement therapy is beneficial to combatCOVID‐19 in CVID patients, and best treatment after infection includes theuse of convalescent plasma in addition to common medication.
Amphibian diversity in the Amazonian floating meadows: a Hanski core-satellite species system
(2021)
The Amazon catchment is the largest river basin on earth, and up to 30% of its waters flow across floodplains. In its open waters, floating plants known as floating meadows abound. They can act as vectors of dispersal for their associated fauna and, therefore, can be important for the spatial structure of communities. Here, we focus on amphibian diversity in the Amazonian floating meadows over large spatial scales. We recorded 50 amphibian species over 57 sites, covering around 7000 km along river courses. Using multi-site generalised dissimilarity modelling of zeta diversity, we tested Hanski's core-satellite hypothesis and identified the existence of two functional groups of species operating under different ecological processes in the floating meadows. ‘Core' species are associated with floating meadows, while ‘satellite' species are associated with adjacent environments, being only occasional or accidental occupants of the floating vegetation. At large scales, amphibian diversity in floating meadows is mostly determined by stochastic (i.e. random/neutral) processes, whereas at regional scales, climate and deterministic (i.e. niche-based) processes are central drivers. Compared with the turnover of ‘core' species, the turnover of ‘satellite' species increases much faster with distances and is also controlled by a wider range of climatic features. Distance is not a limiting factor for ‘core' species, suggesting that they have a stronger dispersal ability even over large distances. This is probably related to the existence of passive long-distance dispersal of individuals along rivers via vegetation rafts. In this sense, Amazonian rivers can facilitate dispersal, and this effect should be stronger for species associated with riverine habitats such as floating meadows.
Energy transition strategies in Germany have led to an expansion of energy crop cultivation in landscape, with silage maize as most valuable feedstock. The changes in the traditional cropping systems, with increasing shares of maize, raised concerns about the sustainability of agricultural feedstock production regarding threats to soil health. However, spatially explicit data about silage maize cultivation are missing; thus, implications for soil cannot be estimated in a precise way. With this study, we firstly aimed to track the fields cultivated with maize based on remote sensing data. Secondly, available soil data were target-specifically processed to determine the site-specific vulnerability of the soils for erosion and compaction. The generated, spatially-explicit data served as basis for a differentiated analysis of the development of the agricultural biogas sector, associated maize cultivation and its implications for soil health. In the study area, located in a low mountain range region in Western Germany, the number and capacity of biogas producing units increased by 25 installations and 10,163 kW from 2009 to 2016. The remote sensing-based classification approach showed that the maize cultivation area was expanded by 16% from 7305 to 8447 hectares. Thus, maize cultivation accounted for about 20% of the arable land use; however, with distinct local differences. Significant shares of about 30% of the maize cultivation was done on fields that show at least high potentials for soil erosion exceeding 25 t soil ha−1 a−1. Furthermore, about 10% of the maize cultivation was done on fields that pedogenetically show an elevated risk for soil compaction. In order to reach more sustainable cultivation systems of feedstock for anaerobic digestion, changes in cultivated crops and management strategies are urgently required, particularly against first signs of climate change. The presented approach can regionally be modified in order to develop site-adapted, sustainable bioenergy cropping systems.
Background
The morphology of anuran larvae is suggested to differ between species with tadpoles living in standing (lentic) and running (lotic) waters. To explore which character combinations within the general tadpole morphospace are associated with these habitats, we studied categorical and metric larval data of 123 (one third of which from lotic environments) Madagascan anurans.
Results
Using univariate and multivariate statistics, we found that certain combinations of fin height, body musculature and eye size prevail either in larvae from lentic or lotic environments.
Conclusion
Evidence for adaptation to lotic conditions in larvae of Madagascan anurans is presented. While lentic tadpoles typically show narrow to moderate oral discs, small to medium sized eyes, convex or moderately low fins and non-robust tail muscles, tadpoles from lotic environments typically show moderate to broad oral discs, medium to big sized eyes, low fins and a robust tail muscle.
The state-of-the-art finite element software Plaxis 3D was applied in a real-world study site of the Turaida castle mound to investigate the slope stability of the mound and understand the mechanisms triggering landslides there. During the simulation, the stability of the castle mound was analysed and the most landslide-susceptible zones of hillslopes were determined. The 3D finite-element stability analysis has significant advantages over conventional 2D limit-equilibrium methods where locations of 2D stability sections are arbitrarily selected. Two modelling scenarios of the slope stability were elaborated considering deep-seated slides in bedrock and shallow landslides in the colluvial material of slopes. The model shows that shallow slides in colluvium are more probable. In the finite-element model, slope failure occurs along the weakest zone in colluvium, similarly to the situation observed in previous landslides in the study site. The physical basis of the model allows results to be obtained very close to natural conditions and delivers valuable insight in triggering mechanisms of landslides.