TY - JOUR A1 - Foster, William J. A1 - Heindel, Katrin A1 - Richoz, Sylvain A1 - Gliwa, Jana A1 - Lehrmann, Daniel J. A1 - Baud, Aymon A1 - Kolar-Jurkovsek, Tea A1 - Aljinovic, Dunja A1 - Jurkovsek, Bogdan A1 - Korn, Dieter A1 - Martindale, Rowan C. A1 - Peckmann, Jörn T1 - Suppressed competitive exclusion enabled the proliferation of Permian/Triassic boundary microbialites JF - The Depositional Record : the open access journal of the International Association of Sedimentologists N2 - During the earliest Triassic microbial mats flourished in the photic zones of marginal seas, generating widespread microbialites. It has been suggested that anoxic conditions in shallow marine environments, linked to the end-Permian mass extinction, limited mat-inhibiting metazoans allowing for this microbialite expansion. The presence of a diverse suite of proxies indicating oxygenated shallow sea-water conditions (metazoan fossils, biomarkers and redox proxies) from microbialite successions have, however, challenged the inference of anoxic conditions. Here, the distribution and faunal composition of Griesbachian microbialites from China, Iran, Turkey, Armenia, Slovenia and Hungary are investigated to determine the factors that allowed microbialite-forming microbial mats to flourish following the end-Permian crisis. The results presented here show that Neotethyan microbial buildups record a unique faunal association due to the presence of keratose sponges, while the Palaeotethyan buildups have a higher proportion of molluscs and the foraminifera Earlandia. The distribution of the faunal components within the microbial fabrics suggests that, except for the keratose sponges and some microconchids, most of the metazoans were transported into the microbial framework via wave currents. The presence of both microbialites and metazoan associations were limited to oxygenated settings, suggesting that a factor other than anoxia resulted in a relaxation of ecological constraints following the mass extinction event. It is inferred that the end-Permian mass extinction event decreased the diversity and abundance of metazoans to the point of significantly reducing competition, allowing photosynthesis-based microbial mats to flourish in shallow water settings and resulting in the formation of widespread microbialites. KW - Competitive exclusion KW - Permian KW - Triassic KW - mass extinction KW - microbialites KW - palaeoecology Y1 - 2019 U6 - https://doi.org/10.1002/dep2.97 SN - 2055-4877 VL - 6 IS - 1 SP - 62 EP - 74 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Bielcik, Milos A1 - Aguilar-Trigueros, Carlos A. A1 - Lakovic, Milica A1 - Jeltsch, Florian A1 - Rillig, Matthias C. T1 - The role of active movement in fungal ecology and community assembly JF - Movement Ecology N2 - Movement ecology aims to provide common terminology and an integrative framework of movement research across all groups of organisms. Yet such work has focused on unitary organisms so far, and thus the important group of filamentous fungi has not been considered in this context. With the exception of spore dispersal, movement in filamentous fungi has not been integrated into the movement ecology field. At the same time, the field of fungal ecology has been advancing research on topics like informed growth, mycelial translocations, or fungal highways using its own terminology and frameworks, overlooking the theoretical developments within movement ecology. We provide a conceptual and terminological framework for interdisciplinary collaboration between these two disciplines, and show how both can benefit from closer links: We show how placing the knowledge from fungal biology and ecology into the framework of movement ecology can inspire both theoretical and empirical developments, eventually leading towards a better understanding of fungal ecology and community assembly. Conversely, by a greater focus on movement specificities of filamentous fungi, movement ecology stands to benefit from the challenge to evolve its concepts and terminology towards even greater universality. We show how our concept can be applied for other modular organisms (such as clonal plants and slime molds), and how this can lead towards comparative studies with the relationship between organismal movement and ecosystems in the focus. KW - Filamentous fungi KW - Microbial community KW - Active movement KW - Modular organisms KW - Interference competition KW - Fungal space searching algorithms KW - Fungal foraging KW - Fungal highways KW - Clonal plants KW - Slime molds Y1 - 2019 U6 - https://doi.org/10.1186/s40462-019-0180-6 SN - 2051-3933 VL - 7 IS - 1 PB - BMC CY - London ER - TY - JOUR A1 - Costa Tomaz de Souza, Arthur A1 - Ayzel, Georgy A1 - Heistermann, Maik T1 - Quantifying the location error of precipitation nowcasts JF - Advances in meteorology N2 - In precipitation nowcasting, it is common to track the motion of precipitation in a sequence of weather radar images and to extrapolate this motion into the future. The total error of such a prediction consists of an error in the predicted location of a precipitation feature and an error in the change of precipitation intensity over lead time. So far, verification measures did not allow isolating the extent of location errors, making it difficult to specifically improve nowcast models with regard to location prediction. In this paper, we introduce a framework to directly quantify the location error. To that end, we detect and track scale-invariant precipitation features (corners) in radar images. We then consider these observed tracks as the true reference in order to evaluate the performance (or, inversely, the error) of any model that aims to predict the future location of a precipitation feature. Hence, the location error of a forecast at any lead time Delta t ahead of the forecast time t corresponds to the Euclidean distance between the observed and the predicted feature locations at t + Delta t. Based on this framework, we carried out a benchmarking case study using one year worth of weather radar composites of the German Weather Service. We evaluated the performance of four extrapolation models, two of which are based on the linear extrapolation of corner motion from t - 1 to t (LK-Lin1) and t - 4 to t (LK-Lin4) and the other two are based on the Dense Inverse Search (DIS) method: motion vectors obtained from DIS are used to predict feature locations by linear (DIS-Lin1) and Semi-Lagrangian extrapolation (DIS-Rot1). Of those four models, DIS-Lin1 and LK-Lin4 turned out to be the most skillful with regard to the prediction of feature location, while we also found that the model skill dramatically depends on the sinuosity of the observed tracks. The dataset of 376,125 detected feature tracks in 2016 is openly available to foster the improvement of location prediction in extrapolation-based nowcasting models. KW - inuosity Y1 - 2020 U6 - https://doi.org/10.1155/2020/8841913 SN - 1687-9309 SN - 1687-9317 VL - 2020 PB - Hindawi CY - London ER - TY - JOUR A1 - Oguntunde, Philip G. A1 - Abiodun, Babatunde Joseph A1 - Lischeid, Gunnar A1 - Abatan, Abayomi A. T1 - Droughts projection over the Niger and Volta River basins of West Africa at specific global warming levels JF - International Journal of Climatology N2 - This study investigates possible impacts of four global warming levels (GWLs: GWL1.5, GWL2.0, GWL2.5, and GWL3.0) on drought characteristics over Niger River basin (NRB) and Volta River basin (VRB). Two drought indices-Standardized Precipitation Index (SPI) and Standardized Precipitation-Evapotranspiration Index (SPEI)-were employed in characterizing droughts in 20 multi-model simulation outputs from the Coordinated Regional Climate Downscaling Experiment (CORDEX). The performance of the simulation in reproducing basic hydro-climatological features and severe drought characteristics (i.e., magnitude and frequency) in the basins were evaluated. The projected changes in the future drought frequency were quantified and compared under the four GWLs for two climate forcing scenarios (RCP8.5 and RCP4.5). The regional climate model (RCM) ensemble gives a realistic simulation of historical hydro-climatological variables needed to calculate the drought indices. With SPEI, the simulation ensemble projects an increase in the magnitude and frequency of severe droughts over both basins (NRB and VRB) at all GWLs, but the increase, which grows with the GWLs, is higher over NRB than over VRB. More than 75% of the simulations agree on the projected increase at GWL1.5 and all simulations agree on the increase at higher GWLs. With SPI, the projected changes in severe drought is weaker and the magnitude remains the same at all GWLs, suggesting that SPI projection may underestimate impacts of the GWLs on the intensity and severity of future drought. The results of this study have application in mitigating impact of global warming on future drought risk over the regional water systems. KW - climate change KW - drought index KW - global warming levels KW - river basins KW - West Africa KW - CORDEX data Y1 - 2019 VL - 40 IS - 13 PB - John Wiley & Sons, Inc. CY - New Jersey ER - TY - JOUR A1 - Marcisz, Katarzyna A1 - Jassey, Vincent E. J. A1 - Kosakyan, Anush A1 - Krashevska, Valentyna A1 - Lahr, Daniel J. G. A1 - Lara, Enrique A1 - Lamentowicz, Lukasz A1 - Lamentowicz, Mariusz A1 - Macumber, Andrew A1 - Mazei, Yuri A1 - Mitchell, Edward A. D. A1 - Nasser, Nawaf A. A1 - Patterson, R. Timothy A1 - Roe, Helen M. A1 - Singer, David A1 - Tsyganov, Andrey N. A1 - Fournier, Bertrand T1 - Testate amoeba functional traits and their use in paleoecology JF - Frontiers in Ecology and Evolution N2 - This review provides a synthesis of current knowledge on the morphological and functional traits of testate amoebae, a polyphyletic group of protists commonly used as proxies of past hydrological changes in paleoecological investigations from peatland, lake sediment and soil archives. A trait-based approach to understanding testate amoebae ecology and paleoecology has gained in popularity in recent years, with research showing that morphological characteristics provide complementary information to the commonly used environmental inferences based on testate amoeba (morpho-)species data. We provide a broad overview of testate amoeba morphological and functional traits and trait-environment relationships in the context of ecology, evolution, genetics, biogeography, and paleoecology. As examples we report upon previous ecological and paleoecological studies that used trait-based approaches, and describe key testate amoebae traits that can be used to improve the interpretation of environmental studies. We also highlight knowledge gaps and speculate on potential future directions for the application of trait-based approaches in testate amoeba research. KW - protists KW - functional traits KW - morphological traits KW - ecology KW - peatlands KW - lakes KW - soils KW - trait-based approaches Y1 - 2020 U6 - https://doi.org/10.3389/fevo.2020.575966 SN - 2296-701X VL - 8 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Zingraff-Hamed, Aude A1 - Hüesker, Frank A1 - Lupp, Gerd A1 - Begg, Chloe A1 - Huang, Josh A1 - Oen, Amy M. P. A1 - Vojinović, Zoran A1 - Kuhlicke, Christian A1 - Pauleit, Stephan T1 - Stakeholder mapping to co-create nature-based solutions BT - who is on board? JF - Sustainability N2 - Nature-based solutions (NBS) are inspired and supported by nature but designed by humans. Historically, governmental stakeholders have aimed to control nature using a top-down approach; more recently, environmental governance has shifted to collaborative planning. Polycentric governance and co-creation procedures, which include a large spectrum of stakeholders, are assumed to be more effective in the management of public goods than traditional approaches. In this context, NBS projects should benefit from strong collaborative governance models, and the European Union is facilitating and encouraging such models. While some theoretical approaches exist, setting-up the NBS co-creation process (namely co-design and co-implementation) currently relies mostly on self-organized stakeholders rather than on strategic decisions. As such, systematic methods to identify relevant stakeholders seem to be crucial to enable higher planning efficiency, reduce bottlenecks and time needed for planning, designing, and implementing NBS. In this context, this contribution is based on the analysis of 16 NBS and 359 stakeholders. Real-life constellations are compared to theoretical typologies, and a systematic stakeholder mapping method to support co-creation is presented. Rather than making one-fit-all statements about the "right" stakeholders, the contribution provides insights for those "in charge" to strategically consider who might be involved at each stage of the NBS project. KW - ecosystem-based KW - natural hazard mitigation KW - participative planning KW - co-design KW - polycentric governance KW - living labs KW - societal resilience KW - sustainable development goals Y1 - 2020 U6 - https://doi.org/10.3390/su12208625 SN - 2071-1050 VL - 12 IS - 20 PB - MDPI CY - Basel ER - TY - JOUR A1 - de Brito, Mariana Madruga A1 - Kuhlicke, Christian A1 - Marx, Andreas T1 - Near-real-time drought impact assessment BT - a text mining approach on the 2018/19 drought in Germany JF - Environmental research letters N2 - Contemporary drought impact assessments have been constrained due to data availability, leading to an incomplete representation of impact trends. To address this, we present a novel method for the comprehensive and near-real-time monitoring of drought socio-economic impacts based on media reports. We tested its application using the case of the exceptional 2018/19 German drought. By employing text mining techniques, 4839 impact statements were identified, relating to livestock, agriculture, forestry, fires, recreation, energy and transport sectors. An accuracy of 95.6% was obtained for their automatic classification. Furthermore, high levels of performance in terms of spatial and temporal precision were found when validating our results against independent data (e.g. soil moisture, average precipitation, population interest in droughts, crop yield and forest fire statistics). The findings highlight the applicability of media data for rapidly and accurately monitoring the propagation of drought consequences over time and space. We anticipate our method to be used as a starting point for an impact-based early warning system. KW - drought impacts KW - Germany KW - text analytics KW - newspaper KW - validation Y1 - 2020 U6 - https://doi.org/10.1088/1748-9326/aba4ca SN - 1748-9326 VL - 15 IS - 10 PB - IOP Publ. CY - Bristol ER - TY - JOUR A1 - Zoll, Felix A1 - Diehl, Katharina A1 - Siebert, Rosemarie T1 - Integrating sustainability goals in innovation processes BT - applying a decision support tool in a dual-purpose chicken case study JF - Sustainability N2 - The innovative dual-purpose chicken approach aims at contributing to the transition towards sustainable poultry production by avoiding the culling of male chickens. To successfully integrate sustainability aspects into innovation, goal congruency among actors and clearly communicating the added value within the actor network and to consumers is needed. The challenge of identifying common sustainability goals calls for decision support tools. The objectives of our research were to investigate whether the tool could assist in improving communication and marketing with respect to sustainability and optimizing the value chain organization. Three actor groups participated in the tool application, in which quantitative and qualitative data were collected. The results showed that there were manifold sustainability goals within the innovation network, but only some goals overlapped, and the perception of their implementation also diverged. While easily marketable goals such as ‘animal welfare’ were perceived as being largely implemented, economic goals were prioritized less often, and the implementation was perceived as being rather low. By visualizing congruencies and differences in the goals, the tool helped identify fields of action, such as improved information flows and prompted thinking processes. We conclude that the tool is useful for managing complex decision processes with several actors involved. KW - value-based sustainability assessment KW - stakeholder participation KW - niche level KW - culling of male chickens KW - mixed methods Y1 - 2019 U6 - https://doi.org/10.3390/su11143761 SN - 2071-1050 VL - 11 IS - 14 PB - MDPI CY - Basel ER - TY - JOUR A1 - Hudson, Paul A1 - Hagedoorn, Liselotte A1 - Bubeck, Philip T1 - Potential linkages between social capital, flood risk perceptions, and self-efficacy JF - International journal of disaster risk science N2 - A growing focus is being placed on both individuals and communities to adapt to flooding as part of the Sendai Framework for Disaster Risk Reduction 2015-2030. Adaptation to flooding requires sufficient social capital (linkages between members of society), risk perceptions (understanding of risk), and self-efficacy (self-perceived ability to limit disaster impacts) to be effective. However, there is limited understanding of how social capital, risk perceptions, and self-efficacy interact. We seek to explore how social capital interacts with variables known to increase the likelihood of successful adaptation. To study these linkages we analyze survey data of 1010 respondents across two communities in Thua Tien-Hue Province in central Vietnam, using ordered probit models. We find positive correlations between social capital, risk perceptions, and self-efficacy overall. This is a partly contrary finding to what was found in previous studies linking these concepts in Europe, which may be a result from the difference in risk context. The absence of an overall negative exchange between these factors has positive implications for proactive flood risk adaptation. KW - flood risk KW - protection motivation theory KW - risk perceptions KW - social KW - capital KW - self-efficacy KW - Vietnam Y1 - 2020 U6 - https://doi.org/10.1007/s13753-020-00259-w SN - 2095-0055 SN - 2192-6395 VL - 11 IS - 3 SP - 251 EP - 262 PB - Springer CY - Berlin ER - TY - JOUR A1 - Tötzke, Christian A1 - Cermak, Jan A1 - Nadezhdina, Nadezhda A1 - Tributsch, Helmut T1 - Electrochemical in-situ studies of solar mediated oxygen transport and turnover dynamics in a tree trunk of Tilia cordata JF - iForest - Biogeosciences and Forestry N2 - Platinum electrodes were implanted into the xylem of a lime tree (Tilia cordata) stem and solar- induced electrochemical potential differences of up to 120 mV were measured during the vegetative period and up to 30 mV in winter. The time dependent curves were found to be delayed with respect to solar radiation, sap flow activity, temperature and vapor pressure deficit. A general equation for the potential difference was derived and simplified by analyzing the effect of temperature and tensile strength. The potential determining influence of oxygen concentration on the respective location of the platinum electrode was identified as the principal phenomenon measured. A systematic analysis and investigation of the observed periodic oxygen concentration signals promises new information on sap flow, oxygen diffusion through tree tissues and on oxygen consumption related to the energy turnover in tree tissues. KW - Tree Stems KW - Oxygen Transport KW - Xylem KW - Sap Flow KW - Tree Metabolism KW - Electrical Potential Y1 - 2017 U6 - https://doi.org/10.3832/ifor1681-010 SN - 1971-7458 VL - 10 IS - 2 SP - 355 EP - 361 PB - SISEF - The Italian Society of Silviculture and Forest Ecology CY - Potenza ER - TY - JOUR A1 - Vogel, Johannes A1 - Paton, Eva Nora A1 - Aich, Valentin T1 - Seasonal ecosystem vulnerability to climatic anomalies in the Mediterranean JF - Biogeosciences N2 - Mediterranean ecosystems are particularly vulnerable to climate change and the associated increase in climate anomalies. This study investigates extreme ecosystem responses evoked by climatic drivers in the Mediterranean Basin for the time span 1999–2019 with a specific focus on seasonal variations as the seasonal timing of climatic anomalies is considered essential for impact and vulnerability assessment. A bivariate vulnerability analysis is performed for each month of the year to quantify which combinations of the drivers temperature (obtained from ERA5-Land) and soil moisture (obtained from ESA CCI and ERA5-Land) lead to extreme reductions in ecosystem productivity using the fraction of absorbed photosynthetically active radiation (FAPAR; obtained from the Copernicus Global Land Service) as a proxy. The bivariate analysis clearly showed that, in many cases, it is not just one but a combination of both drivers that causes ecosystem vulnerability. The overall pattern shows that Mediterranean ecosystems are prone to three soil moisture regimes during the yearly cycle: they are vulnerable to hot and dry conditions from May to July, to cold and dry conditions from August to October, and to cold conditions from November to April, illustrating the shift from a soil-moisture-limited regime in summer to an energy-limited regime in winter. In late spring, a month with significant vulnerability to hot conditions only often precedes the next stage of vulnerability to both hot and dry conditions, suggesting that high temperatures lead to critically low soil moisture levels with a certain time lag. In the eastern Mediterranean, the period of vulnerability to hot and dry conditions within the year is much longer than in the western Mediterranean. Our results show that it is crucial to account for both spatial and temporal variability to adequately assess ecosystem vulnerability. The seasonal vulnerability approach presented in this study helps to provide detailed insights regarding the specific phenological stage of the year in which ecosystem vulnerability to a certain climatic condition occurs. How to cite. Vogel, J., Paton, E., and Aich, V.: Seasonal ecosystem vulnerability to climatic anomalies in the Mediterranean, Biogeosciences, 18, 5903–5927, https://doi.org/10.5194/bg-18-5903-2021, 2021. Y1 - 2021 U6 - https://doi.org/10.5194/bg-18-5903-2021 SN - 1726-4189 VL - 18 SP - 5903 EP - 5927 PB - Copernicus CY - Göttingen ET - 22 ER - TY - JOUR A1 - Bürger, Gerd T1 - A seamless filter for daily to seasonal forecasts, with applications to Iran and Brazil JF - Quarterly Journal of the Royal Meteorological Society N2 - A digital filter is introduced which treats the problem of predictability versus time averaging in a continuous, seamless manner. This seamless filter (SF) is characterized by a unique smoothing rule that determines the strength of smoothing in dependence on lead time. The rule needs to be specified beforehand, either by expert knowledge or by user demand. As a result, skill curves are obtained that allow a predictability assessment across a whole range of time-scales, from daily to seasonal, in a uniform manner. The SF is applied to downscaled SEAS5 ensemble forecasts for two focus regions in or near the tropical belt, the river basins of the Karun in Iran and the Sao Francisco in Brazil. Both are characterized by strong seasonality and semi-aridity, so that predictability across various time-scales is in high demand. Among other things, it is found that from the start of the water year (autumn), areal precipitation is predictable with good skill for the Karun basin two and a half months ahead; for the Sao Francisco it is only one month, longer-term prediction skill is just above the critical level. KW - climate drift KW - ensemble prediction KW - seamless prediction KW - seasonal forecast skill Y1 - 2019 VL - 146 IS - 726 PB - WILEY-VCH CY - Weinheim ER - TY - JOUR A1 - Hodgkins, Suzanne B. A1 - Richardson, Curtis J. A1 - Dommain, Rene A1 - Wang, Hongjun A1 - Glaser, Paul H. A1 - Verbeke, Brittany A1 - Winkler, B. Rose A1 - Cobb, Alexander R. A1 - Rich, Virginia I. A1 - Missilmani, Malak A1 - Flanagan, Neal A1 - Ho, Mengchi A1 - Hoyt, Alison M. A1 - Harvey, Charles F. A1 - Vining, S. Rose A1 - Hough, Moira A. A1 - Moore, Tim R. A1 - Richard, Pierre J. H. A1 - De la Cruz, Florentino B. A1 - Toufaily, Joumana A1 - Hamdan, Rasha A1 - Cooper, William T. A1 - Chanton, Jeffrey P. T1 - Tropical peatland carbon storage linked to global latitudinal trends in peat recalcitrance JF - Nature Communications N2 - Peatlands represent large terrestrial carbon banks. Given that most peat accumulates in boreal regions, where low temperatures and water saturation preserve organic matter, the existence of peat in (sub)tropical regions remains enigmatic. Here we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Near-surface low-latitude peat has lower carbohydrate and greater aromatic content than near-surface high-latitude peat, creating a reduced oxidation state and resulting recalcitrance. This recalcitrance allows peat to persist in the (sub)tropics despite warm temperatures. Because we observed similar declines in carbohydrate content with depth in high-latitude peat, our data explain recent field-scale deep peat warming experiments in which catotelm (deeper) peat remained stable despite temperature increases up to 9 degrees C. We suggest that high-latitude deep peat reservoirs may be stabilized in the face of climate change by their ultimately lower carbohydrate and higher aromatic composition, similar to tropical peats. Y1 - 2018 U6 - https://doi.org/10.1038/s41467-018-06050-2 SN - 2041-1723 VL - 9 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Graf, Lukas A1 - Moreno-de-las-Heras, Mariano A1 - Ruiz, Maurici A1 - Calsamiglia, Aleix A1 - García-Comendador, Julián A1 - Fortesa, Josep A1 - López-Tarazón, José A. A1 - Estrany, Joan T1 - Accuracy assessment of digital terrain model dataset sources for hydrogeomorphological modelling in small mediterranean catchments JF - Remote sensing N2 - Digital terrain models (DTMs) are a fundamental source of information in Earth sciences. DTM-based studies, however, can contain remarkable biases if limitations and inaccuracies in these models are disregarded. In this work, four freely available datasets, including Shuttle Radar Topography Mission C-Band Synthetic Aperture Radar (SRTM C-SAR V3 DEM), Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Map (ASTER GDEM V2), and two nationwide airborne light detection and ranging (LiDAR)-derived DTMs (at 5-m and 1-m spatial resolution, respectively) were analysed in three geomorphologically contrasting, small (3–5 km2) catchments located in Mediterranean landscapes under intensive human influence (Mallorca Island, Spain). Vertical accuracy as well as the influence of each dataset’s characteristics on hydrological and geomorphological modelling applicability were assessed by using ground-truth data, classic geometric and morphometric parameters, and a recently proposed index of sediment connectivity. Overall vertical accuracy—expressed as the root mean squared error (RMSE) and normalised median deviation (NMAD)—revealed the highest accuracy for the 1-m (RMSE = 1.55 m; NMAD = 0.44 m) and 5-m LiDAR DTMs (RMSE = 1.73 m; NMAD = 0.84 m). Vertical accuracy of the SRTM data was lower (RMSE = 6.98 m; NMAD = 5.27 m), but considerably higher than for the ASTER data (RMSE = 16.10 m; NMAD = 11.23 m). All datasets were affected by systematic distortions. Propagation of these errors and coarse horizontal resolution caused negative impacts on flow routing, stream network, and catchment delineation, and to a lower extent, on the distribution of slope values. These limitations should be carefully considered when applying DTMs for catchment hydrogeomorphological modelling. KW - digital terrain models KW - DTM vertical accuracy KW - DTM comparison KW - hydrogeomorphological modelling KW - Mediterranean catchments Y1 - 2018 U6 - https://doi.org/10.3390/rs10122014 SN - 2072-4292 VL - 10 IS - 12 PB - MDPI CY - Basel ER - TY - JOUR A1 - Skinner, Christopher J. A1 - Coulthard, Tom J. A1 - Schwanghart, Wolfgang A1 - Van De Wiel, Marco J. A1 - Hancock, Greg T1 - Global sensitivity analysis of parameter uncertainty in landscape evolution models JF - Geoscientific model development : an interactive open access journal of the European Geosciences Union N2 - The evaluation and verification of landscape evolution models (LEMs) has long been limited by a lack of suitable observational data and statistical measures which can fully capture the complexity of landscape changes. This lack of data limits the use of objective function based evaluation prolific in other modelling fields, and restricts the application of sensitivity analyses in the models and the consequent assessment of model uncertainties. To overcome this deficiency, a novel model function approach has been developed, with each model function representing an aspect of model behaviour, which allows for the application of sensitivity analyses. The model function approach is used to assess the relative sensitivity of the CAESAR-Lisflood LEM to a set of model parameters by applying the Morris method sensitivity analysis for two contrasting catchments. The test revealed that the model was most sensitive to the choice of the sediment transport formula for both catchments, and that each parameter influenced model behaviours differently, with model functions relating to internal geomorphic changes responding in a different way to those relating to the sediment yields from the catchment outlet. The model functions proved useful for providing a way of evaluating the sensitivity of LEMs in the absence of data and methods for an objective function approach. Y1 - 2018 U6 - https://doi.org/10.5194/gmd-11-4873-2018 SN - 1991-959X SN - 1991-9603 VL - 11 IS - 12 SP - 4873 EP - 4888 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Ayzel, Georgy A1 - Izhitskiy, Alexander T1 - Climate Change Impact Assessment on Freshwater Inflow into the Small Aral Sea JF - Water N2 - During the last few decades, the rapid separation of the Small Aral Sea from the isolated basin has changed its hydrological and ecological conditions tremendously. In the present study, we developed and validated the hybrid model for the Syr Darya River basin based on a combination of state-of-the-art hydrological and machine learning models. Climate change impact on freshwater inflow into the Small Aral Sea for the projection period 2007-2099 has been quantified based on the developed hybrid model and bias corrected and downscaled meteorological projections simulated by four General Circulation Models (GCM) for each of three Representative Concentration Pathway scenarios (RCP). The developed hybrid model reliably simulates freshwater inflow for the historical period with a Nash-Sutcliffe efficiency of 0.72 and a Kling-Gupta efficiency of 0.77. Results of the climate change impact assessment showed that the freshwater inflow projections produced by different GCMs are misleading by providing contradictory results for the projection period. However, we identified that the relative runoff changes are expected to be more pronounced in the case of more aggressive RCP scenarios. The simulated projections of freshwater inflow provide a basis for further assessment of climate change impacts on hydrological and ecological conditions of the Small Aral Sea in the 21st Century. KW - Small Aral Sea KW - hydrology KW - climate change KW - modeling KW - machine learning Y1 - 2019 U6 - https://doi.org/10.3390/w11112377 SN - 2073-4441 VL - 11 IS - 11 PB - MDPI CY - Basel ER - TY - JOUR A1 - Marrucci, Monica A1 - Zeilinger, Gerold A1 - Ribolini, Adriano A1 - Schwanghart, Wolfgang T1 - Origin of Knickpoints in an Alpine Context Subject to Different Perturbing Factors, Stura Valley, Maritime Alps (North-Western Italy) JF - Geosciences N2 - Natural catchments are likely to show the existence of knickpoints in their river networks. The origin and genesis of the knickpoints can be manifold, considering that the present morphology is the result of the interactions of different factors such as tectonic movements, quaternary glaciations, river captures, variable lithology, and base-level changes. We analyzed the longitudinal profiles of the river channels in the Stura di Demonte Valley (Maritime Alps) to identify the knickpoints of such an alpine setting and to characterize their origins. The distribution and the geometry of stream profiles were used to identify the possible causes of the changes in stream gradients and to define zones with genetically linked knickpoints. Knickpoints are key geomorphological features for reconstructing the evolution of fluvial dissected basins, when the different perturbing factors affecting the ideally graded fluvial system have been detected. This study shows that even in a regionally small area, perturbations of river profiles are caused by multiple factors. Thus, attributing (automatically)-extracted knickpoints solely to one factor, can potentially lead to incomplete interpretations of catchment evolution. KW - knickpoint KW - river longitudinal profile KW - Maritime Alps Y1 - 2018 U6 - https://doi.org/10.3390/geosciences8120443 SN - 2076-3263 VL - 8 IS - 12 PB - MDPI CY - Basel ER - TY - JOUR A1 - Bormann, Helge A1 - de Brito, Mariana Madruga A1 - Charchousi, Despoina A1 - Chatzistratis, Dimitris A1 - David, Amrei A1 - Grosser, Paula Farina A1 - Kebschull, Jenny A1 - Konis, Alexandros A1 - Koutalakis, Paschalis A1 - Korali, Alkistis A1 - Krauzig, Naomi A1 - Meier, Jessica A1 - Meliadou, Varvara A1 - Meinhardt, Markus A1 - Munnelly, Kieran A1 - Stephan, Christiane A1 - de Vos, Leon Frederik A1 - Dietrich, Jörg A1 - Tzoraki, Ourania T1 - Impact of Hydrological Modellers’ Decisions and Attitude on the Performance of a Calibrated Conceptual Catchment Model BT - Results from a ‘Modelling Contest’ JF - Hydrology N2 - In this study, 17 hydrologists with different experience in hydrological modelling applied the same conceptual catchment model (HBV) to a Greek catchment, using identical data and model code. Calibration was performed manually. Subsequently, the modellers were asked for their experience, their calibration strategy, and whether they enjoyed the exercise. The exercise revealed that there is considerable modellers’ uncertainty even among the experienced modellers. It seemed to be equally important whether the modellers followed a good calibration strategy, and whether they enjoyed modelling. The exercise confirmed previous studies about the benefit of model ensembles: Different combinations of the simulation results (median, mean) outperformed the individual model simulations, while filtering the simulations even improved the quality of the model ensembles. Modellers’ experience, decisions, and attitude, therefore, have an impact on the hydrological model application and should be considered as part of hydrological modelling uncertainty. Y1 - 2018 U6 - https://doi.org/10.3390/hydrology5040064 SN - 2306-5338 VL - 5 IS - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Vogel, Johannes A1 - Rivoire, Pauline A1 - Deidda, Cristina A1 - Rahimi, Leila A1 - Sauter, Christoph A. A1 - Tschumi, Elisabeth A1 - van der Wiel, Karin A1 - Zhang, Tianyi A1 - Zscheischler, Jakob T1 - Identifying meteorological drivers of extreme impacts BT - an application to simulated crop yields JF - Earth System Dynamics N2 - Compound weather events may lead to extreme impacts that can affect many aspects of society including agriculture. Identifying the underlying mechanisms that cause extreme impacts, such as crop failure, is of crucial importance to improve their understanding and forecasting. In this study, we investigate whether key meteorological drivers of extreme impacts can be identified using the least absolute shrinkage and selection operator (LASSO) in a model environment, a method that allows for automated variable selection and is able to handle collinearity between variables. As an example of an extreme impact, we investigate crop failure using annual wheat yield as simulated by the Agricultural Production Systems sIMulator (APSIM) crop model driven by 1600 years of daily weather data from a global climate model (EC-Earth) under present-day conditions for the Northern Hemisphere. We then apply LASSO logistic regression to determine which weather conditions during the growing season lead to crop failure. We obtain good model performance in central Europe and the eastern half of the United States, while crop failure years in regions in Asia and the western half of the United States are less accurately predicted. Model performance correlates strongly with annual mean and variability of crop yields; that is, model performance is highest in regions with relatively large annual crop yield mean and variability. Overall, for nearly all grid points, the inclusion of temperature, precipitation and vapour pressure deficit is key to predict crop failure. In addition, meteorological predictors during all seasons are required for a good prediction. These results illustrate the omnipresence of compounding effects of both meteorological drivers and different periods of the growing season for creating crop failure events. Especially vapour pressure deficit and climate extreme indicators such as diurnal temperature range and the number of frost days are selected by the statistical model as relevant predictors for crop failure at most grid points, underlining their overarching relevance. We conclude that the LASSO regression model is a useful tool to automatically detect compound drivers of extreme impacts and could be applied to other weather impacts such as wildfires or floods. As the detected relationships are of purely correlative nature, more detailed analyses are required to establish the causal structure between drivers and impacts. Y1 - 2020 U6 - https://doi.org/10.5194/esd-12-151-2021 SN - 2190-4987 SN - 2190-4979 VL - 12 SP - 151 EP - 172 ER - TY - JOUR A1 - Puppe, Daniel A1 - Wanner, Manfred A1 - Sommer, Michael T1 - Data on euglyphid testate amoeba densities, corresponding protozoic silicon pools, and selected soil parameters of initial and forested biogeosystems JF - Data in brief N2 - The dataset in the present article provides information on protozoic silicon (Si) pools represented by euglyphid testate amoebae (TA) in soils of initial and forested biogeosystems. Protozoic Si pools were calculated from densities of euglyphid TA shells and corresponding Si contents. The article also includes data on potential annual biosilicification rates of euglyphid TA at the examined sites. Furthermore, data on selected soil parameters (e.g., readily-available Si, soil pH) and site characteristics (e.g., soil groups, climate data) can be found. The data might be interesting for researchers focusing on biological processes in Si cycling in general and euglyphid TA and corresponding protozoic Si pools in particular. KW - Silicon cycling KW - Biogenic silica KW - Terrestrial biogeosystems KW - Biosilicification KW - Euglyphida Y1 - 2018 U6 - https://doi.org/10.1016/j.dib.2018.10.164 SN - 2352-3409 VL - 21 SP - 1697 EP - 1703 PB - Elsevier CY - Amsterdam ER -