TY - CHAP A1 - Tavangarian, Djamshid A1 - Schroeder, Ulrik A1 - Igel, Christoph A1 - Magenheim, Johannes A1 - Kundisch, Dennis A1 - Beutner, Marc A1 - Herrmann, Philipp A1 - Whittaker, Michael A1 - Reinhardt, Wolfgang A1 - Zoyke, Andrea A1 - Elbeshausen, Stefanie A1 - Griesbaum, Joachim A1 - Koelle, Ralph A1 - Kneiphoff, Anika Hanna A1 - Mauch, Martina A1 - Hübner, Sandra A1 - Walter, Satjawan A1 - Dittler, Ullrich A1 - Baumann, Annette A1 - Reeh, Lucas A1 - Beuster, Liane A1 - Elkina, Margarita A1 - Fortenbacher, Albrecht A1 - Kappe, Leonard A1 - Merceron, Agathe A1 - Pursian, Andreas A1 - Schwarzrock, Sebastian A1 - Wenzlaff, Boris A1 - Hilse, Michael A1 - Lucke, Ulrike ED - Lucke, Ulrike T1 - E-Learning Symposium 2012 BT - Aktuelle Anwendungen, innovative Prozesse und neueste Ergebnisse aus der E-Learning-Praxis ; Potsdam, 17. November 2012 N2 - Dieser Tagungsband beinhaltet die auf dem E-Learning Symposium 2012 an der Universität Potsdam vorgestellten Beiträge zu aktuellen Anwendungen, innovativen Prozesse und neuesten Ergebnissen im Themenbereich E-Learning. Lehrende, E-Learning-Praktiker und -Entscheider tauschten ihr Wissen über etablierte und geplante Konzepte im Zusammenhang mit dem Student-Life-Cycle aus. Der Schwerpunkt lag hierbei auf der unmittelbaren Unterstützung von Lehr- und Lernprozessen, auf Präsentation, Aktivierung und Kooperation durch Verwendung von neuen und etablierten Technologien. KW - E-Learning KW - Learning Analytics KW - lebenslanges Lernen KW - E-Learning KW - Learning Analytics KW - Life-Long Learning Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-62661 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Heisswolf, Annette A1 - Reichmann, Stefanie A1 - Poethke, Hans Joachim A1 - Schroeder, Boris A1 - Obermaier, Elisabeth T1 - Habitat quality matters for the distribution of an endangered leaf beetle and its egg parasitoid in a fragmented landscape N2 - Fragmentation, deterioration, and loss of habitat patches threaten the survival of many insect species. Depending on their trophic level, species may be differently affected by these factors. However, studies investigating more than one trophic level on a landscape scale are still rare. In the present study we analyzed the effects of habitat size, isolation, and quality for the occurrence and population density of the endangered leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) and its egg parasitoid, the hymenopteran wasp Foersterella reptans Nees (Hymenoptera: Tetracampidae). C. canaliculata is strictly monophagous on meadow sage (Salvia pratensis), while F. reptans can also parasitize other hosts. Both size and isolation of habitat patches strongly determined the occurrence of the beetle. However, population density increased to a much greater extent with increasing host plant density ( = habitat quality) than with habitat size. The occurrence probability of the egg parasitoid increased with increasing population density of C. canaliculata. In conclusion, although maintaining large, well-connected patches with high host plant density is surely the major conservation goal for the specialized herbivore C. canaliculata, also small patches with high host plant densities can support viable populations and should thus be conserved. The less specialized parasitoid F. reptans is more likely to be found on patches with high beetle density, while patch size and isolation seem to be less important. Y1 - 2009 UR - http://www.springerlink.com/content/100177 U6 - https://doi.org/10.1007/s10841-008-9139-4 SN - 1366-638X ER - TY - JOUR A1 - Seppelt, Ralf A1 - Mueller, Felix A1 - Schroeder, Boris A1 - Volk, Martin T1 - Challenges of simulating complex environmental systems at the landscape scale : a controversial dialogue between two cups of espresso N2 - With the advancement of computational systems and the development of model integration concepts, complexity of environmental model systems increased. In contrast to that, theory and knowledge about>environmental systems as well as the capability for environmental systems analyses remained, to a large extent, unchanged. As a consequence, model conceptualization, data gathering, and validation, have faced new challenges that hardly can be tackled by modellers alone. In this discourse-like review, we argue that modelling with reliable simulations of human-environmental interactions necessitate linking modelling and simulation research much stronger to science fields such as landscape ecology, community ecology, eco-hydrology, etc. It thus becomes more and more important to identify the adequate degree of complexity in environmental models (which is not only a technical or methodological question), to ensure data availability, and to test model performance. Even equally important, providing problem specific answers to environmental problems using simulation tools requires addressing end-user and stakeholder requirements during early stages of problem development. In doing so, we avoid modelling and simulation as an end of its own. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/03043800 U6 - https://doi.org/10.1016/j.ecolmodel.2009.09.009 SN - 0304-3800 ER - TY - JOUR A1 - Zurell, Damaris A1 - Berger, Uta A1 - Cabral, Juliano Sarmento A1 - Jeltsch, Florian A1 - Meynard, Christine N. A1 - Muenkemueller, Tamara A1 - Nehrbass, Nana A1 - Pagel, Jörn A1 - Reineking, Bjoern A1 - Schroeder, Boris A1 - Grimm, Volker T1 - The virtual ecologist approach : simulating data and observers N2 - Ecologists carry a well-stocked toolbox with a great variety of sampling methods, statistical analyses and modelling tools, and new methods are constantly appearing. Evaluation and optimisation of these methods is crucial to guide methodological choices. Simulating error-free data or taking high-quality data to qualify methods is common practice. Here, we emphasise the methodology of the 'virtual ecologist' (VE) approach where simulated data and observer models are used to mimic real species and how they are 'virtually' observed. This virtual data is then subjected to statistical analyses and modelling, and the results are evaluated against the 'true' simulated data. The VE approach is an intuitive and powerful evaluation framework that allows a quality assessment of sampling protocols, analyses and modelling tools. It works under controlled conditions as well as under consideration of confounding factors such as animal movement and biased observer behaviour. In this review, we promote the approach as a rigorous research tool, and demonstrate its capabilities and practical relevance. We explore past uses of VE in different ecological research fields, where it mainly has been used to test and improve sampling regimes as well as for testing and comparing models, for example species distribution models. We discuss its benefits as well as potential limitations, and provide some practical considerations for designing VE studies. Finally, research fields are identified for which the approach could be useful in the future. We conclude that VE could foster the integration of theoretical and empirical work and stimulate work that goes far beyond sampling methods, leading to new questions, theories, and better mechanistic understanding of ecological systems. Y1 - 2010 UR - http://www3.interscience.wiley.com/cgi-bin/issn?DESCRIPTOR=PRINTISSN&VALUE=0030-1299 U6 - https://doi.org/10.1111/j.1600-0706.2009.18284.x SN - 0030-1299 ER - TY - JOUR A1 - Hothorn, Torsten A1 - Müller, Jörg A1 - Schroeder, Boris A1 - Kneib, Thomas A1 - Brandl, Roland T1 - Decomposing environmental, spatial, and spatiotemporal components of species distributions JF - Ecological monographs : a publication of the Ecological Society of America. N2 - Species distribution models are an important tool to predict the impact of global change on species distributional ranges and community assemblages. Although considerable progress has been made in the statistical modeling during the last decade, many approaches still ignore important features of species distributions, such as nonlinearity and interactions between predictors, spatial autocorrelation, and nonstationarity, or at most incorporate only some of these features. Ecologists, however, require a modeling framework that simultaneously addresses all these features flexibly and consistently. Here we describe such an approach that allows the estimation of the global effects of environmental variables in addition to local components dealing with spatiotemporal autocorrelation as well as nonstationary effects. The local components can be used to infer unknown spatiotemporal processes; the global component describes how the species is influenced by the environment and can be used for predictions, allowing the fitting of many well-known regression relationships, ranging from simple linear models to complex decision trees or from additive models to models inspired by machine learning procedures. The reliability of spatiotemporal predictions can be qualitatively predicted by separately evaluating the importance of local and global effects. We demonstrate the potential of the new approach by modeling the breeding distribution of the Red Kite (Milvus milvus), a bird of prey occurring predominantly in Western Europe, based on presence/absence data from two mapping campaigns using grids of 40 km 2 in Bavaria. The global component of the model selected seven environmental variables extracted from the CORINE and WorldClim databases to predict Red Kite breeding. The effect of altitude was found to be nonstationary in space, and in addition, the data were spatially autocorrelated, which suggests that a species distribution model that does not allow for spatially varying effects and spatial autocorrelation would have ignored important processes determining the distribution of Red Kite breeding across Bavaria. Thus, predictions from standard species distribution models that do not allow for real-world complexities may be considerably erroneous. Our analysis of Red Kite breeding exemplifies the potential of the innovative approach for species distribution models. The method is also applicable to modeling count data. KW - boosting KW - model selection KW - nonstationarity KW - spatial autocorrelation KW - species distribution model KW - structured additive model KW - variable selection Y1 - 2011 U6 - https://doi.org/10.1890/10-0602.1 SN - 0012-9615 VL - 81 IS - 2 SP - 329 EP - 347 PB - Wiley CY - Washington ER - TY - JOUR A1 - Gevers, Jana A1 - Hoye, Toke Thomas A1 - Topping, Chris John A1 - Glemnitz, Michael A1 - Schroeder, Boris T1 - Biodiversity and the mitigation of climate change through bioenergy impacts of increased maize cultivation on farmland wildlife JF - Global change biology : Bioenergy N2 - The public promotion of renewable energies is expected to increase the number of biogas plants and stimulate energy crops cultivation (e. g. maize) in Germany. In order to assess the indirect effects of the resulting land-use changes on biodiversity, we developed six land-use scenarios and simulated the responses of six farmland wildlife species with the spatially explicit agent-based model system ALMaSS. The scenarios differed in composition and spatial configuration of arable crops. We implemented scenarios where maize for energy production replaced 15% and 30% of the area covered by other cash crops. Biogas maize farms were either randomly distributed or located within small or large aggregation clusters. The animal species investigated were skylark (Alauda arvensis), grey partridge (Perdix perdix), European brown hare (Lepus europaeus), field vole (Microtus agrestis), a linyphiid spider (Erigone atra) and a carabid beetle (Bembidion lampros). The changes in crop composition had a negative effect on the population sizes of skylark, partridge and hare and a positive effect on the population sizes of spider and beetle and no effect on the population size of vole. An aggregated cultivation of maize amplified these effects for skylark. Species responses to changes in the crop composition were consistent across three differently structured landscapes. Our work suggests that with the compliance to some recommendations, negative effects of biogas-related land-use change on the populations of the six representative farmland species can largely be avoided. KW - agriculture KW - ALMaSS KW - biogas KW - farmland biodiversity KW - land-use change KW - maize KW - spatially explicit agent-based modeling Y1 - 2011 U6 - https://doi.org/10.1111/j.1757-1707.2011.01104.x SN - 1757-1693 VL - 3 IS - 6 SP - 472 EP - 482 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Loeffler, Jörg A1 - Anschlag, Kerstin A1 - Baker, Barry A1 - Finch, Oliver-D. A1 - Diekkrueger, Bernd A1 - Wundram, Dirk A1 - Schroeder, Boris A1 - Pape, Roland A1 - Lundberg, Anders T1 - Mountain ecosystem response to global change JF - Erdkunde : archive for scientific geography N2 - Mountain ecosystems are commonly regarded as being highly sensitive to global change. Due to the system complexity and multifaceted interacting drivers, however, understanding current responses and predicting future changes in these ecosystems is extremely difficult. We aim to discuss potential effects of global change on mountain ecosystems and give examples of the underlying response mechanisms as they are understood at present. Based on the development of scientific global change research in mountains and its recent structures, we identify future research needs, highlighting the major lack and the importance of integrated studies that implement multi-factor, multi-method, multi-scale, and interdisciplinary research. KW - High mountain ecology KW - arctic-alpine environments KW - climate change KW - land use and land cover change KW - tree line alteration KW - range shifts KW - altitudinal zonation Y1 - 2011 U6 - https://doi.org/10.3112/erdkunde.2011.02.06 SN - 0014-0015 VL - 65 IS - 2 SP - 189 EP - 213 PB - Geographisches Inst., Univ. Bonn CY - Goch ER - TY - JOUR A1 - Maerker, Michael A1 - Pelacani, Samanta A1 - Schroeder, Boris T1 - A functional entity approach to predict soil erosion processes in a small Plio-Pleistocene Mediterranean catchment in Northern Chianti, Italy JF - Geomorphology : an international journal on pure and applied geomorphology N2 - In this paper we evaluate different methods to predict soil erosion processes. We derived different layers of predictor variables for the study area in the Northern Chianti, Italy, describing the soil-lithologic complex, land use, and topographic characteristics. For a subcatchment of the Orme River, we mapped erosion processes by interpreting aerial photographs and field observations. These were classified as erosional response units (ERU), i.e. spatial areas of homogeneous erosion processes. The ERU were used as the response variable in the soil erosion modelling process. We applied two models i) bootstrap aggregation (Random Forest: RF), and ii) stochastic gradient boosting (TreeNet: TN) to predict the potential spatial distribution of erosion processes for the entire Orme River catchment. The models are statistically evaluated using training data and a set of performance parameters such as the area under the receiver operating characteristic curve (AUC), Cohen's Kappa, and pseudo R2. Variable importance and response curves provide further insight into controlling factors of erosion. Both models provided good performance in terms of classification and calibration; however, TN outperformed RF. Similar classes such as active and inactive landslides can be discriminated and well interpreted by considering response curves and relative variable importance. The spatial distribution of the predicted erosion susceptibilities generally follows topographic constraints and is similar for both models. Hence, the model-based delineation of ERU on the basis of soil and terrain information is a valuable tool in geomorphology; it provides insights into factors controlling erosion processes and may allow the extrapolation and prediction of erosion processes in unsurveyed areas. KW - Erosion processes KW - Boostrap aggregation KW - Stochastic gradient boosting KW - Spatially explicit prediction KW - Tuscany KW - Italy Y1 - 2011 U6 - https://doi.org/10.1016/j.geomorph.2010.10.022 SN - 0169-555X VL - 125 IS - 4 SP - 530 EP - 540 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - van Schaik, Loes A1 - Palm, Juliane A1 - Klaus, Julian A1 - Zehe, Erwin A1 - Schroeder, Boris T1 - Linking spatial earthworm distribution to macropore numbers and hydrological effectiveness JF - Ecohydrology : ecosystems, land and water process interactions, ecohydrogeomorphology N2 - Due to its high spatial and temporal variability, preferential flow is difficult to measure and quantify. Earthworms create macropores that provide common pathways for preferential flow. Therefore in this article, we link earthworm abundance to macropore numbers and hydrological effectiveness, with the future aim to use species distribution models of earthworms for the spatial parameterization of preferential flow. Earthworms are generally categorized into three ecological types with varying burrowing behaviour, resulting in a different impact on soil hydrological processes. Therefore, we studied the relationships between the abundance of the earthworm ecological types and macropores of different size classes and in different soil depths. The abundance and biomass of earthworms were well correlated to different sizes of macropores in different soil depths. This is mainly the case for the larger, vertically oriented macropores (>6mm diameter), which are generally connected to the soil surface and hydrologically most effective. The correlation of total earthworm biomass and macropores ranges from 072 to 089 for different soil depths. Although there is quite some variation in infiltration patterns, infiltration from macropores into the matrix is profile-specific, as it varies strongly between profiles, but not within one profile. Macropore coating seems to have a larger effect on this macropore matrix interaction than the soil physical properties of the matrix. Although the amount of macropores and their effectiveness are clearly related to the earthworm distribution, the variation in infiltration from macropores to soil matrix should be further studied. KW - macropores KW - spatial parameterization KW - earthworm ecological types KW - infiltration patterns KW - preferential flow Y1 - 2014 U6 - https://doi.org/10.1002/eco.1358 SN - 1936-0584 SN - 1936-0592 VL - 7 IS - 2 SP - 401 EP - 408 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Schibalski, Anett A1 - Lehtonen, Aleksi A1 - Schroeder, Boris T1 - Climate change shifts environmental space and limits transferability of treeline models JF - Ecography : pattern and diversity in ecology ; research papers forum N2 - Our study aims at gaining insights into the processes determining the current treeline dynamics in Finnish Lapland. Using forest surveys conducted in 1978 and 2003 we modelled the occurrence and abundance of three dominant tree species in Finnish Lapland, i.e. Pinus sylvestris, Picea abies and Betula pubescens, with boosted regression trees. We assessed the importance of climatic, biotic and topographic variables in predicting tree occurrence and abundance based on their relative importance and response curves. We compared temporal and spatial transferability by using an extended transferability index. Site fertility, the abundance of co-occurring species and growing degree days were generally the most important predictors for both occurrence and abundance across all species and datasets. Climatic predictors were more important for modelling occurrences than for modelling abundances. Occurrence models were able to reproduce the observed treeline pattern within one time period or region. Abundance models underestimated basal area but captured the general pattern of low and high values. Model performance as well as transferability differed considerably between species and datasets. Pinus sylvestris was modelled more successfully than P. abies and B. pubescens. Generally, spatial transferability was greater than temporal transferability. Comparing the environmental space between datasets revealed that transferring models means extrapolating to novel environments, providing a plausible explanation for limited transferability. Our study illustrates how climate change can shift the environmental space and lead to limited model transferability. We identified non-climatic factors to be important in predicting the distribution of dominant tree species, contesting the widespread assumption of climatically induced range expansion. Y1 - 2014 U6 - https://doi.org/10.1111/j.1600-0587.2013.00368.x SN - 0906-7590 SN - 1600-0587 VL - 37 IS - 4 SP - 321 EP - 335 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Krause, Rolf Harald A1 - Buse, Joern A1 - Matern, Andrea A1 - Schroeder, Boris A1 - Haerdtle, Werner A1 - Assmann, Thorsten T1 - Eresus kollari (Araneae: Eresidae) calls for heathland management JF - The Journal of arachnology N2 - Northwest Europe's largest heather-dominated sandy habitats are located in the nature reserve Luneburger Heide, Germany. Yet, even these appear to be losing their ability to support some of their stenotopic species such as the ladybird spider, Eresus kollari Rossi 1846, and are thus becoming increasingly important for the preservation of these species. The habitat requirements of this endangered spider species were investigated in order to obtain data that will help stabilize the last remnants of the species' population in northwest Germany. Several heathland habitats were surveyed by pitfall trapping during the mate-search period of the males. Two statistical methods were applied: logistic regression and boosted regression trees (BRT). Both methods showed that three habitat variables are of prime relevance in predicting the occurrence of E. kollari: a) thickness of the organic layer (a negative effect), b) soil temperature at a depth of 10 cm, and c) Calluna cover in the herb layer (both have positive effect). Our results show that choppering (removing above-ground biomass and most of O-layer) and burning are likely appropriate heathland management measures for the conservation of E. kollari. Such measures improve the species' habitat quality by creating a heterogenic (small-scaled) heathland structure with suitable microhabitats. As Calluna heathlands show a clear senescence of the dominant heather, it is essential that those habitat patches be conserved. Further measures, such as transfer experiments, are recommended. KW - Conservation management KW - habitat modeling KW - action plan KW - choppering KW - burning Y1 - 2011 SN - 0161-8202 SN - 1937-2396 VL - 39 IS - 3 SP - 384 EP - 392 PB - American Arachnological Society CY - College Park ER - TY - JOUR A1 - Klaus, Julian A1 - Zehe, Erwin A1 - Elsner, Martin A1 - Palm, Juliane A1 - Schneider, Dorothee A1 - Schroeder, Boris A1 - Steinbeiss, Sibylle A1 - van Schaik, Loes A1 - West, Stephanie T1 - Controls of event-based pesticide leaching in natural soils: A systematic study based on replicated field scale irrigation experiments JF - Journal of hydrology N2 - Tile drains strongly influence the water cycle in agricultural catchment in terms of water quantity and quality. The connectivity of preferential flow to tile drains can create shortcuts for rapid transport of solutes into surface waters. The leaching of pesticides can be linked to a set of main factors including, rainfall characteristics, soil moisture, chemical properties of the pesticides, soil properties, and preferential flow paths. The connectivity of the macropore system to the tile drain is crucial for pesticide leaching. Concurring influences of the main factors, threshold responses and the role of flow paths are still poorly understood. The objective of this study is to investigate these influences by a replica series of three irrigation experiments on a tile drain field site using natural and artificial tracers together with applied pesticides. We found a clear threshold behavior in the initialization of pesticide transport that was different between the replica experiments. Pre-event soil water contributed significantly to the tile drain flow, and creates a flow path for stored pesticides from the soil matrix to the tile drain. This threshold is controlled by antecedent soil moisture and precipitation characteristics, and the interaction between the soil matrix and preferential flow system. Fast transport of pesticides without retardation and the remobilization could be attributed to this threshold and the interaction between the soil matrix and the preferential flow system. Thus, understanding of the detailed preferential flow processes clearly enhances the understanding of pesticide leaching on event and long term scale, and can further improve risk assessment and modeling approaches. (C) 2014 Elsevier B.V. All rights reserved. KW - Irrigation experiment KW - Preferential flow KW - Threshold KW - Pesticide transport Y1 - 2014 U6 - https://doi.org/10.1016/j.jhydrol.2014.03.020 SN - 0022-1694 SN - 1879-2707 VL - 512 SP - 528 EP - 539 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Carus, Jana A1 - Paul, Maike A1 - Schroeder, Boris T1 - Vegetation as self-adaptive coastal protection: Reduction of current velocity and morphologic plasticity of a brackish marsh pioneer JF - Ecology and evolution N2 - By reducing current velocity, tidal marsh vegetation can diminish storm surges and storm waves. Conversely, currents often exert high mechanical stresses onto the plants and hence affect vegetation structure and plant characteristics. In our study, we aim at analysing this interaction from both angles. On the one hand, we quantify the reduction of current velocity by Bolboschoenus maritimus, and on the other hand, we identify functional traits of B. maritimus’ ramets along environmental gradients. Our results show that tidal marsh vegetation is able to buffer a large proportion of the flow velocity at currents under normal conditions. Cross-shore current velocity decreased with distance from the marsh edge and was reduced by more than 50% after 15 m of vegetation. We were furthermore able to show that plants growing at the marsh edge had a significantly larger diameter than plants from inside the vegetation. We found a positive correlation between plant thickness and cross-shore current which could provide an adaptive value in habitats with high mechanical stress. With the adapted morphology of plants growing at the highly exposed marsh edge, the entire vegetation belt is able to better resist the mechanical stress of high current velocities. This self-adaptive effect thus increases the ability of B. maritimus to grow and persist in the pioneer zone and may hence better contribute to ecosystem-based coastal protection by reducing current velocity. KW - Adaptive value KW - Bolboschoenus maritimus KW - brackish marsh KW - flow velocity KW - mechanical pressure KW - morphological adaptation KW - phenotypic plasticity KW - pioneer zone Y1 - 2016 U6 - https://doi.org/10.1002/ece3.1904 SN - 2045-7758 VL - 6 SP - 1579 EP - 1589 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - van Schaik, Loes A1 - Palm, Juliane A1 - Klaus, Julian A1 - Zehe, Erwin A1 - Schroeder, Boris T1 - Potential effects of tillage and field borders on within-field spatial distribution patterns of earthworms JF - Biological chemistry N2 - Earthworms play a key role in regulating soil ecosystem functions and services. The small scale variability in earthworm abundance is often found to be very high, which is a problem for representative sampling of earthworm abundance at larger scales. In agricultural fields, soil tillage may influence both the average earthworm abundance as well as the spatial distribution of earthworms. Therefore we studied the abundance and spatial pattern of the different ecological earthworm types, i.e. endogeic, epigeic and anecic earthworms, in four agricultural fields differing in soil tillage (two fields with regular tillage and two fields with conservation tillage) and surrounding land use (other cropped fields or apple orchard and forest). To this aim we sampled earthworms on a total number of 430 plots (50 x 50 cm(2)) using a combination of extraction with mustard solution and hand sorting. The results exhibit large differences in average earthworm abundance between the four fields. Only one of the two fields with conservation tillage had a comparatively very high overall abundance of earthworms. Furthermore, we found a high spatial variability of earthworms within the field scale often exhibiting a patchy distribution. We detected a trend of decreasing earthworm abundances from the field border into the field for different earthworm groups on each of the fields. In three fields with low total earthworm abundance (and only very few epigeic earthworms) there was a short scale autocorrelation with ranges varying strongly for the endogeic earthworms (37.9 m, 62.6 m, and 85.2 m) compared to anecic earthworms (19.8 m, 22.8 m, and 27.4 m). In the field with high abundance, after trend removal, the variogram models for anecic and endogeic earthworms were rejected based on their negative explained variances. On this field, we found only a short scale autocorrelation for the epigeic earthworms with a range of 143 m. Based on these results it seems that ploughing alone cannot explain the differences in abundance and range of autocorrelation found on the four fields. The trend of strongly decreasing earthworm abundance from the field border into the field in the one field with high abundance does indicate that the field border or surrounding land use may also influence the recolonization of fields, but more research is required to provide further evidence for this hypothesis. Due to the very different patterns of earthworm distributions in the fields it remains difficult to recommend an optimal number and distance of samples to obtain a representative earthworm abundance for the field scale. (C) 2016 Elsevier B.V. All rights reserved. KW - Earthworms KW - Spatial distribution KW - Autocorrelation KW - Agricultural fields KW - Soil tillage Y1 - 2016 U6 - https://doi.org/10.1016/j.agee.2016.05.015 SN - 0167-8809 SN - 1873-2305 VL - 228 SP - 82 EP - 90 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Brandt, Karoline A1 - Glemnitz, M. A1 - Schroeder, Boris T1 - The impact of crop parameters and surrounding habitats on different pollinator group abundance on agricultural fields JF - Agriculture, ecosystems & environment : an international journal for scientific research on the relationship of agriculture and food production to the biosphere N2 - Pollination is a key ecosystem service. Pollinators, however, are in decline and their service is increasingly threatened. The decline is driven by several factors, most of which are related to agricultural management. However, the complexity of the landscape system, consisting of both cropped and non cropped areas, makes it difficult to address or even quantify the role of farming practices in pollinator abundance. Therefore, the aim of this paper is to improve our understanding of the relationships between pollinator abundance and their habitat use. We intend to identify and quantify the driving environmental factors that determine pollinator abundance in agricultural landscapes on the crop and landscape scale. These information helps us to design algorithms that can be used as a basis for predicting pollinator abundance on agricultural fields. To integrate varying environmental conditions data sampling was performed on farms in three different regions in Germany. Pollinators were classified into different groups with three aggregation levels. We observed crop parameters as well as landscape parameters in the areas surrounding fields in addition to temporal aspects. Generalized linear models (GLMs) were then calculated. Our results showed that both crop and landscape parameters affect pollinator abundance on agricultural fields. However, the explanatory power of the included parameters varied strongly among the particular pollinator groups and between aggregation levels. Furthermore, differentiation between species groups improves the explanatory power compared to models that are more aggregated. We also found that the temporal match between main activity periods of the particular pollinator groups and resource supply by the crop species is a key factor when analysing pollinator abundance. In conclusion, we demonstrated that the assessment and support of pollination services should be carried out with regard to individual pollinator groups. When studying pollinator abundance, the crop as well as the landscape scale should be addressed. A range of different habitat requirements and different activity periods of the pollinator groups must be covered to maintain pollination services, and therefore both diverse landscapes and diverse crop rotations are of crucial importance. (C) 2017 Elsevier B.V. All rights reserved. KW - Species distribution models KW - Generalized linear models (GLMs) KW - Environmental drivers KW - Habitat suitability KW - Pollinator conservation KW - Wild bees Y1 - 2017 U6 - https://doi.org/10.1016/j.agee.2017.03.009 SN - 0167-8809 SN - 1873-2305 VL - 243 SP - 55 EP - 66 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Gräff, Thomas A1 - Zehe, Erwin A1 - Reusser, Dominik A1 - Lueck, Erika A1 - Schroeder, Boris A1 - Wenk, Gerald A1 - John, Hermann A1 - Bronstert, Axel T1 - Process identification through rejection of model structures in a mid-mountainous rural catchment : observations of rainfall-runoff response, geophysical conditions and model inter-comparison N2 - The intention of the presented study is to gain a better understanding of the mechanisms that caused the bimodal rainfall-runoff responses which occurred up to the mid-1970s regularly in the Schafertal catchment and vanished after the onset of mining activities. Understanding, this process is a first step to understanding the ongoing hydrological change in this area. It is hypothesized that either subsurface stormflow, or fast displacement of groundwater, could cause the second delayed peak. A top-down analysis of rainfall-runoff data, field observations as well as process modelling are combined within a rejectionistic framework. A statistical analysis is used to test whether different predictors. which characterize the forcing. near surface water content and deeper subsurface store, allow the prediction of the type of rainfall-runoff response. Regression analysis is used with generalized linear models Lis they can deal with non-Gaussian error distributions Lis well its a non-stationary variance. The analysis reveals that the dominant predictors are the pre-event discharge (proxy of state of the groundwater store) and the precipitation amount, In the field campaign, the subsurface at a representative hillslope was investigated by means of electrical resistivity tomography in order to identify possible strata as flow paths for subsurface stormflow. A low resistivity in approximately 4 in depth-either due to a less permeable layer or the groundwater surface-was detected. The former Could serve as a flow path for subsurface stormflow. Finally, the physical-based hydrological model CATFLOW and the groundwater model FEFLOW are compared with respect to their ability to reproduce the bimodal runoff responses. The groundwater model is able to reproduce the observations, although it uses only an abstract representation of the hillslopes. Process model analysis as well Lis statistical analysis strongly suggest that fast displacement of groundwater is the dominant process underlying the bimodal runoff reactions. Y1 - 2009 UR - http://www3.interscience.wiley.com/journal/4125/home U6 - https://doi.org/10.1002/Hyp.7171 SN - 0885-6087 ER - TY - JOUR A1 - Jeltsch, Florian A1 - Blaum, Niels A1 - Brose, Ulrich A1 - Chipperfield, Joseph D. A1 - Clough, Yann A1 - Farwig, Nina A1 - Geissler, Katja A1 - Graham, Catherine H. A1 - Grimm, Volker A1 - Hickler, Thomas A1 - Huth, Andreas A1 - May, Felix A1 - Meyer, Katrin M. A1 - Pagel, Jörn A1 - Reineking, Björn A1 - Rillig, Matthias C. A1 - Shea, Katriona A1 - Schurr, Frank Martin A1 - Schroeder, Boris A1 - Tielbörger, Katja A1 - Weiss, Lina A1 - Wiegand, Kerstin A1 - Wiegand, Thorsten A1 - Wirth, Christian A1 - Zurell, Damaris T1 - How can we bring together empiricists and modellers in functional biodiversity research? JF - Basic and applied ecology : Journal of the Gesellschaft für Ökologie N2 - Improving our understanding of biodiversity and ecosystem functioning and our capacity to inform ecosystem management requires an integrated framework for functional biodiversity research (FBR). However, adequate integration among empirical approaches (monitoring and experimental) and modelling has rarely been achieved in FBR. We offer an appraisal of the issues involved and chart a course towards enhanced integration. A major element of this path is the joint orientation towards the continuous refinement of a theoretical framework for FBR that links theory testing and generalization with applied research oriented towards the conservation of biodiversity and ecosystem functioning. We further emphasize existing decision-making frameworks as suitable instruments to practically merge these different aims of FBR and bring them into application. This integrated framework requires joint research planning, and should improve communication and stimulate collaboration between modellers and empiricists, thereby overcoming existing reservations and prejudices. The implementation of this integrative research agenda for FBR requires an adaptation in most national and international funding schemes in order to accommodate such joint teams and their more complex structures and data needs. KW - Biodiversity theory KW - Biodiversity experiments KW - Conservation management KW - Decision-making KW - Ecosystem functions and services KW - Forecasting KW - Functional traits KW - Global change KW - Monitoring programmes KW - Interdisciplinarity Y1 - 2013 U6 - https://doi.org/10.1016/j.baae.2013.01.001 SN - 1439-1791 VL - 14 IS - 2 SP - 93 EP - 101 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Zehe, E. A1 - Ehret, U. A1 - Pfister, L. A1 - Blume, Theresa A1 - Schroeder, Boris A1 - Westhoff, M. A1 - Jackisch, C. A1 - Schymanski, Stanislauv J. A1 - Weiler, M. A1 - Schulz, K. A1 - Allroggen, Niklas A1 - Tronicke, Jens A1 - van Schaik, Loes A1 - Dietrich, Peter A1 - Scherer, U. A1 - Eccard, Jana A1 - Wulfmeyer, Volker A1 - Kleidon, Axel T1 - HESS Opinions: From response units to functional units: a thermodynamic reinterpretation of the HRU concept to link spatial organization and functioning of intermediate scale catchments JF - Hydrology and earth system sciences : HESS N2 - According to Dooge (1986) intermediate-scale catchments are systems of organized complexity, being too organized and yet too small to be characterized on a statistical/conceptual basis, but too large and too heterogeneous to be characterized in a deterministic manner. A key requirement for building structurally adequate models precisely for this intermediate scale is a better understanding of how different forms of spatial organization affect storage and release of water and energy. Here, we propose that a combination of the concept of hydrological response units (HRUs) and thermodynamics offers several helpful and partly novel perspectives for gaining this improved understanding. Our key idea is to define functional similarity based on similarity of the terrestrial controls of gradients and resistance terms controlling the land surface energy balance, rainfall runoff transformation, and groundwater storage and release. This might imply that functional similarity with respect to these specific forms of water release emerges at different scales, namely the small field scale, the hillslope, and the catchment scale. We thus propose three different types of "functional units" - specialized HRUs, so to speak - which behave similarly with respect to one specific form of water release and with a characteristic extent equal to one of those three scale levels. We furthermore discuss an experimental strategy based on exemplary learning and replicate experiments to identify and delineate these functional units, and as a promising strategy for characterizing the interplay and organization of water and energy fluxes across scales. We believe the thermodynamic perspective to be well suited to unmask equifinality as inherent in the equations governing water, momentum, and energy fluxes: this is because several combinations of gradients and resistance terms yield the same mass or energy flux and the terrestrial controls of gradients and resistance terms are largely independent. We propose that structurally adequate models at this scale should consequently disentangle driving gradients and resistance terms, because this optionally allow sequifinality to be partly reduced by including available observations, e. g., on driving gradients. Most importantly, the thermodynamic perspective yields an energy-centered perspective on rainfall-runoff transformation and evapotranspiration, including fundamental limits for energy fluxes associated with these processes. This might additionally reduce equifinality and opens up opportunities for testing thermodynamic optimality principles within independent predictions of rainfall-runoff or land surface energy exchange. This is pivotal to finding out whether or not spatial organization in catchments is in accordance with a fundamental organizing principle. Y1 - 2014 U6 - https://doi.org/10.5194/hess-18-4635-2014 SN - 1027-5606 SN - 1607-7938 VL - 18 IS - 11 SP - 4635 EP - 4655 PB - Copernicus CY - Göttingen ER -