TY - JOUR A1 - Dormann, Carsten F. A1 - Elith, Jane A1 - Bacher, Sven A1 - Buchmann, Carsten M. A1 - Carl, Gudrun A1 - Carre, Gabriel A1 - Garcia Marquez, Jaime R. A1 - Gruber, Bernd A1 - Lafourcade, Bruno A1 - Leitao, Pedro J. A1 - Münkemüller, Tamara A1 - McClean, Colin A1 - Osborne, Patrick E. A1 - Reineking, Bjoern A1 - Schröder-Esselbach, Boris A1 - Skidmore, Andrew K. A1 - Zurell, Damaris A1 - Lautenbach, Sven T1 - Collinearity a review of methods to deal with it and a simulation study evaluating their performance JF - Ecography : pattern and diversity in ecology ; research papers forum N2 - Collinearity refers to the non independence of predictor variables, usually in a regression-type analysis. It is a common feature of any descriptive ecological data set and can be a problem for parameter estimation because it inflates the variance of regression parameters and hence potentially leads to the wrong identification of relevant predictors in a statistical model. Collinearity is a severe problem when a model is trained on data from one region or time, and predicted to another with a different or unknown structure of collinearity. To demonstrate the reach of the problem of collinearity in ecology, we show how relationships among predictors differ between biomes, change over spatial scales and through time. Across disciplines, different approaches to addressing collinearity problems have been developed, ranging from clustering of predictors, threshold-based pre-selection, through latent variable methods, to shrinkage and regularisation. Using simulated data with five predictor-response relationships of increasing complexity and eight levels of collinearity we compared ways to address collinearity with standard multiple regression and machine-learning approaches. We assessed the performance of each approach by testing its impact on prediction to new data. In the extreme, we tested whether the methods were able to identify the true underlying relationship in a training dataset with strong collinearity by evaluating its performance on a test dataset without any collinearity. We found that methods specifically designed for collinearity, such as latent variable methods and tree based models, did not outperform the traditional GLM and threshold-based pre-selection. Our results highlight the value of GLM in combination with penalised methods (particularly ridge) and threshold-based pre-selection when omitted variables are considered in the final interpretation. However, all approaches tested yielded degraded predictions under change in collinearity structure and the folk lore'-thresholds of correlation coefficients between predictor variables of |r| >0.7 was an appropriate indicator for when collinearity begins to severely distort model estimation and subsequent prediction. The use of ecological understanding of the system in pre-analysis variable selection and the choice of the least sensitive statistical approaches reduce the problems of collinearity, but cannot ultimately solve them. Y1 - 2013 U6 - https://doi.org/10.1111/j.1600-0587.2012.07348.x SN - 0906-7590 SN - 1600-0587 VL - 36 IS - 1 SP - 27 EP - 46 PB - Wiley-Blackwell CY - Hoboken ER - TY - GEN A1 - Schröder, Florian A1 - Lisso, Janina A1 - Lange, Peggy A1 - Müssig, Carsten T1 - The extracellular EXO protein mediates cell expansion in Arabidopsis leaves N2 - Background: The EXO (EXORDIUM) gene was identified as a potential mediator of brassinosteroid (BR)-promoted growth. It is part of a gene family with eight members in Arabidopsis. EXO gene expression is under control of BR, and EXO overexpression promotes shoot and root growth. In this study, the consequences of loss of EXO function are described. Results: The exo loss of function mutant showed diminished leaf and root growth and reduced biomass production. Light and scanning electron microscopy analyses revealed that impaired leaf growth is due to reduced cell expansion. Epidermis, palisade, and spongy parenchyma cells were smaller in comparison to the wild-type. The exo mutant showed reduced brassinolide-induced cotyledon and hypocotyl growth. In contrast, exo roots were significantly more sensitive to the inhibitory effect of synthetic brassinolide. Apart from reduced growth, exo did not show severe morphological abnormalities. Gene expression analyses of leaf material identified genes that showed robust EXO-dependent expression. Growth-related genes such as WAK1, EXP5, and KCS1, and genes involved in primary and secondary metabolism showed weaker expression in exo than in wild-type plants. However, the vast majority of BR-regulated genes were normally expressed in exo. HA- and GFP-tagged EXO proteins were targeted to the apoplast. Conclusion: The EXO gene is essential for cell expansion in leaves. Gene expression patterns and growth assays suggest that EXO mediates BR-induced leaf growth. However, EXO does not control BR-levels or BR-sensitivity in the shoot. EXO presumably is involved in a signalling process which coordinates BR-responses with environmental or developmental signals. The hypersensitivity of exo roots to BR suggests that EXO plays a diverse role in the control of BR responses in the root. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 139 KW - Plant transformation KW - Gene expression KW - Wall proteins KW - Thaliana KW - Brassinosteroids Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-45107 ER - TY - JOUR A1 - Berndt, Klaus-Peter A1 - Felgentreff, Carsten A1 - Giest, Hartmut A1 - Walgenbach, Wilhelm A1 - Greil, Holle A1 - Jürgens, H.-W. A1 - Schröder, I. A1 - Scheffler, Christiane A1 - Schilitz, Anja A1 - Segert, Astrid A1 - Zierke, Irene A1 - Wipper, Renate T1 - Umweltforschung für das Land Brandenburg BT - Projekt Humanökologie, Umweltbezogene Handlungsstrukturen, Umweltbildung JF - Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Potsdam N2 - BERNDT, K.-P.: Interdisziplinäres multimediales Lehr- und Lernprojekt "Biodiversität in Großökosystemen" ; FELGENTREFF, C.: Hochwasser im Kontext. Zur Rekonstruktion des Oderhochwassers 1997 in Brandenburg und seiner Folgen ; GIEST, H.; WALGENBACH, W.: Entwicklung von Multimedia-Bausteinen zur Ökologischen Grundbildung ; GREIL, H. et al.: Anthropometrische Grundlagen für die Entwicklung maßgerechter 3D-Computersimulationen des menschlichen Körpers zum Einsatz bei der Gestaltung körpernaher Umweltelemente ; SCHEFFLER, C. et al.: Maß- und funktionsgerechte Gestaltung der körpernahen Umwelt älterer Menschen ; SCHILITZ, A. et al.: Körperliche Entwicklung von Brandenburger Schülern und Schülerinnen als Indikator für komplexe Veränderungen von Umweltbedingungen ; SEGERT, A.; ZIERKE, I.: Handlungsstrukturen in einer ökologisch orientierten Genossenschaft ; WIPPER, R.: Interaktive multimediale Bildungssoftware "Ökosystem Wald - Artenvielfalt in Brandenburg" Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3812 SN - 1434-2375 SN - 1611-9339 VL - 8 SP - 12 EP - 52 ER - TY - JOUR A1 - Lisso, Janina A1 - Schröder, Florian A1 - Müssig, Carsten T1 - EXO modifies sucrose and trehalose responses and connects the extracellular carbon status to growth JF - Frontiers in plant science N2 - Plants have the capacity to adapt growth to changing environmental conditions. This implies the modulation of metabolism according to the availability of carbon (C). Particular interest in the response to the C availability is based on the increasing atmospheric levels of CO2. Several regulatory pathways that link the C status to growth have emerged. The extracellular EXO protein is essential for cell expansion and promotes shoot and root growth. Homologous proteins were identified in evolutionarily distant green plants. We show here that the EXO protein connects growth with C responses. The exo mutant displayed altered responses to exogenous sucrose supplemented to the growth medium. Impaired growth of the mutant in synthetic medium was associated with the accumulation of starch and anthocyanins, altered expression of sugar-responsive genes, and increased abscisic acid levels. Thus, EXO modulates several responses related to the C availability. Growth retardation on medium supplemented with 2-deoxy-glucose, mannose, and palatinose was similar to the wildtype. Trehalose feeding stimulated root growth and shoot biomass production of exoplants where as it inhibited growth of the wildtype. The phenotypic features of the exo mutant suggest that apoplastic processes coordinate growth and C responses. KW - EXO KW - growth KW - sugar response KW - trehalose KW - apoplast Y1 - 2013 U6 - https://doi.org/10.3389/fpls.2013.00219 SN - 1664-462X VL - 4 IS - 25 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Zurell, Damaris A1 - Jeltsch, Florian A1 - Dormann, Carsten F. A1 - Schröder-Esselbach, Boris T1 - Static species distribution models in dynamically changing systems : how good can predictions really be? N2 - SDM performance varied for different range dynamics. Prediction accuracies decreased when abrupt range shifts occurred as species were outpaced by the rate of climate change, and increased again when a new equilibrium situation was realised. When ranges contracted, prediction accuracies increased as the absences were predicted well. Far- dispersing species were faster in tracking climate change, and were predicted more accurately by SDMs than short- dispersing species. BRTs mostly outperformed GLMs. The presence of a predator, and the inclusion of its incidence as an environmental predictor, made BRTs and GLMs perform similarly. Results are discussed in light of other studies dealing with effects of ecological traits and processes on SDM performance. Perspectives are given on further advancements of SDMs and for possible interfaces with more mechanistic approaches in order to improve predictions under environmental change. Y1 - 2009 UR - http://www3.interscience.wiley.com/journal/117966123/home?CRETRY=1&SRETRY=0 U6 - https://doi.org/10.1111/j.1600-0587.2009.05810.x SN - 0906-7590 ER - TY - JOUR A1 - Dormann, Carsten F. A1 - Schymanski, Stanislaus J. A1 - Cabral, Juliano Sarmento A1 - Chuine, Isabelle A1 - Graham, Catherine A1 - Hartig, Florian A1 - Kearney, Michael A1 - Morin, Xavier A1 - Römermann, Christine A1 - Schröder-Esselbach, Boris A1 - Singer, Alexander T1 - Correlation and process in species distribution models: bridging a dichotomy JF - Journal of biogeography N2 - Within the field of species distribution modelling an apparent dichotomy exists between process-based and correlative approaches, where the processes are explicit in the former and implicit in the latter. However, these intuitive distinctions can become blurred when comparing species distribution modelling approaches in more detail. In this review article, we contrast the extremes of the correlativeprocess spectrum of species distribution models with respect to core assumptions, model building and selection strategies, validation, uncertainties, common errors and the questions they are most suited to answer. The extremes of such approaches differ clearly in many aspects, such as model building approaches, parameter estimation strategies and transferability. However, they also share strengths and weaknesses. We show that claims of one approach being intrinsically superior to the other are misguided and that they ignore the processcorrelation continuum as well as the domains of questions that each approach is addressing. Nonetheless, the application of process-based approaches to species distribution modelling lags far behind more correlative (process-implicit) methods and more research is required to explore their potential benefits. Critical issues for the employment of species distribution modelling approaches are given, together with a guideline for appropriate usage. We close with challenges for future development of process-explicit species distribution models and how they may complement current approaches to study species distributions. KW - Hypothesis generation KW - mechanistic model KW - parameterization KW - process-based model KW - species distribution model KW - SDM KW - uncertainty KW - validation Y1 - 2012 U6 - https://doi.org/10.1111/j.1365-2699.2011.02659.x SN - 0305-0270 VL - 39 IS - 12 SP - 2119 EP - 2131 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Schröder, Florian A1 - Lisso, Janina A1 - Muessig, Carsten T1 - Exordium-Like1 promotes growth during low carbon availability in arabidopsis JF - Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants N2 - Little is known about genes that control growth and development under low carbon (C) availability. The Arabidopsis (Arabidopsis thaliana) EXORDIUM-LIKE1 (EXL1) gene (At1g35140) was identified as a brassinosteroid-regulated gene in a previous study. We show here that the EXL1 protein is required for adaptation to C-and energy-limiting growth conditions. In-depth analysis of EXL1 transcript levels under various environmental conditions indicated that EXL1 expression is controlled by the C and energy status. Sugar starvation, extended night, and anoxia stress induced EXL1 gene expression. The C status also determined EXL1 protein levels. These results suggested that EXL1 is involved in the C-starvation response. Phenotypic changes of an exl1 loss-of-function mutant became evident only under corresponding experimental conditions. The mutant showed diminished biomass production in a short-day/low-light growth regime, impaired survival during extended night, and impaired survival of anoxia stress. Basic metabolic processes and signaling pathways are presumed to be barely impaired in exl1, because the mutant showed wild-type levels of major sugars, and transcript levels of only a few genes such as QUA-QUINE STARCH were altered. Our data suggest that EXL1 is part of a regulatory pathway that controls growth and development when C and energy supply is poor. Y1 - 2011 U6 - https://doi.org/10.1104/pp.111.177204 SN - 0032-0889 VL - 156 IS - 3 SP - 1620 EP - 1630 PB - American Society of Plant Physiologists CY - Rockville ER - TY - JOUR A1 - Lisso, Janina A1 - Schröder, Florian A1 - Fisahn, Joachim A1 - Muessig, Carsten T1 - NFX1-LIKE2 (NFXL2) Suppresses Abscisic Acid Accumulation and Stomatal Closure in Arabidopsis thaliana JF - PLoS one N2 - The NFX1-LIKE1 (NFXL1) and NFXL2 genes were identified as regulators of salt stress responses. The NFXL1 protein is a nuclear factor that positively affects adaptation to salt stress. The nfxl1-1 loss-of-function mutant displayed reduced survival rates under salt and high light stress. In contrast, the nfxl2-1 mutant, defective in the NFXL2 gene, and NFXL2-antisense plants exhibited enhanced survival under these conditions. We show here that the loss of NFXL2 function results in abscisic acid (ABA) overaccumulation, reduced stomatal conductance, and enhanced survival under drought stress. The nfxl2-1 mutant displayed reduced stomatal aperture under all conditions tested. Fusicoccin treatment, exposition to increasing light intensities, and supply of decreasing CO2 concentrations demonstrated full opening capacity of nfxl2-1 stomata. Reduced stomatal opening presumably is a consequence of elevated ABA levels. Furthermore, seedling growth, root growth, and stomatal closure were hypersensitive to exogenous ABA. The enhanced ABA responses may contribute to the improved drought stress resistance of the mutant. Three NFXL2 splice variants were cloned and named NFXL2-78, NFXL2-97, and NFXL2-100 according to the molecular weight of the putative proteins. Translational fusions to the green fluorescent protein suggest nuclear localisation of the NFXL2 proteins. Stable expression of the NFXL2-78 splice variant in nfxl2-1 plants largely complemented the mutant phenotype. Our data show that NFXL2 controls ABA levels and suppresses ABA responses. NFXL2 may prevent unnecessary and costly stress adaptation under favourable conditions. Y1 - 2011 U6 - https://doi.org/10.1371/journal.pone.0026982 SN - 1932-6203 VL - 6 IS - 11 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Caliendo, Marco A1 - Fedorets, Alexandra A1 - Preuss, Malte A1 - Schröder, Carsten A1 - Wittbrodt, Linda T1 - The short- and medium-term distributional effects of the German minimum wage reform JF - Empirical economics N2 - This study quantifies the distributional effects of the minimum wage introduced in Germany in 2015. Using detailed Socio-Economic Panel survey data, we assess changes in the hourly wages, working hours, and monthly wages of employees who were entitled to be paid the minimum wage. We employ a difference-in-differences analysis, exploiting regional variation in the “bite” of the minimum wage. At the bottom of the hourly wage distribution, we document wage growth of 9% in the short term and 21% in the medium term. At the same time, we find a reduction in working hours, such that the increase in hourly wages does not lead to a subortionate increase in monthly wages. We conclude that working hours adjustments play an important role in the distributional effects of minimum wages. KW - minimum wage KW - wage distribution KW - hourly wages KW - inequality Y1 - 2022 U6 - https://doi.org/10.1007/s00181-022-02288-4 SN - 0377-7332 SN - 1435-8921 VL - 64 SP - 1149 EP - 1175 PB - Springer CY - Berlin ER - TY - JOUR A1 - Caliendo, Marco A1 - Fedorets, Alexandra A1 - Preuss, Malte A1 - Schröder, Carsten A1 - Wittbrodt, Linda T1 - The short-run employment effects of the German minimum wage reform JF - Labour economics : an international journal N2 - We assess the short-term employment effects of the introduction of a national statutory minimum wage in Germany in 2015. For this purpose, we exploit variation in the regional treatment intensity, assuming that the stronger a minimum wage ‘bites’ into the regional wage distribution, the stronger the regional labour market will be affected. In contrast to previous studies, we construct two regional bite indicators based upon detailed individual wage data from the Structure of Earnings Survey (SES) 2014 and combine it with administrative information on regional employment. Moreover, using the Socio-Economic Panel (SOEP), we are able to affirm the absence of anticipation effects and verify the assumption of a common trend in wages before the reform. In sum, we find only moderate negative effects on overall employment of about 140,000 (0.4%) jobs, which are mainly driven by a sharp decline of marginal employment (‘mini-jobs’), while we do not find pronounced significant effects for regular employment in most specifications. Our results are robust to a variety of sensitivity tests. KW - Minimum wage KW - Regional bite KW - Employment effects Y1 - 2018 U6 - https://doi.org/10.1016/j.labeco.2018.07.002 SN - 0927-5371 SN - 1879-1034 VL - 53 SP - 46 EP - 62 PB - Elsevier CY - Amsterdam ER -