TY - THES A1 - Hartmann, Anne T1 - Tracing the evolution of hillslope structure and hillslope hydrological response over ten millennia in two glacial forefields of different geology T1 - Nachverfolgung der Evolution von Hangstruktur und hydrologischer Reaktion über zehn Jahrtausende in zwei Gletschervorfeldern N2 - Assessing the impact of global change on hydrological systems is one of the greatest hydrological challenges of our time. Changes in land cover, land use, and climate have an impact on water quantity, quality, and temporal availability. There is a widespread consensus that, given the far-reaching effects of global change, hydrological systems can no longer be viewed as static in their structure; instead, they must be regarded as entire ecosystems, wherein hydrological processes interact and coevolve with biological, geomorphological, and pedological processes. To accurately predict the hydrological response under the impact of global change, it is essential to understand this complex coevolution. The knowledge of how hydrological processes, in particular the formation of subsurface (preferential) flow paths, evolve within this coevolution and how they feed back to the other processes is still very limited due to a lack of observational data. At the hillslope scale, this intertwined system of interactions is known as the hillslope feedback cycle. This thesis aims to enhance our understanding of the hillslope feedback cycle by studying the coevolution of hillslope structure and hillslope hydrological response. Using chronosequences of moraines in two glacial forefields developed from siliceous and calcareous glacial till, the four studies shed light on the complex coevolution of hydrological, biological, and structural hillslope properties, as well as subsurface hydrological flow paths over an evolutionary period of 10 millennia in these two contrasting geologies. The findings indicate that the contrasting properties of siliceous and calcareous parent materials lead to variations in soil structure, permeability, and water storage. As a result, different plant species and vegetation types are favored on siliceous versus calcareous parent material, leading to diverse ecosystems with distinct hydrological dynamics. The siliceous parent material was found to show a higher activity level in driving the coevolution. The soil pH resulting from parent material weathering emerges as a crucial factor, influencing vegetation development, soil formation, and consequently, hydrology. The acidic weathering of the siliceous parent material favored the accumulation of organic matter, increasing the soils’ water storage capacity and attracting acid-loving shrubs, which further promoted organic matter accumulation and ultimately led to podsolization after 10 000 years. Tracer experiments revealed that the subsurface flow path evolution was influenced by soil and vegetation development, and vice versa. Subsurface flow paths changed from vertical, heterogeneous matrix flow to finger-like flow paths over a few hundred years, evolving into macropore flow, water storage, and lateral subsurface flow after several thousand years. The changes in flow paths among younger age classes were driven by weathering processes altering soil structure, as well as by vegetation development and root activity. In the older age class, the transition to more water storage and lateral flow was attributed to substantial organic matter accumulation and ongoing podsolization. The rapid vertical water transport in the finger-like flow paths, along with the conductive sandy material, contributed to podsolization and thus to the shift in the hillslope hydrological response. In contrast, the calcareous site possesses a high pH buffering capacity, creating a neutral to basic environment with relatively low accumulation of dead organic matter, resulting in a lower water storage capacity and the establishment of predominantly grass vegetation. The coevolution was found to be less dynamic over the millennia. Similar to the siliceous site, significant changes in subsurface flow paths occurred between the young age classes. However, unlike the siliceous site, the subsurface flow paths at the calcareous site only altered in shape and not in direction. Tracer experiments showed that flow paths changed from vertical, heterogeneous matrix flow to vertical, finger-like flow paths after a few hundred to thousands of years, which was driven by root activities and weathering processes. Despite having a finer soil texture, water storage at the calcareous site was significantly lower than at the siliceous site, and water transport remained primarily rapid and vertical, contributing to the flourishing of grass vegetation. The studies elucidated that changes in flow paths are predominantly shaped by the characteristics of the parent material and its weathering products, along with their complex interactions with initial water flow paths and vegetation development. Time, on the other hand, was not found to be a primary factor in describing the evolution of the hydrological response. This thesis makes a valuable contribution to closing the gap in the observations of the coevolution of hydrological processes within the hillslope feedback cycle, which is important to improve predictions of hydrological processes in changing landscapes. Furthermore, it emphasizes the importance of interdisciplinary studies in addressing the hydrological challenges arising from global change. N2 - Die Einschätzung der Auswirkungen des globalen Wandels auf die lokale Hydrologie stellt zweifellos eine der bedeutendsten hydrologischen Herausforderungen unserer Zeit dar. Die zuverlässige Vorhersage der zukünftigen Verfügbarkeit, Menge und Qualität des Wassers in Landschaften gewinnt dabei an höchster Bedeutung. Es herrscht weitgehender Konsens darüber, dass hydrologische Systeme aufgrund des globalen Wandels nicht mehr als statische Gebilde betrachtet werden können. Vielmehr sind sie als ganzheitliche Ökosysteme zu verstehen, in denen hydrologische Prozesse mit biologischen, geomorphologischen und pedologischen Faktoren interagieren und sich gemeinsam entwickeln. Allerdings ist das Wissen über die Entwicklung und die Rückkopplung hydrologischer Prozesse, insbesondere im Hinblick auf die Entstehung unterirdischer (präferenzieller) Fließwege, aufgrund mangelnder Beobachtungsdaten noch stark begrenzt. Das Hauptziel dieser Studie liegt daher darin, anhand von Untersuchungen auf der Hangskala die Wechselwirkung zwischen Struktur und hydrologischem Verhalten zu erforschen. Dadurch soll ein besseres Verständnis für den Rückkopplungszyklus gewonnen werden. Die vier in dieser Arbeit präsentierten Studien befassen sich mit der Entwicklung hydrologischer, biologischer und physikalischer Eigenschaften von Hängen sowie der Evolution hydrologischer Fließwege über einen Zeitraum von zehntausend Jahren in zwei unterschiedlichen geologischen Geologien. Durch die Analyse von Moränen-Chronosequenzen in zwei Gletschervorfeldern, die jeweils aus silikatreichem bzw. kalkreichem Geschiebemergel entstanden sind, wird die komplexe Koevolution in Abhängigkeit von der geologischen Beschaffenheit des Ausgangsmaterials beleuchtet. Die Ergebnisse zeigen, dass die verschiedenen Eigenschaften von silikatreichem und kalkhaltigem Ausgangsmaterial unter den gegebenen Klimabedingungen zu Unterschieden in Bodeneigenschaften, Durchlässigkeit und Wasserspeicherung führen. Dies wiederum begünstigt unterschiedliche Vegetationstypen und resultiert in vielfältigen Ökosystemen mit variierenden hydrologischen Dynamiken. Interessanterweise treibt das silikatreiche Ausgangsmaterial die Koevolution stärker an. Hierbei spielt der pH-Wert des Bodens eine Schlüsselrolle, da er Auswirkungen auf Vegetation, Bodenbildung und folglich auch auf die Hydrologie hat. Die saure Verwitterung des silikatreichen Materials begünstigt die Anreicherung organischer Substanz, was zu einer Erhöhung der Wasserspeicherkapazität des Bodens und zur Podsolisierung führt. Innerhalb weniger Jahrhunderte entwickelt sich das unterirdische Wassertransportsystem von einer vertikalen, heterogenen Matrixströmung zu fingerartigen Fließwegen und nach mehreren Jahrtausenden zu einem System aus Makroporen, wobei die Wasserspeicherung und die unterirdische, laterale Strömung überwiegen. Im Gegensatz dazu weist der kalkhaltige Standort eine hohe pH-Pufferkapazität auf. In dem basischen bis neutralen Milieu sammelt sich vergleichsweise wenig abgestorbene, organische Substanz an, was zu einer geringeren Wasserspeicherkapazität führt und die Ansiedlung von Grasvegetation begünstigt. Die Fließwege ändern lediglich ihre Form, nicht jedoch ihre Richtung. Es wurde lediglich ein Übergang von vertikaler, heterogener Matrixströmung zu vertikalen, fingerartigen Fließwegen beobachtet. Der schnelle vertikale Wassertransport mit geringer Speicherung begünstigt die Erhaltung der Grasvegetation. Die durchgeführten Studien verdeutlichen, dass die Entwicklung der Fließwege hauptsächlich von den Eigenschaften des Ausgangsgesteins und seinen Verwitterungsprodukten sowie von deren komplexen Interaktionen mit den ursprünglichen Fließwegen und der Entwicklung der Vegetation geprägt ist. Im Gegensatz dazu spielt die Zeit keine entscheidende Rolle bei der Beschreibung der Evolution der hydrologischen Reaktion. Diese Studie trägt wesentlich dazu bei, die bestehende Lücke in Beobachtungen für die Erforschung der Koevolution von hydrologischen, biologischen, geomorphologischen und pedologischen Prozessen zu schließen. Dies ist von großer Bedeutung, um Vorhersagen hydrologischer Prozesse in sich wandelnden Landschaften zu verbessern. Sie zeigt außerdem die Relevanz interdisziplinärer Studien auf, um den zukünftigen Herausforderungen in der Hydrologie im Zuge des globalen Wandels erfolgreich zu begegnen. KW - soil hydrology KW - chronosequence study KW - landscape evolution KW - Chronosequenzstudie KW - Landschaftsentwicklung KW - Bodenhydrologie Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-628629 ER - TY - JOUR A1 - Lenkeit, Jenny A1 - Hartmann, Anne A1 - Ehlert, Antje A1 - Knigge, Michel A1 - Spörer, Nadine T1 - Effects of special educational needs and socioeconomic status on academic achievement BT - Separate or confounded? JF - International Journal of Educational Research N2 - Germany is continuously expanding its inclusive education system. Research provides evidence that students with special educational needs (SEN) in inclusive school settings show lower academic achievement and come from lower socioeconomic backgrounds than their peers without SEN. Identifying to what extent the disadvantages originating from both characteristics are confounded in predicting academic achievement, has been neglected in the German educational context. Using data of 1711 primary and secondary school students from a longitudinal study in the state of Brandenburg, this study evaluates to what degree SEN (in the areas of learning and emotional-social difficulties) and socioeconomic background (SES) are confounded in predicting academic initial achievement in reading and mathematics as well as their development over time. Using multilevel modelling techniques that nest three measurement points into students and students into classes, results identify SES and SEN as relevant predictors of achievement status and growth in both subjects. Only few and small mediation effects of SES were found, indicating that both SES and SEN remain independent risk factors for achievement. Understanding the origins of student disadvantage can help teachers to make better informed choices for designing support measures and aid policymakers' reasoning for resource allocations. KW - Special educational needs KW - Socioeconomic background KW - Multiple disparities KW - Longitudinal KW - Hierarchical linear modelling Y1 - 2022 U6 - https://doi.org/10.1016/j.ijer.2022.101957 SN - 0883-0355 VL - 113 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Mikolaj, Michal A1 - Güntner, Andreas A1 - Brunini, Claudio A1 - Wziontek, Hartmut A1 - Gende, Mauricio A1 - Schröder, Stephan A1 - Cassino, Augusto M. A1 - Pasquare, Alfredo A1 - Reich, Marvin A1 - Hartmann, Anne A1 - Oreiro, Fernando Ariel A1 - Pendiuk, Jonathan A1 - Guarracino, Luis A1 - Antokoletz, Ezequiel D. T1 - Hydrometeorological and gravity signals at the Argentine-German Geodetic Observatory (AGGO) in La Plata JF - Earth system science data N2 - The Argentine-German Geodetic Observatory (AGGO) is one of the very few sites in the Southern Hemisphere equipped with comprehensive cutting-edge geodetic instrumentation. The employed observation techniques are used for a wide range of geophysical applications. The data set provides gravity time series and selected gravity models together with the hydrometeorological monitoring data of the observatory. These parameters are of great interest to the scientific community, e.g. for achieving accurate realization of terrestrial and celestial reference frames. Moreover, the availability of the hydrometeorological products is beneficial to inhabitants of the region as they allow for monitoring of environmental changes and natural hazards including extreme events. The hydrological data set is composed of time series of groundwater level, modelled and observed soil moisture content, soil temperature, and physical soil properties and aquifer properties. The meteorological time series include air temperature, humidity, pressure, wind speed, solar radiation, precipitation, and derived reference evapotranspiration. These data products are extended by gravity models of hydrological, oceanic, La Plata estuary, and atmospheric effects. The quality of the provided meteorological time series is tested via comparison to the two closest WMO (World Meteorological Organization) sites where data are available only in an inferior temporal resolution. The hydrological series are validated by comparing the respective forward-modelled gravity effects to independent gravity observations reduced up to a signal corresponding to local water storage variation. Most of the time series cover the time span between April 2016 and November 2018 with either no or only few missing data points. The data set is available at https://doi.org/10.588/GFZ.5.4.2018.001 (Mikolaj et al., 2018). Y1 - 2019 U6 - https://doi.org/10.5194/essd-11-1501-2019 SN - 1866-3508 SN - 1866-3516 VL - 11 IS - 4 SP - 1501 EP - 1513 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Spörer, Nadine A1 - Lenkeit, Jenny A1 - Bosse, Stefanie A1 - Hartmann, Anne A1 - Ehlert, Antje A1 - Knigge, Michel T1 - Students’ perspective on inclusion BT - Relations of attitudes towards inclusive education and self-perceptions of peer relations JF - International journal of educational research N2 - The goal of the present study was to analyze how students' attitudes towards inclusive education develop over the course of a school year and how these attitudes relate to students' peer relations. Sixth- and seventh-graders of 44 inclusive classes filled out a questionnaire at two measurement points within one school year to assess attitudes towards inclusive education and peer relations. Applying multilevel regression analyses it turned out that changes in peer relations over time were positively predicted by students' attitudes towards instructional adaptations for students with behaviour difficulties. Further, students with self-perceived behavior difficulties reported lower scores for peer relations compared to students without self-perceived difficulties. Results are discussed with respect to structural factors and individual characteristics affecting inclusive education. KW - peer relations KW - inclusion KW - students KW - attitudes KW - special educational KW - needs Y1 - 2020 U6 - https://doi.org/10.1016/j.ijer.2020.101641 SN - 0883-0355 SN - 2666-3740 VL - 103 PB - Elsevier Science CY - Oxford ER -