Hydrological models can be categorised into three groups: empirical models that are based on simple mathematical functions or being data-driven, conceptual models that rely on abstract combinations of storages and fluxes to depict catchment processes, or physically-based models that are structurally complex and incorporate physical interactions at different scales to simulate processes and system states. To calibrate and evaluate especially physically-based models, the use of multi-criteria evaluation schemes has proven to be effective to find model parameterisations that can reproduce multiple catchment processes and states instead of only the discharge. However, uncertainty in models, originating from different sources, often limits the robust interpretability of simulation results, making it necessary to assess how modelling applications can be improved to reduce uncertainty. In this thesis, the relevance of structural adequacy for the depiction of processes in models was demonstrated for the micro level for the example of dynamic phenology, where spatiotemporal model performance was improved by implementing a dynamic approach to modelling leaf emergence instead of a static one. For model evaluation at macro level, it was shown how a multi-criteria approach combining groundwater dynamics, surface runoff patterns and discharge can identify process-behavioural parameterisations and thus improve process depiction in hydrological models. At the meta level, it was demonstrated how the quasi-coupling of a hydrological and a hydraulic model can combine the different strengths of both models to simulate surface runoff processes taking infiltration into account, whereby the relevance of multi-criteria evaluated hydrological models for the derivation of hydrological variables was shown. In addition, uncertainty was explicitly incorporated into model evaluation at the meta level, where a virtual reality model approach was applied to assess the contribution that different variables can make to model evaluation when the associated measurement uncertainty is taken into account. Based on the individual results, it was possible to conclude that uncertainty and its different sources are a relevant factor in model evaluation at different levels and could be reduced by improving structural model adequacy, adapting model application approaches, and explicitly incorporating uncertainty into model evaluations.

Sea-ice leads play a key role in the climate system by facilitating heat and moisture exchanges between the ocean and atmosphere, as well as by providing essential habitats for marine life. This study presents new insights from a gap-filled monthly dataset on sea-ice leads in the Southern Ocean and a first comprehensive analysis of spatial patterns, seasonal variability, and long-term trends of wintertime (April to September) sea-ice leads over a 21-year period (2003–2023). Our findings reveal that leads are ubiquitous in the Southern Ocean and show distinct spatial patterns with maximum lead frequencies close to the coastline, over the shelf break, and close to seafloor ridges and peaks. We see a strong seasonal variability in lead occurrence, with lead frequencies peaking in mid-winter. Weak but significant trends in lead frequencies are shown for the presented period for individual regions and months. Rather small changes in lead occurrence over the 21 years suggest stable wintertime sea-ice compactness despite the observed strong fluctuations and recent anomalies in sea-ice extent. Expanding upon previous work of lead detection in Antarctic sea ice, this study provides first results on the long-term regional, seasonal, and inter-annual variability of sea-ice leads in the Southern Ocean and can thereby contribute to an improved understanding of air–sea-ice–ocean interactions in the climate system. It also underscores the need for further investigation into the individual contributions of atmospheric and oceanic drivers to sea-ice lead formation in the Antarctic.

This thesis seeks to improve the understanding of evolution and habitat as key factors forming tadpole morphology (i.e. of larvae of the order Anura), uncovers existing gaps in current research and recommends strategies and directions for future research. The present study improves the knowledge about the influences of evolution and habitat on the bauplan of tadpoles in a global scale ensuring maximum standardization and comparability of the data. In relation to the total number of tadpoles assumed to exist, only a small proportion has been described and only a few of them have been identified genetically. The lack of a global standard for their description makes it difficult to compare data. Using the tadpole of a harlequin frog (Atelopus) from Guiana region, it is shown that only an integrative approach with morphological and genetic data can solve taxonomic problems. In the study area of Madagascar, it becomes evident that in this region the common genetic history only has little influence on morphology, in contrast to the aquatic way of life. Tadpoles from flowing waters develop larger eyes, more robust tail muscles and smaller fins to cope better with current conditions and move more efficiently. In an additional study, the examination is extended to an almost global level. To achieve the intended standardization, over 1000 individuals (tadpoles) from 144 species have been examined. It can be shown that the common evolutionary history on a global scale influences morphology as strongly as the habitat. In addition, the influence of specialized nutrition and the climate is investigated.

This thesis examines how Europe sustains its leadership and competitiveness as a global center for foreign direct investment (FDI) and trade between 1991 and 2023. While EU membership historically functioned as the dominant determinant of inward FDI and trade integration, its relative influence has declined as new structural factors, based on trade dynamics and export-platform strategies, have emerged, together with the growing presence of Asian, especially Chinese, investors establishing production hubs in Central and Eastern Europe to serve the wider EU market. Lower trade costs within Europe have reinforced this shift, leading EU investors to focus on vertical FDI, while non-EU investors to adopt export-platform FDI patterns. Chinese investment has moved from infrastructure-focused projects to strategic-sector FDI, highlighting Europe’s exposure to evolving global industrial and geopolitical dynamics. Chapter 2 examines how traditional determinants of FDI, including EU membership, interact with emerging drivers, such as trade interdependence, export-platform strategies, and Asian influence, to shape investment patterns in Europe. It employs a gravity-based empirical framework augmented with newly developed indicators, comprising the Bilateral Trade Interdependence Index, the Export-Platform Indicator, and Belt and Road Initiative (BRI) participation, together with a functional integration approach, covering over 95% of European countries and their global partners from 2010 to 2023. The findings indicate that trade dependency with non-EU partners grew most rapidly, increasing by 55% between 2011 and 2023. Stronger bilateral trade interdependence is found to significantly predict higher FDI inflows. The BRI analysis and functional classification indicate a shift from infrastructure-focused Chinese investment to strategic sectors, including electric vehicles and semiconductors. Since 2018, export-platform strategies have expanded from Europe’s core economies into Central and Eastern Europe, forming emerging production hubs, and have subsequently moved toward the Western Balkans and Turkey, likely reflecting evolving EU regulations and broader supply-chain realignments. Chapter 3 expands the FDI analysis to cover a longer timeframe, from 1991 to 2017, focusing on the period when EU membership exerted a strong influence on FDI in Europe, transforming member countries from primarily cost-attractive destinations into global investment centers. Using an augmented gravity model covering 39 host and origin countries, the analysis finds that EU membership increased FDI inflows by 23%, with investments from core EU members expanding into new EU member states, while FDI from non-EU countries decreased. At the same time, EU membership may also be driven by trade, and EEA participation reflects non-FDI motivations. The chapter also highlights that EU accession strengthens both market-seeking (horizontal) and efficiency-seeking (vertical) FDI motives and applies methods to address negative and zero FDI values issues, ensuring robust estimation. The inclusion of lagged and lead variables shows that the EU integration process is phased over time, affecting FDI inflows with lags of up to 10–15 years after accession. Chapter 4 expands the range of FDI determinants by deriving trade cost indices as a proxy for connectivity and extending the geographic scope of the analysis. In addition to EU members, the sample includes the Western Balkans, Turkey, and new EU candidates and applicants (Moldova, Ukraine, and Georgia) over the period 2000 to 2020, covering approximately 80% of European FDI flows. Trade costs are calculated for each country in the sample with its trade partners, not only within and between European subregions but also with non-EU partners such as China, and are combined with measures of FDI restrictiveness. The results show that China remains among the EU’s top three trading partners in goods and that trade costs significantly influence FDI inflows in Europe. The analysis also highlights that declining trade costs between European countries have reduced market-seeking (horizontal) FDI, while non-European investors, especially China, increasingly pursue export-platform FDI to serve third-country markets. A sharp reduction in trade costs between the Western Balkans and the EU (-45%) and a smaller decline with China (-35%) illustrates how regional integration reduces the need for local horizontal FDI while reinforcing Europe’s role as a hub for global production. Chapter 5 shows that despite concerns about increasing outside influence, developed European countries remain the dominant source of FDI in the region. The chapter focuses on China’s role, examining FDI patterns across advanced EU members, new member states, and Western Balkan economies between 2000 and 2019, while distinguishing the effects of EU integration and BRI participation on FDI. Chinese influence has expanded primarily through the Belt and Road Initiative, particularly in accession and neighboring countries. Although BRI participation does not significantly increase FDI on its own, reflecting the dominant part of loan-financed infrastructure rather than private investment, it has strengthened physical and digital connectivity, laying the groundwork for future, longer-term FDI. The analysis also shows that intra-EU trade costs declined significantly after the 2004 and 2007 enlargements, while trade costs between the Western Balkans and China have fallen steadily since the launch of the BRI in 2013. As a result, Chinese influence is more pronounced in new EU member states and Western Balkan economies than in Western Europe. Over time, enhanced connectivity and supply-chain integration may support more diversified FDI inflows.

Die vorliegende Dissertation untersucht das Motiv der Freiheit als zentrales Thema in Werken des DDR-Autors Ulrich Plenzdorf. Ziel ist es, Plenzdorfs literarische Auseinandersetzung mit individuellen Freiheitsbestrebungen unter den Bedingungen der SED-Diktatur eingehend zu erschließen. Die Analyse erfolgt diachron und umfasst Texte aus den 1960er Jahren bis zum Ende der 1980er Jahre, wodurch Entwicklungslinien, thematische Verschiebungen und ästhetische Veränderungen im Werk sichtbar werden. Neben kanonisierten Werken werden auch bislang wenig beachtete Texte einbezogen, um ein vollständigeres Bild von Plenzdorfs literarischer Produktion zu gewinnen und Forschungslücken zu schließen. Methodisch orientiert sich die Studie an einem kulturwissenschaftlichen Ansatz im Sinne des New Historicism, der literarische Texte als Teil kultureller Praktiken und sozialer Machtverhältnisse versteht. Vor diesem Hintergrund wird gezeigt, wie Plenzdorf Freiheitsvorstellungen in unterschiedlichen historischen Phasen der DDR artikuliert und mit Alltagskultur, Subkulturen sowie gesellschaftlichen Konfliktfeldern verknüpft. Diese Dissertation leistet damit einerseits einen Beitrag zur Neubewertung Plenzdorfs und andererseits zur kulturhistorischen Kontextualisierung der DDR-Literatur.