TY - JOUR A1 - Pilling, Eric A1 - Bähr, Martin A1 - Wunderlich, Ralf T1 - Reinforcement learning methods for the stochastic optimal control of an industrial power-to-heat system JF - Energies N2 - The optimal control of sustainable energy supply systems, including renewable energies and energy storage, takes a central role in the decarbonization of industrial systems. However, the use of fluctuating renewable energies leads to fluctuations in energy generation and requires a suitable control strategy for the complex systems in order to ensure energy supply. In this paper, we consider an electrified power-to-heat system which is designed to supply heat in the form of superheated steam for industrial processes. The system consists of a high-temperature heat pump for heat supply, a wind turbine for power generation, a sensible thermal energy storage for storing excess heat, and a steam generator for providing steam. If the system’s energy demand cannot be covered by electricity from the wind turbine, additional electricity must be purchased from the power grid. For this system, we investigate the cost-optimal operation, aiming to minimize the electricity cost from the grid by a suitable system control depending on the available wind power and the amount of stored thermal energy. This is a decision-making problem under uncertainty regarding the future prices for electricity from the grid and the future generation of wind power. The resulting stochastic optimal control problem is treated as finite-horizon Markov decision process for a multi-dimensional controlled state process. We first consider the classical backward recursion technique for solving the associated dynamic programming equation for the value function and compute the optimal decision rule. Since that approach suffers from the curse of dimensionality, we also apply reinforcement learning techniques, namely Q-learning, that are able to provide a good approximate solution to the optimization problem within reasonable time. KW - Stochastic optimal control KW - Markov decision process KW - Dynamic programming KW - Q-learning KW - Power-to-heat system Y1 - 2026 U6 - https://doi.org/10.3390/en19041046 SN - 1996-1073 VL - 19 IS - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Djoudi, El Aziz A1 - Amossé, Ewen A1 - Aviron, Stéphanie A1 - Birkhofer, Klaus A1 - Libereau, Benjamin A1 - Plantegenest, Manuel A1 - Pétillon, Julien T1 - Multi‑trophic arthropod communities modulated by local farming system and landscape heterogeneity JF - Landscape Ecology N2 - Organic farming is increasingly used worldwide in recent decades, but the role of this farming system in shaping the trophic structure of arthropod communities remains poorly understood, especially at different spatial scales. Therefore, the contribution of landscape heterogeneity in shaping arthropod’s trophic guilds remain understudied. In this study, we assessed how the evenness, the abundance and the taxonomic richness of arthropod trophic groups were shaped by the local farming system, landscape heterogeneity (including the percentage of semi-natural habitats and organic fields), and their interaction. Arthropod’s trophic guilds (ground and vegetation-dwelling) were sampled in 20 spatial independent pairs of conventional (CF) and organic (OF) fields located in Brittany (Western France) by using pitfall traps and sweep nets replicated in time and space. A total of 95,822 arthropods belonging to 197 taxonomic groups were sampled. Farming system has a strong overall positive effect on the community structure of both ground- and vegetation-dwelling arthropods. Landscape heterogeneity, alone and in interaction with farming systems, affected positively the diversity and abundance of most trophic groups for both ground- and vegetation-dwelling arthropods. Organic farming therefore affected the trophic composition of arthropod communities not only locally, but also at the landscape scale. Our study highlights the strong positive effect of farming system and the landscape heterogeneity on arthropod communities and more importantly the interconnection between different spatial scales in this process. Taking these aspects into account is therefore crucial in understanding arthropod community dynamics in agroecosystems. KW - Agroecology KW - Agricultural geography KW - Biodiversity KW - Landscape ecology KW - Organic farming Y1 - 2026 U6 - https://doi.org/10.1007/s10980-026-02298-y SN - 1572-9761 VL - 41 PB - Springer Nature CY - Berlin ER - TY - THES A1 - Menares Barraza, Esteban Javier T1 - Beyond species richness : integrating ecological interactions and multiple goals in grassland conservation T1 - Über die Artenvielfalt hinaus : Integration ökologischer Wechselwirkungen und multipler Zielsetzungen im Grünlandschutz N2 - This thesis explores how incorporating trophic interactions and a wider range of conservation goals can enhance the design and implementation of biodiversity conservation measures in permanent grasslands. Based on data from two long-term biodiversity monitoring regions in Germany [Schwäbische Alb (ALB) and Schorfheide-Chorin (SCH)], the thesis is structured around three main chapters. Together, these chapters examine (1) the reliability of co-occurrence methods for inferring plant–butterfly interactions, (2) the cost-effectiveness of different land-use management practices for achieving multiple conservation goals, and (3) the detection of ecological thresholds for key drivers of change in these goals at species, community, and ecosystem levels. I employed a combination of literature review, field data, statistical inference models, optimisation algorithms, and multivariate analyses to provide a thorough evaluation of grassland biodiversity and move beyond traditional species richness metrics by incorporating interaction networks and other metrics, thus capturing ecological complexity relevant to conservation planning. Chapter I shows that, despite the Relative Interaction Intensity (RII) with pairwise null models approach performing better than the other methods tested, co-occurrence methods fail to reliably predict known plant–butterfly interactions. This highlights the limited usefulness of such methods for mobile species and the importance of directly observing trophic interactions. Chapter II shows that optimising land-use management for multiple conservation goals under cost-effectiveness can achieve substantial ecological benefits (up to 80% of the maximum) using as little as 30% of the budget. Although trade-offs were observed, certain goals, including trophic interactions, butterfly richness, and network nestedness, showed more synergies. Optimising for sets of goals consistently outperformed single-goal strategies, though regional variation in optimal management highlights the need for region-specific planning. Chapter III presents ecological thresholds for key biodiversity goals along management and landscape gradients. In ALB, most goals showed sharp declines above one to two cuts per year, and low grazing levels were associated with higher multidiversity and more complex interaction networks. In SCH, network connectance and the number of interactions increased even at low levels of forest cover (2–10%), highlighting the importance of maintaining forest patches near grasslands for supporting biodiversity. Additionally, even low fertiliser inputs were associated with species-poor butterfly communities composed mainly of common species with wider distribution ranges. These results provide key insights for improving region-specific management strategies in conservation programmes and show the importance of using multiple conservation goals, especially those capturing species interactions, when designing effective conservation strategies. N2 - Diese Dissertation untersucht, wie die Einbeziehung trophischer Interaktionen und erweiterten Schutzzielen die Gestaltung und Umsetzung von Maßnahmen zur Erhaltung der Biodiversität in Dauergrünland verbessern kann. Auf Basis von Daten aus zwei langfristigen Biodiversitäts­Monitoring­Regionen in Deutschland – der Schwäbischen Alb (ALB) und der Schorfheide-Chorin (SCH) – ist die Arbeit in drei Hauptkapitel gegliedert. Diese behandeln (1) die Zuverlässigkeit von Kookkurrenzmethoden zur Ableitung von Pflanze-Schmetterling-Interaktionen, (2) die Kosteneffektivität unterschiedlicher Bewirtschaftungs­praktiken bei mehreren Schutzzielen und (3) ökologische Schwellenwerte zentraler Einflussfaktoren auf Arten-, Gemeinschafts- und Ökosystemebene. Zur umfassenden Bewertung der Grünlandbiodiversität wurden Literaturauswertung, Felddaten, statistische Inferenzmodelle, Optimierungs­algorithmen und multivariate Analysen kombiniert. So wird über klassische Maße wie Artenvielfalt hinausgegangen, indem Interaktionsnetzwerke und weitere Kennzahlen einbezogen werden, um ökologische Komplexität für die Naturschutzplanung adäquater zu erfassen. Kapitel I zeigt, dass die Methode der Relativen Interaktionsintensität (RII) mit paarweisen Nullmodellen bessere Ergebnisse liefert als andere Ansätze, Kookkurrenzmethoden bekannte Pflanze-Schmetterling-Interaktionen jedoch nicht verlässlich vorhersagen können. Dies verdeutlicht die begrenzte Aussagekraft solcher Verfahren für mobile Arten und betont die Bedeutung direkter Beobachtungen trophischer Beziehungen. Kapitel II belegt, dass eine auf Kosteneffektivität beruhende Optimierung der Bewirtschaftung erhebliche ökologische Vorteile bringt – bis zu 80 % des Maximums mit nur 30 % des Budgets. Trotz Zielkonflikten zeigten mehrere Ziele, darunter trophischer Interaktionen, Schmetterlingsvielfalt und Netzwerk-Nestedness, deutliche Synergien. Das Optimieren von Zielkombinationen übertraf stets Einzelfokusstrategien, wobei regionale Unterschiede im optimalen Management die Notwendigkeit regionsspezifischer Planung betonen. Kapitel III präsentiert ökologische Schwellenwerte für zentrale Biodiversitätsziele entlang von Bewirtschaftungs- und Landschaftsgradienten. In der ALB traten starke Rückgänge oberhalb von ein bis zwei Schnitten pro Jahr auf, während geringe Beweidung mit höherer Multidiversität und komplexeren Netzwerken verbunden war. In der SCH stiegen Netzwerkverbundenheit und Interaktionszahl schon bei geringem Waldanteil (2–10 %), was die Bedeutung von Waldflächen nahe Grünland für die Biodiversität unterstreicht. Selbst geringe Düngergaben führten zu schmetterlingsarmen Gemeinschaften, die überwiegend aus häufigen, weit verbreiteten Arten bestanden. Diese Ergebnisse liefern wesentliche Erkenntnisse für die Verbesserung regionsspezifischer Managementstrategien und zeigen die Bedeutung mehrerer Schutzziele – insbesondere solcher, die Arteninteraktionen erfassen – für wirksame Naturschutzstrategien. KW - Co-occurrence analysis KW - Trophic interactions KW - Network metrics KW - Cost-effective optimisation KW - Trade-off analysis KW - Kookkurrenzanalyse <Ökologie> KW - Trophische Interaktionen KW - Netzwerkkennzahlen KW - Kosteneffektive Optimierung KW - Trade-off-Analyse KW - Biodiversität KW - Naturschutzmonitoring KW - Effizienz KW - Artengruppe KW - Nahrungskette KW - Schmetterlinge Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-72336 ER - TY - JOUR A1 - Mbuya, Christel Olivier Lenge A1 - Pawar, Kunal A1 - Jafari, Mitra A1 - Shafiee, Parisa A1 - Okoye Chine, Chike George A1 - Tarifa, Pilar A1 - Dorneanu, Bogdan A1 - Arellano-Garcia, Harvey T1 - Tuning catalyst performance in methane dry reforming via microwave irradiation of nickel-silicon carbide systems JF - Journal of CO2 Utilization N2 - The dry reforming of methane (DRM) is a promising route for converting greenhouse gases such as methane (CH4) and carbon dioxide (CO2) into valuable syngas, hydrogen (H2) and carbon monoxide (CO). However, traditional nickel (Ni)-based catalysts suffer from rapid deactivation due to carbon deposition and sintering, especially when supported on low thermal conductivity materials. In this work, a novel post-synthesis microwave irradiation (MIR) treatment is introduced to systematically optimize the performance of Ni – β – SiC and Ni – Ti – Cβ – SiC catalysts for DRM. Unlike previous studies that have used MIR during reaction or with different supports, this approach tunes the metal – support interactions and textural properties of Ni – β – SiC and Ni – Ti – Cβ – SiC catalysts by varying the MIR exposure time after catalyst synthesis. MIR post-treatment (10–25 s) increased the CH4 conversion to 65 % and the CO2 conversions to 62 % for Ni–β–SiC catalysts and improved the H₂/CO ratio to 0.80, with stable performance over 20 h. For Ni–Ti–Cβ–SiC, MIR (10–20 s) maintained CH4 conversion up to 60 % and CO2 conversion to 58 % over 20 h, while the untreated catalyst, though initially higher, deactivated rapidly. Excessive MIR (30 s) reduced performance for both catalyst types, underscoring the need for optimal exposure time. These findings demonstrate post-synthesis MIR provides a tuneable approach for enhancing both the activity and durability of Ni/SiC – based DRM catalysts through controlled modification of metal – support interactions. This work offers new insights for the design of robust catalysts aimed at greenhouse gas utilization and sustainable syngas production, with activity and stability enhancements linked to controlled changes in metal – support interactions. KW - Carbon dioxide KW - Dry reforming KW - Methane KW - Microwave irradiation KW - Ni Silicon carbide catalysts Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-72832 SN - 2212-9820 VL - 102 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Sharma, Dikshant A1 - Radomsky, Lukas A1 - Mathiazhagan, Akilan A1 - Asli, Majid A1 - Höschler, Klaus A1 - Mallwitz, Regine T1 - Thermal analysis of metal foam integrated heatsink for electrified aircraft applications JF - International Journal of Thermofluids N2 - Metal foams facilitate large heat dissipation in high-power dense systems such as power electronics for electrified propulsion application. This work addresses the cooling of a power semiconductor device with aluminium and copper metal foam integrated hybrid heatsink and its comparative analysis to a conventional finned heatsink using 0D and 3D modelling approach. Two-equation foam model in Fluent is utilized and the numerical approach is validated against experimental dataset. Inlet air velocity is varied such that the Darcy to turbulent regimes of the open-cellular foams are covered. Foam porosities from ∼ 0.85−0.95 with 10–20 PPI are investigated and the thermal performance of the heatsink is found to be independent of the foam material. High porosity (> 0.9), 20 PPI foams are found to aid forced-convection by improving the thermal resistance by more than 10% against the 10 PPI counterparts. The hybrid heatsink outperforms the foam-based and conventional heatsink by 40% and 15% respectively when considering the reduction in junction temperatures, while the hydraulic resistance increases 10 times when compared to the conventional one. The 0D thermal resistance model is robust in predicting the junction temperatures for metal foam heatsinks with only a 5%–6% discrepancy for both the 50 W and 100 W heat load scenarios. The key and novel contribution of this study is the integration of detailed 3D simulations of a power electronics cooling environment with the development of a corresponding 0D thermal model. This approach not only eases the physical representation of the system but also enables the model to be extended to diverse heat load conditions. KW - Electric propulsion KW - Electronics thermal management KW - Metal foam heatsink KW - Porous media KW - Forced convection Y1 - 2025 U6 - https://doi.org/10.1016/j.ijft.2025.101465 SN - 2666-2027 VL - 30 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Yang, Yinghui A1 - Henke, Markus A1 - Möhlenkamp, Georg T1 - Analytical investigation of short-circuit protection and post-fault operation in dual three-phase PMSMs for hybrid electric counter-rotating compressor applications JF - IEEE Access N2 - The hybrid electric counter-rotating compressor (CRC) has the potential to improve power-specific fuel consumption in aircraft engines. However, due to its cascaded structure, a reduction or loss of driving power in a single compressor stage can significantly degrade the overall compressor performance. A short-circuit fault is a typical electrical failure in an electric motor that can lead to a complete loss of driving power. One innovative post-fault operation strategy is to utilize the braking capability of the failed motor at low speed to lock its corresponding compressor stage. In this way, the failed stage can function as a stator stage, still providing degraded flow-guiding capability and preventing reverse rotation. This article investigates the short-circuit protection strategy and post-fault operation of dual three-phase permanent magnet synchronous motors (DTP-PMSMs) for hybrid electric CRC applications. Analytical models are developed to characterize the post-fault behavior of the DTP-PMSM. Key design factors are defined, and their influence on post-fault performance is analyzed. Critical post-fault operating points are identified to evaluate and compare different protection strategies. Based on these results, an optimized shortcircuit protection strategy is proposed for DTP-PMSMs in CRC applications. Finally, the analytical findings and the proposed strategy are validated through simulation. KW - Windings KW - Circuit faults KW - Rotors KW - Torque KW - Protection Y1 - 2025 U6 - https://doi.org/10.1109/ACCESS.2026.3658195 SN - 2169-3536 VL - 14 SP - 17303 EP - 17323 PB - IEEE CY - New York ER - TY - THES A1 - Schiller, Josepha T1 - Explainable artificial intelligence for understanding cross-scale diversification in agricultural landscapes T1 - Erklärbare künstliche Intelligenz zum Verständnis der skalenübergreifenden Diversifizierung in Agrarlandschaften N2 - Agricultural production is expected to cope with numerous challenges in the future. Therefore, the diversification of agricultural systems has gained attention as a promising solution to meet ecological, economic, and social needs in the long term. Despite the overall positive reports of diversification effects, the joint distribution of temporal and spatial diversity and their influencing factors remains largely unexplored. This thesis aims to assess the interrelations of diversity within the agricultural system at the field, farm, and landscape levels and to investigate the links between temporal and spatial crop diversity in Brandenburg, Germany, from 2011 to 2020 using machine learning (ML) combined with explainable artificial intelligence (XAI) tools. This approach involves identifying influencing factors of agricultural diversity such as farm attributes, landscape complexity, and environmental conditions. Data on agricultural land use were derived from the Integrated Administration and Control System (IACS), covering more than 5,642 farms and over 150,000 fields annually. The results revealed (1) a negative relationship between temporal crop diversity at the field level and landscape level complexity associated with soil quality and (2) a positive link between temporal and spatial crop diversity associated with higher crop diversity at the farm level. The potential of using XAI as a trust-enhancing tool for machine learning in such an interdisciplinary research setting was explored by reviewing the recent use of XAI tools in environmental and Earth system sciences in 575 studies. This revealed (3) that despite the increasing use of XAI tools in the environmental and Earth system sciences over time, the question of whether XAI can contribute to increased trust, e.g., in high-stakes decision contexts, has been addressed in only 1.2% of the studies. These findings contribute to understanding synergies and trade-offs between diversity within agricultural systems across levels and scales and its influencing factors. They also provide insights into the potential of XAI tools toward trustworthy ML applications. These findings can serve to develop targeted diversification strategies that enhance the resilience of agricultural systems and the sustainability of agricultural landscapes and improve the trustworthiness of ML and XAI in interdisciplinary research settings. N2 - Die Agrarproduktion wird in Zukunft voraussichtlich zahlreichen Herausforderungen gegenüberstehen. Daher hat die Diversifizierung landwirtschaftlicher Systeme als vielversprechende Lösung an Bedeutung gewonnen, um langfristig ökologische, ökonomische und soziale Bedürfnisse zu erfüllen. Trotz der überwiegend positiven Berichte über die Effekte der Diversifizierung bleibt die gemeinsame Verteilung von zeitlicher und räumlicher Diversität sowie deren Einflussfaktoren weitgehend unerforscht. Die Dissertation zielt darauf ab, die Zusammenhänge von Diversität innerhalb des Agrarsystems auf Feld-, Betriebs- und Landschaftsebene zu analysieren und die Verknüpfungen zwischen zeitlicher und räumlicher Feldfruchtdiversität in Brandenburg, Deutschland, im Zeitraum von 2011 bis 2020 unter Einsatz von Methoden des maschinellen Lernens (ML) in Kombination mit Methoden aus der interpretierbaren künstlichen Intelligenz (XAI) zu untersuchen. Dieser Ansatz beinhaltet die Identifizierung von Einflussfaktoren auf die landwirtschaftliche Diversität, wie zum Beispiel Betriebseigenschaften, Landschaftskomplexität und Umweltbedingungen. Die Daten zur landwirtschaftlichen Flächennutzung wurden aus dem Integrierten Verwaltungs- und Kontrollsystem (InVeKoS) bezogen und umfassen jährlich mehr als 5.642 Betriebe und über 150.000 Felder. Die Ergebnisse zeigten (1) einen negativen Zusammenhang zwischen der zeitlichen Feldfruchtdiversität auf Feldebene und der Landschaftskomplexität, der mit der Bodenqualität assoziiert ist und (2) einen positiven Zusammenhang zwischen zeitlicher und räumlicher Feldfruchtdiversität, der mit einer höheren Feldfruchtdiversität auf Betriebsebene einhergeht. Das Potenzial, XAI als vertrauensbildendes Werkzeug für maschinelles Lernen in einem solchen interdisziplinären Forschungsumfeld einzusetzen, wurde durch die Auswertung der jüngsten Nutzung von XAI-Tools in den Umwelt- und Erdsystemwissenschaften in 575 Studien untersucht. Dabei wurde (3) festgestellt, dass, trotz der zunehmenden Verwendung von XAI-Methoden in diesen Disziplinen, die Frage, ob XAI zu einem erhöhten Vertrauen, beispielsweise in Hochrisikokontexten, beitragen kann, in lediglich 1,2 % der Studien behandelt wurde. Die Ergebnisse helfen beim Verständnis von Synergien und Zielkonflikten von Diversität innerhalb landwirtschaftlicher Systeme auf verschiedenen Ebenen und Skalen sowie deren Einflussfaktoren und liefern Einblicke in das Potenzial von XAI-Methoden für vertrauenswürdige ML-Anwendungen. Diese Erkenntnisse können dazu genutzt werden, gezielte Diversifizierungsstrategien zu entwickeln, die Resilienz in landwirtschaftlichen Systemen und Nachhaltigkeit von Agrarlandschaften stärken und das Vertrauen in ML- und XAI-Anwendungen in interdisziplinären Forschungsumgebungen verbessern. KW - Explainable artificial intelligence KW - Machine learning KW - Agricultural landscapes KW - Crop diversification KW - Heterogeneous landscapes KW - Erklärbare künstliche Intelligenz KW - Maschinelles Lernen KW - Kulturpflanzenvielfalt KW - Landschaftsheterogenität KW - Agrarlandschaften KW - Agrarlandschaft KW - Kulturpflanzen KW - Diversifikation KW - Landschaftsökologie KW - Maschinelles Lernen KW - Erklärbare künstliche Intelligenz Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-72457 ER - TY - JOUR A1 - Julia, Zscherneck A1 - Julia, Binder A1 - Tobias, Mettenberger T1 - Rural network assemblages : disentangling egocentric networks of digital pioneers in peripheral German regions JF - Regional studies, regional science N2 - Digital solutions are seen as promising ways of addressing current challenges in rural regions. Individual or group key actors accessing resources foster these developments through networks. In light of regional clustering and agglomeration effects on the one hand and increased virtual mobility on the other hand, assumptions about the spatiality of such networks are highly controversial. Our paper takes this as a point of departure, asking how spatiality is constructed in the networks of so-called ‘digital pioneers’ (DPs). The sampling process took place in two German rural regions with different preconditions for digital technology adoption, where we conducted egocentric network analysis and qualitative interviews. Employing the assemblage perspective, we analysed networks of 30 individuals in terms of the analytical categories of territoriality, stability and connectivity. Our findings distinguish between three important roles of network contacts: (1) multipliers in social networking, (2) users of the DP’s products and services, as well as (3) close family members that are important in professional contexts. Although DPs are often deeply embedded in and feel attached to their region, networks vary significantly in their territorial radius, also including highly functional problem-solving contacts to distant places. Consequently, our evidence challenges static territorial models of innovation processes, advocating for processual and multidimensional perspectives that consider social networks and individual agency. Likewise, our study complements current research on rural governance by shifting the focus from key institutions and formal networks to less formally integrated actors and problem-solving networks. KW - Qualitative network analysis KW - Assemblage KW - Bridging and bonding ties KW - Peripheral regions Germany Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-72787 SN - 2168-1376 VL - 12 IS - 1 SP - 996 EP - 1012 PB - Routledge CY - London ER - TY - THES A1 - Agunbiade, Michael Bode T1 - Human perceptions, ecological role and threats to the hooded vultures (𝘕𝘦𝘤𝘳𝘰𝘴𝘺𝘳𝘵𝘦𝘴 𝘮𝘰𝘯𝘢𝘤𝘩𝘶𝘴) in the Gambia : conservation implications T1 - Menschliche Wahrnehmung, ökologische Rolle und Bedrohung des Kappengeiers (𝘕𝘦𝘤𝘳𝘰𝘴𝘺𝘳𝘵𝘦𝘴 𝘮𝘰𝘯𝘢𝘤𝘩𝘶𝘴) in Gambia : Auswirkungen auf die Erhaltung N2 - Hooded Vultures (Necrosyrtes monachus) are critically endangered urban scavengers that are declining rapidly across West Africa due to poisoning, habitat destruction, and belief-based exploitation. In cities and towns, they provide vital ecosystem services by removing organic waste, limiting pest outbreaks, and reducing disease risks. Despite their importance, their populations and habitats remain undervalued and insufficiently protected in many regions, including The Gambia. Conservation planning is further constrained by limited quantitative information on (i) belief-based use of vultures, (ii) the influence of organic waste availability on scavenger community composition at slaughterhouses, and (iii) local perceptions and attitudes toward vulture conservation. This thesis assesses ecosystem services provided by Hooded Vultures in The Gambia, focusing on their role in urban organic waste removal, while identifying threats and proposing strategies for effective conservation. Specifically, it (1) investigates belief-based use of vultures in West Africa, (2) maps suitable habitats in The Gambia, (3) evaluates how organic waste availability shapes scavenger communities and interactions at slaughterhouses, and (4) examines community perceptions and perceived threats. A systematic review of 92 studies demonstrates that belief-based use is a major driver of vulture mortality in West Africa, contributing up to 29% of documented deaths, with Hooded Vultures disproportionately affected and comprising over 90% of trafficked parts in some areas. Poisoning, both intentional and accidental, is the primary method of killing, and increasing demand has raised the cost of vulture parts, further incentivizing exploitation. Habitat suitability modeling using MaxEnt and road surveys (791 km, 2017–2021) indicates that only 11.6% of The Gambia represents highly suitable habitat, concentrated mainly in the western region and Greater Banjul, where food resources associated with human settlements are abundant. Built-up area density, proximity to roads, and water availability explain most variation in occurrence. Surveys of five slaughterhouses reveal that Hooded Vultures dominate where organic waste is highest, confirming their ecological role, although domestic dogs frequently outcompete them during direct interactions. Finally, questionnaires from 200 respondents show predominantly positive attitudes (74%) and recognition of the species’ benefits, while highlighting poisoning, habitat loss, and belief-based use as key threats and revealing limited awareness of conservation initiatives. Overall, conserving Hooded Vultures in The Gambia requires integrated actions combining habitat protection, waste management, poisoning prevention, and community engagement to safeguard both biodiversity and essential ecosystem services. N2 - Kappengeier (Necrosyrtes monachus) sind kritisch gefährdete Aasfresser, deren Bestände in Westafrika aufgrund von Vergiftung, Lebensraumverlust und glaubensbasiertem Gebrauch stark zurückgehen. In urbanen Räumen übernehmen sie zentrale ökologische Funktionen, indem sie organische Abfälle beseitigen, Schädlingspopulationen begrenzen und das Risiko der Krankheitsübertragung reduzieren. Trotz dieser bedeutenden Ökosystemleistungen werden ihre Populationen und geeigneten Lebensräume in vielen Regionen, darunter auch in Gambia, weiterhin unterschätzt und unzureichend geschützt. Zudem erschwert der Mangel an quantitativen Daten zum (i) glaubensbasierten Einsatz von Geiern, (ii) Einfluss der Verfügbarkeit organischer Abfälle auf die Zusammensetzung von Aasfressergemeinschaften an Schlachthöfen sowie (iii) zu lokalen Wahrnehmungen und Einstellungen gegenüber ihrem Schutz eine zielgerichtete Naturschutzplanung. Ziel dieser Dissertation ist es, die von Kappengeier erbrachten Ökosystemleistungen in Gambia – insbesondere ihre Rolle bei der Entsorgung organischer Abfälle in städtischen Gebieten – zu bewerten, Bedrohungen zu identifizieren und wirksame Schutzstrategien abzuleiten. Dazu werden (1) der glaubensbasierte Gebrauch von Geiern in Westafrika untersucht, (2) geeignete Lebensräume in Gambia modelliert, (3) die Auswirkungen der Abfallverfügbarkeit auf Zusammensetzung und Interaktionen von Aasfressergemeinschaften an Schlachthöfen analysiert und (4) Einstellungen sowie Bedrohungswahrnehmungen lokaler Bevölkerungsgruppen erfasst. Eine systematische Literaturübersicht von 92 Studien zeigt, dass der glaubensbasierte Gebrauch eine wesentliche Ursache der Geiersterblichkeit in Westafrika darstellt und bis zu 29% der dokumentierten Todesfälle erklärt. Kappengeier sind dabei überproportional betroffen und machen in einzelnen Regionen mehr als 90% der gehandelten Körperteile aus. Vergiftung – sowohl gezielt als auch unbeabsichtigt – ist die häufigste Tötungsmethode; steigende Nachfrage hat zudem zu höheren Preisen für Geierteile und damit zu zusätzlichem Ausbeutungsdruck geführt. Habitat-Eignungsmodelle (MaxEnt) auf Basis von Straßenerhebungen (791 km, 2017–2021) weisen darauf hin, dass nur 11,6% Gambias hoch geeignet sind, vor allem im Westen und im Großraum Banjul, wo menschliche Siedlungen reichlich Nahrungsquellen bereitstellen. Dichte bebauter Flächen, Straßennähe und Wasserverfügbarkeit erklären den Großteil der räumlichen Variation. Untersuchungen an fünf Schlachthöfen belegen, dass Kappengeier dort dominieren, wo große Mengen organischer Abfälle vorhanden sind, wenngleich Haushunde sie in direkten Konkurrenzsituationen häufig verdrängen. Befragungen von 200 Personen zeigen überwiegend positive Einstellungen (74%) und ein Bewusstsein für den Nutzen der Geier, zugleich werden Vergiftung, Lebensraumverlust und glaubensbasierter Gebrauch als zentrale Bedrohungen genannt und ein geringer Kenntnisstand über bestehende Schutzmaßnahmen sichtbar. Insgesamt erfordert der Schutz der Kappengeier in Gambia einen integrierten Ansatz aus Habitatmanagement, verbesserten Abfallpraktiken, Maßnahmen gegen Vergiftung sowie intensiver Öffentlichkeitsarbeit, um sowohl Biodiversität als auch wichtige Ökosystemleistungen langfristig zu sichern. KW - Urban waste management KW - Conservation strategies KW - Suitable habitats KW - Community perceptions KW - Städtische Abfallwirtschaft KW - Erhaltungsstrategien KW - Geeignete Lebensräume KW - Gemeinschaftswahrnehmungen Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-72705 ER - TY - JOUR A1 - Malk, Konrad A1 - Riedel, Ramona A1 - Hinz, Christoph A1 - Fischer, Thomas A1 - Martienssen, Marion T1 - Adsorption of phosphonates to iron- or aluminum-based flocculants in wastewater treatment JF - Water N2 - In this study, we investigated the impact of varying iron (Fe) and aluminum (Al) contents on the adsorption of phosphonates to activated sludge. Phosphonates originating from household applications account for up to 40% of the non-reactive dissolved phosphorus in domestic sewage treatment plants and thus can contribute to the eutrophication of water bodies. Although these substances are not readily degradable, substantial quantities, ranging from 40% to more than 90%, are removed by sludge adsorption. The results demonstrate a strong correlation between the adsorption of aminophosphonates and the Fe3+ content of the sludge. The maximum phosphonate loadings were 5.94 mmol g−1 Fe3+ for ATMP, 4.94 mmol g−1 Fe3+ for EDTMP, 4.74 mmol g−1 Fe3+ for DTPMP, and 2.25 mmol g−1 Fe3+ for glyphosate. In contrast to pure ferric hydride flocs, the adsorption of phosphonates was approximately threefold higher when the hydroxides were located within activated sludge flocs. It is concluded that native sludge flocs provide larger iron surfaces than ferric hydroxide alone. Based on the weight of the adsorbents, aluminum salts were four times less efficient than ferric salts. In sludge without ferric or aluminum hydroxides, phosphonate adsorption was negligible. KW - Adsorption KW - Activated sludge KW - Ferrous oxide KW - Phosphonates KW - Wastewater treatment Y1 - 2025 U6 - https://doi.org/10.3390/w18010116 SN - 2073-4441 VL - 18 IS - 1 PB - MDPI CY - Basel ER -