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Item Analyzing the inclusion of nature in an oil palm plantation: a landscape ecological case study in Mapiripán, Meta, Colombia(2021) Gómez Mateus, Adriana Marcela; Waldhardt, Rainer; Nuppenau, Ernst-AugustOil palm plantations are known for their adverse effects on biodiversity and human well-being. Such industrial agricultural landscapes are homogeneous and oversimplify biodiversity and convey little or no human well-being. Yet, an oil palm plantation design implementing land sharing and land sparing simultaneously can provide a place for biodiversity conservation, generate social landscape values and provide human well-being. Also, local biodiversity controls agricultural pests. An Integration of nature in an oil palm plantation can foresee benefits and risks to the oil palm and workers. First, a heterogeneous agricultural landscape can provide habitat to local species, which can act as a biological control in agricultural systems. Second, it can provide social landscape values and change and shape humans’ perception of the plantation. Third, workers are positively or negatively affected by interacting with nature inside the plantation. Intensive large-scale agricultural landscapes such as plantations are often considered and designed as sole production areas. They can also exhibit a complex spatial pattern of vegetation types, implementing land sparing and land sharing approaches. The company, Poligrow Colombia SAS, has implemented these approaches in the Macondo plantation for a decade. The company followed the principles and criteria of the RSPO and the Rainforest Alliance plus the national laws to design the oil palm plantation. As a result, the plantation has different vegetation types besides oil palms, namely compositional and configuration heterogeneity. The Macondo plantation has gained a nature-enhanced agricultural landscape that can create different habitats for local flora and fauna and provide ecological and social values. For instance, biological control service for oil palms pests of Opsiphanes cassina and Rhynchophorus palmarum. Also, workers can perceive social landscape values such as shade and water provision. A nature-enhanced plantation design is possible to implement and maintain, though it generates costs. Yet, implementing both approaches provides a framework to make large-scale farming systems more sustainable. It is possible to argue that nature-enhanced plantation design is more sustainable as compared to monocultures. Other oil palm plantations and other large-agricultural systems can see the Macondo plantation design as viable. Production areas and conservation areas, with native flora and fauna, are intertwined. However, it is still unknown whether implementing both approaches simultaneously in an oil palm plantation can bring any benefits to the agricultural landscape structure, provision of social landscape values and human wellbeing. This interdisciplinary study explores the role of nature in oil palm plantations. Specifically, to analyze the landscape characteristics of the Macondo plantation for two purposes: a) ecologically, the landscape composition and configuration of the plantation enhance landscape connectivity and pest control service, 2) socially, owing to the landscape characteristics, plantation workers perceive social landscape values, well-being and better working conditions in the plantation. Chapter 1 is the general introduction describing the oil palm plantations worldwide. Chapter 1 summarizes the ecological and social effects of rapid oil palm expansion in tropical regions. Chapter 2 is a description of the study area. The chapter begins with a description of the Meta department and the municipality of Mapiripán to understand the general context of the eastern region. Following is a description of the company Poligrow Colombia SAS and the Macondo plantation where the case study was performed. Chapter 3 is the theoretical framework of the project. Chapter 4 is the research design and research questions. In Chapter 5, the landscape analysis of the Macondo plantation is related to pest occurrence. To show relationships among the landscape structural types, land cover, and pest occurrence, a landscape analysis by multivariate cluster analysis and an NMDS ordination were performed. The results show that a heterogeneous plantation improves landscape connectivity and control pest populations. In Chapter 6, the specific nature-enhanced plantation design can provide social landscape values, SLV, to workers is examined. The results on the structural landscape analysis of the plantation, in Chapter 5, were analyzed jointly with the results from the participatory mapping with plantation workers. The correspondence between landscape analysis and the location of the perceived values is analyzed, revealing socio-ecological hotspots (e.g., epiphytarium). It highlights the relationship between the landscape characteristics of the plantation and the social landscape values perceived by workers. Workers perceive most social landscape values in the prevalence of landscape connectivity and heterogeneity. Chapter 7 addresses whether plantation workers relate to and perceive nature (e.g., gallery and riparian forests) and non-natural areas (e.g., crops such as oil palm) in the plantation. Using qualitative content analysis from focus group discussion and in-depth interviews with workers, I infer they derive a great variety of values and also experience ambivalent relationships towards nature in the plantation. Through the perceived benefits to humans and other species, a possible naturalization process might happen on such a nature-enhanced plantation. Finally, Chapter 8 is the general discussion and conclusions.Item Anthropogenic pressure in a marine world: Distribution, movement, diet and parasite infestation of red-throated divers Gavia stellata in the context of habitat change(2022) Kleinschmidt, Birgit; Quillfeldt, Petra; Wolters, VolkmarInformation on the behaviour and ecology of seabirds provides an important basis for better understanding the effects of changes in their habitats and developing conservation strategies accordingly. The red-throated diver Gavia stellata breeds in Arctic regions and is found in coastal marine offshore areas outside the breeding season. German waters contain some important non-breeding areas for this species, with internationally relevant populations such as in the German Bight. Nevertheless, these areas are also characterized by high anthropogenic use, leading to strong responses in this species with avoidance distances of over 10 km and significant changes in distribution patterns. If these responses have long-term effects at the population level is still unclear due to the lack of basic studies on behavioural-ecological aspects. Therefore, this dissertation, aimed at filling the knowledge gapes related to dietary, migratory, and disease ecology. The cumulative dissertation presented here is structured into three chapters, each of which addresses a behavioural-ecological topic presented in chapters 1, 2, and 3, respectively. Specifically, the diet of red-throated divers in the German Bight was analysed using DNA-metabarcoding on sample sets from two consecutive years (Chapter 1). The results showed an opportunistic piscivorous prey spectrum which, however, included a high proportion of energetic rich species in both years, with clupeids as the most frequented prey items. These findings confirm other studies from e.g. the Baltic Sea. The continuous presence of high-energy prey fish in the diet helps to explain the importance of the German Bight due to the high availability of those fish species. Migratory behaviour and site use throughout the year, was studied using satellite telemetry and analysis of isotopic values from feather samples (Chapter 2). Breeding, moulting, and wintering sites were successfully determined of individuals inhabiting the German Bight. Migratory behaviour was characterized by regular staging stops, probably to refuel energy reserves. Individuals breeding in northern Russia showed low migratory connectivity, indicated by variable site use among individuals. However, between two consecutive years, individual movement patterns showed high repeatability. Furthermore, a correlation between migratory phenology and the location of the breeding area was revealed. A potential stressor, which has not yet been investigated in red-throated divers, could be the infestation of blood parasites or haemosporidia (Plasmodium, Haemoproteus, Leucocytozoon), which can have a negative impact on health (chapter 3). Haemosporidia were detected in red-throated divers using molecular tools, with low prevalence and identification of one new lineage each of Leucocytozoon and Plasmodium. The low prevalence indicates a rather insignificant impairment. In summary, the results of the behavioural ecological aspects reported in this dissertation fill previously existing knowledge gaps about a seabird species sensitive to disturbance. The integrative approach of dietary, migratory and disease ecology illustrates that for migratory species, impairments that occur during the annual cycle should be considered cumulatively rather than in isolation. Along their migration route red-throated divers, as well as other migratory species use various staging and stop-over sites and thus are vulnerable to experience a number of impacts, such as gill net fisheries, pollution or ship traffic, that individually, may still be compensable, but collectively might lead to population-level impacts.Item Application of machine learning for the prediction of stable isotopes of water concentrations in streams and groundwater(2021-09-03) Sahraei, Amirhossein; Breuer, Lutz; Siemens, JanThis dissertation introduces the application of machine learning to isotope hydrology. The recent development of laser spectroscopy has made it feasible to measure stable isotopes of water in high temporal resolutions up to sub-hourly scales. High-resolution data provides the opportunity to identify the fine-scale, short-term transport and mixing processes that are not detectable at coarser resolutions. Despite such advantages, routine and long-term sampling of streams and groundwater sources at high temporal resolution is still far from being widespread. Novel approaches that are able to predict and interpolate infrequently measured data at multiple sources would be a major breakthrough. This dissertation focuses on the application of machine learning and hyperparameter optimization to efficiently predict high-resolution isotope concentrations of multiple stream and groundwater sources in the Schwingbach Environmental Observatory (SEO), Germany. In a first step, an automated mobile laboratory was utilized to automatically sample and analyse stable isotopes and water quality for multiple water sources at 20 min intervals in situ. Prompt responses of isotope concentrations to precipitation revealed that shallow subsurface flow pathways rapidly delivered water to the stream. A Spearman rank analysis indicated that precipitation is a main driver of event and pre-event water contribution. In a second step, Artificial Neural Network (ANN) and Support Vector Machine (SVM) were optimized to predict maximum event water fractions in streamflow on independent precipitation events using only precipitation, soil moisture and air temperature as input features. The optimized SVM outperformed that of ANN with an RMSE of 9.43%, MAE of 7.89%, R2 of 0.83, and NSE of 0.78. A systematic hyperparameter optimization approach showed that an adequate number of hidden nodes and a suitable activation function enhanced the ANN performance, whereas the performance of SVM was directly related to the selection of the kernel function. Finally, a Long Short-Term Memory (LSTM) deep learning model was optimized using a Bayesian optimization algorithm to predict high-resolution time series of isotope concentrations in multiple stream and groundwater sources using a set of explanatory data that are more straightforward and less expensive to measure compared to the stable isotopes. The LSTM could successfully predict isotope concentrations of stream and groundwater sources using only short-term sequence (6 h) of measured water temperature, pH and electrical conductivity with an RMSE of 0.7‰, MAE of 0.4‰, R2 of 0.90, and NSE of 0.70. In conclusion, machine learning methods are promising tools for the prediction of variables that are difficult, expensive or cumbersome to measure.Item Biodiversity and ecosystem services in cultural landscapes of Germany and Japan(2023-01) Sasaki, Keiko; Wolters, Volkmar; Hotes, StefanThis cumulative dissertation takes a comparative approach to studying the spatial patterns of biodiversity and ecosystem services in agricultural landscapes of Germany and Japan. In both countries, biodiversity and ecosystem services maintained by the respective traditional farming systems are declining due to agricultural intensification and land abandonment. Landscape associations of bird species that are typical in agricultural landscapes of Germany and Japan were analyzed jointly, while spatial associations of ecosystem services were investigated using data from Japan only owing to the different frameworks used by public institutions for gathering data. Findings from the latter study were compared to published results from the literature in Europe. Both studies were carried out at the national level. Distribution data on bird species were obtained from nationwide monitoring programs, and metrics of landscape structure and ecosystem services linked to agroecosystems were calculated based on spatial datasets and public statistics using a geographical information system. The first chapter demonstrates that farmland bird diversity responds to the proportions of farmland cover and semi-natural habitat cover in a similar way between Germany and Japan. The results also suggest that landscape associations can vary according to the countries. Woodland edge density had a pronounced effect on species numbers in Germany where farmland dominates. In contrast, farmland cover was more relevant in Japan than in Germany; in Japan, where forests dominate, the effect of woodland edge density was only marginal. The importance of open habitats and landscape heterogeneity for maintaining farmland bird diversity was supported by these findings. In the second chapter, landscapes in Japan specializing either in commodity production or in cultural services and habitat features were identified based on indicators for agricultural ecosystem services and farmland biodiversity. The latter landscapes coincided with areas at risk of land abandonment. The spatial aggregation of biodiversity and culturally valuable resources on marginal land, where traditional farming systems are likely to persist, underlies the importance of conserving the structural features of traditional farming systems. To conclude, this dissertation supports the notion that landscape structure, biodiversity, and ecosystem services are linked significantly, and that such links apply generally in Germany and Japan.Item Failing synergies among public programs: the economy-wide effects of one rural credit and two social protection programs simultaneously implemented in Southern Brazil(2021) Specht, Gabriel; Nuppenau, Ernst-August; Petrick, MartinWhile innumerous public programs are implemented side by side in rural areas, the effects produced by simultaneous implementation of different programs on rural households and rural economies remain understudied. Even though several studies mention the potential synergies emerging from the combination of agricultural development programs, aimed at farming households, improving agricultural production and productivity, such as staples, and of social protection programs, aimed mostly at poor households, lifting liquidity constraints and increasing demand for goods, the evidences are rare. Several studies assessing these programs individually attest that they affect local commodity and factor markets, consequently affecting other (non-)participating households, and therefore, the local economy. However, it remains unclear what effects are produced by the simultaneous implementation of agricultural development and social protection programs in rural areas and whether they produce synergetic outcomes in rural economies, especially in the commodity and factor markets, and how they affect the welfare of rural households. Therefore, our objective is to assess the economy-wide effects produced by the simultaneous implementation of public programs in a rural village in Southern Brazil. For that scope, we assess the effects of one agricultural development program, namely PRONAF, a subsidized rural credit program targeted towards smallholder farmers, and two social protection programs, namely Bolsa Família, a conditional cash transfer program aimed at poor households, and of the rural pension program, a pension program targeting senior rural household members. We adapted the STAGE CGE model to assess the impacts produced on the economy of the Rincão dos Maia village, a rural community in Southern Brazil strongly characterized by smallholder farming. To assess the synergies in the implementation of programs, we created 7 different scenarios simulating an increase in the public budget of 10 thousand BRL for all programs alone and all their combinations. As a subsidized rural credit program, the scenarios simulating an increase in PRONAF budget were implemented by increasing the indirect taxes on agricultural activities, while the change in the budget of social protection programs was simulated by increasing the household-specific transfers received from the government. Our results reveal that there are no synergetic outcomes in the simultaneous implementation of agricultural development and social protection programs in Brazil. In our simulations, no combination of program budget increase produced outcomes greater than the increase in the budget of the programs alone. While an increase in the PRONAF budget increases cash crop production, it pressures down agricultural production for the local market and household consumption, driving up prices of locally produced and consumed commodities. An increase in the budget of the social protection programs produces the opposite effect, promoting local production of goods consumed by the households while reducing the production of cash crops. These results highlight the mismatch in the demand and supply of local commodities: while PRONAF increases cash crop, exported to the rest of Brazil, it does not match the increase in the local demand for staples, but rather suppresses it, putting additional pressure on local staple prices, and consequently reducing household welfare. Even though the sensitivity analysis shows that the results vary considerably by changing model closures, especially in terms of factor mobility, the perspective of producing synergies is very limited, as the change in commodity supply produced by PRONAF is not matched with the increase in commodity demand produced by the social protection programs. Furthermore, the engagement of local households in subsistence activities reduces the scope of transmission of effects produced by policy changes.Item Germination, Establishment and Distribution of Hardwood Floodplain Forest Species(2021-05) Schindler, Melanie; Otte, Annette; Müller, ChristophHardwood floodplain forests are among the most structure- and species-rich ecosystems in Central Europe. Due to anthropogenic changes, they have been drastically reduced and belong nowadays to the most endangered ecosystems. Therefore, the restoration of floodplain forests is a central goal of alluvial restoration projects, but at the same time a difficult task due to the complex environmental conditions. Since flooding tolerance can be regarded as key factor for successful establishment of plant species in floodplains, this thesis deals with flooding tolerance of different hardwood floodplain forest species. Further, this thesis combines experimental studies under controlled hydrological conditions with field experiments. The latter where conducted in one of the largest alluvial restoration areas in Germany – the dike relocation area “Lenzen-Wustrow”. In general, the results of my thesis showed that an increasing flooding duration negatively affects plant performance. Further, after second flooding in the following year, similar flooding tolerance patterns were observed. However, most species were able to recover better after the second flooding compared to the first one, probably also because the individuals were one year older at this point. Nevertheless, a previous flooding experience, regardless of its duration, showed no changes in the flooding tolerance of the saplings, indicating that there is no flooding stress memory in the investigated species. Furthermore, I revealed that for the classification of flooding tolerance, it is highly important to include a recovery period. By this, misjudgments of flooding tolerance patterns of species can be avoided, as plants can either recover after flooding or suffer even more. In general, the species-specific differences in flooding tolerance could be explained by their ability to react to the resulting flooding stress by using morphological, physiological and metabolic adaptations. Species that are able to quickly generate different structures in a large number will cope better even with long periods of flooding. Although the assessment of the flooding tolerance of different species depending on flooding duration is useful in the context of restoration planning processes, it must be considered with caution as the incorporate variations in site conditions, hydrological parameters and ecological requirements are not included. The field study showed that processes in floodplains are highly dynamic and that long flooding as well as long drought periods must be considered as separate extreme events. Both are unfavorable during early establishment, even though, the mean annual number of flooding days was within the typical growth range of the hardwood floodplain forest zone. Further, under field conditions, additionally to the hydrological regime, many other factors can influence the establishment of trees, such as herbivory, which caused a high mortality in the study area. As comparable studies in restored floodplains do not exist until now and I could demonstrate how necessary long-term study periods are, it is important that more studies and assessments of establishment success are carried out in the field, covering longer study periods and also take into account the interaction of the various influencing factors more precisely. Only then, it will be possible to provide better predictions and possible solutions for future restoration measures.Item Inferring hydrological process understanding using models and large-sample data sets(2021-02-10) Jehn, Florian Ulrich; Breuer, Lutz; Siemens, Jan; Schneider, LeaCatchments are complex systems, which have evolved under the influence of environmental processes over long periods of time. Due to this inherent complexity, it is often difficult to understand what forces the hydrological behavior of a given catchment. The two most common approaches to better understand catchments are creating hydrological models to test which hypothesis of catchment functioning works best or to look at the catchment characteristics and try to infer the most important forcing directly from this. This dissertation uses both approaches to reach a more holistic understanding of catchment functioning. The starting point of this dissertation was an earlier publication of mine, which used an innovative way for model development, the so called “incremental model breakdown”. This new approach starts with a complex model, incrementally deactivates processes and checks which process deactivation causes the model to fail. All processes that lead to a failure when deactivated show that they are important for the model. This enables a more thorough exploration of the space of possible model structures than traditional approaches, which start from predefined structures. However, during the development of this approach it became apparent that model parameters are able to compensate extensively for the omission of processes. Therefore, larger and well-understood data sets are needed to form hypotheses of catchment functioning that could be tested by incremental model breakdown. Based on this prior knowledge and to lay the foundation for future research, this dissertation builds on the incremental model breakdown approach and examines two large sample data sets with different methods. As the main problem of the new model building approach was the way it handles the model parameters, the first part of this dissertation focusses on the intricate interaction between model complexity and parameter uncertainty. This is done by exploring the trade-offs between tightly constrained parameters and the ability of the hydrological models to predict hydrological signatures that capture the behavior of a river. The results show that there is a clear trade-off along the axis of complexity for those models. The simpler a model is, the better its ability to constrain parameters, but the worse are the results of an independent validation of its realism using hydrological signatures. Those results highlighted again that hydrological models can only be as good as the hypothesis forming their basis and those hypotheses can only be found and improved by looking at real catchments’ data. These datasets need to contain the hydrological behavior and characteristics of catchments to facilitate deriving hydrological process understanding – and develop appropriate models that reflect this catchment’s understanding. Therefore, in the second part of my thesis, is about the exploration of two large hydrological datasets. The first step was an analysis of the CAMELS dataset, a large-scale open access dataset that contains catchments from all over the continental United States. This allows to determine the most important factor for the overall hydrological behavior, namely the climate, and more specifically, the aridity and the frequency of large precipitation events. However, the results also show that this climatic forcing can be found more directly in some catchments than in others. This was likely a problem of scale, given the continental domain of this study. To better understand why this is the case, we established a second dataset which only contained catchments from Hesse, Germany, for the third part of my work. This allowed looking at how catchments with different characteristics behave under the same climatic forcing. The focus here was the complexity of the storage-discharge relationship. The results showed that the hydrological signal of the climatic forcing is mainly influenced by the catchment’s permeability, conductivity, geology, soil and, to a lesser extent, its topography. It also showed that the complexity of the hydrological response differs strongly between catchments. While some catchments show a storage-discharge relationship that is almost exactly an exponential function, others show a more erratic behavior. The properties of the simple catchments all facilitate a higher interconnectedness of the storage system of the catchment; this indicates that the complexity of a catchment’s behavior is strongly linked to its overall connectivity of water pathways. To finally use this improved hydrological understanding and connect it to model structures, preliminary tests link the catchment complexity with modelling ease. For this, I used the simple HYMOD model and evaluated its performance for catchments of differing complexity. Those results showed that the simplicity in behavior is connected to the model performance. The simpler the storage-discharge relationship, the simpler the model for the catchment can be. The findings of this dissertation highlight that even though it is possible to change model structures and calibrate parameters to get results with high values for the objective function, those models can still have difficulties in independent verification. This indicates that the models are often “right for the wrong reasons”. Only if we thoroughly understand datasets that capture a wide variety of hydrological behavior and catchments characteristics will we be able to construct more realistic hydrological models that are “right for the right reasons”.Item Institutional innovation in groundwater governance in Odisha (India): A numerical simulation in water user association (WUA)(2023) Haldar, Surajit; Nuppenau, Ernst-AugustIn this study, I enquired the scope of cooperation in water resource governance that has potential to enhance net farm income by reducing the cost of water. Water user association (WUA) on groundwater is a government-subsidised cooperative model where farmers make collective decisions regarding water distribution. Many times, due to improper management of the groundwater resource system and its physical structure, cooperation collapsed. Moreover, subsidized irrigation water exaggerated water extraction, and as a result, the water table declined beyond the bottom of the well, threatening the sustainability of the WUA. In this study, I described diversity of agricultural production systems (APS) under similar community irrigation distribution systems. From diverse APS, I developed distinct farm types and substantiated them with theoretical viewpoints and empirical data. I further maximized net return of a farm by adopting cost effective cropping pat-terns. To maximize water conservation in a community irrigation distribution system, an incentive scheme in a principal-agent ( P-A) mode is devised that features a cooperative model. The P-A model results indicated that economic incentives offered for water saving from the WUA motivated farmers to adopt water saving activities at the farm level. In addition, WUA achieved maximum total water savings by reducing pumping operation. However, the impact of economic incentives for water saving differs by farm type. Therefore, the study recommends that a WUA should amend its water distribution institutions to encourage adoption of water-saving cropping pat-terns by member farmers by advancing multiple fixed and variable incentives.Item Landscape structure and land use in the Greater and Lesser Caucasus of Georgia: Impacts of societal change and potentials for sustainable development(2022) Theißen, Tim; Waldhardt, Rainer; Aurbacher, JoachimIn two Georgian high-mountain landscapes, Kazbegi in the Greater and Bakuriani in the Lesser Caucasus, the land use and the structural diversity of the cultural landscape have been investigated in three studies. Along steep altitudinal gradients a variety of mountain biotopes and habitats of open lands and forests are located in these landscapes. Land use and landscape structure is substantially influenced by local small-scaled subsistence farming with low number of cattle and small parcels of cultivated land for vegetable cultivation and haymaking. In both regions, agriculture is practiced on low-yielding marginal locations due to climate conditions in the high mountains. The large number of heated glasshouses for vegetable cultivation in the Kazbgei region is an example to tackle the difficult high-mountain farming conditions in an energy-intensive way. Both study regions are also subject to consequences of the countrywide political and economic restructuring since Georgian independence in 1991. On the one hand, urban regions are suffering by outmigration of the population, especially by the youth, with adverse consequences for the agriculturally used land and therefore for the landscape structure and biodiversity. On the other hand, since the 2010ies the tourism begins to flourish in both regions, with increasing employment possibilities for the population in the tourism sector. In the field of tension between the two opposing developments, the synthesis´ investigations focus on three different focal points. However, the land-use pattern and the structural diversity of high mountain cultural landscapes are always the heart and the linkage of research and evaluation. First, for the Bakuriani region in the Lesser Caucasus the land-use pattern and forest structure have been investigated. In this Lesser Caucasus study area forest is the dominating land cover. Considering this, the naturalness of the diverse mountain forest types were analyzed along altitudinal belts. These forests were characterized by a high degree of naturalness and a traditional silvo-cultural land-use system of forest pastures and forest meadows. Second, for the Kazbegi region in the Greater Caucasus the land-use change from 1987 to 2015 have been analyzed and quantified in consideration of societal and structural development. In this study, changes in land use and land cover have been quantified spatially explicit in relation to the distinctive high mountain topography at settlement level. Third, interdisciplinary and sustainable land-use concepts have been developed for the Kazbegi region to promote the profitability of agricultural production while respecting the ecology of the mountain landscape. With ecological and socio-economic parameters and indicators three normative land-use scenarios have been developed to meet sustainable development goals of the UN. These scenarios can help optimizing farm management and the use of inputs in the local agriculture. According to the described studies and in comparison to various scientific concepts like the multifunctionality of landscapes, ecosystem services, the concept of hemeroby, and ‘One Health’, the landscape structure and the pattern of land use in both regions were studied and evaluated. Landscape structure today is still characterized by traditional agricultural land use adapted to high mountain conditions. However, in both study regions the retreat of agriculture is evident, indicated by increasing shrubification and reforestation. Non-intensive high-mountain farming that is adapted to the diverse topography with a small-scaled pattern of various climatic conditions shall be decisive, i.e. beneficial and preserving, for an exceptional high mountain biodiversity. The agricultural cultivation of the mountain landscape is a formative factor for biodiversity and species protection in both regions. Additionally, it also shapes the landscape in the sense that it is currently gaining in national and international tourist appeal. The importance of the two core issues mentioned above, high mountain biodiversity and tourism, has been recognised by politicians in the recent past and various protection measures and support actions have been formulated and established.Item Optimum use of irrigation water: Bioeconomic household modeling of small-scale irrigation scheme in South Central Ethiopia(2023) Adela, Fitsum Assefa; Aurbacher, JoachimThe Ethiopian economy is agrarian, by and large. This is evidenced by the fact that the agricultural sector contributes nearly 36 percent of the GDP and employs 80 percent of the population. However, the sector’s growth has been impended by institutional, environmental and other factors. The sector is dominated by smallholders who are vulnerable to external shocks and have limited capacity to invest on their land. This causes low productivity to prevail in the sector, which further exacerbates the prevalence of rural poverty. In recent times, the government of Ethiopia promotes the expansion of small- scale irrigation by optimally using the bounty of water resources in a bid to reducing poverty and food insecurity. But, many of the surface water are dominated by rivers (both small and big) which flow cross different localities. The rivalry in using the water across the course of the river causes continual conflict among communities living on different courses of the river. In the study area, there is a small river that passes through upstream, middle stream and lower stream localities; and there is conflict among users along the way. Despite the prevalence of such burning issues, studies on the optimal allocation of water and on the impact of irrigation on poverty using rigorous economic models are scanty except some that have rather focused on identifying factors urging households to use irrigation. This justifies the need for examining the extent to which the flowing water is optimally shared among users across the course of the river in a way that brings maximum benefits. Against the backdrop of the aforementioned gaps, this study is, therefore, an attempt to bridge the observed gaps by using both bioeconomic and econometrics approaches. Data have been collected from 240 households, which live in upper, middle and lower parts of the stream. The descriptive results have shown that there is significant difference in the socio-economic characteristics between farmers who have access to irrigation and those who do not. Poverty analysis was conducted using the Foster–Greer–Thorbecke (FGT) indices based on own constructed consumption poverty line. The incidence, depth, and severity of poverty were found to be higher among farmers who do not have access to irrigation. Assessment of the physical irrigation infrastructure indicated performance problems of the canals and a significant amount of water loss during transportation. Irrigation is undertaken in turns based on a schedule set by Water Users Association committee. There is also a clear difference in production patterns between households living in upstream, middle stream and lower stream parts of the river. Those households which live in the upper stream produce more Khat than households living either in the middle or lower stream. In fact, in relative terms, those households which live in the middle parts of the river produce more Khat than households living in the lower stream. In the same pattern, the amount of water used per ha by households in the upper stream is by far greater than the amount of water used per ha by households in the lower parts of the river both for Khat and sugar cane production. This could be associated to the location advantage upper stream households have to access more water. The results of the logistic regression showed that institutional set ups and governance of the irrigation scheme, access to information and social network, and water scarcity level have significant impacts on farmers’ decisions to irrigate. Among the factors, the pesticide amount used, and landholding size have a positive and significant impact on the farm income of the respondent households. Plot size and distance to nearest market, on the other hand, have a negative and significant impact on farm income of households. Regarding per adult equivalent food consumption, households’ farm income, non-farm income, and household asset have positive and significant impacts. Household size and dependency ratio, on the other hand, have a negative impact. Further analyses were carried out using bioeconomic modeling in order to identify alternative policies that ensure optimal water allocation along the stream. There are two cash crops (sugarcane and Khat) that are produced in the study area. Khat consumes more water than sugarcane and has undesired socio economic impacts. This situation requires interventions to be designed to reduce the production of Khat such that the water could be optimally allocated across the course of the river. Towards this end, three scenarios were considered for simulations namely improving the efficiency of water use and taxing Khat production, water tax and allocating more land to Sugarcane were considered. Improving efficiency of sugarcane production and taxing Khat improves the production of sugarcane. Water pricing promotes the production of khat, while land allocation promotes the production of sugarcane. Based on the aforementioned analysis, the study pinpointed the fact that both institutional and social factors should be given prime attention to ensure fair distribution of water across the course of the river and to instigate farmers to use irrigation. Besides, enhancing the productivity of sugarcane through improved technology should be the main concern of stakeholders. In this regard, a system that tends to enhance the productivity of sugarcane should be in place such that the community would allocate more land to sugarcane which eventually ensures sustainable water use across the course of the river ultimately benefiting users.Item Oxide Coatings on Nickel-Rich Layered Cathode Active Materials for Thiophosphate-Based Solid-State Batteries(2023) Kitsche, David; Janek, Jürgen; Lepple, MarenLithium-ion batteries (LIBs) lay the foundation of today’s portable electronics, which have profoundly changed modern society, providing mobile communication and many other functionalities. However, recently they have drawn even more attention, especially as energy storage devices for electric vehicles (EVs) which are expected to replace vehicles powered by an internal combustion engine in the long run. This has strongly driven the development of LIBs, which are approaching physical limits regarding their energy density. Solid-state batteries (SSBs) are regarded as a promising next-generation battery technology. They are hoped to enable higher energy densities by making use of a Li metal anode. Not containing a flammable liquid, they could also eventually turn out to be safer than LIBs. Among the classes of solid electrolytes (SEs) that could replace their liquid counterpart in conventional LIB cells, thiophosphates stand out due to their high ionic conductivities and favorable processability. The main drawback of thiophosphates is their low thermodynamic stability, leading to a number of incompatibility issues at both anode and cathode. On the cathode side of SSBs, severe thiophosphate oxidation has to be prevented by using protective layers, especially on the cathode active material (CAM). Many such CAM coatings have been proposed in the past and were shown to have functionalities beyond preventing SE oxidation. Moreover, different methods have been used to deposit these layers on CAMs, each with different capabilities regarding the achievable coating thickness and morphology. The aim of this doctoral project was to prepare, characterize, optimize and test protective CAM coatings on LiNi0.85Co0.10Mn0.05O2, a Ni-rich NCM-type CAM, for use in thiophosphate-based SSB cells. The work resulted in publications on three different metal oxide coatings. Two of them are based on the use of atomic layer deposition (ALD), a method that previously had rarely been employed for this application. Nanometer-thin, conformal and adjustable layers of the binary oxides HfO2 and ZrO2 could be obtained. The coatings are nanocrystalline and beneficial for the cycling performance of the NCM CAM, especially when a post-heat treatment at moderate temperatures is performed. A systematic characterization of the ZrO2@NCM after heat treatment at temperatures ranging between 300 and 700 °C revealed a multifaceted evolution of the (sub)surface layer. This includes changes in crystallinity and a reaction between substrate and coating. The two studies showed that ALD is a viable tool to prepare high-quality model-type coatings that are well-suited for systematic investigations into the property-performance relationships and thereby advance the understanding of the working principles of CAM coatings. Apart from that, a facile wet chemical method was used to deposit a composite oxide coating consisting of Li3NbO4 nanoparticles and Li2CO3. This protective layer enabled excellent cycling performance regarding reversible specific capacity and rate capability (212 and 150 mAh/gCAM at 0.2 and 2.0 mA/gCAM, respectively) as well as stability (more than 80% capacity retention after 200 cycles). In doing so, the coating compared favorably to common lithium niobate coatings, thus showing that there is still room for improvements when it comes to wet chemical coating methods and CAM coatings in general.Item Spatial analysis of Sibbinda rural settlement development and deforestation in Zambezi region, Namibia(2022) Tubulingane, Sabeho Booysen; Dittmann, Andreas; Mwewa, LameckSpatio-temporal analyses using GIS and remote sensing techniques are tools used to model rural settlement development as a catalyst of deforestation. Spatial analyses were performed using IDRISI 17.0 software. A supervised classification-maximum likelihood algorithm was applied to detect land cover/land use changes observed in the study area. Study land cover was classified into four major land use classes, vegetation, land cleared for settlement purposes, dwelling units/buildings and bare land. Linear and multiple regression were applied to predict and quantify the contribution of roads, building construction and land clearing to deforestation. Past, present and future land use and land cover changes due to Sibbinda rural settlement development favour deforestation. In a rural settlement setup with no major road network development; deforestation is positively associated with road networks for a limited time period, and thereafter as deforestation moves towards saturation stage, it becomes negatively associated with road networks. Vegetated areas that are easily accessible to humans are more likely to be initially deforested. At the early stage of deforestation, the distance of an area from a road network is the most important factor of deforestation in that specific area. As deforestation increases in the area the distance from buildings becomes the most significant factor of deforestation. Deforestation hotspots at Sibbinda are expected in the northwest direction, in areas far from roads, yet more densely vegetated. Reforestation is very low at the Sibbinda settlement, as it is mainly a result of natural processes. To minimise the extent of deforestation, future settlement development projects need to correspond to the aims of SDG11, so that forests are effectively preserved. There is a need to draw future settlement land-use plans depicting the future growths of the settlement and forestry conservancy areas (mainly in the northwest of Sibbinda).Item The Roles of Chemical Energy Carriers in Future Renewable Energy Systems(2023) Hampp, Johannes; Düren, Michael; Winker, PeterWith climate change mitigation as one of the key goals of the energy transition, the use of fossil fuels and their connected greenhouse gas emissions has to decline sharply in the future. Renewable generation technologies alone however will be insufficient to fill the gap left by fossil fuels. Other than fossil fuels, renewable energy sources are constrained by their weather dependency and land requirements, making complementing storage and firming technologies necessary to ensure a reliable energy supply. To be successful, the energy transition has to address these key challenges of renewables, regional availability and weather dependency. Chemical energy carriers are a puzzle piece to the energy transition, expected to address these two challenges. They can be synthetically produced from renewable energy and sustainably sourced feedstocks. With properties similar to currently used chemical energy carriers of fossil origin, they offer attractive characteristics for use in energy storage, transport and as industry feedstock. However, because of their distinct chemical and physical properties, they are expected to be suited differently well to fulfil the various roles in future energy systems. In this thesis, the potential of candidate chemical energy carriers to fulfil the various roles are investigated. Using bottom-up energy system modelling, their performance and suitability for energy and feedstock imports, long-distance electricity transport as alternatives to demand-side flexibility, and long-term strategic energy storage are evaluated based on techno-economic criteria. The findings are complemented by the introduction of a software package for modelling input data on renewables for energy system models and the foundations for a global energy system model of high temporal and spatial resolution. With its results, this thesis lays the basis for future, more comprehensive analyses of the global roles of chemical energy carriers and their interactions with regional energy systems.