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Institut
- Fakultät Nachhaltigkeit (18) (entfernen)
European species-rich grasslands are threatened both by land use intensification as well as land abandonment. The studies shown in this thesis tested the possible use of ecological knowledge to ensure hay productivity whilst maintaining diversity of grasslands, with a view to informing ecological restoration. The overall approach was to understand interactions between plants, to study diversity effects on productivity, and mainly investigate how plant functional groups that arrive first in the system can create priority effects that influence community productivity both above- and belowground. A grassland field experiment was established and monitored for four years, in order to verify the effects of manipulating the order of arrival of different plant functional groups, as well as the sown diversity level on productivity and methane yield. The overall findings were: a) sowing legumes first created priority effects aboveground (higher biomass) and belowground (lower root length), plants invested less in roots and more in shoots, b) priority effects were more consistent below than aboveground, c) sown diversity did not affect aboveground biomass, d) the order of arrival treatments indirectly affected methane yield by affecting the relative dominance of plant functional groups. Since the researchers lack information on how legumes and non-legumes interact spatially belowground, (particularly related to root foraging) a controlled experiment was performed, using two grass species and one legume. The identity and location of the neighbours played a role in interactions, and the order plants arrived modulated it. When the focal species (grass) was growing with a legume it generally equated to the same outcome as not having a neighbour. Roots from the focal species grew more toward the legume than the grass neighbour, indicating a spatial component of facilitation. Since these studies involved root measurements, a method study was also conducted to verify how comparable and accurate are root length estimates obtained from different techniques. Results showed that the use of different methods can lead to different results, the studied methods did not have the same accuracy, and the automated methods can underestimate the root length. Overall, the results allow to conclude that different groups of plants arriving before others affected above and belowground biomass, roots may be key drivers during the creation of these priority effects, and interaction outcomes between plants depended on neighbour identity and location, modulated by the order they arrive in. The results suggest that priority effects can be used by sowing different species or plant functional groups at different time to steer a community to a desired trajectory depending on the restoration goal. However, there is a need to test contingency, potential, and long term impacts of such possible tools for restoration.
This thesis aims at contributing to the better understanding of the roles of international and domestic institutional and governance patterns for corporate sustainability practices. By combining governance and new institutionalism approaches it bridges the gap between the close look at specific corporate sustainability (CS) policies and the broader view on institutional frameworks. The qualitative comparative approach aims to provide deeper insights on the implementation of different governance schemes by transnational corporations ((TNC). Finally, the conclusions might allow for the development of a) recommendations for the balancing of TNCs' CS management between global and domestic requirements, and b) policy recommendations in the field of CS governance. The overarching research question is as follows: What role do national governance patterns play in comparison to global governance practices in shaping the corporate sustainability (CS) management of transnational corporations (TNCs)? In order to further operationalize this research objective, it is structured into three subquestions: (1) What are relevant institutional factors and global governance patterns for corporate sustainability/ Corporate Social Responsibility (CSR)? (2) What are relevant institutional factors and national governance patterns for corporate sustainability/CSR in Germany, the US, and India? (3) How do these national and global governance patterns influence TNCs' CS management? The first two questions aim at tracing the institutional framework and governance patterns at both national and international levels by identifying norms, stakeholder expectations, prevalent modes of governance and actors involved in governance processes. On this basis, the third question targets TNCs' reaction to internationally varying governance patterns. Here, it is of main interest how relevant governance instruments are perceived by business actors and to which extent their sustainability management at the companies' headquarters and subsidiaries reflect global and national institutional and governance patterns. In order to answer these questions, literature research and a structured qualitative analysis have been conducted. The concepts of CS and CSR build the basis to analyze how TNCs and their subsidiaries manage their social and ecological corporate responsibilities. Against this conceptual background, the research question is approached empirically by the means of an international comparison. Three institutionally highly diverse countries were chosen: Germany, India and the US. India, an emerging market economy, was included to increase the diversity of the sample and to close the research gap indicated above. In order to identify the differences in governance for CS in these three countries, document analyses and 42 guideline-based interviews with experts from governments, NGOs, trade unions and trade associations were carried out. At the same time, global governance instruments for corporate sustainability – which are already relatively well researched - were identified by analyzing the relevant secondary literature. In a second step, in order to explore how TNCs strategically deal with the multitude of different governance approaches at their headquarters and subsidiaries, three case studies of Germany-headquartered transnational corporations in the chemical and engineering industries (Siemens, BASF and Bayer) have been conducted.
Wood-pastures have been present in Europe for thousands of years. This form of grazed landscape, combining herbaceous vegetation with trees and shrubs, has often co-evolved with its human users into complex social-ecological systems (SES). Wood-pastures are associated with high cultural and biodiversity values and are an example of the sustainable use of resources. However, due to their often relatively labour-intensive management and low productivity, large areas of wood-pastures have been lost over the last century. The loss of these areas means not only the loss of biodiversity on both local and landscape scales, but also the loss of traditional farming and cultural heritage in some regions. Across the European Union, wood-pastures are facing different problems and are embedded in different social systems and ecological environments. Yet they are all affected by global change and common European policies. To understand the challenges for wood-pastures in a changing world, a holistic approach combining different disciplines is needed. This dissertation therefore is analyzing wood-pastures across Europe as a Social-ecological System, combining ecology and social science with the aim to identify the barriers and drivers for wood-pastures persistence into the future.
Smartphones make intensive use of precious metals and so called conflict minerals in order to reach their high performance in a compact size. In recent times, sustainability challenges related to production, use and disposal of smartphones are increasingly a topic of public debate. Thus, established industry actors and newly emerging firms are driven to engage in more sustainable practices, such as sustainable sourcing of materials, maintenance services or take-back schemes for discarded mobile phones. Many of these latter efforts can be related to the concept of a circular economy (CE). This thesis explores how CE-related value creation architectures (VCAs) in the smartphone industry contribute to slowing and closing resource loops in a CE. In order to analyze these new industry arrangements, transaction cost theory (TCT) is used as a guiding theory for a make-or-buy analysis. Combining TCT with the concept of a CE is a novel research approach that enables the empirical analysis of relationships between focal actors (e.g. manufacturers) and newly emerging loop operators (e.g. recycling firms) in the smartphone industry. Case studies of such VCAs are conducted with case companies drawn from the Innovation Network on Sustainable Smartphones (INaS) at Leuphana Universtity of Lüneburg and analyzed regarding their involved actors, partnerships, circular activities, motivation and perceived barriers. Evidence from the conducted case studies suggests that asset specificity for circular practices increases for higher order CE-loops such as maintenance or reuse, therefore long-term partnerships between focal actors and loop operators or vertical integration of CE practices are beneficial strategies to reach a sophisticated CE. Similarly, circular practices that go beyond recycling require a strong motivation, either through integration in the focal firm´s quality commitment or through business model recognition. It is further suggested that the circular design of products and services could reduce necessary transaction costs and thus overall costs of a circular economy. Four different integration strategies for circular economy practices have been derived from the conducted case studies. These are: 1) vertically integrated loops, 2) cooperative loop-networks, 3) outsourcing to loop operators and 4) independent loop operators. This work thus provides evidence that circular economy activities do not necessarily have to be managed by focal actors in the value chain. Rather, circular practices can also be put forward by specialized loop operators or even independent actors such as repair shops.
In der Forschungsarbeit wird ein Rahmenmodell von Kompetenzen nachhaltigkeitsorientierter Verwaltungsführung in Kommunen und ihrer Förderung entwickelt und beschrieben. Methodische Grundlage hierfür bilden eine systematische Literaturrecherche sowie 25 qualitative, leitfadengestützte Interviews mit 13 verwaltungsexternen und 12 verwaltungsinternen Experten aus drei Fallstädten (Freiburg, Wernigerode, Ludwigsburg). Übergeordnetes Ziel des Modells ist der Auf- bzw. Ausbau nachhaltigkeitsorientierter Prozesse in Kommunalverwaltungen, um nachhaltige Entwicklung auf lokaler Ebene insgesamt zu fördern. Aufbauend auf dem Managementmodell Mintzbergs und drei Sustainable-Leadership-Modellen werden hierfür nachhaltigkeitsorientierte Handlungsbereiche von Oberbürgermeistern, Beigeordneten und Fach- bzw. Amtsleitungen im Verwaltungsalltag aufgezeigt. Ob bzw. inwieweit diese Handlungsmöglichkeiten genutzt werden, hängt unter anderem von der Ausprägung zentraler Kompetenzen nachhaltigkeitsorientierter kommunaler Verwaltungsführung ab. Diese werden u. a. basierend auf Ansätzen von Nachhaltigkeitskompetenzen für Führungspersonen aus der Privatwirtschaft herausgearbeitet. Ferner werden Förderungsmöglichkeiten solcher Kompetenzen in Aus- und Fortbildung sowie in der Organisationsentwicklung und im kommunalen Personalmanagement hergeleitet und beschrieben. Potentielle konkrete Förderungsmethoden werden ebenfalls untersucht.
Die Arbeit liefert die Grundlagen zur chemischen Entfernung von Biodiesel aus dem Motoröl, um eine Minderung der Einschleppungsproblematiken beim Einsatz von biogenen Kraftstoffen und Dieselpartikelfiltern zu erzielen. Das Prinzip beruht auf einer wechselwirkenden Beimischkomponenten die eine Azeotropbildung mit Biodiesel einleitet. Eine gaschromatographische Headspace-Screening-Methode diente der Messung von Aktivitätskoeffizienten in Anwesenheit von Biodiesel. Die Ergebnisse dieser Analysen lieferten erste Erkenntnisse welche funktionalen Gruppen eine notwendige starke Wechselwirkung mit Biodiesel besitzen. Die gaschromatographischen Analysen wurden zudem mit Simulationsrechnungen mittels COSMOtherm untermauert. Im Laborversuch haben sich polare Säuren wie Ameisensäure oder Essigsäure als gute Beimischkomponenten erwiesen. Aldehyde, Ketone oder Alkohole sind weniger geeignet. Säuren wirken als Hydrogen Bond Donator und besitzen hohe Aktivitätskoeffizienten mit Biodiesel. Durch die Destillation des gebildeten azeotropen Gemischs kann die Entfernung von Biodiesel aus dem Motoröl bei niedrigen Temperaturen von ca. 180 Grad Celsius bis 190 Grad Celsius realisiert werden. Ohne den Einsatz von Beimischkomponenten liegt die Destillationstemperatur von Biodiesel bei ca. 330 Grad Celsius.
The dissertation project focuses on empirically investigating consumers' attitudes, motivations and purchasing decisions regarding sustainable products. The focus on this micro perspective, however, does not reflect consumers' roles within the transformation towards sustainable consumption. Therefore, the present framework paper puts the included papers into a greater context and evaluates the findings on a meta-level by applying an enhanced transition management theory. The analysis underlines that consumers' limited personal capabilities are an underlying reason for unsustainable practices. Therefore, the active engagement not only of consumers, but also of companies is required if the transformation is to be successful. If companies actively support consumers in making sustainable choices, consumers can engage in sustainable consumption with only low cognitive efforts. On this basis, genuine sustainable choices are enabled. The dissertation provides practical implications by highlighting potential measures which will help to promote sustainable products from niches to mainstream. In sum, the dissertation project enhances academic understanding of consumers´ sustainable purchasing behavior and reveals the potential of integrating such insights into the management of transformations towards sustainable consumption.
A solid knowledge about nature is essential to understand the consequences of biodiversity loss, the limitation of natural resources and the need for a sustainable development. Inspired by these challenges, the researcher investigated in her dissertation seed predation, an important ecosystem function, as part of citizen science project. As seed predation has only rarely been investigated along urban-rural gradients and to integrate the question if the background (urban vs. rural) of primary school children affects their environmental knowledge, she selected study sites in and around Lüneburg and Hamburg, in Northern Germany. In her ecological experiments, it was found that slugs are important seed predators that independently of urbanization predated about 30% of all seeds in the anthropogenically used landscapes investigated. Also, for the first time, primary school children could be integrated in a citizen science approach into this research and it could be shown that even seven year old children can record data as reliable as a scientist. Finally, the researcher investigated the native species knowledge from the children taking part as citizen scientists in her research, considering possible differences due to their urban or rural background. Contrary to her expectation, the urban or rural background had no significant effect on the species knowledge. However, the work provides a good foundation to transfer the approach of introducing a basic foundation of a taxonomical species concept in primary school to foster further understanding on biodiversity and ecosystem functions.
Das ubiquitäre Vorkommen von Arzneimittelrückständen ist eng mit möglichen Risiken für Mensch und Umwelt verbunden. Das übergeordnete Ziel dieser Forschungsarbeit ist die Weiterentwicklung methodischer Ansätze für die Identifizierung prioritärer Arzneimittelrückstände vor dem Hintergrund bestehender Wissens- und Regulierungslücken. Unter diesem Gesichtspunkt wurden drei aktuelle Problemfelder aus dem Themenkomplex "Arzneimittel in der Umwelt " ausgewählt und anhand konkreter Fallbeispiele betrachtet. Tierarzneimittel werden häufig mit der Ausbringung von Wirtschaftsdünger in landwirtschaftlich genutzte Böden eingetragen. Gegenstand der ersten Publikation ist die Frage, inwiefern Anwendungsschemata aus der Nutztierhaltung für die retrospektive Identifizierung prioritärer Tierarzneimittelrückstände genutzt werden können. Hierzu wurde eine spezielle Herangehensweise entwickelt und am Beispiel von Antibiotika erprobt. Die durchgeführte Eintragsabschätzung ermöglichte erstmalig eine umfassende Einschätzung der potenziellen Antibiotikabelastung in Wirtschaftsdünger und landwirtschaftlich genutzten Böden im nordwestdeutschen Raum. Die Ergebnisse deuten auf erhebliche Umwelteinträge hin, die eine Neubewertung bestehender Wirkstoffzulassungen notwendig erscheinen lassen. In der zweiten Publikation wurden am Beispiel einer Mischung aus 18 Arzneistoffen verschiedene Bewertungsansätze verfolgt, um das Risiko einer kombinierten antimikrobiellen Wirkung genauer zu charakterisieren und prioritäre Mischungsbestandteile zu identifizieren. Das Risiko einer antimikrobiellen Wirkung wurde sowohl durch eine experimentelle Prüfung der Mischung als auch durch einen komponentenbasierten Berechnungsansatz bestätigt. Der komponentenbasierte Ansatz verdeutlichte zudem die besondere Relevanz der in der Mischung enthaltenen Fluorchinolon-Antibiotika. Die notwendige Grundlage für eine belastbare Abschätzung von Kombinationseffekten sind jedoch harmonisierte Einzelstoffdaten, die bisher nicht im benötigten Umfang zur Verfügung stehen. Deshalb sollte speziell für Antibiotika eine systematische Prüfung der Wirkung auf Umweltmikroorganismen durchgeführt werden. Arzneistoffe können entlang ihres Lebenszyklus verschiedene biotische und abiotische Transformationsprozesse durchlaufen, die oft zur Bildung von unvollständig charakterisierten Transformationsprodukten (TPs) führen. Die Publikationen 3-7 leisten einen allgemeinen Beitrag zur Einschätzung des möglichen Gefahrenpotenzials von pharmazeutischen TPs im Wasserkreislauf und generieren neue methodische Erkenntnisse vor dem Hintergrund einer vorausschauenden Identifizierung von prioritären Abbauprodukten. Die durchgeführten Fallstudien bestätigten, dass photochemische Transformationsprozesse nicht nur zur Abschwächung bereits vorhandener, sondern im Gegenteil auch zur Entstehung gänzlich neuer Gefahrenpotenziale beitragen können. Es ist somit stark in Frage zu stellen, ob die alleinige Fokussierung auf bekannte Aktivitäten der Muttersubstanz für eine sichere Bewertung von TPs ausreicht.
The effects of habitat fragmentation and land use changes are usually studied by relating patterns of genetic diversity and differentiation to environmental factors, habitat history, landscape structure, or to a combination thereof. However, these three drivers are rarely addressed simultaneously. In addition, these studies are usually carried out in conservation-driven contexts, and therefore tend to concentrate on hyper-fragmented landscapes and on rare or endangered species. However, how habitat fragmentation and land use affect widespread species in more typical landscapes has not been fully investigated. This thesis addresses these two gaps. Abax parallelepipedus, a flightless ground beetle with low dispersal power, was used as a model species to test how environmental factors, habitat history, and landscape structure affect genetic diversity and genetic differentiation in three study regions located across Germany. Although all of the study regions represent fairly typical rural landscapes for central Europe, each consisting of a complex matrix of land uses, they differ from one another in terms of environmental factors, habitat history, and landscape structure, and thus can serve as three test cases. In the first stage of the work, the investigator identified polymorphic microsatellite loci which could potentially be used to study genetic diversity and differentiation in A. parallelepipedus. She then developed PCR and genotyping protocols for two suites of loci, in the end selecting to use the set of 14 fully multiplexed loci for the study. After having developed the needed study system, she genotyped over 3300 beetles from 142 study sites. In her investigation of how environmental factors and habitat history affect genetic diversity and genetic differentiation, and found that genetic diversity was being driven by variables that could be related to population sizes rather than by habitat history. She also did not find evidence of an influence of habitat history on the genetic differentiation patterns. Although populations of A. parallelepipedus in the past were probably smaller due to deforestation, they apparently remained large enough to prevent rapid genetic drift. In addition, the researcher carried out a landscape genetics analysis of the genetic differentiation patterns found in each of her study regions, in which she examined the relationship between genetic differentiation and landscape structure. She tested whether she could find patterns of isolation by distance, isolation by resistance, or isolation by barriers in the study regions. No effects of land use or of fragmentation were found. Based on the importance of population sizes found in the previous study, combined with the beetle's known avoidance of non-wooded areas and its inability to cross roads, the investigator concludes that although there is probably little gene flow across the study regions, large population sizes are preventing the rapid development of genetic differentiation. Models simulating the development of genetic differentiation over time in populations of different starting sizes support this conclusion.