Open Access

Die Agenda 2030 der Vereinten Nationen und diverse daraus abgeleitete Nachhaltigkeitsstrategien wie beispielsweise die Deutsche Nachhaltigkeitsstrategie (Neuauflage 2016) setzen einen zeitlich fest definierten Rahmen bis in das Jahr 2030. Für die Umsetzung dieser Strategien sind zwei Aspekte entscheidend - ein fundiertes inhaltliches Verständnis von politischer Strategie und ein darauf aufbauendes praxistaugliches Instrument, das den politischen Strategen bei einer erfolgreichen Umsetzung und Implementierung einer Strategie unterstützt. Diese Arbeit möchte zu beiden Aspekten einen Beitrag leisten. Zum einen soll aus der Zusammenführung von Theorie und Praxis die Natur des inhaltlichen politischen Strategiebegriffs erforscht werden und zum anderen soll darauf aufbauend ein praxis- und erfahrungsorientiertes Anwendungsmodell entwickelt werden, das typische potentielle Herausforderungen und entsprechende potentielle Handlungsoptionen je Strategieabschnitt benennt. Durch die Subsumierung von Erfahrungswissen unterstützt das Modell dabei vor allem das praktische Urteilsvermögen des politischen Strategen bei der Erreichung politikstrategischer Ziele. Um zu dem praxisrelevanten Anwendungsmodell zu gelangen ist es notwendig, sich zuvor Klarheit über die besonderen Anforderungen und Herausforderungen des speziellen politischen Strategiebegriffs zu verschaffen. Die politische Umwelt mit ihren spezifischen Mechanismen unterscheidet sich fundamental von den bisher bekannten Strategiefeldern Militär und Betriebswirtschaft. Da eine Strategie immer die konkrete Umweltsituation und die individuellen Situationsmerkmale berücksichtigen muss, ist - wie diese Arbeit zeigen wird - eine simple Übertragung strategischer Allgemeinplätze aus Militär und Ökonomie von vornherein zum Scheitern verurteilt.

The aim of our work was to investigate the habitat preferences of, and specific management measures for, the endangered spider species Eresus kollari Rossi 1846 and the eurytopic species Trochosa terricola Thorell 1856. For this purpose extensive field study data were collected for both spider species in the area of the nature reserve Lueneburg Heath. The ecological niches of the two spider species were also compared. The specific habitat preference of E. kollari was clarified and described in the course of the present studies. Heathland management measures that result in a thin organic layer on the ground, a high temperature at the depth of the spiders’ burrows (10 cm below ground level), and at the same time a relatively high heath cover satisfy the habitat requirements of E. kollari. Comparing the ecological niche of the stenotopic species E. kollari with that of the eurytopic species T. terricola in terms of habitat parameters demonstrated that the two species only differ in the following three factors: ‘tree cover’, ‘thickness of organic layer’ and ‘grass cover’. The reaction scheme of E. kollari appears as a subset of that of T. terricola. In this respect, E. kollari could serve not only as a characteristic species but also as an umbrella species in the Lueneburg Heath region. Against the background of the findings of the habitat modeling, management measures such as prescribed burning and choppering - carried out variably in space and time – seem to be particularly appropriate for maintaining E. kollari’s (but also T. terricola’s) microhabitat requirements in the long term. Due to the poor dispersal power of E. kollari some suitable habitats will probably not be re-colonized by the species. However, long-term monitoring as well as a recolonization experiment for this species should be carried out in the near future in areas providing suitable conditions for lasting conservation of E. kollari in this region of northwest Germany.

Algae-bacteria-based biotechnology has received more and more attention in recent years, especially in the subtropical and tropical regions, as an alternative method of conventional multistep wastewater treatment processes. Moreover, the algal biomass generated during wastewater treatment is regarded as a sustainable bioresource which could be used for producing biofuel, agricultural fertilizers or animal feeds. Although this technology is attractive, a number of obstacles need to be solved before large-scale applications. The main purposes of this work are to find more effective biomass harvesting strategies and develop high-effective algal-bacterial systems to improve wastewater treatment performance, biomass generation rate and biomass settleability. A wastewater-borne algal-bacterial culture, cultivated and trained through alternate mixing and non-mixing strategy, was used to treat pretreated municipal wastewater. After one month cultivation and training, the acclimatized algal-bacterial system showed high carbon and nutrient removal capacity and good settleability within 20 minutes of sedimentation. Algal biomass uptake was the main removal mechanism of nitrogen and phosphorus. The biomass productivity, nitrogen and phosphorus accumulation in biomass during the wastewater treatment process were investigated. The characterization of the microbial consortium composition in the enriched algal-bacterial system provided new insights in this research field. Aerobic activated sludge which already showed good settleability was used as bacterial inoculum to enhance the wastewater treatment performance and biomass settleability of algal-bacterial culture. The influence of different algae and sludge inoculum ratios on the treatment efficiency and biomass settleability was investigated. There was no significant effect of the inoculation ratios on the chemical oxygen demand (COD) removal. But algae/sludge inoculum ratio of 5 showed the best nitrogen and phosphorus removal efficiencies (91.0 ± 7.0% and 93.5 ± 2.5%, respectively) within 10 days. Furthermore, 16S rDNA gene analysis showed that the bacterial communities were varying with different algae and sludge inoculation ratios and some specific bacteria species were enriched during the operation. Four commonly used and high-potential microalgae species including one cyanobacteria (Phormidium sp.) and three green microalgae species (Chlamydomonas reinhardtii, Chlorella vulgaris and Scenedesmus rubescens) were cultivated and trained through alternate mixing and non-mixing strategy for tertiary municipal wastewater treatment. After one month of cultivation, the four microalgae species were compared in terms of biomass settleability, nutrient removal rates and biomass productivity. The three green microalgae showed good settleability within 1 h sedimentation and had higher biomass generation rates (above 6 g/m2/d). The nutrient removal efficiencies were 99% for the four selected microalgae species but within different retention time, resulting in 3.66 ± 0.17, 6.39 ± 0.20, 4.39 ± 0.06 and 4.31 ± 0.18 mg N/l/d (N removal rate) and 0.56 ± 0.07, 0.89 ± 0.05, 0.76 ± 0.09 and 0.60 ± 0.05 mg P/l/d (P removal rate) for Phormidium sp., Chlamydomonas reinhardtii, Chlorella vulgaris and Scenedesmus rubescens, respectively. A mixed algal culture composed of three selected high-effective green microalgae (Chlamydomonas reinhardtii, Chlorella vulgaris and Scenedesmus rubescens) was used for tertiary municipal wastewater treatment. The key biotic factor (algal inoculum concentration) and abiotic factors such as illumination cycle, mixing velocity and nutrient strength were studied. Based on the nitrogen and phosphorus balance, it was found that assimilation into algal biomass was the main removal mechanism.

Human activities have converted natural ecosystems worldwide, mostly for agricultural purposes. This change in land use has been recognized as one of the key drivers causing mass extinction of biodiversity. Yet, there are species which persist particularly in traditional, low-intensity agricultural areas. However, this farmland biodiversity is increasingly threatened by the consequences of land-use intensification and land abandonment. One effect of these two processes is the change in existing landscape structures. This dissertation aimed at quantifying the relationship between biodiversity and landscape structures because a better understanding of current biodiversity patterns and their drivers is needed to navigate biodiversity conservation for a sustainable development. Specifically, this dissertation anticipates the impacts of land-use change on biodiversity in Southern Transylvania, focusing on butterflies and plants as study groups. In a first step, a methodological baseline for subsequent biodiversity studies is developed by exploring an optimal survey strategy, allocating the available resources in a study design that enables high statistical power and covers a wide range of environmental conditions. This study shows that in the highly heterogeneous farmland mosaic of Southern Transylvania, survey effort can be moderately reduced while still showing similar patterns of species richness, species turnover and species composition (Chapter 2). In a second step, biodiversity patterns of plants and butterflies are empirically investigated in response to different landscape structures, particularly towards heterogeneity and woody vegetation cover. These studies provide evidence that all main land-use types in Southern Transylvania, namely arable land, grassland and forests, contribute to an overall landscape pool. Species richness of plants, but not of butterflies, differed significantly between arable land and grassland. Presence of woody vegetation in farmland had a positive effect on plant species richness. Heterogeneity has been found beneficial for butterfly species richness in arable land, but not in grasslands. Species composition of plants was determined by land-use, but butterfly species composition was widely overlapping in arable land and grassland (Chapters 3 & 4). Investigations on the potential spread of invasive plant species in the Transylvanian landscape exhibited that distance to roads and heterogeneity, especially in arable land, were key variables determining the invasibility of the landscape (Chapter 5). By studying movement patterns of butterflies in agricultural landscapes, land-use intensity could be revealed having an impact on butterfly movements. Furthermore, butterflies were found to prefer non-arable patches within farmland (Chapter 6). In a third step, this dissertation conceptually embeds socio-economic considerations into the local and international discourse on sustainable rural development: Reflections on a participatory projects on establishing butterfly monitoring in Romania conclude that involving citizens in biodiversity conservation is possible in Romania, but need tailored approaches which consider the unique social and cultural settings (Chapter 7). Current recommendations from scientific literature to increase the agricultural yield, for example in Eastern European landscapes, through ´sustainable intensification´ for global food security are scrutinized for their engagement with sustainability. This dissertation concludes that genuine sustainable solutions need to respect the various aspects of sustainability, including procedural and distributive justice. Furthermore, it is clarified that general recommendations for agricultural intensification, for instance in Romania, may lead to devastating impacts on biodiversity and ecosystem functions (Chapter 8). This dissertation provides evidence that the beneficial characteristics of the Translvanian farmland are linked to the fine spatial scale of the agricultural mosaic, the amount and distribution of semi-natural elements and the scattered woody vegetation throughout the landscape. Hence, the future of biodiversity depends on human interventions in the ancient cultural landscape. Navigating biodiversity conservation in Southern Transylvania thus needs genuine sustainable solutions, which integrate socially acceptable and ecological meaningful landscape management.

In spite of growing interest in companies’ contribution to sustainable development, the implementation of corporate sustainability, i.e. the integration of environmental, social, and economic issues, is not well understood. This cumulative PhD thesis aims to answer the research question whether sustainability management is only a transitory management fashion, or whether an effective implementation is actually taking place. The thesis consists of five papers, which are either published in refereed academic journals, accepted to be published, or planned to be resubmitted. The papers analyze three important elements of the implementation of corporate sustainability: motivation (why?), organizational units (who?) and management tools (how?). Combining these three elements supplies a framework for discussing the implementation of corporate sustainability management. The results, which are mostly based on surveys of large German companies, reveal that companies predominantly manage corporate sustainability because they seek legitimacy, rather than a competitive advantage, and because they follow acknowledged standards, guidelines, or ratings (institutional isomorphism) – possibly out of uncertainty on how to best handle a concept so complex and novel. Public relations is the organizational unit engaging in sustainability management most strongly, whereas accounting, finance, and management control engage the least. Hence, corporate sustainability is currently not implemented as a crossfunctional approach. Yet, there is indication of a growing strategic relevance of corporate sustainability. This is also reflected in the awareness and application of sustainability management tools, which have been increasing continuously between 2002 and 2010 – especially in terms of integrative tools serving to balance environmental, social, and economic issues. Furthermore, market incentives are gaining in importance over time. The thesis relates these results to management fashion theory. Although there is some indication that sustainability management might in fact be a transitory fashion, an analysis over time reveals an ongoing development of the elements analyzed. Thereby, the thesis demonstrates that corporate sustainability management can be considered more than a management fashion. One implication of the analysis is that both companies and researchers are called upon to foster the implementation of corporate sustainability, with positive incentives, e.g. by markets and consumers, turning out to be promising starting points. As opposed to pressure and expectations by stakeholders, focusing on opportunities might be more suitable to induce actual change of processes, products, services, or even business models in companies. In conclusion, the author hopes to make a significant contribution to the discussion on the implementation of corporate sustainability and to stimulate the development of new theoretical approaches.

Der Klimawandel wird die Gesellschaft in Zukunft immer stärker beeinflussen. In der Arbeit wird untersucht, wie die direkten Auswirkungen und die daran anschließenden Klimaschutz- und Anpassungsmaßnahmen regionale Konfliktsituationen verändern können. Untersucht werden bisherige Konflikte des Tourismussektors mit anderen nicht-touristischen Akteursgruppen sowie mögliche Konfliktpotenziale durch den Klimawandel am Beispiel der Destinationen Schwarzwald und schleswig-holsteinische Nordseeküste. Qualitative Experteninterviews geben Hinweise darauf, dass besonders die Mitigations- und Anpassungsmaßnahmen, die sonst eher als Konfliktlösung eine Rolle spielen, ein bedeutendes und bisher unterschätztes Konfliktpotenzial bergen. Formelle Verfahren, aber auch eine zusätzliche informelle Beteiligung werden von den Akteuren vor Ort als Konfliktregelungsmechanismen befürwortet.

Auf Grund der stetig wachsenden Menge an Daten gewinnt die automatische Datenanalyse durch Algorithmen zunehmend an Bedeutung. Im Speziellen trägt die Analyse von Texten ohne manuelles Zutun zu einer erhebliche Erleichterung der Extraktion von relevanten Informationen bei. Sprachliche Informationen können neben der Zuordnung zu Kategorien auf Regeln und Muster untersucht werden. Diese Art der Untersuchung fällt in den Bereich des Text Minings und in der vorliegenden Arbeit geht es darum, eine qualitative Inhaltsanalyse zum Thema Nachhaltigkeit nachzuempfinden. Es soll geprüft werden, in wie weit automatisierte Verfahren in der Lage sind, Ergebnisse einer bereits bestehenden Untersuchung zu erzielen. In der Durchführung werden mit der OpenSource Software RapidMiner vier Prozesse erstellt, die darauf abzielen, Zeitungsartikel auf ihren Inhalt zu analysieren. Unter anderem werden eine Assoziationsanalyse und eine Klassifikation realisiert, deren Ziel es ist, den Kontext und die Verwendung des Begriffes der Nachhaltigkeit in den Medien zu untersuchen. Die vorliegende Studie will prüfen, ob automatisierten Methoden im Vergleich zu manuellen Verfahren hinreichende Ergebnisse liefern können, sodass die hiesigen Resultate an denen der zu Grunde gelegten Studie von Fischer und Haucke gemessen werden sollen. Die Ergebnisse zeigen, dass die Realisierung einer Inhaltsanalyse mit RapidMiner möglich ist und zu erheblichen Zeiteinsparungen gegenüber konventionellen Verfahren führt. Sie zeigen jedoch auch, dass sich die Minderung des Aufwandes in der Ergebnisqualität widerspiegelt und somit der alleinige Einsatz von Text Mining Verfahren zur Analyse von spezifischen Kontexten noch nicht ausreichend ist.