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Soil organic carbon (SOC) is the largest terrestrial carbon pool, holding a manifold of atmospheric carbon. The agricultural management of soils exerts a strong influence on this pool and thereby also on carbon fluxes between biosphere and atmosphere. Historically, land-use changes have caused large CO2 emissions from soils, which significantly contributed to global warming. The latter is expected to cause strong fluxes of CO2 from soils, due to enhanced microbial activity – the climate-carbon cycle feedback loop. This cumulative habilitation thesis focuses on the two major anthropogenic impacts on soil organic carbon as the largest terrestrial carbon pool: land use and global warming due to greenhouse gas emissions. Both have been steadily increasing with the expansion of human population and activity on the planet and are thus considered specific for the ‘Anthropocene’ as a synonym for the period in world history in which human activity leaves irreversible traces. Due to the importance of SOC and its management for climate change, but also for soil fertility and ecosystem resilience, it is crucial to understand i) which management options can maintain and increase SOC, ii) what are the mechanisms leading to SOC losses and stabilization, iii) how shall global net primary production (NPP) as a resource be used in a climate-smart and sustainable way, iv) how will global warming affect SOC dynamics. Together with several methodological aspects related to measuring, calculating and modelling SOC, the research presented in this thesis focuses on those four key questions.
Böden sind die Lebensgrundlage des Menschen und anderer Organismen. Ungeachtet dessen findet weltweit eine Zerstörung dieser nicht erneuerbaren Ressource statt, wodurch der Mensch diese Lebensgrundlage immer weiter degradiert. Das Konzept der Ecosystem Services (Ökosystemleistungen) soll dazu beitragen, die weltweite Zerstörung von Ökosystemen einzudämmen, indem die Leistungen der Natur sowie deren Verlust erfasst, bewertet und damit auch für Entscheidungsträger/innen sichtbar werden. Das Umweltmedium Boden, in dem sich unterschiedliche Sphären des Ökosystems überschneiden und vielfältige Wechselwirkungen und Prozesse stattfinden, bietet essenzielle Beiträge zu vielen Ökosystemleistungen. In vielen Studien werden diese Beiträge jedoch nur unzureichend betrachtet, sodass die vielfältigen Leistungen der Böden im Verborgenen bleiben.
In der vorliegenden Arbeit wird beispielhaft für den Nationalpark Asinara (Sardinien) aufgezeigt, wie die Beiträge der Böden zu Ökosystemleistungen erfasst, bewertet und damit in ihrer Bedeutung sichtbar gemacht werden können. Hierzu wird ein übertragbares, auf feldbodenkundlichen Aufnahmen und physikochemischen Laboruntersuchungen aufbauendes Bewertungsschema für bereitstellende, regulierende und kulturelle Boden-Ökosystemleistungen entworfen. Eine Monetarisierung der Leistungen wird nicht angestrebt. Mit bodengeographischen Modellen und Methoden der digitalen Bodenkartierung wird ein Bodeninformationssystem aufgebaut, auf dessen Grundlage das Bewertungsschema für das Untersuchungsgebiet umgesetzt wird. In der faktorenbasierten Vorgehensweise wird die deutlich reliefabhängige Bodenverbreitung durch eine hochauflösende digitale Reliefanalyse abgebildet. Vegetationsökologische Ergebnisse werden einbezogen, um mit Fernerkundungsmethoden eine digitale Landbedeckungskartierung umzusetzen. Zudem wird eine Analyse der historischen Landnutzung vorgenommen, um die im Gelände erfasste anthropogene Veränderung der Böden flächenhaft abzubilden und kulturelle Boden-Ökosystemleistungen zu visualisieren. Es erfolgt eine Betrachtung der raumzeitlichen Veränderungen der Inanspruchnahme von Boden-Ökosystemleistungen auf der mediterranen Nationalparkinsel. Mit den Bodeninformationen wird ein hochauflösender Beitrag zum Management des Schutzgebietes bereitgestellt, welcher zur Planung von Management- und Renaturierungsmaßnahmen sowie zur Durchführung von Habitatanalysen herangezogen werden kann. Zur Förderung des Transfers von Boden-Ökosystemleistungen in Planungs- und Entscheidungsprozesse und zur Sicherung einer nicht-anthropozentrischen Perspektive wird ein Huckepackverfahren vorgeschlagen, in welchem eine Bodenfunktionsbewertung die Grundlage für die Ausweisung von Boden-Ökosystemleistungen bildet. Mit einem breiten interdisziplinären Ansatz dokumentiert das Fallbeispiel für die mediterrane Landschaft ausgehend von Primärdatenerhebungen erstmals den vollständigen Erarbeitungsprozess einer hochauflösenden Bewertung aller Kategorien von Boden-Ökosystemleistungen im regionalen Maßstab. Die Ergebnisse verdeutlichen das erhebliche Potenzial der digitalen Kartierungsverfahren, unterstreichen aber auch die Notwendigkeit eines Mindestmaßes an Geländeuntersuchungen, insbesondere zur Erfassung der kulturellen Leistungen von Böden.
Dieses Zine ist ein kreatives Kleinstmagazin mit Bildern, Text und jeder Menge Gedanken, die wir uns im Laufe des Wintersemesters 2020/21 zum Thema Klimagerechtigkeit gemacht haben.
Aber was genau soll das sein, ein Zine? Ein Magazin, eine Dokumentation unserer Diskussion und Lektüre? Ehrlich gesagt haben wir uns einfach gewünscht, nicht schon wieder eine Hausarbeit für die Schublade zu schreiben, und in diesen distanzierten Zeiten mit dir da draußen im Netz Kontakt aufzunehmen; zu überlegen, wie man die Inhalte und kritische Lektüre auch auf anderen Wegen vermitteln und verständlich machen kann.
Das Thema ist dringlich und es ist komplex, verwoben und verschränkt. Das zeigt auch das Manifest zur Klimagerechtigkeits- und Nachhaltigkeitsbildung, das ebenfalls in unserem Seminar entstanden ist und welches du als Abschluss dieses Zines findest.
Lass dich inspirieren, lass dich irritieren, werde aktiv – und lass uns die Welt gemeinsam ein wenig gerechter machen!
Madagascar is a biodiversity hotspot under threat, with about 80% of the population living below the poverty line and dependent on the use of diminishing local resources. Environmental education (EE) can act as an important tool for biodiversity conservation, however, its implementation is challenging in low-income countries. Here, we provide a review of 248 EE interventions throughout Madagascar. We highlight how EE can promote pro-environmental behaviors and show the major obstacles it faces, using Madagascar’s Lake Alaotra as a case study area. All EE activities are implemented by non-governmental organizations (NGOs) and international institutions. EE and community engagement have been shown by practitioners and scientific research alike to be valuable tools but are severely restricted in their impact when their outreach is limited by insecure and insufficient funding, and often funding periods that are too short. Another major hindrance to EE producing positive changes in people’s real-life decisions in low-income countries like Madagascar, arises when lessons are taught to a population that is at once understanding and severely constrained in its choices due to poverty, and corresponding malnutrition, that forces people to make unsustainable decisions on a daily basis. Our conclusions should help to improve the practice of EE in Madagascar and other low-income countries.
In this paper, we present the results of a survey of an environmental education program applied to a cohort of 542 students in six primary schools at Lake Alaotra, Madagascar. The educational materials used were a comic book and additional materials designed specifically for local conditions in rural Madagascar. The comic book conveyed mostly system knowledge and, to a lesser extent, action-related knowledge. The additional materials posed practical tasks to students and were meant to stimulate teamwork and group discussion of students. There was a control and two treatment groups. A questionnaire was applied to test students’ environmental knowledge at three different points in time. The survey showed a significant increase in environmental knowledge of students receiving environmental education compared to controls. This effect significantly increased with additional education materials fostering peer-to-peer learning by students instead of when teacher-centred learning was provided. Students that used those materials also had the highest scores in tests one year after environmental education ended, thus indicating the usefulness of innovative and locally meaningful materials in environmental education.
From Safety Net to Point of No Return—Are Small-Scale Inland Fisheries Reaching Their Limits?
(2020)
Small-scale inland fisheries (SSIF) are a livelihood opportunity for millions of people in developing countries. Understanding the economic, ecological, political and social impacts fishers are coping with can clarify weaknesses and challenges in the fishery management. Using the SSIF at Lake Alaotra, Madagascar, as an example, we analyzed the development and fishers’ perception of, and adaptation strategies to, change. We surveyed fish catches to assess the state of fish stocks and conducted interviews to understand fishers’ livelihood, problems, behavior and attitudes. Our results show that the fishery sector of Lake Alaotra has grown dramatically although fish catches have fallen sharply. Changes in species composition and low reproduction rates reflect the fishing pressure. A point of no return seems near, as decreasing agricultural yields force farmers to enter the fishery sector as a form of livelihood diversification. Lake Alaotra reflects an alarming trend which can already be seen in many regions of the world and may affect a growing number in the near future. The Alaotran fisheries demonstrate that SSIF’s ability to provide livelihood alternatives under conditions of insecurity will become increasingly important. It further highlights that the identification of ongoing livelihood dynamics in order to disclose possible poverty trap mechanisms and to understand fisheries’ current function is essential for sustainable management.
Based on the indeterminate character of the sustainability concept, a procedural and discursive understanding of sustainability decision making and corresponding approaches for education for sustainability (EFS) is proposed. A set of criteria for teaching strategies to promote sustainability decision making, taking into account the demands of deliberative democracy theory, are presented. These criteria (such as reason, complexity management, critical thinking, etc.) are used to argue for an educational approach that involves the development, justification, and weighting of arguments in combination with an instructional tool called Target-Mat. According to a consequent process orientation, structures for arguing or defining sustainability are not given as authorized standards. Suggestions from previous social discourse are only introduced as controversial pairings—for example, different definitions of sustainability. Examples of student decision-making processes are given to demonstrate the potential of the approach to encourage student reflection and cooperative negotiation that engenders a successive deepening of their argumentation.
Tropical wetlands maintain a high biodiversity and provide ecological services which are basis for millions of livelihoods. However, freshwater ecosystems are largely neglected in research and environmental policy. Today they are among the most threatened habitat types throughout the world with highest loss rates for natural inland wetlands in the tropics. The high dependency of local communities upon natural resources makes conservation management for wetlands in developing countries to a particular challenge.
This study investigated the different perspectives of conservation planning at Lake Alaotra, the largest wetland complex of Madagascar. First, the ecological state of Lake Alaotra was assessed to close knowledge gaps and to provide an adequate basis for ecosystem-based conservation measures. Second, I evaluated the community-led management of a small protected area in order to determine its potentials and weaknesses. Third, the local fishery, as the largest lake resource user group, was investigated to understand the drivers of overfishing.
By interlinking the results of the three perspectives of conservation planning – ecology, management and resource user – interrelations and trade-offs between the three dimensions were identified. The current ecological state of Lake Alaotra reveals that the anthropogenic disturbance is favoring the proliferation of invasive plant species and leading to the alteration of the water quality (e. g. hypoxia). Insights into the local management show that the community-based management contributes to the conservation of the natural flora and fauna. However, the small-scale conservation area suffers from isolation and illegal activities, while its management lacks recognition at community level. The fishery sector has grown dramatically although fish catches have fallen sharply. Species composition changes and low reproduction rates are reflecting the fishing pressure. A high population growth and lacking agricultural land force people to enter fishery and increases the human pressure on the lake.
Overall this study shows that the conservation of multiple-value ecosystems, such as tropical wetlands in developing countries, require site-specific multidimensional approaches that interlink ecological demands, resource user needs and the local sociocultural setting. This research demonstrates that: ongoing livelihood dynamics linked to the socio-economic conditions have to be considered to create more realistic management policies; strengthening resource users’ assets will help to decrease the human pressure on the already considerably altered ecosystem; capacity building for local management associations and the adoption of local ideas and management concepts is needed to enable the evolvement of an locally legitimated and tailored wetland conservation management.
The study of vegetation-plot data on a broad geographical scale is of increasing importance in vegetation science. It significantly contributes to the transnational characterisation of vegetation types as well as the better understanding of their large-scale patterns and to habitat typologies, which are important for decision-making processes in European nature conservation.
I examined semi-natural, saline and brackish Baltic Sea grasslands which occur on sedimentary flats at the transition between land and sea. Their diverse vegetation is dependent on low intensity grazing (Dijkema 1990). This valuable part of the European cultural landscape (Küster 2004), which is recognized as Annex I priority habitat type (Natura 2000; European Commission 2013), underwent an overall decrease in quality and quantity within the last 150 years, which is frequently related to abandonment. Thus, the coastal grasslands of the Baltic Sea have been assessed as Endangered in the European Red List of Habitats (Janssen et al. 2016).
Within this thesis I (i) developed a proposal to integrate vegetation data using non-standard scales into general vegetation analyses, (ii) characterised the vegetation of Baltic Sea grasslands on transnational level, (iii) regarded them from a North-west European perspective, (iv) discussed their nature conservation aspects on European scale, (v) investigated changes in their plant species composition and discussed its possible relation to cessation of grazing and (vi) formulated a monitoring concept important for management planning in nature conservation.
Grazing animals alter natural processes by affecting ecosystems and at the same time fulfilling ecosystem functions, thus they are regarded as ecosystem engineers. Effects of grazing are mainly studied in managed systems, where grazing animals are restricted in their movement and thus limited to certain vegetation types. On the island of Asinara the grazing system is now, due to its history as agro-penitentiary, a natural grazing system with donkeys, horses, goats, mouflons and wild boars. This multitude of grazers poses a challenge for the Asinara National Park and its management. Therefore this dissertation takes an interdisciplinary approach to investigate grazing animals and their interrelations with different components of the island ecosystem to analyse their role on the island and evaluate their effects on the biodiversity. The composition and distribution patterns of the five grazing animal species have been investigated in the context of the land-cover types of the island ecosystem. In addition, the input on the vegetation through endozoochorous seed dispersal by donkeys and goats was analysed, and the impact of grazing animals on dung beetle assemblages was studied in three highly frequented vegetation units, taking into account the intensity of use by the grazing animals. The results derived from this work highlight the importance of studying grazing animals and their interrelations within an island ecosystem. Moreover, the insights given in this thesis concerning the interrelations of grazing animals with different components of the island should open up the view on grazers and their multifaceted effects on the biodiversity, thus leading to management implementations for a sound functioning of the island ecosystem as well as the conservation and maintenance of biodiversity.
