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- Biodiversität (16) (entfernen)
Managing increasing environmental risks through agro-biodiversity and agri-environmental policies
(2008)
Agro-biodiversity can provide natural insurance to risk-averse farmers by reducing the variance of crop yield, and to society at large by reducing the uncertainty in the provision of public-good ecosystem services such as e.g. CO2 storage. We analyze the choice of agro-biodiversity by risk-averse farmers who have access to financial insurance, and study the implications for agri-environmental policy design when on-farm agro-biodiversity generates a positive risk externality. While increasing environmental risk leads private farmers to increase their level of on-farm agro-biodiversity, the level of agro-biodiversity in the laissez-faire equilibrium remains inefficiently low. We show how either one of two agri-environmental policy instruments can cure this risk-related market failure: an ex-ante Pigouvian subsidy on on-farm agro-biodiversity and an ex-post compensation payment for the actual provision of public environmental benefits. In the absence of regulation, welfare may increase rather than decrease with increasing environmental risk, if the agroecosystems is characterized by a high natural insurance function, low costs and large external benefits of agro-biodiversity.
Agro-biodiversity can provide natural insurance to risk averse farmers. We employ a conceptual ecological-economic model to analyze the choice of agrobiodiversity by risk averse farmers who have access to financial insurance. We study the implications for individually and socially optimal agro-ecosystem management and policy design when on-farm agro-biodiversity, through ecosystem processes at higher hierarchical levels, generates a positive externality on other farmers. We show that for the individual farmer natural insurance from agro-biodiversty and financial insurance are substitutes. While an improved access to financial insurance leads to lower agro-biodiversity, the e_ects on the market failure problem (due to the external benefits of on-farm agro-biodiversity) and on welfare are determined by properties of the agro-ecosystem and agro-biodiversity’s external benefits. We derive a specific condition on agro-ecosystem functioning under which, if financial insurance becomes more accessible, welfare in the absence of regulation increases or decreases.
Agrobiodiversität besitzt vielfältigen ökologischen, ökonomischen und sozio-kulturellen Wert. Sie ist eine grundlegende Voraussetzung für zukünftige Nutzungen und steht gleichzeitig in einem besonderen Verhältnis zu menschlichem Handeln. Zwar basiert Agrobiodiversität auf Natur, sie ist jedoch wesentlich durch landwirtschaftliche Tätigkeiten gestaltet worden und kann ohne weitere Nutzung durch den Menschen nicht erhalten und erneuert werden. Die vorliegende Dissertation analysiert die Gestaltung gesellschaftlicher Naturverhältnisse in der ländlichen Entwicklung am Beispiel der nachhaltigen Nutzung von Agrobiodiversität. Schutz und Nutzung von Agrobiodiversität wird hierfür in einem ersten Schritt als sozial-ökologisches Phänomen konzipiert. Daran schließen sich Analysen auf agrarpolitischer und landwirtschaftlich praktischer Ebene an. Anhand einer Analyse der der Gemeinsamen Agrarpolitik der Europäischen Union (GAP) und im speziellen der Politik zur ländlichen Entwicklung wird deutlich, dass eine programmatische Orientierung an Wettbewerbsfähigkeit und einer nachhaltigen Entwicklung besteht und das Paradigma einer multifunktionalen Landwirtschaft integrierende Ansätze bietet. Diese Ansätze werden jedoch weiterhin vor dem Hintergrund einer unhinterfragten Logik realisiert, die davon ausgeht, dass naturerhaltendes Wirtschaften nicht wettbewerbsfähig sein kann. Die GAP löst somit die hierarchische Trennung zwischen Schutz und Nutzung von Agrobiodiversität nicht auf. Trotz der Wirkmächtigkeit der GAP kann mittels der Fallstudie "Arche-Region Flusslandschaft Elbe" an einem konkreten Beispiel aus der landwirtschaftlichen Praxis dargestellt werden, wie nachhaltige Agrobiodiversitätsnutzung umgesetzt wird. Aus den Ergebnissen der Fallstudie werden abschließend Schlussfolgerungen für eine Weiterentwicklung der Politik zur ländlichen Entwicklung und EU-Agrarpolitik im Allgemeinen abgeleitet.
Neben dem Klimawandel und der Verstädterung zählt der Verlust biologischer und kultureller Vielfalt mit unberechenbaren Konsequenzen für die Bereitstellung von Ökosystemdienstleistungen zu den größten Herausforderungen der Zukunft, auch in UNESCO-Biosphärenreservaten, die Modellregionen für nachhaltige Entwicklung sind. Deshalb wurden durch die vorliegende Studie erstmalig Ökosystemdienstleistungen im UNESCO-Biosphärenreservat Schaalsee erfasst und bewertet. Dort sind insgesamt 39 Ökosystemdienstleistungen nachzuweisen, wobei räumliche Unterschiede hinsichtlich der Zonierung zu beobachten sind: Je strenger der Schutzstatus, desto geringer ist die Anzahl an nutzbaren Ökosystemdienstleistungen. Mittels Q-Methode wurden fünf unterschiedliche Werteperspektiven auf die bereitgestellten Ökosystemdienstleistungen identifiziert: 1) Übereinstimmung mit der Biosphärenreservats-Idee, 2) Regionalität mit dem Streitpunkt Kultur, die als a) entbehrlicher Luxus oder b) elementarer Lebensinhalt wahrgenommen wird, 3) Landwirtschaft und Nostalgie sowie 4) Vorsorge durch natürliche Regulierungsleistungen. Alle Perspektiven stimmen darin überein, dass die Vielfalt der Natur und sauberes Trinkwasser sowie die meisten regulierenden Ökosystemdienstleistungen von großer Wichtigkeit sind. Die Ergebnisse der Erfassung können als Grundlage zur weiteren Untersuchung der Ökosystemdienstleistungen im UNESCO Biosphärenreservat Schaalsee verwendet werden.
The European Union’s Council Regulation on support for rural development by the European Agricultural Fund for Rural Development has introduced auctioning as a new instrument for granting agri-environmental payments and awarding conservation contracts for the recent multi-annual budgetary plan. This paper therefore deals with the conception and results of two case study auctions for conservation contracts. Results of two field experiments show much differentiated bid prices in the model-region and budgetary cost-effectiveness gains of up to 21% in the first auction and up to 36% in the repeated auction. Besides these promising results, some critical aspects as well as lessons to be learned will also be discussed in this paper to improve the design and performance of upcoming conservation auctions.
Ensuring food security and halting biodiversity loss are two of the most pressing global sustainability challenges. Attempts to identify pathways have been dominated with a biophysical-technical focus that provides technical solutions to the integration of food security and biodiversity conservation. The social-political dimension, however, including equity, governance, and empowerment received little to no attention. By focusing on the poorly investigated social-political dimension, this dissertation aimed to identify governance properties that facilitate and impede the integration of food security and biodiversity conservation through an empirical case study conducted in a multi-level governance setting of southwestern Ethiopia. To address the overarching goal of this dissertation, first the author examined how the existing widely discussed food security approaches and agricultural land use framework, land sparing versus land sharing unfold in the local context of southwestern Ethiopia. The finding in this dissertation indicated that the existing global framing of food security approaches as well as frameworks around agricultural land use has limited applicability in on-the-ground realities mainly because landscapes are complex systems that consist of stakeholders with multiple and (often) conflicting interests. This was evident from the finding that local land use preference was not a matter of "either/or", but instead involved mixed features exhibiting properties of both land sparing and land sharing. Moreover, in addition to the biophysical factors embedded in the existing food security approaches and land use frameworks, stakeholders preference involved social factors such as the compatibility of land use strategy with local values and traditions, which are mainly unaccounted in the existing global frameworks. Findings in this dissertation revealed that the existing reductionist analytical framings to the issues of food security and biodiversity conservation seldom address the complexity inherent within and between food security and biodiversity conservation sectors. Second, this dissertation identified governance structural and process related challenges that influence individual as well as integrated achievements of food security and biodiversity conservation goals. The result of the study showed that the governance of food security and biodiversity conservation was characterized by a strongly hierarchical system with mainly linear vertical linkages, lacking horizontal linkages between stakeholders that would transcend administrative boundaries. Furthermore, with regard to the governance process, three key and interdependent categories of governance process challenges namely, institutional misfit, the problem of interplay, and policy incoherence influenced the achievement of individual and integrated goals of food security and were identified. Given the interdependence of these governance challenges, coupled with the complexity inherent in the food security and biodiversity conservation, attempts to achieve the dual goals thus needs an integrative, flexible and adaptive governance system Third, to understand how food security and biodiversity conservation unfold in the future, the author explored future development trajectories for southwestern Ethiopia. Iterative scenario planning process produced four plausible future scenarios that distinctly differed with regard to dominating land use strategies and crops grown, actor constellations and governance mechanisms, and outcomes for food security and biodiversity conservation. Three out of the four scenarios focused on increasing economic gains through intensive and commercial agricultural production. In contrast, one scenario involved features that are widely considered as beneficial to food security and biodiversity conservation, such as agroecological production, diversification practices, and increased social-ecological resilience. In smallholder landscapes such as the one studied here, such a pathway that promises benefits for both food security and biodiversity conservation may need to be given greater emphasis. In order to ensure the integration of food security and biodiversity conservation, recognizing their interdependence and addressing the challenges in a way that fits with the local dynamics is essential. In addition, addressing the food security-biodiversity nexus requires a holistic analytical lens. Moreover, this dissertation indicated that there is a clear need to pay attention to the governance structure that accommodates the diversity of perspectives, enable participation and strong coordination across geographical boundaries, policy domains and governance levels. Finally, this dissertation revealed opportunities to integrate food security and biodiversity through the pro-active management of social-ecological interactions that produce a win-win outcome. The win-win outcome could be achieved in a system that involve properties such as diversification and modern agroecological techniques, smallholders empowerment, emphasize adaptive governance of social-ecological systems, value local knowledge, culture and traditions, and ensure smallholders participation.
The role of tree diversity for individual tree growth, crown architecture and branch demography
(2012)
In the light of the concurrent loss of biodiversity, biodiversity and ecosystem functioning (BEF) research attracted a great deal of attention and emerged as one of the important fields of research in ecology. Since important ecological interactions such as competition occur between individuals, the understanding of individual tree growth was considered to be fundamental for forest related BEF research. Individual tree growth is determined by the above- and belowground interactions of a tree individual with its local neighbourhood. To obtain a deeper understanding of BEF relationships, I broadened the focus from individual tree growth (usually measured as diameter or biomass increment) to the arrangement and dynamics of the above-ground modules of trees in dependence of their local neighbourhood. More precisely, the main objective of the present thesis was to analyse the impact of tree diversity on individual tree growth, crown architectural and branch demographic variables. Thereby I considered crown architectural variables as important indicators of the competition for light. In addition, crown architectural variables impacted ecosystem services such as erosion control. Furthermore, the results of the present thesis contributed to the current discussion on species coexistence theories, which may be differentiated by two opposing views: one that relies on neutral processes and one that implicates a role for meaningful differences in the ecological strategy (niche) of co-occurring species. The studied forest ecosystems were the subtropical broad-leaved evergreen forests of southeast China, which have been under high human pressure due to a long history of intensive land-use. The area is of particular interest for BEF research due to the high species richness of woody plants, including many, yet poorly studied species, and due to the rough terrain with steep slopes, which cause severe soil erosion. The present thesis combines three observational with two experimental studies, applying the local neighbourhood approach along an age gradient from tree saplings to mature trees. In the Gutianshan National Nature Reserve (GNNR), I conducted two observational studies on permanent plots which were chosen according to a space-for-time substitution design. The aim of the first study was to reveal the effects of diversity (species richness, functional diversity) together with other biotic and abiotic variables on morphological growth parameters (crown area, crown displacement and stem inclination) of target trees of four tree species (Castanea henryi, Castanopsis eyrei, Quercus serrata and Schima superba). In the second study, the same target trees together with their neighbours were used to analyse the relation between stand related functional diversity and the horizontal and vertical structure of the canopy. The third study was conducted in a young secondary broad-leaved evergreen forest. Using two target species (Castanopsis fargesii and Quercus fabri), the role of diversity, intra- vs. inter-specific competition and the mode of competition (symmetric vs. asymmetric) on the target individuals was tested by analysing five-year radial growth increments. The two other studies were carried out in an experimentally established plantation, using saplings of four tree species (C. henryi, Elaeocarpus decipiens, Q. serrata and S. superba), which were planted in monoculture, twoand four-species combinations and in three densities. The fourth study focused on mechanisms of coexistence and the role of species richness, species composition, species identity and density on sapling growth. The fifth study tested the effect of sapling density and identity on the througfall kinetic energy, which represents a measure for the erosive power of rain. It was found that functional diversity does affect crown architectural and canopy related parameters of forests in the GNNR. However, no effects of species richness on radial-growth were detected in the younger forest. Since I also did not find strong effects of species richness on saplings in the experimental plantation, diversity effects may evolve at a later age stage. The importance of the diversity effect may be related reversely to that of species identity in an age gradient of forest stands. The findings suggest that different mechanisms of coexistence operate simultaneously but that their relative importance may shift through the life stages of trees. During the sapling stage, species-specific differences in growth and architectural traits support niche theory. In older forest stands, no species-specific differences in growth parameters could be detected. However, I did find effects of functional diversity on horizontal canopy structure. I conclude that mechanisms of coexistence may not only change with forest stand age, but may also differ for distinct traits. The present thesis, being the first to apply the local neighbourhood approach with regard to crown architecture and branch demography within the BEF field of research, stresses the importance of this individual based approach. Although the observed forest systems are very complex, crown architectural and canopy structural variables were found to be affected by diversity. The finding that the degree of erosive power of rain could be elucidated by crown architectural variables, encourages further studies to reveal possible relations between biodiversity and other ecosystem functions or services, which might be mediated by crown architectural and canopy structural variables.