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Distributive aspects in the design of payments for ecosystem services and agri-environmental schemes
(2021)
Payments for ecosystem services (PES) and agri-environmental schemes (AES) are often introduced with the goal to counteract overexploitation of natural habitats and biodiversity loss in forests and agricultural landscapes. Their ecological effectiveness and cost-effectiveness have been, however, repeatedly questioned in the literature.
One way of increasing the cost-effectiveness of such schemes is spatial differentiation of payments, which reflects regional differences in conservation benefits and costs and thus maximizes the ecological effect achieved with available financial resources.
Another major critique for PES and AES is that they often pursue poverty alleviation and rural development objectives, which can compromise their cost-effectiveness. As the Tinbergen rule in economic theory suggests, each policy goal requires a separate policy instrument.
However, as other policy instruments, PES and AES have distributional effects. Especially in developing countries, where governments are often weak and less able to successfully implement multiple policies, the distributional effects might not be adequately addressed. The distributional implications of PES and AES could even have an adverse effect on the cost-effectiveness of the schemes, if due to low acceptance among the potential ecosystem service (ES) providers, participation rates in these voluntary schemes are lower than optimal or if transaction costs are affected. From an economic perspective, if distributional goals are important for the design of PES and AES, the fairness preferences of potential ES buyers should be considered.
This thesis uses three case studies to address selected aspects of distribution and fairness in PES and AES from different perspectives. It provides insights into the preferences of potential ES buyers in Germany for distribution and other fairness aspects in PES and AES using two choice experiments and analyses possible distributional effects of cost-effective homogeneous and regionalized payments in AES.
The surveys among potential ES buyers suggest preferences for maximin and equal distribution of payments, and preferences for animal welfare and biodiversity conservation (for local as well as for distant biodiversity), which could be directions for improvement of AES and PES.
Regarding distributional impacts of AES, a trade-off between equality and cost-effectiveness is confirmed. Equity generally increases with improved cost-effectiveness of homogeneous payments. Spatially differentiated payments improve the cost-effectiveness substantially, by aligning the payments to the regional costs and the measures to the regional specifics and potential ecological benefits. However, they have substantial redistribution effects, poorer regions are adversely affected. This shows the importance of analyzing the distributional implications of cost-effective AES and PES on different spatial levels and calls for a holistic approach in policy evaluation and implementation.
Influence of Ectomycorrhiza on exudation of Low Molecular Weight carboxylates in Pinus sylvestris L.
(2008)
Ectomycorrhiza has a strong influence on exudation of both Low Molecular Weight (LMW) carboxylates and on the release of inorganic compounds into the rhizosphere. This process of exudation influences the chemical composition of the rhizosphere soil than the bulk soil. This specific chemical environment which is created in the rhizosphere significantly influences mineralization processes in the soil. Exudation is normally related to activities such as growth and physiological development of plant roots. Root secretions are also comprised of large range of organic and inorganic substances. To a large extent nutrient uptake by plants depends on the release of exudates in the form of LMW carboxylates, which in turn mobilize the required elements suitable for metabolic purposes by forming organometallic complexes. Root exudates influence the rhizosphere soil making it conducive for root proliferation. Exudates are well known for stimulating the metabolic activity of microbial communities in the rhizosphere. Correspondingly, microbes may enhance rhizodeposition by roots. The main objective of this research focuses on characterization of Low Molecular Weight (LMW) carboxylates in rhizosphere soil solution and their role in plant nutrition. For a better understanding of the characteristics of the root exudates, Pinus sylvestris L. tree seedlings, distinguished into non-mycorrhized as well as mycorrhized variants and were grown in petridish rhizotron. To reduce the influences of the unknown processes occurring in the natural environment, working under sterile conditions to much extent was preferred. To achieve maximum recovery of LMW carboxylates, density of the roots per volume in our petridish experiments was increased. Rhizosphere soil solutions were collected with the help of sterile plastic mini suction tubes (Rhizon). The types of exudates analyzed in the rhizosphere soil samples were oxalate/oxalic acid, L-malate/L-malic acid, citrate/citric acid, succinate/succinic acid and lactic acid. For identifying possible organometallic complexes, detection of labile ion concentration of the above LMW carboxylates was done using capillary electrophoresis and high performance liquid chromatography instruments. Growth of individual plants, within the treatment and across the variants was supposed to offer more information with regard to the influence of the ectomycorrhizal symbiosis on LMW carboxylate release. For inducing mycorrhization of the tree seedlings, a single strain of ectomycorrhiza (AM747290) was used to avoid influence of allelopathic interactions when more strains are used (Wöllecke 2001). In order to characterize the impacts of mycorrhization on characterization of LMW carboxylates, the plant morphological parameters, such as, root tissue density (RTD) and specific root length (SRL), along with the above and below ground biomass were measured for mycorrhizal and non-mycorrhized seedlings. The task of accurate measurements included the consideration of excess weight contributed by the quartz sand particles adhered to roots. Weight corrections were applied during chemical and morphological measurements to increase the accuracy. Further, the organometallic complexes in the rhizosphere solution were calculated using a geochemical modelling software tool - PHREEQC. Depending on the complex forming abilities of LMW carboxylates present in the rhizosphere, organometallic complexes are formed with the cations. The outcome of this task was a development of a conceptual model to predict and compare the nutrients present in the plant to their availability in the rhizosphere which was supplemented by artificial nutrient supply.