Geographische Beiträge zur abiotischen Ausstattung des Biosphärenreservats Rhön

Durch die Untersuchungen zur abiotischen Ausstattung im Biosphärenreservat Rhön wurden neue wissenschaftliche Kenntnisse und Erkenntnisse erarbeitet, die auch für die biotische Forschung sowie den Arten- und Biotopschutz von großer Bedeutung sind. Durch eine Integration abiotischer und biotischer Forschungsansätze, wie sie gerade für Biosphärenreservate typisch sein sollte (SCHAAF 1998), sind noch weit mehr neue, z.T. sogar spektakuläre Erkenntnisse, z.B. über Reliktarten und die Artenevolution, zu erwarten. Andererseits stellen die hier kurz vorgestellten Ergebnisse zur abiotischen Ausstattung im Biosphärenreservat wichtige Informationen für die Öffentlichkeitsarbeit des Biosphärenreservats und der gesamten Region dar. Eine anschauliche Präsentation von mehr abiotischen Besonderheiten vor Ort und in geeigneten Informationsmedien dürfte zur Erhöhung der Attraktivität und damit auch zu mehr Besuchern in der Region beitragen

Intertemporal Information Acquisition and Investment Dynamics

This paper studies intertemporal information acquisition by agents that are rational Bayesian learners and that dynamically optimize over consumption, investment in capital, and investment in information. The model predicts that investors acquire more information in times when future capital productivity is expected to be high, the cost of capital is low, new technologies are expected to have a persistent impact on productivity, and the scalability of investments is expected to be high. My results shed light on the economic mechanisms behind various dynamic aspects of information production by the financial sector, such as the sources of variation in returns on information acquisition for investment banks or private equity funds

Learning, Active Investors, and the Returns of Financially Distressed Firms

I develop an analytically tractable dynamic asset pricing model to study expected returns of financially distressed firms in the presence of learning about firm fundamentals and endogenous information acquisition by active investors. The model reveals that learning and information acquisition critically affect lowfrequency risk exposures close to default and can, counter to standard models, rationalize low and even negative expected return premia for firms with high default risk. Similar to Schumpeter’s (1934) argument that recessions have a positive, cleansing effect on the economy, the model reveals that equity holders naturally benefit from an increased speed of learning about truly insolvent firms in downturns, which positively affects the value of their default option in these times. Equity holders’ option value is similarly enhanced by the ability to partially freeride on active investors’ information acquisition. Learning thus dynamically affects distressed firms’ exposures to business-cycle frequency risks and can rationalize striking, momentum-type dynamics in risk premia

Rating Agencies in the Face of Regulation

This paper develops a theoretical framework to shed light on variation in credit rating standards over time and across asset classes. Ratings issued by credit rating agencies serve a dual role: they provide information to investors and are used to regulate institutional investors. We show that introducing rating-contingent regulation that favors highly rated securities may increase or decrease rating informativeness, but unambiguously increases the volume of highly rated securities. If the regulatory advantage of highly rated securities is sufficiently large, delegated information acquisition is unsustainable, since the rating agency prefers to facilitate regulatory arbitrage by inflating ratings. Our model relates rating informativeness to the quality distribution of issuers, the complexity of assets, and issuers\u27 outside options. We reconcile our results with the existing empirical literature and highlight new, testable implications, such as repercussions of the Dodd-Frank Act

The Effects of Anthropogenic Impact on Plant and Soil Cover in Mongolia

Under the prevailing variable natural conditions nomadic pastoralism was the most suitable form of land use in Mongolia and the neighboring countries in the past. Furthermore, small areas were used for agriculture in some regions. Therefore, anthropogenic influence was present throughout history. In the forest steppe zone this led to the disappearance of forest sites which then gave way to meadow steppe. The severe impact on the natural pastures by continuous increase of livestock herding and other human activities was perceptible during the socialist period. But since the 1990s, after the transition to market economy, this impact has increased greatly and a great number of degradation features and irreversible damages in the plant and soil cover can be observed now. Especially in the vicinity of the Mongolian capital Ulaanbaatar, along the north-south road corridor from Russia to the Chinese border, but also in some western regions of the country herders concentrate their livestock in search for better marketing opportunities. Especially there, the vegetation in vast areas is overgrazed by biting and trampling to such an extent that its regeneration is endangered. Degraded and devastated pasture types with a decrease of valuable forage plants and a high increase of ruderal elements can be found in these grasslands. Characteristic sequences of pasture degradation are presented here. The degradation effects steppes and desert steppes as well as reed, mire, and meadow vegetation in the river valleys and lowlands. In the desert regions saxaul vegetation is especially threatened. In some cases after degradation of the plant cover these degradation processes effect soil cover, too. Impacts on soil cover caused by ploughing of virgin land, by ploughing of long term used arable land, and by irrigation are the main reasons for soil degradation. Also recreational activities in the vicinity of settlement centers and traffic along the tracks lead to detrimental vegetation and soil cover changes. Unsystematic forest clearing goes on at a high level and often results in irreversible soil degradation

Asymmetric Information and Intermediation Chains

We propose a parsimonious model of bilateral trade under asymmetric information to shed light on the prevalence of intermediation chains that stand between buyers and sellers in many decentralized markets. Our model features a classic problem in economics where an agent uses his market power to inefficiently screen a privately informed counterparty. Paradoxically, involving moderately informed intermediaries also endowed with market power can improve trade efficiency. Long intermediation chains in which each trader\u27s information set is similar to those of his direct counterparties limit traders\u27 incentives to post prices that reduce trade volume and jeopardize gains to trade

Dust storms, dust transfer and depositions in the southern Aral Sea region

Land surfaces poor in vegetation coverage and dried out soils are accelerating factors of sand and dust transport. Dust transport also has considerable impact on the human society if highly populated regions are on the transport pathway or sink areas as dust transport can bring pollutants into residence areas. The quantitative prediction of dust storms is impossible unless the entire dust cycle, consisting of dust emission, transport and deposition, can be correctly assessed. In recent years, dust emission schemes have been developed that account reasonably well for the impacts of atmospheric forcing and land-surface properties on dust emission. The Aral Sea disaster has been caused by the overexploitation of the water and land resources and is related to problems of polluted surface and ground water bodies, the loss of agricultural productivity and biodiversity, the regional climate change and also the human health, especially within the disaster zone. Major consequences of the Aral Sea shrinkage, apart from the decrease of its water volume and area, an increase of the water salinity and a modification of the salinity pattern is the formation of a vast saline desert with the area of almost 3.6 mln ha on the exposed seabed. The main factors of dust storm occurrences are the frequency of strong winds and availability of source material in dust emission sites. During the last decades the total area of dust emission sites in the Aral Sea region increased significantly because of the shrinking of the Aral Sea and consequent drying of its exposed bottom and deltaic areas of Amudarya and Syrdarya Rivers

Ecological, socio-economic and demographic analyses as prerequisites for sewage treatment problem solutions in rural areas. The case study of Dirlammen, Vogelsberg, Germany

The municipal sewage treatment in Germany is traditionally centralized and allows for a high disposal security. The implementation of the EU Water Framework Directive (EU-WFD) showed that the central target, the so-called ‘good ecological state’ has not yet been reached in 90% of all surface water bodies. A common and widespread measure to reach said target is the improvement of sewage treatment plants (STP). A large part of the expenses for that has to be shouldered by local communities. But many rural communities already have to manage high costs caused by the modernization of the sewage pipe system. And as the size of the rural population decreases continuously, the per capita burden increases. This raises the question whether the construction of a new sewage treatment plant is the most efficient way to improve the water quality in rural areas. A comprehensive approach has been developed for answering this question, consisting of 1) biological and physico-chemical wastewater analyses, 2) a modified eco-balance for the construction of a new STP and 3) socio-economic and demographic population analyses. The results show that the water quality of the studied creek is good with exception of the sewage disposal point. The eco-balance for the construction, the operation, and the environmental side effects show that the continued operation of the existing STP is more effective than the construction of a modern facility. This conclusion is supported by the aging and general decrease of the rural population. The diminishing potential to shoulder additional costs is in contrast to the reduced future demand for a modern STP