Influence of micro-site conditions and environmental gradients on tree-ring based climate reconstructions

Tree-ring chronologies are a powerful natural archive to reconstruct summer temperature variations of the late Holocene with an annual resolution. To develop these long-term proxy records tree-ring series are commonly extended back in time by combining samples from living trees with relict dead material preserved onshore or in lakes. Former studies showed that low frequency variations in such reconstructions can be biased if the relict and recent material is from different origins. A detailed analysis of the influence of various ecological (micro-) habitats representing the recent part is required to estimate potential errors in temperature estimates. The application of collective detrending methods, that comprise absolute growth rates, can produce errors in climate reconstructions and results in an underestimation of past temperatures. The appearance of these kind of micro-site effects is a wide-spread phenomenon that takes place all over Fennoscandia. Future research in this key region for dendroclimatology should take this issue into account. Especially the higher climate response at the lakeshore site is interesting to achieve smaller uncertainties when a tree-ring series is transformed to temperature anomalies. For new composite chronologies the main aim should be to minimize potential biases and this includes also micro-site effects.

The ecological and socio-economic role of Prosopis juliflora in Eritrea

In Eritrea findet eine rasche Verbreitung von Prosopis (juliflora) statt, die sich negativ auf die Naturresourcen als auch die sozio-ökonomische Lage der ländlichen Bevölkerung auswirkt. Die Landbevölkerung Eritrea's ist davon überzeugt, dass die Pflanze vor allem die Ernährungssicherung beeinträchtigt und will deshalb, dass sie ausgerottet wird. Die vorliegende Dissertation beschreibt die Auswirkung von Posopis auf lokale Öko- und Wirtschaftssysteme und zieht Vergleiche mit der diesbezüglichen Situation in anderen Ländern. Im Weiteren stellt sie einen Prosopis Management-Plan vor, dessen Ziel es ist, die zunehmende Verbreitung zu verhindern. Auch liefert sie eine Gegenüberstellung der Ansichten von wissenschaftlichen Experten einerseits und Bauern und Nomaden andrerseits. Sie zeigt auf, dass die weit verbreitete Annahme der Experten das Problem Prosopis durch ökonomische Nutzung ("eradication by utilisation") in Schach halten zu können, fraglich ist.

Evolution of South African Bruniaceae: evidence from ecological and geographical investigations

The central aim of the present study was to analyse ecological and geographical mechanisms that led to the species diversity and distribution pattern of the South African (sub-) endemic Bruniaceae shown today. To answer the question if the endangerment of some species and the sometimes restricted distribution area is due to an incongruence of pollination and breeding system, pollinator observations and the breeding system were analysed. rnThe effectiveness of the plant-pollinator interactions should be reflected in the reproductive success wherefore fruit set analyses were carried out. The genetic constitution of distant and close-by populations along a spatial gradient should illuminate gene-flow or habitat isolation that could have led to the species diversity. Since niche-inhabitation could be shown in the present study, an overall biogeographical analysis illuminated the distribution pattern on family level and the geographical as well as ecological factors that led to species persistence. rnThe study illuminated that the plant-pollinator interactions and the breeding system are adaptations to the fynbos biome but can not be defined as factors that drove speciation or have tremendous influence on distribution of Bruniaceae. In fact the geography of South Africa with its fragmented landscape as well as close niche-inhabitation of co-occuring species is the reason for species diversity and the recent distribution.rn

High-resolution reconstruction of Holocene climate variability and environmental changes in the North Pacific using bivalve shells

Bivalve mollusk shells are useful tools for multi-species and multi-proxy paleoenvironmental reconstructions with a high temporal and spatial resolution. Past environmental conditions can be reconstructed from shell growth and stable oxygen and carbon isotope ratios, which present an archive for temperature, freshwater fluxes and primary productivity. The purpose of this thesis is the reconstruction of Holocene climate and environmental variations in the North Pacific with a high spatial and temporal resolution using marine bivalve shells. This thesis focuses on several different Holocene time periods and multiple regions in the North Pacific, including: Japan, Alaska (AK), British Columbia (BC) and Washington State, which are affected by the monsoon, Pacific Decadal Oscillation (PDO) and El Niño/Southern Oscillation (ENSO). Such high-resolution proxy data from the marine realm of mid- and high-latitudes are still rare. Therefore, this study contributes to the optimization and verification of climate models. However, before using bivalves for environmental reconstructions and seasonality studies, life history traits must be well studied to temporally align and interpret the geochemical record. These calibration studies are essential to ascertain the usefulness of selected bivalve species as paleoclimate proxy archives. This work focuses on two bivalve species, the short-lived Saxidomus gigantea and the long-lived Panopea abrupta. Sclerochronology and oxygen isotope ratios of different shell layers of P. abrupta were studied in order to test the reliability of this species as a climate archive. The annual increments are clearly discernable in umbonal shell portions and the increments widths should be measured in these shell portions. A reliable reconstruction of paleotemperatures may only be achieved by exclusively sampling the outer shell layer of multiple contemporaneous specimens. Life history traits (e.g., timing of growth line formation, duration of the growing season and growth rates) and stable isotope ratios of recent S. gigantea from AK and BC were analyzed in detail. Furthermore, a growth-temperature model based on S. gigantea shells from Alaska was established, which provides a better understanding of the hydrological changes related to the Alaska Coastal Current (ACC). This approach allows the independent measurement of water temperature and salinity from variations in the width of lunar daily growth increments of S. gigantea. Temperature explains 70% of the variability in shell growth. The model was calibrated and tested with modern shells and then applied to archaeological specimens. The time period between 988 and 1447 cal yrs BP was characterized by colder (~1-2°C) and much drier (2-5 PSU) summers, and a likely much slower flowing ACC than at present. In contrast, the summers during the time interval of 599-1014 cal yrs BP were colder (up to 3°C) and fresher (1-2 PSU) than today. The Aleutian Low may have been stronger and the ACC was probably flowing faster during this time.

Sustainable development in Darjeeling Hills, India : ecological and socio-economic aspects for small-scale farmers with supportive observations from Kanagawa, Japan

Organic farming means a holistic application of agricultural land-use, hence, this study aimed to assess ecological and socio-economic aspects that show benefits of the strategy and achievements of organic farming in comparison to conventional farming in Darjeeling District, State of West Bengal, India and Kanagawa Prefecture/Kanto in Central Japan. The objective of this study has been empirically analysed on aspects of crop diversity, yield, income and sales prices in the two study regions, where 50 households each, i.e. in total 100 households were interviewed at farm-level. Therefore, the small sample size does not necessarily reflect the broad-scale of the use and benefit of organic farming in both regions. The problems faced in mountainous regions in terms of agriculture and livelihoods for small-scale farmers, which are most affected and dependant on their immediate environment, such as low yields, income and illegal felling leading to soil erosion and landslides, are analyzed. Furthermore, factors such as climate, soils, vegetation and relief equally play an important role for these farmers, in terms of land-use. To supplement and improve the income of farmers, local NGOs have introduced organic farming and high value organic cash crops such as ginger, tea, orange and cardamom and small income generating means (floriculture, apiary etc.). For non-certified and certified organic products the volume is given for India, while for Japan only certified organic production figures are given, as there are several definitions for organic in Japan. Hence, prior to the implementation of organic laws and standards, even reduced chemical input was sold as non-certified organic. Furthermore, the distribution and certification system of both countries are explained in detail, including interviews with distribution companies and cooperatives. Supportive observations from Kanagawa Prefecture and the Kanto region are helpful and practical suggestions for organic farmers in Darjeeling District. Most of these are simple and applicable soil management measures, natural insect repelling applications and describe the direct marketing system practiced in Japan. The former two include compost, intercropping, Effective Microorganisms (EM), clover, rice husk charcoal and wood vinegar. More supportive observations have been made at organic and biodynamic tea estates in Darjeeling District, which use citronella, neem, marigold, leguminous and soil binding plants for soil management and natural insect control. Due to the close ties between farmers and consumers in Japan, certification is often neither necessary nor wanted by the producers. They have built a confidence relationship with their customers; thus, such measures are simply not required. Another option is group certification, instead of the expensive individual certification. The former aims at lower costs for farmers who have formed a cooperative or a farmers' group. Consumer awareness for organic goods is another crucial aspect to help improve the situation of organic farmers. Awareness is slightly more advanced in Kanto than in Darjeeling District, as it is improved due to the close (sales) ties between farmers and consumers in Kanto. Interviews conducted with several such cooperatives and companies underline the positive system of TEIKEI. The introduction of organic farming in the study regions has shown positive effects for those involved, even though it still in its beginning stages in Darjeeling District. This study was only partly able to assess the benefits of organic agriculture at its present level for Darjeeling District, while more positively for the organic farmers of Kanto. The organic farming practice needs further improvement, encouragement and monitoring for the Darjeeling District farmers by locals, consumers, NGOs and politicians. The supportive observations from Kanagawa Prefecture and the Kanto region are a small step in this direction, showing how, simple soil improvements and thus, yield and income increases, as well as direct sales options can enhance the livelihood of organic farmers without destroying their environment and natural resources.

Method development using ICP-MS and LA-ICP-MS and their application in environmental and material science

Within this PhD thesis several methods were developed and validated which can find applicationare suitable for environmental sample and material science and should be applicable for monitoring of particular radionuclides and the analysis of the chemical composition of construction materials in the frame of ESS project. The study demonstrated that ICP-MS is a powerful analytical technique for ultrasensitive determination of 129I, 90Sr and lanthanides in both artificial and environmental samples such as water and soil. In particular ICP-MS with collision cell allows measuring extremely low isotope ratios of iodine. It was demonstrated that isotope ratios of 129I/127I as low as 10-7 can be measured with an accuracy and precision suitable for distinguishing sample origins. ICP-MS with collision cell, in particular in combination with cool plasma conditions, reduces the influence of isobaric interferences on m/z = 90 and is therefore well-suited for 90Sr analysis in water samples. However, the applied ICP-CC-QMS in this work is limited for the measurement of 90Sr due to the tailing of 88Sr+ and in particular Daly detector noise. Hyphenation of capillary electrophoresis with ICP-MS was shown to resolve atomic ions of all lanthanides and polyatomic interferences. The elimination of polyatomic and isobaric ICP-MS interferences was accomplished without compromising the sensitivity by the use of a high resolution mode as available on ICP-SFMS. Combination of laser ablation with ICP-MS allowed direct micro and local uranium isotope ratio measurements at the ultratrace concentrations on the surface of biological samples. In particular, the application of a cooled laser ablation chamber improves the precision and accuracy of uranium isotopic ratios measurements in comparison to the non-cooled laser ablation chamber by up to one order of magnitude. In order to reduce the quantification problem, a mono gas on-line solution-based calibration was built based on the insertion of a microflow nebulizer DS-5 directly into the laser ablation chamber. A micro local method to determine the lateral element distribution on NiCrAlY-based alloy and coating after oxidation in air was tested and validated. Calibration procedures involving external calibration, quantification by relative sensitivity coefficients (RSCs) and solution-based calibration were investigated. The analytical method was validated by comparison of the LA-ICP-MS results with data acquired by EDX.

Welche Typen von Autokratien sind leistungsfähiger und warum? : eine empirische Analyse auf Grundlage der Selektoratstheorie = Which type of autocracy performs better, and why?

Performanzunterschiede zwischen verschiedenen Autokratietypen wie Monarchien, Militär-, Ein-Parteien- und begrenzten Mehr-Parteien-Regimen sind bis auf wenige Ausnahmen bisher relativ unerforscht. Deshalb widmet sich diese Arbeit folgenden Forschungsfragen: Gibt es Performanzunterschiede zwischen verschiedenen Autokratietypen? Wenn ja, wie gestalten sich diese und wie lassen sie sich erklären? Auf Grundlage der Selektoratstheorie von Bueno de Mesquite et al. wird die Hypothese aufgestellt, dass die Performanz politischer Regime mit der Größe der Winning Coalition steigt. Da verschiedene Autokratietypen unterschiedlich große Winning Coalitions haben, wird angenommen, dass es deutliche Performanzunterschiede zwischen diesen Typen gibt. Als Performanzkriterien dienen in dieser Arbeit wirtschaftlicher Wohlstand, soziale Sicherheit und ökologische Nachhaltigkeit. Aus diesen drei Kriterien wird zusätzlich ein Indikator allgemeiner Performanz gebildet. Die empirische Untersuchung erfolgt mit den Daten des Quality-of-Governement-Datensatzes und erstreckt sich über 140 autokratische Länder im Zeitraum von 1972 bis 2010. Die Daten werden mittels Time-Series-Cross-Section-Regressionen analysiert. Die Ergebnisse der Analysen entsprechen nur teilweise den Erwartungen. Die Größe der Winning Coalition wirkt positiv auf die wirtschaftliche Wohlfahrt und die soziale Sicherheit und damit auch auf die allgemeine Performanz aus. Entgegen den Erwartungen sinkt die ökologische Performanz jedoch mit steigender Größe der Winning Coalition. Auch die Befunde bezüglich der Performanz verschiedener Autokratietypen entsprechen nicht den Erwartungen. So sind Ein-Parteien-Regime insgesamt leistungsfähiger als Mehr-Parteien-Regime, Militär-Regime und Monarchien. Militär-Regime sind leistungsfähiger als Monarchien und tendenziell auch als Mehr-Parteien-Regime.

Anthropology in the twenty-first century : a view of, and from, Germany

The article explores the developments in German-language anthropology in the past decades, focussing on the period after the 1970s. It argues that the recent history of German-language Ethnologie (social and cultural anthropology) is one of catching-up modernization. German-speaking anthropologists are increasingly involved in, and contribute to, broader theoretical debates, publish in English and in international journals, and are actively engaged in international academic networks. The paper discusses how and under what conditions of knowledge production these transformations have taken place. It analyses the changing institutional environment in which German anthropologists have worked and work today, as well as the theoretical impulses from within and outside the discipline that have given rise to the contemporary orientation of German-language anthropology as an anthropology of the 'present'. Finally, and beyond the focus on Germany, the article offers some ideas on the future of anthropology as a symmetrical social science, characterized by a continued strong reliance on field work and a high level of 'worldliness', a basic attitude of systematically shifting perspectives, the critical reflection of the social and political embeddedness of knowledge production, and an engagement with social theory across disciplinary boundaries.