Abschlussarbeiten - Exp. Pflanzenökologie
Im Folgenden findest Du die Themenvorschläge für Bachelor- (BA) oder Masterarbeiten (MA), welche ab sofort bearbeitet werden können. Die Themen sind chronologisch nach ihrem potentiellen Startpunkt geordnet.
Bei Interesse an einem der vorgeschlagenen Themen, wende dich bitte an die verantwortliche Person. Bei Fragen zu mehreren Themen oder eigenen Ideen kontaktiere bitte Prof. Jürgen Kreyling.
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Die AG „Experimentelle Pflanzenökologie“ schreibt für 2019 folgende Themen für B.Sc.- und M.Sc.-Arbeiten aus:
1. Assessing root decomposition in drained and re-wetted peatlands (BA or MA)
- Thema vergeben -
Peatlands are globally important carbon stores, but drainage of peatlands has led to large emission of greenhouse gases as decomposition is accelerated. To reduce greenhouse gas emissions, peatlands are re-wetted in the hope of restoring low decomposition rates and their potential as carbon stores. Here, the decomposition rates in three different types of drained and re-wetted peatlands (alder carr, percolation mire and coastal mire) are assessed. This project is within the framework of WETSCAPES.
2. Assessing root production in drained and re-wetted peatlands (BA or MA)
- Thema vergeben -
Peatlands are globally important carbon stores, but drainage of peatlands has led to large emission of greenhouse gases as decomposition is accelerated. To reduce greenhouse gas emissions, peatlands are re-wetted in the hope of restoring low decomposition rates and their potential as carbon stores. Here, the annual root production in three different types of drained and re-wetted peatlands (alder carr, percolation mire and coastal mire) are assessed. This project is within the framework of WETSCAPES.
3. Photosynthetic activity of plants during winter in relation to temperature and intensity of temperature fluctuations (BA or MA)
Date sampling: Late autumn 2018 and winter 2019
Contact: Ilka Beil, Jürgen Kreyling
Winters are predicted to become milder but more unsteady in future. Many herbal plants stay active as long as there is no frost and snow. Here we want to quantify the photosynthetic activity in relation to ambient temperature as well as to what extend this is influenced by strong temperature fluctuations.
Methods: Photosynthetic activity (CO2 flux) of rapeseed (Brassica napus) under a constant light source will be measured at different temperatures. For simulation of temperature fluctuations, we will use greenhouses or climate chambers.
4. Influence of temperature and photoperiod on bud dormancy and phenology in trees (BA or MA)
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5. Phenology of geophytes in deciduous forests (BA)
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Understory geophytes in deciduous forests complete their reproduction very early in the year before the tree canopy closes. Therefore, they are indicators of climate change in late winter. Here, differences in geophyte phenology between climatically different locations are to be studied.
6. Influence of drought on spring phenology of European Beech (BA)
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7. Frost resistance of early vs. late flushing species (MA)
- Thema vergeben -
We observed spring phenology of about 500 woody species in the Arboretum for 3 years now. The leave unfolding dates differ by about 100 days between the earliest and the latest species. Aiming to understand the phenological strategies of the species from the ecological and evolutionary point of view, spring phenology can be understood as a trade-off between the advantage of an early growing season on one hand and the risk of frost damage to the fresh leaves on the other.
8. Age and turnover of tree roots in a drained and re-wetted alder swamp (1 MA or 2 BA)
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Dendrochronology is a common tool to determine the age of trees. Less attention is hereby put on the belowground part of the plant, because it is often overlooked that also roots, not only stems, form the so-called growth rings. The longevity of roots determines the turnover rates (how much biomass enters and exits the system) which, on the other hand, defines how much organic matter is available for decomposers in these systems. Alder swamps are forested wetlands and therefore function as important carbon stores. Peat, the most important carbon store, can only be formed when production of plant biomass exceeds its decomposition. In this context, the age distribution of roots of Alnus glutinosa in different depth levels shall be investigated and either compared between trees growing in a rewetted and a drained Alder swamp as a master thesis or investigated separately in two bachelor thesis.
9. Putting the root growth of an extreme year into perspective (MA or 2 BA)
Date sampling: Growing season (March to October 2019 with individual timing to be discussed)
Location: Peatlands in MV.
Contact: Juergen Kreyling, Sarah Schwieger
Peatlands are globally important carbon stores, but drainage of peatlands has led to large emission of greenhouse gases as decomposition is accelerated. To reduce greenhouse gas emissions, peatlands are re-wetted in the hope of restoring low decomposition rates and their potential as carbon stores. Here, the root growth dynamics in three different types of drained and re-wetted peatlands (alder carr, percolation mire and coastal mire) are assessed by the minirhozotron technique. The same observations occurred already in the extremely dry and warm year 2018, when water tables even in the rewetted fens dropped below -60 cm. Here, we now aim at putting this extreme year into perspective to another, more normal year. This project is within the framework of WETSCAPES.
Methods: Using minirhizotrons (root cameras), root growth in space and time is analysed at drained and re-wetted peatlands in MV, which will be visited regularly during the growing season. A driving license is needed and an own car is a merit (travel costs will be covered).
10. Lag-effects of different winter soil temperature regimes on fine root growth and decomposition rates in beech forests varying in winter harshness (BA or MA)
Data sampling: April 2019 (10 days fieldtrip)
Location: Experimental sites in Germany and Poland.
Contact: Juergen Kreyling Robert Weigel
Effects of global warming will be most pronounced in winter. A reduction in insulating snow cover due to warmer atmospheric temperature, however, could induce soil cooling during winter. This may affect plant roots leading to shifts in root phenology and rooting depth. Furthermore, decomposition rates of organic material may decrease due to a disturbed decomposer community. To alter soil temperatures, we manipulated snow cover (Figure 1 left) in winter 2016/2017 at 9 beech forest sites along a winter temperature gradient between Rostock and Dansk (Figure 1 right). Previous work in the project indicated that there may be long-lasting effects of the one-time soil temperature manipulation for root growth and decomposition in particular. Therefore, this thesis tests for lag-effects of different soil temperature regimes on root growth by non-intrusive root photography (minirhizotron technique) and on decomposition rates by a tea-bag-decomposition experiment. The candidate will accompany us to all sites to take root pictures and excavate tea bags. Presumably, six one-day field trips will start in Greifswald. One field trip will include 3 experimental sites in Poland, with overnight stay close to Dansk. Travel costs are paid for. The thesis builds up on knowledge from a previous Bachelor thesis.
Methods: Minirhozotrone root imaging during the field trips in Germany and Poland; quantification of fine root length with software rootfly or comparable software (e.g., root snap, QGIS); excavation of decomposition bags (tea bags) and measuring loss in dry weight (lab work back in Greifswald), data analysis with R (preferably)
11. Root phenology of wetland plants in response to water regime (1 MA or 2 BA)
Data sampling: regularly during the field season of 2019 (April to September), with individual timing to be discussed
Location: mesocosms in the common garden in Greifswald
Contact: Juergen Kreyling, Gesche Blume-Werry
Plant roots have key roles in ecosystem function and are of special importance in fens, where roots and rhizomes form peat and thus are the main contributors to large carbon stores. However, little is known about the root dynamics of different species, how they respond to changes in water table height, and how species respond to competition. This project is within the framework of WETSCAPES.
Methods: Using minirhizotrons (root cameras) in a mesocosm facility to assess root growth and root architecture in fen species originating under different water table regimes.
12. Determining optimal conditions for paludiculture in Typha and Phragmites (several BA or MA)
Data sampling: May-October 2019 (several topics possible with different timings)
Location: Mesocosm experiment Greifswald and/or field experiment in MV.
Contact: Juergen Kreyling
Typha and Phragmites offer options for sustainable agriculture of rewetted peatlands, i.e. paludiculture. In such rewetted systems, water table and nutrient level are controlled by management. Here, we will test for optimal water table and nutrient availability for the production of high-quality products.
Methods: Water table and nutrient levels are experimentally manipulated in a gradient-design mesocosm experiment at Greifswald. Here, quantity and quality of the produced biomass will be studied. In parallel, a field trial site will offer the option to compare to field conditions. Several topics for theses are available in this general setup.
13. Response of a coastal heathland to drought and grazing during different successional stages (BA or MA)
- Thema bereits vergeben -
Coastal heathlands are dominated by Calluna vulgaris. They are old cultural landscapes of high conservation value. However, atmospheric nitrogen deposition and management cessation have led to increased competition by grasses and woody species, thereby endangering this ecosystem type. In a field experiment on the island of Hiddensee, we test if climate change-induced drought would further exacerbate these developments and if (simulated) sheep grazing might retard it. All this is realized in two successional stages, one with young and vigorously-growing Calluna plants and the other with over-aged and partly dying Calluna. The whole experiment is part of the International Drought Experiment, a network which runs comparable drought experiments all over the globe.
14. Recovery after extreme drought in a coastal heathland (BA or MA)
Data sampling: Jul/Aug 2019
Location: Dünenheide Hiddensee
Contact: Juergen Kreyling, Irmgard Blindow
The extremely dry summer 2018 caused massive dieback of Calluna vulgaris and Empetrum nigrum in the coastal heathlands of Hiddensee. Extremes like this drought will happen more frequently with climate change. Recovery after the extreme is therefore crucial for the longterm perspective of this ecosystem type.
Methods: Visible damage and several plant parameters were monitored in August 2018 at about 100 plots. These plots shall be revisited to quantify recovery. In addition, about 30 visibly dead individuals were marked in September 2018 and recovery of those is also to be checked. Finally, aerial pictures from October 2019 can be used to quantify extant of the damage by remote sensing techniques and check recovery on the ground.
15. Presence and activity of soil mesofauna in drained and re-wetted peatlands (MA)
Date sampling: summer 2019
Location: Greifswald, potentially Uppsala (Sweden)
Contact: Gesche Blume-Werry
Soil mesofauna (e.g. springtails) are important components of the carbon cycle, as they feed on, and thus break down organic matter. Here, we want to assess the presence and activity of soil mesofauna in three different types of drained and re-wetted peatlands (alder carr, percolation mire and coastal mire). This project is within the framework of WETSCAPES, and is in collaboration with Eveline Krab from the Swedish University of Agricultural Sciences in Uppsala, Sweden. There is the potential to go to Uppsala to work on soil fauna identification.
Methods: Assessing presence of soil fauna, and their activity via bait lamina sticks. A driving license is a merit.
16. Importance of snow cover for understory plants in boreal forests
- Thema vergeben -
Snow cover is crucial for winter survival of boreal forest understory plants, as it protects them from severe air frost. With climate change, however, snow cover is getting thinner and less continuous. Here, snow cover is experimentally manipulated by snow-out shelters since 2002 in a boreal forest. Understory performance in this treatment can be compared to untreated reference conditions and a one-time manipulation of snow cover.
Methods: Determination of understory cover (higher plants and mosses) by point-intercept method in an existing field experiment.
17. Phenotypic plasticity and local adaptation in seedlings of Fagus sylvatica across Europe (MA)
Data sampling: August/September 2019 (field trip of up to 5 weeks)
Location: Experimental sites in Sweden, Germany, Poland, Switzerland, France and Spain.
Contact: Jonas Schmeddes
Phenotypic plasticity and local adaptations allow plant species to cope with heterogeneous environmental conditions in space and time. Therefore, knowledge on these two aspects is crucial for an estimation of potential adaptations of species to climate change. Here, potentials and limits of phenotypic plasticity and genetic adaptation in Fagus sylvatica are studied within an existing reciprocal translocation experiment within and beyond the current range of this species (Project A6 in DFG Research Training Group 2010 “RESPONSE”: Biological RESPONSEs to Novel and Changing Environments). The candidate will accompany the PhD-student to all sites. A driving license and driving experience is required. Travel costs are paid for.
Methods: Quantify juvenile growth and/or other functionally relevant traits in the existing experiment across sites in Sweden, Germany, Poland, Switzerland, France and Spain
19. Biomass production and trait variation of European wetland plants in response to mowing (MA)
Data sampling: summer/autumn 2019 (details to be discussed)
Location: M-V, possibly NW-Poland
Contact: Franziska Tanneberger
Within the European project REPEAT, biomass production and (below-ground) trait variation in response to mowing are studied. These rates are crucial for the evaluation of sustainable use of restored wetlands. Based on results in 2018, different mowing techniques (wheeled, tracked) will be compared within the same site(s).
Methods: Measurements of below-ground plant functional traits such as root porosity and environmental parameters such as soil compaction (using penetrologgers) before and after mowing.
20. „Strandwallfächer“ on the island of Hiddensee (1 MSc or 2 BSc)
- Thema bereits vergeben -
In the so-called „Strandwallfächer“ on the island of Hiddensee, coastal habitats, especially wet dune slacks, as well as shallow brackish biotopes inhabit a major number of threatened plant and animal species. The tasks, suitable for one master thesis or two bachelor theses, are to investigate higher plants as well as breeding birds, to identify threatened habitats according to the FFH habitat directives, and to recommend management measures for this area.
21. Change in location and composition of plant communities along an elevational gradient over a century in Abisko, Sweden
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Global warming is predicted to shift plant communities up mountains, as they follow their ideal temperature niche. Has this already happened? Or are plants able to adapt and stay where they are? Are new species coming in? We are re-visiting a transect in northern Sweden, where a botanist conducted vegetation surveys 100 years ago, to see if the plant communities changed their composition or location along the transect.
22. How representative is one transect of the plant composition of a whole mountain?
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Using historical vegetation data is a powerful tool to see if global warming has already changed plant communities, for example along transects in mountainous areas. This project tests whether a particular, historic, transect is representative of the plant communities on the whole mountain (and thus in the wider area).
Laufende und abgeschlossene Abschlussarbeiten:
Assessing root production in drained and re-wetted peatlands
(Nils Krauß, B.Sc.-Arbeit, betreut durch Jürgen Kreyling und Sarah Schwieger)
Einfluss von Trockenheit und Beweidung auf die Entwicklung der Heide auf Hiddensee
(Sara Zielke, B.Sc.-Arbeit, betreut durch Ilka Beil und Jürgen Kreyling)
Management options for the conversion of non-native coniferous forest patches towards more natural species composition in the Western Pomerania Lagoon Area National Park (Germany)
(Alex Seliger, Masterarbeit, betreut durch Juergen Kreyling und Michael Manthey)
Do volcanoes fertilize the globe?
(Vanessa Teike, Bachelorarbeit, betreut durch Juergen Kreyling und Ilka Beil)
Frost and drought tolerance in two provenances of a temperate weed (Anchusa arvensis)
(Kathrin Hölscher, Bachelorarbeit, betreut durch Andrey Malyshev)
Cross-stress memory: Influence of prior frost exposure on drought tolerance of a temperate weed
(Lena Hirschler, Bachelorarbeit, betreut durch Andrey Malyshev)
Variation der Frühjahrsphänologie bei Rotbuchen (Fagus sylvatica L.) unter Betrachtung der innerartlichen Konkurrenz
(Dennis Maß, Bachelorarbeit, betreut durch Juergen Kreyling & Ernst van der Maaten)
Inter-individual variation in spring phenology of european beech
(Aron Garthen, Bachelorarbeit, betreut durch Juergen Kreyling & Andrey Malyshev)
Effects of manipulated snow cover on fine root growth in beech forests varying in winter harschness
(Annika Behrens, Bachelorarbeit, betreut durch Robert Weigel & Juergen Kreyling)
Möglicher Zusammenhang zwischen Elektrolytgehalt und Tiefe der Knospendormanz
(Lena Möhlmann, Bachelorarbeit, betreut durch Andrey Malyshev)
Conditionally expressed heritability in Fagus sylvatica in a translocation experiment across Europe
(Stefanie Holm, Masterarbeit, betreut durch Juergen Kreyling & Lena Muffler)
Chasing aliens: The effects of non-native species removal on early stages of tallgrass prairie restoration
(Thea Courtial, Bachelorarbeit, betreut durch Hugh AL Henry & Juergen Kreyling)
Stressgedächtnis und lokale Anpassung verschiedener Herkünfte der Rotbuche (Fagus sylvatica L.) an Frost
(Zhuo Yang, Bachelorarbeit, betreut durch Juergen Kreyling)
Temperature dependence of heritability in Arabidopsis thaliana
(Dustin Koch, Masterarbeit, betreut durch Juergen Kreyling)
Using historical and phenological data to explain spatial and temporal variation in spring budburst dates of five tree species in Germany
(Jamal Uddin, Masterarbeit, betreut durch Andrey Malyshev)
Effects of snow cover on fine root growth in beech forests varying in winter harshness
(Christiane Klemm, Bachelorarbeit, betreut durch Robert Weigel)
Memory effects and intraspecific variation in stress response of Fagus sylvatica to recurrent drought events
(Phil Garthen, Bachelorarbeit, betreut durch Jürgen Kreyling)
Cross-stress tolerance and stress memory in perennial plants
(Alexander Wille, Bachelorarbeit, betreut durch Andrey Malyshev)
Bud dormancy and frost tolerance in trees – are they linked?
(Kathrin Bäthge, Masterarbeit, betreut durch Andrey Malyshev)
Die Auswirkungen verschiedener Winterbedingungen auf die Knospenzruhe und Knospenfrosthärte bei Fagus sylvatica
(Alex Kolb, Bachelorarbeit, betreut durch Jürgen Kreyling)
Root- and shoot phenology in different vegetation types
(Bo Peters, Masterarbeit, betreut durch Gesche Blume-Werry und Juergen Kreyling)
Influence of warm temperature on growth and development of Arabidopsis thaliana
(Matthias Lorenz, Bachelorarbeit, betreut durch Jürgen Kreyling und Ilka Beil)
Impacts of machine mowing on selected soil properties of near-natural fens - A case study from NE Germany
(Felix Nährmann, Masterarbeit, betreut durch Franziska Tanneberger und Juergen Kreyling)
Impacts of machine mowing on vegetation composition, root porosity and decomposition in near-natural fens - A case study from NE Germany
(Franziska Richter, Masterarbeit, betreut durch Elke Seeber und Juergen Kreyling)
Response of a coastal heathland to drought and grazing during different successional stages
(Anne Guthke, Bachelorarbeit, betreut durch Juergen Kreyling)
Importance of the three-spined stickleback (Gastrerosteus aculeatus) in the food web of two coastal shallow lagoons in the southern Baltic Sea
(Michael Steinmüller, Masterarbeit, betreut durch Irmgard Blindow)
Effects of snow cover on fine root growth in beech forests varying in winter harshness(Annika Behrens, Bachelorarbeit, betreut durch Robert Weigel und Jürgen Kreyling)
Within-species variation in leaf traits of Fagus sylvatica in response to macroclimatic site conditions
(Celia Baron, Bachelorarbeit, betreut durch Lena Muffler und Jürgen Kreyling)
Leaf and growth traits in different populations of Fagus sylvatica in response to drought
(Uday Sagar, Masterarbeit, betreut durch Jürgen Kreyling und Lena Muffler)
Stressgedächtnis und lokale Anpassungsfähigkeit verschiedener Herkünfte der Rotbuche (Fagus sylvatica L.) an Spätfrost
(Bibiana Kruse, Bachelorarbeit, betreut durch Lena Muffler und Jürgen Kreyling)
Veränderungen der Waldbodenvegetation entlang eines Temperaturgradienten in Buchenwäldern an neun Standorten in Deutschland und Polen
(Jennifer Gilles, Masterarbeit, betreut durch Robert Weigel und Jürgen Kreyling)
Developement of bud dormancy and cold tolerance in species with different chilling requirements
(Maren Hestermann, Diplomarbeit, betreut durch Andrey Malyshev)
Comparison of above ground and below ground autumn phenology in contrasting temperate vegetation types
(Sina Rogge, Masterarbeit, betreut durch Jürgen Kreyling und Robert Weigel)
Bestimmung der flächendifferenzierten Grundwasserneubildung eines holozänen Porengrundwasserleiters auf Hiddensee (Mecklenbeck-Vorpommern)
(Philip Hartung, Bachelorarbeit, betreut durch Maria Schafmeister und Irmgard Blindow)
Kalkinkrustierung verschiedener Characeenarten in Süß- und Brackwasser
(Levke Henningsen, Masterarbeit, betreut durch Irmgard Blindow)
Distribution of Zostera marina in the coastal waters of the Baltic Sea
(Anton Bühler, Masterarbeit, betreut durch Irmgard Blindow)
Der Einfluss meteorologischer Elemente auf das Blühverhalten ausgewählter Orchidaceae des Naturpark Schlaubetal
(Kai Hobritz, Bachelorarbeit, betreut durch Jürgen Kreyling)
Influence of soil-borne pathogens on seedling performance in declining Quercus suber forests: an experimental approach
(Vincent Hoeber, Masterarbeit, betreut durch Jürgen Kreyling)
Temporal bud dormancy and cold tolerance changes in trees
(Sascha Bock, Bachelorarbeit, betreut durch Andrey Malyshev)
Populations-spezifische Frosttoleranz vor und nach der Keimung von Fagus sylvatica
(Jan Moritz Böhme, Bachelorarbeit, betreut durch Jürgen Kreyling und Lena Muffler)
Allometric quantification of biomass in Calluna vulgaris
(Alexandra Nicola Effinger, Masterarbeit, betreut durch Jürgen Kreyling und Irmgard Blindow)
Fotoidentifikation von Meeresschildkröten auf Koh Tao, Thailand
(Lena Schenke, Bachelorarbeit, betreut durch Irmgard Blindow)
Plant stress memory: effects of recurrent drought and frost events on stress resistance in P lanceolata
(Molla Karimul Islam, Masterarbeit, betreut durch Andrey Malyshev)
Long term effects of a crude oil spill on desert vegetation
(Mara Nothers, Bachelorarbeit, betreut durch Jürgen Kreyling)
Effects of climate change induced autumnal warming on root phenology in the Arctic tundra
(Sarah Schwieger, Masterarbeit, betreut durch Jürgen Kreyling)
Zusammenhang zwischen frühlaichenden Amphibien und Habitateigenschaften von Kleingewässern auf der Insel Hiddensee
(Anna Sickert, Bachelorarbeit, betreut durch Irmgard Blindow)
Zusammenhang zwischen Gewässereigenschaften und Amphibien auf der Insel Hiddensee
(Lina Hartrampf, Masterarbeit, betreut durch Irmgard Blindow)
Beziehungen zwischen Zooplankton und submersen Makrophyten in der Darß-Zingster Boddenkette
(Maria Schiffler, Masterarbeit, betreut durch Irmgard Blindow)
Sedimentation und Resuspension in der Darß-Zingster Boddenkette – eine Methodenstudie
(Vivien Leonhardt, Masterarbeit, betreut durch Irmgard Blindow)
Composition and adaptation of submerged macrophytes in shallow coastal lagoons of the southern Baltic Sea
(Laura Schulz, Masterarbeit, betreut durch Irmgard Blindow)
Interaktionen zwischen suspendiertem Material und submersen Makrophyten in flachen Küstengewässern der südlichen und westlichen Ostsee
(Milena Kafka, Diplomarbeit, betreut durch Irmgard Blindow)
Zusammenhang zwischen Makrophytobenthos und Sedimentstruktur in flachen Küstengewässern der deutschen Ostsee
(Antje Kerkow, Diplomarbeit, betreut durch Irmgard Blindow)
Wechselwirkungen zwischen Phytoplankton, Nährstoffen und Submersvegetation an der deutschen Ostseeküste
(Caroline Lindner, Diplomarbeit, betreut durch Irmgard Blindow)
Interaktionen zwischen Zooplankton und submersen Makrophyten in den Boddengewässern vor Hiddensee
(Božena Nawka, Diplomarbeit, betreut durch Irmgard Blindow)
Potential und aktueller Stand der Kultivierung von Dreissena polymorpha zur Verbesserung des ökologischen Zustandes des Usedomer Sees
(Kristina Schulze-Böttcher, Masterarbeit, betreut durch Sven Dahlke)
Aktuelle Situation submeser Makrophyten und Diasporenreservoir im Usedomer See
(Elisa Domke, Diplomarbeit, betreut durch Sven Dahlke)
Means of communication and herbicide effects in predator-prey interactions between Scorpaena porcus and Pomatoschistus spp.
(Sandra Jahn, Diplomarbeit, betreut durch Claudia Kruschel und Irmgard Blindow)
Bereitstellungsketten von Landschaftspflegematerial zur energetischen Nutzung am Beispiel der Insel Hiddensee
(Sandra Grützmann, Bachelorarbeit (FH Stralsund), betreut durch Irmgard Blindow)