Below is a list of topics for B.Sc. or M.Sc. theses. If you are interested in doing your research in our group the procedure is as follows:
go through the list and topics and find what you are interested in
contact the direct supervisor by email and ask for more information
make an appointment with your direct supervisor to discuss the topic, timeframe etc. in more detail
if you have found a topic that you would like to choose there will be a meeting between your direct supervisor, yourself and W. Weisser, to discuss the design of your study, starting dates, financial aspects and other formalities.
you develop a thesis plan that will be part of the formal agreement between yourself, your direct supervisor, and W. Weisser for the thesis
If you are interested in a topic that is not listed below or if you have any other question please feel free to contact W. Weisser or any other person in the group.
Diversität beeinflusst die Funktion und erbrachte Dienstleistungen von Ökosystemen. So haben ökologische Experimente vielfach gezeigt, dass in Ökosystemen Pflanzenvielfalt die Diversität anderer Organismen und Produktivität (neben anderen Funktionen) erhöht. Um in der Landwirtschaft diese Ergebnisse aus der ökologischen Grundlagenforschung zur Verbesserung der Produktion und Abmilderung von Umweltbelastungen anzuwenden, bedarf es weiterer Forschung. In einem Freilandversuch am Rand des Campus in Freising untersuchen wir die Auswirkungen der Artenvielfalt in einem Feldfuttersystem auf Ertrag, Futterqualität und ökologische Parameter. Das Experiment wurde auf 60 Parzellen in 2020 etabliert und kann dieses Jahr für vielfältige Fragestellungen und Messungen in studentischen Abschlussarbeiten genutzt werden.
Master thesis in Forest Ecotoxicology – Summer semester 2021
Outbreaks of the gypsy moth Lymantria dispar can cause profound alterations of forest ecosystem by causing complete defoliation of trees and increasing tree mortality. Defoliation can also harm insect herbivores by reducing food availability, increasing the production of plant defense chemicals, and stimulating the development of secondary pathogens such as the powdery mildew.
Gypsy moth outbreaks are combatted by forest managers with aerial applications of insecticides that can also negatively affect non-target herbivores. Risk assessment protocols focus on testing the toxicity of a pollutant to organisms and rarely take into consideration how their life histories may mediate their exposure to the toxicant. Knowledge of a population’s ability to avoid exposure (avoidance traits) and recover following exposure (resilience traits) should be combined with results from toxicity assays to the risk posed by insecticides to individual species.
We are interested in testing separately the impacts of gypsy moth outbreaks and insecticide treatments on two important guilds of oak herbivore: leaf-miners and gall-inducers. Oak leaf samples were collected in 48 oak forests in Northern Bavaria, 24 of which sustained gypsy moth outbreaks in 2019, while the other 24 had normal endemic densities. Half of the plots in each group was sprayed with the insecticide tebufenozide and the other half left unsprayed (full factorial design). The master’s thesis work comprises of the following steps:
Identification to genus/species of leaf-mining and gall-inducing insects on the leaves
Scoring of chewing damage
Statistical analysis of the data
Prospective students should have interest in forest ecology, entomology or ecotoxicology and have a good command of the English language. If the work is successful, the results may be published in an international peer-reviewed scientific journal.
Landwirtschaftliche Nutzung kann Biodiversität fördern oder verringern und selbst von einer erhöhten Biodiversität profitieren. Hopfen ist eine wichtige Nutzpflanze und ist in Regionen wie der Hallertau die wichtigste Kultur in der Landwirtschaft. Während Hopfenanbaumethoden in den letzten Jahren stark verbessert wurden, haben viele ehe-mals für den Hopfenanbau typische Arten wie das Rebhuhn, Tagfalter wie der C-Falter oder das Tagpfauenauge, oder auch Heuschrecken und Netzflügler in den Hopfenanbauregionen abgenommen. In der Masterarbeit soll fol-genden Fragen nachgegangen werden:
Was sind die wahrscheinlichen Mangelfaktoren, die zu dem Rückgang von typischen Arten geführt haben? Zielarten sind das Rebhuhn (Perdix perdix), die Heidelerche (Lullula arborea), der C-Falter (Nymphalis c-album), der Hopfen-Taghaft (Hemerobius humulinus), das Grüne Heupferd (Tettigonia viridissima), die Ei-chenschrecke (Meconema thalassinum) sowie weitere Tagfalter und andere Arten. Mit Hilfe einer Literatur-studie sollen die Mangelfaktoren (z.B. Nahrungsverfügbarkeit, Deckung, Insektizide usw.) für die verschie-denen Arten herausgearbeitet werden.
Gibt es Unterschiede im Vorkommen der Zielarten zwischen ökologisch und konventionell bewirtschafteten Flächen? In eigenen Aufnahmen soll das Vorkommen der Zielarten im Freiland quantifiziert werden. Neben dem Ver-gleich zwischen ökologischen und konventionellen Flächen soll auch eine Bestandsaufnahme in größeren (je 1-2 km2) zusammenhängenden Bereichen mit überwiegendem Hopfenanbau erfolgen.
Welche Maßnahmen könnten das Vorkommen der Arten in Hopfenanbaugebieten fördern? Auf Basis der eigenen Untersuchungen sollen Vorschläge gemacht werden, wie die Diversität im Hopfen gefördert werden kann. Die Vorschläge dienen als Vorlage für zukünftige experimentelle Maßnahmen.
Die Arbeit wird gemeinsam von der TUM (Lehrstuhl für Terrestrische Ökologie, Prof. Wolfgang W. Weisser) und der Landesanstalt für Landwirtschaft (Hopfenforschungszentrum Hüll, Dr. Florian Weihrauch) betreut. Reisekosten für die Freilandarbeiten können erstattet werden.
Intensification of land use is the main factor for the loss of biodiversity in grasslands. Aside from lower species richness, the composition of the community changes. Species with low dispersal ability are especially threatened. In the Bachelor/Master-thesis, sweep-net samples taken before and after a mowing event will be analysed to find out whether the communities’ dispersal ability changes after the mowing event.
Modern ecological research often investigates into the relationships between ecosystem functions (the processes contributing to element cycles, functioning and regeneration of ecosystems) and different regulating factors (e.g. diversity, land use, (human) disturbance, environmental conditions). For such studies the ability to quantify ecosystem functions using suitable indicators is essential. In this Bachelor- (Master-) thesis a selected function (or combination of functions) will be measured with different techniques and their suitability as indicator for the function will be assessed.
Ecosystem functions along an experiment diversity gradient
The Jena Experiment (www.the-jena-experiment.de) studies in a large-scale field experiment the functional importance of biodiversity. We aim to study whether changes in ecosystem functions (decomposition, predation, pollination, seed dispersal) due to plant diversity can be directly measured. To do so, suitable indicators will be measured in the plots of the Jena Experiment in a standardized fashion to quantify functions and investigate their relationship with plant diversity. Within a Master thesis several different functions, or in a Bachelor thesis a single function (as in the example below) can be studies. Also several complementary Bachelor theses are possible.
Feeding assays to characterize host choice of abundant herbivores
Previous studies in the frame work of the Jena Experiment (www.the-jena-experiment.de) have identified important herbivores that occur abundantly on the plots of the experiment. For many of these species little is known about their host range. In this Bachelor project the suitability of the 60 plant species forming the species pool of the Jena Experiment as host plants for a range of the important herbivores shall be tested. Preferences will be assessed in feeding trials conducted in the laboratory.
Animal diversity and ecosystem functions on urban squares: effects of tree diversity and square characteristics
Cities are habitats for humans but are also highly dynamic ecosystems that harbor a big variety of common and rare animal species. These species are dependent on green infrastructures and the resources they provide. At the same time green infrastructures and their contained biodiversity provide several ecosystem functions and services for humans. Growing cities face multiple challenges for biodiversity and so its conservation has to move in the focus of urban planning. To plan urban squares as functional green infrastructures it is essential to know which characteristics are influencing biodiversity and provided ecosystem functions. The offered master thesis will monitor components of biodiversity or quantify selected ecosystem functions on 100 urban squares in Munich and investigate their dependence on provided characteristics of the squares in the framework of a larger interdisciplinary project.
Biodiversity surveys in forest ecosystems disproportionately favor legally protected areas. However, these nature reserves constitute only a small fraction of the total forest area. We are interested in assessing the effects of integrative forestry on several taxonomic groups. Integrative management is an attempt to reconcile the use of natural resources with the conservation of biodiversity. Birds are highly dependent from the structural quality of their habitat and at the same time highly mobile, making them a well-suited study object. Our study region is a large, connected forest area in northern Bavaria with up to 53 breeding bird species and some of Germany's oldest beech stands. As part of a larger biodiversity survey, the Master's thesis will comprise a series of bird surveys during spring 2017. Prospective students should possess ample knowledge of local forest bird species and some experience in bird mapping, as well as their own means of transportation and an interest in forest ecology.
