Open Master Theses ¶
There are several open Master theses in the forest entomology group, if interested, please contact the person mentioned in the respective description.
We are open to applications for Bachelor's theses, and, subject to agreement, it may be possible to convert a Master's thesis work into a Bachelor's thesis work.
Contents ¶
- Global change effects on decomposer communities and decomposition
- Do trees possess a drought memory and does it affect tree-feeding insects?
- Does artificial night light colour affect plant volatiles and does this impact insect pollinators?
- How does drought memory in trees shape multi-trophic interactions?
- Change of food-web structure and food-chain length in response to ecosystem engineering by beavers
- Succession of arthropod diversity and species traits after the forest fire in Leuk
- Effects of Artificial Light at Night (ALAN) on Floral Nectar Traits and Surface Optical Properties in Silene
- Effects of artificial light at night on aquatic-terrestrial arthropods
Global change effects on decomposer communities and decomposition ¶
We proposed a global protocol to assess human impacts on forest ecosystems using experimental microcosms. The main question we aim to address is: How do current and future climatic conditions, forest habitat degradation and management, influence biodiversity and ecosystem functioning in water filled microcosms worldwide? In the Master's thesis offered, you will assess and analyse data of this global experiment with a focus on Swiss study sites. This will increase our understanding of the impacts of global change drivers on ecosystem functioning in Switzerland. Recommendations for stakeholders and practitioners will be derived. No field work is required, but it is possible to conduct a small experiment and visit the places where we collected the data. Also identification and measurements of insect larvae from additional samples is possible. There is the opportunity to contribute your own ideas.
Supervisor: Prof. Dr. Martin Gossner
Requirements: Bachelor’s degree in biology, ecology, or environmental sciences; strong interest in ecosystem relationships; fluent in German and/or English; eager to work with insects and do statistical analyses; experience in statistics and R is advantageous and necessary.
Finance: no additional costs
Contact (E-Mail): martin.gossner(at)wsl.ch
Projekt-Website: MICROcosm Protokoll (PDF)
Do trees possess a drought memory and does it affect tree-feeding insects? ¶
Extreme droughts can have long‐lasting effects on forest community dynamics and species interactions. There is increasing evidence that trees that have experienced extreme drought effects in the past show differences in their leaf chemical profile compared to trees that have not been exposed to drought. Such “drought memory” effects are likely modulating the interaction between trees and insect herbivores whose community composition and performance is driven by leaf chemistry. Yet, our understanding of how drought memory effects on tree chemistry modulates ecological relationships between trees and insects is just unfolding.
The Msc student will have the opportunity to make use of a large drought stress experiment near Munich. You will collect insects and compare the insect communities in European beech trees that have previously been experimentally drought stressed with trees that have not been exposed to drought. Optionally you may also conduct experiments with caterpillars and aphids to test if insects perform differently on previously drought-stressed trees vs. non-stressed trees. The study will be conducted in late spring 2027. You should have a strong interest in plant-insect interactions and insect taxonomy (sorting of sampled insects will be required). Also, you should not be afraid of heights as you may be working in a canopy crane. Basic skills in statistics with R are advantageous.
Supervisor and Co-Supervisors: Prof. Dr. Martin Gossner, Dr. Lydia Dean, Dr. Michael Eisenring
Season: Late spring 2027
Abroad: yes
Finance: travel costs will be covered
Contact (e-mail): michael.eisenring(at)wsl.ch
Does artificial night light colour affect plant volatiles and does this impact insect pollinators? ¶
Light pollution caused by Artificial Light at Night (ALAN) raises numerous ecological issues. In this MSc project you are exploring how the spectral composition ("light color") of artificial night light influences plant chemistry and plant-insect interactions. Our objective is to determine how LED color alters diurnal and nocturnal phytochemistry and how these changes affect plant-insect interactions. You will study two common plants; meadow sage and white campion which differ in insect communities and pollination strategies. Combining fieldwork with climate chamber experiments, you will examine LED color effects on volatile and/or non-volatile plant chemistry and its consequences for pollinators and/or different herbivore feeding guilds. By addressing this knowledge gap, your research will support the development of optimized, sustainable outdoor lighting strategies.
The study will be conducted in late spring/summer 2027. You should have a strong interest in plant-insect interactions and laboratory work. Basic skills in statistics with R are advantageous.
Supervisor and Co-Supervisors: Prof. Dr. Martin Gossner, Dr. Michael Eisenring, Carlotta Zamboni
Season: Spring, Summer 2027
Abroad: no
Contact (e-mail): michael.eisenring(at)wsl.ch
How does drought memory in trees shape multi-trophic interactions? ¶
Extreme droughts can have long‐lasting effects on forest community dynamics and species interactions. From the bottom-up, there is evidence that prior drought can alter leaf chemistry and plant quality, potentially mediating interactions between plants and herbivores. From the top-down, predators (i.e. insectivorous birds) play an important role in benefiting plants by controlling herbivore populations. However, how predators may be directly and indirectly impacted by prior drought exposure within these interactions is not yet well understood, which has implications for arthropod community structure and plant defense. The aim of this project is to understand if prior drought exposure modulates multi-trophic interactions and disentangle the mechanisms by which this may occur.
The MSc student would have the opportunity to make use of a large drought stress experiment near Munich to explore these multi-trophic interactions. You would conduct predator foraging assays using clay caterpillars (pictured) in European beech trees that have previously been experimentally drought stressed with trees that have not been exposed to drought. You could conduct further experiments on the top-down (predator e.g. birds) and bottom-up (drought/plant) mechanisms of this interaction through laboratory and greenhouse experiments (e.g. bird exclusions, predator assays, herbivore assays, plant leaf analysis). The study will be conducted in late spring 2027. Also, you should not be afraid of heights as you may be working in a canopy crane. Basic skills in statistics with R are advantageous.
Supervisor and Co-Supervisors: Prof. Dr. Martin Gossner, Dr. Lydia Dean, Dr. Michael Eisenring
Season: Late spring 2027
Abroad: yes
Finance: travel costs will be covered
Contact (e-mail): michael.eisenring(at)wsl.ch
Change of food-web structure and food-chain length in response to ecosystem engineering by beavers ¶
The presence of beavers influences ecosystems and therefore species composition and interactions. As biodiversity at multiple trophic levels is important for the multifunctionality of ecosystems, changes in community composition and species interaction networks (food-webs) will likely challenge ecosystem functioning and stability. Understanding and predicting these effects is important, especially in complex blue-green habitats, where aquatic and terrestrial communities are interconnected, but might respond differently. This project aims to reconstruct food-webs in beaver ecosystems via bulk and/or compound-specific stable isotope and fatty acid analyses. In order to answer these questions, we have collected species data in beaver systems in Switzerland. Within the frame of the Master thesis taxa (species or higher) will be identified and stable isotopes and fatty acids will be analysed in the lab. The ultimate goal is to analyse changes in food-web structure and food-chain length in response to ecosystem engineering by beavers.
We offer an MSc project in the Forest Entomology Group in collaboration with the Community Ecology Group at WSL (part of the ETH domain) in Birmensdorf. The MSc project is part of the Blue Green Biodiversity research initiative of WSL and Eawag. The student acquires taxonomic knowledge about invertebrates and learns how to carry out stable isotope and fatty acid analyses as well as food web analyses. The study is independent of the growing season.
Supervisor und Co-Supervisor: Prof. Dr. Martin Gossner und PD Dr. Anita Risch
Requirements: You should have a strong interest in laboratory work and statistical analysis and preferably already have knowledge of stable isotopes. Basic knowledge of statistics with R is an advantage.
Contact (E-Mail): martin.gossner(at)wsl.ch
Succession of arthropod diversity and species traits after the forest fire in Leuk ¶
In 2003, an extensive forest fire consumed over 300 hectares of woodland on a mountain slope near Leuk, Switzerland. This event stands as one of the most significant fire incidents of the past century in Switzerland, resulting in the near-complete elimination of all aboveground plant and most arthropod life across various forest ecosystems within the elevation range of 900 to 2100 meters above sea level. In response to this ecological disruption, pitfall and flight interception traps were established in the center, at the edge and in intact surrounding forests at different elevation. Over subsequent intervals of one, two, three, four, ten, and twenty years following the fire, the changes in arthropod communities were monitored.
The primary objective of this master's project is to analyze the temporal changes in species and functional diversity and to identify trait shifts along the succession after the disturbance. Therefore, a target group will be selected and identified to species level with the help of taxonomic specialists. Subsequently, the succession of diversity and traits will be modelled using an appropriate statistical framework.
Supervisor und Co-Supervisor: Prof. Dr. Martin Gossner und Dr. Marco Moretti
Requirements: You should have a strong interest in biodiversity and insects. Skills in statistics with R are advantageous.
Contact (E-Mail): martin.gossner(at)wsl.ch
Effects of Artificial Light at Night (ALAN) on Floral Nectar Traits and Surface Optical Properties in Silene ¶
Artificial light at night (ALAN) is an increasingly widespread anthropogenic disturbance that alters plant physiological processes and disrupts nocturnal ecological interactions. While the broader ecological impacts of light pollution are recognized, the specific mechanisms by which ALAN modulates floral rewards and visual cues remain understudied.
Using the nocturnal genus Silene (Caryophyllaceae) as a study system, this project investigates how exposure to controlled ALAN conditions influences nighttime nectar production (volume and sugar concentration). To capture a holistic view of treatment-driven variation in floral phenotypes, traditional nectar assays will be complemented by floral surface hyperspectral imaging to quantify changes in reflectance profiles.
Work Breakdown:
- 50% Experimental Fieldwork: Managing plant exposure to controlled ALAN setups and collecting samples in Uitikon, potentially supplemented by greenhouse or climate chamber assays.
- 20% Lab & Technical Work: Conducting fine-scale nectar assays alongside hyperspectral imaging to analyze floral surface optics. Prior experience with chemical analysis or imaging software is not required.
- 30% Data Analysis & Writing: Processing hyperspectral image cubes, managing project data, and performing statistical modeling in R to prepare the final thesis.
Core Hypotheses: The project aims to test three central ideas. First, that ALAN treatments alter baseline nectar volume and sugar concentration in Silene. Second, that these light treatments alter the floral reflectance profiles in ways that change how insect pollinators perceive the color of the flowers, based on their specific photopigment sensitivities. Finally, the project will assess whether the magnitude of effects on floral rewards correlates with changes in optical traits, indicating broader phenotypic disruption.
Requirements: We are looking for a student with a strong interest in plant ecology, physiology, and the impacts of anthropogenic environmental change. The candidate should be willing to undertake field-based experimental work and maintain a meticulous approach to collecting delicate floral measurements and handling imaging equipment. Basic statistical skills in R are desirable. Prior experience with chemical analysis or imaging software is not required, as full methodology training will be provided.
Season: Summer 2026
Contact: PD Dr. Janine Bolliger (janine.bolliger(at)wsl.ch), Federico Ferrari (federico.ferrari(at)wsl.ch).
More information about the forest entomology group can be found with QR Code on top right.
Effects of artificial light at night on aquatic-terrestrial arthropods ¶
Project Description
Research question: How does artificial light at night (ALAN) influence arthropod community structure, behaviour, movement (biomass fluxes) and/or ecosystem processes?
Rationale: ALAN influences various arthropods, but very little research has focussed on aquatic-terrestrial ecosystems (e.g., stream-riparian zones) and the abundance/biomass fluxes between them.
Thesis: You will perform lab or field experiments under (different coloured) ALAN and assess its effects on the ecology of various arthropods on land and water. You are highly motivated to analyse ecological data statistically and have experience with R. You are scientifically creative and interested in the ecological consequences of human disturbances on nocturnal wildlife. Starting time can be agreed upon but note that this will affect what ecological questions can be asked specifically.
Collaborators: Rebecca Oester, Jörg Haller, Martin Gossner, Janine Bolliger
Contact: rebecca.oester(at)wsl.ch