The following is a list of potential projects for research practicals in plant diversity, bachelor projects or master projects. However, these are only a selection of ideas and other projects are also possible, so if you have an idea for a project that addresses some aspect of biodiversity (coexistence, global change, biodiversity-functioning) then email Eric Allan to discuss it.
Research practical in plant diversity: this is worth 7.5 ECTS and is around four weeks of work. Students carry out a small research project of their own, which can involve running a greenhouse experiment, collecting data in the field (only in the spring semester), or analysing or identifying samples in the lab, e.g. insects, soil analysis. Students therefore get an overview of all stages of research, including designing a study, collecting plant ecological data, analysing data and writing a report. The report is structured like a scientific paper with introduction, methods, results and discussion. The work can be done flexibly and therefore spread out over a semester, although if you are running a greenhouse experiment you will probably have to commit to taking measurements at a certain time when plants need to be harvested.
Bachelor projects are similar to research practicals but are worth 10 ECTS and therefore constitute around 5-6 weeks of work. This allows a larger project to be carried out.
PaNDiv Experiment: direct and indirect effects of N enrichment on ecosystem functioning and pathogen communities
Who: Research practical, master student or bachelor student
With: Eric Allan and PhD students, depending on the project
Start: Spring or summer, most field work runs from beginning of May to end of August
Background: Humans are causing a range of environmental changes that threaten biodiversity and alter the services provided by ecosystems. Nitrogen (N) enrichment, from agricultural runoff or atmospheric deposition, is one of the most important environmental changes in European grasslands and it has many effects on the ecosystem. It changes soil chemistry and directly increases plant growth. At the same time, it causes loss of biodiversity, a shift towards faster growing plant species and often an increase in the abundance of herbivores and foliar fungal pathogens. Foliar fungal pathogens are abundant in grasslands, and they can reduce biomass, but we know very little about their effects on ecosystem services. All of the changes which occur with N enrichment might affect the services provided by grasslands but we still don’t know how important the different effects are and how they might interact with each other.
The study: To answer these questions, we established a large grassland field experiment to test which mechanisms explain the effect of N enrichment on ecosystem function. The experiment manipulates N addition (0, 100kg N ha-1, y-1), species richness (1, 4, 8, 20 species), functional composition (only fast growing, only slow growing or a mix of species) and fungal pathogens (foliar fungicide or not). Many ecosystem functions and services have been measured including biomass production (above and belowground), pathogen infection and herbivory, soil carbon, soil nutrients, soil respiration and litter decomposition.
Potential projects: There are many options for student projects in the experiment. For instance projects could:
- Measure root production and respiration using ingrowth cores. These can also be used to exclude mycorrhizae to measure mycorrhizal respiration
- Measure different fractions of soil carbon to assess effects on short and long term carbon storage
- Use molecular methods to characterise the pathogen community and identify fungal pathogens in leaves
- Assess functional diversity of soil microbial communities using BIOLOG plates
- Use soils from the experiment to conduct feedback experiments in the greenhouse
- Many other options
Bug-Network: A global collaborative research network that aims to better understand the impact of invertebrate herbivores and pathogenic fungi on plant communities and ecosystems
Background: Invertebrate herbivores and fungal pathogens can strongly affect the diversity, structure and functioning of plant communities. However, we still have a limited idea of how generally important they are. One reason for our lack of knowledge is that the impact of consumers is likely to vary across environmental gradients. Lots of ecological theories have suggested that enemy impact depends on abiotic conditions at large spatial scales such as climate (latitude, altitude) and plant productivity, but also on abiotic and biotic drivers operating at smaller spatial scales, such as plant diversity and soil fertility (bottom-up) and predator abundance (top-down).
Our understanding of how consumer communities and their impact varies across environmental gradients is surprisingly limited. Existing studies differ substantially in methodology, making generalities across large scales difficult, which calls for comparative approaches that implemen standardised protocols across sites. This is particularly important if we are to understand how globa change drivers, such as climate and land use change, will alter consumer communities and their functioning.
The study: A powerful tool to quantify the variation in plant consumer communities and their impact are globally coordinated experiments, using standardized measurements and replicated experiments across ecological gradients. The “Bug-Network” will be such a project and aims to explore the general effects and context dependency of biotic interactions within a coordinated research network comprised of many grassland and shrubland sites worldwide. The BugNet has just started!
BugNet consists of a comparative part and an experimental part. For the comparative part we will characterize different plant communities and at the same time sample their invertebrate communities in different grasslands in Switzerland and elsewhere in Europe. We aim to test whether changes in the structure of invertebrate communities are driven by climatic factors or via changes in the plant community. For the experimental approach we will install a field experiment where we will exclude insects, fungal pathogens and molluscs using pesticides. We will observe how the plant community changes in response to enemy removal. The comparative part and the experimental parts will be replicated in many parts of the world – which offers exciting possibilities to answer pressing questions in community ecology.
You can find more information on the BugNet project on the website: bug-net.org
How do soil fungi responses to global change drivers feed back on plant performance?
With: Nadia Maaroufi
Who: Bachelor or master students
What: Plant-soil feedback greenhouse experiment using soil inoculum collected in the PaNDiv Experiment
Start: late summer 2021
Background: Nitrogen addition together with plant biodiversity loss and changes in plant functional composition are global changes that are known to impact ecosystem functions and services in grasslands. These global change drivers can directly affect soil properties by for instance, affecting soil nutrient balances or indirectly by impacting plant litter quantity and quality; and thus the primary resources fueling soil organisms. Soil organisms such as soil microbes (fungi and bacteria) play a critical role in regulating ecosystem processes involved in plant growth, plant litter decomposition, soil organic matter turnover and nutrient cycling. Very little is known about how the changes in soil microbial communities, in response to global change drivers, feed back to affect plant performance.
The study: The PaNDiv Experiment, which factorially manipulates nitrogen addition, plant species diversity, functional composition (fast vs. slow growing species) offers a great opportunity to study the impact of these global change drivers on plant-soil feedback in grasslands. The aim is to select plant communities that will differ in their nitrogen enrichment, biodiversity and plant functional composition and that would simulate different management practices, for example, monoculture of fast growing species used in forage crop: Lolium perenne. Soil originated from each treatment will be processed to get soil inoculates that will be used in a greenhouse experiment. Pots will be filled with sterilized soil that will be inoculated with soil microbiota originated from the selected plant communities. Pots will be planted with plant seedlings with target plant species. Plant survival, growth, above- and below-ground biomasses as well as metrics of plant-soil feedbacks will be calculated. The fungal traits: degree of fungal root colonization and pathogen infection will be measured at the end of the experiment.