Computer-based work (strong literature review component)

1.   Individual-based models vs mean-field approach: what do we need?

Topic: In ecology and sociology, the huge variability in behaviour and the large variability in any trait of relevance among individuals has led to a strong push for so-called "individual-based" models, aka "agent-based models". These represent individuals, with fixed traits, but large variation among individuals. Such IBM/ABMs contrast with traditional, "theoretical" models, which are referred to as "mean-field approaches" (MFA).

It can be easily shown, for hypothetical situations, that IBM and MFAs may differ substantially in population dynamics. But does this potential difference actually matter in real systems?

Methods: Literature review of all studies comparing IBM and MFA. In google scholar, "("individual-based model" or "agent-based model") AND "mean field"" yields just over 200 papers, most probably irrelevant.

Suitable as: BSc or MSc thesis project

Time: A start is possible at any time.

Requirements: Interests in rather abstract system descriptions and model behaviour; meta-analysis.

Contact: Carsten Dormann, carsten.dormann@biom.uni-freiburg.de

2.   Are arthropod communities on trees more strongly determined by tree age or tree species identity? [Literature review with strong quantitative analysis component; multivariate statistics in R]

Topic: Tree diversity experiments, such as the IDENT site in Freiburg, allow clear conclusions about effects of biodiversity and tree species combinations on ecosystem functions, and the underlying mechanisms. But given the relatively small scale of such experiments, it can be challenging how to transfer results to real-world forests.
In the tree diversity experiment IDENT-Freiburg, we have sampled arboreal arthropods over several years now, revealing how biodiversity affects herbivory and arthropod communities.

Aim / Methods: The aim of this thesis is to compile arthropod community data from the literature for the same tree species as planted in the experiment, and compare community composition between the data from the IDENT experiment and data from literature sources with varying tree age. This involves literature search, data extraction and data analysis.

Requirements:
Interest in community ecology and entomology. Some experience with R, ideally with analysis of biodiversity / community data.

Time: project can start anytime. Suitable as BSc or MSc project.

Contact: Jochen Fründ (jochen.fruend@biom.uni-freiburg.de)