Theoretical Ecology

Our research focuses on theoretical community ecology and eco-evolutionary dynamics. We aim at developing a coherent and extensive theory bridging coexistence theory, the biodiversity ecosystem-functioning relationship, the architecture of ecological networks, and species coevolution. Our aim is to unravel and understand the key factor shaping the sustainability of ecosystems and their functioning.  Our research questions include:

  • How coexistence conditions are modulated by abiotic and biotic factors?
  • How these conditions impact ecosystems functioning?
  • How the architecture of interspecific interactions network effects coexistence conditions and ecosystem functioning?
  • What are the consequences of eco-evolutionary dynamic on coexistence, ecosystem functioning, and network architecture.

We combine field data and theoretical models to understand coexistence and coevolution and their implication on ecosystem functioning.


  • Structural approach to coexistence theory

    In Saavedra, Rohr et al. (2017), we formalise a multidimensional approach to coexistence theory: the structural approach. The aim of coexistence theory is to provide metrics for coexistence and then to study how abiotic and biotic factors impact those metrics. The structural approach extends the modern coexistence theory by going beyond pairwise interactions and by fully incorporating the indirect effects that emerge from multispecies interactions. We apply the structural approach to several systems such as mutualistic networks (2014, 2016), food-webs (2016, 2017), economy (2014). Recently, we provided a guideline to the structural approach for multi-trophic and changing ecological communities (2018).

    Graphical representation of the structural approach to coexistence theory. The angles Omega and theta define the structural niche and fitness difference (from 2017).


  • Ecosystem-functioning and biodiversity

    We aim at providing a mechanistic understanding of relationship between biodiversity and ecosystem-functioning (the BEF relationship). Using community dynamic models, we infer how species persistence, biodiversity, biomass production, and biomass distribution (evenness) are related (2016, 2018).

    Graphical representation of the relationships between species persistence, biomass distribution (evenness), and biomass production (from 2016).


    Recently (2018), we derived a mechanistic model to the BEF relationship. Its main advantage is the interpretation of the slope in terms of interspecific competition; the slope is inversely related to the average level of competition.

    The BEF relationship in natural microbial microcosms and its temperature dependence. Our mechanistic model predicts that a temperature increase results in higher levels of competition, which in turn, flatten the BEF relationship (from 2018).


  • Ecological networks

    Ecological networks depict the set of interspecific interactions among species in an ecosystem. We developed statistical models aiming at inferring, reconstructing, and predicting the architecture of networks (2010, 2016). Our latest model: the matching -centrality models aims at quantifying matching and centrality traits for each species. Those traits can be correlated to species traits and, then, used to reconstruct and forecast network structure (2016, 2017).

    The matching-centrality model (from 2016).

Our main collaboratros are Prof. Lous-Félix Bersier (Fribourg), Prof. Serguei Saavedra (MIT), and Prof. Nicolas Loeuille (Sorbonne University), and their group.

Rudolf Philippe Rohr

Lecturer, PhD, Group Leader

Office PER 01 - 0.361b
+41 26 300 8851

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Department of Biology

Chemin du Musée 10 
CH-1700 Fribourg