We operate an international seminar series on Theoretical Ecology via Zoom since September, 2020. With some exceptions, the hour-long events are held on every other Tuesday at 9 a.m. Pacific Time, which corresponds to 5 p.m. in London and 6 p.m. in Paris most of the time. Our invited lecturer speaks for cc. 20-30 minutes. The rest of the hour is for questions and discussions, which are often lively. The seminars are recorded and posted on our YouTube channel. We send out notifications before each lecture via email and Twitter. The webinar is organised by György Barabás (dysordys@gmail.com), Géza Meszéna (meszena.geza@ttk.elte.hu) and Chris Terry (christopher.terry@biology.ox.ac.uk). Any comment, or suggestion are welcome.
Zoom link (unless stated otherwise): https://liu-se.zoom.us/j/63158449287
YouTube channel with the lecture videos and teaching material, etc.
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Scheduled lectures
Gonzalo Robledo (Universidad de Chile, Chile): Sensitivity analysis for time varying ecological networks
4 November, 2025
We propose a generalization of the sensitivity analysis to press perturbations for ecological networksdescribed by time-varying ODE systems. The sensitivity analysis is a classical tood which has been successfully employed to assess the overall effects stemming from sustained changes in species growth rates on the equilibrium values of other indirectly related species in time invariant networks. Nevertheless, its generalization to the time varying case has remained elusive. Our generalization is based in two classical ODE topics: i) the smoothness of solutions of with respect to parameters and ii) the properties of exponential dichotomy and admissibility, which were combined with recent advances in the theory of non autonomous dynamical systems inspired on the new concept of non autonomous equilibrium and its local properties. We derive the sensitivity matrix as the solution of a non homogeneous linear matrix differential equation, which can be explicitly computed by using results from exponential dichotomy and admissibility. In addition, time averaging provides alternative characterizations for the sensitivity matrix in terms of the community one. This work has been made in collaboration with Rodrigo Ramos-Jiliberto (Universidad Mayor, Chile) and Daniel Sepúlveda (Universidad Tecnológica Metropolitana, Chile)
Violeta Calleja-Solanas (EBD-CSIC, Spain)
18 November, 2025
Ágnes Moréh (HUN-REN Centre for Ecological Research, Hungary)
2 December, 2025