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.
How to subscribe for email reminders?
Scheduled lectures
Violeta Calleja-Solanas (EBD-CSIC, Spain): The effect on stability of the temporal variability of species interactions
18 November, 2025
Despite increasing evidence of temporal variation in these interactions as a response to environmental conditions, most theoretical frameworks remain rooted in static assumptions. Little is known about the feedbacks between demographic and ecological processes that structure the temporal dynamics of communities, but understanding these processes is fundamental to better predict the fate of ecological communities under continuous variation of external drivers. Here, I will present an ecological framework with temporal networks thanks to rich multi-annual datasets subjected to interannual changes in rainfall, obtaining signed directed and weighted interactions. Environmental anomalies produce contrasting effects on the temporal networks’ structure, the opportunities to coexist, and the species’ overall performance.
Ágnes Moréh (HUN-REN Centre for Ecological Research, Hungary): Simultaneous invasion by two species: consequences for their success and for the resident community
2 December, 2025
While numerous studies have investigated the interactions between invasive and native species, less attention has been given to the relationships among invasive species themselves and to how these interactions influence both their own success and their collective impact on resident communities. In this theoretical study, we compared the invasion outcomes of two non-native species under two scenarios: separate versus simultaneous invasion of resident food webs. Using dynamic simulations based on the Allometric Bioenergetic Model, we assessed invasion success (presence or absence of invaders), biomass changes, diversity loss (number of extinctions), and total community biomass. We explored how the invaders’ direct and indirect ecological relationships and their topological positions in the food web (trophic level, top/intermediate position) affect both their invasion success and the additive or non-additive nature of their combined effects on the community. Our results demonstrate that direct interactions such as predator–prey relationships can increase the probability of invasion success for both invaders but may reduce the equilibrium biomass of one or both compared to separate invasions. Competitive interactions tend to hinder co-invasion success, whereas trophic cascades or shared predators can lead to synergistic effects on the resident community. We further found that higher trophic positions generally reduce invasion success regardless of the presence of another invader. These findings integrate food web topology with invasion dynamics and provide a theoretical framework that helps interpret and complement results observed in field and mesocosm systems.