Population cycles: causes and consequences of oscillations in population size

par Dr Frédéric Barraquand (Institut de Mathématiques de Bordeaux)

mardi 5 déc. 2017, 11:00 → 12:00 Europe/Paris

432 (4ème tage) (INRIA- antenne Lyon- La Doua, Bâtiment CEI-2 (tram: T1-IUT FEYSSINE))

Regular, partly periodic oscillations in the size of animal and plant populations are believed to be widespread in ecosystems ranging from the tundra to the oceans, affecting about a third of monitored populations. These fluctuations can have large amplitude, so that population size varies across several orders of magnitude. Numerous mechanisms, most notoriously interactions between predator and prey or diseased and healthy individuals are known to promote oscillatory phenomena but the causes of cycles in most wild populations remain unknown. In this talk, I will outline how this problem has developed over the years in ecology, as well as recent modelling trends in research into the causes (and consequences) of such widespread variation in population size, using varied examples from mammals to plants. We will see in particular how current research tends to move away from the now classic bivariate oscillators to embrace high-dimensionality, seasonal and stochastic forcing, as well as demographic intricacies.