Abstract: What characterizes species-rich communities with complex species interactions--for example, competing over many niches? Models predict sharp transitions, as conditions are changed, between qualitatively different dynamical behaviors. These include the abrupt appearance of a vast number of alternative steady-states; and the onset of persistent abundance fluctuations, nearly uncorrelated between species. We discuss these phenomena, and […]

Abstract: Matching habitat choice and local adaptation are two key factors that control the distribution and diversification of species. We study their joint evolution in a structured metapopulation model with a continuous distribution of habitats. Habitat choice follows from dispersal with non-random immigration, a process always acknowledged yet rarely incorporated into theoretical models. For fixed […]

Abstract. Can alternative stable states arise when food webs dissipate feedbacks across many species in diverse systems like coral reefs? Although consumer loss often characterizes degraded ecological states, food web resilience theory predominantly focuses on specific systems and few-species models. After developing a generalized model of consumer collapse, we show that alternative stable states dominated […]

Warning! During this week the time difference between America and Europe is one hour less, than usual. The seminar will begin at 9 am Pacific, as always, but now it will correspond to 4 pm in London and 5 pm in Paris. Abstract: Dynamic models of ecological communities that neglect within-population structure predict that stability […]

Warning: this is a Monday! Abstract: In the 1980s, Josef Hofbauer introduced a criterion for mathematically verifying coexistence using per-capita growth rates of species when rare i.e. Lyapunov exponents. This criterion ensures coexistence is robust to large perturbations of the community state (i.e. permanence) and small structural perturbations of the governing equations (i.e. robust permanence). […]