My research mainly revolves around the following three themes:
Tipping points in ecological networks
It is becoming increasingly clear that in many cases complex systems, as for example ecosystems, have tipping points at which they respond abruptly to small changes in external drivers. In addition, the ability of identifying such tipping points is hindered by our limited understanding of the underlying complexity for most of these systems. Lastly, almost none of these systems exists in isolation, but all are part of a network of interacting and interdependent elements. Major implication of these three observations is the increased uncertainty when it comes to the management of complex systems, because crossing a tipping point in one part of the system may lead to a cascade of transitions in another. As this risk is even greater under present rates of global environmental deterioration, my aim is to improve our capacity for understanding and anticipating tipping events in ecological networks.
Acknowledging the existence of critical transitions is only the first step for avoiding them. It would be tremendously valuable, if we could predict when a critical transition will happen. Unfortunately, for most systems, we neither have enough records of past transitions nor reliable models to study their behavior. Despite our rapidly increasing knowledge, we are still lacking enough understanding of the feedbacks and mechanisms that trigger these transitions. Most available models either lack realism for predictive purposes, or are too complex and typically very uncertain. Alternatively, it has been recently proposed that one could measure the resilience of a system- and thus its proximity to a critical transition- using so-called generic early-warning signals. In my research, I am developing and applying such indicators in systems ranging from ecology to climate both theoretically and empirically.
Complex population dynamics and community resilience
Population models can lead up to complex dynamical behavior starting off from simple cycles to chaos. The interplay of such dynamics with seasonality, space, community, or population structure has been widely studied mostly for single or few species. These dynamics become even more complicated in multispecies communities. Nonetheless, their consequence for community stability and resilience are important to understand. I m interested in how environmental forcing, both in stochastic as well regular terms, affects these afore mentioned properties in multispecies communities. I am also investigating the role of ecological structure on these dynamics and in particular on the existence of alternative attractors and transitions among them that such complex dynamics may provoke.