Frederik De Laender (Université de Namur)

The seminar will take place in person, Room S08, Faculty of Sciences

Title: Predicting the impact of environmental change on coexistence

I introduce a new approach to study effects of regional-scale environmental change on coexistence in ecological communities. The approach is based on the concept of feasibility, which measures how much one can change a model’s parameters while still maintaining positive species abundances.
I will first present analyses in small consumer-resource communities, and simulations results for larger communities. Together, these analyses and simulations support the conclusion that simple summary statistics of direct species responses suffice to predict effects on the size of the feasibility domain. However, our results also reveal that these effects critically depend on the interaction strength between consumers and resources.
I will then turn to food chains, confirming that simple summary statistics again predict environmental change effects on the size of the feasibility domain. In contrast to consumer-resource communities, however, these statistics do not scale up to larger food webs.
I finally analyse an extensive set of field data of macroinvertebrate counts across thousands of sites along less and more polluted small streams across the USA. These analyses suggest that communities in more polluted sites can coexist across narrower environmental ranges than communities in less polluted sites.