Thesis defence by Michiel LATHOUWERS

Title: Assessing the effects of global change on avian migratory pathways: the case of the European Nightjar

In a world becoming progressively human dominated, understanding the impacts on migratory birds is becoming increasingly important. The variable environments they depend on throughout their annual cycle leave them uniquely vulnerable to effects of global change, which has resulted in drastic and persistent declines. I made use of modern techniques like wildlife tracking and remote sensing of the environment to document the extraordinary migratory journey of the European Nightjar in unprecedented detail, in order to elucidate key aspects of their behaviour and ecology during under-studied parts of their annual cycle. I have shown how the European Nightjar adopts flexible time-allocation strategies in response to environmental conditions encountered en route. Nightjars exploit food resources in an opportunistic way during active travel segments of their migration, possibly limiting the time they need to spend on stopovers and relieving them from time constraint in their annual cycle. Additionally, when Nightjars select a stopover site, they tend to favor areas with diverse land cover types, distributed in the landscape in a non-aggregated way. This likely allows them to quickly allocate food resources and avoid spending time looking for the most optimal feeding habitat. These demonstrations of flexible behaviors likely serve to buffer adverse impacts of unforeseen negative conditions resulting from global change, while still adhering to a strict spatiotemporal migration schedule and limiting fitness costs. Future socio-economic developments and emission scenarios will inevitably lead to large-scale losses of suitable habitat for a long-distance migrant such as the European Nightjar. Forward-looking spatial planning for conservation, prioritizing refugia, future habitat, corridors for connectivity, and maintenance of landscape heterogeneity, will play a crucial role in protecting ecological options and enabling the persistence of long-distance migrants in the shifting and unpredictable Anthropocene.

Michiel will present the results of his PhD thesis, conducted at the University of Hasselt under the supervision of Tom ARTOIS and Nicolas DENDONCKER (Geography, ILEE).