Organism-environment interactions in a changing world: a mechanistic approach

International audience

English. Understanding the interactions of an organism and its environment is essential for us to integrate ultimate and proximate causation on a global scale. Organism- environment interaction includes all organisms including animals, plants, and non-eukaryotes, etc. because all of them are responsive to environmental change including those that are human-induced.Amechanistic approach is important for us to understand why some organisms can cope with change and others cannot. Here, we present three examples of environments (''the three poles'') that are changing rapidly and how avian species typical of these ecosystems are responding. These examples include apparently adaptive responses to change in climate (i.e. the predictable environment) in one species in which a lengthened breeding season now allows multiple breeding attempts. Why other species are unable to respond in a similar way remains unclear. A second example describes how changing weather (i.e. the unpredictable) may have disastrous results for breeding success in a species adapted to an extreme cold environment. Implications for climate change in which weather extremes will become more common again suggest a mechanistic approach will be important to understand how organisms may respond. The third example outlines a scenario in which multiple human-induced rapid changes (a combination of predictable and unpredictable such as development, habitat change, introduction of invasive species and climate change) may influence indigenous species in different ways. Organism-environment interaction is a fundamental concept that may unify ultimate and proximate causation and point the way for future investigations striving to understand coping mechanisms in a world where both predictable and unpredictable components of the environment are changing