Multi-scale effects of pulsed-resources on consumers in temperate oak forests – PURE

In the current context of global changes, better understanding the ability of species to cope with increasing environmental variation is of great interest. This project aims to assess how seed consumers can buffer fluctuating pulsed food resources (acorn production) in temperate oak forests, at multiple levels of biological organization: from trait, to population and community. At the trait level, phenotypic plasticity and homeostasis are two kind of adaptations to fluctuating environments. The first objective is to assess whether milk composition, a key trait in mammals determining offspring demographic performances and their vital rates later in life, can be buffered against variation in acorn production by homeostasis. This will be tested in an omnivorous seed consumer species expected to mitigate the absence of seeds in some years by shifting its diet, the wild boar. At the population level, demographic lability and demographic buffering are two kind of adaptations to fluctuating environments. Lability allows species to take advantage of favorable years to increase their vital rates (e.g. reproduction) whereas buffering allows species to exhibit constant vital rates independently of environmental conditions. The second objective is to assess empirically the cascading effects of acorn production on the vital rates of populations within a community, and to examine whether some are buffered against variation in seed production. This objective will rely on a unique dataset bringing together individual long-term monitoring (>10 years) of multiple interacting species in a temperate oak forest. The third objective is to determine how effects of acorn production on multiple interacting species scale up at the community level. In particular, this objective aims to determine if and when, under realistic mechanistic scenarios of acorn production in a warming world, there will be a shift (increase or collapse) in population and community dynamics of seed consumers.