My research sits at the interface of demography and life-history theory, asking how environmental variation – in space and in time – shapes body size, life-history strategies, and population dynamics in wild populations. During my PhD, I used capture-mark-recapture data and structured population models to test how population growth responds to the timing and predictability of environmental conditions, using wild boar and mast-seeding systems. My postdoctoral work extended this focus on demographic performance to European and North American forests, before I turned to wild ungulate populations in mountain ecosystems, studying their response to changing land use and climate. I am now developing a new research programme extending this approach to a broader taxonomic and geographic scale, to understand why body size varies so widely within and between species, and to anticipate population vulnerability to climate change.