Despite the global biodiversity crisis, some ecosystems are showing encouraging signs of recovery, especially in Europe and North America. We do not have a clear understanding of how ecosystems recover from degraded states, of the causes and consequences of such recovery, or of how emerging species interactions affect and are affected by ecological processes. In this thesis, I investigate the patterns and processes emerging from recovering ecosystems by analysing population dynamics, species interactions and animal movement.
I explore the spatiotemporal trends of an expanding large mammal community in the Alps and investigate predator-prey interactions between wolves and their main prey. I assess the permeability of the Alpine landscape for recovering populations, by analysing the impact of natural and anthropogenic factors on the movement of a partially migratory ungulate. Studying species interactions in a dynamic and recovering system such as the Alps is challenging. I therefore focus on the Yellowstone ecosystem to analyse the impact of wolf predation on their prey and on other ecological processes. I develop a mechanistic, bio-energetic model of the vegetation-elk-wolf system, to study how energy acquired through resources flows across trophic levels influencing population dynamics and interactions. I then use this model to study how ecological and evolutionary change can affect complex tri-trophic systems.
I show that large mammal communities can recover relatively quickly in the right environment, and with the support of conservation and favourable environmental legislation. Nonetheless, humans can still have a significant impact on animal populations by affecting their movement patterns and habitat use. In the Alps, I could not detect an impact of wolf predation on prey populations because the recovery process is still ongoing and the system is highly dynamic. In Yellowstone, on the other hand, I show that wolf predation can have significant effects on the ecosystem, and that complex trophic interactions can respond in unexpected ways to ecological and evolutionary change.
My thesis offers advances for investigating complex terrestrial systems, for predicting the potential impacts of environmental change on ecosystems, and for informing future policy and landscape management decisions
