Human expansion and climate change, by contributing to rapid changes in many ecological processes, can have dramatic consequences on wildlife. This is especially true for Arctic migratory species, where a mismatch between resource availability and migration arrival date in the breeding range can have cascading effects that reduce reproductive success, causing populations decline. In North America, the migratory tundra ecotype of caribou, the barren-ground caribou (Rangifer tarandus groenlandicus), has experienced precipitous declines in several populations across its range. Given the importance of the species for couple human-ecological systems in the Arctic, population declines are a real and present concern, and there is a specific need to analyse the mechanistic environmental drivers of caribou population dynamics to better understand the causes of the declines. The objective of this project is to understand the rapid declines in caribou populations, with a particular focus on the direct and indirect effect of climate and human developments. During this postdoctoral opportunity, I will synthesize very large-scale movement data from >1000 females caribou across North America with environmental, demographic, and physiological data. To disentangle the direct and cascading effects of climate change and human development on demographic and physiological traits of barren-ground caribou, I will use Structural Equation Modelling (SEM). This study would provide essential insights into the impact of climate and human-induced change on this keystone herbivore, and results could be used for conservation actions, to propose alternatives for mitigating these effects.