Individual trait variation is ubiquitous in nature and is central to populations involved in complex interactions with others in an ecological system. Such variation drives eco-evolutionary dynamics, shaping how populations and communities respond to environmental perturbation. In this talk, I will provide an overview of how individual variation can scale up to influence the stability, predictability, and resilience of populations to environmental perturbation, as well as the recovery dynamics of collapsed ecological communities. Furthermore, I will explore how individual trait variation, which is critical to species interactions within complex ecological networks, can dynamically evolve in response to changes in interaction strength, environmental perturbation, and network architecture. This consequently impacts how complex communities respond to changes in the environment. Lastly, the talk will highlight the importance of incorporating the adaptive nature of species interactions such as rewiring, eco-evolutionary feedbacks, and dynamic resilience frameworks to better understand the responses of complex communities to environmental change.