Stephen J. Gould once wrote that variation stands out as the only meaningful reality. Indeed, species persistence is not a fixed property, but a changing condition subject to ecological and environmental variations. This implies that it is necessary to systematically integrate community dynamics and environmental variations in order to increase our understanding about the conditions leading to species persistence. In this talk, I will introduce a structural framework based on the notion of structural stability as a direction towards this integration. I will illustrate the structural framework with the classic problem of coexistence among competing species. I will verify this framework with ecological and environmental data, and finally I will sketch out some ideas on how to use this framework to move back from understanding to prediction in ecology.