Protected and conserved areas (PCAs) target at biodiversity conservation and human well-being, but often reflect low levels of effectiveness. Understanding PCAs social-ecological systems in which people and nature interact in so-called social-ecological interactions is key to understanding the roots of (in)effectiveness, and to leverage change toward resilient and sustainable systems. Despite this potential, social-ecological interactions in PCAs are commonly neglected in effectiveness evaluations. To address this gap, we elaborated a thorough understanding of the social-ecological interactions in PCAs through the following steps: In a first step, we extracted from scientific literature which social-ecological interactions influence the effectiveness of PCAs in general and derived influencing factors which shape those interactions. Based on these insights, we developed an analytical framework, which, in a second step, we applied to a case study in North Luangwa, Zambia. We elucidated three dimensions of social-ecological interactions occurring in the study area: care (e.g., conservation programs), conflict (e.g., disease transmission), and use (e.g., hunting). We visualized relationships between these interactions and associated key variables in a causal loop diagram. Finally, we drew on the case study in Zambia's Luangwa Valley to propose system-specific metrics for key variables central to the social-ecological structure of the study area to make effectiveness measurable. Our approach allows for linking site-specific social-ecological interactions to PCA effectiveness. More generally, our findings call for the consideration of the relationships between people and nature when assessing conservation effectiveness.