Traditional knowledge about native plants has been transmitted across generations in Brazil's semi-arid Caatinga, shaping local strategies of survival, resilience, and cultural expression. This study explores the ecological and cultural significance of "macambiras" bromeliads of the genera Bromelia (e.g., B. laciniosa, B. arenaria) and Encholirium (e.g., E. spectabile), based on a combination of literature review and field interviews with rural communities. We document a wide range of ecosystem services associated with these species, including food and forage provision, medicinal uses, habitat structuring for biodiversity, and symbolic value in local traditions, literature, and material culture. Our findings reveal that knowledge about macambiras is maintained by older generations, reflecting a decline in traditional ecological knowledge due to urbanization and cultural shifts. We argue that macambiras fulfill the criteria of Cultural Keystone Species, as they play central roles in both ecological processes and the cultural identity of Caatinga communities. Moreover, we propose their use as model systems for studying plant species that integrate ecological functionality with biocultural resilience in other dryland regions. Recognizing and conserving these species is crucial for maintaining ecosystem services, cultural heritage, and social-ecological resilience in the Brazilian semi-arid zone.