RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: This study sought to understand the role of plants and animals in traditional medical systems and evaluate the capacity of these systems to absorb impacts and maintain their identity by determining the existence of functional substitutes. MATERIAL AND METHODS: Ethnobiological data were collected through semi-structured interviews and free lists at a rural community in the semiarid region of northeastern Brazil. The data were subjected to the utilitarian redundancy model and analyzed by tests of proportion and variance. RESULTS: We found that most of the therapeutic targets treated with animal-based remedies were also treatable by plant-based remedies; these targets were perceived as very usual, although they were not considered dangerous. Furthermore, people considered the plants and animals to be equally effective at curing overlapping therapeutic targets, but the plant remedies were used more frequently. The findings show that local knowledge about medicinal plants and animals follows similar patterns regarding the utilitarian redundancy, with high functional overlap among these features. However, the ease of access to the medicinal resource influences the choice of treatment, leading to an increased preference for plants over animals. In addition, we suggest that during the cultural evolution process, people concentrated their efforts on experimenting with different resources for the treatment of diseases that were very frequent locally, even if not very severe, which contributed to the resilience of the local medical system. CONCLUSION: Furthermore, we infer that plants may effectively perform the function of healing, whereas animals act as reserves of resilience for the system, maintaining system function in the face of disturbances that may affect the availability of plant species.