Forest Degradation as a Potential Driver of Shifting Baseline Syndrome in Northeastern Brazil: A Case Study.

Human-induced environmental changes cause shifting baseline syndrome (SBS), where degraded conditions redefine 'normal', leading to generational differences in perception and ultimately influencing biodiversity conservation strategies. In this case study, we examine (1) whether forest degradation influences SBS through local ecological knowledge (LEK) of woody medicinal plants, and (2) whether the cultural transmission of LEK contributes to resilience against SBS, focusing on two communities in Pernambuco state, Brazil, with distinct characteristics: Sítio Cutia, a frequently used forested area with high degradation, and Sítio Limeirinha, a monitored forested area with lower degradation. We conducted semi-structured interviews with residents (18+) grouped by age groups. To assess the effects of forest degradation on SBS, we analyzed age group differences in knowledge of woody medicinal plant richness (using GLMs) and perceptions of plant availability (using PERMANOVA and nMDS). LEK transmission networks were examined to evaluate whether cultural transmission contributes to resilience against SBS (using interaction degree distribution under different extinction scenarios). Contrary to expectations, our study suggests forest degradation does not necessarily intensify SBS, as perceptions of ecological change remained relatively stable across age groups. Within the monitored forest site, LEK transmission networks showed higher potential for resilience, indicating that intact ecological processes can help maintain accurate environmental knowledge over time. While the findings are specific to the socio-ecological systems examined, they highlight the value of integrating biodiversity conservation with cultural knowledge transmission. Efforts to mitigate SBS should integrate ecosystem conservation and age-structured LEK maintenance.