The Drifting Baseline Syndrome: A Novel Concept of Perceived Biodiversity Change

The ongoing biodiversity crisis, driven by human activities, threatens ecosystems and public health. Understanding how different demographic groups perceive biodiversity change is key to effective conservation strategies. We conducted a cross-sectional survey of German-speaking participants (n = 899, 62.2% female) to assess biodiversity perception. Respondents reported declines in familiar species like fish and birds, but perceived microbial diversity as increasing. As for age-related differences, younger participants were generally less likely to recognize biodiversity change. However, this pattern did not hold uniformly across all age groups. No significant gender differences were observed. The well-established concept of shifting baseline syndrome shows how each generation tends to underestimate long-term ecological change. Our findings suggest a more complex pattern. We introduce the novel idea of a drifting baseline syndrome, in which biodiversity perceptions shift both downward and upward over time. This dynamic process goes beyond generational change alone. By bridging the gap between long-term and short-term perception shifts, the concept helps to deepen our understanding of how environmental change is perceived and remembered. Intergenerational dialogue and education can help address drifting baselines. These approaches may bridge perception gaps, encourage sustainable behaviors, and strengthen conservation efforts, ultimately benefiting both ecosystems and human well-being.