Fish zeta diversity responses to human pressures and cumulative effects across a freshwater basin

Aim: Declining biodiversity across ecosystems and myriad human pressures necessitate high-level regional assessments for effective management. Evaluation of biodiversity patterns and stressor accumulation through beta diversity and cumulative effect analyses are two key methods for management prioritization. This study links these concepts to develop a novel cumulative effect metric based on beta diversity responses.
Location: Fraser River basin, British Columbia, Canada.
Methods: Multi-Site Generalized Dissimilarity Models were used to evaluate non-linear relationships between fish species compositional differences (ζn, number of shared species across any number of watersheds compared) and human pressure, environmental, and geospatial differences among all watersheds and within low, mid-, and high elevation clusters. A cumulative effect metric was calculated as the sum of response values generated by the model for each human pressure variable specific to each watershed, when evaluated...