A new freshwater biodiversity indicator based on fish community assemblages

Area of Science:

• Ecology
• Conservation Biology
• Ichthyology

Background:

• Biodiversity is declining globally, necessitating effective indicators for monitoring and communication.
• Existing biodiversity indicators often lack a synthetic view or fail to capture ecosystem processes.
• Riverine fish communities serve as a model to develop and test new biodiversity assessment tools.

Purpose of the Study:

• To develop and validate novel community indicators for biodiversity assessment.
• To integrate species specialization and originality concepts into biodiversity metrics.
• To evaluate the sensitivity of these indicators to land use change and human pressures.

Main Methods:

• Developed species-level specialization and originality indices based on niche theory.
• Analyzed five types of originality indices: phylogenetic, morphological (diet/habitat), life history, and ecological niche.
• Assessed temporal trends and spatial patterns of indices using fish community data.
• Correlated biodiversity indices with land use data as a proxy for human impact.

Main Results:

• Most biodiversity indices showed no significant temporal trends.
• Originality indices based on diet and habitat morphology increased significantly over time.
• Corsica Island exhibited higher average originality and specialization compared to other areas.
• The originality index based on ecological niche traits proved sensitive to land use gradients and consistent across scales.

Conclusions:

• Novel biodiversity indicators integrating specialization and originality show promise for ecological assessment.
• The ecological niche-based originality index is a robust indicator of biodiversity status under land use change.
• These findings support the use of advanced community metrics for effective biodiversity monitoring and conservation communication.