Biological surrogacy in tropical seabed assemblages fails

Area of Science:

• Marine ecology
• Biodiversity assessment
• Conservation science

Background:

• Marine biodiversity surveys are resource-intensive, necessitating the use of surrogate taxa.
• Understanding the effectiveness of different taxa as surrogates for others is limited by data availability.

Purpose of the Study:

• To investigate the performance of taxonomic groups as surrogates for marine biodiversity patterns.
• To assess the impact of taxonomic resolution, rare species removal, and clustering on surrogate effectiveness.

Main Methods:

• Utilized a comprehensive dataset of 11 phyla across 1189 Great Barrier Reef seabed sites.
• Grouped sites into assemblages using Hellinger distances and medoid clustering for each taxonomic group.
• Quantified surrogate performance by measuring the concordance of assemblages between taxonomic pairs.

Main Results:

• Surrogate performance improved when taxa were grouped at the phylum level compared to finer resolutions.
• Excluding rare species did not significantly affect surrogate performance.
• Decreasing the number of clusters used to define assemblages increased mean surrogate performance.

Conclusions:

• No single taxonomic group effectively surrogates for others in mapping seabed biodiversity.
• Sampling multiple taxonomic groups is essential for robust understanding of tropical/subtropical seabed communities.
• Excluding rare species may allow for broader taxonomic sampling under resource constraints.