Biodiversity measures missing changes in marine ecosystems

Scientists may be missing key changes within marine ecosystems, as biodiversity measures fail to recognise reorganisation of ocean communities.

New research by the University of Adelaide has shown that current biodiversity calculations may be failing to detect species community changes due to ocean acidification.

The report found that in cases where biodiversity metrics show little to no change in marine ecosystems, species and habitat loss may still be occurring.

This leaves us without a clear picture of how the climate crisis are truly affecting the world’s oceans, but we know it can alter species abundance and diversity, feeding patterns, development and breeding, and relationships between other species.

‘The belief that climate change will alter global marine biodiversity is one of the most widely accepted,’ said Professor Ivan Nagelkerken from the Environment Institute and Southern Seas Ecology Laboratories. ‘Commonly used biodiversity measures don’t pick up reorganisation of marine communities due to ocean acidification because new species replace species that are lost.

‘Little or no biodiversity change is detected when one community of marine species is replaced by another even under significant habitat loss.’

Researchers investigated how species located around undersea volcanic CO2 vents and in laboratory mesocosms responded to climate changes, reviewing 81 studies in total.

They discovered experiments conducted in more natural environments were better at detecting biodiversity changes than those set up in laboratory conditions.

‘Experiments done in the laboratory are weak in detecting biodiversity change, so natural systems experiencing advanced ocean acidification are emerging as an innovative way of studying biodiversity responses,’ said the University of Adelaide’s Professor Sean Connell, who co-authored the study. ‘No ecological study, whether in the laboratory or field, can fully replicate the complex ecological interactions that exist in nature across the time and spatial scales of relevance to climate change.’

The scientists concluded future projections of ecosystem change will be more accurate if more studies focus on species replacement and changes to the abundance of species as signs of habitat loss.

Photo by Professor Ivan Nagelkerken, University of Adelaide