A new study has analysed regional differences in biodiversity change, showing significant variations between different geographic areas.

The ‘Geography of biodiversity change in marine and terrestrial assemblages’ study, published in the Science journal, was led by researchers at the University of St Andrews; in partnership with several other leading institutions from across Europe and North America. The scientists aimed to map regional biodiversity change, drawing on data collated by the University of St Andrews’ biodiversity database.

The study’s lead researcher Dr Maria Dornelas, from the University of St Andrews’ School of Biology, said: “Our study shows biodiversity is changing everywhere, but we are not losing biodiversity everywhere. Some places are recovering and adapting. When biodiversity is in the news these days, it is often because the Amazon is on fire, or there is a global mass mortality event in coral reefs, and rightly so, because these are terrifying news. However, there is a lot of recovery also taking place silently in the background, and many places where not much is happening. Our study puts these things on the map and shows they are not contradictory. We knew that biodiversity is affected by many different human actions, with different timings and effects, but we didn’t have a clear understanding of what were the net effects of these actions across the planet.”

The scientists’ analysis of regional biodiversity change identified trends in biodiversity variations – comprising both species losses and gains– in order to determine differences in biodiversity loss between ecosystems. Marine habitats showed greater levels of overall change than land-based ecosystems; while biodiversity loss was shown to be more prevalent in tropical regions than elsewhere.

Sarah Supp of Denison University in Ohio, joint first author of the paper, said: “Biodiversity change is complex to understand because it can be measured in many different ways, including the number of unique species, and the identities of those species. Our study shows that while some locations have experienced decreases in the numbers of species, others show increases or little change at all. More consistently, however, the identities of species appear to be changing at nearly all sites – this kind of change is critical to planning conservation and management strategies, particularly for sites exhibiting rapid turnover.”

Joint first author Shane Blowes, from the German Centre for Integrative Biodiversity Research (iDiv), said: “Our study shows how biodiversity change varies geographically. The species that make up local assemblages are changing everywhere, but these changes are happening faster in marine compared to terrestrial assemblages.”