Is Biodiversity Declining Everywhere?

Apr 3, 2025

Maria Dornelas, a macroecologist at the University of St Andrews and the University of Lisbon, challenges the narrative of universal biodiversity decline. She reveals that local trends are mixed, highlighting the importance of nuance. Discussing the complexities of species turnover and the need for long-term data, she calls for a reevaluation of what constitutes 'good' and 'bad' biodiversity changes. Dornelas also emphasizes the critical role of effective communication in conservation and the necessity of understanding geographic and taxonomic biases in biodiversity data.

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INSIGHT

Biodiversity Trends Vary Locally

Local biodiversity trends are varied: some places gain species, some lose, and many stay stable.
Maria Dornelas found strong compositional change even when species counts remain similar.

INSIGHT

The Conservation Paradox Explained

The 'biodiversity conservation paradox' questions why widespread human impacts don't always produce universal local declines.
Dornelas frames this as an open scientific puzzle that invites deeper investigation.

INSIGHT

Composition Changes Drive Biodiversity Signals

Species identities change dramatically even when species counts don't, a process called compositional turnover.
Dornelas urges talking about 'biodiversity change' rather than only 'loss.'

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Guest: Maria Dornelas

In this episode of Inside Biodiversity, we look at one of the most controversial questions in biodiversity research: How ubiquitous is biodiversity loss? Our guest, Maria Dornelas, has challenged overly simplistic narratives of how biodiversity is changing. We discuss the current state of knowledge and how best to communicate it. Whether you are a sceptic or an advocate of biodiversity conservation, this conversation will give you new insights into the fascination and complexity of biodiversity change.

Maria Dornelas is a Professor at the University of St Andrews and the University of Lisbon, specializing in global biodiversity patterns, species diversity, and ecological change. Her research challenges common assumptions about biodiversity loss, using long-term data to reveal complex trends.

Links:

Maria Dornelas’s profile at the University of St Andrews: https://www.st-andrews.ac.uk/biology/people/maadd

Controversial paper discussed in this podcast episode: Assemblage Time Series Reveal Biodiversity Change but Not Systematic Loss https://www.science.org/doi/10.1126/science.1248484

Recent review paper: Looking Back on Biodiversity Change: Lessons for the Road Ahead https://royalsocietypublishing.org/doi/full/10.1098/rstb.2022.0199

Episode summary:

Maria Dornelas, a macroecologist at the University of St. Andrews and the University of Lisbon, challenges the common view that biodiversity is uniformly declining. Her research, based on the BioTIME database, reveals a more complex picture, with biodiversity trends varying by location—some areas remaining stable or even seeing increases in species diversity.

She discusses the "biodiversity conservation paradox," where human activities alter ecosystems, yet biodiversity declines are not universal. While biodiversity loss is real, it is part of a broader story that includes species turnover and recovery. Dornelas advocates shifting the focus from "biodiversity loss" to "biodiversity change."

Addressing criticisms, she acknowledges limitations like short analysis timeframes and regional biases in monitoring but emphasizes that her findings remain valuable. She calls for a more nuanced conservation approach, highlighting successes alongside challenges. Overly simplistic narratives, she warns, risk disengaging the public—echoing mistakes made in climate communication. Instead, she urges balanced messaging and expanded global biodiversity monitoring efforts.

Host: Volker Hahn Postproduction: Leven Wortmann