A comprehensive global analysis has found alarming losses in the genetic diversity of plants and animals, with urgent action needed to address the issue. Spanning over three decades of research, the study published on January 31, 2025, in the scientific journal Nature, highlights significant declines across 628 species worldwide.
Conducted by an international team of more than 50 scientists, the study reveals staggering results: nearly two-thirds of the populations assessed are experiencing diminished genetic variance. While conservation efforts have seen success, particularly with some animal species, the data suggests there is no room for complacency. Rapid biodiversity loss is pushing many species closer to extinction, threatening their ability to adapt to environmental challenges.
"There is no denying biodiversity is declining rapidly across the globe – but there is also hope. Actions taken by conservationists can reverse these losses," stated Frank E. Zachos, head of the Mammal Collection at the Natural History Museum Vienna and one of the study’s authors.
The project, which analyzed genetic diversity data stretching from 1985 to 2019, employed advanced data analytic techniques to derive insights from diverse studies across all terrestrial and most marine domains. According to the findings, genetic diversity has been increasingly compromised, impacting species' resilience particularly among birds and mammals.
Professor Catherine Grueber, from the University of Sydney, emphasized the need for immediate conservation efforts: "Genetic diversity loss was observed across most terrestrial realms, whereas results across marine realms were more variable." The loss of genetic diversity diminishes species' ability to adapt to new threats such as diseases and climate change, making conservation strategies ever more urgent.
Much of the concern stems from the shrinking populations of species, which can lead to genetic bottlenecks. This diminishes the mix of genetic traits available within species and reduces their survival chances. Alarmingly, even species not currently considered endangered are exhibiting declines. "When a species has different genetic solutions, it's able to deal with changes," said David Nogués-Bravo, ecologist at the University of Copenhagen, highlighting how varied genetic traits can spell the difference between survival and extinction.
The current retrospective meta-analysis reviewed over 80,000 scientific articles, focusing on genetic changes across various populations globally and found significant declines across many species groups. This thorough examination allows researchers to identify effective conservation methods for sustaining genetic diversity.
The study articulated several key conservation strategies capable of bolstering genetic diversity. Notably, supplementation—adding individuals to existing populations—proved particularly effective, especially among birds. For example, initiatives aimed at safeguarding New Zealand’s South Island robins involved moving birds between isolated islands, leading to healthier populations with improved genetic health.
Population control, where excess individuals are removed, has shown varying results, but it can help maintain genetic diversity under certain conditions, as seen with the coaster brook trout hatcheries in the U.S.
Restoration of natural habitats, alongside population management, is another powerful tool. The greater prairie-chicken’s recovery efforts highlight how habitat restoration has coupled with the increase of genetic diversity. "Isolated populations suffer; the solution is to reconnect them," urged Stuart Pimm, Duke University ecologist. His point drives home the necessity of establishing connections between fragmented habitats to revitalize wildlife populations.
Successfully managing feral species is also tied to outcomes. Reducing invasive fox populations helped the Arctic fox recover by easing resource competition as new foxes were added, effectively enhancing the population’s genetic health.
Despite evidenced successes through conservation actions—particularly population supplementation—only half of the assessed populations benefited from any conservation management. The study underlines the urgent need for increased action to protect unmonitored populations.
Across the globe, the call for bolstering biodiversity has gained momentum as communities are encouraged to participate. Engaging with local conservation efforts, planting native species, and maintaining heirloom vegetables can collectively support genetic diversity.
Overall, this landmark study not only highlights the dire state of genetic diversity globally but also presents clear actions for reversing these trends. The emphasis on collaborative and informed conservation strategies presents hope for future biodiversity preservation. The resilience of species may depend on the actions taken today to reconnect, restore, and sustain genetic diversity.