Researchers from Flinders University's Molecular Ecology Laboratory analyzed thousands of DNA markers from 467 southern pygmy perch collected at 30 sites across Australia's Murray–Darling Basin. The study, published in the Journal of Heredity, combined this genomic data with climate modeling to assess future vulnerability across the species' remaining range.
The endangered freshwater fish has declined sharply due to habitat loss, river regulation and prolonged droughts, leaving small, isolated populations with limited genetic diversity. The analysis revealed that populations in upland streams are generally more vulnerable to future climate change than those in lowland wetlands and rivers.
Elevation alone emerged as a strong predictor of vulnerability, suggesting conservation managers could use this simple landscape feature to flag high-risk populations in other freshwater systems without needing detailed genomic data for every case.
The team also evaluated a captive breeding and reintroduction program launched after the species disappeared from the Lower Lakes region during the Millennium Drought. The restored population retained its capacity to adapt to future warming, providing rare empirical evidence that genomics-informed breeding can preserve long-term evolutionary resilience.
Lead author Dr. Emily Booth said the research demonstrates how genomics can help managers prioritize actions where they will have the greatest impact. Senior author Professor Luciano Beheregaray added that the field has moved beyond describing biodiversity to actively informing conservation decisions such as assisted gene flow and habitat restoration.
Freshwater fishes are among the world's most threatened vertebrates yet receive comparatively little conservation attention. The researchers say the framework developed for the southern pygmy perch can be applied to other freshwater ecosystems facing rapid environmental change.
The study acknowledges that genomic vulnerability assessments are one component of conservation planning and that habitat quality, connectivity and non-climate threats also determine population persistence. Further work is needed to test the elevation-based proxy in other species and regions.
Genomics used to find endangered fish populations most vulnerable to climate change
This is an independent summary. The complete reporting, supporting context and any primary documents remain with Phys.org.