Summary
Highlights
When species habitats shrink, populations decline, leading to inbreeding among relatives. This inbreeding depression reduces survival and fertility, causing populations to shrink further and risk extinction. Genetic rescue is an effective solution that introduces new genetic diversity, repairing inbreeding and helping populations adapt to stressors like climate change. It encourages mating between individuals from different populations or even subspecies when a population is the last of its kind.
Sasha Pavlova and Paul Sunnucks at Monash University conduct research to increase genetic diversity in small populations, helping them rebound. They have developed methods to save endangered species from genetic problems, collaborating with conservation managers, Australian wildlife agencies, and international groups to test solutions for various endangered species.
The helmeted honeyeater, once common in Victoria, is now restricted to a single reserve due to habitat loss. Research revealed severe inbreeding depression, with the most inbred individuals having only 10% the reproductive output of the least inbred. To combat this, Zoo Victoria collaborators crossed helmeted honeyeaters with another yellow-tufted honeyeater subspecies. These cross-bred birds are thriving, and a second population was established in 2021.
The Macquarie perch, an Australian freshwater fish, faced immense stressors like overfishing and habitat degradation, leading to small, isolated populations. Pavlova's work suggested that genetic problems could be assessed through simpler genetic analyses and predicted benefit of rescue through computer simulations, rather than needing to prove inbreeding depression for each population specifically. Her findings influenced the national recovery plan, where reintroducing Macquarie perch from multiple sources into the Ovens River resulted in better survival and reproduction compared to a single-source approach.
Genetic rescue is also applicable to plants. The button wrinklewort, a daisy that lost over 99% of its habitat, was subject to a collaborative effort to evaluate genetic diversity. Surprisingly, some of the smallest, most isolated populations exhibited the highest diversity, indicating that larger populations don't always equate to better genetic health. This shows the importance of detailed genetic assessment.
Genetic rescue is gaining acceptance and uptake. Over the past three decades, scientists like Pavlova and Sunnucks have successfully integrated genetic research with conservation efforts. Australia has emerged as a leader in using genetic rescue for conservation planning. Sunnucks emphasizes the urgency of global adoption, warning that without genetic rescue, many small, isolated populations will simply be managed towards extinction.