Featured Science Paper
Climate change selects for heterozygosity in a declining fur seal population
Genetic analysis of Antarctic fur seals, alongside decades of in-depth monitoring, has provided unique insights into the effect of climate change on a population of top-predators. These findings show that the seals have significantly altered in accordance with changes in food availability that are associated with climate conditions. Despite a shift in the population towards ‘fitter’ individuals, this fitness is not passing down through generations, leaving the population in decline.
Environmental change is expected to affect many species and biological systems throughout the world. To understand these changes, long-term monitoring is required. BAS’s unique Long Term Monitoring and Survey programme has given researchers a rare opportunity to explore how fur seal life histories have changed over time in relation to the climate and food availability.
Researchers from the BAS and Bielefeld University in Germany analysed data gathered from as far back as 1981 to assess changes over generations of female fur seals on South Georgia, in the South Atlantic Ocean.
The researchers found that females who did survive to motherhood were likely to be more ‘heterozygous’. This is where an individual possesses a higher level of genetic variation and is associated with higher fitness in many species. Whilst these females are more likely to survive and breed, their pups will only have the same advantage if they too are heterozygous. However, the heterozygous characteristic is not inherited; it depends on which male the female mates with and so arises mostly through chance. This means that many seals are born who are not heterozygous and are therefore less able to cope with the changing environment.
Climate change is already altering environmental pressures on many species, and scientists do not yet know how populations will cope with these new environments. This study shows that natural selection on a fur seal population has altered as a result of climate change and that the seals have been unable to evolve in response.
Link to the full paper in the NERC Open Research Archive
Authors
Forcada, Jaume; Hoffman, Joseph Ivan. 2014
Publication
Nature, 511 (7510). 462-465 10.1038/nature13542
