Birds and mammels on islands have a slower metabolism than their closest relatives on the mainland
Based on a media release of Martin Luther University Halle-Wittenberg (MLU)
When birds and mammals live on islands, they also have offspring later. This slow way of life makes it difficult for them to adapt to rapid changes such as those caused by humans. This is the finding of a new study led by an international team from the German Centre for integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig and Martin Luther University Halle-Wittenberg (MLU), the Chinese Academy of Sciences and Sichuan Agricultural University. For the study, the team analysed data from around 2,800 animal species on islands and the mainland. The results were published in the journal Science Advances.
Islands are unique habitats due to their geographic location: "On islands, animals find a limited food supply, but also less predators as well as competitors. They adapt to these peculiar conditions in order to maximize their success at surviving and reproducing. This leads to unique evolutionary adaptations," says palaeontologist Dr Roberto Rozzi from MLU and alumnus from iDiv. For example, animals that are significantly larger or smaller than their mainland counterparts can be found on islands. These phenomena are known as island dwarfism or gigantism. "Along these and other morphological changes, insular vertebrates can also show changes in life history and metabolism," continues Rozzi.
According to Rozzi, little was previously known about the differences in metabolism between island and mainland dwellers. The team therefore analysed data, including metabolic data, from 2,813 vertebrate species: these included 2,118 species with the same temperature, including birds and mammals, and 695 species with alternating temperatures, such as reptiles and amphibians. According to the study, birds and mammals on islands tend to have a slower metabolism and have offspring later. "This adaptation helps them to thrive in pristine island environments. However, it also makes these animals particularly vulnerable after human colonization. While dwarfism and gigantism predispose island biotas to direct hunting and predation by introduced species, a slower pace of life makes it harder for them to bounce back after environmental disturbances such as invasive species or lost habitats," summarises Rozzi.
The results of the study provide important information for effective species conservation on islands: particularly vulnerable species can be identified. "To better protect the remaining island species conservation prioritization should also take into account their unique morphological and physiological differences from their mainland counterparts," concludes Rozzi.
The study was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) and the Scientific Research Foundation as well as the Nature Science Foundation in China.
Original publication
(Researchers with iDiv affiliation and alumni bolded)
Xiong, Y., Rozzi, R., Zhang, Y., Fan, L., Zhao, J., Li, D., ... & Lei, F. (2024). Convergent evolution toward a slow pace of life predisposes insular endotherms to anthropogenic extinctions. Science Advances. DOI: 10.1126/sciadv.adm8240
