Birds and mammals that live on islands often have a much slower metabolism than their closest relatives on the mainland. They also produce offspring later. This slow way of life makes it difficult for them to adapt to rapid changes, such as those caused by humans. This was the finding of a new study led by an international team from Martin Luther University Halle-Wittenberg (MLU), the Chinese Academy of Sciences, and Sichuan Agricultural University. The team analysed data from around 2,800 animal species living on islands and the mainland. The results were published in the journal " Science Advances".
Islands are unique habitats on account of their geographic location. "Animals that live on islands have a limited food supply, but also fewer predators and competitors. They adapt to these special conditions in order to maximise their success at survival and reproduction. This leads to unique evolutionary adaptations," explains Dr Roberto Rozzi, a palaeontologist from MLU. For example, island-dwelling animals can be significantly larger or smaller than their mainland counterparts. This phenomenon is known as island dwarfism or gigantism. "In addition to these and other morphological changes, insular vertebrates can also display changes in their behaviour and metabolism," adds 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. This included 2,118 warm-blooded species, like birds and mammals, and 695 cold-blooded species, such as reptiles and amphibians. The study found that birds and mammals that live on islands tend to have a slower metabolism and produce offspring later. "This adaptation helps them to thrive in pristine island environments. However, it also makes these animals particularly vulnerable after human colonisation. Dwarfism and gigantism make island dwellers easier targets and more prone to being hunted by non-native predators, including humans. At the same time, a slower pace of life makes it harder for them to bounce back after environmental disturbances such as the introduction of invasive species or habitat loss," summarises Rozzi.
The results of the study provide important information which can contribute to identifying particularly vulnerable species on islands and enabling effective conservation. "In order to better protect the remaining island species, conservation efforts would benefit from taking into account the unique morphological and physiological differences between these animals and their mainland counterparts," concludes Rozzi.
The study was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) as well as the Scientific Research Foundation and National Natural Science Foundation in China.
Study: Ying Xiong et al. Convergent evolution toward a slow pace of life predisposes insular endotherms to anthropogenic extinctions. Science Advances (2024). doi: 10.1126/sciadv.adm8240
Science Advances
Data/statistical analysis
Not applicable
Convergent evolution toward a slow pace of life predisposes insular endotherms to anthropogenic extinctions
12-Jul-2024
The authors declare that they have no competing interests.