Taxonomy and Conservation of Landbirds on the Aldabra Atoll - A CodonCode Aligner User Showcase


On the Aldabra Atoll, a UNESCO World Heritage Site in the Seychelles archipelago, CodonCode Aligner is used for phylogenetic studies of endemic landbirds. At the Seychelles Islands Foundation, Dr. Janske van de Crommenacker researches the taxonomic status of two local landbirds. She aims to find out whether they can be classified as separate species which would help to ensure their protection.


In addition Janske is investigating the influence from a related, invasive species that is possibly threatening the survival of Aldabra's endemic landbird populations.




Conserving Aldabra's Landbirds
by Dr. Janske van de Crommenacker

female and male European Corn Borer
Aldabra rail

My current project involves a phylogenetic research study of two of Aldabra's landbird species: the Aldabra fody and the Aldabra rail. The aim is to investigate their taxonomic status by checking whether they can be assigned as separate species rather than subspecies of the Comores fody and Madagascar rail. As the Aldabra populations of these two birds are very small, the taxonomic change would shift them upwards in the Red list of IUCN protected species, which would benefit ensuring their protection.


female and male European Corn Borer
Aldabra and Madagascar fody





Furthermore, a population of introduced Madagascar fodies has recently established on Aldabra. This species is a known invasive and, without action, the consequences for Aldabra's ecosystem could be severe: in addition to out-competing native birds, spreading novel pathogens and disrupting ecosystem processes, the introduced fodies could hybridize with endemic Aldabra fodies and potentially cause their extinction by the mixing of their genes. In the field we already have observed some potential hybrid birds that are difficult to identify either as Aldabra or Madagascar fodies. We have managed to catch them, and I am now analyzing their blood/DNA samples to assess whether hybridization has occurred and to what extent. The results will help identifying hybrids in the field during the eradication project, assessing the severity of the conservation crisis and increase support for the eradication project. More broadly, the threats of hybridisation with introduced species are not well understood and this project will provide important data on the effects of introduced species, which are not always possible to assess.

Larval ECB boring it’s way out of a plastic cup
Janske with an Aldabra rail

With CodonCode Aligner, Janske investigates the possible hybridization between endemic and invasive species like the fody. After collecting samples in the field, she builds consensus sequences for each individual bird. She will then align the contigs of multiple individuals to each other and create a phylogenetic tree showing the genetic distance from endemic Aldabra fodies, invasive Madagscar fodies, and hybrids.

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