PDF Basket
There is much scientists do not know about how the plants and animals on islands coexist. However, they may be on the verge of a breakthrough. This is due to a better understanding of how island geology affects the species that live on islands, and how it shapes interactions among these species.
In particular, the new ‘general dynamic model’ links the evolution of island species to the geological life cycle of the islands themselves.
The EU-funded IDEA project aimed to investigate this model, both theoretically and by studying a group of birds known as Corvides. This group comprises around 800 species found all over the world, including well-known species such as crows, ravens and shrikes, and charismatic birds such as birds-of-paradise and vangas from Madagascar.
‘The project has great value in terms of basic science – islands are home to a disproportionate portion of the world’s rarest species, and more than 70 % of all extinctions of birds and mammals have occurred on islands,’ says project coordinator Michael Borregaard of the University of Copenhagen, Denmark. ‘It is therefore critical that we understand the factors controlling island diversity if we are to protect the remaining diversity.’
Geology and species diversity
The project team’s objectives included linking island geological history to diversity patterns, assessing the role of topography and vegetation on corvoid diversity patterns, describing the relationships between occurrences of plants and corvoid birds, and assessing how the traits of newly evolving species change over time on islands.
IDEA established databases of plant distributions, the geological composition of islands and topographic complexity. The researchers used this to reconstruct the biological and geographic history of corvoid birds and to describe how this relates to the geological history of the Malay Archipelago – one of the most biologically complex and rich groups of islands on the planet.
They gathered geographic and geological information on the archipelago and used the data to analyse the evolutionary relationships and distributions of birds.
Then they looked at the relationship between topography and vegetation on the one hand and corvoid bird diversity on the other. It is believed that more variety in the former two factors stimulates greater diversity because it is possible for the environment to sustain a greater population size.
Research was conducted in Udzungwa, Tanzania, a key area in the distribution of corvoid birds. This involved field observations of birds, vegetation and topography, using programmed camera drone flights and manual bird mist-netting – a method used to capture wild birds.
Putting corvoid birds on the map
‘The results indicate that there is a strong effect of geological history on diversity patterns. The project’s main scientific achievement was to move both the fields of corvoid evolution and geological island biogeography forward to a degree that has resounded internationally,’ says Borregaard.
The project has made the inclusion of the geological dynamics of islands essential to the study of species diversity on islands and has put corvoids on the international map as one of the most interesting groups in the study of island diversity.
The results will help the international research community understand patterns of species diversity, which is crucial for protecting biodiversity.
As part of the research, Borregaard underwent training in bird mist-netting and ringing. He obtained a certification in bird ringing – the process of attaching small metal or plastic rings to birds’ legs to enable researchers to identify them and reconstruct their movements over long distances.
Borregaard received training to become a certified drone pilot and in advanced field mapping techniques using drone imagery. He was trained in analysing phylogenetic trees, which are the diagrams that represent evolutionary relationships among individuals.
Five papers detailing the work were published in well- known scientific journals, while another six manuscripts have been submitted. The results have been disseminated in a radio interview, an interview on a major science blog and at several conferences.
IDEA received funding from the EU’s Marie Skłodowska-Curie fellowship programme.