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Island Diversity from an Eco-evolutionary Approach

Periodic Reporting for period 1 - IDEA (Island Diversity from an Eco-evolutionary Approach)

Reporting period: 2016-03-15 to 2018-03-14

"Since the early days of natural history, oceanic islands have been a birthing ground for new theories and ideas. Islands are isolated, which means they have fewer species, but it also means they have many more locally evolved species that live nowhere else. Thus, islands are thought of as ""natural laboratories"" - testing grounds for new theory and ideas.

Still, there is so much we don't know about how the plants and animals on islands come together on islands and coexist. But a lot of research currently focuses on islands, and we now be on the verge of a breakthrough in terms of understanding island life. This breakthrough may happen because we are getting a better understanding of island geology, topography and the relationship among species. In particular, a new model, the ""General Dynamic Model"" links the life of island species together with the geological life cycle of the islands themselves.

The project aimed to investigate this model, both theoretically and by studying a group of birds called the Corvides. This group consists of ~800 bird species all over the world, with many well-known members, such as the crows, ravens and shrikes, and also very charismatic birds such as the birds-of-paradise and the vangas in Madagascar.

The project not only has great value in terms of basic science - islands contain a disproportionate portion of the world's rarest species, and more than 90% of all extinctions of birds and mammals have occurred on islands. It is critical that understand the factors controlling island diversity if we are to protect the remaining diversity.

The objectives of the study were:

1. To link the island geological history to diversity patterns
2. To assess the role of topographic and vegetation complexity on corvid diversity patterns.
3. To supplement the large-scale gradient with drone-based reconstructions of bird diversity along a mountain in Udzungwa, East Africa.
4. Map relationships between plants and corvid birds
5. Assess how traits evolve on islands
The results indicate that there is a strong effect of geological history on diversity patterns. During the project, I've worked on 5 papers that are already published and as many in preparation. This includes a review paper of how geology affects island diversity, and one on how the history of the Indo-Pacific has affected the evolutionary history of the corvides. The project also has lead to several analytical papers focusing on the evolutionary history and traits of the Corvides, as well as cross-taxon congruency.

The work done entailed establishing data sets on plant occurrences in the Indian Ocean and Pacific archipelagos, expanding an existing data base on Corvid birds, as well as developing novel analytical methods to understand how complex real islands are, and how important this is for biodiversity.

In addition to the dissemination in scientific journals, the results have been disseminated in a radio interview, a written interview on a major science blog, and at several scientific conferences.
The project has helped move the bar for what needs to be considered when working with patterns of island diversity. This has important impacts for conservation as well - it's becoming clear that islands play a clear and irreplaceable role in the evolution of Earth's diversity.

The project aimed at resolving a range of the most pressing general questions in current island biogeography, using a study system of broad interest. Original advances to the field include:
• Establishment of high-quality geographical dataabeses
• A pioneering effort to apply island theories that are developed for relatively simple island settings to one of the most complex and rich island settings on the planet
• A completely novel extension of the general dynamic model into considering trait space and its importance in shaping evolutionary opportunity
• Pioneering an analytical approach to studying cross-taxon interactions and their importance in community assembly.
An early draft for the main summary figure of the Science review