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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - BAYESLAND (Community Assembly on Islands: A phylogenetic Bayesian approach)

Teaser

Summary

BAYESLAND aimed to bring new knowledge about what drives migration of species among islands, in particular in the Canary archipelago. Sequencing the DNA of a group of species allows determining the evolutionary relationships of these species, that is best described by a phylogenetic tree whose branches represent lineages diversifying with time into a variety of species. The phylogeny, coupled with the knowledge of the current geographic distribution of species, allows getting insights into the processes driving species to migrate between islands, across the ocean.
Scientists use mathematical models to try and retrace the movements of species in the past (biogeographic models). Biogeographic models estimate the most likely scenarios of past migration, including the number and type of migration events that may have occurred. Such inferences differ a lot among the taxa considered. BAYESLAND aimed to develop some of the currently existing biogeographic models to include new types of data, so as to understand better what determines migration patterns. In particular, the models developed in BAYESLAND should help understand why some species migrate more than others, estimate the importance of migration between populations of the same species, what is the relative importance of geographic versus ecological factors in determining the frequency of migration events.
Understanding past migration patterns and processes is important to understand the plasticity of current ecosystems. Within which geographic perimeter do species move so much that they form genetically homogenous populations? How rapidly can species shift their geographic distribution to respond to human disturbance or climate change?

Work performed

BAYESLAND provided extended biogeographical models, notably including DNA data of various individuals/populations of the same species, yielding estimates of migration events that do not end up in the formation of new species, or making a link between migration rates and some explanatory variables such as geographical (e.g. the distance between islands, topography, island areasâ€¦) or ecological predictors (e.g. taxonomy, modes of movement, modes of reproductionâ€¦). BAYESLAND further allowed to critically assess some existing models, and in particular identified potentially serious problems concerning some models of the evolution of species traits with selection, or models of intra-specific migration.
The results of BAYESLAND are to be disseminated to the scientific community through a series of articles in scientific journals, and through oral presentations and posters at international conferences. Furthermore, BAYESLAND will also serve to summarize existing knowledge in phylogenetic modelling, through the publication of a paper reviewing the broad diversity of phylogenetic models.

Final results

The research carried out in BAYESLAND has produced important outputs. The articles to be published will provide important new knowledge for the scientific community. The new models developed will help scientists answer more precise questions about the determinants of migration, helping theorize the appearance of biodiversity, and helping understand its current distribution across the geographic template.