Final Report Summary - BIRDEVOBIOGEO (PASSERINE BIRD EVOLUTION AND BIOGEOGRAPHY)
This project aimed at achieving an in-depth understanding of evolutionary and biogeographical patterns of one of the world’s most diverse and vulnerable island ecosystems focusing on core corvoid passerine birds (approximately 700 species). Core corvoid birds originated in Australia and New Guinea from where they dispersed by island hopping across the Indonesian archipelagos to Asia and onwards to other continents. However, there is also evidence for several trans-oceanic long-distance dispersal events directly from Australia to Africa. The Pacific has been colonized multiple times from Australasia and some members of these island clades have even back-colonized the Australian continent. Thus, current passerine distributions in the Indo-Pacific have been shaped in part by the complex geological history but also by complex evolutionary and ecological adaptations. Already available data combined with additional newly generated data during the two years the project lasted and by using state-of-the–art quantitative methodologies have facilitate research that would not have been possible in any other study system.
My research has integrated phylogenies with data on ecology and earth history to illuminate patterns of macroevolution and macroecology of passerine birds in the Indo-Pacific. Importantly, I have gone beyond pattern assessment to also test and compare the importance of factors that have been proposed to govern and determine species composition, community assembly, dispersal patterns and the build up of diversity within islands. As originally proposed I have done this by applying a range of evolutionary models and by explicitly testing classical island biogeography and island evolution hypotheses. In this respect Imperial College’s long and active tradition of considering a spectrum of theories that might be able to explain the diversity patterns, ranging from neutral theory to the 'meganiche' theory of adaptive zones has been of tremendous importance for the success of the project.
Building on previous work and ongoing collaborations, many new DNA sequences have been produced. This has resulted in the construction of a well-resolved robust phylogeny of the basal lineages of the core Corvoidea and also in a near complete species level supermatrix-supertree including 670 out of 780 (>85%) species of core corvoid passerine birds.
A number of phylogeographic studies on widespread Indo-Pacific species (e.g. Pitta erythrogaster, Pachycephala whistlers and Myiagra monarch-flycatchers) have shed new important light over island biogeography and the build-up of diversity in island systems, which is more complex than previously anticipated. These studies show that the build-up of island faunas are shaped by regular movement/dispersal of species as well as by interactions of closely related species and by the tectonic history of the focal region.
Using the passerine faunas of the Afrotropics and the Oriental I have shown that the build-up of continental passerine bird communities are continuously influenced by random extinctions of entire clades. This is a major finding, which reconciles a number of previously conflicting notions.
Furthermore, using data on morphology for all passerine birds (>5000 species) and a dated phylogeny I have analysed how morphological space is occupied through space and time. The morphological space occupied by passerine birds is a proxy for what passerine birds eat and what habitat they live in. I have shown that different groups of passerine birds generally occupy the same morphological space. Also, I have shown that speciation success appears not to be influenced by the order in which a group colonises a region relative to other closely related groups. This means that all passerine birds occupy a broad range of niches and potentially interact and that this has little to do with the relative order of colonisation.
Other significant results include how migration affects diversification across all birds. This study suggests that the evolution of seasonal migration in birds has facilitated diversification through the divergence of migratory subpopulations that become sedentary, and further illustrates asymmetrical diversification as a mechanism by which diversification rates are decoupled from species richness.
Finally, I have been involved in some other side projects, most notably the generation of the first whole genome phylogeny for birds, an attempt to reconcile hierarchical taxonomy with molecular phylogenies and the discovery of dramatic niche shifts of some passerine birds.
Overall, my project has progressed beyond expectations. The project has generated valuable new knowledge pertaining to our understanding of how communities form and what spatio-temporal factors determine the build-up of both continental and insular avian communities. I have published 11 research papers in journals including Science, PNAS, Systematic Biology and Proceedings of the Royal Society London Series b. I have also presented my work at leading universities (Oxford, Glasgow and Queens University) as well as at conferences (IOC in Japan and Biogeography Society meeting in Florida, USA). Now that the project period is over I can look back at two very fruitful years at Imperial College. I have published a series of significant contributions and I have achieved the goals that I initially set out as well as some additional side projects. Although, some publications are still to come, I have been engaged in work covering all aspects of my objectives.
My research has integrated phylogenies with data on ecology and earth history to illuminate patterns of macroevolution and macroecology of passerine birds in the Indo-Pacific. Importantly, I have gone beyond pattern assessment to also test and compare the importance of factors that have been proposed to govern and determine species composition, community assembly, dispersal patterns and the build up of diversity within islands. As originally proposed I have done this by applying a range of evolutionary models and by explicitly testing classical island biogeography and island evolution hypotheses. In this respect Imperial College’s long and active tradition of considering a spectrum of theories that might be able to explain the diversity patterns, ranging from neutral theory to the 'meganiche' theory of adaptive zones has been of tremendous importance for the success of the project.
Building on previous work and ongoing collaborations, many new DNA sequences have been produced. This has resulted in the construction of a well-resolved robust phylogeny of the basal lineages of the core Corvoidea and also in a near complete species level supermatrix-supertree including 670 out of 780 (>85%) species of core corvoid passerine birds.
A number of phylogeographic studies on widespread Indo-Pacific species (e.g. Pitta erythrogaster, Pachycephala whistlers and Myiagra monarch-flycatchers) have shed new important light over island biogeography and the build-up of diversity in island systems, which is more complex than previously anticipated. These studies show that the build-up of island faunas are shaped by regular movement/dispersal of species as well as by interactions of closely related species and by the tectonic history of the focal region.
Using the passerine faunas of the Afrotropics and the Oriental I have shown that the build-up of continental passerine bird communities are continuously influenced by random extinctions of entire clades. This is a major finding, which reconciles a number of previously conflicting notions.
Furthermore, using data on morphology for all passerine birds (>5000 species) and a dated phylogeny I have analysed how morphological space is occupied through space and time. The morphological space occupied by passerine birds is a proxy for what passerine birds eat and what habitat they live in. I have shown that different groups of passerine birds generally occupy the same morphological space. Also, I have shown that speciation success appears not to be influenced by the order in which a group colonises a region relative to other closely related groups. This means that all passerine birds occupy a broad range of niches and potentially interact and that this has little to do with the relative order of colonisation.
Other significant results include how migration affects diversification across all birds. This study suggests that the evolution of seasonal migration in birds has facilitated diversification through the divergence of migratory subpopulations that become sedentary, and further illustrates asymmetrical diversification as a mechanism by which diversification rates are decoupled from species richness.
Finally, I have been involved in some other side projects, most notably the generation of the first whole genome phylogeny for birds, an attempt to reconcile hierarchical taxonomy with molecular phylogenies and the discovery of dramatic niche shifts of some passerine birds.
Overall, my project has progressed beyond expectations. The project has generated valuable new knowledge pertaining to our understanding of how communities form and what spatio-temporal factors determine the build-up of both continental and insular avian communities. I have published 11 research papers in journals including Science, PNAS, Systematic Biology and Proceedings of the Royal Society London Series b. I have also presented my work at leading universities (Oxford, Glasgow and Queens University) as well as at conferences (IOC in Japan and Biogeography Society meeting in Florida, USA). Now that the project period is over I can look back at two very fruitful years at Imperial College. I have published a series of significant contributions and I have achieved the goals that I initially set out as well as some additional side projects. Although, some publications are still to come, I have been engaged in work covering all aspects of my objectives.