Biodiversity and extinction risk
One of the core areas of my research is evaluating how biodiversity shapes ecosystem properties, and the impacts of assembly history on this relationship. We have found that for the birds of the the Solomon Archipelago assemblage vulnerability - an ecosystem property - is positively related to diversity, and that this relationship is contingent on biogeographic history. While some aspects of assembly that may be ecologically important may appear random, they assume a degree of predictability when viewed through a phylogenetic lens. This raises an exciting prospect: if community assembly history impacts ecology in a deterministic way, an historical approach to reconstructing assembly may allow for predictions to be made broadly about contemporary ecology. As a first step toward this, we have developed a framework for disentangling the roles of ecology and evolution in guiding community assembly. I am in the process of applying this framework to mixed-species foraging flocks of birds in the Solomon Islands. There are myriad opportunities to expand this work, including global scale analyses of vulnerability and more focused experimental tests of historical imprints on biotic interactions within the Solomons.
Biotic Responses to Global Change
For several years, I have been working with an extraordinary specimen series of migratory species, collected for the past 40-years in Chicago. We find consistent morphological responses to increasing temperatures across a wide range of species. Warmer temperatures are driving size reductions, and at the same time wing length is increasing. We have since integrated timing of migration, finding that species are migrating earlier, but that this advance in migration does not seem to be driving increases in wing length that are occurring at the same time...which is...weird! We are continuing to try to understand what is driving the observed increases in wing length observed in almost all of these species.
Dispersal and Diversification
Different models of speciation predict contrasting patterns in the relationship between the dispersal ability of lineages and their diversification rates. This relationship is expected to be negative in isolation-limited models and positive in founder-event models. Contrary to expectations based on theory, for birds that diversified across Australasian archipelagoes, dispersal has inhibited diversification (Weeks and Claramunt, 2014). I am in the process of expanding this work to look at the relationship between dispersal and diversification at a global scale, connecting morphological proxies for dispersal ability with genetic evidence of divergence, and contrasting this relationship for paired groups that diversified on continents and islands.
Mixed-species Foraging Flocks in the Solomon Islands
Mixed-species foraging flocks have been documented on every continent in the world, and while they are present in the Solomons, little is known about their ecologies. I have collected nearly 1,000 observations of foraging behavior across a suite of islands, and have related these behaviors to morphology using museum study specimens. I am using this relationship to evaluate the extent to which behavior and morphology are decoupled following colonization of island systems. Using morphological metrics for behavior I am taking a broad look at shifts in behavior as they relate to the assembly history of flocks across the Solomons.
Species: The Elephant in the Room
Working on the birds of Northern Melanesia, it is impossible not to get entangled in species concept concerns. While I am interested in the philosophical underpinnings of different concepts, I also think that birds provide a wonderful opportunity for informing ecologists and evolutionary biologists working in less simple systems. In particular, microbial ecologists are generating incredible amounts of genetic data and are using these data to characterize microbial diversity across a huge range of scales. I am using birds to evaluate the importance of developing a philosophically sound and practically tractable species concept for microbial ecologists.