Patterns of community assembly and evolution of body size variation in the Accipiter-complex, a cosmopolitan hawk clade

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Although hawks are among the most charismatic bird groups, we know surprisingly little about how species of hawks are related to each other, how their communities have assembled over earths history, and even how many species there are on our planet. In particular, hawks that live on remote islands are poorly known and many are considered members of single widespread species, yet several of the island dwelling hawk populations are sufficiently distinct that they should be considered separate species unique to these islands. Using next generation DNA sequencing, this research is determining how many species of hawks coexist with one another and how the species are related. The researchers are using these data to determine whether the hawk communities on islands assembled over earth’s history via a single colonization followed by diversification or whether multiple hawk lineages independently colonized the same islands. By comparing the observed patterns across oceanic islands to the patterns of community assembly of hawks on mainland regions, this project will identify differences between how communities are created in these two types of landforms. This project is among the first to reconstruct community assembly patterns of a globally distributed bird group. Lastly, the team is examining over 10,000 hawk specimens from around the world to place hawks into functional ecological groups and identify natural history characteristics (such as typical prey types), which are unknown for many of the rarer hawk species. The researchers are partnering with The Women in Natural Sciences (WINS) program at the Academy of Natural Sciences of Drexel University to expose female high school students from disadvantaged backgrounds to STEM fields. The team is coleading hawk-watching field trips for all participants, and each summer a WINS student is working on the project as a research assistant on the project. This project is also supporting the early career development of the lead PI, a Hispanic American. Both PIs are researchers at a large public museum and are disseminating project results at public outreach events. Lastly, by identifying islands and regions harboring unique species, conservation resources can be better directed towards the areas or species in greatest need. Reconstructing the patterns and processes of community assembly are critical for understanding the ecology and evolution of biotas. Communities can be formed in several ways and one prediction is that communities on oceanic islands are assembled via clustering (a single dispersal followed by speciation), whereas continental communities are assembled via multiple dispersal events. The Accipiter hawk complex includes approximately 180 currently valid, named taxa (species and subspecies) that occur on both continental and island land masses. Even on remote islands, multiple behaviorally and ecologically similar, but variably sized Accipiter-complex hawk taxa are found in the same ecological communities making this hawk complex an ideal group for testing community assembly patterns on a globally distributed group. This project includes four objectives: 1) reconstruction of a subspecies level phylogeny of the Accipiter-complex, 2) identification of geographic regions with multiple Accipiter-complex members overlapping in geographic distribution, 3) characterization of size and natural history classes of these hawks based on morphological examination, 4) identification of community assembly patterns in the Accipiter-complex. To accomplish these objectives, the researchers are sequencing genomes to reconstruct a phylogeny for all currently recognized subspecies within the complex using existing specimens, creating detailed range maps for each Accipiter-complex member, and reconstructing community assembly patterns for this complex across the globe.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.