CAREER: Islands as Models to Study Effects of Multidimensional Selection
This project will study the question of what governs the diversity of species using the Galapagos Islands, where factors influencing diversity range in their complexity. The islands of the Galapagos vary in age from young (less than 50,000 years old) to old (more than 4 million years old). This range in age can be used to study how biological diversity is shaped when communities are simple with few interacting species (on young islands), and when communities are more complex and characterized by numerous biological interactions (on older islands). This project will measure the rate at which new species are formed and diversity accumulates across a group of approximately 80 species of land snails forming the Galapagos's largest proliferation of species diversity. A combination of field and laboratory studies will be used to understand how the rate of evolution is influenced by the complexity of natural selection. A course for undergraduate students at the University of Idaho will introduce students to biodiversity patterns and guide them through the underlying evolutionary core principles generating these patterns using a series of field research excursions in the Pacific Northwest that is analogous to the Galapagos research expeditions. Students will also follow Galapagos research via Adventure Learning capsules (videos and integrated teaching material) which will guide and inspire them in the development of their own local research projects. Outreach activities also include developing a bilingual English-Spanish guidebook of Galapagos terrestrial snails, presentations and workshops for Galapagos park rangers, staff scientists, and guides, and disseminating research results in scientific publications, textbooks, magazines and the popular press. Islands are living laboratories where evolutionary change is clear, tangible, and can be directly observed. On Galapagos, the number of selection pressures increases from young to old islands as species assemble in more diverse and complex communities. Although substantial research efforts have been devoted to quantify selection in simple environments, there is a need to characterize the effects and interactions of multiple selection pressures in complex natural biological systems, and the proposed work will fill this gap. The project will characterize variation in morphological and physiological traits of snails and quantify variation in multiple environmental factors for the approximately 80 Galapagos endemic land snail species of the genus Naesiotus and their mainland relatives. Species-level phylogenetic history of the lineage will be reconstructed to determine the number of independent colonization events that led to the diversity of Galapagos Naesiotus snails, and put the phenotype-environment association analyses in a phylogenetically-informed framework. The data will then be used to address hypotheses related to the effects of multiple selection pressures (i.e., increased complexity) on the rate of phenotypic change and adaptation in this lineage. 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.