The tropical forests that circle the equatorial belt of Earth are home to vastly more plant species than the temperate zones that extend toward the poles. Biologists have tried to explain the difference in biodiversity between tropical and temperate regions for centuries, but efforts have been hindered by limited data, particularly among plant groups. Nevertheless, understanding these worldwide patterns is fundamentally important to understanding these patterns in natural systems in the U.S., where plants play a key ecological and economic role. This research will provide a detailed study of a diverse and globally distributed group of plants, known as the Ericales, that includes a variety of economically important species such as blueberries, kiwi fruit, persimmon, Brazil nut, timber woods (e.g., ebony), azaleas, rhododendrons, and even carnivorous plants. These newly collected "big data" resources will allow researchers to discover genetic and morphological factors that contribute to the origin and maintenance of the biological diversity in Earth's forests. This research will also promote the training of the next generation of young STEM researchers to be fluent in application of computational and plant genomics resources to challenges facing the nation.
The staggering diversity of tropical plants contributes to a latitudinal diversity gradient of increased species richness towards lower latitudes; a pattern found across the tree of life. Despite the significance of tropical biomes and the evolutionary/ecological importance of movements across, into, and out of tropical latitudes, the sparse sampling of species for both DNA sequences and morphological traits has inhibited progress in addressing major evolutionary questions regarding the origin, diversification, and niche evolution of lineages with temperate and tropical transitions. This research is positioned to overcome these limitations, using the diverse and ecologically important plant clade Ericales as a case study. The researchers will use transcriptome and targeted-capture sequencing to resolve phylogenetic relationships and characterize gene and genome evolution within the Ericales at an unprecedented scale to produce a robust species-level phylogeny combined with paleobotanical data, morphological traits (including habit and floral), and information regarding species niche to evaluate the intrinsic and extrinsic correlates of tropical and temperate diversification. They will conduct analyses that address specific questions of broad interest: 1) What are the major drivers of diversification and evolution between the temperate and tropical lineages? 2) Do adaptations to new environments lead to faster rates of both molecular evolution and diversification? 3) Are differences in rates of evolution between lineages in different biomes and different elevations reflected in individual species geographic and niche evolution patterns? 4) What biogeographic histories and adaptations underlie the highly diverse and threatened tropical montane biomes?
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.
