EAGER: DISENTANGLING THE EFFECTS OF ECOLOGICAL CLADE SORTING AND ADAPTIVE DIVERSIFICATION TO THE ASSEMBLY OF REGIONAL BIOTAS

Missouri Botanical Garden, Saint Louis MO

Investigators

Abstract

The tropical Andes region of South America is among earth's most species-rich biodiversity hotspots. For example, 15% of all plant species (>45,000 species) occur in this region that covers only about 1% of the planet's land surface. To explain this unexpectedly high species diversity, this research team will investigate how environmental changes associated with the formation of the Andes Mountains influenced the distribution, diversification and evolution of tropical tree species in the region. Understanding the relationships between mountain uplift, environmental change, and species distributions is not only important to identify the causes of the remarkable Andean diversity, but also provides insight into how species respond to large-scale changes in environmental conditions. This information, in turn, can guide regional conservation and management aimed at conserving diverse and resilient biological communities. This project is unique because it is conducted over vast areas and deep evolutionary time scales. Because of the broad scope, project results are likely to significantly advance understanding of the long-term consequences of the emergence of novel environments for the formation and organization of biologically diverse communities. This project will test the the importance of elevational gradients for shaping community composition by integrating datasets on plant species distributions, functional traits and evolutionary relationships. Following mountain uplift, new environments at different elevations are hypothesized to promote (1) rapid adaptive diversification of clades, (2) immigration and ecological sorting of pre-adapted clades, or (3) a combination of both processes. This study will simultaneously explore these mechanisms and disentangle their relative contributions to the assembly of a hyper-diverse regional flora. This project leverages data from the Madidi Project that has already documented the elevational distribution of tree species in the Bolivian Andes. Distributional and elevation data will be integrated with a comprehensive database of plant-specimens for across the New World and elevational surveys of 10 plant functional traits. A large phylogeny of all seed plants will be developed and used to study turnover in species and functions among plant communities at different elevations and among biogeographic regions across the Neotropics. The project is somewhat risky because database uncertainties can be propagated in process modeling, but the geographic density of sampling could preclude such problems. However, there is high potential for revealing new insights into community assembly across shifting environmental gradients. 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.