The forests of tropical South America host some of the highest biodiversity on Earth. In this project, an interdisciplinary team of geologists, climatologists, and biologists will take advantage of recent advances in their respective disciplines to develop an integrated understanding of how climate and geology interact to shape the distribution and generation of biodiversity in these Amazon/Andean forests through time. The Amazon and Andes are a dynamically linked highly interactive system. On long timescales, uplift of the Andes affects Amazon climate and hydrology. Andean uplift also generates the sediment fill, nutrient supply, river routing, and soil composition of the adjacent lowland basin of the Amazon and hence affects the productivity of its forests. But the interactions are bi-directional, because changes in climate, hydrology, and sediment supply influence rates of uplift through isostatic (buoyancy) effects produced by weathering and erosion. Together the multiple system components interact in complex ways to effect the origin and demise of new species and thus determine biodiversity. Today, this biodiversity is threatened by global climate change and other human activities. For example, a major emerging threat is the planned construction of headwater dams that will sever the transfer of nutrients from the Andes to the Amazon and impact the productivity and diversity of its forests and waterways. Thus, more than ever, there is a need for better understanding of the factors that foster the evolution and maintenance of biodiversity. The project is an interdisciplinary effort that unites scientists from both North and South America. It will support the education, training, and mentoring of undergraduate students, graduate students, and postdoctoral scientists at this exciting new frontier through the integration of fieldwork, laboratory studies, and modeling.
Before it is possible to quantify relationships between extrinsic forcings (e.g. climate, tectonics, hydrology) and the observed distribution of species through time, it is first necessary to generate accurately dated histories of the underlying geologic and climatic processes and to explore the governing rules for how environment influences diversity. The interdisciplinary team will undertake new detailed field and laboratory investigations of key aspects of the system components of the linked Andes-Amazon system, emphasizing: (1) determination of the history of Andean uplift, particularly in the oft-overlooked Western Cordillera; (2) a first attempt at reconstruction of a complete history of Cenozoic paleoclimate in the western Amazon lowlands; (3) isotope-enabled ocean-atmosphere climate modeling at key Cenozoic time slices; (4) molecular genetics of woody plant taxa carefully chosen to test several fundamental hypotheses about the role of uplift and climate in generation of diversity; (5) construction of an over-arching modeling framework (that incorporates new data on uplift, climate, and biota) linking paleo-topography, climate, hydrology, and nutrient cycling to plant traits, productivity, ecologic niche, and species distribution. The ultimate goal is to understand the role of environment and environmental history in genetic differentiation of populations and the origins of new species. By deciphering how environment affects biodiversity and, conversely, how genetic sequences of plant species encode the history of the physical environment, it is envisioned that molecular phylogenetics will inform geological history, much like paleontology informs stratigraphic and paleoenvironmental interpretation, and a new field of "geo-genomics" will emerge.
