This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Landsliding is a complex process that influences carbon budgets in mountainscapes worldwide. This interdisciplinary project seeks to understand the relative contribution of landsliding and deforestation to land-cover change and ultimately, their role in transferring and storing organic carbon in the Sierra de Las Minas, Guatemala. Using a set of contrasting watersheds - dry and wet - this project will address three primary goals: 1) quantify the contribution of deforestation and landsliding to land-cover change, 2) examine the coupling between landslides and streams, and 3) estimate carbon fluxes associated with landsliding and deforestation. Land-cover data obtained from remotely sensed images taken at many points in time, and carbon-content data obtained from field sampling of vegetation, soil, and water, will be combined in a geographic information system (GIS) to model carbon storages and fluxes.
This project will contribute to the education of a new generation of scientists in an emergent field that recognizes important links between Ecology and Earth Sciences. This goal will be accomplished by engaging students traditionally under-represented in science across educational levels in a variety of activities, including field work, satellite image analysis and modeling, and laboratory analyses. Students will also benefit from the cross-cultural aspects of interdisciplinary scientific research in international settings. Results of this project will improve the knowledge base needed for carbon mitigation projects in tropical regions, and will enhance our understanding of carbon cycling and sequestration in the context of climate change, hazard assessment, and forest conservation.
The project conducted in the Sierra de las Minas of Guatemala, in collaboration with researchers and students from the University of Puerto Rico-Rio Piedras, proposed novel questions about regional causes and consequences of landsliding that were intended to inform both basic and applied science. The results generated contribute to climate change, hazard assessment, and environmental conservation. Results of our studies, both on organic carbon transport in streams, and on chemical weathering of silicate minerals in streams, generated from this project, have improve regional-scale estimates of carbon dynamics on timescales directly relevant to carbon mitigation projects. In terms of hydrology and stream flow, the project has contributed to a better understanding of ways in which land use influences landsliding in tropical mountainscapes and those results may help in the formulation of landslide susceptibility models with increased predictive power. In particular, the project has provided datasets on stream flow in ungauged basins and shown the significant role of orographically-controlled precipitation in the timing and generation of streamflow in mountainous terrains. A better understanding of the process of landsliding in natural ecosystems is helping to evaluate the impact of widespread landsliding in protected mountainscapes and set management protocols for these areas. Carbon dioxide consumption as a result of silicate mineral weathering in watersheds draining the Sierra de las Minas in Guatemala were quantified and shown to be similar to that observed in other active mountain regions worldwide. The results underscore the importance of these rapidly uplifting areas in the global carbon cycle and global climate forcing. This study also supports the positive relationship between annual precipitation and chemical yields that has been observed elsewhere. This relationship may be influenced by mountain uplift causing local orographic increases in precipitation. Extreme storm events such as typhoons and hurricanes have been shown to transport a large percentage of the annual particulate organic carbon transport. This transport of particulate organic carbon can be a sink of atmospheric CO2 if it is buried and removed from the atmosphere before it is consumed and oxidized. In 1998, Hurricane Mitch triggered widespread landslide activity throughout the Sierra de las Minas that mobilized material, including particulate organic carbon. Here, relationships among carbon and nitrogen concentrations and δ13C in streambed sediments and shale were used to speculate on the fate of material mobilized by landslides during Hurricane Mitch. These speculations are supported by satellite observations made immediately following Hurricane Mitch that map the extent of landslide scours. Much of the landslide transported organic carbon appears to have been efficiently removed from the fluvial-hillslope interface and buried. These observations are supported by the noted importance of event controlled carbon export in regional organic carbon yields. This project contributed to the education of a new generation of scientists in an emergent field that recognizes important links between Ecology and Earth Sciences. This goal has been accomplished by engaging Ohio State students in field work, satellite image analysis and modeling, and laboratory analyses. The Ohio State graduate students gained professional skills in writing manuscripts and in presenting their research at professional conferences. The two undergraduate and two graduate students benefited from the cross-cultural aspects of interdisciplinary scientific research, conducted with students from Puerto Rico and Guatemala in a remote international setting in central Guatemala. The Ohio State students presented their research to elementary and high school students in small villages in Guatemala, thereby contributing to international understanding and education.
