Linking ecosystem and geomorphic processes to understand the large-scale dynamics of tropical mountains mediated by landsliding

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Landslides are an important agent of change in mountain settings worldwide. Although the basic geological processes underlying landslides are relatively well known, increasing evidence indicates that the living components of ecosystem processes play an important, but largely understudied, role. In particular, plant root and shoot biomass - two important ecosystem attributes - are likely to influence the stability of hill slopes in complex ways. This project investigates the relationships between soil fertility, climate, ecosystem attributes, and slope stability in the Sierra de Las Minas, a mountain range in eastern Guatemala. This study area was selected because it is subject to periodic landslides and has a considerable history of previous research. The project integrates for the first time basic ecosystem concepts to better understand the evolution of landforms and landslides, suggesting that the division of vegetation biomass between roots and shoots is critically important. This is a highly interdisciplinary project that also will contribute to the engagement of women and underrepresented minorities in research and outreach, forge international collaborations, and provide for the dissemination of new knowledge that will be of interest to a wide range of stakeholders and scholars, including those interested in landform evolution, ecosystem and landscape development, carbon cycling, and sustainable management of regions subjected to landslide hazard.Building upon previous work, this project takes advantage of the diverse lithologies and contrasting climates found in the Sierra de Las Minas, to test the overall hypothesis that variation in soil fertility inherited from different lithologies influences the partitioning of biomass between roots and shoots with consequences for slope stability, soil development, and ultimately landslide regimes. Variation in climatic conditions, however, may change the magnitude and direction of the observed effects. The work is organized around three specific goals and corresponding hypotheses: 1) examine the relationship between soil fertility and vegetation attributes that influence slope stability, 2) investigate differences in soil development trajectories in landslides underlain by different parent materials, and 3) evaluate the interactions between different soil fertilities and vegetation dynamics on landslides. These goals will be developed using a combination of geographic information systems and remotely sensed data, fieldwork, tree-ring studies, biogeochemical and geochronological analyses, and modeling.