Deciphering natural hazard histories based on tree-ring analyses in contrasting tropical ecosystems of Costa Rica

Climatic and anthropogenic changes are contributing to the degradation of tropical river basins in Costa Rica, thereby resulting in an increase in flood and landslide disasters. Strategies aimed at mitigating disasters are mostly based on empirical observations, which can allow for the detection of climate-process linkages during past events, and thus inferences for the future. Such assessments, however, need to rely on long-term data, which is rarely available in Central America. This research proposal aims at the development of innovative, long-term baseline records of past disasters based on tree-ring analyses, as a basis for an improved understanding of relationships between past/recent climatic variability and/or change and land-use changes affecting critical ecosystems of tropical river basins. The working hypothesis of this PhD proposal is that the degradation of tropical river basin will have an impact on ecosystem functioning, thereby leading to an exacerbation of hydro-geomorphic processes and their impacts on local populations. The innovative nature of this research can be described by the very limited experience available in terms of tree-ring analysis in Costa Rica and the clear lack of understanding on past disasters and climate linkages in highly (bio) diverse tropical environments. This approach will contribute to the implementation of future adaptation strategies in a country where current deforestation is about to put at risk its rich biodiversity (containing approximately 5% of the World’s biodiversity). This project will be based on aerial imagery analysis, meteorological assessments, and the study of historical data, fieldwork, sampling and treering

analysis.