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Silt of the Earth

Natalia Estrada

Though she doesn't get her feet dirty, Natalia Estrada, a second-year student in the joint doctoral program between the University of Idaho and the Tropical Agricultural Research and Higher Education Center (CATIE) in Costa Rica, carries out important soil erosion research.

Mentored by Alex Fremier, assistant professor of fishery resources, and Fabrice DeClerck, professor of landscape ecology at CATIE, Estrada's studies will provide strategic information for promoting target payments for ecosystem services that can be monitored and evaluated over time and space.

"I chose the University of Idaho/CATIE joint doctoral program because it embraces diversity and offers a wide range of conservation research in natural and managed ecosystems in the temperate and the tropics," says Estrada. "If you are not from the U.S., this is a place where you can easily adjust to the community because of the friendly, supportive faculty, staff and students."

By using innovative methodologies developed at the University of Idaho, and elsewhere in the U.S., and applying them to tropical conditions, Estrada conducts remote sensing (satellite imagery) and modeling that can pinpoint exactly where soil erosion is a problem.

Costa Rica in particular loses about 860 million tons of valuable topsoil every year due to heavy tropical rains and deforestation. Widespread soil erosion and sediment build up have negative cascading effects that impact the efficiency of hydroelectric dams and the cost of energy, and also put sensitive ecosystems at risk.

By identifying these erosion "hot spots," Estrada can transfer knowledge to Costa Rica's national funding agency in charge of assigning and regulating payments for ecosystem services.

Payments for ecosystem services are a type of economic instrument that promotes conservation and the implementation of sustainable agricultural practices like agroforestry systems. These systems help control soil loss on farms and provide other ecosystem services such as carbon sequestration, pest control functions, pollinization, habitat, and landscape connectivity for plants and animals dispersion, and others.

Armed with the information from Estrada's results, dam operators who are willing can target payments to farmers located in the hotspots areas. Farmers then are recognized by implementing agricultural practices that help to retain the soil that provides the ecosystem service of soil erosion control. This strategy will help dam operators reduce the amount of money expended annually to remove the sediments in the dams and repair damages, and it may contribute toward improving farmers' livelihoods.

Estrada is specifically focusing on the watersheds that are in biological corridors in Costa Rica. These regions are important because they sit between protected areas and provide for the livelihoods of thousands of Costa Ricans who produce coffee, sugar and other tropical crops.

Estrada studies the Volcanica Central-Talamanca Biological Corridor, which has high precipitation and is located on Caribbean side of the country. She also is focusing on the Hoja Ancha Biological Corridor located on the Pacific Ocean side, where a regular dry season makes strategic conservation of forests to protect water sources particularly important. Estrada explains it is important to evaluate both rainy and dry regions because water bodies in each can have differing amounts of sediment load.

"Some ecosystem services are not provided equally throughout the landscape," says Estrada. "By quantifying soil erosion on the landscape level, we can determine the best investment scenarios in areas where ecosystem services are really needed."

Estrada says Costa Rica is developing broader definitions of conservation that apply not just to the land but to the people who depend on it.

"Economic evaluation and assessment of ecosystems services help to develop efficient and effective biodiversity conservation strategies that also can alleviate poverty," she says. "I am hoping to improve the efficiency of payments for ecosystem services."

Raised in Colombia, Estrada feels called to continue working on natural resource conservation issues in Central and South America after she graduates.