The water-energy-food nexus through the valuation of ecosystem services in an Andes-Pacific transboundary catchment.

Global change has economic, environmental, and social impacts that threaten access to water resources for communities and ecosystems globally. Mismanagement in other sectors, such as food and energy, can further reduce water security. Scientists use the water-energy-food (WEF) nexus as a conceptual tool to identify the interactions between these three systems. Its implementation at natural-local scales (catchments) is essential for proposing sound policies for water resource management and adaptation to global change.
This study aims to identify synergies and trade-offs between WEF through the valuation of related ecosystem services in an Andean-Pacific transboundary catchment of Ecuador and Colombia (Mira-Mataje - 11,791 km²). We used remotely- sensed and globally available datasets in the spatially distributed assessment model Co$tingNature, to first screen interactions of the related ecosystems. Subsequently, we analyzed the polycentric knowledge from stakeholder’s: Non-Governmental Organizations (NGOs), community leaders, academics, and State sector workers. Finally, we combined the above analyses into a WEF-related ecosystem services weighted-hypernetwork.
Preliminary results show that some services related to energy and food production have negative impacts on water security throughout the catchment. We identify a significant overlap between areas rich in ecosystem services and ancestral territories of ethnic communities and recognize some key intensive anthropogenic activities that affect water security. In addition, we confirm the paramount dependency of Andean cities on water supply from mountain ecosystems. We identified a widespread perception among stakeholders that WEF-related ecosystem services are at risk due to global change and that, in different ways, all are taking steps to adapt to global change. Finally, there is the potential availability of water service in medium and low catchment areas, although the challenge is to improve distribution and purification systems to supply rural areas and make water service accessible to all.

Keywords: Ecosystem services, water-energy-food, remote sensing, weighted-hypernetwork, local knowledge, transboundary tropical catchment.