During Pahse I, the SANREM Andean Program focused its primary research on the highland-lowland transect which roughly corresponds to the Guayllabamba-Esmaraldas River system that ecologically and hydrologically links the Andean mountains to the moist forests and mangroves along the Pacific Coast.
The Guayllabamba - Esmeraldas River system traversing NW Ecuador meanders some 180 kilometers through a rich natural and anthropogenic landscape representative of the tropical mountains and humid lowlands throughout the world. An altitudinal transect begins at sea level with the moist forest and mangrove ecosystems, passes through lowland wet forest, thence to the incredibly rich biodiversity zone of the mid-elevations (800-1200 masl) and finally to the hydrologically critical cloud forest and high zone páramo at almost 5000 masl. At each contour slice of this transect, one can find good examples of intact natural ecosystems side by side with examples of sustainable and unsustainable land use practices. In the mangroves, subsistence fishers make little impact on the natural resources while at the same time conversion of mangroves to other uses threatens their existence; in the lowlands complex agroforestry systems mimic many ecological aspects of the natural forest lands while monocultures face uncertain economic and ecologic futures; in the highlands the critically important environmental services provided by hydrological watersheds are threatened by urban expansion, a growing floral export industry, and poor quality pasture lands. Lying directly to the north of the Guayllabamba River and its upper watershed tributaries is the Cotacachi-Cayapas Ecological Reserve which is protected due in part by its international designation as a biodiversity hot spot. It is, however, threatened by logging, mining, and agricultural interests.