The Site is composed of several protected areas and associated wetlands such as the Montecristi Underwater National Park, the Buen Hombre wetlands, the Cayos Siete Hermanos Wildlife Refuge, the Estero Balsa mangrove area and the Saladilla Lagoon. It encompasses a range of ecosystems including lagoons, mangroves, marshes, estuaries, swamps, dry shrub forests and coral reefs. In addition, the Site is home to a large proportion of the most representative coral reefs of the Dominican Republic. It hosts a considerable population of threatened marine turtles (Eretmochelys imbricata and Chelonia mydas). Moreover, four important bird species use the site for breeding (Anous stolidus, Onychoprion fuscatus, Thalasseus sandvicensis and Onychoprion anaethetus). The Site supplies the local communities with fresh water and food, and supports flood control, groundwater recharge and climate change mitigation. Both the coral reefs and mangroves in the area support a local fishery that provides a livelihood for many of the local people. The major threats that affect the Site’s ecological character are channelization and river regulation, proliferation of invasive species, the lack of garbage and solid waste management, agricultural and forestry effluents, and droughts.