Manglares Cayapas-Mataje Ecological Reserve, Nature reserve in San Lorenzo, Ecuador

The Reserva Ecológica Manglares Cayapas-Mataje covers 564.2 km² in the San Lorenzo canton of Esmeraldas province, between the mouths of the Río Cayapas and the Río Mataje, which forms the Colombian border. It was established on 26 October 1995 and combines coastal mangrove forest, evergreen lowland forest and dry scrub. Its 49,350 ha wetland system includes shallow marine water, tidal channels, estuaries and the freshwater Laguna de La Ciudad, a lagoon about 2 m deep with water lilies and floating vegetation.

The reserve was established on 26 October 1995, covering 564.2 km² of mangroves, evergreen lowland forest and dry scrub between the Cayapas and Mataje river mouths. In 2003, 44,847 hectares were designated a Ramsar wetland site. BirdLife International later classified it as an Important Bird Area.

Twenty-six Afro-Esmeraldas communities live inside the reserve, among them settlements reached by boat along the Cayapas and Mataje estuaries. Around the shallow Laguna de La Ciudad, roughly 2 m deep, residents grow citrus, plantain, babaco, cacao, maize and cassava mainly for their own consumption rather than for sale.

The reserve lies in San Lorenzo Canton, Esmeraldas, between the mouths of the Cayapas and Mataje rivers, reaching from La Tola and Borbón to the Mataje mouth on the Colombian border. The rainy season runs from December to June. A border post sits at Ancón, inside the reserve.

The reserve's wetlands form the largest and best-preserved estuarine system on the South Pacific, covering 49,350 hectares of shallow marine water, tidal channels, estuaries and intertidal forest. Within it lies the Laguna de La Ciudad, a shallow 2-metre freshwater lagoon with floating vegetation such as Nymphaea glandulifera and Azolla carolina.