On the eastern coast of Nicoya Gulf, a short distance from Caldera Harbour, the landscape is composed of hills, tropical dry forest, cultivated terraces, points, cliffs, estuaries and mangrove swamps. A wide beach 3,5 kms long is bathed by the waters of the Pacific and serves as barrier for 670 hectares of mangrove swamp. The swamp shelters a wealth of wildlife and is fed by the River Jesús María. This saltwater forest contains all the species of mangrove known on the Pacific Coast of Costa Rica. The most important are the white mangrove, which in this swamp grows up to heights of 35 metres, and the black mangrove. The swamp is composed of 10 species of trees, 7 of shrubs and 5 herbaceous vegetation, as well as creepers, epiphites, ferns and palms.
The mangrove swamp on the Las Flores estuary, better known as Tivives, provides a habitat for over 60 species of birds, 25% of which are migratory. There are large colonies of amazons, including the yellow-headed amazon, parakeets and herons. Refuge is also found here by lizards, howler and white-faced capuchin monkeys, raccoons, grey squirrels, boa constrictors, rattlesnakes, grass snakes, ctenosaurs and several species of tortoise. Jaguarundies and ocelots have been seen on the edge of the beach.