Boundaries

The Estero Real – Tempisque ecoregion is a narrow strip along Central America’s Pacific Coast, extending from the Golfo de Fonseca in the north to the Golfo de Nicoya in the south. It is bordered by the Cordillera Dariense in the north, by the Cordillera de los Marrabios in the northeast, and the Cordillera de Guanacaste in the south. The Río Negro runs along the Honduras-Nicaragua border and represents the northern boundary of the ecoregion; this drainage flows into the Estero Real at the southern end of the Golfo de Fonseca. A faunal barrier is reached near Punta Leona, Costa Rica; the divide between the Río Tarcoles and the Río Pirris forms the southern boundary of this ecoregion.

Topography

Most of the Estero Real – Tempisque ecoregion lies along a narrow coastal plain that is broken by volcanic and sedimentary hills that sometimes form low cliffs along the coast. The eastern edge is bordered by the Nicaraguan lakes and by mountains that rise to elevations upwards of 1000 m. The Pacific littoral is marked by many rocky headlands and three peninsulas. Cosigüina Peninsula forms the northwest corner of Nicaragua. It is bounded to the west by the Pacific Ocean and to the north and east by the Golfo de Fonseca. The peninsula is a flat plain dominated by the Cosigüina volcano (859 m) (Milner-Gulland and Mace 1998).

The Peninsula de Santa Elena lies in northwestern Costa Rica between the Golfo de Santa Elena and the Golfo de Papagayo. The Peninsula de Nicoya forms the southern boundary of the large, shallow Golfo de Nicoya. This peninsula is divided by a series of low ridges between 500 and 900 m in elevation that run down its center (Savage 2002).

The Golfo de Nicoya contains a number of low-lying islands. Most of these islands, except off the tip of the peninsula, and the shoreline of the gulf itself, are bordered by extensive mudflats and mangroves (Savage 2002).

Freshwater habitats

Rivers of the Pacific coast are short, and many of the smaller rivers are intermittent. Rivers within the Pacific drainage of Costa Rica, especially in the Guanacaste province, have greatly diminished flows during the dry season. Most streams in the lowlands dry up for several months during the dry season, while showing high basal flows with zero to several flood-causing periods a year during the rainy season (pers. obs., 1987-1992 de la Rosa 1995). Landslides are common among the upper reaches of many rivers that flow through primary forest in Central America’s volcanic chain. These landslides cause massive inputs of organic and inorganic matter to the streams, and open wide sections of the canopy cover, allowing sunlight to penetrate to the stream bottom (de la Rosa 1995).

Terrestrial habitats

The Pacific coastal plain north of the Punta Mala promontory receives much less rainfall than the Atlantic lowlands or southern Costa Rica  (Bussing 1976). Semi-deciduous dry forest was historically the predominant vegetation type in this area, extending from southern Chiapas to Guanacaste (World Wildlife Fund 2001). Much of it has since been degraded or converted. Other terrestrial habitats within the ecoregion include the Costa Rican seasonal moist forests and Talamancan montane forests (World Wildlife Fund 2001). The Southern Mesoamerican Pacific mangroves line portions of the coast, with the largest area around the Gulf of Fonseca.

Description of endemic fishes

There are no known endemic species in the Estero Real - Tempisque ecoregion (Smith and Bermingham 2005). Many of the fishes of this ecoregion are shared with the San Juan ecoregion [205] on the Caribbean slope. Further ichthyologic investigation is required in the northern Nicaraguan portion of this ecoregion to confirm the absence of endemics.

Other noteworthy fishes

Five species that are widely distributed throughout the San Juan ecoregion [205] (Caribbean versant) inhabit small pockets in this ecoregion, principally in Guanacaste Province, Costa Rica: Alfaro cultratus, Rivulus isthmensis, Astatheros alfari, rainbow cichlid (Herotilapia multispinosa),and guapote (Parachromis dovii).

Justification for delineation

Fish provinces from Bussing (1976) were revised and subdivided on the basis of application of a similarity index to sub-basin fish presence/absence data.

Level of taxonomic exploration

The level of taxonomic exploration in the southern part of the ecoregion is good; more ichthyologic work is required in the northern section.