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Ecoregion Description


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Species Richness


# of Endemic Species


Threats

208: Santa Maria

Major Habitat Type:

tropical and subtropical coastal rivers

Author:

William Bussing and Scott Smith contributed material to this text.

Countries:

Panama

Boundaries:

This ecoregion lies on the Pacific side of Panama. The western border is formed by the Rio Santa Maria, Rio Tabasará, and Rio San Pedro drainage basins. The Soná Peninsula acts as an effective filter barrier separating this ecoregion with Chiriqui [206]. The Santa Maria ecoregion continues eastward and encompasses the streams of the Azuero Peninsula. The ecoregion’s eastern boundary is situated between Rio Sajalices (Santa Maria ecoregion) and the Rio Capira (Tuira ecoregion [210]). The ecoregion includes Coiba Island, which lies just off the southwestern coast of Panama.

Drainages flowing into:

Pacific Ocean, Golfo de Montijo, and Golfo de Panamá

Main rivers or other water bodies:

This ecoregion includes the following drainage basins: Rio Cate, Quebrada Seca, Rio Santa Maria, Rio Tabasará, Rio San Pedro, Rio Ponuga, Rio Tebario, Rio Pavo, Rio Playita, Rio Tonosi, Rio Cana, Rio Oria, Rio Guarare, Rio Honda, Rio La Villa, Rio Parita, Rio Cocle del Sur, Rio Chorrera, Rio Estancia, Rio Anton, Rio Farallon, Rio Chame, and the Rio Sajalices (Smith & Bermingham 2005). The main rivers are the La Villa, Santa Maria, and Cocle del Sur.

Topography:

The north of this ecoregion is flanked by the Cordillera Central. Altitude varies from sea level to 1500 m above sea level, with the highest elevations and mountainous terrain concentrated along the western side (up to 2000 m) of the peninsula (Suzan et al. 2006). Further east is the volcano El Valle, which rises nearly 1200 m. Coiba Island is the largest Pacific coast island in Central America.

Climate:

The area has a hot and humid tropical climate, with cooler temperatures at higher elevations. The mean annual temperature ranges between 20 and 27 °C. Mean annual rainfall declines along the central Pacific coast, where rainfall is aproximately 1200 mm per year. On the Azuero Peninsula the climate is extremely dry between January and April (Suzan et al. 2006).

Freshwater habitats:

The Pacific-oriented rivers of this ecoregion are longer and slower than rivers on the Caribbean side. Their basins are also more extensive. Mostly unnavigable, many originate as swift highland streams, meander in valleys, and terminate in coastal deltas (Library of Congress 1987). The rivers are characterized in general by their abundant flow volume.

The Santa Maria basin is the third largest in Panama (MINSA 2007). The once extensive fresh and brackish coastal wetlands found in the lower courses of the Rio Santa Maria and Rio Villa have since been converted to rice and sugar plantations (Angehr 2005). Near the Rio Santa Maria, Ciénaga de Las Macanas is the largest freshwater wetland remaining in the driest region of Panama (Angehr 2005).

Terrestrial Habitats:

The Santa Maria ecoregion historically consisted of Isthmian-Pacific moist forest throughout the western half of the ecoregion and Panamanian dry forests along the eastern edge. Today, the Azuero Peninsula is a mostly transformed agricultural landscape with low human density and scattered remnants of tropical moist and dry forests. The native vegetation consists predominantly of deciduous trees with some perennial and succulent species, grasslands, and mangrove swamps near the coast (Tosi 1971).

Mature forest covers large expanses of the central and northern part of Coiba Island with over 230 recorded species of plants, a large majority of which are trees and shrubs. The most speciose families are Leguminosae, Rubiaceae, and Melastomataceae. Higher elevation forests are dominated by Calophyllum longifolium, Eschweilera pittieri, Cassipourea elliptica, and Ternstroemia tepezapote, whereas Calophyllum longifolium, Tetragastris panamensis, and Carapa guianensis dominate the surrounding, low-lying forest. Pelliciera rhizophora and Rhizophora mangle are the most common species of the mangrove forests along the southern shore of the island, and freshwater swamps are characterized by high concentrations of Prioria copaifera and Peltogyne purpurea (Perez et al 1996).

Fish Fauna:

There are over 50 species of primary and secondary freshwater fish that inhabit the Santa Maria ecoregion. The freshwater fish communities are mainly composed of characids (23%) (primary freshwater fishes) and poeciliids (17%) (secondary freshwater fishes) (Smith and Bermingham 2005). The freshwater fish fauna of the Pacific slope of Panama, including the Chiriqui [206], Santa Maria, and Tuira [210] ecoregions, is characterized by a relatively low degree of faunal turnover. Sixteen of the 25 species of freshwater fishes that are shared between the Chiriqui [206] and Santa Maria ecoregionas are also shared with the Tuira [210] ecoregion. Moreover, 30 species are shared between the Santa Maria and Tuira [210] ecoregions.

Description of endemic fishes:

There is one endemic species of primary freshwater fishes in the Santa Maria ecoregion: a characid, Bryconamericus zeteki.

Other noteworthy aquatic biotic elements:

Some aquatic birds found in this ecoregion include the boat-billed heron (Cochlearius cochlearius), sunbittern (Eurypyga helia), great egret (Casmerodius albus), glossy ibis (Plegadis falcinellus), and common tern (Sterna hirundo) (Delgado 2005). The ecoregion is also home to important bird areas (IBA) such as the Pablo Arturo Barrios Wildlife Refuge in the southeast Azuero Peninsula, and the mouth of the Rio Tonosi, which contains small colonies of white ibis (Eudocimus albus) and black bellied whistling-duck (Dendrocygna autumnalis) (Angehr 2005).

Coiba Island is one of the few sites for the globally vulnerable brown-backed dove (Leptotila battyi) (Angehr & Montanez 2007).

The Ciénaga de Las Macanas wetland contains several nationally threatened species, including various ducks, and is the only known breeding site in Panama for killdeer (Charadrius vociferous) and fulvous whistling duck (Dendrocygna bicolor) (Angehr 2005; Delgado 2005).

Nearly five amphibian Red List species are found in the Santa Maria ecoregion, one of which, Craugastor azueroensi, is endemic to the Azuero Peninsula. The species belong to four genera: Atelopus, Hylomantis, Hyloscirtus and Craugastor (GAA 2006).

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 this area of Panama is fair. More ichthyological work is required in the drainage basins of the Azuero Peninsula. This is particularly true of the Rio Playita, Rio Pavo, Rio Oria and the Rio Cana drainage basins.

References/sources:

Bussing, W. A. (1976)"Geographic distribution of the San Juan ichthyofauna of Central America with remarks on its origin and ecology" In Thorson, T.B. (Ed.). Investigations of Nicaraguan lakes. (pp. 157-175) Lincoln, Nebraska: University of Nebraska.

Smith, S. A.,Bermingham, E. (2005). "The biogeography of lower Mesoamerican freshwater fishes" Journal of Biogeography 32(10) 1835-1854.

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