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Ecoregion Description


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Species Richness


# of Endemic Species


Threats

206: Chiriqui

Major Habitat Type:

tropical and subtropical coastal rivers

Author:

Scott Smith and William Bussing contributed material to this text.

Countries:

Costa Rica; Panama

Boundaries:

This ecoregion extends across Costa Rica and Panama, from the Tulín and Parrita-Candelaria drainage basins in the northwest to the western limit of the San Pablo and San Pedro drainage basins to the east.

Drainages flowing into:

Pacific Ocean

Main rivers or other water bodies:

From Punta Leona southward, coastal streams predominate until the large Rio Térraba and Coto drainages in southwest Costa Rica. The major drainage basins are the Rio Tarcoles, Rio Pirris, Rio Térraba, Rio General, Rio Coto, Rio Palo Blanco, Rio Chiriquí Viejo, Rio Escarrea, Rio Chico, Rio Plantanal, Rio Chiriquí, Rio Estero Salado, Rio San Juan, Rio San Felix, Rio Santiago, Rio Tabasara, Rio Bubi, Rio San Pablo, and Rio San Pedro (Smith & Bermingham 2005).

Topography:

The ecoregion is bounded by the Cordillera de Talamanca and the Cordillera Central, with elevations reaching over 3500 m above sea level. Southwest of the Cordillera de Talamanca are the interior valleys of the Rio General and the Rio Coto. These valleys are separated from the coastal plain by two ridges that form the Cordillera Costeña, a set of two hilly areas that for the most part lie below 1000 m in elevation, but have peaks that extend up to 1700 m. Protruding from the coast are the Peninsula de Osa and Peninsula Burica. The Peninsula de Osa forms the southwestern boundary of the Golfo Dulce, and Peninsula Burica is bisected by the Panama-Costa Rica border (Savage 2002). Peninsula Burica forms the western boundary of the Golfo de Chiriquí.

Climate:

Rainfall ranges from roughly 2500 mm in central Panama (Ridgely 1976) to over 3600 mm along the coast. Average annual temperatures range from 21o C in the Cordillera Central to 27 o C along the coast (World Wildlife Fund 2001).

Freshwater habitats:

Along the Pacific coast the ecoregion is marked by short, impetuous streams and few estuaries. Many of these short rivers empty directly into the Pacific Ocean or the Golfo Dulce. In the north is the Rio Grande de Pirris, a tributary of the Rio Parris that flows through deep gorges with steep, barren sides and later flows through dense forests. The lower valley of the Pirris is coverd by red clay, and thus unable to absorb rainwater. Since the waters do not readily drain off, they become stagnant (Keltie 1897). 

Another principal river system includes the southeastward-flowing Rio General (Chirripo) and the northwestward-flowing Rio Coto. These streams drain the southern slopes of the Cordillera de Talamanca and the northern slopes of the Cordillera Costeña. At their confluence near Potrero Grande the rivers become Rio Grande de Térraba, which runs through a deep, narrow gorge in the Cordillera Costeña toward the narrow coastal plain. At the mouths of the rios Térraba and Sierpe lie an extensive wetland system. The Térraba system has high stream flow most of the year, although it declines greatly during the dry season from January through April. In comparison, the Rio Grande de Pirris experiences more cyclic seasonal fluctuations (Savage 2002).

The rivers of the Pacific versant of Panama, located in the southeastern part of the ecoregion, are long and slow due to a shallower gradient and more extensive basins (Harmon 2005).

Terrestrial Habitats:

The lower elevations of the ecoregion are dominated by Isthmian-Pacific moist forests, whereas higher elevations are covered by Talamancan montane forests. An extensive mangrove area lies at the mouths of the Térraba and Sierpe rivers.

Fish Fauna:

There are more than 60 species of primary and secondary freshwater fish species in the Chiriquí ecoregion. The fauna is dominated by characids, followed by poeciliids and cichlids. The Pacific slope of Panama, owing to the large number of shared species between ecoregions, provides one of the clearest examples of facilitated dispersal among rivers along the same slope. Sixteen of the twenty-five species shared between the Chiriquí and the Santa Maria [208] ecoregions are also shared with the Tuira [210] ecoregion. It is probable that the nascent Isthmus was characterized by relatively little topographic heterogeneity and thus by relatively large drainage basins with very similar faunas among Pacific coast freshwater ecoregions (Smith and Bermingham 2005). This would have facilitated dispersal between ecoregions along the same slope at the time.

Description of endemic fishes:

The high endemicity of the Chiriquí province (30%) is probably the result of its increasing isolation from other freshwater ecoregions over geologic time. The hypothesis of increasing evolutionary independence of the Chiriquí and Santa Maria [208] ecoregions is supported by molecule-based phylogeographic analysis of widespread taxa across the LMA landscape (Bermingham and Martin 1998; Perdices et al. 2002). The endemic species of the Chiriquí ecoregion include six characids, Bryconamericus terrabensis, Hyphessobrycon savagei, Pseudocheirodon terrabae, Pterobrycon myrnae, Roeboides ilseae, and Astyanax kompi; one lebiasinid, Piabucina boruca; one eleotrid, Eleotris tecta; and three rivulids, Rivulus glaucus, R. siegfriedi, and R. uroflammeus. It also contains the following secondary freshwater fishes: two cichlids, Amphilophus lyonsi and Archocentrus sajica; and three poeciliids, Brachyrhaphis terrabensis, Poeciliopsis paucimaculata, and P. retropinna.

Other noteworthy fishes:

The semaphore tetra (Pterobrycon myrnae) is a relict species. The only other member of the genus is P. landoni, known from a single specimen collected in Colombia.

Other noteworthy aquatic biotic elements:

The Chiriquí ecoregion is within the South Central American Pacific Slope Endemic Bird Area, the center of abundance in the area of wetter forests around the Golfo Dulce and Osa Peninsula (BirdLife International 2008).

Nationally threatened aquatic birds like roseate spoonbill (Platalea ajaja) are found along the Pacific coast in this ecoregion. Also close to the Panama border are the sungrebe (Heliornis fulica) and sunbittern (Eurypyga helias) (Alvarado Quesada 2006). Partially migratory species that are regionally important include wood stork (Mycteria americana), bare-throated tiger-heron (Tigrisoma mexicanum), snowy egret (Egretta thula), and little blue heron (Egretta caerulea) (Alvarado Quesada 2006). The American wigeon (Anas Americana) is an uncommon migrant of this ecoregion (Angehr 2005). Other species include the great egret (Ardea alba), cattle egret (Bubulcus ibis), and black-crowned night-heron (Nycticorax nycticorax).

The wetlands within Chiriquí Province in Panama are especially important for the nationally threatened species of muscovy duck (Cairina moschata) (Angehr 2005). Lake La Yeguada (650 m) is one of few wetlands found at higher elevations in Panama and is a nesting area for pied billed gebres (Podilymbus podiceps) and least gebres (Tachybaptus dominicus).

More than twenty amphibian Red List species are found in this ecoregion. Most of these are frogs from eight genera, especially from the genus Isthmohyla, Craugastor, and Bufo (GAA 2006). The aquatic turtle of the species Rhinoclemmys punctularia ranges to southeastern Panama (Ernst 1978).

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 is good in this region.

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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