Boundaries

This ecoregion stretches along the coast from Guerrero south through most of Oaxaca to, but not including, the Tehuantepec basin. It encompasses numerous rivers on the southern slopes of the Continental Divide that drain into the Pacific Ocean.

Topography

The ecoregion covers the rugged Sierra del Sur, a mountain range with peaks reaching 3500 m asl. It includes a short piedmont and almost no coastal plain.

Freshwater habitats

Freshwater habitats are primarily a non-distinctive set of minor basins along short coastal plains. However, the Río Verde flows mostly over high plateau.

Terrestrial habitats

Terrestrial habitats include Southern Pacific dry forests along the coast and pine-oak forests at higher elevations.

Justification for delineation

Ecoregion delineations were based on qualitative similarity/dissimilarity assessments of major basins, using the standard administrative hydrographical regions of the Mexican federal government. This ecoregion is comprised of very small coastal basins, flowing from high mountains, with endemics only in the largest basin, Río Verde.

Level of taxonomic exploration

The level of taxonomic exploration is poor in general due to the highly mountainous terrain and few roads.