Sierra Madre del Sur

The Sierra Madre del Sur is a mountain range in southern Mexico, extending from southern Michoacán east through Guerrero, to the Isthmus of Tehuantepec in eastern Oaxaca.
Geography.
The Sierra Madre del Sur joins with the Eje Volcánico Transversal (Trans-Mexican Volcanic Belt) of central Mexico in northern Oaxaca, but is separated from this range further west by the valley of the Río Balsas and its tributary the Río Tepalcatepec.
The mountains' highest point is Cerro Nube – , in southern Oaxaca, and just one major highway crosses the range between Acapulco and Mexico City.
Although separated from the main part of the Sierra Madre del Sur by the deep canyon of the lower Río Balsas, the mountains of southern Michoacán around Coalcomán are usually considered part of the Sierra Madre del Sur.
Ecology.
The range is noted for its very high biodiversity and large number of endemic species.
The Sierra Madre del Sur pine-oak forests ecoregion occupies the higher reaches of the range. These forests are part of a chain of Mesoamerican pine-oak forests that stretch from the Southwestern United States to Costa Rica along the American Cordillera.
Lower elevations of the range are covered by tropical dry forests, ecoregions in the Tropical and subtropical dry broadleaf forests Biome. The Jalisco dry forests occupy the western end of the range's Pacific slope. The Southern Pacific dry forests occupy most of the Pacific slope of the range, from Michoacan in the west through Guerrero and Oaxaca. The basin of the Balsas River, north of the Sierra, is home to the Balsas dry forests.