 The humid Oaxacan montane forests ecoregion lies below in elevation, on the eastern slopes above the Veracruz lowlands.To the east, the xeric Tehuacan Valley matorral ecoregion occupies the Tehuacan valley to the northwest, the Jalisco dry forests ecoregion occupies the upper basin of the Santo Domingo River, which lies in the rain shadow of the Sierra Madre de Oaxaca.The Southern Pacific dry forests ecoregion lies to the south along the Pacific Coast of Mexico, extending into the upper basin of the Tehuantepec River and the Valley of Oaxaca.