Balsas dry forests


The Balsas dry forests is a tropical dry broadleaf forest ecoregion located in western and central Mexico.

Geography

The Balsas dry forests occupy the basin of the Balsas River. The ecoregion covers an area of. The Balsas basin, and the Balsas dry forests, extend east and west between the ranges of the Trans-Mexican Volcanic Belt to the north and the Sierra Madre del Sur to the south.
The Balsas dry forests ecoregion extends across portions of the states of Michoacán, Guerrero, Mexico, Morelos, Puebla, and Oaxaca.

surrounding ecoregions

The surrounding mountains are home to pine-oak forests: the Trans-Mexican Volcanic Belt pine-oak forests to the north and northwest, the Sierra Madre del Sur pine-oak forests to the south, and the Sierra Madre de Oaxaca pine-oak forests to the east. The xeric Tehuacán Valley matorral lies to the northeast. The Balsas dry forests meet the coastal Southern Pacific dry forests where the Balsas breaks through the Sierra Madre del Sur on its way to the Pacific Ocean.

Climate

The climate of the Balsas dry forests is tropical and subhumid. Rainfall is less than 120 centimeters per year and seasonal, with a dry season that can last up to eight months.

Flora

Plant communities include tropical deciduous forest and thorn forest, with tropical semideciduous forest in drainages and other areas with deeper soils and more soil moisture.
Characteristic trees include several species of Bursera – Bursera longipes, B. morelensis, B.odorata, etc. – commonly known as palo mulato, fragrant bursera, and chupandra. Other common trees include pochote, brasiletto or mexican logwood, Lysiloma microphylla, and cazahuate. Cacti are common, including species of Pachycereus and Cephalocereus.
The herbaceous layer is generally sparse, with the grasses sideoats grama, Rothrock's grama, and Hilaria semplei.
The Balsas dry forests share many species in common with Mexico's Pacific coastal dry forests. Many plant species are endemic to the ecoregion. About 45% of the species at a site in Cañón del Zopilote, Guerrero, and 30% of species at a site in Infiernillo, Michoacán are found only in the Balsas basin. About half of the 45 species of Bursera found in the ecoregion are endemic. The ecoregion is also home to diverse species of Brongniartia, Desmodium, Ipomoea, and Mammillaria.

Fauna

Native mammals include the jaguar, jaguarundi, ocelot, collared peccary, coyote, grey fox, white-nosed coati, and silky pocket mouse, California myotis, long-legged myotis and western yellow bat.
The Balsas screech owl, banded quail, black-chested sparrow, and dusky hummingbird are near-endemic bird species.
Portions of the ecoregion are part of several Important Bird Areas, including Sierra de Taxco–Nevado de Toluca, Cañón del Zopilote, Valle de Tehuacán–Cuicatlán, Cañón de Lobos, Sierra de Huautla, and Papalutla-Tecaballo.

Protected areas

10.9% of the ecoregion is in protected areas. A 2017 assessment found that 1,451 km2, or 4%, of the ecoregion was protected.
Protected areas include: