To the north, the Gulf of California xeric scrub transitions to the Sonoran Desert.

The principal shrubs are creosote (Larrea tridentata) and desert burr sage (Ambrosia dumosa), with Jatropha cinerea, palo fierro (Olneya tesota), Acacia brandegeana, Cercidium floridum, and Pithecellobium undulatum.

[2] Palm oases are found in stream valleys, and sustain a plant community that thrives with year-round moisture.

Threatened birds of the ecoregion include the masked bobwhite quail (Colinus virginianus ridewayi) and peninsular yellowthroat (Geothlypis beldingii).

Two of the oases - Oasis Sierra de La Giganta in the center, and Oasis de la Sierra El Pilar in the south - are Ramsar sites.