Relict Plant Communities at Prehispanic Sites in Oaxaca, Mexico: Historical Implications

Coordinated with excavations at two prehispanic sites in the eastern arm of the Valley of Oaxaca, Mexico, we documented a diversity of economically useful plants at both localities. Many plants that abound at El Palmillo and the Mitla Fortress are used locally as food, medicine, and in ritual activities. These hilltop settlements were abandoned during the prehispanic era and never resettled, leaving relict floral communities that were once tended by their prehispanic inhabitants. A comparison of plant communities at El Palmillo, the Mitla Fortress, and other locales in the Valley of Oaxaca illustrates the higher incidence of xerophytic plants in the drier eastern (Tlacolula) arm of the valley, with the greatest abundance in archaeological contexts. These findings affirm the importance of a broad array of succulents (especiallyAgavespp.), yucca, and cacti for the region's inhabitants, thereby helping account for the dense prehispanic populations that resided there.