Pre-contact Agave domesticates - living legacy plants in Arizona's landscape

Agaves played a central role as multi-use plants providing food, fibre and beverage to pre-contact and historical Mesoamerican cultures. However, their importance to Indigenous Peoples in the Southwest USA and northern Mexico, where they occur because of adaptations such as CAM photosynthesis, is less well known. Archaeological research indicates the Hohokam and other pre-contact Southwestern agrarian people increased agricultural potential in this region by engineering riverine terraces and bajadas for agave dry farming. Agricultural features such as terraces and rock piles were especially characteristic of post-1000 CE with the increase of dense, aggregated populations. We present an overview of six pre-contact agave domesticates (PCADs) the Hohokam and other cultures cultivated, and their ecological and cultural attributes. These PCADs are Agave murpheyi, A. delamateri, A. phillipsiana, A. sanpedroensis, A. verdensis and A. yavapaiensis.

Pre-contact agriculturists cultivated at least six once cryptic domesticated agave species in the modern Arizona landscape associated with pre-contact agricultural features, such as rock structures. Because of the longevity and primarily asexual reproduction of these agaves, relict clones have persisted to the present day, providing an opportunity to study pre-contact nutrition, trade, migration and agricultural practices. Taxonomic data imply that pre-contact farmers selected desirable attributes, initiating domestication processes that resulted in discrete lineages. These agaves are morphologically and genetically distinct from Southwest US and northern Mexico wild agaves and Mesoamerican wild and domesticated species. Additionally, the remnant clones present a rare opportunity to examine domesticates virtually unchanged since they were last cultivated prehistorically. These discoveries underline the need to view landscapes and some plant species from a cultural, rather than 'natural', perspective and discern potential cryptic species veiled by traditional taxonomic treatments. Protecting and understanding the distribution, and ecological and cultural roles of these plants require interdisciplinary collaboration between botanists, archaeologists, federal agencies and Indigenous Peoples.