Friday, April 5, 2019

Hunting the ancient agave

Agaves spend much of their lives as toothy, spikey plants we avoid while hiking. Most agaves bloom only once, throwing their heart and carbohydrates into raising an exorbitant stalk of fragrant flowers that ripen into dry fruits stacked with flat, black seeds. We're captivated by the transformation from spikey to florescent.

Wendy Hodgson makes agave seeds fly in Cascabel.
However, for over 8,000 years, people have harvested agaves just before flowering, usurping the carbohydrates in the stem for human food and beverage. The leaves also provide fibers for rope, baskets, bags and sandals.

Although people have used agaves continuously in Mexico, the plants' cultivation and culture faded from what is now Arizona by the 16th century. Residents of the Middle San Pedro Valley have periodically wondered if we could grow agave in our area. After all, Sobaipuri Native American agave fields dot our community, and wild agaves grow in the valley.

When this question came up again last winter, we learned that survivors of pre-Columbian cultivated agave had recently been found in our area. Wendy Hodgson and her colleague Andrew Salywon, both with the Desert Botanical Garden, named the new species Agave sanpedroensis. Wendy and Andrew even suggested that this low-water-use crop could be revived to diversify agriculture and stimulate new industries in the U.S. Southwest.

Agave sanpedroensis.
We contacted Wendy, who was as eager as we were to connect. In January 2019, she told a packed Cascabel Community Center about the eight (and counting) species of formerly cultivated agaves she and her colleagues have found. In February, dozens of people braved blustery weather on a follow-up field trip. Wendy explained how she recognizes the different species of agaves and outlined how we can help her survey the plants in our valley.

Wendy and Andrew work with archaeologists, who have documented extensive agave fields at many sites in central and southern Arizona. Rows of rocks along contour lines slowed runoff across the fields and rock mulch piles reduced evaporation. Near the fields, archaeologists find knives used for removing leaves and roasting pits where agave stems, or "heads," were baked to sweetness.

The plants we see today are genetically identical to those the Sobaipuri and other groups developed to suit their needs. Unlike their wild relatives, these cultivated agaves produce little or no seed. Instead, the plants reproduce vegetatively, usually by pupping, to produce offspring identical to the parent. Cultivated agaves are also sweeter than their wild relatives and their leaves are easier to cut.

After surviving drought, insects, and rodents for centuries--or millennia--climate change and development threaten these rare plants. As cultivated crops, they fall into a protection gap: the Endangered Species Act protects only wild species and the Archaeological Resources Protection Act protects only inanimate artifacts.

Wendy fears that these recently discovered, living storehouses of information on people, culture, and plants could be lost. She is helping residents of the Middle San Pedro Valley learn about the ancient agaves in their area and work to protect them.

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