Tehuacán-Cuicatlán Valley: originary habitat of Mesoamerica

• Official name: Tehuacán-Cuicatlán Valley: originary habitat of Mesoamerica
• Location: Puebla, Mexico, and Oaxaca, Mexico
• Type: Natural and Cultural
• Year of inscription: 2018

Tehuacán-Cuicatlán Valley, the originary habitat of Mesoamerica, is in the Mexican states of Oaxaca and Puebla, spanning 358,932 acres (145,255 hectares). The World Heritage site contains both cultural and natural features, including critically endangered cacti, agaves, yucca, and oaks. Archaeological remains demonstrating early crop domestication are also there. Evidence exists of human adaptation and development spanning more than twelve thousand years.

Tehuacán-Cuicatlán Valley consists of three parts: Zapotitlán-Cuicatlán, San Juan Raya, and Purrón. The valley harbors the richest biodiversity of an arid or semi-arid zone in North America, and it is home to the densest forests of columnar cacti in the world. Located within the Tehuacán-Cuicatlán Biosphere Reserve, the property is a global biodiversity hotspot.

Life in such an arid environment propelled two major innovations in civilization: water management systems and the domestication of plants such as maize (corn). The area’s archaeological remains display what was once an exceptional water management system consisting of canals, wells, aqueducts, and dams. This system is the oldest on the continent and enabled the development of agricultural settlements in the valley.

Technological advances in water management also helped propel the discovery of other innovations, like the salt industry and pottery. Archaeological remains at Tehuacán-Cuicatlán include rock paintings, graves, mounds, and citadels from the time when hunter-gatherers transitioned into settled farmers.

History

Tehuacán-Cuicatlán Valley’s natural biodiversity and arid desert environment gave rise to one of the largest and best-documented sequences of human adaptations in history, which took place over a span of more than twelve thousand years. The site’s archaeological remains show early technological developments and the early domestication of crops like maize.

In the 1960s, American archaeologist Richard S. MacNeish and his team did a large-scale survey of the Tehuacán Valley. The survey identified nearly five hundred cave open-air sites, including three that were occupied for ten thousand years: San Marcos, Purrón, and Coxcatlán caves. The excavation of these caves led to the discovery of the earliest appearance at the time of domesticated plants including maize, bottle gourd, squash, and beans. These excavations also recovered more than one hundred thousand plant remains and artifacts.

Historians have found it difficult to date Coxcatlán. Radiocarbon dates for organic materials like carbon and wood were not consistent, likely due to displacement by human activities like pit-digging or rodent/insect disturbance. This led to controversy into the 1970s and 1980s about the validity of the dates for the first maize, squash, and beans. In the late 1980s, new radiocarbon dating techniques helped re-date the crops: Cushaw gourds were dated at 115 BCE, common beans were dated at 380 BCE, maize was dated at 3,540 BCE, bottle gourd was dated at 5,250 BCE, and pumpkins and zucchini were dated at 5,960 BCE.

While the area was not designated as a United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Site until 2018, it has been under state protection since 1998. In 2012, it was declared a biosphere reserve. According to the International Union for Conservation of Nature (IUCN)’s 2018 evaluation of the site, few conservation threats exist. Human population density is low, and people are even moving out of the area. This means there will be less exploitation of natural resources and pressure on the environment. Nonetheless, threats like illegal trafficking of cacti, extraction of agave plants and firewood, hunting, overgrazing, forest encroachment, and impacts associated with roads remain ongoing.

Tehuacán-Cuicatlán Valley features relatively undisturbed areas with high conservation value and twenty-two archaeological sites, all embedded within the Tehuacán-Cuicatlán Biosphere Reserve buffer zone. The archaeological remains still maintain their original condition, except for the inevitable effects of weathering over millennia. However, there have been no major disturbances to their physical or spiritual attributes.

Management plans address threats to the area, such as development, and call on coordination with local, national, and international stakeholders to address them. The institutions charged with implementing protective measures for the site are the Ministry of Environment and Natural Resources, the National Commission of Natural Protected Areas, the Federal Attorney General for Environmental Protection, and the National Institute of Anthropology and History.

Significance

Tehuacán-Cuicatlán is known as the cradle of agriculture and irrigation in Mesoamerica, given evidence of early domestication of crops and water management systems. The site’s importance in Mesoamerican history is evidenced by remains found in caves, plant domestication sites, use of wild species, salt ponds, and pottery. Together, these innovations represent the appearance and development of one of the oldest civilizations in the world. Across the valley, evidence of these early technologies demonstrates the constant adaptation of humans to their environment and their ability to overcome challenging environmental conditions.

In addition to its cultural significance, the Tehuacán-Cuicatlán Valley has incredibly high biological diversity. In particular, the valley is home to a remarkable diversity of cacti; in some places, densities of 1,800 cacti per hectare speckle the desert landscape in “cacti forests,” making the valley one of the most unique vistas in the world. The Tehuacán-Cuicatlán Valley is home to eighty-six species of cacti; twenty-0ne of which are found nowhere else in the world.

The site also boasts a high diversity of other plant types, especially yuccas, bromeliads, bursera, and oaks. The site’s thirty-six plant communities feature fifteen different shrublands found nowhere else in the world. More than three thousand species of vascular plants can be found here, 10 percent of which are found exclusively in the valley. It is also a global center for agrobiodiversity and diversification of numerous groups of plants, especially cacti. In addition, the valley is rich in flowering plants. About 70 percent of worldwide floral families are represented here. About 2,700 species can be found within an area of about 3,861 square miles (10,000 square kilometers).

Tehuacán-Cuicatlán also boasts impressively high animal diversity, including mammals, birds, amphibians, and fish, many of which are found nowhere else in the world. The valley is home to one of the world’s highest biodiversity levels of amphibians, reptiles, and birds in dryland. It is located in one of the most important protected areas worldwide when it comes to the conservation of protected species. It is ranked as one of the two most important protected areas in the world for the conservation of seven amphibian and three bird species.

It is also home to a high number of threatened species, like the green macaw. Thirty-eight animal species living in the valley are listed under the International Union for Conservation of Nature (IUCN) Red List. When it comes to land mammals, the valley is one of the richest protected areas in Mexico, with 134 species, two of which are unique to the valley. The area also has 353 bird species, nine of which are only found in Mexico. A whopping 765 species of insects live here as well.

Although known as the cradle of civilization in Mesoamerica, this site remains important to human communities. The valley is home to eight different Indigenous groups including the Nahua, Popoloca, Mazatec, Chinantec, Ixcatec, Cuicatec, and Mixtec. The total population of the valley is around 35,700, with most dependent on agricultural activities for their livelihoods. This includes the collection of wild fruits and seeds, seasonal agriculture and irrigation, raising livestock like goats, cattle and horses, the extraction of stone materials, and forestry. Locals have generated an immense amount of traditional knowledge about the names, uses, and ecological information about nearly 1,600 plant species.

People living here also depend on the vast biodiversity of the region for food. For example, all the species of columnar cacti here can be used for their edible fruits. Some of them even provide edible flower buds and seeds. The fruits are prepared in a number of ways by different groups: the species P. chichipe is dried to produce “pasado” (raisin) fruit, flower buds of N. tetetzo are cooked and prepared with vinegar as conserve, and the fruits from M. geometrizans and M. schenckii are consumed fresh, prepared as ice cream, dried as raisins or mixed with an alcoholic beverage called aguardiente to prepare spirits.

Studies have found that fruits of most columnar cacti species here are integrated into the diet of rural people in different seasons. Selling the fruits in traditional markets also makes these cacti an economic resource for locals. In addition to their food uses, these cacti are also valuable as food for livestock, fuelwood, wood for construction, and live fences. There is evidence that humans have utilized these cacti since the first stages of human occupation in the valley.

Bibliography

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