biosphere reserve in Mexico
The Tehuacán-Cuicatlán Biosphere Reserve is in the Mexican states of Puebla and Oaxaca and a mixed world heritage site.
The area belongs and is located in the Sierra Madre del Sur mountains. It is characterized by its rugged terrain around the broad valleys of Tehuacán and Zapotitlán and the Glen of Cuicatlán.
The importance of Tehuacán-Cuicatlán lies in the great floristic diversity of the area. The predominant flora in this Biosphere Reserve is the xerófita, comprising more than a third of the species detected in the place. It has importance in the presence of one of the few areas of cloud forest that are located in Mexico.
Although designated as a Biosphere Reserve, the area is also of great historical importance. The reason that UNESCO classifies it as a 
UNESCO World Heritage Site rather than listing it only as a biosphere is because several archaeological finds revealed evidence of early crop domestication dating to around 9000 BC as well as having evidence of canals and irrigation improvements to support domesticated agriculture. The National Institute of Anthropology and History (INAH) has no established archaeological sites within the reserve and does not encourage archaeological tourism to the area, though development of such facilities is likely.
For being a desert, this mountainous area is very biodiverse, especially when it comes to different cacti. The biosphere reserve boasts one of the highest concentrations of columnar cacti in the world. There are also more than 300 different bird species and about 85 different reptile species, many of which are endemic to the region. Due to its endemic species, endangered species, and its rare floristic species, the site is an IUCN world biodiversity hotspot.
The climate of the region is warm semi-dry and warm semi-tropical in the region of the Glen Cuicatec with moderate rains scarce in the summer. In the high parts of the mountains it is common to see that the mountains are topped by a thick fog that rarely comes to condense in the form a modest drizzle.