Coahuila Desert Biodiversity: What Lives Here

The semi-desert around Ex-Hacienda Amargos, in the Paredón valley, is part of the Chihuahuan Desert: the largest desert in North America and the second most biologically diverse in the world, covering an area of roughly 505,000 km² (Villarreal-Quintanilla et al., Acta Botánica Mexicana, 2017) [1]. Coahuila is the state that holds the largest share of its endemic species: 31.15% of the total recorded [1]. This is not an empty landscape — it's one of the richest arid ecosystems on the planet.

Key facts

• The Chihuahuan Desert covers about 505,000 km² and is the largest in North America and the second most biodiverse in the world (Acta Botánica Mexicana, 2017) [1].
• It holds the richest cactus assemblage on the planet: Cactaceae and Asteraceae alone add up to 247 endemic species [1].
• Cuatrociénegas (over 84,000 hectares) and Maderas del Carmen (208,381 hectares) were both decreed federal protected areas on November 7, 1994 (SEMARNAT; DOF) [2][3].
• In the Paredón aquifer area, where Amargos sits, the climate is semi-warm arid: 256.8 mm of rain and 20.2°C mean annual temperature (ten weather stations, 1981–2010), almost all of it falling in summer (CONAGUA, 2024) [5].
• The 1994 decree named Maderas del Carmen a monarch butterfly corridor, a nesting ground for 73 bird species, and a refuge for species then considered endangered, such as the black bear and the golden eagle (DOF, 1994) [2].

Why is the Coahuila desert so biodiverse?

The Chihuahuan Desert began forming about five million years ago, in the Pliocene [1]. Its elevation ranges from 1,000 to 3,050 meters above sea level, with an annual temperature range of 5.5 to 35°C [1]. That combination of elevation, geographic isolation and climate shifts over the past 10,000 years explains, according to the study's authors, why so many species here exist nowhere else [1].

How many endemic species are there, and which stand out?

The study identified 826 endemic or quasi-endemic taxa — 24.87% of the desert's flora — of which 671 are endemic species [1]. Four families account for the largest share of those species:

Source: Villarreal-Quintanilla et al., Acta Botánica Mexicana, 2017 [1]. Those four families "together account for 46.2% of the total" (translation) [1].

Cactuses are the richest group: Coryphantha (24 taxa), Mammillaria (15) and Turbinicarpus (15) hold the most range-restricted species, and nine genera — among them Cumarinia and Henricksonia — occur nowhere else [1]. Xerophytic scrub (matorral xerófilo) is the vegetation type with the most range-restricted species [1].

Where is this desert protected in Coahuila?

The federal decree creating Maderas del Carmen describes the area as a site with "ecosystems representative of the Coahuila desert" (DOF, November 7, 1994; translation) [2]. That same day, Cuatrociénegas and Maderas del Carmen were both decreed federal protected areas:

According to SEMARNAT, Cuatrociénegas is "the most important wetland within the Chihuahuan Desert and one of the most important in Mexico" (translation), with springs where the Coahuila box turtle (Terrapene coahuila) and the Cuatrociénegas cichlid (Herichthys minckleyi) survive [3][4].

What animals live here, and where are they protected?

The 1994 decree recorded in the Maderas del Carmen mountains species then considered endangered — black bear, peregrine falcon, golden eagle and white-tailed deer — and described the area as a monarch butterfly migration corridor and a nesting ground for 73 bird species [2]. In the open semi-desert around Paredón, low light pollution is another reason for astrotourism in the region.

What happens in the desert when it rains?

In the Paredón aquifer area rainfall is mostly a summer event: only 5 to 10% falls in winter (CONAGUA, 2024) [5]. In arid zones, even during the rainy season, periods of 19 to 25 days without moisture between light showers of 8 to 10 mm have been reported, according to literature cited by a germination study of Chihuahuan Desert grasses [6]. In that study, half of the species germinated fast (at least half their seeds within three days of moisture) and the other half at a medium pace; none were slow to germinate, though such species tend to keep seed banks in the soil [6] — the same careful water management that building here demands.

How does a rural community coexist with this ecosystem?

In a desert with so many range-restricted species, how the land is occupied matters as much as how much gets built: low density, native vegetation and respected natural corridors make the difference between coexisting with the desert and replacing it. You can see how the land is laid out in the Ex-Hacienda Amargos project and its masterplan.