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Despite a scarcity of precipitation,
hundreds of springs rise from the valley floor, creating an
intricate hydrologic system that includes a variety of
aquatic habitats including pools (pozas), marshes, flowing
rivers, barial or saline lakes (lagunas or playas), and
wetlands. This variety of habitat maintains a highly diverse
flora -- 860 species in 456 genera from 114 families
(Pinkava 1978, 1987). The valley has maintained a hospitable
and stable environment during times of climatic flux
allowing this diverse flora to persist.
Roughly 80 springs with flows of 4 meters
second have been reported (Minckley 1969) while flows from
numerous other springs average 1 meter per second. The
abundance of surface water makes the basin a unique
environment in otherwise arid lands.
Rio Mesquites winds through the
valley floor. The white in the foreground is a
"salina", a salt pan caused from evaporation of
water. (Photo from National Geographic Magazine,
October 1995)
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In addition, the high concentration of
minerals in the water support an unusual assemblage of
organisms, including stromatolites which appeared 300
million years ago. It is believed that both the aquatic and
terrestrial habitats of the basin have been relatively
unchanged throughout the Quaternary, regardless of
alterations in regional climate (Meyer 1973).
The basin was explored by biologists for the
first time in the late 1930s during U.S. - Mexico field
surveys designed to create Sierra del Carmen-Chisos
Mountains (Big Bend) International Park (Minckley 1992).
Twenty years later sampling of the area resumed. It was then
that the magnitude and diversity of the biota was realized.
More than 50 taxa, including cacti and other vascular
plants, invertebrates such as snails, crustaceans and
scorpions, fishes and reptiles are known no where else but
this small 1,200 square km valley. Geologic continuity
coupled with relative ecological stability, at least through
the Holocene, has allowed this highly endemic, relict biota
to develop and persist (Meyer 1973).
Due to the abundance and diversity of
surficial waters the valley supports atypical as well as
typical vegetation of the Chihuahuan desert. Plant
communities include grasslands, aquatic plants, sedges and
marshes, gypsum dune assemblages, desert scrub, and
chaparral (Pinkava 1978). Common Chihuahuan desert species
include creosote (Larrea tridentata), tarbush (Flourensia
cernua), and ocotillo (Fouquieria splendens) (Pinkava 1978,
Calegari 1997).
Evidence of human inhabitants of the basin
such as arrowheads, bows, woven goods and human bones date
back some 10,000 years (Calegari 1997). However, little is
known about these early peoples. Cuatro Ciénegas
became a stop on a well traveled trade route in the 16th
century (Calegari 1997). Settlement activity occurred
throughout the 1600s and in 1674 a Spanish mission was built
in the basin. These early Spanish settlers built the first
canals through the basin.
Despite the settlement activity throughout
the 1600s and 1700s, the town of Cuatro Ciénegas de
Carranza was not officially founded until 1800 (Calegari
1997). Ranching and agriculture were the main economies of
the basin throughout the 19th century, and mining became an
important part of the economy in the early part of this
century. Ranching and agriculture continue today, and within
the past 30 years gypsum mining has become a principle
industry. A salt extracting plant and a Fruit of the Loom
clothing plant both opened in 1996 (Calegari 1997).
In 1994, the Mexican government declared the
valley a Natural Protected Area (NPA) in an effort to
conserve the biotic resources while at the same time
providing residents opportunities in sustainable development
(Calegari 1997).
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