· Born on the Mother Mountain
· Special Features
· Did You Know?
· Wild Side
· Cause for Concern
· Looking Ahead

Global 200 Snapshot

Many of the aquatic species, particularly the fish, amphibians, and invertebrates that inhabit the lakes and streams of this ecoregion, are endemic. Fish species radiations have occurred in several lakes here.  

Born on the Mother Mountain

Throughout Mexico runs the Sierra Madre, or "Mother Mountain," a long and mighty chain of peaks and plateaus. Nestled among them are numerous freshwater lakes, thermal (hot) springs, and streams that are home to many different species. In addition, the Aguascalientes warm-water aquifer and its associated underground aquatic life underlie portions of the ecoregion.

Special Features

The peaks of the Sierra Madre can reach 10,000 feet (3,000 m) high, while its gorges can be 1,500 feet (450 m) deep. Between these ups and downs lie many different kinds of lakes, including Chapala, Mexico's largest, and Catemaco Lake in the crater of an old volcano. Many of the lakes in this region are endorheic, meaning that they have no connection to the sea.

	This region is so hot and dry that nearly 80 percent of the water in the Lerma River evaporates before reaching Lake Chapala.

Wild Side

Many unusual amphibian and invertebrate species live here, and several fish species radiations have occurred in several lakes. Species include numerous endemic livebearers, splitfins, silversides, pupfishes, cichlids, and characids. Many native fish get their names from the only body of water where they are found, such as the Lerma chub, Chapala chub, and Potosí pupfish. Among the numerous fish species that are found only in this ecoregion are the Mexican brook lamprey, leopard splitfin, bagre catfish, flatjaw minnow, black lyre, graceful priapella, and scowling silverside. Endemic amphibians include frogs such as Rana megapoda and R. montezumae. Freshwater habitats also support distinctive and endemic invertebrates, including La Medialuna crayfish and La Medialuna shrimp.

Cause for Concern

The freshwater species of this mostly dry region must compete with agriculture and growing human populations for the limited water supply. Of great concern is the tapping of aquifers (underground water reserves), which threatens the survival of several fish that live in springs. Water withdrawals and diversions for agriculture, combined with pollution from industrial waste, agriculture, and urbanization, threaten the quality and quantity of water available to the freshwater animals and plants of this ecoregion. Invasive aquatic plants (e.g., water hyacinth and introduced nonnative fish such as blue tilapia) could cause the decline of native species.

Looking Ahead

Check back soon for more about the conservation of this ecoregion.