de los Tuxtlas
by Lindsay Elms
The Sierra de Los Tuxtlas (Tuxtlas Mountains) are a volcanic belt and mountain range along the southeastern Veracruz Gulf coast in Eastern Mexico. The Los Tuxtlas Biosphere Reserve (Biósfera Los Tuxtlas) includes the coastal and higher elevations of the Sierra de Los Tuxtlas.
The volcanic mountains were used as a basalt source by the Olmec culture during the Early Formative period (1500 BCE to about 400 BCE). Quarried basalt was transported by raft through a network of rivers, to sites in the Olmec heartland for use in creating monuments, including colossal heads.
this range include Volcano Santa Marta and Volcano San Martín Tuxtla
(1650m). San Martín Tuxtla is the only recently active volcano
in the belt, erupting in 1664 and again in May 1793. It is a broad alkaline
shield volcano with a one kilometre wide summit and a crater that is 150
metres deep. The 1793 eruption occurred from two cinder cones in the summit
crater and produced widespread ashfall and lava flows that extended 3.5
kilometres down the northeast flank. Hundreds of smaller cinder cones
are prevalent throughout the Sierra. Other extinct volcanoes include San
Martin Pajapan (1160m) and Cerro El Vigia (800m).
The upper flanks of the San Martín Tuxtla and Santa Marta volcanoes are covered with the Neotropical Sierra de los Tuxtlas tropical rainforest eco-region of the tropical and subtropical moist broadleaf forests Biome. The lower portions are covered with stunted pastures and grasslands.
The government started protecting the Neotropical moist forest in the region of Los Tuxtlas in 1979 when 5,000 hectares around the San Martín Volcano were declared a protected forest and a wildlife refuge. In 1982, this protected area was expanded to 20,000 hectares and classified as Special Biosphere Reserve. Another region in Los Tuxtlas, the Sierra Santa Marta, was declared a protected forest and wildlife refuge in 1980 with an area of 20,000 hectares and re-classified two years later as Special Biosphere Reserve. In 1998, the two reserves were combined to create the Los Tuxtlas Biosphere Reserve.
This region is characterized by its notable diversity of plant and animal life and is a refuge for many rare and threatened species that have been displaced from other areas of Mexico, including 19 endangered mammals. The region boasts the highest bird diversity in Mexico in terms of comparable area. Los Tuxtlas is also the northern geographic limit of the moist Neotropical forest in North America. The Los Tuxtlas ecosystem is fundamental to the regions rainwater retention and provides the main water source for important surrounding cities such as Coatzacoalcos, Minatitlán, Acayucan, San Andrés Tuxtla and Catemaco.
Due to its geographic location, wide altitudinal range, mountain slopes, and its position with respect to the wet winds of the Gulf of Mexico, the Los Tuxtlas region has great biodiversity. Nine different types of vegetation have been identified in the area.
is one of the most-studied protected areas in Latin America, and as a
result, tropical deforestation has been well documented. Despite several
studies and investigations by national and international academic institutions,
and regional government programs for social development, the region's
high rates of deforestation, illegal commerce of wild animals, and water
pollution have not slowed in recent years. The regions agricultural and
livestock activities have caused the loss of more than 85% of the original
forest cover. Since the area's designation as a biosphere reserve in 1998,
the government has implemented a series of programs and actions to promote
sustainable development projects to diversify the local means of production
and not damage the environment. Despite these efforts to protect the reserve's
biological integrity, Los Tuxtlas is considered critically threatened.