Location and General Description
These mangroves are situated in the western portion of Chiapas, running northwest southwest on the Pacific Coastal Plain, parallel to the vast Sierra Madre de Chiapas. The climate is tropical with abundant summer rains, which make this ecoregion one of the wettest in the state of Chiapas and in Mexico, with 2500-3000 mm of annual rainfall. The coastal plain is composed of clay and sandy sediments, with abundant metamorphic rocks. Most of the area is flat, but some low elevations allow the rivers Vado Ancho, Cintalapa, and Guerrero to continue their route to sea. Soils are of a clay-sand nature, deep with abundant organic matter (Gobierno del Estado de Chiapas & TNC 1993).
Red mangrove (Rhizophora mangle), white mangrove (Laguncularia racemosa), yellow mangrove (R. harrisonii) and black mangrove (Conocarpus erectus) trees, as well as water zapotón (Pachira aquatica) dominate the tree species in this ecoregion. Some fruit trees including Cynometra petusa, chicozapote, fig trees, and guanacaste grow in association with mangrove trees, as do other plant aggregations, including coastal scrub, tule (Typha spp.), coastal dune vegetation, and palm trees (Rzedowsky 1988).
The mangroves on the Pacific Coast of Chiapas have been recognized as some of the tallest mangroves in Mexico, with trees reaching heights of 25 m. (Palacios-Espinosa 1993). They are also home to the unique yellow mangrove tree (Rhizophora harrisonnii), a species that was originally thought to be exclusive to Ecuador and Costa Rica (Palacios-Espinosa 1993). According to CONABIO (1998), the Soconusco area –in which this ecoregion is included, has a high diversity of plant, bird, fish, and crustacean communities.
The most notable wildlife feature of this ecoregion is its avifauna with large resident, winter and migrant populations. This ecoregion’s avifauna is impressive enough to warrant its listing by Stattersfeild et al. (1998) as an endemic bird area. Three restricted range species enter this mangrove ecoregion including the white-bellied chachalaca (Ortalis leucogastra), Pacific parakeet (Aratinga strenua) and giant wren (Campylorhynchus chiapensis) (Stattersfield et al. 1998). Each year, the Pacific coast of Chiapas receives thousands of migrant birds coming from colder regions in Canada and the U.S.A. to spend the winter feeding on the diversity of invertebrates and fish inhabiting the mangroves. Winter residents of this ecoregion include American white pelican (Pelecanus erythrorhynchos), anhinga (Anhinga anhinga), snowy egret (Egretta thula), wood stork (Mycteria americana), blue-winged teal (Anas discors), peregrine falcon (Falco peregrinus), American coot (Fulica americana), plumbeous kite (Ictinia plumbea) and northern shoveller (Anas clypeata) (CONABIO 1998). Year round residents include rare species such as black-collared hawk (Busarellus nigricollis), grey-necked wood-rail (Aramides cajanea), least grebe (Tachybaptus dominicus) and Black-Crowned Night Herons (Nycticorax nycticorax) (CONABIO 1998).
Mammals and reptiles also add to the diversity of this mangrove ecoregion. There are at least three species of crocodile like reptiles including Crocodylus acutus, Crocodylus moreletti and Caimen crocodylus with a subspecies that is endemic to Chiapas, C. crocodylus chiapasius (CONABIO 1998). Additional reptiles represented in this ecoregion are species such as crucilla turtle (Staurotypus salvinii), black turtle (Trachemys scripta gaigae) and yellow-headed turtle (Kinosternon cruentatum). Mammals in the mangroves are not uncommon; however, many mammals utilize the mangrove ecosystem for resources such as food, shelter and to escape from conditions outside of the ecoregion which may be unfavorable. Although according to CONABIO (1998) black-handed spider monkey (Ateles geoffroyi), tayra (Eira barbara), greater grisón (Galictis vittata), ocelot (Leopardus pardalis), nutria (Lutra longicaudis), jaguar (Panthera onca), puma (Puma concolor) and Baird's Tapir (Tapirus bairdii) do live in this ecoregion.
Mangroves have been gradually eliminated due to their potential as sources of wood for human use. There is no information on how well preserved the region is or how intact the habitat remains, but federal protection is being carried out as part of "La Encrucijada" Ecological Reserve (Gobierno del Estado de Chiapas & TNC 1993). Despite many federal protected areas, less than 10% of the state is being protected. The management plan for "La Encrucijada" Ecological Reserve addresses the issues necessary for the protection and preservation of the tallest mangroves in Mexico (Gobierno del Estado de Chiapas & TNC 1993).
Types and Severity of Threats
Dumping of organic and inorganic waste threatens the survival of many aquatic species and others that simply utilize the products of these mangroves. Development both residential and commercial is threatening this ecosystem due to the human population growth as well as tourism, which could displace mangrove communities. Economic and social problems have forced villagers to overexploit animal species through over hunting and collection for the wildlife trade including several mammals, marine species and reptiles such as turtles and iguanas. As a result, these species have acquired endangered status. Immediate management and planning of conservation strategies is required for nearly the entire state of Chiapas. Chiapas is one of the richest and most biologically diverse places in Mexico (Alvarez del Toro 1993) however if agricultural expansion, shrimp farming, freshwater diversion, logging and road construction activities continue to threaten this mangrove ecoregion diversity will suffer (Olson et al. 1996).
Justification of Ecoregion Delineation
Classification and linework for all mangrove ecoregions in Latin America and the Caribbean follow the results of a mangrove ecoregion workshop (1994) and subsequent report (Olson et al. 1996).
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Prepared by: Alejandra Valero and Christine Burdette
Reviewed by: In process