Ria Lagartos mangroves
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Ría Lagartos mangroves
Flamingos at the Ria Lagartos Lagoon. Source: A.H. Karma
The Ría Lagartos mangroves, are found on the northern tip of the Yucatan Peninsula, Mexico, as part of an area comprised of a complex of convergent habitats that include estuaries, coastal lagoons, and sand dunes, which together are considered a wetland of international importance under the RAMSAR Convention. The Ria Lagartos mangroves unit is usually considered an element of the Petenes mangroves. The land area protected in the Ria Lagartos Preserve is 60,347 hectares.
Ecological processes including sea level fluctuation, temperature variation, salinity levels and the influx of freshwater are important to the dynamics of the Ria Lagartos Lagoon. As a primary producer and filtration regime for aquatic nutrients, this mangrove ecoregion occupies a key place in the coastal trophic chain. In addition, the Ria Lagartos Lagoon exchanges is of vital significance for fisheries in the general region.
Rio Lagartos National Park, Yucatan, Mexico (Photograph by Raul Ivan Martinez y Gerardo Ceballos/SEMARNAP) Location and general depiction
The Ría Lagartos mangrove ecoregion streches along the coast on the east end of the Yucatan Peninsula facing Alabama, USA from across the Gulf of Mexico. These mangroves are bounded by calcareous deposits and limestone, which is the major soil formation in the area. The climate is sub-humid with little variation, and there are no relevant topographical features, as the whole area is rather uniform and without notable relief.
Trees of both Red Mangrove (Rhizophora mangle) and Black Mangrove (Avicennia germinans) species, occur throughout the Ria Lagartos ecoregion, with the most striking feature being arboreal vegetation that has adapted to life in saltwater and briny water. Two forest types of mangrove are found in this ecoregion: (1) the pygmy mangrove forest, characterized by plants reaching no more than two meters (m) in height, a mangrove forest type generally found where marine sediments do not supply sufficient nutrients compared to more sheltered mangrove occurrences; and (2) and the fringe mangrove forest, in which trees reach almost ten meters in height, generally dominated by A. germinans and R. mangle. The fringe formation is one exposed to direct tidal wave action, and generally occurs in the immediate intertidal zone. Both mangrove forest types occur in areas that are permanently flooded with various concentrations of saltwater. The pygmy mangrove habitat also contains plants of the Cyperaceae family. The distribution of mangrove trees in this area is often not continuous, but rather interspersed with grasslands and occasional subtropical dry forests.
Biodiversity
Ria Celestun NP, Mexico. Source: Gerardo Ceballos /SEMARNAP The adaptation of mangrove trees to saltwater conditions has produced a unique habitat that enables many aquatic species to survive and reproduce.Compared to other continental areas with the same size, these ecosystems contain a high diversity of flora and fauna. More than 520 species of vascular plants, 333 avian taxa (117 resident, 142 migratory and 14 resident/migratory), and 95 reptile species are found at the site.
Birdlife
Ría Lagartos mangroves are the primary nesting site of the Caribbean Flamingo (Phoenicopterus ruber) in Mexico. Approximately 333 species of aquatic birds also depend on the habitat provided by mangroves and their surroundings for feeding purposes including various cormorants (Phalacrocorax spp.), Wood Stork (Mycteria americana), Boat-billed Heron (Cochlearius cochlearia), white egret (Egretta alba egretta), and snowy egret (Egretta thula). It has been estimated that over 300,000 aquatic birds use Ría Lagartos as migrating points or wintering grounds. The wetlands of these mangroves sustain the largest number of nesting pairs (about 89 percent) of the Caribbean Flamingo population in the entirety of mainland North America.
Fish
The ichthyofauna of the Ria Lagartos area comprises at least 71 species of fish, some of them of considerable commercial value.
Amphibians
There are at least fourteenanuran species found in the Ria Lagartos Lagoon habitat: Gulf Coast Toad (Incilius valliceps); Cane Toad (Rhinella marina); Burrowing Toad (Rhinophrynus dorsalis); Mexican White-lipped Frog (Leptodactylus fragilis); Marbled Treefrog (Trachycephalus venulosus); Mexican Treefrog (Smilisca baudinii); Painted Treefrog (Tlalocohyla picta); Mahogany Treefrog (Tlalocohyla loquax); Yellow Treefrog (Dendropsophus microcephalus); Red-eyed Treefrog (Agalychnis callidryas); Yucatan Casque-headed Treefrog (Triprion petasatus); Northern Sheep Frog (Hypopachus variolosus); Sabinal Frog (Leptodactylus melanonotus); Rio Grande Frog (Lithobates berlandieri). There is a single salamander taxon present here: the Yucatan Salamander (Bolitoglossa yucatana).
Reptiles
Of the 95 reptile taxa found here there are some key special status sea turtles present. Four marine turtle species, two endangered by extinction, breed on the Ria Lagartos foreshores: the Hawksbill Sea Turtle (Eretmochelys imbricata), Loggerhead Sea Turtle (Caretta caretta), Leatherback Sea Turtle (Dermochelys coriacea), and Green Sea Turtle (Chelonia mydas). In particular the beaches at Ria Lagartos Lagoon are a chief nesting ground for the Hawksbill Turtle in all of Mexico.
Mammals
The Ria Lagartos mangroves has recorded more than 55 species of mammals, including endangered species such as the Jaguar (Panthera onca), Ocelot (Felis pardalis) and the Margay (Felis wiedii).
Current status
The area has been included within the Mexican Protected Natural Areas (PNA) network. Ría Lagartos was established as a PNA in 1979, and as a RAMSAR site in 1986. The key protected areas within the reserve are the mangroves, coastal dunes, subtropical forest, and the "Petenes", circular assemblages of trees that form a natural transition from dry to flooded habitats.
Threat scenarios
Mangroves are being continually eliminated due to expansion of villages and even smaller human settlement areas. Although the effects of mangrove tree exploitation are less evident than in some other tropical locations, habitat fragmentation and chemical contamination of water, as well as deforestation of mangrove trees for local uses, pose an enormous risk to the survival of the habitat and its ecological processes. The complexity of mangroves as a habitat, and their variety of ecological relationships, are in danger of deterioration due to habitat fragmentation and intensive exploitation. The number of fish and invertebrates in the mangroves has declined, and the Jabiru (Jabiru mycteria) has already disappeared from the reserve, although it is considered a species at risk of extinction. Surface hydrology in this mangrove ecoregion has been modifiedby human activites, which may significantly alter the natural salinity regime, causing major disturbance, and ultimately extinction of animal and plant communities.
There are four human settlements within the Ría Lagartos Biosphere Reserve: San Felipe, Río Lagartos, Las Coloradas and El Cuyo, with 1610, 2844, 1300, and 1162 inhabitants respectively. Expansion of these settlements, along with concomitant salt exploitation, wood gathering and farming by indigenous peoples form significant threats to the ecoregion. Furthermore, demand for tourism expansion also poses threats.
Justification of Ecoregion Delineation
Classification and linework for all mangrove ecoregions in Latin America and the Caribbean follow the results of the 1994 Washington DC mangrove ecoregion workshop and subsequent report.
Further Reading
- Arizmendi, C. y Márquez-Valdelamar, L. 2000. Areas de Importancia para la Conservación de las Aves en México. 440 pp. Fondo Mexicano para la Conservación de la Naturaleza, México.
- Ecoregional Workshop: A Conservation Assessment of Mangrove Ecoregions of Latin America and the Caribbean. 1994. Washington D.C., World Wildlife Fund.
- S. Frazier, editor. 1999. A directory of wetlands of international importance (designated under the RAMSAR Convention). Compiled by Wetlands International. ISBN: 2940073171
- INE-SEMARNAP. 1999. Programa de Manejo Reserva de la Biosfera Ría Lagartos. 203 pp. SEMARNAP, México.
- Mittermeier, R.A.; Myers, N; Robles-Gil, P.; y Goetsch, C. 1999. Biodiversidad Amenazada: Las ecorregiones terrestres prioritarias del mundo. CEMEX, y SIERRA MADRE, México.
- D.M. Olson, E. Dinerstein, G. Cintrón, and P. Iolster. 1996. A conservation assessment of mangrove ecosystems of Latin America and the Caribbean. Final report for The Ford Foundation. World Wildlife Fund, Washington, D.C.
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