Flora
Biodiversity within Pantanos de Centla has not been completely documented. The studies completed, however, do show that Pantanos de Centla is biologically rich and an important conservation site. Flora within the reserve responds to the distribution of water, geologic formations, soil type, and climatic conditions. Several studies have registered 569 plant species, from 118 families, grouped in eight major associations: (1) aquatic plant communities that occupy 68.1% of the reserve; (2) medium semi-evergreen forests dominated by black olive (Bucida buceras) that cover 6.4%; (3) low semi-evergreen forest of logwood (Haematoxylon campechianum) covering 0.3%; (4) mangroves covering 2% of the reserve; (5) matorral of Aztec rosewood (Dalbergia brownii) covering 1.8%; associations of (6) paurotis palm (Acoelorraphe wrightii) and Texas palm (Sabal mexicana); (7) riparian vegetation covering 5.8%; and (8) crops and pasture 15.6% (Lot y Novelo, 1988; Lopez-Portillo, 1982, INE, 1997; Sol et al. 1993).
The aquatic communities are subdivided into three major vegetation types:
1. Emergent aquatic vegetation Characterized by pure stands of cattails (Typha latifolia), which generally grow between 1 to 3 m tall, sawgrass (Cladium jamaicense) and jointed flat sedge (Cyperus articulatus). Within the reserve, this plant community is impacted by the expansion of agricultural activities, water retention, and wildfires;
2. Floating aquatic vegetation This type of vegetation is concentrated in boggy lake environments where it exists with cattails. Species include: water hyacinth (Eichornia crassipes), common duckweed (Lemna minor), dotleaf waterlily (Nymphaea ampla, N. odorata) and water snowflake (Nymphoides humboldtiana), among others;
3. Submerged aquatic vegetation The primary species are coontails (Ceratophyllum demersum) spineless hornwort, (C. echinatum) and bladderwoat (Utricularia sp.) and they are found in the swamps and marshes. This type of vegetation is the least studied within the reserve, and it seems to be diminishing (Lot y Novelo 1988; Sol et al. 1993).
Fauna
It is estimated that the reserve is habitat for 255 bird species, 104 mammal species, 68 reptile species, 52 fish species and 27 amphibian species (INE, 2000). All terrestrial vertebrates are represented in the reserve, thanks to the range of ecosystems. Focusing on the birds, there are both residents and migratory species, as well as aquatic and terrestrial species. Among the birds, the jaribu (Jabiru mycteria), the wood stork (Mycteria americana), Muscovy duck (Cairina moschata), peregrine falcon (Falco peregrinus) and the osprey (Pandion haliaetus) are found within the reserve (Correa y luthin, 1988; Martínez,1988; Brazda, 1998; Ogden et al.1988; Arriaga et al. 2000; Berlanga et al. 2001).
Migratory bird resting in the reserve
Among the mammals, there are West Indian manatees (Trichechus manatus), the paca (Agouti paca), white-tailed deer (Odocoileus virginianus), jaguar (Panthera onca), ocelot (Leopardus pardalis), mantled howler monkey (Alouatta palliata), among others. These are hunted mostly when the water level of the river rises because the animals migrate to the higher elevated zones to avoid the floods (Álvarez et al. 1988; INE, 2000.).
Different species of fish are found in the various aquatic habitats, the type of species usually depends on the salinity of the water body. There are also resident fish species and migratory fish species. Commercially important species include snook (Centropomus sp.), cichlids (Cichlasoma fenestratum, C. urophtalmus, Petenia splendida, Tilapia sp.) and the tropical gar (Atractosteus tropicus) (Chávez et al. 1988).
Reptiles in the reserve include the Central American river turtle (Dermatemys mawii), white-lipped mud turtle (Kinosternon leucostomum), red eared slider (Pseudemys scripta), Mexican cross-breasted turtle (Staurotypus triporcatus), snapping turtle (Chelydra serpentina), iguana (Iguana iguana), black iguana (Ctenosaura similis), furrowed wood turtle (Rhinoclemmys areolata) and Morelet's crocodile (Crocodylus moreletii). There are also snakes, such as the Mexican vine snake (Oxybelis aeneus) and fer-de-lance (Bothrops asper) (Cabrera, 1988; Plata, 2002; Arriaga et al. 2000; Mazotti, 1988).
The amphibians are represented by a large diversity of frogs and toads, including Rhinophrynus dorsalis, Bufo horribilis, B. valliceps, Rana pipiens, and R. Palmipes.
Among the crustaceans are freshwater prawns (Macrobrachium acanthurus) and big claw river shrimp (M. carcinus) that are found in freshwater; blue crabs (Callinectes spp) and fiddler crabs (Uca spp) are found in the estuaries (either freshwater or marine); and white shrimp (Penaeus setiferus) in estuary and marine environments as well as coastal lagoons where it spends part of its life. Species of commercial value and ones that are intensely harvested include the white shrimp and freshwater prawns. These species are of great economic importance for the region (INE, 2000).
Fiddler crab (Uca spp), photo: Juan C. Bravo
Fauna of the reserve represent a source of protein for the locals. Although no studies have been completed to determine the populations of flora or fauna within the reserve, comparing the various studies with the Official Mexican Norms list NOM-059-ECOL-2001 (DOF 2001), it appears that 199 species are threatened or vulnerable because of habitat loss or over harvesting.
Photo: Juan C. Bravo
