THE IMPORTANCE OF THE WETLANDS
Considering the diversity of plants and birds communities, among other communities, the delta of the Usumacinta-Grijalva rivers must be regarded as one of the most important nature reserve in Mexico and in the world. In the whole Mesoamerican region there are no such big wetlands area as the one located in the states of Tabasco and Campeche. In North America, the Usumacinta-Grijalva delta wetlands are the second most important after those of the Mississippi in the United States. In fact, the Usumacinta is the most important river in all Mexico, speaking of flowing volume of water.
This wetlands area is considered the last frontier- not yet seriously damaged- for winter migration of birds on the American continent and also as the biggest aquatic plants reserve in Mesoamerica. In this area there are some rare plant species which have a high risk of becoming extinct. This area is also considered as the last habitat for the Jaribu stork which has only a few remaining individuals. It is also an important habitat for threaten species such as the alligator, the jaguar, the howling monkey, the white turtle and the manatee.
No real assessment of the biodiversity of this ecological system has been made; it is surely bigger than expected, because existing studies are limited.
The importance of this ecological system has been "in part" recognized by the Mexican government, which has established the Biosphere Reserve of the Wetlands of Centla (BRWC) in Tabasco in 1992 and also the Flora and Fauna Nature Protected Area of Terminos Lagoon (NPTL) in 1994 in Campeche. All together they cover an 10,077 km2 area (2,489,019 acres). According to no reason, the region has been divided into two protected area with different legal status. Besides all, the protection decrees exist only on paper. Five years after the establishment of the Biosphere Reserve, there is no management program yet, and the main field station has been abandoned.
The Mexican government has not carried forward the international agreements it has signed to protect the biodiversity of the wetlands. Among those agreements are the Ramsar Convention for the Protection of Wetlands Internationally Important and specially the Ramsar Practical Guidelines; the Convention on Migratory Birds, the Convention for the Protection of Nature and Wildlife Preservation and also a trilateral agreement signed in march of 1988 between environmental authorities of Mexico, Canada and the United States to protect the wetlands where migratory birds spend the winter.
Both the BRWC and the NPTL are threaten of even more damages due to the daily operation of the installations of PEMEX, the Mexican; the discharges of municipal waste water; the use agrochemicals and the destruction of the mangrove area by agricultural and cattle farming activities.
Among the installations of PEMEX located in BRWC there are 12 producing fields, mainly of gas and one separation station. In spite of the recognition, in the official documents which brought into being the BRWC and NPTL, of the negative impacts of PEMEX activities in these areas, the activities have been going on.
The impacts in the buffer area of BRWC, which represents over 50% of the whole reserve, are even larger and threaten the nucleus zones and the integrity of the whole reserve. In this area the Environmental authorities have allowed not only so-called maintenance installations, but also new explorations.
PEMEX activities have caused serious damage, mainly due to drilling mud which, although it is considered an hazardous waste, is stored in open pits without any lining. The hazardous wastes flow over the pits into the wetlands during the rainy seasons. This situation, very common in the area, violates existing regulations for hazardous wastes management and disposal.
The presence of polyaromatic hydrocarbons (PAHs), and oily residues in the lagoons and rivers, is a clear indicator of the critical situation of the BRWC.