ABSTRACT

Throughout the world, the integrity of the epicontinental freshwater systems and their biological diversity are being increasingly threatened by human activities. The great variety of these activities lead to frequent conflicts among users and species. Water quality deterioration and depletion of available surface and groundwater resources points out that the epicontinental waters are not bottomless. The social and economic welfare of a country relays, on great extent, in the capacity of the epicontinental freshwater ecosystems to supply its services; hence the importance to maintain its integrity through a rational and sustainable way.

Therefore, the need to revise the status of the information on the diversity and biological value of the drainage basins arises, as well as to evaluate the direct and indirect threats to the resources and the potential for their adequate conservation and management.

With this background, in may of 1998, the National Commission for the Knowledge and Use of Biodiversity (CONABIO) initiated the Programa de Regiones Hidrológicas Prioritarias with the purpose of developing a reference framework to contribute to the conservation and sustainable management of the epicontinental waters environments. This programme is part of a set of strategies established by the CONABIO to promote, at a national level, the knowledge, use and conservation of the biological diversity of Mexico.

Among the activities directed to fulfill this task, the CONABIO organised two workshops on hidrological priority regions, from 20-23 April and from 25-26 May of 1998, to define regions regarding freshwater resources as priority considering biodiversity. The workshops gathered 45 academic, govenment and non-governmental organisation specialists to diagnose freshwater environments and select areas with respect to high biological richness, the degree of general knowledge or the lack of information, the actual and potential use, the actual and potential negative impacts on biodiversity and the environmental services.

With this information, maps of the Mexican territory were made for the areas of top priority concerning biodiversity, use of resources, lack of information and potential for conservation. Likewise, technical file card for each area with information on limnology, geology/edaphology, water resources and biodiversity, as well as on the use of resources, economic aspects and conflicts and recommendations on research, conservation and use were obtained.

Of 110 identified drainage basins of top priority considering biodiversity, 82 correspond to areas in use and 75 are biologically rich areas with potential for conservation; within these two categories, 75 are threatened in some way. Also 29 areas were identified that are biologically important but for which there is not enough scientific information on biodiversity.

Conflicts between sectors were identified. Aspects such as excessive exploitation of underground and surface waters stand out since they cause a strong decrease in the available water resources, saline intrusion, desertification and alteration of the aquatic systems. Pollution of underground and surface waters, specially by domestic, industrial, agricultural and mining waste waters diminish the water quality leading to eutrophication and alteration of aquatic systems. The accelerated erosion process caused by activities that modify the landscape such as conversion and modification of natural habitats to agricultural, ranching, forestry and industrial expansion as well as population growth lead to deforestation, basin alteration, damming and channeling, dessication and filling of wetlands, soil loss and fires. Finally, the introduction of exotic species to the freshwater ecosystems results in the consequent replacement of native species and lost of biological diversity.

Also and as part of the Programa de Regiones Hidrológicas Prioritarias, the CONABIO issued the book "Aguas continentales y diversidad biológica de México" which is a synthesis of the actual situation of the water resources associated to areas of top priority considering biodiversity. Conflicts and efforts for conservation and management are considered, as well as the scientific knowledge that has been achieved for these regions. This framework is directed to decision makers and to agencies that are related with the establishment of priorities in the management and sustainable use of the Mexican freshwater ecosystems whether for conservation, exploitation, rehabilitation or restoration.

Regiones terrestres prioritarias | Regiones marinas prioritarias | Regiones hidrológicas prioritarias | Áreas de Importancia para la Conservación de las Aves (AICAS)

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Dirección Técnica de Análisis y Prioridades