Due to the requirement for reliable information regarding the extent and distribution of the mangroves in Mexico, as well as the need to identify the processes affecting these ecosystems, CONABIO initiated the program “Mangroves of Mexico: current condition and establishment of a long term monitoring program”. The results of this program will be useful for appropriate definition of public policy and for decision making with respect to conservation, management and ecological restoration of the mangroves of Mexico.
Program “Mangroves of Mexico: current condition and establishment of a long term monitoring program”
National Inventory of Mangroves: coverage and distribution (1st stage)
From May 2006 to September 2008, CONABIO, with the participation of various institutions carried out the first stage of this program in which it was sought to establish baselines of the mangroves in Mexico. The most important results of this first stage are:
The procedure for estimating the coverage and distribution of mangrove in Mexico is based on the digital analysis of SPOT satellite images, taken mainly during the period 2005-2006 (82%), and on fieldwork. Conventional methods of non-supervised classification were used, the results of which were revised, and corrected when necessary by visual interpretation. Thematic maps at the national scale were subjected to Lambert conformal conic projection. In order to optimize classification results, additional information was utilized throughout the process, in the form of orthophotographs from the National Institute of Statistics, Geography and Information (INEGI, for its Spanish acronym), Landsat satellite images, Digital Elevation Models, land-use and land-cover maps from INEGI and the National Forestry Inventory (INF, for its Spanish acronym), as well as other data provided by various research institutions.
The area of mangrove was estimated to be of 770,057 hectares, at a scale of 1:50,000 (map). The Yucatan Peninsula is the region with the greatest percentage of this total (55%), while the Central Pacific has the least area of mangrove (0.9%).
The cartographic accuracy of the distribution map of the mangroves of Mexico was evaluated with low altitude flights conducted by navy helicopters. In this way, more than 97,000 vertical and panoramic high resolution photographs were obtained, which allowed the validation of the mangrove map. A total of 5,744 photographs were used as records of the presence/absence of mangroves. These photographs were selected, revised and validated by regional experts from all over the country. The global accuracy of the map of distribution of mangroves in Mexico was calculated at 90.5%.