UB ERI Conducts Validation of the 2010 Mangrove Cover Map for Belize
During the months of April and May 2011, the ERI along with local partners, the Southern Environmental Association (SEA), Toledo Institute for Development and Environment (TIDE), Wild Tracks and Sarteneja Alliance for Conservation and Development (SACD) worked in an effort to complete the validation of the 2010 mapping study on the “Identification of Threatened and Resilient Mangroves in Belize” published by the Water Center for the Humid Tropics of Latin America and the Caribbean (CATHALAC) in collaboration the World Wildlife Fund (WWF). The mapping was done using remote sensing data in order to assess the extent of mangrove habitats for the period 1980 to 2010 and to gauge any variance in mangrove coverage from 1980-2010. Validation is a standard procedure for maps that are developed using remote sensing imagery, to determine if the level of accuracy is sufficient enough for the map to be used. The primary component of validation was the ground-truthing, which is basically a process that involves the work of field technicians, tasked with going out and gathering data on the actual location, type and extent of mangroves in order to prove or disprove the accuracy of the map. Ground-truthing was conducted for Turneffe and Belize City/Drowned Cayes by ERI, SACD and Wildtracks ground truthed Corozal Bay/Sarteneja, while SEA and TIDE took on the ground truthing work for Placencia and Port Honduras respectively.
The technical report on the validation of the 2010 Belize mangrove cover map has now been completed through the efforts of Dr. Leandra Cho-Ricketts of the ERI and Mr. Emil Cherrington of CATHALAC. According to the results gathered from the validation, the 2010 map was 90.7% accurate with an 89.6% overall class accuracy, errors of commission (non-mangrove areas erroneously mapped as mangrove) and omission (mangrove erroneously mapped as non-mangrove) were at 34% and 25% respectively for non-mangroves. The errors can be attributed to the use of the change detection technique and revisions must be made in the future to account for such errors. The results of the mangrove cover validation study were presented on the 31st October 2011 at a workshop attended by various co-managers and non-governmental organizations (NGOs). This type of work can be used in the management of the mangrove ecosystems of Belize to aid in the approvals of mangrove clearance applications and development applications through the EIA process. The validated map will serve as an important resource to NGO's, protected areas managers and associated government agencies.