In order to understand and mitigate the long and short-term adverse impacts associated with the destruction or modification of wetlands, the Ramsar Convention emphasises the importance of assessing the status, trends and threats to wetlands. However, in many locations, lack of data is a serious constraint to the effective reporting on wetland status and trends. Conventional data are often lacking in time or space, are of poor quality, or are only available at locations that are not necessarily representative of the wetland ecosystem.
There is a growing awareness that EO data has the potential to provide the information needed for accurate wetland assessments and updating of several data fields on the Ramsar Information Sheet (RIS) including the physical features of the wetland (data field 16); the presence and dominance of particular wetland types (data field 19); as well as factors affecting the ecological character of the wetland (data field 26). Lake Burullus in Egypt is used here as an example to illustrate the practical applications of EO for obtaining such information with a specific focus on using this to update the RIS.
Context and ecological character
Lake Burullus is a shallow, saline lagoon along the Mediterranean coast containing numerous islands and islets connected with the sea by a narrow channel. It provides important wintering, staging and breeding habitat for birds, and has been a designated Ramsar site since 1990. The Lake is connected to the sea at it north-eastern edge through the Burullus inlet. The northern border is separated from the Mediterranean Sea by a strip of land covered with sand bars and dunes. Seven drains and fresh water canals are connected to its eastern, southern and western shores. The lake barriers are sandy and range from 0.4 to 5.5 km in width. Low relief backshore and foredunes characterize the western barrier. The eastern barrier is narrow and backed by coastal barchans dunes. These dunes encroach landward onto a cultivated coastal flat.
Pressures and threats
Major pressures on the wetland include reclamation for agriculture, aquaculture and urbanization. As a consequence the site is subject to the inflow of large amounts of water contaminated with fertilizers and pesticides causing nutrient-enrichment and pollution. In addition, the freshwater inflow from the surrounding land may be declining as result of increasing demands for water for economic purposes, including the expansion of irrigated agriculture. This could affect the salinity and hence the ecological character of the wetland.
Currently there is no systematic way to characterize and monitor threats and impacts on Lake Burullus. There is an immediate need to update the latest available RIS from 1992. The designated Ramsar Administrative Authority in Egypt, the Nature Conservation Sector under the Egyptian Environmental Affairs Agency, has therefore collaborated with the GlobWetland-II (2010-2014), SWOS (2015-2018) and GlobWetland Africa (2015-2018) project to support the Lake Burullus RIS and management planning with EO information about the status and trends in the wetland’s ecological character.
Under GlobWetland Africa the recent status of Lake Burullus was mapped from multi-date Sentinel-2 imagery acquired on the 1st May and 15th of July 2016. Sample sites were identified through visual interpretation of very high-resolution imagery available from Google Earth, combined with a reference from the local land cover/land use database. These datasets were used to train and calibrate a supervised classifier in order to produce a map of the spatial distribution of key wetland types and the surrounding land use (Figure 1 - left). Similarly, and under GlobWetland-II the long-term changes in Lake Burullus were mapped by comparing images acquired by the Landsat mission during the 1970s, the 1990s and the 2000s (Figure 1 - right).