Abstract:
For the first progress reporting on the Sustainable Development Goal sub-indicator 6.6.1a in 2020,
the South African and global statistics related to wetlands were compared. Firstly, in terms of the total
wetland extent, the South African National Wetland Map version 5 (NWM5) represented 87% more
inland, surface aquatic ecosystems than the Global Surface Water (GSW) product. More than half of the
lacustrine systems and none of the palustrine and arid systems in NWM5 are represented in the GSW
layer. Secondly, in terms of changes in the extent of wetlands, both the global and South African statistics
showed a decreasing trend in the spatial extent of surface aquatic ecosystems in South Africa. These
trends should be further investigated against systematic assessments of decadal drought periods. The
hydroperiod information (permanent, seasonal and ephemeral inundation periods) of the GSW products
show that South African lacustrine wetlands do not have a single dominant class (≥70% of the extent of
a polygon) of inundation, but consist of a mosaic of these classes.
SIGNIFICANCE :
• The South African National Wetlands Map version 5 represents 87% more of the extent of lacustrine,
palustrine and arid wetlands than the Global Surface Water products that are used for progress reporting
on the Sustainable Development Goal sub-indicator 6.6.1a.
• South African and global statistics suggest a decline in the extent of lacustrine wetlands, although a
systematic comparison with decadal drought periods is required to confirm these trends.
• South African lacustrine wetlands consist of a mosaic of hydroperiod classes (permanent, seasonal
and ephemeral inun
