SE AGRASS ARE AL E XTENT
S1 3
What
What Is It?
BENCHMARK
Seagrass areal extent is a measure of the area (e.g.,
No net decrease in the extent of
No
hectares or km2) covered by seagrasses. Extensive
seagrass
seagrass from current levels.
seagrass beds are found throughout the MAR on most
shallow platforms (approximately < 15 m).
TA R G E T
No
No decrease in extent, or restoration to
Why Do We Measure It?
Why
1990
1990 levels.
Seagrasses are highly productive, faunally rich
RED FL AG
and ecologically important ecosystems that often
act as a transitional zone between mangrove and
More than a 5% reduction in area in
More
coral reef communities. Seagrasses provide critical
any subregion's annual or biennial
nursery and breeding habitat for commercial fish and
assessment, compared to that
invertebrates, help stabilize sediments, reduce beach
subregion's
subregion's previous survey.
erosion and promote water clarity. Productivity is the
main process of concern. Overall extent, density and
diversity (including the epiphytic community) are the
primary structural components of health.
How Do We Measure It?
Measuring the areal extent of seagrass beds indicates
Remote sensing (by satellite or aircraft) can be used
how much of this critical habitat is available. When
to estimate the areal extent of seagrasses, in a
measurements are available for more than one point
process similar to the one used for coral reefs and
in time, we can track how much valuable seagrass
mangroves.
habitat has been lost or gained.
Seagrasses in the MAR region have been damaged
by dredging operations, prop scars and poor water
quality.
Melanie McField / WWF
42