NEWS
Floating wetlands: creating
habitat and cleaning water
Small steps to making a big difference
Dale Wright
Current Address: IBA Conservation Implementation Manager, BirdLife South Africa
Reprinted From: http://bit.ly/2FpS21b
T
he term “floating wetlands” might
at first conjure up an image of large
swathes of dense papyrus reeds
bobbing up and down in the Okavango
Delta. However, these are floating wet-
lands of a different, slightly smaller kind,
popping up on farm dams in the West-
ern Cape. In early 2015, BirdLife South
Africa and NCC Environmental Services,
with funding from the Table Mountain
Fund, initiated a pilot project to de-
velop mechanisms for improving water
bird habitat on farm dams. After spend-
ing much time traversing the backroads
of the region we noticed that very often
these dams appeared sterile, providing
very little refuge for birds and biodiver-
sity. But did it need to be that way? Or
was it possible to turn these isolated,
artificial water bodies into havens for
biodiversity?
Our initial investigations revealed the
obvious fact that these are working
dams, whose water levels fluctuate an-
nually as they are filled and subsequent-
ly drained for irrigation. The changes in
water level prevent vegetation from es-
tablishing and surviving. So, the habitat
we envisaged would need to rise and
fall with the water levels…and thus were
born the floating wetlands.
The project set about identifying will-
ing partners who would assist in testing
the various designs for these floating
wetlands. The structures needed to be
sturdy enough to carry wetland plants
and substrate, but easy to assemble
from materials which you might find
around the farm. The other critical issue
we thought to address is the excess nu-
trients which often accumulate in water
bodies in agricultural landscapes, be-
cause of fertilizers and other chemicals.
Wetlands are known to act as water pu-
rification plants, extracting excess nutri-
ents and ultimately cleaning water. We
realised this would be difficult to test in
the landscape, and fortunately a Stel-
lenbosch University student joined the
project, studying the ability of different
wetland plants to absorb nutrients from
Grassroots
Vol 18
No 4
polluted water. The results were en-
couraging, suggesting that those spe-
cies which we might encourage farmers
to plant on the floating wetlands, could
perform this task.
for supporting this project, and all our
project partners and landowners who
helped gather the information neces-
sary to compile the “Floating Wetlands”
Guideline
After much trial and error an optimal
design for the floating wetland was de-
veloped, and the project team has writ-
ten up a guideline for their construction.
This guideline document also includes
information on the common groups of
water birds a farmer might encounter
and their basic ecology. Additional ap-
proaches to creating habitat for water
birds and other biodiversity are also in-
cluded. Allowing rank vegetation reed
beds to develop in areas, perhaps creat-
ing shallow mud flats in others, or add-
ing some large tree branches as roost-
ing structures, can all enhance a dam for
water birds. The guideline is filled with
useful information for landowners inter-
ested in turning their dam into a haven
for biodiversity. It can be freely down-
loaded from our website (http://bit.
ly/2FsKWci and http://bit.ly/2OOEdss),
and we encourage readers to share the
guideline far and wide.
Watching Red-knobbed Coots begin to
build their nests on the mini-wetlands,
and various species of dragon flies and
frogs returning to a dam, otherwise de-
void of life, was very encouraging. Ulti-
mately, by providing nature with even
the smallest of homes, biodiversity can
be given a chance to flourish. We would
like to thank the Table Mountain Fund
Figure 1 - 3: Examples of floating wetlands that landowners can use to turn their
dams into a haven for biodiversity.
December 2018
22