NEWS
In a flood (of tears) for the
lost riparian woodlands of the
Lowveld
Current Address: SAEON Ndlovu Node
Reprinted From: http://bit.ly/32Qt55v
Joshua Weiss and Dave Thompson
T
he rivers of the Lowveld are the
lifeblood of the landscape, trans-
porting water, sediments and nu-
trients from the escarpment and sur-
rounding landscape, which become the
important resources that sustain critical
aquatic and riparian habitats.
Riparian vegetation differs markedly
from upland areas, particularly in winter,
with brown savanna giving way to lush,
year-round greenery.
Magnificent jackalberry (Diospyros mis-
peliformis), sycamore fig (Ficus syca-
morus) and nyala tree (Xanthacercus
zambeziaca) specimens, to name a few,
are supported in this transition zone
between aquatic and savanna realms.
Plants here are able to withstand the
high water table and accumulation of
nutrients associated with riverbanks.
Indeed, many of the Lowveld’s riparian
woodlands are so unique that they are
classified as distinct vegetation units
(i.e. Subtropical Alluvial Forest and
Lowveld Riverine Forest).
These riparian zones range from as lit-
tle as 10 m in width to over 250 m wide
along some parts of the Sabie and Lu-
vuvhu Rivers in the Kruger National Park
(KNP). This riparian vegetation fulfils im-
portant ecological functions such as the
trapping of pollutants, regulating river
flow and buffering against floods, and
providing habitat, shade and forage.
Riparian ecosystems are also culturally
and recreationally (and so financially)
important.
Riparian woodlands are decreasing
Verbal accounts supported by limited
ground-based and satellite images, re-
veal decreasing riparian woodland and
a loss of large trees along the rivers of
KNP, and elsewhere, over the last cen-
tury (Figure 1). An earlier SAEON study
also showed dramatic reduction in
Greefswald (riparian) Forest in Mapun-
gubwe National Park .
23
Figure 1: Satellite imagery from Google Earth showing the loss of riparian wood-
land along a stretch of the Olifants River in the Kruger National Park between
March 2009 (top) and July 2013 (bottom). Areas where mature woodland existed
have been replaced by sand banks sparsely vegetated by Croton megalabotrys
(Lavender fever-berry) and other pioneer shrubs.
Studies conducted on rivers elsewhere
in the country have revealed ripar-
ian woodland losses driven by water
abstraction, removal of vegetation to
make way for cultivation, and elephant
damage. Little research has focused on
riparian woodland dynamics either in
or out of protected areas, perhaps be-
cause these habitats represent only a
Grassroots
Vol 19
No 4
November 2019