FEATURE
% Total N
0,6
0,5
0,4
0,3
0,2
0,1
0
Thicket transformed boundary
Transformed 40m Transformed 20m Thicket 20m Thicket 40m
Vegetation type
Figure 6: Total nitrogen
in the soil in
the thicket and transformed
patches.
which, allow water infiltration as well as
the establishment of seedlings. Higher
total nitrogen in the soil produces high
forage nitrogen in the thicket areas. This
forms a valuable resource for herbivores
when the soil moisture levels drop during
the dry season and the transformed
patches stop producing leaves with a
resultant drop in the quality and quantity
of the forage these areas. This is
especially relevant during the ever-frequent
inter-annual droughts in the Albany
thicket Biome, and where annual
evaporation is nearly 4-fold the precipitation
(Jury & Levey 1993).
Figure 7: The number
of individuals and
number of species in
the thicket and transformed
areas.
This preliminary study indicates that a
mosaic of transformed grassland and
thicket patches may be the best outcome
for both production and biodiversity,
allowing animals to forage in the
cleared patches in the wet season and
to be able to find quality forage in the
thicket in the dry season. We do not yet
know what the patch sizes and distribution
should be to achieve this goal.
We also still need to understand the
ecosystem services that thicket patches
provide much better to understand the
best way to approach the management
of the thicket to gain the most benefit in
terms of ecosystem services.
Figure 8: Average
height and width in
cm of woody plants in
the thicket and transformed
areas.
These preliminary results also indicate
that restoration of transformed areas
to thicket will be a challenge. Soils in
the cleared areas are more compacted
and have lower nutrients than soils in
thicket areas. Without improving the
soil condition to a state that is closer to
that found in the thicket vegetation, it
will be exceedingly difficult to establish
young plants. The presence of animals
will further limit the success of restoration
as many animals prefer to forage in
these open areas utilizing young woody
plants extensively.
REFERENCES
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Haschick SL & Kerley GIH 1997. Factors influencing forage preference of bushbuck and boer goats for Subtropical Thicket
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Jury MR & Levey K 1993. The climatology and characteristics of drought in the Eastern Cape of South Africa International
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SANParks, 2015. Addo Elephant National Park Management Plan (2015 - 2025) (Draft). South African National Parks. http://
www.sanparks.org/conservation/park_man/ (accessed 29.04.20.).
Sigwela AM, Kerley GIH, Mills AJ & Cowling RM 2009. The impact of browsing-induced degradation on the reproduction of
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19 Grassroots Vol 20 No 3 September 2020