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SITES
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Greatham, Teesside, UK |
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West Site, Billingham, UK |
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Grimsby, Humberside, UK |
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Calais, France |
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Huelva, Spain |
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Scarlino, Italy |
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Teluk Kalung, Malaysia |
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Umbogintwini, South Africa |
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Lake Charles, USA |
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Burnie, Tasmania |
Index
by Category
Appendices
References
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Umbogintwini, South Africa
Conservation Areas at Umbogintwini Industrial Complex
 There
are two important areas that AECI and the other companies on the industrial
complex manage as wildlife reserves, the Umbogavango wetlands and woodlands
and Mamba Valley.
Umbogavango
Situated on the southern part of the industrial complex, Umbogavango
is a series of interconnected man-made wetlands that collect storm-water
run off from the whole of the complex (see Figure
28). The slow flow
of water through the pools and marshes ensures that water quality
is considerably improved before it is discharged into the Amazimtoti
River.
Around these wetland habitats are remnant areas of Natal coastal forest
and scrubland. There are also areas of planted exotic trees such as
eucalyptus that are gradually being replaced by indigenous species.
The whole 36 ha. site is designated as a private nature reserve, and
was formerly opened by the President of the Wildlife Society of Southern
Africa in 1989 and was recognised by the Natal Parks Board in 1991
as a site of Conservation Significance.
There are five wildlife-viewing hides at strategic points overlooking
the wetlands and there are trails through the woodland and scrub
habitats. Several thousand people, including large numbers of school
children,
pass through the attractive visitors centre every year and a full-time
ranger-naturalist has been in post since 1987. AECI and other companies
on the complex including Tioxide share the management and costs of
the reserve.
Wildlife at Umbogavango
Considering the reserve’s location on an industrial site in the
outskirts of a major city the diversity of wildlife is outstanding.
At least 100 species of indigenous trees, 21 species of amphibians
and reptiles, and 200 species of birds and 8 species of mammals have
been recorded in the reserve (see Tables
33, 34,
35,
36 and 37).
Neither herbaceous plant communities nor invertebrate populations have
yet
been studied
in detail, although large numbers of butterflies and dragonflies are
known to be present. Several species of preying mantis are also known
to occur.
Wetland Habitats
These are very attractive bird habitats being used by both resident
and migratory species.
Herons and egrets are particularly numerous with at least eleven species
occurring with varying degrees of regularity. These include the huge
Goliath Heron, but this is not common. In addition numbers of other
marsh birds such as African Spoonbill, Sacred Ibises and Hadeda Ibises
visit the site. In the late afternoon the ibises in particular often
arrive in considerable numbers to roost on the site.
In South Africa there is neither the diversity of species nor huge
congregations of waterfowl that occur in the northern hemisphere wetlands.
Only a dozen species of geese and ducks have been recorded at Umbogavango
and not in large numbers.
According to the reserves resident ranger the numbers of at least two
species of ducks, Cape Teal and Cape Shoveler have decreased at Umbogavango
in recent years. The reasons for this are not clear, but a number of
possibilities can be suggested. Fish have been introduced into the
Umbogavango pools and this could have altered ecological conditions
to the detriment of some species of ducks. Newman (1979) states that
the “introduction of fish into dams can have unpredictable and
undesirable results”. Bream introduced into a bird-rich wetland
in the Durban area eventually left it unsuitable for birds probably
by reducing plant and invertebrate food sources. Another possibility
is that areas of what was formerly open shallow water at Umbogavango
have reverted to over-grown swamp. This could have benefited some species
such as rails, but is not suitable for ducks such as Cape Teal and
Cape Shoveler that require shallow, open water. The situation at Umbogavango
however, is evidently a local problem since no evidence was found to
suggest that there had been a more widespread decline of the ducks
in southern Africa. The decreases in some duck species notwithstanding;
the wetlands on the site are still excellent wildlife habitat.
Woodlands and Scrub
Surrounding the wetland habitats are areas of remnant coastal forest
containing numbers of indigenous trees, shrubs and herbaceous plants.
Trees in this area include important key species for supporting wildlife
such as marula and various wild figs (see Table
34).
These woodlands support common mammals such as Vervet Monkey, Large-spotted
Genet and a small population of Blue Duiker, an indigenous species
that has been re-introduced.
Butterflies and other insects are common and diverse in both the wetland
and woodland habitats but have not yet been fully surveyed. Dragonflies
and damselflies known to occur include St Lucia Widow (Palpoleura
lucia),
Orange Pond Damselfly (Ceriagron glabrum), the Emperor Dragonfly (Anax
imperator) and Scarlet Darter (Crocotheremus erythraea). The latter
two species having a wide distribution around the world and occurring
on Tioxide sites from southern Europe to Malaysia and South Africa.
Several species of preying mantis have also been recorded including
the Common Green Mantid (Sphodromantis gastrica).
Amphibians and Reptiles
The reserve supports a considerable diversity of amphibians and reptiles
that include six species of frogs. Lizards are also well represented
and include such species as the large Water Monitor (Varanus nilocticus)
[see Table
35].
Birds
Birds have received considerable attention. The woodlands hold a diversity
of species that are generally common in the Durban area such as Natal
Robin, Cape White-eyes and various bulbuls and weavers. Also present,
but less frequently seen, are spectacular birds like Paradise Flycatcher,
Purple-crested Lourie and Narina Trogan.
At the edges of the woodlands near the site roads there are more open
areas of scrub with their own particular bird fauna. Black-bellied
Starlings seem to favour these more open areas feeding on a variety
of fruits and berries, even the white pear (Apodytes dimidiala)
that most birds seem to avoid. Both Fork-tailed Drongos and Square-tailed
Drongos are found, the latter very closely resembling, although not
closely related to, the Southern Black Flycatcher that also occurs.
This is also good habitat for various shrikes and bush
Shrikes, with Fiscal Shrike being quite common and Gorgeous Bush Shrike
more than living up to its name (see Table
36).
Mammals
Eight species of Mammals have been recorded from the Umbogintwini site, with
both Vervet Monkey and Banded Mongoose being particularly abundant.
Blue Duiker was re-introduced on to the site a number of years ago and a small
population is now firmly established.
Smaller mammals such as bats and rodents are as yet under recorded, but it is
certain that several species will be present. (see Table
37).
Conservation Initiatives at Umbogavango
A long-term conservation project on the reserve is the gradual replacement of
exotic flora by indigenous species. Blue gum (Eucalyptus globulus) has been extensively
planted in the past and many of these have grown into very tall trees. Outside
of their native Australia eucalypts are considered of low ecological value. In
several areas around the world however, a number of interesting birds have adated
to nesting in eucalyptus plantations. At Umbogavango they are one of the main
nesting sites for Black Sparrowhawk. Old sparrowhawk nests are eventually utilised
by breeding Egyptian Geese. Like all habitat management projects therefore the
re-establishment of indigenous vegetation must be a long-term and carefully planned
programme. The process must allow newly created habitat to mature sufficiently
to support existing wildlife populations before old habitats are removed.
As already mentioned some waterfowl species appear to have declined
in the wetland areas. Some habitat management might be required in
the future to maintain the
biodiversity of waterbird populations. Such management however, will need to
be based on sound observational data and be carefully planned to avoid adverse
impacts on other species.
Mamba Valley
The area known locally as Mamba Valley is a good example of the drier-type
of Natal coastal forest. This preserves woodland habitat that covers
about 4.0 ha below the railway line towards the northern end of the
Umbogintwini complex. Much of the vegetation consists of indigenous
species such as forest mahogany (Trichilia dregeana), Natal mahogany
(T. emitica) and forest croton (Croton sylvaticus). A number of these
species are widely used in herbal medicine and are valuable in supporting
other wildlife populations.
Vervet Monkeys are common in this area and Green Mambas (Dendroapis
viridis), from which the site gets its local name, are also frequently
recorded. Many of the woodland birds found in the Umbogavango Reserve
such as Natal Robin, Paradise Flycatcher and various bulbuls and
weavers are also found in Mamba Valley. Further surveys of are however,
required
in this area.
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