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The paradox of forest conservation in South Africa
Fores;;;ology Management ELSEVIER
Forest Ecologyand Management85 (1996) 35-46
The paradox of forest conservation in South Africa J.G. Castley * , G.I.H. Kerley Terrestrial
Ecology
Research
Unit. Department
of Zoology,
University
of Port Elizabeth.
P.O. Box 1600. Port Elizabeth
6000, South Africa
Abstract It would appear from the proportion of South African forests in protected areas that the habitats of vertebrate species are well protected. However, this simple figure is misleading. Firstly, the small total area of remaining forests (3000 km’) alters the vulnerability of the fauna. Secondly, a large proportion of the threatened fauna is restricted to forests and many are found in regions subject to heavy human exploitation. The apparent complacency regarding forest vertebrate conservation in South Africa requires re-evaluation in the light of this new information. The vulnerability of fauna must be carefully evaluated before management recommendations can be made, particularly for threatened species. Keywords:
Vertebrate
conservation;
Threatened
species; Afromontane;
1. Introduction The issue of conserving biodiversity is currently receiving considerable attention as an approach to managing our environment (Bond, 1989; Sayer and Whitmore, 1991; Dudley, 1992). Biodiversity conservation, although addressing the problems of maintaining species and their genetic material, also by necessity addresses the larger issues of maintaining entire ecosystems with all their processes and species interactions intact. Forests form recognisable ecosystems which support particular floral and fauna1 communities, thus forests have received particular conservation recognition in an attempt to maintain both the systems as well as the diversity of the forest biota. South African forests are apparently relatively well protected, since most are controlled by public authorities (Geldenhuys and MacDevette, 1989). However, we argue that, although these forests may be legally controlled by state and other local admin* Corresponding
author
0378-l 127/96/$15.00 Copyright PII SO378-I 127(96)03748-6
0 1996 Elsevier
Science
Coastal;
Ownership;
Exploitation
istration and conservation authorities, there is in fact considerable legal and illegal exploitation being undertaken within these areas. This could lead to declines in fauna1 populations from these areas. This is the paradox and challenge facing forest conservation in South Africa. 2. Threats to forests Tropical moist forests are renowned for being the most species-rich ecosystems on earth (Bjhmdalen, 1992; Dudley, 1992; Gentry, 1992) and are currently being altered or destroyed at a rapid rate (Sayer and Whitmore, 1991; Redford, 19921, through timber extraction and making way for escalating grazing and agricultural demands (Struhsaker, 1981; Marcot, 1992). Estimates of destruction rates vary (see Laurance, 1987; Wachtel et al., 1989; Sayer and Whitmore, 1991), but there can be no doubt that the forests of the world are under considerable threat from human exploitation (Lubke et al., 1988; Cunningham, 1988; Schwarzkopf and Rylands, 1989;
B.V. All rights
reserved.
36
J.G. Custley.
G.I.H.
Kerley/
Forest Ecology
Bjomdalen, 1992; Lawes, 1992). Associated with forest degradation or destruction are declines in the diversity and abundance of forest-dependent plant and animal species (Bennett, 1990; Kangas. 1991; Bjorndalen, 1992; MacDonald, 1992). Loss or alteration of forest habitat through grazing, agricultural pressure, logging and afforestation with exotic plantations results not only in local declines in biodiversity (Vais’Znen et al., 1986; Marcot, 1992) but also affects the biodiversity of other areas, as is the case where declines in migrating populations of neotropical birds have been linked to deforestation on temperate breeding grounds (Robbins et al., 1989). However, these large scale alterations are not the only threat to forest biodiversity. Habitat alteration through more subtle impacts is also important. In many rural areas world-wide (tropical and temperate), human communities depend heavily upon forests for a number of resources. The utilisation and extraction of these resources could negatively impact both floral and fauna1 communities (Terborgh, 1988; Thompson, 1993; Eames and Robson, 1993; Salafsky et al., 1993; Du Plessis, 1995; Bodmer et al., 1994). For example, the removal of plants for building materials, fuelwood, traditional medicines and ornamental carvings is commonplace in most African countries (Matsebula, 1993; Temu, 1993; Adegboye, 1994); southern Africa is no exception (Le Roux, 1981; Cunningham, 1988; Von dem Bussche, 1990; Bembridge and Tarlton, 1990; Leslie, 1991; Cawe, 1992; La Cock and Briers, 1992). The extraction of fuelwood is an important cause of forest degradation in some developing countries (Dudley, 1992), and in the southern African region approximately 80% of the human population relies heavily on this resource (Shaba, 1993). The gathering of fuelwood often involves the collection of dead material which does not directly cause deforestation (Bernbridge and Tarlton, 1990). However, fuelwood extraction could have negative influences and has resulted in declines in species diversity of cavity nesting birds and mammals (Mat-cot, 1992; Du Plessis, 1995). Selective logging of indigenous forests has deleterious effects on those animals which utilise mature trees as refuge sites (Johns, 1985; Lindenmayer et al., 1990; Redford, 1992). The consequences of forest destruction for biodiversity are difficult to predict as few quantitative
uml Munugrment
85 (1996)
35-46
data exist. Most evidence is anecdotal and only in extreme cases of extinction can actual declines in diversity be demonstrated (Ledig, 1992). Declines in forest vertebrates in South Africa are primarily due to habitat destruction and fragmentation (Brooke. 1984; Smithers, 1986; MacDonald, 19921, with 1 1 species declining as a result of habitat destruction. although other factors such as overexploitation of the habitat have resulted in the decline of a single species (MacDonald, 1992). In some cases the loss of species is not directly related to the loss of forest area as some species may be able to tolerate and adapt to new environmental conditions (Sayer and Whitmore, 1991). The Samango monkey, Cercopithecrts mitis. is an example of this response. These primates tolerate a wide range of vegetation physiognomies ranging from swamp forest through Afromontane forest to exotic plantations (Lawes, 1992). In contrast, other species are highly intolerant and are susceptible to even low level impacts. For example, the Cassowary. Casuarius casuarius, and Ringtail possum, Hemibelideus lemuroides. are not found in forest fragments but are restricted to large undisturbed forests (Laurance, 1987). 3. The South African 3.1. Distribution
perspective
and classi$cation
The Afromontane forests of Africa, extending down from Central Africa to the southern Cape in an archipelago-like fashion, are grouped into regional mosaics (White, 1978). South African forests fall into the Drakensberg Regional System. Although it is impossible to accurately estimate the total flora of the Afromontane region, this is a centre of regional endemism and most of the recorded 4OQOspecies are endemic (White, 1978). In some respects temperate African forests have closer affinities with tropical forests compared to temperate forests on other continents (Donald and Theron, 1983; Geldenhuys and MacDevette, 1989). South African forests are regarded as having the closest affinity to broad-leaved forests elsewhere, although conifers ( Podocarpus spp.) are present (Donald and Theron, 1983), and can be seen as being synonymous with the description of White’s Afromontane forests (White, 1978).
J.G. Castley,
G.I.H.
Kerley/
Forest
Ecology
The largest area of Afromontane forest in South Africa occurs along the south Western Cape region, while forest remnants are found both to the east and to a lesser degree in the west (Donald and Theron, 1983). Delineation of Afromontane forests in South Africa is complicated as the individual remnants are surrounded by a great diversity of lowland vegetation types as well as being situated in varying climatic regimes (White, 1978). The Eastern Cape is a fine example of this where four major phytochoria converge-the Cape, Tongaland-Pondoland, KarooNamib and Afromontane regions-resulting in a complex vegetation transition zone (Lubke et al., 1988). Three major forest veld types (Acocks, 1953) are recognised from South Africa: coastal tropical forest incorporating dune forest, mangrove forest, Knysna and Alexandria forests; inland tropical forests predominantly from the north-eastern Transvaal; and temperate and transitional forest and scrub characteristic of the Eastern Cape Amatola and Kwazulu-Natal mist-belt regions. Although broadly defined as Afromontane forests, the majority of southern African forests are primarily rainforest or undifferentiated forest. However, distinctions must be made within these classifications as to whether the forests are tall, short, evergreen, semi-deciduous, etc. Scrub forest, classified as short to low forest, comprises a large area of South African forests. Rainforests are distinguished by the prominence of growth forms such as epiphytes, lianas and root and stem structures with annual herbs absent from the forest floor, whereas undifferentiated forest are those which exhibit rapid structural and compositional changes over short distances (Geldenhuys et al., 1988). Floral and fauna1 species richness is fairly constant over the tropicaltemperate gradient (Geldenhuys and MacDevette, 1989). 3.2. Forest biome and extent
Willis (1973) defined a ‘biome’ as a whole complex of organisms naturally living together as a sociological unit. Biomes generally correspond with climatic regions and are defined in terms of all living organisms and their interactions with the environment, although they are equivalent to the concept of major plant formations. Five major terrestrial biomes
and Management
85 (1996) 35-46
31
(Forest, Fynbos, Karoo, Savanna and Grassland) are represented in southern Africa (Siegfried, 19891, although the Karoo and Savanna biomes can be further subdivided into the Succulent and Nama Karoo (Rutherford and Westfall, 1986) and the Arid and Moist Savanna (Huntley, 1984) biomes, respectively. The Forest biome is the smallest of the South African biomes and is restricted to the south Western Cape region, covering an area of 309 km2 or 0.02% of the total land surface area of South Africa (Rutherford and Westfall, 1986) (Fig. 1). Only in the south Western Cape are these forests represented by mappable units in South Africa (Rutherford and Westfall, 1986). Unmappable forest outliers lying to the west and east, incorporating both Afromontane and Coastal forest types, cover a total area of less than 3000 km* (Huntley, 1984) or between 0.1% and 0.2% of the total surface area of South Africa. These forest outlier areas are distributed in higher rainfall areas of the Fynbos, Grassland and Savanna biomes and are character&d by several large forest complexes separated by zones of no forest or only small isolated fragments (Geldenhuys and MacDevette, 1989). Forest fragments range in size from areas of less than 1 ha to the largest single forest of 25 706 ha in the south Western Cape (Geldenhuys, 1991). 3.3. Historical
extent and exploitation
It was suggested that, prior to anthropogenic impacts between 1400 and 1950, the indigenous forests and scrub forest vegetation of South Africa was once widespread, covering the majority of the south and east coasts (Acocks, 1953). However, forests have been exploited for the last 1600 years as indicated by Feely (1980). It is currently accepted that fires are the primary cause behind large scale forest destruction and fragmentation (Geldenhuys, 1993). Fires affected the extent and structure of forests until about 1900 (Phillips, 1963; Darrow, 1975) but are now largely controlled. In addition, grazing and clearing as well as historical forest exploitation have increased forest fragmentation. During the period 1778- 1939, timber extraction from almost all forests of South Africa took place, the extreme being the clearing of a number of areas (Hutchins, 1892; Phillips, 1921; King, 1941; Darrow, 1975). Both Afromontane and Coastal forests have been subject
J.C. Custiey.
Forest m
G.I.H.
Kerley/Fores~
bloma
Nama-Karoo Range
Ecology
Savanna
biome of forest
Succulent
und Management
biome Karoo
biome
8S (1996135-46
f-,yJ
Fynbos
0
Grassland
biome biome
outtiers
Fig. 1. Diagrammatic representation of the broad vegetation types (biomes) The forest biome is restricted to the southern coastline while the distribution
to recent (last century) destruction. In some areas of Natal, 80% of Afromontane complexes (Mall, 1972) and 71% of Coastal forest areas (Mathias and Bourquin, 1984) have been cleared. In the Eastern Cape, forest destruction and exploitation was driven by early inhabitants who held large communal hunts and cleared extensive areas, using slash-and-bum agricultural techniques. Before the arrival of European settlers these were the principle reasons behind declines in forest area and structure (Darrow, 1975). Large scale timber extraction between 1819 and
of South Africa of fragmented
(modified outliers
from
Rutherford
and
Westfall,
1986)
is highlighted.
1939 further aggravated forest loss and degradation. More recent forest exploitation in the form of timber extraction and other landuse practices, such as clearing for agriculture, forestry and subsistence utilisation, veld burning practices for improved grazing and water runoff, have contributed to this fragmentation (Phillips, 1963; Feely, 1980; Cooper, 1985; Geldenhuys, 1991). Larger forests are more suitable for sustained utilisation while the persistence of smaller fragments with a high ratio of forest margin to area are threatened by disturbance regimes and land-use
J.G. Castley. Table 1 Percentage
distribution
of total area of indigenous
Forest region
Management
Western Cape a Eastern Cape b Average Data from:
a Seydack
Kerley/Forest
Ecology
State forests, in the Western
Protection
Nature
56.8 30.3 43.55
21.4 18.4 19.9
(1991);
b W. Pitchford,
Department
of Forestry,
questioned from rural communities, areas in the Eastern Cape (Simelane,
Hunting
Waterlily Kubusi lsidenge Valley Zingcuka Izileni Ezindlovini Gwili Gwili Average
66 40 68 66 81 58 100 68
(%I
Proximity
to forests
Near Far Near Near Near Far Near
practices in surrounding 1991).
vegetation (Geldenhuys,
status
4.1. Forest status
Compared to most regions with large complexes of tropical and temperate forest, the remaining forests of South Africa are relatively well protected, the majority (72%) being controlled by public authorities such as Government State Forestry, local administrative regions and conservation NGOs. Although some
species and hunting
85 (1996) 35-46
and Eastern Cape, into different
39
management
classes
classes
20.4 49.1 34.75
Rural community
Table 3 Target animal
and Management
Production
Table 2 Percentage of individuals, who hunt in nearby forest 1996)
4. Conservation
G.I.H.
frequency
of different
age groups
reserves
Recreation
Research
0.4 2.2 0.3
1 0 0.5
1993.
73% of the forest complexes in the southern Cape (605 km2, incorporating the Forest biome) are well conserved, only about 20% of these forests are located within proclaimed nature reserves (Geldenhuys, 1991). The remaining forests in South Africa vary in conservation status from those without any protection to areas that are rigorously patrolled. Varying proportions of the forests in Kwazulu-Natal(28.2%), former Transvaal (18.7%), Western Cape (23.3%) and the former Transkei (30%) are privately owned (Cooper, 1985; Geldenhuys, 1991; Cooper and Swart, 1992). Many of the forest fragments and corridors and ecologically important forest areas that could be vital for the continued survival of specialised biota within conserved areas are not protected (Cooper, 1985; Geldenhuys and MacDevette, 1989). It is possible that few forests exceed the minimum critical size required for the survival of the more specialised forest biota (Geldenhuys and MacDevette, 1989). Unprotected and poorly managed forests are subject to uncontrolled poaching which depletes fauna1 diversity (Cooper and Swart, 1992; Srikosamatara, 1993). Many of the forests controlled by public authorities are managed for a selective harvest of timber and other forest products. Few areas of forest in South Africa are free from either commercial or
in rural communities
Age group (years)
Prey size targeted
Hunting
frequency
IO-15 16-25 26-30 31-45 46 and older
Small mammals/birds Medium mammals/birds Medium to large mammals Large mammals Rarely hunt
Almost every day Almost every day Generally weekends Generally weekends
(Simelane,
1996)
Reasons for hunting Recreation Recreation Recreation/subsistence/unemployed Subsistence/unemployed
40
J.G.
Custley,
G.I.H.
Kerley/
Forest
Table 4 Status, population trends and threats to populations of threatened forest Biome and forests outside the biome (outhers) Common
Species
name
Status
Ecology
vertebrate Trends
und Munugement
85 (1996)
species associated Threats
35-46
with southern
to populations
African Restricted to forests
forests in terms of the Distribution Biome
Outhers
Amphibia Heleophryne
hewitti
Anhydrophryne
rattrayi
Hewitt’s ghost frog Hogsback frog
E Res
Gaboon
V
Habitat Habitat
*
degradation degradation
*
Reptilia Bitis
gabonica
adder
3
Methuen’s dwarf gecko Setaro’s dwarf chameleon
V Res
Zululand dwarf chameleon Natal midland dwarf chameleon Forest marsh snake Mozambique shovelsnout snake East African eggeater Forest cobra
Res Res
Smithornis capensis Turdus fischeri Phoicephalus robustus
African broadbill Spotted thrush Cape parrot
V V V
Declining Declming Declining
Glaucidium Laniarius Necturinia Circaetus
Coastal barred owl Tropical boubou Neergaard’s sunbird Southern banded snake eagle Woodward’s barbet Woodward’s batis Wattle-eyed flycatcher Delegorgue’s pigeon Blackfronted bushshrike Mangrove kingfisher
R R R R
Declining
R I I I I 1
Stable Stable Declining Declining Stable Declining
Giant golden mole
V
DdiIliIlg
palliatus
Tonga red squirrel
V
pulliatus
Ngoye
red squirrel
capensis livingstonianus
Honey badger Suni Four-toed elephant
Lygodactylus
methueni
Bradypodion
setaroi
Bradypodion
nemorale
Bradypodion
thamnobates
Natriciteres Prosymna
variegata janii
Dasypeltis medici Nuju melanoleuca
P P
3 ?
P P
Development and pet collection Affotestation Habitat destruction and mining Habitat destruction Predation and agriculture
*
q:
* *
*
Habitat degradation Agriculture and mining
*
? Habitat degradation collecting
and
* *
.-
* *
*
-
*
* *
.-
*
*
-
ic
1
Aves
capense aethiopicus neergaurdi fasciolatus
Cryptolybia Batis frutrum Platysteira Columbu Telophorus Halcyon
woodwardi
peltatu delegorguei nigrifrons senegaloides
DtXlining
Stable Declining
Habitat destruction Habitat destruction Cage bird trade and selective destruction Habitat destruction Habitat destruction Fragmentation destruction
and
Habitat Habitat
destruction destruction
Habitat
destruction
II
*
-
* *
* * * * * * *
-
* F
*
-
* A *
-
* *
Mammalia Chrysopalax
Paraxerus tongensis Paraxerus ornatus Mellivora Neotrugus Petrodromus
trevelyani
tetradactylus
shrew
*
*
Declining
Predation, habitat degradation and overexploitation Habitat destruction
*
r
V
Declining
Habitat
*
*
V V R
Stable Stable Declining/ stable
destruction
*
* *
Habitat
destruction
*
-
*
J.G. Castley,
G.I.H.
Kerley/
Forest
Ecology
otul Munagement
85 (1996135-46
41
Table 4 (continued) Species
Common
name
Status
Trends
Threats to populations
Restricted to forests
Cercopithecus mitis 1abiatu.s Cricetomys gamhiunus Cioettictis ciuettu Puntheru pardus Dendrohyrux urboreus Philantombn monticola
Samango
monkey
R
DXlilliUg
Habitat destruction
*
Giant rat African civet Leopard Tree hyrax Blue duiker
R R R R R
Cepholophus natalensis Myosorex longicaudatus Amblysnmus gunningi
Red duiker Long-tailed forest shrew Gunning’s golden mole
R I I
Stable Stable Stable Stable Declining/ stable Stable Stable Stable
After Brooke (1984). Smithers (1986), Branch (1988). *, denotes presence; -, denotes absence; ?, indicates restricted; P, peripheral; I, intermediate.
that no information
subsistence exploitation (Du Plessis, 1995). Although these harvesting programmes are ostensibly conducted so as to minimise impacts on the natural environment (Geldenhuys, 1991), these activities could lead to negative long-term effects on the fauna (Gaylard, 1994). Se1ec tive logging and forest product extraction is currently being undertaken in Afromontane forest areas (State owned and privately owned) of the Western and Eastern Cape (incorporating the Ciskei and Transkei). Multiple-use management systems employed in state forests in the Western and Eastern Cape indicate that 20.4% and 49.1% of the area, respectively, are allocated for production purposes (areas able to be logged). Areas are also set aside and managed for protection and nature reserves (Table 1) (Seydack, 1991; W. Pitchford, personal communication, 1993). Although the forests of the Ciskei are extensively logged, there are no distinctions made between production or protected forest and the entire forest area is subject to logging pressure (S. Kr&ger, personal communication, 1993). Management principles controlling the exploitation of the former Ciskei forests vary to those practised in adjacent State forests. Eastern Cape forests are therefore subject to varying management practices, although these are currently being revised under new government regulations. These forests are also subjected to varying levels of illegal exploitation by rural communities. Forests offer many direct uses and indirect values
*
Habitat
currently
destruction
exists;
Distribution Biome
Outliers *
*
* *
*
* * * * *
* * *
* -
* *
E. endangered;
V, vulnerable;
R, rare; Res,
(McKenzie, 1988). Direct uses are diversified and include: the use of plants and timber for furniture, building materials, fuelwood, crafts, decorative materials and traditional medicines; subsistence hunting; grazing; recreation; and burial grounds. The indirect values include the protection of water catchment areas which preserve water and soils and the potential benefits of pharmaceutical development. Much exploitation is illegal, although activities such as the collection of fuelwood and certain building materials is not prohibited by law. However, hunting is illegal unless programmes are specifically initiated to reduce animal population levels. A number of hunting methods (snares, dogs, automatic rifles) are illegal (Anonymous, 1976, 1987). Preliminary figures from questionnaire surveys conducted in rural settlements in the Eastern Cape indicate that on average 68% of the individuals are engaged in hunting activities. These activities are concentrated in areas in close proximity to forests (Table 2) (Simelane, 1996). The primary reason for hunting in the Eastern Cape is not purely for subsistence but arises also from the conflicts between rural communities and conservation authorities regarding the ownership of and utilisation of the forests (Simelane, 1996). Threatened species are currently exploited through hunting activities as well as collection for sale of skins in traditional herbalist shops (Simelane, 1996). Hunting is undertaken by most age groups within the community. Older people tend to
42
J.G. Custley.
G.I.H.
Kerley/
Forest
Ecology
hunt predominantly larger mammals for subsistence, while younger people hunt almost purely for recreation, taking mostly birds and smaller mammals (Table 3).
and Munqement
and area
Extinct
Fynhos a (69 875 km21 Amphibians Birds Mammals Reptiles All vertebrates
Maintaining the integrity of forests is crucial for the continued existence of the vertebrate fauna that
Succulent Kuroo Amphibians Birds Mammals Reptiles All vertebrates
Status V
3
I 3 5 I 10
I I
2 5
Grassland, Savanna, and Forest highlighting the calculations (total area of region is shown in
Total no. species
E
35-46
4.2. Forest fauna and status
Table 5 Status of threatened vertebrate species from the Fynbos. Succulent Karoo. Nama Karoo, higher number of species in forests compared to omer biomes, based on species/area parentheses) Region
85 (1996)
No. species per 1000 km’
R
2 5
4 II
7
23
0.06 0.07 0.15 0.04 0.33
I 2 7 7 I7
6 10 10 27
0.0 I 0.07 0.12 0.12 0.33
a (8 I 908 km2 J
Namu Kuroo a (346 107 km2) Amphibians Birds Mammals Reptiles All vertebrates Suuannu (422 868 km’ ) Amphibians Birds Mammals Reptiles All vertebrates Grusslund (345 36 I km*) Amphibians Birds Mammals Reptiles All vertebrates
4 3 3 10
23
0 0.02 0.04 0.002 0.07
6 8 3 I7
2 13 I6 3 34
20 28 6 56
0.005 0.05 0.07 0.0 1 0.13
3 8 2 13
I II 8 6 26
18 16 9 44
0.003 0.05 0.05 0.03 0.13
I
5 5
2
I
1 2
2
3
2
I
3
I 2
3
Forest ( < 3000 !a~*) Amphibians Birds Mammals Reptiles All vertebrates a Extracted from Hilton-Taylor E, endangered; V, vulnerable;
IO
2 7 I 10
I I
14
I
I and Le Roux (1989). R, rare.
3 5 2 10
5 8 I3
8 I3 2 24
0.3 2.6 4.3 0.7 8
J.G. Castley.
G.I.H.
Kerley/Forest
Ecology
inhabits these areas, particularly those species that are restricted to forests. Relatively few studies have recorded the alpha-diversity of birds (Skead, 1964; Cody, 1983; Koen and Crowe, 1987) and mammals (Seydack, 1984) per unit area or for regional forest complexes. Some studies have considered the distribution of single species (Lawes, 1992; Gaylard, 1994) and taxa (Wirminghaus, 1990) in forest complexes. A survey of distribution maps and species habitat descriptions indicate that 40 mammals and 106 birds are represented within forest ecosystems (Maclean, 1985; Skinner and Smithers, 1990). Rautenbach (1978) recorded 76 mammals associated with forest ecosystems although his classification of forest habitat was subjective and included riverine corridors. The total number of species restricted to forest habi100
-I 80
A
_____________ I
_____________ n
______________ n
S.A. BIOMES ~RESTRICTEDC]
OVERLAP
100
B T
S.A. BIOMES IRESTRICTEDIZI
OVERLAP
Fig. 2. Percentage of threatened terrestrial mammal species (A) and herpetofaunal species (B) from the major South African biomes, including all forest areas. Overlap for each biome is defined as the number of threatened species recorded from all other biomes combined, expressed as a percentage of the total threatened fauna within the biome.
and Management
85 (1996) 35-46
43
tats is unknown, although the number of threatened species (Red Data Book species) restricted to forests include nine herpetofaunal, eight bird and eleven mammal species (Table 4). Calculation of the numbers of threatened species (amphibians, reptiles and mammals) restricted to the major biomes reveals that forests have a higher percentage of restricted species. The remaining biomes have higher degrees of species overlap with all other biomes combined. This overlap is more pronounced within mammalian taxa compared to that exhibited by amphibians and reptiles (Fig. 2). The Red Data Books (RDB) of South Africa document species which are known to be rare or declining. They aim to highlight existing or potential losses of species or populations and propose remedial conservation action where possible (Ferrar, 1989). Listings of terrestrial mammals (Smithers, 1986), birds (Brooke, 1984) and reptiles and amphibians (Branch, 1988) from the RDB indicate that 11 of the 93 herpetofauna, 13 of 102 birds and 15 of 92 mammals are characteristic of indigenous forests (Table 4). Compilations of threatened vertebrate species from the RDB for the Fynbos, Succulent and Nama Karoo biomes (Hilton-Taylor and Le Roux, 1989) include similar numbers of species to those found in forests, although the forests as a whole comprise a significantly smaller land area. This indicates that the numbers of threatened species are much higher within forests than the remaining biomes based on the number of species per unit area (Table 5). Approximately 14% of threatened terrestrial vertebrates are found within forests, although these only represent about O.l -0.2% of the area of South Africa. These fauna are therefore 7.5 times more vulnerable to extinction when compared to species from other biomes as predicted by area alone. A large proportion (84%) of these threatened species are found in regions which are currently subject to heavy exploitation (Eastern Cape and areas of KwazuluNatal). Only 16% are found within the largest wellconserved forest complex in the south western Cape. The continued existence of threatened species from these fragmentary areas is of particular concern since many fragments are threatened by expanding development and largely inadequate conservation (Jennings and Jennings, 19931, even though they are controlled by public authorities.
44
J.G. Custley.
ti.I.H.
Kerley/Forr.st
We propose that in comparison to other biomes, forest vertebrates may be particularly vulnerable to extinction, for a number of reasons. South African forest vertebrates may be particularly habitat-limited and unable to survive in altered habitats (MacDonald, 19921, as has been demonstrated elsewhere (Bennett, 1990; Dudley et al., 1992). Low biological productivity within forests may limit vertebrates to low population densities and small populations. The fragmentary nature of South African forests also limits animal population size and local distribution, with small populations being more vulnerable to decline than large populations. Furthermore, apart from reducing the effective core areas of fragments, smaller fragments are subject to higher levels of exploitation and grazing pressure exerted by rural populations. 5. Conclusion Although a number of forests in South Africa are in protected areas (Geldenhuys and MacDevette, 19891, the majority of threatened forest species have not been recorded from the largest forest complex in the south Western Cape (Table 4). Vertebrates associated with forests are subject to human impacts which include not only loss of forest area but also alteration of suitable habitat required to maintain viable populations. This habitat degradation and direct exploitation of fauna1 species is a definite threat to-the persistence of forests and their related species. Further work regarding the status of outlier vertebrate populations is required and a major conservation initiative is needed to maintain South African forest biodiversity. The formulation of forest management guidelines in consultation with rural communities in those areas under heavy utihsation is required. Schemes such as sustainable utilisation programs for selected fauna, grazing schedules and the identification and provision of alternative resources for fuelwood, building material, etc., need to be considered to aid survival of forest biota. Acknowledgements We wish to thank the following organisations for their continued support for the duration of this pro-
Ecdo~y
und Munupment
85 (1996)
35-46
gramme: Foundation for Research and Development. Department of Environmental Affairs, Eastern Cape Nature Conservation. Mazda Wildlife Fund and the University of Port Elizabeth. Funding provided by the Foundation for Research and Development and University of Port Elizabeth’s Zoology Department allowed J.G. Castley to attend the Forest Biodiversity Conference held in Canberra, Australia, during December 1994.
References Acocks. J.P.H., 1953. Veld types of South Africa. Mem. Bot. Surv. S. Afr., 57: I - 146. Adegboye, R.O., 1994. Tenure constraints and challenge of capacity building in forestry research. In: S.L. Kawje and F.B. Mwaura (Editors). Proceedings of the First International Workshop on Capacity Building in Forestry Research in Africa. African Academy of Sciences. Nairobi, Kenya, pp. 7- 1 I. Anonymous. 1976. Ciskei Forestry Act, No. 6 of 1976. Official Gazette, Ciskei Government, Republic of South Africa. Anonymous, 1987. Ciskei Nature Conservation Act, No. IO of 1987. Government Gazette, Republic of Ciskei. Bembridge, T.J. and Tarlton, J.E., 1990. Woodmel in Cisket: a headload study. S. Afr. For. J.. 154: 88-93. Bennett, A.F., 1990. Land use, forest fragmentation, and the mammalian fauna at Naringal, South-western Victoria. Amt. Wildl. Res., 17: 325-347. Bj6mdalen J.E., 1992. Tanzania’s vanishing ram forests---assessment of nature conservation values, biodiversity and importance for water catchment. Agric. Ecosys. Environ.. 40: 313 334. Bodmer, R.E.. Fang, T.G. Moya, L. and Gill, R.. 1994. Managing wildlife to conserve Amazonian forests: population biology and economic considerations of game hunting. Biol. Conserv., 67: 29-35. Bond, W.J.. 1989. Describing and conserving biotic diversity. In: B.J. Huntley (Editor), Biotic Diversity in Southern Africa: Concepts and Conservation. Oxford University Press. Cape Town, pp. 2-18. Branch, W.R., 1988. South African Red Data Book: Reptiles and Amphibians. S. Afr. Nat. Sci. Progr. Rep., 151 .CSIR, Pretoria, 240 pp. Brooke, R.K., 1984. South African Red Data Book: Birds. S. Afr. Nat. Sci. Progr. Rep., 97, CSIR, Pretoria, 213 pp. Cawe. S.. 1992. The Coastal forests of Transkei. Veld and Flora, 7x: 114-l 17. Cody, ML.. 1983. Bird diversity and density in South African forests. Oecologia, 59: 20 I-21 5. Cooper, K.H.. 1985. The Conservation Status of Indigenous Forests in Transvaal, Natal and OFS, South Africa. Wildlife Society of Southern Africa, Durban, 108 pp. Cooper, K.H. and Swart, W., 1992. Transkei Forest Survey. Wildlife Society of Southern Africa, Durban, 96 pp.
J.G. Cuurley.
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Kerley/Forest
Cunningham, A.B., 1988. Over-exploitation of medicinal plants in Natal/Kwazulu: root causes, Veld and Flora, 74: 85-87. Darrow, W.K., 1975. Forestry in the eastern Cape Border region. Bulletin 5 1, Department of Forestry, Pretoria, 99 pp. Donald, D.G.M. and Theron, J.M., 1983. Temperate broad-leaved evergreen forests of Africa south of the Sahara. In: I.D. Ovington (Editor), Temperate Broad-leaved Evergreen Forests. Elsevier, Amsterdam, pp. 135- 168. Du Plessis, M.A., 1995. The effects of fuelwood removal on the diversity of some cavity-using birds and mammals in South Africa. Biol., Consetv., 74: 77-82. Dudley, N., 1992. Forests in Trouble: A Review of the Status of Temperate Forests Worldwide. World Wide Fund for Nature, Switzerland, 261 pp. Dudley, J.P., Mensah-Ntiamoah, A.Y. and Kpelle, D.G.. 1992. Forest elephants in a rainforest fragment: preliminary findings from a wildlife conservation project in southern Ghana. Afr. J. Ecol., 30: 116-126. Eames, J.C. and Robson, C.R., 1993. Threatened primates in southern Vietnam. Oryx, 27: 146154. Feely, J.M., 1980. Did iron age man have a role in the history of Zululand’s wilderness landscapes? S. Afr. J. Sci., 76: 150- 152. Ferrar, A.A., 1989. The role of Red Data Books in conserving biodiversity. In: B.J. Huntley (Editor), Biotic Diversity in Southern Africa: Concepts and Conservation. Oxford University Press, Cape Town. pp. 136- 147. Gaylard, A., 1994. The tree hyrax (Dedrohyrux urboreus) as a rare forest species: habitat and diet. MSc. Dissertation, University of Port Elizabeth, Port Elizabeth. Geldenhuys, C.J., 1991. Distribution, size and ownership of forests in the southern Cape S. Afr. For. J., 158: 51-66. Geldenhuys, C.J.. 1993. Management of forestry plantations to become effective stepping stones and corridors for forest migration. In: D.A. Everard (Editor), The Relevance of Island Biogeographic Theory in Commercial Forestry. FRD, Pretoria, pp. 102-l 18. Geldenhuys, C.J, Knight, R.S., Russell, S. and Jarman, M.L. (Editors), 1988. Dictionary of Forest Structural Terminology. S. Afr. Natl. Sci. Progr. Rep., 147, 70 pp. Geldenhuys, C.J. and MacDcvette, D.R., 1989. Conservation status of coastal and montane evergreen forest. In: B.J. Huntley (Editor), Biotic Diversity in Southern Africa: Concepts and Conservation. Oxford University Press, Cape Town, pp. 224238. Gentry, A.H., 1992. Tropical forest biodiversity: distributional patterns and their conservational significance. Oikos, 63: 1928. Hilton-Taylor, C. and Le Roux, A., 1989. Conservation status of the fynbos and karoo biomes. In: B.J. Huntley @litor), Biotic Diversity in Southern Africa: Concepts and Conservation. Oxford University Press, Cape Town, pp. 202-223. Huntley, B.J., 1984. Characteristics of South African Biomes. In: P. de V. Booysen and N.M. Tainton (Editors), Ecological Effects of Fires in South African Ecosystems. Springer, Berlin, pp. 2-17. Hutchins, D.E., 1892. The forests of Natal. Indian For., 18: 2044205. 245-253.
Ecology
and Manqcmenr
85 (1996)
35-46
45
Jennings, B.H. and Jennings, P.J., 1993. The distribution of the tree dassie (Dendrohyrax arboreus arboreus) in the Eastern Cape. Bontebok, 8: 35-37. Johns, A.D., 1985. Selective logging and wildlife conservation in tropical rainforest: problems and recommendations. Biol. Conserv., 3 1: 355-375. Kangas, P., 1991. Macroscopic minimodels of deforestation and diversity. Ecol. Model., 57: 277-294. King, N.L., 1941. The exploitation of the indigenous forests of South Africa. J. S. Afr. For. Assoc., 6: 26-48. Koen, J.H. and Crowe, T.M., 1987. Animal-habitat relationships in the Knysna forest, South Africa: discrimination between forest types by birds and invertebrates. Gecologia, 72: 414422. La Cock, G.D. and Briers, J.H., 1992. Bark collecting at Tootabie Nature Reserve, Eastern Cape, South Africa. S. Afr. J. Bot., 58: 505-509. Laurance, W.F., 1987. The rainforest fragmentation project. Liane, 25: 9-12. Lawes, M.J., 1992. Estimates of population density and correlates of the status of the Samango monkey Cercopifhecus miris in Natal, South Africa. Biol. Conserv., 60: 197-210. Ledig, F.T., 1992. Human impacts on genetic diversity in forest ecosystems. Oikos, 63: 87- 108. Le Roux, P.J., 198 1. Supply of fuel-wood for rural populations in South Africa. S. Afr. For. J., 117: 22-27. Leslie, A.D., 1991. Indigenous forest and woodland in the kingdom of Lesotho. S. Afr. For. J., 158: 97- 103. Lindenmayer, D.B., Cunningham, R.B., Tanton, M.T. and Smith, A.P., 1990. The conservation of arboreal marsupials in the montane ash forests of the highlands of Victoria, South-East Australia: II. The loss of trees with hollows and its implications for the conservation of Leadbeater’s possum Gymnobelideus leudbeareri McCoy (Marsupialia: Petauridae). Biol. Conserv., 54: 133-145. Lubke, R.A., Tinley, K.L. and Cowling, R.M., 1988. Vegetation of the eastern Cape. In: M.N. Bruton and F.W. Gess (Editors), Towards an Environmental Plan for the Eastern Cape. Rhodes University, Grahamstown, pp. 68-87. MacDonald, I.A.W., 1992. Vertebrate populations as indicators of environmental change in South Africa. Trans. R. Sot. S. Afr., 48: 87- 122. Maclean, G.L., 1985. Roberts’ Birds of Southern Africa. John Voelcker Bird Book Fund, Cape Town 848 pp. Marcot, B.G., 1992. Conservation of Indian forests. Conserv. Biol., 6: 12-16. Mathias. I. and Bourquin, 0.. 1984. Capture of blue duiker in Natal. Lammergeyer, 33: 30-34. Matsebula, N.S., 1993. The management of indigenous forests in Swaziland. In: G.D. Piearce and D.J. Gumbo (Editors), The Ecology and Management of Indigenous Forests in Southern Africa. The Forestry Commission, Harare, Zimbabwe, pp. 25-28. McKenzie, B. (Editor), 1988. Guidelines for the sustained use of forests and forest products. Ecosystem Programmes Ckcasional Report, 35, CSIR, Pretoria, 69 pp.
46 Mall,
J.G. Custley.
G.I.H.
Kerley/Forest
E.J., 1972. The current status of mistbelt and mixed Podocarpus forest in Natal. Bothalia, 10: 595-598. Phillips, J.F.V.. 1921. The Alexandria forests. S. Afr. Gard. Ctry. Life, 1 I: 217, 219, 257-258, 276. Phillips, J., 1963. The Forests of George, Knysna and the Zitzikama-A Brief History of their Management 1778- 1939. Government Printer, Pretoria, 110 pp. Rautenbach, I.L., 1978. A numerical re-appraisal of the southern African biotic zones. Bull. Carnegie Mus. Nat. Hist.. 6: 175187. Redford, K.H., 1992. The empty forest. Bioscience, 42: 412-422. Robbins, C.S., Sauer, J.R., Greenberg, R.S. and Droege, S., 1989. Population declines in North American birds that migrate to the neotropics. Proc. Natl. Acad. Sci. USA, 86: 7658-7662. Rutherford, M.C. and Westfall, R.H., 1986. Biomes of southern Africa-an objective categorization. Mem. Bot. Surv. S. Afr.. 54: l-98. Salafsky, N., Dugelby, B.L. and Terborgh, J.W.. 1993. Can extractive reserves save the rain forest? An ecological and socioeconomic comparison of nontimber forest product extmction systems in Pet&, Guatemala, and West Kalimantan, Indonesia. Conserv. Biol., 7: 39-52. Sayer, J.A. and Whitmore, T.C., 1991. Tropical moist forests: destruction and species extinction. Biol. Conserv., 55: 199213. Schwarzkopf, L. and Rylands, A.B., 1989. Primate species richness in relation to habitat structure in Amazonian rainforest fragments. Biol. Conserv.. 48: 1- 12. Seydack, A.H.W., 1984. Application of a photo-recording device in the census of larger rain-forest mammals. S. Afr. J. Wildl. Res., 14: 10-14. Seydack, A.H.W., 1991. Inventory of South African natural forests for management purposes. S. Afr. For. J., 158: 105- 108. Shaba, M.W.M., 1993. A perspective of indigenous forests management in the SADCC Region. In: G.D. Piearce and D.J. Gumbo (Editors), The Ecology and Management of Indigenous Forests in Southern Africa. The Forestry Commission, Harare, Zimbabwe, pp. 29-37. Siegfried, W.R., 1989. Preservation of species in southern African nature reserves. In: B.J. Huntley (Editor), Biotic Diversity in Southern Africa: Concepts and Conservation. Oxford University Press, Cape Town, pp. 186-20 1. Simelane, T.S., 1996. The traditional use of indigenous verte-
Ecology
und Munugcmmt
88 11996) 35-46
brates. M.Sc. Dissertation, Umversity of Port Elizabeth, Port Elizabeth. Skead, C.J., 1964. Birds of the Amatole forests, King William’s Town and Stutterheim, C.P. Ostrich. 35: 142-159. Skinner, J.D. and Smithers, R.H.N.. 1990. Mammals of the Southem African Subregion, new edn. University of Pretoria, Pretoria, 769 pp. Smithers, R.H.N.. 1986. South African Red Data Book: Terrestrial Mammals. S. Afr. Natl. Sci. Progr. Rep., 125, 1-2 16. Srikosamatara, S., 1993. Density and biomass of large herbivores and other mammals in a dry tropical forest, western Thailand. J. Trop. Ecol.. 9: 33-43. Struhsaker, T.T.. 1981. Forest and primate conservation in east Africa. Afr. J. Ecol.. 19: 99- 1 14. Temu, A.B., 1993. Problems in resource data acquisition. In: G.D. Piearce and D.J. Gumbo (Editors), The Ecology and Management of Indigenous Forests in Southern Africa. The Forestry Commission, Harare, Zimbabwr. pp. l-6. Terborgh, J.W., 1988. The big things that run the world-a sequel to E.O. Wilson. Conserv. Biol., 2: 402-403. Thompson. H.S.S., 1993. Status of white-necked picathartesanother reason for the conservation of the Peninsula Forest, Sierra Leone. Oryx, 27: 155- 158. Vlislnen, R.A.. Jkvinen, 0. and Rauhala, P., 1986. How arc extensive, human-caused habitat alterations expressed on the scale of local bird populations in boreal forest? Omis Stand., 17: 282-292. Von dem Bussche, G.H., 1990. Indigenous high forest in the Transvaal with special reference to inventory and monitoring systems. Paper presented at the 13th Meeting of the Standing Committee for Forestry of SARCCUS in Knysna, October 1990. Wachtel, P.S., Ayanok, L., Chung, A. and Hug, J., 1989. The importance of biological diversity. World Wild Life Fund Reports, Switzerland. White, F.. 1978. The Afromontane region. In: M.J.A. Werger (Editor), Biogeography and Ecology of Southern Africa. Junk, me Hague, pp. 463-513. Willis, A.J., 1973. Introduction to Plant Ecology. Allen and Unwin, London. Wirminghaus, J.O., 1990. The role and significance of rodents in the functioning of a forest ecosystem. M.Sc. Dissertation, University of Natal, Pietermaritzburg.
Forest Ecologyand Management85 (1996) 35-46
The paradox of forest conservation in South Africa J.G. Castley * , G.I.H. Kerley Terrestrial
Ecology
Research
Unit. Department
of Zoology,
University
of Port Elizabeth.
P.O. Box 1600. Port Elizabeth
6000, South Africa
Abstract It would appear from the proportion of South African forests in protected areas that the habitats of vertebrate species are well protected. However, this simple figure is misleading. Firstly, the small total area of remaining forests (3000 km’) alters the vulnerability of the fauna. Secondly, a large proportion of the threatened fauna is restricted to forests and many are found in regions subject to heavy human exploitation. The apparent complacency regarding forest vertebrate conservation in South Africa requires re-evaluation in the light of this new information. The vulnerability of fauna must be carefully evaluated before management recommendations can be made, particularly for threatened species. Keywords:
Vertebrate
conservation;
Threatened
species; Afromontane;
1. Introduction The issue of conserving biodiversity is currently receiving considerable attention as an approach to managing our environment (Bond, 1989; Sayer and Whitmore, 1991; Dudley, 1992). Biodiversity conservation, although addressing the problems of maintaining species and their genetic material, also by necessity addresses the larger issues of maintaining entire ecosystems with all their processes and species interactions intact. Forests form recognisable ecosystems which support particular floral and fauna1 communities, thus forests have received particular conservation recognition in an attempt to maintain both the systems as well as the diversity of the forest biota. South African forests are apparently relatively well protected, since most are controlled by public authorities (Geldenhuys and MacDevette, 1989). However, we argue that, although these forests may be legally controlled by state and other local admin* Corresponding
author
0378-l 127/96/$15.00 Copyright PII SO378-I 127(96)03748-6
0 1996 Elsevier
Science
Coastal;
Ownership;
Exploitation
istration and conservation authorities, there is in fact considerable legal and illegal exploitation being undertaken within these areas. This could lead to declines in fauna1 populations from these areas. This is the paradox and challenge facing forest conservation in South Africa. 2. Threats to forests Tropical moist forests are renowned for being the most species-rich ecosystems on earth (Bjhmdalen, 1992; Dudley, 1992; Gentry, 1992) and are currently being altered or destroyed at a rapid rate (Sayer and Whitmore, 1991; Redford, 19921, through timber extraction and making way for escalating grazing and agricultural demands (Struhsaker, 1981; Marcot, 1992). Estimates of destruction rates vary (see Laurance, 1987; Wachtel et al., 1989; Sayer and Whitmore, 1991), but there can be no doubt that the forests of the world are under considerable threat from human exploitation (Lubke et al., 1988; Cunningham, 1988; Schwarzkopf and Rylands, 1989;
B.V. All rights
reserved.
36
J.G. Custley.
G.I.H.
Kerley/
Forest Ecology
Bjomdalen, 1992; Lawes, 1992). Associated with forest degradation or destruction are declines in the diversity and abundance of forest-dependent plant and animal species (Bennett, 1990; Kangas. 1991; Bjorndalen, 1992; MacDonald, 1992). Loss or alteration of forest habitat through grazing, agricultural pressure, logging and afforestation with exotic plantations results not only in local declines in biodiversity (Vais’Znen et al., 1986; Marcot, 1992) but also affects the biodiversity of other areas, as is the case where declines in migrating populations of neotropical birds have been linked to deforestation on temperate breeding grounds (Robbins et al., 1989). However, these large scale alterations are not the only threat to forest biodiversity. Habitat alteration through more subtle impacts is also important. In many rural areas world-wide (tropical and temperate), human communities depend heavily upon forests for a number of resources. The utilisation and extraction of these resources could negatively impact both floral and fauna1 communities (Terborgh, 1988; Thompson, 1993; Eames and Robson, 1993; Salafsky et al., 1993; Du Plessis, 1995; Bodmer et al., 1994). For example, the removal of plants for building materials, fuelwood, traditional medicines and ornamental carvings is commonplace in most African countries (Matsebula, 1993; Temu, 1993; Adegboye, 1994); southern Africa is no exception (Le Roux, 1981; Cunningham, 1988; Von dem Bussche, 1990; Bembridge and Tarlton, 1990; Leslie, 1991; Cawe, 1992; La Cock and Briers, 1992). The extraction of fuelwood is an important cause of forest degradation in some developing countries (Dudley, 1992), and in the southern African region approximately 80% of the human population relies heavily on this resource (Shaba, 1993). The gathering of fuelwood often involves the collection of dead material which does not directly cause deforestation (Bernbridge and Tarlton, 1990). However, fuelwood extraction could have negative influences and has resulted in declines in species diversity of cavity nesting birds and mammals (Mat-cot, 1992; Du Plessis, 1995). Selective logging of indigenous forests has deleterious effects on those animals which utilise mature trees as refuge sites (Johns, 1985; Lindenmayer et al., 1990; Redford, 1992). The consequences of forest destruction for biodiversity are difficult to predict as few quantitative
uml Munugrment
85 (1996)
35-46
data exist. Most evidence is anecdotal and only in extreme cases of extinction can actual declines in diversity be demonstrated (Ledig, 1992). Declines in forest vertebrates in South Africa are primarily due to habitat destruction and fragmentation (Brooke. 1984; Smithers, 1986; MacDonald, 19921, with 1 1 species declining as a result of habitat destruction. although other factors such as overexploitation of the habitat have resulted in the decline of a single species (MacDonald, 1992). In some cases the loss of species is not directly related to the loss of forest area as some species may be able to tolerate and adapt to new environmental conditions (Sayer and Whitmore, 1991). The Samango monkey, Cercopithecrts mitis. is an example of this response. These primates tolerate a wide range of vegetation physiognomies ranging from swamp forest through Afromontane forest to exotic plantations (Lawes, 1992). In contrast, other species are highly intolerant and are susceptible to even low level impacts. For example, the Cassowary. Casuarius casuarius, and Ringtail possum, Hemibelideus lemuroides. are not found in forest fragments but are restricted to large undisturbed forests (Laurance, 1987). 3. The South African 3.1. Distribution
perspective
and classi$cation
The Afromontane forests of Africa, extending down from Central Africa to the southern Cape in an archipelago-like fashion, are grouped into regional mosaics (White, 1978). South African forests fall into the Drakensberg Regional System. Although it is impossible to accurately estimate the total flora of the Afromontane region, this is a centre of regional endemism and most of the recorded 4OQOspecies are endemic (White, 1978). In some respects temperate African forests have closer affinities with tropical forests compared to temperate forests on other continents (Donald and Theron, 1983; Geldenhuys and MacDevette, 1989). South African forests are regarded as having the closest affinity to broad-leaved forests elsewhere, although conifers ( Podocarpus spp.) are present (Donald and Theron, 1983), and can be seen as being synonymous with the description of White’s Afromontane forests (White, 1978).
J.G. Castley,
G.I.H.
Kerley/
Forest
Ecology
The largest area of Afromontane forest in South Africa occurs along the south Western Cape region, while forest remnants are found both to the east and to a lesser degree in the west (Donald and Theron, 1983). Delineation of Afromontane forests in South Africa is complicated as the individual remnants are surrounded by a great diversity of lowland vegetation types as well as being situated in varying climatic regimes (White, 1978). The Eastern Cape is a fine example of this where four major phytochoria converge-the Cape, Tongaland-Pondoland, KarooNamib and Afromontane regions-resulting in a complex vegetation transition zone (Lubke et al., 1988). Three major forest veld types (Acocks, 1953) are recognised from South Africa: coastal tropical forest incorporating dune forest, mangrove forest, Knysna and Alexandria forests; inland tropical forests predominantly from the north-eastern Transvaal; and temperate and transitional forest and scrub characteristic of the Eastern Cape Amatola and Kwazulu-Natal mist-belt regions. Although broadly defined as Afromontane forests, the majority of southern African forests are primarily rainforest or undifferentiated forest. However, distinctions must be made within these classifications as to whether the forests are tall, short, evergreen, semi-deciduous, etc. Scrub forest, classified as short to low forest, comprises a large area of South African forests. Rainforests are distinguished by the prominence of growth forms such as epiphytes, lianas and root and stem structures with annual herbs absent from the forest floor, whereas undifferentiated forest are those which exhibit rapid structural and compositional changes over short distances (Geldenhuys et al., 1988). Floral and fauna1 species richness is fairly constant over the tropicaltemperate gradient (Geldenhuys and MacDevette, 1989). 3.2. Forest biome and extent
Willis (1973) defined a ‘biome’ as a whole complex of organisms naturally living together as a sociological unit. Biomes generally correspond with climatic regions and are defined in terms of all living organisms and their interactions with the environment, although they are equivalent to the concept of major plant formations. Five major terrestrial biomes
and Management
85 (1996) 35-46
31
(Forest, Fynbos, Karoo, Savanna and Grassland) are represented in southern Africa (Siegfried, 19891, although the Karoo and Savanna biomes can be further subdivided into the Succulent and Nama Karoo (Rutherford and Westfall, 1986) and the Arid and Moist Savanna (Huntley, 1984) biomes, respectively. The Forest biome is the smallest of the South African biomes and is restricted to the south Western Cape region, covering an area of 309 km2 or 0.02% of the total land surface area of South Africa (Rutherford and Westfall, 1986) (Fig. 1). Only in the south Western Cape are these forests represented by mappable units in South Africa (Rutherford and Westfall, 1986). Unmappable forest outliers lying to the west and east, incorporating both Afromontane and Coastal forest types, cover a total area of less than 3000 km* (Huntley, 1984) or between 0.1% and 0.2% of the total surface area of South Africa. These forest outlier areas are distributed in higher rainfall areas of the Fynbos, Grassland and Savanna biomes and are character&d by several large forest complexes separated by zones of no forest or only small isolated fragments (Geldenhuys and MacDevette, 1989). Forest fragments range in size from areas of less than 1 ha to the largest single forest of 25 706 ha in the south Western Cape (Geldenhuys, 1991). 3.3. Historical
extent and exploitation
It was suggested that, prior to anthropogenic impacts between 1400 and 1950, the indigenous forests and scrub forest vegetation of South Africa was once widespread, covering the majority of the south and east coasts (Acocks, 1953). However, forests have been exploited for the last 1600 years as indicated by Feely (1980). It is currently accepted that fires are the primary cause behind large scale forest destruction and fragmentation (Geldenhuys, 1993). Fires affected the extent and structure of forests until about 1900 (Phillips, 1963; Darrow, 1975) but are now largely controlled. In addition, grazing and clearing as well as historical forest exploitation have increased forest fragmentation. During the period 1778- 1939, timber extraction from almost all forests of South Africa took place, the extreme being the clearing of a number of areas (Hutchins, 1892; Phillips, 1921; King, 1941; Darrow, 1975). Both Afromontane and Coastal forests have been subject
J.C. Custiey.
Forest m
G.I.H.
Kerley/Fores~
bloma
Nama-Karoo Range
Ecology
Savanna
biome of forest
Succulent
und Management
biome Karoo
biome
8S (1996135-46
f-,yJ
Fynbos
0
Grassland
biome biome
outtiers
Fig. 1. Diagrammatic representation of the broad vegetation types (biomes) The forest biome is restricted to the southern coastline while the distribution
to recent (last century) destruction. In some areas of Natal, 80% of Afromontane complexes (Mall, 1972) and 71% of Coastal forest areas (Mathias and Bourquin, 1984) have been cleared. In the Eastern Cape, forest destruction and exploitation was driven by early inhabitants who held large communal hunts and cleared extensive areas, using slash-and-bum agricultural techniques. Before the arrival of European settlers these were the principle reasons behind declines in forest area and structure (Darrow, 1975). Large scale timber extraction between 1819 and
of South Africa of fragmented
(modified outliers
from
Rutherford
and
Westfall,
1986)
is highlighted.
1939 further aggravated forest loss and degradation. More recent forest exploitation in the form of timber extraction and other landuse practices, such as clearing for agriculture, forestry and subsistence utilisation, veld burning practices for improved grazing and water runoff, have contributed to this fragmentation (Phillips, 1963; Feely, 1980; Cooper, 1985; Geldenhuys, 1991). Larger forests are more suitable for sustained utilisation while the persistence of smaller fragments with a high ratio of forest margin to area are threatened by disturbance regimes and land-use
J.G. Castley. Table 1 Percentage
distribution
of total area of indigenous
Forest region
Management
Western Cape a Eastern Cape b Average Data from:
a Seydack
Kerley/Forest
Ecology
State forests, in the Western
Protection
Nature
56.8 30.3 43.55
21.4 18.4 19.9
(1991);
b W. Pitchford,
Department
of Forestry,
questioned from rural communities, areas in the Eastern Cape (Simelane,
Hunting
Waterlily Kubusi lsidenge Valley Zingcuka Izileni Ezindlovini Gwili Gwili Average
66 40 68 66 81 58 100 68
(%I
Proximity
to forests
Near Far Near Near Near Far Near
practices in surrounding 1991).
vegetation (Geldenhuys,
status
4.1. Forest status
Compared to most regions with large complexes of tropical and temperate forest, the remaining forests of South Africa are relatively well protected, the majority (72%) being controlled by public authorities such as Government State Forestry, local administrative regions and conservation NGOs. Although some
species and hunting
85 (1996) 35-46
and Eastern Cape, into different
39
management
classes
classes
20.4 49.1 34.75
Rural community
Table 3 Target animal
and Management
Production
Table 2 Percentage of individuals, who hunt in nearby forest 1996)
4. Conservation
G.I.H.
frequency
of different
age groups
reserves
Recreation
Research
0.4 2.2 0.3
1 0 0.5
1993.
73% of the forest complexes in the southern Cape (605 km2, incorporating the Forest biome) are well conserved, only about 20% of these forests are located within proclaimed nature reserves (Geldenhuys, 1991). The remaining forests in South Africa vary in conservation status from those without any protection to areas that are rigorously patrolled. Varying proportions of the forests in Kwazulu-Natal(28.2%), former Transvaal (18.7%), Western Cape (23.3%) and the former Transkei (30%) are privately owned (Cooper, 1985; Geldenhuys, 1991; Cooper and Swart, 1992). Many of the forest fragments and corridors and ecologically important forest areas that could be vital for the continued survival of specialised biota within conserved areas are not protected (Cooper, 1985; Geldenhuys and MacDevette, 1989). It is possible that few forests exceed the minimum critical size required for the survival of the more specialised forest biota (Geldenhuys and MacDevette, 1989). Unprotected and poorly managed forests are subject to uncontrolled poaching which depletes fauna1 diversity (Cooper and Swart, 1992; Srikosamatara, 1993). Many of the forests controlled by public authorities are managed for a selective harvest of timber and other forest products. Few areas of forest in South Africa are free from either commercial or
in rural communities
Age group (years)
Prey size targeted
Hunting
frequency
IO-15 16-25 26-30 31-45 46 and older
Small mammals/birds Medium mammals/birds Medium to large mammals Large mammals Rarely hunt
Almost every day Almost every day Generally weekends Generally weekends
(Simelane,
1996)
Reasons for hunting Recreation Recreation Recreation/subsistence/unemployed Subsistence/unemployed
40
J.G.
Custley,
G.I.H.
Kerley/
Forest
Table 4 Status, population trends and threats to populations of threatened forest Biome and forests outside the biome (outhers) Common
Species
name
Status
Ecology
vertebrate Trends
und Munugement
85 (1996)
species associated Threats
35-46
with southern
to populations
African Restricted to forests
forests in terms of the Distribution Biome
Outhers
Amphibia Heleophryne
hewitti
Anhydrophryne
rattrayi
Hewitt’s ghost frog Hogsback frog
E Res
Gaboon
V
Habitat Habitat
*
degradation degradation
*
Reptilia Bitis
gabonica
adder
3
Methuen’s dwarf gecko Setaro’s dwarf chameleon
V Res
Zululand dwarf chameleon Natal midland dwarf chameleon Forest marsh snake Mozambique shovelsnout snake East African eggeater Forest cobra
Res Res
Smithornis capensis Turdus fischeri Phoicephalus robustus
African broadbill Spotted thrush Cape parrot
V V V
Declining Declming Declining
Glaucidium Laniarius Necturinia Circaetus
Coastal barred owl Tropical boubou Neergaard’s sunbird Southern banded snake eagle Woodward’s barbet Woodward’s batis Wattle-eyed flycatcher Delegorgue’s pigeon Blackfronted bushshrike Mangrove kingfisher
R R R R
Declining
R I I I I 1
Stable Stable Declining Declining Stable Declining
Giant golden mole
V
DdiIliIlg
palliatus
Tonga red squirrel
V
pulliatus
Ngoye
red squirrel
capensis livingstonianus
Honey badger Suni Four-toed elephant
Lygodactylus
methueni
Bradypodion
setaroi
Bradypodion
nemorale
Bradypodion
thamnobates
Natriciteres Prosymna
variegata janii
Dasypeltis medici Nuju melanoleuca
P P
3 ?
P P
Development and pet collection Affotestation Habitat destruction and mining Habitat destruction Predation and agriculture
*
q:
* *
*
Habitat degradation Agriculture and mining
*
? Habitat degradation collecting
and
* *
.-
* *
*
-
*
* *
.-
*
*
-
ic
1
Aves
capense aethiopicus neergaurdi fasciolatus
Cryptolybia Batis frutrum Platysteira Columbu Telophorus Halcyon
woodwardi
peltatu delegorguei nigrifrons senegaloides
DtXlining
Stable Declining
Habitat destruction Habitat destruction Cage bird trade and selective destruction Habitat destruction Habitat destruction Fragmentation destruction
and
Habitat Habitat
destruction destruction
Habitat
destruction
II
*
-
* *
* * * * * * *
-
* F
*
-
* A *
-
* *
Mammalia Chrysopalax
Paraxerus tongensis Paraxerus ornatus Mellivora Neotrugus Petrodromus
trevelyani
tetradactylus
shrew
*
*
Declining
Predation, habitat degradation and overexploitation Habitat destruction
*
r
V
Declining
Habitat
*
*
V V R
Stable Stable Declining/ stable
destruction
*
* *
Habitat
destruction
*
-
*
J.G. Castley,
G.I.H.
Kerley/
Forest
Ecology
otul Munagement
85 (1996135-46
41
Table 4 (continued) Species
Common
name
Status
Trends
Threats to populations
Restricted to forests
Cercopithecus mitis 1abiatu.s Cricetomys gamhiunus Cioettictis ciuettu Puntheru pardus Dendrohyrux urboreus Philantombn monticola
Samango
monkey
R
DXlilliUg
Habitat destruction
*
Giant rat African civet Leopard Tree hyrax Blue duiker
R R R R R
Cepholophus natalensis Myosorex longicaudatus Amblysnmus gunningi
Red duiker Long-tailed forest shrew Gunning’s golden mole
R I I
Stable Stable Stable Stable Declining/ stable Stable Stable Stable
After Brooke (1984). Smithers (1986), Branch (1988). *, denotes presence; -, denotes absence; ?, indicates restricted; P, peripheral; I, intermediate.
that no information
subsistence exploitation (Du Plessis, 1995). Although these harvesting programmes are ostensibly conducted so as to minimise impacts on the natural environment (Geldenhuys, 1991), these activities could lead to negative long-term effects on the fauna (Gaylard, 1994). Se1ec tive logging and forest product extraction is currently being undertaken in Afromontane forest areas (State owned and privately owned) of the Western and Eastern Cape (incorporating the Ciskei and Transkei). Multiple-use management systems employed in state forests in the Western and Eastern Cape indicate that 20.4% and 49.1% of the area, respectively, are allocated for production purposes (areas able to be logged). Areas are also set aside and managed for protection and nature reserves (Table 1) (Seydack, 1991; W. Pitchford, personal communication, 1993). Although the forests of the Ciskei are extensively logged, there are no distinctions made between production or protected forest and the entire forest area is subject to logging pressure (S. Kr&ger, personal communication, 1993). Management principles controlling the exploitation of the former Ciskei forests vary to those practised in adjacent State forests. Eastern Cape forests are therefore subject to varying management practices, although these are currently being revised under new government regulations. These forests are also subjected to varying levels of illegal exploitation by rural communities. Forests offer many direct uses and indirect values
*
Habitat
currently
destruction
exists;
Distribution Biome
Outliers *
*
* *
*
* * * * *
* * *
* -
* *
E. endangered;
V, vulnerable;
R, rare; Res,
(McKenzie, 1988). Direct uses are diversified and include: the use of plants and timber for furniture, building materials, fuelwood, crafts, decorative materials and traditional medicines; subsistence hunting; grazing; recreation; and burial grounds. The indirect values include the protection of water catchment areas which preserve water and soils and the potential benefits of pharmaceutical development. Much exploitation is illegal, although activities such as the collection of fuelwood and certain building materials is not prohibited by law. However, hunting is illegal unless programmes are specifically initiated to reduce animal population levels. A number of hunting methods (snares, dogs, automatic rifles) are illegal (Anonymous, 1976, 1987). Preliminary figures from questionnaire surveys conducted in rural settlements in the Eastern Cape indicate that on average 68% of the individuals are engaged in hunting activities. These activities are concentrated in areas in close proximity to forests (Table 2) (Simelane, 1996). The primary reason for hunting in the Eastern Cape is not purely for subsistence but arises also from the conflicts between rural communities and conservation authorities regarding the ownership of and utilisation of the forests (Simelane, 1996). Threatened species are currently exploited through hunting activities as well as collection for sale of skins in traditional herbalist shops (Simelane, 1996). Hunting is undertaken by most age groups within the community. Older people tend to
42
J.G. Custley.
G.I.H.
Kerley/
Forest
Ecology
hunt predominantly larger mammals for subsistence, while younger people hunt almost purely for recreation, taking mostly birds and smaller mammals (Table 3).
and Munqement
and area
Extinct
Fynhos a (69 875 km21 Amphibians Birds Mammals Reptiles All vertebrates
Maintaining the integrity of forests is crucial for the continued existence of the vertebrate fauna that
Succulent Kuroo Amphibians Birds Mammals Reptiles All vertebrates
Status V
3
I 3 5 I 10
I I
2 5
Grassland, Savanna, and Forest highlighting the calculations (total area of region is shown in
Total no. species
E
35-46
4.2. Forest fauna and status
Table 5 Status of threatened vertebrate species from the Fynbos. Succulent Karoo. Nama Karoo, higher number of species in forests compared to omer biomes, based on species/area parentheses) Region
85 (1996)
No. species per 1000 km’
R
2 5
4 II
7
23
0.06 0.07 0.15 0.04 0.33
I 2 7 7 I7
6 10 10 27
0.0 I 0.07 0.12 0.12 0.33
a (8 I 908 km2 J
Namu Kuroo a (346 107 km2) Amphibians Birds Mammals Reptiles All vertebrates Suuannu (422 868 km’ ) Amphibians Birds Mammals Reptiles All vertebrates Grusslund (345 36 I km*) Amphibians Birds Mammals Reptiles All vertebrates
4 3 3 10
23
0 0.02 0.04 0.002 0.07
6 8 3 I7
2 13 I6 3 34
20 28 6 56
0.005 0.05 0.07 0.0 1 0.13
3 8 2 13
I II 8 6 26
18 16 9 44
0.003 0.05 0.05 0.03 0.13
I
5 5
2
I
1 2
2
3
2
I
3
I 2
3
Forest ( < 3000 !a~*) Amphibians Birds Mammals Reptiles All vertebrates a Extracted from Hilton-Taylor E, endangered; V, vulnerable;
IO
2 7 I 10
I I
14
I
I and Le Roux (1989). R, rare.
3 5 2 10
5 8 I3
8 I3 2 24
0.3 2.6 4.3 0.7 8
J.G. Castley.
G.I.H.
Kerley/Forest
Ecology
inhabits these areas, particularly those species that are restricted to forests. Relatively few studies have recorded the alpha-diversity of birds (Skead, 1964; Cody, 1983; Koen and Crowe, 1987) and mammals (Seydack, 1984) per unit area or for regional forest complexes. Some studies have considered the distribution of single species (Lawes, 1992; Gaylard, 1994) and taxa (Wirminghaus, 1990) in forest complexes. A survey of distribution maps and species habitat descriptions indicate that 40 mammals and 106 birds are represented within forest ecosystems (Maclean, 1985; Skinner and Smithers, 1990). Rautenbach (1978) recorded 76 mammals associated with forest ecosystems although his classification of forest habitat was subjective and included riverine corridors. The total number of species restricted to forest habi100
-I 80
A
_____________ I
_____________ n
______________ n
S.A. BIOMES ~RESTRICTEDC]
OVERLAP
100
B T
S.A. BIOMES IRESTRICTEDIZI
OVERLAP
Fig. 2. Percentage of threatened terrestrial mammal species (A) and herpetofaunal species (B) from the major South African biomes, including all forest areas. Overlap for each biome is defined as the number of threatened species recorded from all other biomes combined, expressed as a percentage of the total threatened fauna within the biome.
and Management
85 (1996) 35-46
43
tats is unknown, although the number of threatened species (Red Data Book species) restricted to forests include nine herpetofaunal, eight bird and eleven mammal species (Table 4). Calculation of the numbers of threatened species (amphibians, reptiles and mammals) restricted to the major biomes reveals that forests have a higher percentage of restricted species. The remaining biomes have higher degrees of species overlap with all other biomes combined. This overlap is more pronounced within mammalian taxa compared to that exhibited by amphibians and reptiles (Fig. 2). The Red Data Books (RDB) of South Africa document species which are known to be rare or declining. They aim to highlight existing or potential losses of species or populations and propose remedial conservation action where possible (Ferrar, 1989). Listings of terrestrial mammals (Smithers, 1986), birds (Brooke, 1984) and reptiles and amphibians (Branch, 1988) from the RDB indicate that 11 of the 93 herpetofauna, 13 of 102 birds and 15 of 92 mammals are characteristic of indigenous forests (Table 4). Compilations of threatened vertebrate species from the RDB for the Fynbos, Succulent and Nama Karoo biomes (Hilton-Taylor and Le Roux, 1989) include similar numbers of species to those found in forests, although the forests as a whole comprise a significantly smaller land area. This indicates that the numbers of threatened species are much higher within forests than the remaining biomes based on the number of species per unit area (Table 5). Approximately 14% of threatened terrestrial vertebrates are found within forests, although these only represent about O.l -0.2% of the area of South Africa. These fauna are therefore 7.5 times more vulnerable to extinction when compared to species from other biomes as predicted by area alone. A large proportion (84%) of these threatened species are found in regions which are currently subject to heavy exploitation (Eastern Cape and areas of KwazuluNatal). Only 16% are found within the largest wellconserved forest complex in the south western Cape. The continued existence of threatened species from these fragmentary areas is of particular concern since many fragments are threatened by expanding development and largely inadequate conservation (Jennings and Jennings, 19931, even though they are controlled by public authorities.
44
J.G. Custley.
ti.I.H.
Kerley/Forr.st
We propose that in comparison to other biomes, forest vertebrates may be particularly vulnerable to extinction, for a number of reasons. South African forest vertebrates may be particularly habitat-limited and unable to survive in altered habitats (MacDonald, 19921, as has been demonstrated elsewhere (Bennett, 1990; Dudley et al., 1992). Low biological productivity within forests may limit vertebrates to low population densities and small populations. The fragmentary nature of South African forests also limits animal population size and local distribution, with small populations being more vulnerable to decline than large populations. Furthermore, apart from reducing the effective core areas of fragments, smaller fragments are subject to higher levels of exploitation and grazing pressure exerted by rural populations. 5. Conclusion Although a number of forests in South Africa are in protected areas (Geldenhuys and MacDevette, 19891, the majority of threatened forest species have not been recorded from the largest forest complex in the south Western Cape (Table 4). Vertebrates associated with forests are subject to human impacts which include not only loss of forest area but also alteration of suitable habitat required to maintain viable populations. This habitat degradation and direct exploitation of fauna1 species is a definite threat to-the persistence of forests and their related species. Further work regarding the status of outlier vertebrate populations is required and a major conservation initiative is needed to maintain South African forest biodiversity. The formulation of forest management guidelines in consultation with rural communities in those areas under heavy utihsation is required. Schemes such as sustainable utilisation programs for selected fauna, grazing schedules and the identification and provision of alternative resources for fuelwood, building material, etc., need to be considered to aid survival of forest biota. Acknowledgements We wish to thank the following organisations for their continued support for the duration of this pro-
Ecdo~y
und Munupment
85 (1996)
35-46
gramme: Foundation for Research and Development. Department of Environmental Affairs, Eastern Cape Nature Conservation. Mazda Wildlife Fund and the University of Port Elizabeth. Funding provided by the Foundation for Research and Development and University of Port Elizabeth’s Zoology Department allowed J.G. Castley to attend the Forest Biodiversity Conference held in Canberra, Australia, during December 1994.
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