fliofogiil.alJournal oj'lhe Linnean So&& (1998), 64: 337-367. With 10 figures
Article ID: bj980224
Coastal forests of eastern &ca: status,
endemism patterns and their potential causes
N. D. BURGESS*
Danish Centrefor Tropical Biodiuersip, c/o <oological Museum, Universip of Copenhagen,
Uniuersiktsparken 15, DK 2100, Copenhagen 0, Denmark
G. P. CLARKE
Ihe Hermitage, Hermitage Street, Crmktme, Somerset TAI 8 8ET
W. A. RODGERS
East Afican Biodiuersip hject, c/o FAO/GEE PO. Box 2, Dar es Salaam, Tanzania
Received I1 3 4 1997; acceptedfor publication 20 Febmaty 1998
Eastern African coastal forests are located within the Swahili regional centre of endemism and
Swahili-Maputaland regional transition zone in eastern Africa, between 1' North and 25'
South, and 34-41' East. Approximately 3167 km2 coastal forest remains: 2 km2 in Somalia,
660 km2in Kenya, 697 km2in Tanzania, 16 km2in Malawi, 3 km2in Zimbabwe and perhaps
20 km?, and all but 19 are under 30 km2
1790 km2in Mozambique. Most forests are small (I
in area. Over 80% of coastal forest is located on government land, principally Forest Reserves;
only 8.3 km2is found in National Parks (6.2 km2in Kenya (Arabuko-Sokoke), 2 km2in Tanzania
(Mafia Island) and tiny patches in Zimbabwe). Coastal forests are an important and highly
threatened centre of endemism for plants (c 550 endemic species), mammals (6 species),birds
(9 species),reptiles (26 species),frogs (2 species), butterflies (79 species), snails (>86 species) and
millipedes (>>20 species). Endemic species are concentrated in the forests of the Tana River,
between Malindi in Kenya to Tanga in northern Tanzania, and in southern Tanzania. Forests
with highest numbers of endemics are: lower Tana River, Arabuko-Sokoke, Shimba Hills
(Kenya);lowland East Usambara, P u p Hills, Matumbi Hills, Rondo and Litipo and other
plateaux near Lindi (Tanzania);the Tanzanian offshore island of Pemba; Bazaruto archipelago
(Mozambique), and tiny forest remnants of southern Malawi, eastern Zimbabwe and Mozambique. Most coastal forest endemics have a narrow distributional range, often exhibiting
single-site endemism or with scattered or disjunct distributional patterns. They are best interpreted as relicts and not the result ofrecent evolution. Relictualiiation probably started with
the separation of the ancient Pan African rainforest into two parts during the Miocene. The
coastal forests are interpreted as a 'vanishing refuge' with the endemic species gradually becoming more and more relict (and presumably extinct) due historically to climatic desiccation
and more recently to human destruction.
0 1998 The Linnean Society of London
* Correspondence to Dr N. D. Burgess.
00244066/98/070337
+ 3 1 $30.00/0
337
0 1998 The Linnean Society of London
338
N. D. BURGESS E7AL.
ADDITIONAL KEY WORDS:--endemic species - evolution - centres of endemism
conservation.
-
CONTENTS
Introduction . . . . . . . . . . . . . . . . . . .
The physical background . . . . . . . . . . . .
Vegetation classification . . . . . . . . . . . .
Material and methods . . . . . . . . . . . . . .
Results . . . . . . . . . . . . . . . . . . . .
Forest distribution . . . . . . . . . . . . . .
Forest numbers and area . . . . . . . . . . . .
Forest legal status . . . . . . . . . . . . . .
Biodiversity importance . . . . . . . . . . . .
Distribution of endemic species within the coastal forest belt
Discussion . . . . . . . . . . . . . . . . . . .
Acknowledgements . . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . .
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INTRODUCTION
The identification of areas of the world where biodiversity is concentrated, and
understanding the causes behind the existence of such areas, are issues of relevance
to both conservation planning and evolutionary biology. Recent initiatives have
located and prioritized areas which are important for endemic species, or where
there are clusters of species which are representatives of older or more recent
evolutionary lineages (see Myers, 1988; 1990; International Council for Bird Preservation PCBP], 1992; World Conservation Monitoring Centre [WCMC], 1992;
World Wide Fund for Nature DIIVWF] & The World Conservation Union PUCN],
1994; Vane-Wright et al., 1991; Fjeldsb, 1994; Fjeldsl & Lovett, 1997). However,
there is no agreed methodology for such studies and several approaches have been
used (compare Crowe & Crowe, 1982; ICBP, 1992 and WWF & IUCN, 1994 with
Vane-Wright et al,, 1991; Williams & Humphries, 1994; Kershaw et a/., 1994; Fjeldsb,
1994). Other studies have tried to understand why biodiversity concentrations may
exist (see the various review articles in Fjeldsb & Lovett 1997).
One area that has been highlighted in several of these analyses is the lowland
forest vegetation of coastal eastern Africa, or, more properly, forest vegetation within
the Swahili regional centre of endemism and the adjacent Swahili-Maputaland
regional transition zone (sensu Clarke, in press c). Although these ‘coastal forests’
( s m u Clarke, in press a) have biodiversity value at the global scale, the status of the
remaining forest resource and the patterns in the distribution of the biodiversity was
until recently poorly known. The finer scale of species distributions is important for
both management planning for conservation, and in order to erect and test hypotheses
which might provide an explanation of the current distribution and evolutionary
history of the species found in these forests. This paper presents an overview of the
status of these forests, their endemic flora and fauna, and the distributional patterns
seen in the endemic species, Various hypotheses which could explain the current
distribution of the endemic species are reviewed and those which best fit the available
data are highlighted.
EASTERN AFRICAN COASTAL FORESTS
339
7 3 e physical background
Coastal forests are found in eastern Africa between 1" North and 25" South and
34" and 41" East. In addition to coastal forests this area also supports montane
forest, savannah-woodland, thicket, bushland, mangrove, grassland and farmland
vegetation (see White, 1983; Lovett & Wasser, 1993).The limits to the coastal forest
area are set by rainfall (decreasing to the North), seasonality (increasingto the South)
and by altitude, increasing to the West.
Coastal eastern Africa is predominantly a plain sloping gently upwards away from
the sea, interrupted in places by low hills and plateaux. The width of the plain is
variable. At the northern and southern limits of the coastal forest area (southern
Somalia and northern Kenya, and in southern Mozambique) it extends inland over
200 km, but on the south Kenyan and northern Tanzanian coasts, and again along
the northern Mozambique coast, it is less than 30km wide. This coastal plain
comprises a complex sequence of mainly postjurassic (C135 million years old)
sediments. These include both marine and freshwater sedimentary rocks (sandstones,
limestones, marls, shales, mudstones, and unconsolidated sediments), which are
usually of progressively younger ages the nearer they are to the present shoreline
(Kent, 1972; King, 1978). Faulting and unconformities are frequent.
In Tanzania, a chain of block-faulted mountains (the Eastern Arc Mountains:
s m u Lovett, 1988) rises steeply to 260m from the coastal plain (Griffiths, 1993).
Elsewhere the plain at first rises gradually, but then more steeply after reaching an
altitude of between 200 and 300 m, until reaching the Central African Plateau which
stretches from southern Kenya to Zimbabwe at 1300 m to 1500 m altitude (King,
1978).
Studies have shown that the soils of the coastal plain are varied and influenced
by the parent rocks, climate, degree of leaching, and physical features such as
position on a slope and degree of waterlogging (Milne, 1935, 1947; Hathout, 1972).
The most extensive soil cover is a catenary complex of closely associated soils, where
pale-coloured sandy soils on ridge-tops merge in succession to darker and more
clay-rich soils at the base of slopes (Milne, 1935; Moomaw, 1960). In places where
the clay content becomes high and drainage becomes impeded, 'black cotton' soils,
or vertisols, may develop. Deep sandy red earths, typically overlying Neogene sands,
are also found on low ridges. The limited chemical data on the soils of the coastal
forests (Hawthorne, 1984; Burgess et al., in press a, Schmidt, 1991) indicates that a
low availability of phosphorous is typical, and that the forest soils are generally
infertile and poor for agriculture.
Detailed climatic data for the coastal region of East Africa are summarized for
the 1950s through to 1973 (East Africa Meteorological Department (EAMD), 1975;
Griffiths, 1972; White, 1983; Clarke, in press b). They are also summarized in
Mozambique from 1919 to 1945 (Servicio Meteorologico Naqional, 1919-1 95 1).
The main features of the climate are that it is tropical throughout the year, there
is a low variability in the temperature and day-length, and that there is pronounced
seasonal, monthly and annual variability in the rainfall.
Rainfall
Average annual rainfall in the coastal forest area varies from 510mm/yr at
JSiunga on the north Kenya coast to almost 2000 mm/yr on the islands of Pemba
N. D. BURGESS ETAL.
340
(5.0")
Coastal stations
0.0"
Islands
5.0"
h
f%
10.0"
4
3
16.0"
3
20.0"
25.0"
30.0"
0
1000
21 00
Mean annual rainfall (mm)
Figure 1 . Mean rainfall along the eastern African coast; for geographical reference the Tana River
(T),Ruvuma River (R) and Zambesi River (Z) and the offshore islands of Pemba, Zanzibar and Mafia
(North to South) are shown.
and Mafia (Clarke, in press b). However, an average annual rainfall between 800
and 1300 mm/yr is more typical of the coastal forest area (Fig. 1). Small hills rising
from the plain are important locations of forest, as elevation increases precipitation
through orographic effects. The south-east facing slopes support moister forest
assemblages than other aspects due to their enhanced ability to trap rain moving
inland from the Indian Ocean (e.g. Hamilton & Bensted-Smith, 1989; Chapman &
White, 1970).
Rainfall is highly seasonal and variable within and between years. There is a
trend for two rainy seasons at the northern end of the coastal forest area to a single
wet season at the southern end (as discussed in Lovett, 1993a and Clarke, in press
b). This is due to the movement of the Inter-Tropical Convergence Zone (ITCZ)
which causes rainfall peaks when it passes through an area, with the peaks merging
south of Dar es Salaam in Tanzania. In SE Tanzania, up to 85% of the total annual
rainfall f d s during the wettest three months of the year. The dry season can last
for over 6 months in these areas, although a 3-4 month-long dry season is more
typical for coastal forests further north. Drought years have occurred several times
during this century as have periods of extremely heavy rain and consequent flooding.
The El Niiio/La Nifia climatic anomalies influence the climate in two areas: northern
Kenya northwards and central Mozambique southwards. In between these areas
there is a relatively higher stability in the local climatic regimes (Philander, 1989;
Diaz & Markgraf, 1992; FjeldsH et al., 1997).
Tmperature
Along the eastern African coast the mean annual temperatures are high, averaging
25OC for all areas north of the Zambezi River (Fig. 2), and the temperature variation
throughout the year is relatively low. The coolest part of the year is the austral
EASTERN AFRICAN COASTAL FORESTS
34 1
(5.0")
0.0"
Inland stations
:approx.300 km)0
5.0"
2i
8
",
-2
1
%
.&
I2
10.0"
15.0"
20.0"
25.0"
30.0"
d
Coastal stations
20
25
30
Mean annual temperature (Celsius)
Figure 2. Mean temperatures along the eastern African coast; for geographical reference the Tana
River 0,
Ruvuma River (R) and Zambesi River (Z) and the offshore islands of Pemba, Zanzibar and
Mafia (North to South) are shown.
winter of June-start October, and the warmest is the austral summer of December
to March. Extremely high temperatures do not occur and temperatures more than
38°C have only been recorded on Zanzibar and the Rufiji Flood Plain (Clarke, in
press b).
Figetation chs$cation
The most widely accepted phytogeographical classification for Africa is contained
in White's (1983) Figetation OfAfica. In White's scheme the vegetation of the coastal
lowlands of eastern Africa was recognized as distinct from vegetation types further
inland and those at increasing altitude, and the coastal lowlands were named the
Zanzibar-Inhambane regional mosaic (adjoining the Tongoland-Pondoland regional
mosaic in southern Mozambique and north-eastern South Africa). Clarke (in press
a & c) used the results of 10 years additional study in coastal eastern Africa to define
formally a Swahili regional centre of plant endemism (rangingcoastally from Somalia
to northern Mozambique) and a Swahili-Maputaland regional transition zone in
coastal portions of central and southern Mozambique (Fig. 3). The lowland coastal
forests are one of the vegetation types contained in these two phytochoria, and
possess the highest levels of endemism. Research on vegetation and species compositional change over altitudinal ranges in coastal eastern Africa (e.g. Lovett, 1996;
Lovett et aL, in press) has shown a gradation between the lowland 'coastal forest'
flora of the Swahili regional centre of endemism/Swahili-Maputaland regional
transition zone and that of the montane 'Eastern Arc' forests of the Afromontane
archipelago-like regional centre of endemism. Lovett @em.comm.) has gone further
to suggest that the lowland and montane forests should be regarded as part of the
same broad vegetation type, forming a super-regional centre of botanical endemism
342
N.D.BURGESS E T A
Figure 3. Distribution of the Swahili regional centre of endemism (A) and Swahii-Maputalandregional
transition zone (B) in relation to the former Zanzibar-Inhambane regional mosaic of White (1 983) and
the ‘coastal forest belt’ of Burgess & Clarke (inpress). Upland areas in eastern M i c a are also indicated.
EASTERN AFRICAN COASTAL FORESTS
343
which crosses several traditional phytogeographic boundaries. Critical review of this
scheme, once published, will indicate whether it will be more accepted than the
more traditional approach of White (1983) and Clarke (in press a & c).
MATERIAL AND METHODS
Forest area
Eastern African coastal forests are only found within the Swahili regional centre
of endemism and the adjacent Swahili-Maputaland regional transition zone (smu
Clarke, in press c). The area of coastal forest has been compiled from satellite images
and maps (e.g. Rodgers et al., 1985, for Tanzania), programmes of ground survey
throughout the coastal forest area, and the compilation of Forestry Department
records (e.g. Mapa Florestal, 1980; Madgwick et al., 1988; Robertson & Luke, 1993;
Saket, 1994; Burgess & Muir, 1994; Clarke, 1995; Clarke & Dickinson, 1995; Clarke
& Stubblefield, 1995).
Biodiversip data
Biodiversity data (species distributions) for the coastal forests come from both
published and unpublished sources: Somalia (Madgwick, 1988; Madgwick et al.,
1988; Burgess & Clarke, in press), Kenya (Andrews et al., 1975; Robertson & Luke,
1993; Burgess & Clarke, in press), Tanzania (Rodgers & Homewood, 1982; Rodgers
et al., 1982; 1983; Burgess & Muir, 1994; Burgess & Clarke, in press), Mozambique
(Collar & Stuart, 1988; Burgess & Clarke, in press), Malawi (Dowsett-Lemaire, 1990;
Stuart et al., 1990; Burgess & Clarke, in press) and Zimbabwe (Muller, 1991; Burgess
& Clarke, in press).
Biodiversip importance
In this paper we do not use species-richnessas a measure of biodiversity importance
as this information is not available for most coastal forests. Moreover, a large
proportion of the species in these forests are either widespread ecological generalists,
or pioneer invasive species colonizing degraded sites. Instead, we use the number
of species in a forest which are endemic to the coastal forests, or to the Swahili
regional centre of endemism and Swahili-Maputaland regional transition zone, as
a measure of biodiversity importance.
Plant species endemic to the coastal forests and other vegetation types in the
Swahili and Swahili-Maputaland areas were identified from the literature, herbaria
and extensive field work (see Clarke et al., in press for full species list). All available
published sections of the Flora $ Tmpical East A h c a and Flora Xambesiuca were
reviewed, augmented by more recent taxonomic papers and reports which include
coastal forest plant species (especially Robertson & Luke, 1993). Herbarium work
was undertaken in the University of Dar es Salaam, Botanical Museum of the
University of Copenhagen and the Royal Botanical Gardens (Kew) (by GPC). Field
work was undertaken mainly in Tanzanian coastal forests (GPC, NDB and WAR),
although visists were also made to Somalia (GPC), Kenya (GPC, NDB, WAR),
Mozambique (NDB) and Zimbabwe (GPC). Even after this intensive effort the plant
list cannot be regared as definitive as not all parts of the Floras have been published,
a considerable number of species are not fully taxonomically defined (213 of 554
344
N. D. BURGESS ETAL.
species=38 YO),and it is sometimes necessary to make a decision on the habitat of
a particular species. Using this list comparisons are made with the number of
endemic plants in the Eastern Arc mountains (Lovett, 1988). The full species list of
endemics for the Eastern Arc is not published and the methodology used to compile
the two lists may have varied somewhat, but the comparison is made to illustrate
the importance of both areas for endemic plant species.
Data on endemic vertebrates come from several recent summaries, based on
extensive field survey and literature reviews: mammals (Burgess et al., in press b),
birds (Mlingwa et al., in press), reptiles (Broadley & Howell, in press), amphibians
(Poynton, in press). A similar approach has yielded data on endemic species in a
few groups of invertebrates: butterflies (Kielland & Cordeiro, in press) and molluscs
(Verdcourt, in press). These lists are believed to include all described species and
some new but currently undescribed species (although there are probably many
more in the molluscs). Comparative data on the fauna of the Eastern Arc Mountains
comes from a recent review (Burgess et al., in press c)
Three analyses of the biodiversity data were undertaken:
(1) The overall numbers of species endemic to the Swahili regional centre of
endemism and the Swahili-Maputaland regional transition zone ( s m u Clarke, in
press c) were compiled and then divided by habitat. The resulting lists of coastal
forest endemic (the majority) and non-forest (a smaller number) species could then
be analysed, with emphasis placed on the coastal forest species.
(2) Numbers of coastal forest endemic species were assessed in relation to the
geographical units of the Flora of Tmfiaal East A h a (Polhill, 1952-) and Flora
Zambesiaca (Brenan et al., 1960-83). This allowed endemism within mapping units
for plants to be compared with vertebrates and invertebrates, which was the finest
level of resolution possible with the available data.
(3) Aggregations of coastal forest endemic species were identified. At the larger
scale sub-centres of endemism were defined for areas which possess at least 10
species of endemic plants, or three endemic vertebrates or more than three endemic
butterflies, and where the boundary of the sub-centre could be defined by the range
of one or more locally endemic species. At the smaller scale sites possessing notable
concentrations of endemic species were those forests with at least three endemic
plants, or one vertebrate or two butterflies.
Various hypotheses were tested using the available data to see which best explained
the observed distributionsand evolutionary relationships of the coastal forest endemic
species.
RESULTS
Forest distribution
The distributionsof the main coastal forests in Kenya and Tanzania are presented
in Figures 4 and 5. Forests in Kenya and northern Tanzania are located close to
the Indian Ocean. Further inland, the climate becomes too arid to support forest
vegetation, except along some rivers (e.g. Jubba in Somalia and Tana in Kenya),
at the base of the ‘Eastern Arc’ (Lovett, 1990) Mountains in Tanzania, and a few
other mountain areas in Mozambique, Malawi and Zimbabwe. In central Tanzania
the land that can support coastal forest extends inland as far as the Kilombero
EASTERN AFRICAN COASTAL FORESTS
345
Figure 4. Major coastal forests in Kenya (from data in Burgess & Muir, 1994). Labelling: 1 =Boni,
2 =Dodoni, 3 =Tana River Primate, 4 = Lower Tana, 5 =Witu, 6 = Tana Delta, 7 =Kaya Singwaya,
8 =Mangea Hill, 9 =Gede, 10 =Arabuko-Sokoke, 11 =Kambe Sacred Rocks, 12 =Kaya Starehe,
13 =Kaya Fungo, 14 =Cha Simba, 15 =Pangani Rocks, 16 = Kaya Ribe, 17 =Kaya Rabai, 18 =
Mkongani, 19 =Kaya Jibana/Kwale, 20 = Kaya Bombo, 2 1 =Kaya Tiwi, 22 = Kaya Waa, 23 =
Shimba Hills, 24 = Kaya Karnbe (Nuhaka), 25 =Diani (Jadini), 26 =Mafisini, 27 = Gongoni, 28 =
Jombo Hill,29 = Kaya Dzornbo, 30 =Mrima Hill, 3 1 =Gonja, 32 = Shimoni.
valley (c. 250km). Northern Mozambique may hold much coastal forest, but most
potential forest sites can only now be surveyed following years of civil war. Forest
data from Mozambique are currently based on satellite photographs and are not
yet confirmed by ground surveys (Mapa Florestal, 1980; Saket, 1994).Coastal forests
are difficult to recognize using remote sensing methods as they do not stand out
very distinctly from thicket or dense woodland vegetation, and thus these data may
be flawed.
Throughout coastal eastern Africa coastal forest patches are isolated from each
other, with the land in-between supporting a mosaic of farmland, savannah-woodland
and thicket. A few coastal forests are found at the base of the Eastern Arc mountains
(e.g. East Usambaras, Ngurus, Ulugurus and Udzungwas); here, forests of coastal
forest type grade with increasing altitude into sub-montane ‘Eastern Arc’ forest types
(Clarke, in press a; Lovett, 1996).
346
N. D.BURGESS MAL.
Figure 5. Major coastal forests in Tanzania (from data in Burgess & Muir, 1994). Labelling:
1 =Horohoro, 2 =Kilulu Hill,3 =Lowland Usambaras, 4 = Tongwe, 5 =Kwani/Makinyumbi, 6 =
Mkulumuzi Gorge (Amboni caves), 7 =Yambe Island, 8 =Gengagenda North and South, 9 =Mgambo,
10= Msumbugwe, 11= Pangani River, 12 =Mkwaja, 13=Kiono/Zaraninge, 14 =Ruvu North, 15=
Pande, 16=Pugu/Kazimzumbwe, 17=Ruvu South, 1 8 = V i d u , 19=Kisiju, 20=Mchungu, 21 =
Namakutwa/Nyamuete, 22 =Kiwengoma, 23 =Mafia eastern seaboard (inc. Mrora), 24 =Kilindoni,
25 = Tong’ombe, 26 =Mbinga, 27 =Mitundembea, 28 =Rungo, 29 =Ngarama North and South,
30 = Pindiro, 3 1 =Rondo, 32 =Litipo, 33 =Chitoa, 34 =Nyangamara, 35 =Ndimba, 36 = Ruawa,
37 =Matapwa, 38 =Chilangala, 39 = Mahuta, 40 =Ngezi, 4 1 =Msitu Mkuu, 42 = Ras Kiuyu, 43 =
Jozani, 44 =Muyani.
347
EASTERN AFRICAN COASTAL FORESTS
TABLE
1.
Size class
Numbers' and areas' of coastal forests in different sizes classes in eastern African countries
(based on 194 forests with area data from total of 224 known forests)
Somalia
n km'
Kenya
n km'
Tanzania
n
km'
&I
1-5
5-15
15-50
50
0
0
0
2
5
0
I1
0
5
3
37
0
1750
1.18
1.7
0
0
6
10
0
0
1
0
2.3
42.6
211.7
440
0
2
+
7
18
24
17
0
0
2
58 12.5
24 37.5
I 1 93
4 86
2 431
0
2
0
0
0
0
0
0
0
0
0
TOTAL
2
2
99 660
66
696.6
18
1790
3
16
6
2.88
(km7
0
0
Mozambique
n
km'
Malawi
n km'
1
Zimbabwe
n
km'
Totals
n
km'
70
15.9
49
92.8
41 351.7
21 526
13 2181
194 3167.4
Data from Tanzania and Mozambique are from Burgess & Muir (1994), for Somalia from Madgwick el al. (1988)
and Clarke @en. comm.), and for Zimbabwe and Malawi from Timberlake (1994), Dowsett-Lemaire (1990) and
Broadley (in litt.). The area of forest in Kenya and Mozambique is believed to be less accurate than for other
countries. The figure for Kenya quoted here is based on an assessment of the data in Robertson and Luke (1993),
and for Mozambique on data provided by the Mozambique Forest Department.
Only sites with area data have been included. There are 32 additional forests for which there is no area data, or
the data are regarded as too unreliable to be included (see note 2).
A few Kenyan sites given a very large forest area in Robertson & Luke (1 993) have been omitted because of
uncertainty about their vegetation composition. These are Boni National Reserve, North Kili Bradysfegiawoodlands,
Dodori National Reserve, Boni proposed Forest Reserve, W a y I, 11, 111 and Kokani forests, Ras Tenewi and
Lunghi proposed Forest Reserve. These are given a total area of 2382 km'(Robertson & Luke, 1993). Ruvu South
in Tanzania has also been reduced in area from 98 to 20 km' of forest as much of it is best regarded as thicket.
Eleven forests in Mozambique are given an area of at least 100 km' by the Mozambique Forest Department (total
area= 175Okm3. These are retained at their stated area until they have been visited.
'
'
Forest numbers and arza
Approximately 3 167 km2of coastal forest is included in the 194 distinct patches
of coastal forest in eastern Africa (Table 1). However, as 1790 km2 is recorded from
Mozambique where survey data are poor, the minimum area of coastal forest is
1377 km2.Somalia, Malawi and Zimbabwe have only tiny forest remnants. Tanzania
and Kenya have similar and considerably larger areas of forest. Information for
Mozambique (Mapa Florestal, 1980; Saket, 1994) suggests a number of large forest
blocks, but this almost certainly includes thicket and woodland and these data need
to be confirmed by ground survey.
The largest coastal forest with a confirmed size is the 370km2 Arabuko-Sokoke
forest in Kenya, but most are much smaller (Table 1). The full list of known forest
sites is presented in Burgess & Clarke (in press).
Forest legal status
Most coastal forest (e.g. 81.2 Yo in Kenya and 77.6 % in Tanzania) is under some
form of government control, generally as Forest Reserves (Table 2). Only nominal
areas (c. 8.2 km2 in Kenya and Tanzania, and tiny areas in Zimbabwe) are found
of the Kenyan forests are found in the
in National Parks. A further 10.8% (74km2)
Shimba Hills and Boni National Reserves.
Of the forest areas not under government control, some are protected by local
people, mainly because they have religious significance, principally in the Kaya
forests of Kenya (Robertson & Luke, 1993). These small forests only contain
N. D. BURGESS ETAL.
348
TABLE
2. Legal status of the coastal forests of Kenya and Tanzania (1994 n = 17 1 forests with legal
status data)
Categories
of status*
National Park
National
Reserve
National Monument
Game Reserve
Forest Reserve
Sacred forest
Private land
No known status
TOTALS
Kenya
Tanzania
number
area (km3
I
6.2
74
6.17
0
2
21
0
0
469. I2
13.12
95
0
95
684.1**
14
23
35
number
area (km?
2
-
13+
41
-
532
-
2
19
10
143
66
700.5**
* These status categories are arranged in decending order of protection and are briefly explained below.
** These areas are somewhat higher than in Table 1 because some sites have more than one status, e.g. a small
National Park within the Arabuko-Sokoke Forest Reserve in Kenya.
National Park. Managed by the Wildlife Sector of government, principally for the conservation of large mammal
species. This level of reservation provides any forest within it with good protection.
National Rrmves: Kenya only; sites managed by the Wildlife Sector of government, principally for the conservation
of large mammal species. The level of forest protection is generally high in these reserves.
Fmf Rmrxr: Sites managed by the Forestry Divisions of government. Sites are split into ‘protection reserves’
where no extraction is legally allowed, and ‘production reserves’ where extraction is allowed on a ‘licence’ basis.
The level of forest protection is variable, but in both protection and production reserves is generally weak, with
considerable forest exploitation being undertaken in both sub-categories of Forest Reserve status, often illegally
and in an uncontrolled way.
National Monwnmlr: Kenya only; sites managed by the National Museums of Kenya, principally for their historial
importance. The level of forest protection is variable.
Game Ram. Sites managed by the Wildlife Department, principally for large mammals. Level of protection
medium to high.
SOrrcdf0mt.x Protection is from the local population and depends on the authority of the ‘elders’, but can be very
strong.
Air.& Innd: Includes both private and government owned ranches and estates. Forests in such areas can have
high through to no protection depending on the individual owners.
No &a1 stutur: Forest is generally unprotected here. This category not present in Tanzania.
c. 0.2% of the coastal forest resource. Privately owned land (mainly estates and
ranches) hold c. 7.8% of the total forest area, and sites where the land ownership
is not known to us contain c. 10.3% of the resource.
Biodiversip importance
Coastal forests contain c. 768 endemic species (increased to c. 778 if the Pemba
Island and Tana River endemic vertebrates are included) in the eight different
biological groups which are reasonably well studied (Tables 3, 4).The Eastern Arc
Mountain forests, which are geographically close to the coastal forests, and are wellknown for possessing a large number of endemic species (Myers, 1990; Lovett &
Wasser, 1993; WWF & IUCN, 1995), contain at least 832 endemic species in the
same groups (Table 3), but these are contained in a somewhat larger area of forest.
Calculations of the percentage of forest-dependent species within the coastal
forests which are endemic to these forests (Table 3; data from Burgess and Clarke,
in press) show that highest rates of endemism are found in the forest molluscs (68’10,
EASTERN AFRICAN COASTAL FORESTS
.i
tv
TABLE
3. Endemism within eight biological groups confined to the Swahili regional centre of endemism
and Swahili-Maputaland regional transition zone (not only forests) (SW), and the eastern African
coastal forests (forest only) (CF)
Group
Global total
species*
Plants
Birds'
Mammals'
Reptiles'
Amphibians
Molluscs
Millipedes
Butterflies
250000
9672
4330
6550
4000
70 000
7000
20 000
Swahili & Forest species
Swahiliin coastal
Maputaland
forests
total sp.
I r.
4500
sw
c. 1500
85
c. 300
c. 250
I360
1 l(15)
7(10)
84
47
14
I25
~
c. 200**
-
Percentage (YO)
endemism
Number of
endemics
-
~
c.
100
-
400
sw
CF
30
3.6(5)
2.8(4)
37
5.8( 10.5)
3.5(7.1)
48(55)
14
68
CF
c. 550
5(9)
36)
23(26)
2
86
20
79
+
-
50
-
19.75
' Figure in parentheses includes the species on Pemba Island.
'Figure in parentheses includes the species in the Tana River forests. Only the described species are presented
here, there may be a further 8 coastal forest endemic small mammals when descriptions have been published.
in parenthescs includes the species found in the Tana River forests.
* Assessment of global species totals from various chapters in WCMC (1 992) and Heywood & Watson (1995). Only
the lower number of described species have been used here. For Molluscs the total is for all Molluscs, not just the
slugs and snails studied inverdcourt (in press).
** This estimated figure is only for Kenya and Tanzania.
" Figure
TABLE
4. Percentage of global endemic species totals confined to coastal forest (including Tana and
Pemba Island) and Eastern Arc forests of eastern Africa
Biological groups
Global total
Coastal forest
Percentage of
number of species
endemics,
global total unique
described in each
no. species
to coastal forests
group
Plants
Birds
Mammals
Reptiles
Amphibians
Millipedes
Molluscs (non-marine)
Butterflies
TOTALS
250 000
9672
4330
6550
c. 4000
7000
40 000
20 000
c.
550
9
6
26
2
20
86
79
7 78
+
0.226
0.093
0.140
0.390
0.050
0.280
0.215
0.395
Eastern Arc
endemics
no. species
550"
10"
10
24d
30'
30+'
55 (E&W
Usambara)*
123h
832
Percentage of
global total unique
to Eastern Arc
0.220
0.103
0.230
0.366
0.750
0.430
>O. 137
0.6 I5
Eastern Arc data sources:
"Myers (1988;1990); Lovett (1993b), Clarke et al. (in press). 'Tanzanian Biodiversity Database (and Stuart et al.
( I 993), ICBP (1992), Mlingwa ef al. (in press)). 'Tanzanian Biodiversity Database (and Kingdon & Howell (1993),
Burgess el al. (in press)). Vanzanian Biodiversity Database (and Howell (1993), Broadley & Howell (in press)).
Tanzanian Biodiversity Database (and Howell (1993), Poynton (in press)). 'Hofhan (1993), Hoffinan (in press).
YRodgers& Homewood (1982), Btuggen (1995). l'de Jong & Congdon (1993), Kielland & Cordeiro (in press).
n=86), reptiles (55%, n=26), plants (37%, n = c . 550), butterflies (20%, n=79) and
amphibians (14%,n=2). Endemism within the forest birds and mammals is much
lower (10.5%, n=9 for birds; 7.1%, n=6 for mammals). Levels of endemism for
other groups of invertebrates are more difficult to quantifjr, but for millipedes the
fauna of two small forest sites in Tanzania is more than 70% different and the
unique species may be single-site endemics (Hoffman, in press).
N. D.BURGESS ETAL.
350
Assessments of the global rate of endemism against described totals for the various
groups (Table 4; assessed from WCMC, 1992 and Heywood & Watson, 1995)
indicates that the coastal forests possess lower overall rates of endemism for these
groups than in the Eastern Arc Mountain forests. Coastal forests contain c. 0.2% of
the summed global species totals in the eight groups studied (Table 4) and the
Eastern Arc forests contain c. 0.4% of all known species in these groups. These
figures may seem small, but in relation to the land area of these regions they are
high when compared with other parts of the world. However, as the areas of the
coastal forests and Eastern Arc forests are not equal the numbers of endemic species
per unit area forest they contain is not the same. In this regard the coastal forests
are then more important than the Eastern Arc forests (coastal forests: 778 species/
3167 km2= 0.245 endemic species/km2 forest; Eastern Arc mountain forests: 832
species/5000 km2(Lovett, 1990; Fjeldsi, pers. comm.)=0.1 16 endemic species/km2
forest).
Dirtribution of endemic species within the coastal forest belt
Wuiespread coastalforest endemics
Relatively few endemic or near-endemic (also in Eastern Arc and East African
Volcanic forests) species have wide distributions within the coastal forest belt.
Examples of species with a distribution throughout, or nearly so, of the range of
the coastal forests are the trees Dialium holttii Harms, Comm$hora zantibarica (Baill.)
Fugl., Bombax rhodognaphalon Engl., Cussonia t i m m a n n i i Harms and Fmandoa magn$ca
Seem. A wide distribution is also seen in some of the birds, for example Fischer's
Greenbul Phyllmtrephusficheri (Reichenow) 1879, Green Tinkerbird Pogoniulus simplex.
(Fischer & Reichenow) 1884, Spotted Ground Thrush ~ootherafischeri(Vigors) 1831
and Tiny Greenbul Phyllastrephus debilis (Sclater) 1899. AU other endemic or nearendemic species are found much more locally within the coastal forest area. The
predominance of species with a narrow distribution has been previously noted for
plants (Brenan, 1978; Clarke et al., in press), birds (Fjeldsi & Lovett, 1997) and
butterflies (Kielland & Cordeiro, in press). In comparison, most species in the main
Guineo-Congolian lowland rainforest block to the west have a wide geographical
range, some extending throughout the forested area (Brenan, 1978; White, 1979;
Happold, 1996).
Latitudinal endemics
Plotting numbers of coastal forest endemic taxa north to south according to the
geographical divisions of the Floras of the area (Fig. 6A, B) illustrates broad
scale patterns in the distribution of endemism in plants, mammals, birds, reptiles,
amphibians and butterflies (Fig. 7A, B), which are similar between the plants and
the animals. The highest numbers of endemic species are found along the Kenyan
and Tanzanian coast, with declining numbers found in coastal forests from northern
Mozambique to Natal. The decline seen from Mozambique to South Africa is
probably a real example of the well-known decline of species-richness along the
latitudinal gradient (Rosenzweig, 1995), or perhaps an artefact caused by lower
collecting effort (particularly in northern Mozambique). A relatively low number of
endemic plants, and a relatively high number of endemic animals is recorded for
EASTERN AFRICAN COASTAL FORESTS
35 1
Figure 6. Mapping units of the Flora of T i i c a l East Ajhca (A) and the Flora <arnbesiaca (B)
the ‘Islands’division, which equates to Pemba, Zanzibar and Mafia Islands offshore
of Tanzania. Most of the faunal endemism is concentrated on Pemba Island, but
there are approximately equal rates of plant endemism between these islands.
Plotting those coastal forest endemics which are strictly confined to a single
mapping division of the Floras reveals peaks of endemism within the mapping units
relating to the Kenya coast (K7), and southern Tanzania (T8) (Fig. 8A, B). These
peaks are mainly comprised of endemic plants, although for the best studied
vertebrate group (birds) there is also an indication of a ‘double peak’ in endemism
on the mainland, but with an additional peak on endemism on the islands. In the
northern forests (Kenya coast to just south of Tanga, Tanzania) the following bird
species are endemic: Fischer’s Turaco Tauracoficheri Reichenow 1878, Sokoke Scops
Owl Otus ireneae Ripley 1966, Sokoke Pipit Anthus sokokmris van Someren 1921 and
Clarke’s Weaver Ploceus gohndi Clarke 19I3 (this area also holds the endemic nonforest species Malindi Pipit Anthus melindae Shelley 1900, Tana River Cisticola Cziticola
restricta Traylor 1967 and Violet-Breasted Sunbird Nectarinia chalcomelas Reichenow
1905). Around the Rondo Plateau in southern Tanzania there is one endemic bird
species, Reichenow’s Batis B a h reichenowi Grote 191 1, and the extremely localized
woodwardi Shelley 1895 subspecies of the Green Barbet Buccanodon oliuaceum Shelley
1880. For the other animal groups there is no obvious distributional pattern, except
352
N. D. BURGESS ETAL..
Figure 7. Distribution of coastal forest endemic species in relation to the mapping divisions of the
Flora 0fTmpical East A h a and Flora Zambesica; (A) for plants, birds, mammals, reptiles, amphibians and
butterflies; (B) for birds, mammals, reptiles, amphibians and butterflies.
Figure 8. Distribution of the coastal forest endemic species strictly confined to one of the mapping
units of the Flora .f Tmpical East A&a and Flora Zambesiaca; (A) for plants, birds, mammals, reptiles,
amphibians and butterflies; (B) for birds, mammals, reptiles, amphibians and butterflies.
EASTERN AFRICAN COASTAL FORESTS
353
Figure 9. Distribution of coastal forest endemic species strictly confined within mapping units of the
Flora of T m ~ u a East
l
A&ca and Flora zambesiaca, divided by the total area of forest remaining within
each unit.
that no strictly endemic animals are known from the largely unexplored coastal
forests of northern Mozambique.
Plotting the data of strict endemics against the area of forest now remaining (Fig.
9) shows that the strongest peak of endemism per unit area of forest is in southern
Tanzania (T8). The second most important area is the Tanzanian offshore islands,
particularly Pemba Island.
Our use of flora divisions as the mapping unit considerably overestimates the
distributional ranges of many species, and if site-by-site data were available to be
used, then the range sizes of species in these forests would be much smaller and
more focused on certain forests. For example, the Rondo Plateau area in southern
Tanzania contains around 100 endemic species, the majority of those known from
Rondo, Litipo, Chitoa and Noto forests only (around 30 km2forest: Clarke, 1995).
Moreover, there are a number of other sites which have at least 10 single-site
endemic plants (e.g. E. Usambaras, Kimboza, Pugu Hills). The entire distributional
range of these species are within the 5-20 km2forested area they inhabit.
Scat&ed or dyunct endemics
Some coastal forest endemic and near-endemic species are distributed in a patchy
(scattered) or disjunct way, particularly birds (Table 5). There are also plant genera
which have disjunct sister species in the coastal forests and in the lowland forest of
West Africa (most examples), or in Madagascar (fewer examples) (Clarke et al., in
press), and White (1983) found that 2% of the Guinea-Congolian species were also
found in the (then) Zanzibar-Inhambane regional mosaic. Habitat variation might
354
N. D. BURGESS MAL.
TABLE
5. Species of endemic coastal forest plants and vertebrates with scattered or strongly disjunct
distribution patterns within the coastal forest area. For plants there are also generic disjunctions with
Western Africa and Madagascar
Group
Species
Summary distribution
Plants
K a m i a gigm
Clcistrmthus sp. nov. &. michelsonii
Cigariphon macm+hon
Albertisia undulata
Ochna sp. nov. (Luke 2419)
Lasiodicnrr usambarmcir
Tfistemmaacuminatum
Southern Kenya and southern Tanzania
Southern Kenya and southern Tanzania
Southern Kenya and southern Tanzania
Southern Kenya and southern Tanzania
Southern Kenya and southern Tanzania
Tanzanian coast and eastern Zimbabwe
Northern Tanzania and northern
Mozambique
Mammals
Ader’s duiker Ccphnlophus &si Thomas
1918
Lesser pouched rat &mys hindn’ Thomas
1909
Zanzibar, Chale point and Arabuko-Sokoke
Birds
Sokoke Pipit Anihus s o h van
~ Someren
1921
Plain-backed Sunbird Anthnpetes nichmozui
Gunning 1909
Uluguru Violet-backed Sunbird Anthnpta
ncgkcttu Neumann 1922
Amani Sunbird An&b$tesfiaU&m&r
Sclater
& Moreau 1935
East Coast Akalat shcppadia gunningi
sobkenk Haagner 1909
Spotted Ground Thrush <oooothna gut&&
Vigors 1931
various patches, see FitzGibbon d a/., 1995
various forest patches from Sokoke to Dar
es Salaam
various forest patches
various forest patches
Sokoke, E. Usambaras, Udzungwas
various forest patches
various forest patches
Amphibians
Stephopaedes sp. nov
Meriensophyu mirranohi Loveridge 1925
Mafia and the East Usambaras
various forest patches
Reptiles
Lygodacplus uluguruenri~Pasteur 1964
L brwdrcyt Pasteur 1995
L majanum Pasteur 1995
Aparalhtus w m ’ Boulenger 1895
Ulugurus and Tongwe
Kilulu, Zaraninge and Kiwengoma Forests
Mafia and Kisiju
Pare, E. Usambara, and Uluguru
Mountains, Kazimzumbwi and Kiwengoma
Forests
conceivably provide an explanation for such patterns but for species such as Ader’s
Duiker Cephalophus adersi Thomas 1918, Sokoke Pipit Anthus sokokensk van Someren
192 1 and East Coast Akalat Sheppurdia gunningi Haagner 1909) apparently suitable
forest habitat occurs in the areas in-between those forest where these species are
currently found.
Sub-centres of endemism
Sub-centres of endemism (see methods) are found throughout the range of the
coastal forests, but particularly in Kenya and Tanzania (Table 6, Fig. 10).The ‘Lindi’
sub-centre of endemism (Rondo, Litipo, Chitoa and Noto forest) in Tanzania is the
most important area for plants and vertebrates, and contains only c. 3 0 h 2forest.
Only the combined Arabuko-Sokoke and ‘Usambara-Kwale’ sub-centres are of
similar importance, but these areas contain c. 910km2 forest. We have attempted
only a limited sub-division of the Sokoke to Usambara area, and have indicated
EASTERN AFRICAN COASTAL FORESTS
355
Tmw 6. Sub-centres of endemism within the Swahili regional centre of endemism and the SwahiliMaputaland regional transition zone, with geographical location, forest area, and key endemic species
for each local centre
Sub-centres
Tana river
Coordinates
41
0 I "20'-02"40'S
+
4O000'-4O040'E
ArabukoSokoke
and
'UsambaraKwale'
Mammals-hcolobus ru3rnitratm,
Cercocebus galeritus, Chalhobus kmyacola
Birds-Apalis chariessa chariessa, Cislicola reslricta (nonforest)
Plants--Dichapctalum sp. 1, Cynometra lukei,
Cyphoshma sp. nr bambuseti, Cyphoshma tematwn
Reptiles-Meizodon kramerii Qgosoma tanae, L.
mabuifonnis
Birds-Plocm golandi, Turacofischm'
Campeha mombmsica, Anthus melindac
Tunioidcs squamulatm, Nmtarina chalcomekzs
Plants-More than 50 species
Mammals-Tophozous hihieganhac, Rhynchmyon
chtVsopVgur two Cmdura sp. nov.
Amphibians-Hypnolius rubmmiculatus
Reptiles-Gmtmpholir prarina, Lygodac&lusconradti,
hsymna semfmciata, vphlops plalyrhyncus,
Qgodacplus kimhowellii
Butterflies-liolaus bhda hyae, Ioluc mantimus
mantimus, Aphnaeus comnae littoralis, Acraea mahapa,
Coeliades h'thloa and Gotyra diua.
03'20'-05'45'S
39"45'-38'30'E
NoNorthem Part
Key endemics
Forest area (km')
c.
Mammals-Mpchocyon chtysopygur
Birds-Phceus gokandi, Anthus mlindae
Plants-Mildbraedt'a sp. A, Dichapetalumfadenii,
E h ~ p t m apanntlia, TmIlllur w k i i
430
ArabukoSokoke to
Mombasa
Cmtral Part
Shimba Hills
to Tanzanian
border
c. 160
Plants-Uvanodmdmn sp. 3 of FTEA, Rinorea sp. ?nov
of Robertson and Luke (R & L) 1993, Combretum
sp. ?nov &. aphlatum of R & L, 1993, Dalbngia sp.
1 of R & L 1993, Salada sp. cf. eleganr, Simiresh sp. 1
of R & L 1993 ?Shmnbosiopsissp. of R & L 1993,
Pancovia sp. afF. qandensis of R & L 1993, Synsepalum
sp. cf. subconlaturn of R & L 1993, Pavetta tamnoides
Moore
S o u h Part
E. Usambara/
Tanga south
to Tongwe/
Cendagenda
c. 320
Mammals-to
Lygodacplus kimhowellii
Buttediesseveral endemic species, especially
lowland E. Usambaras
Plants-ne
endemic genus and 17 species in
lowland E. Usambaras
Pemba Island 05'20'S,
39'45'E
20
06'54'S,
39'05'E
33
P u p Hills
Cmcidura sp. nov.
Reptiles-hymns semfmkata, vphlops plaprhynchus,
+
Mammal-Ptempus voellzkowi
Birds-Nectarink pembae, <ostemps uaughi, Otm
pembk, T i np m b k
Butterflies-one species
Plants-Four species
Mammals-Cmciduru sp., Gaphinu sp. nov., possibly
f i p k h ? h pel?nkh*r
Reptiles-possibly Scolecoscps acontias
Plants-1 genus and 12 species
contd
N. D. BURGESS ETAL.
356
TABLE
6. contd
Sub-centres
'Lindi'
Coordinates
1Oo05'S,
c.
30
39' I O'E
5
Uluguru
lowlands
06'59'S,
37'48'E
c.
Udzungwa
lowlands
Bazaruto
archipelago
Mt. Mlanje
07'45'S,
36'40'E
22'S, 36"E
loo+
15'55'S,
35'30'E
Key endemics
Forest area (km3
c. 50
2
Mammals-Galogo sp. nov.
Birds-Bab rkchenow'
Reptiles-Mchnoscps rondo&, Scolecoseps litapo&,
qphlaps mnd&,
Chirindia mndoensis
Buttertlies-Two endemic species
Plant-At least 76 endemic species
Reptile-Lygoacplus williamn'
Butte*lies-Ticlna himboza and Celaenotrhinu
kimboza
Plants-2 genera and 16 species
Plants->lO plant species (6 in Magombera alone)
Reptiles-Scelotes duttoni, Scclotes inruhris, I=.ygosoma
lanceohturn
Reptiles-Bradifidion mhjme,
Rhamphleon chapmani and R.plubccps
some species which are either confined to the northern, central, or southern parts
(Table 6). With more data further sub-division of this area could probably be
achieved. The other sub-centres of endemism illustrated on Figure 10 are all of
considerably lower importance.
Endemic-rich sites
Sixteen endemic-rich sites are identified (Table 7). Most of these forests fall within
one of the sub-centres of endemism outlined above. From the point of view of
conservation planning, it is these areas which should be targeted for conservation
efforts.
DISCUSSION
A number of hypotheses could explain the distribution of the endemic coastal
forest species. These are evaluated below.
Hypothesis 1. Species distribution patterns in the endemic coastulforestfauna arejora are
colhcting artefacts
The high level of single site endemism, and scattered and disjunct distributional
patterns seen in the coastal forests flora and fauna, could be caused by a similar
pattern of collection effort, To f d y evaluate this hypothesis the collection effort at
every site and for every group would have to be known in detail, which it is not.
However, there is evidence to indicate that this explanation is false.
For example, studies over a 5 year period (10 weeks study in 25 forests) by
Frontier-Tanzania,using the same standardized survey programme, have still resulted
in scattered records for species such as the rodent Beamys hindei Thomas 1909
(FitzGibbon et al., 1995) and the toad M m o p h 2 y n e micranotis Loveridge 1925
(Poynton, in press) which were abundant where they were found, but seemingly
absent everywhere else. Other species, such as Ader's Duiker, which are known
EASTERN AFRICAN COASTAL FORESTS
35 7
1
Figure 10. Location of sub-centres of endernisrn within the coastal forest area of Kenya and Tanzania.
from two widely separated localities, were not recorded at all despite intensive survey
efforts.
For species which are easier to study, e.g. birds and trees, almost all the forests
in Kenya and many forests in Tanzania have been investigated and disjunct
distributions are seen in several species. A distinctive species can be found in one
358
N. D. BURGESS ETAL.
TABLE
7. Coastal forest sites with high endemism within the Swahili regional centre of endemism and
the Swahili-Maputaland regional transition zone, with forest status and area, numbers of endemics,
and notes on actions being undertaken to conserve the sites
Site
KENYA
Arabuko-Sokoke
Shimba Hills
Tana River Forests
TANZANIA
Lowland East Usambara ** Tanga
Rondo (not plantation), Lindi
Pugu, Coast Region
Matumbi-Kiwengoma,Coast-Lindi
Kiono - Zaraninge, Coast Region
Litipo, Lindi Region
Pemba Island (including Ngezi)
Zanzibar Island (includingJozani)
Kimboza, Morogoro Region
Gendagenda, Tanga Region
OTHERS
Mozambique, Bazaruto, ***
Malawi, S Mulanje, Nkhata Bay
Zimbabwe, Haroni-Rusitu
Status &
area*
FR, NP
NR,
FR,0 30
FR 30
FR 12
0 20
0 21
FR9
FR 14
FR/NP 4
FR4
FRs 29
No. plant No. vertebrate
endemics
endemics
4
12
>4
1
0
7
>20
>50
12
>3
>3
>16
3 4
4
2 (spp nov)
2 (spp nov)
0
1
5
>4
>4
17
>4
?
3+
3+
Notes
EU Project support via BirdLife
GTZ Project support
GEF Project support
3 x FINNIDA, 3 Not supported
Minor WCST via IUCN Holland
WCST with EU support
DIFD via WWF Tanzania
DIFD via WWF Tanzania
Minor WCST via IUCN Holland
Nosupport
1
CARE-Tanzania
1
Nosupport
1 (sp. nov) No support
3
3
?
FR = Forest Reserve; NP =National Park; NR =National Reserve; 0 = open area. * Area is forest area, not gazetted
area.
** These lowland forest areas would include: Kambai, Segoma, Manga and Kwagumi FRs managed by the East
Usambara Catchment Forest Project and Mzimbazi, Magogo and North Bombo F R s which fall outside such
project support. There is also some ungazetted closed coastal forest north of the East Usambara Mts.
*** Mozambique would also include parts of the Maqondes Plateau, although details are not available.
forest, but then not in an apparently comparable forest separated by a few kilometres
of open country.
In summary, although there has certainly been an uneven collecting intensity in
these forests and some observed species distribution patterns must be influenced by
this, the overall pattern of disjunction and site specific endemism seems to be real.
Hypothe.ris 2. Species distribution patterns in the endemic coastalforest fauna are caused Ly
climatic hisky
Changes in the climate of eastern Africa through time would influence the
vegetation types present. For forest adapted species a drylng of the climate would
reduce forest area and forest quality which may lead to relictualization in favourable
sites. Such a process may provide an explanation for the species distribution patterns
seen today. Climatic history and its potential effect on the coastal forests is reviewed
below.
Between 40 million and c. 19 million years ago tropical Afi-ica possessed a
continuous belt of forest between the East and West coasts [the ancient Pan-African
forest], indicating a wet tropical climate (Axelrod & Raven, 1978; Clarke, in press
b). Tropical rainforest species are presumed to have occupied extensive ranges in
this forest.
Around 17-18 million years ago the northern movement of Africa led to the
EASTERN AFRICAN COASTAL FORESTS
359
closure of the Tethys Ocean which caused a drying of the climate of northern
Africa. Combined with the geological process of uplift and rifting in central eastern
Africa (completed around 10 million years ago) this led to a division of the Pan
African forest into an eastern and western portion (Axelrod & Raven, 1978; Lovett,
1993aJ. The evolution of forest flora and fauna of western and eastern Africa would
have separnicd from this time.
Over the past 10 million years the climatic trend has been for ever increasing
aridity with time, with the Milankovitch climatic fluctuations superimposed onto
this trend (cf. Bennet, 1990; deMonocal, 1995). Periodically, however, there have
been wetter climatic regimes (e.g. between 9 and 6.4 million years and 4.6 and 2.43
million years ago) (Lovett, 1993a).These could have re-established forest connections
between the eastern and the western forests. Some exchange of species may have
been possible during these wet periods, reducing differences between the two forest
types.
The more severe climatic fluctuations during the Holocene (Ice Ages) have further
reduced forest cover inland of the eastern African coast, although close to the coast
relatively moist and warm climatic conditions are believed to have persisted as the
Indian Ocean remained a similar temperature as today (Prell et al., 1980). Thus the
Ice Ages may not have had as much effect on the coastal forests as the longer term
and slower gradual desiccation of the area. Brenan (1978) has previously suggested
that the nearby mountain (‘Eastern Arc’) forests may be “fragmented relicts of a
primitive and formerly more widespread forest flora not clearly recognisable elsewhere
in Africa today”. A similar conclusion for many of the Eastern Arc endemic plants
was reached by Lovett & Friis (1996). For the coastal forests this may be even more
true.
In summary, there is considerable although often circumstantial evidence to
indicate that the climate of eastern Africa has been gradually desiccating since the
Eocene, with a consequent reduction in forest cover and division of the Pan
African forest block into western (Guineo-Congolian) and eastern portions. There
is circumstantial evidence for periodic reconnection of the two forest areas north of
Lake Victoria to the Kenyan highlands (most species only reached as far as Kakamega
in Kenya) and along Lake Tanganyh and the Rukwa Rift, and also through the
Zambezian Miombo zone (southern dispersal corridor). However, current faunal
evidence of the connection of the coastal forests to those further west at the species
level is mainly found in shared species of birds, and in the East Usambara lowland
forests by the bats Hipposidms qvclops Temminck 1853 and Rousettus angolensis Bocage
1898. The coastal forests in southern Tanzania possess a far more unique speciesassemblage indicating that any past connections of lowland biota to the western
forests are more ancient. The gradual and long term desiccation of the eastern coast
of Africa will have slowly reduced both forest cover and quality and this could by
itself have caused the reduction of species ranges to very tiny areas, and also caused
the disjunctions which often found in coastal forest species. Human influence
(especially increased fires) would also have contributed to the loss of forests in a
generally drying environment.
Hypothesis 3. Species distribution pattems in the endmic coastal forestjora and fauna are
caused vicariant species-evolution
Recent local speciation may cause species to have small distributional ranges.
The degkee of local speciation in the coastal forests can be assessed by looking at
360
N. D. BURGESS E’TAL,
the numbers of closely related species in these forests. Genetic data would be the
most accurate way of assessing whether the nearest relatives of species are within
these forests and thus whether local speciation is occurring, or whether the nearest
relatives are distant geographically, or whether the species represent the sole
remaining representatives of their lineage, indicating that they are more ancient in
origin. Available data are summarized below.
The only biological group where molecular data have been interpreted in a
consistent way is the DNA-DNA hybridization study for birds by Sibley and Alquist
(1990). Recent distributional studies using these data, (Fjeldsb, 1994; Fjeldsb &
Lovett, 1997) indicate that endemic coastal forest birds are not in groups which
have been undergoing recent radiations; many seem to represent independent
lineages, some of which may date back to the Miocene. Examples of these more
ancient species are Clarke’s Weaver Ploceusgolandi Clarke 1913 which has no obvious
relatives, Sokoke Scops Owl which shows affinities with the Indomalayan 0. mjscens
Horsfield 1821 and the West African 0. ichrhynchus Shelley 1873, Kretschmer’s
Longbill which has affinities with forms in West Africa, and Tiny Greenbul
Phyllastrephus debilis Sclater 1899 which is old within the greenbul lineage (Roy et al.,
1997; unpublished). Other species from ‘older’ lineages of birds are White-winged
Apalis in the Tana river, Swynnerton’s Robin Swynnertonia swynnertoni Shelley 1896
in the lowland East Usambaras, and Reichenow’s Batis in southern Tanzania. The
four endemic species on Pemba Island could be more recently evolved, but as this
island may have been isolated from the mainland for perhaps 6 million years
(Griffiths, 1993) this would still provide a considerable period for their evolution.
The predominance of old species within the coastal forests endemics contrasts with
the Eastern Arc Mountains where a considerable proportion of the endemic species
are members of recent radiations (see Fjeldd, 1994; Fjeldsb & Lovett, 1997; Roy et
al., 1997), although ancient relicts are also found.
For the plants there is also little evidence of recent evolution in the coastal forests.
For example, the recent proliferations in the genera Impatiens and Cmtularia are
poorly represented in the coastal forest flora (see Fjeldsb & Lovett, 1997), even
though there are many species in the near-by mountain forests and elsewhere in
East Africa. At the generic level the coastal forest flora has its closet affinities with
some of the lowland drier forests in West Central Africa, indicating ancient
connections between the forests of the western and eastern Africa, and that these
lineages have persisted in the coastal forests when they have become extinct elsewhere
in eastern Africa. There are also 23 genera represented by single species in the
coastal forests (Clarke et ul., in press), further indicating that the flora contains relict
members of lineages which have gone extinct elsewhere, and that these species are
not the products of recent evolution.
Data for other biological groups are more difficult to assess. For the mammals
and butterflies there is evidence of local differentiation to sub-species level on the
off-shore islands and some mainland forests (see Archer & Turner, 1993; Kingdon
& Howell, 1993). For the butterflies there has also been apparent speciation within
the coastal forests, particularly in the Papilionidae (especially in Charuxes and Acraea),
and in the Lycaeindae (especially in Baliochila, Pentila and T i m i m u ) , but the age of
these speciation events is not known.
Taxonomists using morphological features in mammals, reptiles and amphibians
regard many of the endemic species in the coastal forests as ‘primitive’ (chapters in
Burgess & Clarke, in press). Examples are the endemic antelope Ader’s duiker, the
EASTERN AFRICAN COASTAL FORESTS
36 I
elephant shrews Rhynchocyon ChTsopyp Giinther 1881 and R. petmi Bocage 1880,
the rodent Beamys hindei Thomas 1909, and some true shrews. In the reptiles several
‘primitive’ forms are also known from these forests (Broadley and Howell, in press).
Although these data may be flawed, they further indicate that recent speciation has
not been a major cause of the high number of endemics in the coastal forests.
In conclusion, the hypothesis that the endemics of the coastal forests have recently
evolved there is not well supported by the data. There are far more examples of
species representing relict or ancient lineages in the coastal forest endemics, than of
species from groups undergoing rapid recent speciation.
Hypothesis 4. Species distribution pattmu in the endemic coastalforest fauna andjora are
caused by human disturbance
If there have been major changes in forest extent and forest quality due to the
activities of man, this could explain the relict distributional patterns seen in many
coastal forest endemic taxa. There is abundant evidence of recent and past human
disturbances to the forests of the coastal area (see review in Clarke & Karoma, in
press), but the effects on the biota are more difficult to assess. Some of the more
probable effects of humans on the distribution of coastal forests and their speciescomposition are outlined below.
The increased incidence of fire following the development of its use by hominidd
humans (Hall, 1984; Clark & Harris, 1985; Kielland-Lund, 1988) probably assisted
in the fragmentation and destruction of drier fire-intolerant coastal forests in favour
of fire-tolerant savanna-woodland vegetation, perhaps over time periods measured
in hundreds of millennia. This process would have destroyed forests and killed
populations of coastal forest species in fire-prone areas, especially in the driest parts
of the lowlands.
A gradually increasing human population of agricultural peoples (Kjekshus, 1977;
Sutton, 1990; Clarke & Karoma, in press) would have converted forest areas to
farmland. People would presumably have selectively chosen areas which were easier
to clear and better to cultivate, and hence forest areas possessing large and tall trees
indicating better soils would have been lost first (e.g. at the base of the Eastern Arc
Mountains). The few known sites remaining are important centres of endemism
(e.g. East Usambara and Uluguru lowlands). Forest clearance to supply iron smelting
activities is also believed to have been important in the East Usambaras (Schmidt,
1989), probably including some coastal forests.
The arrival of trading and colonial powers in the area allowed valuable products
of the coastal forests (timber etc.) to be exploited more systematically (FreemanGrenville, 1967; Kjekshus, 1977; Sutton, 1990). Over the past 100 years, the trade
in timber (Burgess & Mbwana, in press), and the establishment of plantations (spices,
coconuts, sisal, cashewnuts etc.) (Clarke & Karoma, in press) have removed many
coastal forests and degraded others. Coastal forest would have been preferentially
lost from areas close to major towns, from areas of the best soils, and areas with a
better climate for crops. The lowland East Usambaras are an example where
considerable deforestation has occurred (Schmidt, 1989),and where natural lowland
coastal forests have been replaced by teak Zctoniu grandis.
In summary, human use of forests has probably had a severe effects on the driest
forest types (destroyed by fires), and on those forests growing on good soils and in
climates suitable for cultivation (forest lost to agriculture, plantations, and because
I
362
N. D.BURGESS ETAL.
they possessed the best timber). The extent to which these factors have caused the
present species distribution patterns is not known, but may have been one of the
reasons why most forests are now located in areas with poorer soils, and on remote
and more hilly positions. Human activity may therefore have contributed to the
isolation of species of plants and animals to a few sites.
Hypothesis 4. Species dktribution patterns in the e n h i c coastal forest fauna andjora are
caused sea-level changes
The coastline of eastern Africa has altered considerably over the past millions of
years (Kent, 1972; 1974) and much of the coastal plain was inundated in the past.
These changes mean that most sites below 100 m altitude would have been under
the sea at some point during the past 30 million years, often several times. Inundations
by the sea may have flooded areas of coastal forest, and thus caused the local
extinction of species, or restricted them to areas of higher ground. The last major
inundation was between 18 and 12 million years ago. This is the maximum possible
age of most coastal forest sites. It seems possible that a few of the coastal forest
endemic species could be inundation relicts which survived on islands when the sea
level was higher than today, although this cannot be tested.
Forests of the lowest ground closest to the sea (e.g. some forests on beach ridges)
cannot have existed on those sites for more than ten thousand years as such features
have developed mainly since the end of the last Ice Age (Alexander, 1969; Cooke,
1974). In these locations all the species must be recent colonists, have gradually
migrated there as the sealevels have changed, or have evolved at that location.
Kisiju forest in Tanzania is-an example of such a forest and is species-poor with
few endemics (one near-endemic plant and reptile).
In summary, there have certainly been considerable changes in the position of
the coastline of eastern Africa. These changes are associated with tectonic events
since the Miocene which have also uplifted many of the areas which currently
support forest. The effects of coastline changes on species distributional patterns are
not clear, but areas of higher ground may have been islands at some periods, and
it is these areas which possess the higher numbers of endemic species.
Best current explanationfor the distribution of& endemicjlora and fauna in the ea.s& Afican
coastal forests
When considered together, available evidence indicates that most of the coastal
forest endemic species are representatives of lineages which evolved millions of years
ago and have become relict in the coastal forests as the available lowland forest
habitat in eastern Africa has shrunk. A much lower proportion of species represent
lineages undergoing recent speciation, and the coastal forests do not seem to an
important centre for recent evolution.
The current distribution of the coastal forest endemics may reflect the location
of areas which have remained most climatically suitable over these long periods,
and at the same time have not been degraded too greatly by the activities of man,
where random extinction events have not removed the species from an otherwise
suitable area, and where sea level changes have not inundated forest areas.
In comparison, the nearby Eastern Arc mountain forests (see Lovett & Wasser,
1993) have a higher proportion of species which are members of recent speciesradiations, and hence there are seemingly greater rates of evolution in the Eastern
EASTERN AFRICAN COASTAL FORESTS
363
Arc forests than in the coastal forests. We assess the situation in the coastal forests
as rather similar to that described for the islands surrounding Africa (Cronk, 1997):
the majority of the endemic species found in the coastal forests are relict endemics
as they are either deep-branches according to DNA phylogenies and other evidence,
or are regarded by traditional taxonomists as ‘primitive’ forms, or are the sole (or
one of a very few) surviving representatives of their genudlineage. There are few
examples of endemics in groups where active speciation is known to have recently
occurred. Indeed, the coastal forests may be an example of a ‘vanishing refuge’
(Vanzolini & Williams, 1981) where the forests are shrinking due to climatic
desiccation and human influence, and endemic species either become increasingly
relict and disjunctly distributed within the remaining forests (and eventually going
extinct), or adapt to the drier and less forested conditions (e.g. the endemic bird
species on Pemba Island).
ACKNOWLEDGEMENTS
We would like to thank the following for their assistance in compiling the data
used in this paper: Don Broadley, Kim Howell, John Poynton, Bernard Verdcourt,
Jan Kielland, Norbert Cordeiro, Steve Collins, Torben Larsen, Richard Hoffman,
Clare FitzGibbon, Paul Honess, Paula Jenkins, Dieter Kock, Anya Cockle, Charles
Mlingwa, Edward Waiyaki, Leon Bennun, Leonard Mwasumbi, Kaj Vollesen,
Ann Roberston and Quentin Luke. We would also like to thank the Society for
Environmental Exploration, and the Faculty of Science of the University of Dar es
Salaam for their collaborative work under the Frontier-Tanzania Coastal Forest
Research Programme, with which two of us were formerly involved 1989-1996
(NDB) and 1991-1993 (GPC). Of those involved with this programme we would
especially like to thank the Hon. Juma Kapuya (formerly Frontier-Tanzania coordinator at the University of Dar es Salaam (UDSM)), Kim Howell, Charles
Mlingwa, Charles Msuya (Zoology Department, UDSM) and Leonard Mwasumbi,
Frank Mbago and Herji Suleiman (Botany Department, UDSM), and Clare Ansell,
Julian Bayliss, Mike Brewin, Alex Dickinson, Andy Lowe, Paul Matthews, Cath
Muir, Katty Ponder, Douglas She3 and Leigh Stubblefield of the Society for
Environmental Exploration. Bent Otto Poulsen and Jon Fjeldsi of the Zoological
Museum of the University of Copenhagen provided valuable comments on the draft,
and the latter made helpful comments on the relative genetic ages of various bird
species. The paper was completed while NDB was employed by the Danish Centre
for Tropical Biodiversity, Copenhagen, Denmark (Grant nr. 1 1-0390).
REFERENCES
Alexander CS. 1969. Beach ridges in north-eastem Tanzania. 7?u Geograbhual Rariew 59: 104-122.
Andrews P, Groves CP, HorneJFM. 1975. Ecology of the Lower Tana floodplain (Kenya).Journal
of h East Ahcan Natural Histoty Socieg and National Museum 151: 1-31.
Archer AL, Collins S, Barnpton I. 1991. Report on a visit to Jozani Forest, Zanzibar. E a t A&an
Natural Histoy Sociep, Bulletin 21: 59-66.
Archer AL, Turner DA. 1993. Notes on the endemic species and some additional new birds occurring
on Pemba island, Tanzania. Scopus 16 94-98.
364
N. D. BURGESS ETAL.
Axelmd DI, Raven PH.1978. Late Cretaceous and Tertiary vegetation history of Africa. In: Werger
MJA, ed. Bwgeogaphy and Ecology of Southern Afnca. The Hague:Junk, 77-130.
Bennet KD. 1990. Milankovitch cycles and their effects on species in ecological and evolutionary
time. Paleobiology 16: 11-21.
Brenan JPM. 1978. Some aspects of the phytogeography of tropical Africa. Annals of the Missouri
Botanical Gaden 6 5 437478.
BrenanJPM, Exell AW, Fernandes A, Launert E, Wild H, eds. 1960-1983. Flora zambesiaca.
London: Academic Press.
Broadley DG, Howell KM. in press. Reptiles. In: Burgess ND, Clarke GP, eds. 77ze Coastal Forests
ofEastm AMa. Cambridge and Gland: IUCN.
Bruggen AV van. 1995. Biodiversity of the Mollusca: time for a new approach. In: Bruggen AC
van, Wells SM, Kemperman Th. CM, eds. Bwdimsi& and Consmation ofthe Mollusca. Proceedings of
the Alan S o h Memorial Spposiurn on thc bwdimsi& and conservation ofthe Mollusca. Oestgeest-Leiden,
Netherlands: Backhuys Publishers, 1-19.
Burgess ND, Mbwana S. in press. Forestry. In: Burgess ND, Clarke GP, eds. 77u Coastal Forests of
Eastern Afnca. Cambridge and Gland: IUCN.
Burgess ND, M& C, (eds.) 1994. Coastal Forests of Eastern Africa: Biodiversity and Conservation.
Unpublished report: London: The Society for Environmental Exploration and the University of
Dar es Salaam.
Burgess ND, Clarke GP, (eds.) in press. 77u Comtal Forests ofEastan Afnca. Cambridge and Gland:
IUCN.
Burgess ND, Stubblefield LK, Kweyunga C. in press a. Soils. In: Burgess ND, Clarke GP, eds.
l3e Coastal Forests OfEastm A h a . Cambridge and Gland: IUCN.
Burgess ND, Kock D,Cockle A, FitzGibbon C, Jenkins P, Honess P. in press b. Mammals.
In: Burgess ND, Clarke GP, eds. 77u Coastal Forests o f h t m Afnca. Cambridge and Gland: IUCN.
Burgess ND, FjeldsH J, Bottemeg R. in press c. The fauna of the Eastern Arc Mountains,
eastern Africa. 30~rnal
East Afncan Natural Hishy Sock&.
Chapman JD,White F. 1970.
Evergreen Forests ofMalawi. Oxford: Commonwealth Forestry
Institute.
Clark JD,Harris JWK. 1985. Fire and its roles in early hominid lifeways. 7 h Afncan Archaeological
Reuinu 3: 3-27.
Clarke GP. 1995. Status Reports for 6 Coastal Forests in Jindi Region, Tanzania. Unpublished
report: Frontier-Tanzania Technical Report No. 18. The Society for Environmental Exploration,
U.K./The University of Dar es Salaam, Tanzania.
Clarke GP. in press a. Defining the coastal forests. In: Burgess ND, Clarke GP, eds. 77ze Coastal
Forests o f h t m Afnca. Cambridge and Gland IUCN.
Clarke GP. in press b. Climate and microclimate. In: Burgess ND, Clarke GP, eds. 77ze Coastal
Fonsts ofEastan A@u. Cambridge and Gland IUCN.
Clarke GP. in press c. A new regional centre of endemism in Africa. In: Cutler DF, Huxley CR,
LockJM, eds. Aspects of h e ecology, tuxonomy and chomhgy ofthejloras ofAfnca and Madagascal: Km Bulletin
Additional Series. Kew: Royal Botanic Gardens.
Clarke GP, Dickinson A. 1995. Status Reports for 11 Coastal Forests in Coast Region, Tanzania.
Unpublished report: Frontier-Tanzania Technical Report No. 17. The Society for Environmental
Exploration, U.K./The University of Dar es Salaam, Tanzania.
Clarke GP, h m a JA. in press. History of anthropogenic disturbance. In: Burgess ND, Clarke
GP, eds. 77u Coastal Fonsts ofEastern Afnca. Cambridge and Gland IUCN.
Clarke GP, Stubblefield LK. 1995. Status Reports for 7 Coastal Forests in Tanga Region, Tanzania.
Unpublished report: Frontier-Tanzania Technical Report No. 16. The Society for Environmental
Exploration, U.K./The University of Dar es Salaam, Tanzania.
Clarke GP, Vollesen K, Mwasumbi LB. in press. Vascular plants. In: Burgess ND, Clarke GP,
eds. 77u Coastal Fonsts o f h t m Afnca. Cambridge and Gland IUCN.
Collar NJ, Stuart SN. 1988. Ky Fonstsfor nreatmed B i d in Afnca. ICBP Monograph no.3. Cambridge:
International Council for Bird Preservation.
Cooke HJ. 1974. The coastal geomorphology of Tanga, Tanzania. Ceoga#hical Review 6 4 515-535.
Cmnk QCB. 1997. Islands: stability, diversity, conservation. Special Issue: Bwdzvmsip and Conservation.
6 477495.
Crowe TM, Crowe AA. 1982. Patterns of distribution, diversity and endemism in Afrotropical birds.
J o u m l ofzoology, London 198: 41 7-442.
EASTERN AFRICAN COASTAL FORESTS
365
deMonocal PB. 1995. Plio-PleistoceneAfrican climate. Science 270: 53-58.
Diaz HF, Markgraf V, (eds.) 1992. El N8o: Hirtorical and Paleoclimatic Aspects ofthe Southern Oscillation.
New York Cambridge University Press.
Dowsett-Lemaire F. 1990. The flora and phytogeography of the evergreen forests of Malawi. 11.
Lowland Forests. Bulletin Jardin Botanique Nationale Bekque 60: 9-7 1.
East African Meteorological Department 1975. Climatological Stahticsfor East A h a , Part III,
Tanzania. Nairobi: East African Meteorological Department.
FitzCibbon CD, Leirs H, Verheyen W. 1995. Distribution, population dynamics and habitat choice
of the Lesser Pouched Rat, Beamys hindci (Rodentia: Cricetomyinae).30urnal of <oology, London 236:
499-5 12.
FjeldsBting;J. 1994. Geographical patterns for relict and young species in Africa and South America
and the dilemma of ranking biodiversity. Biodiversig and Consmation 3: 207-226.
Fjeldsi J, Lovett JC, (eds.) 1997. Biodiversity and environmental stability. Speczizl Issue: Biodiversig
and Consmation 6: 3 15-5 14.
Fjeldsi J, Lovett JC. 1997. Geographical patterns of young and old species in African forest biota:
the significance of specific montane areas as evolutionary centres. Special Issue: Biodiversig and
Consmation 6: 325-347.
Fjeldsi J, Ehrlich D, Lambin E, P M s E. 1997. Are biodiversity ‘hotspots’correlated with current
ecological stability? a pilot study using the NOAA-AVHRR remote sensing data. Special Issue:
Biodiversig and Conservation 6: 40 1423.
Freeman-Grenville CSP. 1967. The Coast, 1498-1840. In: Oliver R, Mathew G, eds. Hirto~yof
East A h a : the Earb Period. Nairobi: Oxford University Press.
Griffiths CJ. 1993. The geological evolution of East Africa. In: LovettJC, Wasser SK, eds. Biogeography
and Ecology ofthe Rain Forests ofEastem Afnca. Cambridge: Cambridge University Press, 9-23.
Giiffiths JF. 1972. Climate. In: Morgan WTW, ed. East Afnca: its Peoples and Resources, 2nd edition.
Nairobi: Oxford University Press, 107-1 17.
Hall M. 1984. Man’s historical and traditional use of fire in Southern Africa. In: Booysen P de V,
Tainton NM, eds. Ecological Effects of Fire. Berlin: Springer-Verlag.
Hamilton AC, Benstead-Smith R, (eds.) 1989. Forest Consmation in the East Usambara Mountains,
TanZania. Gland, Switzerland and Cambridge, U K IUCN.
Happold DCD. 1996. Mammals of the Guinea-Congolian rain forest. In: Alexander IJ
Swaine
,
MD,
Watling R, eds. Essqs on the Ecology o f t h e Guinea-Congo Rain Forest. Aoceedings ofthe Royal Sociep of
Edinburgh 104B, 243-285.
Hathout SA. 1972. Soil Resources of Tanzania. Dar es Salaam: Tanzania Publishing House.
Hawthorne WD.1993. East African coastal forest botany. In: LovettJC, Wasser SK, eds. Biogeography
and Ecologv ofthe Rain Forests ofEastem A h a . Cambridge: Cambridge University Press, 57-99.
Heywood VH, Watson RT, (eds.) 1995. Global Biodiversig Assessment. Published for the United
Nations Environment Programme by Cambridge University Press.
HofFman RL. 1993. Biogeography of East African montane forest millipedes. In: Lovett JC, Wasser
SK, eds. Biogeography and Ecology ofthe Rain Forests ofEastem Afha. Cambridge: Cambridge University
Press, 103-1 15.
HofFman RL. in press. Millipedes. In: Burgess ND, Clarke GP, eds. 7he Coastal Forests ofEastem
AJi2ca. Cambridge and Gland: IUCN.
Howell KM. 1993. Herpetofauna of the eastern African forests. In: Lovett JC, Wasser SK. eds.
Biogeography and Ecology ofthe Rain Forests ofEastem AJi2ca. Cambridge: Cambridge University Press,
173-201.
International Council €or Bird Preservation 1992. Putting Biodiversig on the Map: Prior$ Areas for
Global Consmation. Cambridge: ICBP.
Jong de R, Congdon TCE. 1993. The montane buttedies of the eastern African forests. In: Lovett
JC, Wasser SK, eds. Biogeography and E c o l o ~ofthe Rain Forests ofEastem Afnca. Cambridge: Cambridge
University Press, 133-1 73.
Kent PE. 1972. Mesozoic history of the east coast of Africa. Nutun 238: 147-148.
Kent PE. 1974. Continental margin of East Africa - a region of vertical movements. In: Burk CA,
Drake CL, eds. 7he Geology ofContinental Magins. New York Springer-Verlag, 313-320.
Kershaw M, Williams PH, Mace GM. 1994. Conservation of Afrotropical antelopes: consequences
and efficiency of using different site-selection methods and diversity criteria. BiOdiveriQ and Commation
3: 354-372.
Kielland-Lund J. 1988. Influence of grass fires on African landscape ecology. In: Mgeni ASM, Abeli
N. D. BURGESS ETAL.
366
WS, Chamshama SAO, Kokwero GS, eds. Aoceedirgs of a Joint Seminar/workrhop on ‘Management of
Natural Forests of Znzania’ under Soknine Universily of Agnculture and Agricultural Universip of Nomay
Coofieration. Morogoro: Sokoine University of Agriculture.
Kielland J, Cordeiro
in press. Butterflies. In: Burgess ND, Clarke GP, eds. 17re Coastal Forests
ofEast~mA h a . Cambridge and Gland IUCN.
King LC. 1978. The geomorphology of central and southern Africa. In: WergerJCA, ed. Biogeograophy
and Eology ofSouthem A@a. The Hague: Junk.
Kingdon J, Howell KM. 1993. Mammals of the forests of eastern Africa. In: Lovett JC, Wasser
SK, eds. Bwgeogr@hy and Ecolngy ofthe Rain Forests ofEastern A h a . Cambridge: Cambridge University
Press, 229-243.
Kjekshus HK. 1977. Ecological Conhl and Development in East Affia. Nairobi: Heinemann Educational
Books.
Lovett JC. 1988. Endemism and affinities of the Tanzanian montane forest flora. In: Goldblatt P,
Lowry PP, eds. Proceedings of the eleventh plenary meeting of the Association for the Taxonomic
Study of Tropical Africa. Monographs in &stmatic Bokmyhm the Missouri Botanical Gaden 25: 59 1-598.
Lovett JC. 1990. Classification and status of the Tanzanian forests. Mittdungen aus ae’ m Institut&r
Allgmkne Botanik Hambulg 23A 287-300.
Lovett JC. 1993a. Climatic history and forest distribution in eastern Africa. In: Lovett JC, Wasser
SK, eds. Biogeography and Ecohg ofthe Rain Forests ofEasfem A h a . Cambridge: Cambridge University
Press, 23-33.
Lovett JC. 1993b. Eastern Arc moist forest flora. In: Lovett JC, Wasser SK, eds. Biogeography and
Ecology ofthe Rain Forests ofEastem Ajhca. Cambridge: Cambridge University Press, 33-57.
Lovett JC. 1996. Elevational and latitudinal changes in tree associations and diversity in the Eastern
Arc mountains of Tanzania. 30unurl of Tmpical Ecology 12: 629-650.
Lovett JC, Wasser SK, (eds.) 1993. Biogeography and Ecologv of the Rain Forests of Eastern Ahca.
Cambridge: Cambridge University Press.
Lovett JC, Friis I. 1996. Patterns of endemism in the woody flora of north-east and east Africa. In:
van Maesen LJG, et al., eds. ’The Biodiversip ofAfican Plants. Kluwer Academic Publishers, 582-60 1.
Lovett JC, HansenJR, Herlyck V. in press. Comparison with the Eastern Arc Forests. In: Burgess
ND, Clarke GP, eds. 17re Coastal F m t s ofEastern Affia. Gland and Cambridge: IUCN.
Madgwick J, Wood B, Varty N, Maunder M. 1988. Somalia Research Project Report - an
Ecological Study of the Remaining Areas of Riverine Forest in the Jubba Valley, Southern Somalia.
Unpublished report: London: University College London.
Madgwick J. 1988. An ecological study of the remaining areas of riverine forest in the Jubba Valley,
southern Somalia. Brihih Ecological Socieo, Bulbtin 19: 19-24.
Mapa Florestal. 1980. Aovincia de Cabo Kklgado, Nampula, <ambecia, Beira, Inhambane, Gaza e Maputo.
Maputo: Ministerio da Agncultura do Florestal e de Fauna Bravia. Project0 UNDP-FAO.
Milne G. 1935. Some suggested units of classification and mapping, particularly for East African soil.
Soils Research 4: 183- 198.
Milne G. 1947. A soil reconnaissance through parts of Tanganyika territory, Dec. 1935-Feb. 1936.
Journal ofEcologv 35: 192-265.
Mlingwa COF, Waiyaki EM, Bennun L, Burgess ND. in press. Birds. In: Burgess ND, Clarke
GP, eds. 7he Coastal Forests OfEastrm A h a . Cambridge and Gland IUCN.
Moomaw JC. 1960. A Study of the Plant Ecologr of the Coast Region of Keya Cohry, East A h a . Nairobi:
Government Printer.
Miiller T. 1991. 7k Rainforests ofZimbabwe. Harare: National Herbarium.
Myers N. 1988. Threatened biotas: ‘hot spots’ in tropical forests. 7he Envimnmentalist 8: 187-208.
Myers N. 1990. The biological challenge: extended hot-spots analysis. ‘The Envimnmentalist 10: 243-256.
Philander SG. 1989. El .Mia, la Nt7a and the S o u h Oscillatwn. London: Academic Press.
Polhill RM, (ed.) 1952-. Flora of Tmpical East A h a . Rotterdam: AA Balkema.
Poynton JC. in press. Amphibians. In: Burgess ND, Clarke GP, eds. ‘The Coastal Forests ofEastern
A h a . Cambridge and Gland IUCN.
Prell WL, Hutson WHYWilliams DF, Be A m , Geitzenauer K, Molfino B. 1980. Surface
Circulation of the Indian Ocean during the Last Glacial Maximum, Approximately 18,000 yr. B.P.
Qaternay Research 14: 304-336.
Robertson SAYLuke WRQ. 1993. Kenya Coastal Forests: Report of the NMK/WWF Coast Forest
Survey. Unpublished report. Nairobi: World Wide Fund for Nature.
Rodgers WA, HallJB, Mwasurnbi LB, Griffiths CJ, Vollesen K. 1983. The Conservation
w.
EASTERN AFRICAN COASTAL FORESTS
367
Values and Status of Kimboza Forest Reserve, Tanzania. Unpublished report: Dar es Salaam:
University of Dar es Salaam Forest Conservation Working Group.
Rodgers WAYHomewood KM. 1982. Species richness and endemism in the Usambara mountains
forests, Tanzania. BiologicalJournal ofthe Linnean Sociep 18: 197-242.
Rodgers WAYMizray W, Shishra EK. 1985. The extent of forest cover in Tanzania using satellite
imagery. Uniuersio ofDar es Salaam Institute of Resource Assessment Research Paper 12: 1-15.
Rodgers WAYOwen CF, Homewood KM. 1982. Biogeography of East African forest mammals.
Journal of Biogeograpb 9: 4 154.
Rosenzweig ML. 1995. Species Diversip in Space and lime. Cambridge: Cambridge University Press.
Roy SM, SilvaJMC dayArctander P, Garcia-Moreno J, FjeldsH J. 1997. The role of montane
regions in the speciation of South American and African birds In: Mindell DP, ed. Avian Molecular
Evolution and Systaatics. London and New York Academic Press, 325-343.
Saket M. 1994. Report on the Updating of the Exploratory National Forest Inventory. Unpublished
report: Maputo: Ministry of Agriculture, Directorate of Forests and Wildlife.
Schmidt PR. 1989. Early exploitation and settlement in the Usambara Mountains. In: Hamilton
AC, ed. Forest Conservation in the East Usambara Mountains, Tanzania. Gland, Switzerland and Cambridge,
UK: IUCN.
Schmidt R. 1991. Ecology ofa Tmpical Lowland Rain Forest: Plant Communities, Soil Charackmdics and Nutrient
Relations ofthe Forests ofthe Shimba Hills National Reserve, Kenya. Berlin-Stuttgart:Dissertationes Botanic=,
Band 179.
Servicio Meteorologico Nacional 191%1951. Anais Meteomlogicos das Colonias. Volume V-XXXII Ano de 1918-1945. Direccao dos servicos diplomaticos geograficos e de marinha/Dirreccao tecnica
do foment0 (Reparticao do estudos geograficos)/Comissao de cartografia, Coimbra and Lisbon.
Sibley CG, Alquist JE. 1990. Ptyhgmy and the Clussfiation $Bids: a Study in Molecular Evolution. New
Haven, London: Yale University Press.
Stuart SN, Jensen FP, BmggePJensen S, Miller RI. 1993. The zoogeography of the montane
forest avifauna of eastern Africa. In: Lovett JC, Wasser SK, eds. Biogeography and Ecology of the
RainfDrests o f Eastern Ajhca. Cambridge: Cambridge University Press, 203-228.
SuttonJEG. 1990. A nousand Gars ofEast Ajhca. Nairobi: British Institute in Eastern Africa.
Timberlake J. 1994. Changes in the extent of moist forest patches in the eastern Highlands: case
studies based on aerial photographs. Zimbabwe Forestv Commission Research Paper 7: 1-15.
Vane-Wright RI, Humphries CJ, Williams PH. 1991. What to protect? Systematics and the
agony of choice. Biological Conservation 55: 235-254.
Vanzolini PE, Williams EE. 1981. The vanishing refuge: a mechanism for ecogeographical
speciation. Pap& Auulsos Zool. S. Paul0 34: 251-255.
Verdcourt B. in press. Molluscs. In: Burgess ND, Clarke GP, eds. 77te Coastal Forests ofEastern A h a .
Cambridge and Gland IUCN.
White F. 1979. The Guineo-Congolian Region and its relationships to other phytochoria. Bulletin
Jardin Botanique Nationale Belgtque 49: 1 1-55.
White F. 1983. 77ze Egetation ofAfica. Paris: UNESCO.
Williams PH, Humphries CJ. 1994. Biodiversity, taxonomic relatedness, and endemism in conservation. In: Forey PL, Humphries CJ, Vane-Wright RI,eds. Systematics and Conservation Evaluation.
Oxford: Clarendon Press, 269-287.
World Conservation Monitoring Centre (WCMC) 1992. Global Biodiuersip: Status ofthe Earthi
Living Resources. London: Chapman and Hall.
WWF & IUCN 1994. Centres o f Plant Diversi&: a Guide and Strate0 for their Conservation. Vol.1. Eumpe,
Ajhca, S W A s i a and the Middle East. Cambridge: IUCN Publications Unit.