Threats to the Evergreen Forests of Southern Malawi
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Threats to the evergreen forests of southern Malawi F. Dowsett-Lemaire and R. J. Dowsett Malawi has a large number of isolated highland forests on either side of the Rift Valley. While those in the north do not at present suffer from serious degradation, in the south several have been much encroached upon for fuel wood and land for cultivation. As a result localized birds, reptiles, butterflies and plant species are threatened. In a two-year exploration of the evergreen forests of the country conducted for the Forestry Department, the authors surveyed the distribu- tion and status of the flora and fauna, and identified threats to the survival of the rarer taxa. Malawi is a small country of enchanting and on the slopes of Mt Mulanje are (or were) most varied landscapes, with the greatest number extensive; 123 species of trees and woody (more than 40) of isolated mountain or hill forests shrubs have been recorded (Dowsett-Lemaire, in south-central Africa. Only one area, the Nyika 1988). There is an endemic tree Rawsonia Plateau in the north, is protected comprehen- (Dasylepis) burtt-dauyi and a semi-strangling sively within a national park. Most other forest patches are included in forest reserves, but their protection status depends more on local human demands for land and wood. The density of -14 human population is particularly high south of 9 N 14°S and endangers the survival of several local J \ \ .- \4 species of wildlife and plants. \ 1. i \ The vegetation -15 )•"•( Most of the forested hills in southern Malawi are / situated east of the Rift Valley formed by the i i /I r 6. Ti Shire River (Figure 1) and bear mid-altitude t 4 evergreen forests (Table 1). The flora was de- •' ^; -16 scribed in part by Chapman and White (1970), but the importance of medium-altitude forests | 0 100 Vv •'"*''' was overlooked. A more complete account of km the vegetation is in progress (Dowsett-Lemaire, °S \ ^ X. 1988 and unpub.). The wetter types of mid-al- -17 33 34 E 36 titude forest are dominated by 40-m tall New- 1 1 '} ° 1 tonia buchananii trees, and constitute a com- munity little studied and largely destroyed in the Figure 1. Map of southern Malawi showing the evergreen African tropics. Two of the finest examples of forests; shaded areas are lakes. Numbers refer to localities Newtonia forest occur on Chikala Hill and in the mentioned in the text: (1) Mt Mangochi; (2) Chikala Hill; (3) Mt Malosa and Mt Zomba; (4) southern Shire Ruo Gorge (Mulanje), with an interesting mixture Highlands including Lisau and Soche; (5) Mt Thyolo; (6) of lowland and Afromontane elements. Those Machemba Hill; (7) Mt Mulanje; (8) Malawi Hills. 158 Oryx Vol 22 No 3, Ju/y 1988 Downloaded from https://www.cambridge.org/core. IP address: 170.106.40.40, on 27 Sep 2021 at 15:14:40, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605300027782 Ficus so far unmatched; a new species of in the African Red Data Book (Collar and Stuart, Tapinanthus mistletoe was recently collected 1985) are marked with an asterisk below. from the upper Ruo Gorge. As a whole, the fern flora of the Mulanje forests is the richest in the The green barbet Stactolaema olivacea occurs country (over 100 species), with some in Malawi, as different subspecies, only in the Asplenium and Elaphoglossum spp. still to be Misukus (extreme north) and on Mt Thyolo. It named. There are two endemic Streptocarpus eats mostly figs, of which there is a noticeable lithophytes (S. dolichantus and S. milanijianus) abundance in these two forests. The distinctive and at least one endemic orchid [Polystachya subspecies on Thyolo, belcheri, is known other- sp. 1 in la Croix et a/., 1983). The small forest wise from one mountain in adjacent Mozam- on Mt Soche has an apparently endemic tree in bique (Namuli). its understorey, Buxus nyasica. The green-headed oriole Oriolus chloroceph- At higher altitudes, above 1500-1600 m, Afro- alus* is a sparsely distributed species in south- montane forests are comparatively impov- eastern Africa (Hall and Moreau, 1970). It was erished, but there is an interesting variant domi- mentioned in five localities by Benson and Ben- nated by tall Widdringtonia cupressoides on Mt son (1977), but in fact breeds in just two forest Mulanje, this cedar being at the northern limit areas in southern Malawi: on Chikala Hill (c. 15 of its range (Edwards, 1985; Dowsett-Lemaire, pairs) and Thyolo (including lowland forest on 1988). the tea estates, 40-45 pairs). Recent records on Lisau are of passage birds; there have been no acceptable records on Mt Soche since the 1940s; The wildlife the forest on Namzadi Estate no longer exists. The bird distribution in Malawi is described by Benson and Benson (1977), and the butterflies The Thyolo (Cholo) alethe Alethe choloensis* by Gifford (1965). As with the vegetation, many was found in all the mid-altitude and submon- new distribution records were obtained during tane forests of the south (east of the Rift). It is our survey. Nevertheless, several bird and but- almost endemic to Malawi, as it is otherwise terfly species are extremely localized and their known from only two mountains in adjacent survival is threatened. The birds that are included Mozambique (Collar and Stuart, 1985). Overall numbers in Malawi are in the order of 1500 Table 1. Main features of the evergreen forests of southern pairs. It is locally common in several forests, Malawi mentioned in the text especially on Mt Thyolo (c. 200 pairs) and mid- altitude Mulanje (c. 1000 pairs in 1984). Locality Altitude (m) Forest type Size (ha)* The spotted thrush Turdus fischeri* has a very localized distribution in Africa (Collar and Stuart, MtMangochi 1550-1700 Submontane 230 1985). The Malawi endemic race belcheri is ChikalaHill 1300-1600 Mid-altitude 285 Shire Highlands: known from just four forest localities: Lisau, MtMalosa 1700-1950 Submontane 730 Soche, Mt Thyolo and the slopes of Mt Mulanje. MtZomba 1600-1950 Submontane 600 Its overall numbers are very low—some 30 to Lisau Saddle 1300-1450 Mid-altitude 160 (Chiradzulu) 40 pairs. Mt Soche 1300-1520 Mid-altitude 150 Mt Thyolo 1200-1450 Mid-altitude 1000 The white-winged apalis Apalis choriessa* is pre- Thyolo tea sently recorded from 11 mid-altitude forests, in estates c. 1050 Lowland 600 Machemba Hill 1150-1300 Lowland 40 some of which it is common (especially Lisau). Mt Mulanje It is otherwise known from forests in Kenya (1), (incl.Mchese): Tanzania (2) and Mozambique (1), and may now Lower slopes 600-950 Lowland c.200 Middle slopes 900-1500 Mid-altitude 1800 be extinct in Kenya. It is threatened through its Upper slopes 1500-1850 Submontane j 5000 prime habitat being riparian or secondary Albizia and plateaux 1850-2300 Montane / forests in the Shire Highlands, which are under Malawi Hills 600-900 Lowland 400 heavy human pressure. Total numbers are not *Sizes are measured from aerial photographs. much above 100 pairs. Southern Malawi: evergreen forests 159 Downloaded from https://www.cambridge.org/core. IP address: 170.106.40.40, on 27 Sep 2021 at 15:14:40, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605300027782 Figure 2. Large tracts of Chinsongeli Forest, Mt Mulanje, have been cleared for the planting of annual food crops. Some 14 forest-associated butterflies are appar- Mulanje. Another chameleon Rampholeon ently endemic to Malawi, of which eight occur platyceps appears endemic to the forests of in the south, with three only on the slopes of southern Malawi, from Mulanje and Zomba to Mt Mulanje: the lycaenids Alaena lambomi, A. the Malawi Hills (Loveridge, 1953; Hargreaves, ochracea and Baliochila woodi (Mulanje); the 1979). nymphalids Charaxes margaretae (Mulanje), C. martini, C. chinteche (north also), Cvmothoe The conservation status of the zombana and C. melanjae (Mulanje). evergreen forests All forest remnants but one (on Machemba Hill The forests are too small to contain many species where the forest is being felled) are included in of large mammals. The blue monkey Cerco- forest reserves. However, the increasing human pithecus albogularis is still common locally, as population is placing timber and firewood is a forest antelope, the blue duiker Cephalophus supplies under severe pressure in most places. monticola. Hunters have exterminated in places On the Mulanje slopes, forest is also cleared for bushbucks Tragelaphus scriptus and bushpigs subsistence cultivation: many of the estate work- Potamochoerus porcus. ers have insufficient land for gardens at lower Among other vertebrates, an endemic chame- levels, and there is also an influx of squatters leon Chamaeleo mlanjensis (Broadley, 1965) from war-torn Mozambique. As a result, all low- and an endemic subspecies of frog Arthrolepis land and mid-altitude forests remaining on adolfifriederici francei (Stewart, 1967) are con- Mulanje are seriously threatened. For example, fined to rain forest along the Ruo River on Chisongeli Forest, on the south-eastern slopes, 160 Oryx Vol 22 No 3, July 1988 Downloaded from https://www.cambridge.org/core. IP address: 170.106.40.40, on 27 Sep 2021 at 15:14:40, subject to the Cambridge Core terms of use, available at L.https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605300027782 Figure 3. Mt Thyolo, with the hill forest eaten into by cultivated land; tea and Eucalyptus plantations in the foreground. extended from 900 to 1800 m, and aerial photo- been steadily encroached upon for gardens in graphs show that it still covered 40 sq km in the past 20 years (Figure 3).