Neil Burgess, Jon Lovett and Shakim Mhagama, Uluguru Mountains ..... and there is some evidence for a decline in rainfall and clouds (Hamilton 1998). In the.
BIODIVERSITY CONSERVATION AND SUSTAINABLE FOREST MANAGEMENT IN THE EASTERN ARC MOUNTAINS Neil Burgess, Jon Lovett and Shakim Mhagama, Uluguru Mountains Biodiversity Conservation Project, P.O. Box 312, Morogoro, Tanzania Draft paper for Dr. Felician Kilahama and the GEF Eastern Arc Strategy Background The Eastern Arc comprises the ancient crystalline mountains that run from the Taita Hills in Kenya to the Makambako Gap just to the south-west of the Udzungwa Mountains, Tanzania (figure 1; table 1), and that are under the direct climatic influence of the Indian Ocean (Lovett, 1990). These mountains support forest and some grassland and heathland vegetation, although large areas have been converted from natural vegetation to agriculture and plantations. There is a chain of somewhat similar montane forest areas extending from southern Tanzania to Malawi, Mozambique and Zimbabwe. However, these more southern forests are not so directly under the Indian Ocean climatic regime, are subject to more variable convectional rainfall patterns, and the forests do not possess the species richness and endemism of the Eastern Arc. Together, the Eastern Arc and these other montane forest areas comprise the Tanganyika-Nyasa Mountain Forest Group (Moreau, 1966). The Eastern Arc Mountains rise from the coastal plain to 2,635 m in altitude at their highest point (Kimhandu Peak in the Ulugurus). Above about 2200 m the vegetation is elfin woodlands/forests, montane grasslands and bogs. Forest extends downwards from the frost line at c. 2,400 m to the base of the mountains at around 300 m (except where the lower slopes have been cleared). In undisturbed forest the change in species composition is continuous (Lovett, 1998), but for convenience the forest formations have been divided into upper montane (1,800–2,635 m), montane (1,500–1,800 m) and sub-montane (800–1,500 m) forest (e.g. Pócs, 1976a, b; Lovett, 1993). At lower altitudes (regarded by Pócs, 1976a, b as below 800 m) the forest grades in species composition and physiognomy into that of the lowland Coastal Forests, found along the eastern seaboard of Africa from Somalia in the north to Mozambique in the south (Burgess & Clarke, 2000). Table 1. Location, area, and altitudinal range of forested habitats in the Eastern Arc Mountains Sites Taita Hills 1, 13 North Pare 2, 3 South Pare 2 West Usambara 4, 5 East Usambara 3, 4, 5, 9 Nguu 10 Nguru 2 Ukaguru 2, 11 Rubeho 7 Uluguru 2, 8 Malundwe Hill 12 Mahenge 2 Udzungwa 2, 6
Coordinates (degree and minutes) 0325S 3820E 0335–0346S 3733–3740E 0404–0434S 3745–3801E 0420–0507S 3806–3841E 0445–0520S 3826–3848E 0527–0538S 3736–3732E 0527–0613S 3726–3737E 0619–0635S 3653–3703E 0648–0722S 3634–3658E 0651–0712S 3736–3745E 0724S 3718E 0837–0838S 3642–3644E 0722–0843S 3507–3658E
Forest area (km²) 3 25 211.1 220 450 140.42 328.35 155.38 654 291 4.5 5 1017
Distance to coast (km) 165 220 150 100 50 150 150 220 300 180 270 300 300
Altitudinal range of forest (m) 1500–2140 1300–2113 820–2463 1200–2200 130–1506 1000–1550 400–2000 1500–2250 520–2050 300–2400 1200–1275 460–1040 300–2580
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1: Waiyaki, unpublished; 2: Lovett & Pócs (1993); 3: Cordeiro & Kiure (1995); 4: Iversen (1991); 5: Evans (1997); 6: Moyer (1992); 7: Fjeldså et al. (1997); 8: Svendsen & Hansen (1995); 9: Johansson and Sandy (1996); 10: Seddon et al. (1995); 11: Evans & Andersen (1992); 12: Lovett & Norton (1989); 13: Tetlow (1987); 14: Lovett et al. (in press).
Details of the Eastern Arc Mountain blocks (Table 1, Figure 1) show that the mountains generally contain a small area of forest, isolated from other similar forests, and that the altitudinal extent of the forest is quite variable. In many cases the lower margins of the forest are cleared for agriculture and only the forest on the higher parts of the mountains (in reserves) persists. Biological Values of the Eastern Arc. The Eastern Arc has long been recognised as an important area for biodiversity (Polhill, 1968; Rodgers & Homewood, 1982), and achieved national recognition in the Tanzania Forest Action Plan as a key conservation component (Bensted-Smith & Msangi, 1989). The reason for the biological uniqueness of the Eastern Arc appears to be the exceptionally long period of relative climatic stability on the tropical east African coast (Lovett and Friis, 1996). The forests may be in the region of 30 million years old. The Eastern Arc has also been identified as a global priority area for the conservation of birds in the analysis undertaken by BirdLife International (Stattersfield et al. 1998). Together the Eastern Arc and the adjacent lowland Coastal Forests of eastern Africa are classified as the Eastern Arc/Coastal Forests Biodiversity Hotspot by Conservation International (Mittermeier et al. 1998; 1999; Myers et al. 2000). They are therefore one of the top 25 areas in the world for the conservation of endemic plants. Moreover, in the analysis of priority ecoregions based on birds, mammals, reptiles, amphibians and plants the Eastern Arc and the adjacent lowland coastal forests have both been recognised by World Wildlife Fund (USA) as being of global significance (Olson and Dinerstein, 1998; Burgess et al. in prep). The biodiversity values of the Eastern Arc, according to our current understanding, are summarised in Lovett and Wasser (1993) and Burgess et al. (1998). The biological data presented here is derived from those publications, and also from biological databases of the University of Copenhagen in Denmark, and the University of York in the UK. New species are still being discovered regularly where-ever intensive biological studies are undertaken. For example the Kihansi Spray Toad was only discovered in 1996 during environmental monitoring work for the Lower Kihansi Hydropower Project in the southern Udzungwa mountains (Poynton et al., 1998). At least 74 vertebrate species are strictly endemic to the Eastern Arc Mountains, split as follows: birds 10 species, mammals 11 species, reptiles 23 species and amphibians 30 species. A further 40 species are near-endemics, but range slightly more widely than the strict definition of the Arc. Eastern Arc Mountain blocks that possess endemic vertebrates are the Taita Hills (two species), the East and West Usambaras (12 species), the Ngurus (one species), the Ulugurus (13 species) and eastern Udzungwas (13 species).
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A minimum estimate of 265 invertebrate species confined to single Eastern Arc Mountain blocks has been obtained, although insufficient collection and taxonomic work means that this figure is certainly an gross underestimate. Work on a few invertebrate groups in the Uluguru Mountains has discovered 169 invertebrate species endemic to that mountain alone. There are an estimated 4000 plant species in the Eastern Arc and Coastal Forest biodiversity hotspot, of which 1500 are endemic (Myers et al., 2000). Most of the endemics are found in the herbs and shrubs, but in the trees a total of 223 endemic tree species have been recorded from the Eastern Arc (Lovett et al. in press) of which 66 are large canopy trees (Lovett 1998; Appendix 2). Although most endemic species are closed-forest specialists, there are Eastern Arc endemic birds and butterflies in montane grasslands and heathlands. Similarly, endemic plants occur throughout the elevational range of the Eastern Arc forests and are represented by all growth forms from tiny saprophytes to large canopy trees. They are also found on rocky outcrops, upland grassland and heaths where these are due to natural processes and are not the result of human disturbance. The most important locations for the conservation of biodiversity are the east-facing scarps directly influenced by the Indian Ocean in the largest highlands. Of these the most important on current data are the Udzungwas, the Ulugurus and the East Usambaras. In comparison the North and South Pare Mountains, Rubehos and Ukagurus seem genuinely poorer in endemics than other areas (Figure 2). However, even these less species rich mountains contain significant levels of endemic species. Management of Biodiversity in the Eastern Arc Mountains There are a number of issues relating to biodiversity conservation that also affect the options available for sustainable management of the Eastern Arc forests. Some of the major issues to be considered are summarised below. Habitat distribution of the endemic species in the Eastern Arc Mountains Data compiled for birds, mammals and amphibians indicate that most Eastern Arc endemic species are confined to dense forest habitats. For the mammals and amphibians 100 % of the known endemic species are dense forest specialists, which are only able to tolerate a little forest disturbance (Schiøtz 1976; Kingdon and Howell, 1993). These data are summarised in Appendix 1. The situation is less clear cut for the invertebrates and plants endemic to the Eastern Arc. For the plants there are a large number of endemic species that are found in the upland grasslands, bogs and on rocky areas. Also for the butterflies, there are endemic species of the montane grasslands, and these have been quantified by de Jong and Congdon (1993). These authors demonstrated that of the Eastern Arc endemic butterflies, 60% were found in forest and 30% in grasslands and other open areas. Hence all the natural habitat types remaining on the Eastern Arc Mountains have biological value, but it is the forests that have the highest importance.
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Ability of biodiversity to withstand habitat alteration in the Eastern Arc Mountains A key question for the sustainable management of the Eastern Arc forests is whether the endemic species are able to tolerate disturbance of their habitat. Although there is not much data collected on this issue, what is known seems to indicate that the heavily disturbed areas of forest (by human use) have a lower number of the endemic species than nearby undisturbed forests. For example, where there is forest disturbance many of the Eastern Arc amphibians species are replaced by more widespread forest edge or ‘farmbush’ species (Schiøtz, 1981). The same seems to be true of many endemic forest birds which are not found in heavily disturbed areas, or their populations are reduced (Fjeldså, 1999). Moreover, Lovett (1999) and Lovettt et al. (in press) have also found the same general picture for plants of the Eastern Arc, in that the disturbed forest areas have a lower number of the endemic species than the undisturbed areas e.g. Table 2, Lovett 1999). Table 2. Comparison of numbers of species and endemism in samples of 60 trees from four montane forests in the Eastern Arc mountains of Tanzania. The 60 tree sample was obtained by combining three 20-tree plots. The plots from the Southern Udzungwa mountains are from forest which has regenerated over old cultivation. These plots are composed of widespread species with no Eastern Arc endemics (from Lovett 1999). Eastern Arc Block West Usambara Southern Nguru Northern Udzungwa Southern Udzungwa
Species 26 21 20 9
Endemics 5 4 6 0
This is also true for the lowland coastal forests where limited data indicates that disturbed forests tend not to possess the coastal forest endemic plant species (Mwasumbi et al. 1994). Hence, although there have been only a few studies on this issue, all of them indicate that the disturbed forest areas are of lower biodiversity value than the undisturbed ones. Questions such as how much disturbance can be tolerated by different species, how does selective pole cutting or timber harvesting affect the biodiversity values, etc have no answer at the present time and are worthy subjects for further study. The threat status of the species in the Eastern Arc Mountains The Red Data Books compiled by the World Conservation Union (e.g. IUCN 1997; Hilton-Taylor, 2000) provide a measure of the degree to which the species of the Eastern Arc Mountains are currently threatened with extinction. If many of the Eastern Arc species are found in the Red Data Books, or if the number is increasing, then this can be taken as a measure of the pressure on the species remaining here and the extinction risk within this ecosystem. In the Eastern Arc there are 15 birds and 22 mammals on the 2000 Red List of Threatened Species (Table 3). There have been some additions to the Red List since 1997, for example the Eastern Arc near-endemic species the Abbotts Duiker Cephalophus spadix has been added to this list. Clearly this is a worrying trend and indicates that the threats to species are increasing.
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Table 3: Red Data Book Birds and Mammals found in the Eastern Arc Mountains of Tanzania (from Hilton-Taylor, 2000). Taxon Group
Species Name
Status of threat
Bird Anthreptes pallidigaster EN B1+2abce Bird Anthreptes rubritorques VU B1+2abce Bird Bathmocercus winifredae VU B1+2abce Bird Bubo vosseleri VU B1+2bce Bird Hyliota usambarae EN B1+2abce Bird Modulatrix orostruthus VU B1+2abce Bird Nectarinia rufipennis VU B1+2c Bird Orthotomus moreaui CR C2a Bird Ploceus nicolli EN C2a Bird Sheppardia gunningi VU B1+2abce Bird Sheppardia lowei VU B1+2abce Bird Sheppardia montana EN B1+2abce Bird Swynnertonia swynnertoni VU B1+2bce Bird Xenoperdix udzungwensis VU D2 Bird Zosterops winifredae VU C2b, D2 Mammal Beamys hindei VU A1c Mammal Cephalophus spadix VU C1 Mammal Cercocebus galeritus ssp. sanjei EN B1+2abcde Mammal Colobus angolensis ssp. palliatus DD Mammal Crocidura desperata CR B1+2c Mammal Crocidura tansaniana VU B1+2c Mammal Crocidura telfordi CR B1+2c Mammal Crocidura usambarae VU B1+2c Mammal Dendrohyrax validus VU B1+2c Mammal Diceros bicornis CR A1abc Mammal Galago orinus DD Mammal Kerivoula africana DD Mammal Loxodonta africana EN A1b Mammal Malaconotus alius EN B1+2abce Mammal Myonycteris relicta VU A2c Mammal Myosorex geata EN B1+2c Mammal Paraxerus palliatus VU A1c Mammal Paraxerus vexillarius VU B1+2c Mammal Procolobus gordonorum VU B1+2abcde Mammal Rhynchocyon petersi EN B1+2c Mammal Rhynchocyon cirnei VU B1+2c Mammal Sylvisorex howelli VU B1+2c Key: CR=Critically endangered, EN=Endangered, VU=Vulnerable, DD=Data deficient.
The species of reptiles and amphibians have not yet been assessed to determine their extinction risk, but it is likely that all of the strict endemic species listed in Appendix 1 would feature on such a ‘Red List’. Several studies have also used the Red Data Book lists to investigate risks for extinction of species. It has been shown that there is a lag time following the loss of habitat, and the number of species threatened with extinction, or which become extinct (e.g. Brooks et al., 1999). It is possible to estimate the number of species that might become extinct if there is any more loss of habitat. Brooks et al. (in press) have done this for the Conservation International Hotspot areas of the world and for the Eastern Arc Mountains and Coastal Forests combined they estimate that if there is a 1000 sq km loss of habitat, then 120 species of plants and 10 species of animals would become 5
extinct. This is the highest predicted extinction for any of the 25 Hotspots around the world. Of course it is not expected that 1000 sq km of forest and upland grasslands are lost in the Eastern Arc, but even small additional habitat losses can cause extinction. Climatic change in the Eastern Arc Mountains Another factor which affects the planned management strategy for the biodiversity and forest resources of the Eastern Arc Mountains is the affects of global or local climatic changes. On biogeographic evidence it appears that the Eastern Arc climate has remained relatively stable throughout an exceptionally long period of time. It is possible that the climate may continue to be fairly stable, even in the face of potential global climate has change due to mans influence. However, there is also evidence of smaller scale changes in the climate of areas such as the Eastern Arc Mountains, which might be due to global climate changes, to natural cycles in the climate of eastern Africa, or to the effects of human alteration of the habitat on these mountains, specifically deforestation. There is some evidence from East Usambaras, Ulugurus and Udzungwas that the climate of these mountains has become drier and warmer over this century. In the East Usambaras coconut trees can now grow at Amani, where they previously could not, and there is some evidence for a decline in rainfall and clouds (Hamilton 1998). In the East Usambaras, Ulugurus and Udzungwas the montane forest tree species Octoea usambarensis is not regenerating, which may indicate a climatic change. In all areas there are many stories that the cloud cover on the mountains has reduced, the climate become warmer and the rainfall declined, especially in the short rains and during the long dry season. However, the data are generally lacking to substantiate these claims. Status of the forest Habitat in the Eastern Arc Mountains The status of the forest cover in the Eastern Arc Mountains has never been totally assessed, although reasonable data have been compiled using the land cover maps of 1996 (Newmark 1998; Table 4), and through consideration of expert opinion (Burgess et al. 1998). Both approaches arrived at broadly the same conclusions about the amount of forest remaining. The number of forest patches has also been quantified as one measure of the fragmentation of the natural forest cover, and an estimate of the loss of forest historically has also been attempted. On average it is estimated that the Eastern Arc Mountains have already lost 73% of their potential forest cover (Table 4). Table 4. Description of forest cover in the Eastern Arc Mountains (reproduced from Newmark, 1998) Eastern Arc Mountain Taita Hills North Pare South Pare West Usambara East Usambara Nguru Ukaguru
Natural forest (km2)
Number of forest patches
Closed forest (km2)
Loss of original forest cover (%)
6a 151 333 328 413 647 184
13 2 5 17 8 8 1
4a 28b 120c 245d 235e 120f 100f
98 50 73 84 57 82 90
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Uluguru Rubeho Mahenge Udzungwa a. b. c. d. e. f. g. h. i.
527 499 291 1960
5 6 3 26
120f 100g 63h 389i
65 37 89 76
Source: personal communication, L. Lens. Source: personal communication, N. Cordeiro. Source: personal communication, W. Stanley. Source: Stuart (1983). Source: Johansson & Sandy (1996). Source: Collar & Stuart (1988). Source: Fjeldså et al. (1997). From Forest Reserve area data in Lovett and Pócs (1993). Source: Rodgers & Homewood (1982); Moyer (1992).
Forest losses have been quantified in more detail in the Uluguru Mountains where plots of estimated and known forest cover indicate that the mountain has lost at least 60% of its potential forest cover (Figure 3), which is in close agreement with the estimates in Newmark 1998 (Table 4). Importance of the loss of sub-montane forest in the Eastern Arc Mountains In the Eastern Arc Mountains the loss of forest outlined above does not proceed evenly with increasing altitude. On these mountains the higher altitude areas of forest are typically found within Catchment Forest Reserves, and only some of the areas of forest have been protected in this way on the lower slopes. This has meant that the majority of the forest loss in the Eastern Arc has occurred in the lowland and lower parts of the sub-montane forests up to around 1000 m altitude. The altitudinal loss of forest across the Eastern Arc is not quantified, but for the Uluguru Mountains this loss between 1955 and 1977 has been assessed (see Figure 4). This figure shows how the total area of forest between 500 and c.1600m has been the most converted, with very little conversion occurring above 1900 m (which is all reserved). The loss of the sub-montane forest to farmland may drive some species to extinction as different plants and animals are found only in certain altitude bands. In order to illustrate this altitudinal data on the plants and animals of the Ulugurus has been compiled and shows that more than 50 of the Uluguru strict endemic (only found in the Ulugurus) plants and 7 of the Uluguru strict endemic animals are found in the submontane forests. With the loss of these forests then these species become more threatened with extinction. To illustrate this, in the past two Eastern Arc endemic bird species were found in the Ulugurus, Tanzanian Mountain Weaver and Banded Green Sunbird, which are no-longer present. These are both species preferring the submontane forest. Moreover, an endemic snake species Prosymna ornatissima, which was found in the sub-montane forest in the 1920s, has not been relocated in recent years. This species might now be extinct. Of course it is hard to prove that a species has really become extinct on the Ulugurus, but these are clues that there are problems and that species might be disappearing without this being recorded. Changes in the hydrological role in the Eastern Arc Mountains The Eastern Arc forests are extremely important catchment areas for Tanzanian water supplies. For example, the Ruvu River comes from the Ulugurus, the Pangani River 7
comes in part from the Pare, West Usambara and East Usambara Mountains (as well as Kilimanjaro), the Sigi River comes from the East Usambaras, the Wami River comes from the Nguru, Ukaguru and Rubeho Mountains, the Great Ruaha and Kilombero Rivers that join the Rufiji come from the Udzungwas. It is clear from this list that most of the major rivers in eastern Tanzania come from these mountains and hence most of the towns and townspeople depend on their water. Moreover, the electricity generating capacity of Pangani Falls, Mtera Dam, Kidatu Dam and Kihansi also depends on the water that falls on these mountains. Studies in the 1970s (Pócs 1974, 1976) illustrated how the mossy forests of the higher altitude portions of the Ulugurus were able to capture water from clouds and hold that water, releasing it slowly. This ability of forests, especially ones covered with epiphytic plants to gather water from clouds and then pass this water gradually to water courses was recognised over 100 years ago in Tanzania. Simply living next to these mountains gives an idea of how the process works. The cloud base in the Ulugurus is generally just above the straight line of the reserve marking the border between forest and farmland. Move the boundary upwards through deforestation (as in the Kitundu Hills in the Ulugurus) and the cloud base moves upwards. The forest can capture the water from the clouds, but if the clouds are gone then this is no-longer possible. Deforestation will change the cloud patterns and is a probably explanation of many of the local stories about the short rains becoming less frequent and the area being hotter and drier in the past. This general situation is believed to hold true for all the other areas of the Eastern Arc as well. Implications for sustainable forest management in the Eastern Arc Mountains The implications for the management of the Eastern Arc Mountains are as follows: -
-
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The forests and to a lesser extent the upland grasslands of the Eastern Arc Mountains contain exceptional numbers of endemic plants and animals, making the area of global importance for the conservation of biodiversity. In terms of the area of habitat remaining and the number of endemic species the Eastern Arc is calculated to have the highest density of strictly endemic species in the world (Myers et al. 2000). Around 75% of the original forest cover of the Eastern Arc has been lost, mainly to subsistence agriculture. This loss is continuing and in most places the forest is now confined to the Catchment and Local Authority Forest Reserves. A few villages also have forest reserves or unreserved forest patches but these are typically small and many are still being cleared for farmland. Forest loss in the Eastern Arc Mountains has not been even. Typically the lower altitude portions of the forest have been lost, while the highest altitude portions still remain. This loss of the lower forests will have affected the biodiversity, climatic and catchment values of the Mountains. Methods are available to predict the number of species which are likely to be threatened by extinction with additional forest loss, and these calculations have already been made for the combined Eastern Arc and Coastal Forests ecoregions. There is a timelag between deforestation and extinction and species still surviving in the Eastern Arc may yet become extinct due to the habitat destruction that has already occurred.
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Where the forests are disturbed by human activities then there is a reduction in the biodiversity values. Rare and endemic species are replaced by species found over a much greater portion of Africa. Forest utilisation therefore poses a threat to the conservation of biodiversity in the Eastern Arc. However, the levels of utilisation, which can be tolerated by the endemic species, is not known. Although it is difficult to prove, circumstantial evidence indicates that climates have warmed, cloud-bases have moved higher up the hills and hence the catchment values of the eastern Arc Mountains have probably declined. All of the Eastern Arc blocks report these phenomena, but there are no hard data to either prove or disprove their effects on the catchment values of the forests. In conclusion the habitats of the Eastern Arc are of exceptional global and national value for biodiversity and water catchment, but these values may have been degraded over the past decades through forest loss and forest degradation. As the forests are mainly found in the Catchment Forest Reserves managed by the Forestry and Beekeeping Division then the role of this body is critical for the long-term future of the forests. We recommend that the reserves are maintained for the national and global interests under central government control, but that mechanisms such as project trust funds, water levies, and biodiversity funds are used to maintain and even improve the integrity of the reserves. Expansion of the existing forest cover is also recommended in order to reverse some of the deforestation that has been going on for hundreds of years and even accelerating over the past decade.
Acknowledgements Part of this paper is derived from the Eastern Arc Conference Proceedings (conference 1997, published 1998). The authors wish to thank the staff of the Uluguru Mountains Biodiversity Conservation project for provision of some of the data and ideas contained in this paper. FBD are also thanked for the opportunity to submit this paper to the GEF process for the Eastern Arc Mountains.
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Lovett, J.C. & T. Pócs (1993). Assessment of the Condition of the Catchment Forest Reserves, a Botanical Appraisal. Catchment Forest Project: Ministry of Tourism, Natural Resources and the Environment, Dar es Salaam. Lovett, J.C. & S.K. Wasser (eds) (1993). Biogeography and Ecology of the Rain Forests of Eastern Africa. Cambridge University Press, Cambridge. Lovett, J.C. & I. Friis (1996). Some patterns of endemism in the tropical north east and eastern African woody flora. Pp. 582-601. In: van der Maesen, L.J.G., X.M. van der Burgt & J.M. van Medenbach de Rooy (eds.). The Biodiversity of African Plants. Proceedings XIVth AETFAT Congress 22-27 August 1994, Wageningen, The Netherlands. Kluwer Academic Publishers, Dordrecht. Lovett, J.C., Clarke, G.P. Moore, R. & Morrey, G. (In press). Elevational distribution of restricted range forest tree taxa in eastern Tanzania. Biodiversity and Conservation. Moreau, R.E. (1966). The Bird Faunas of Africa and its Islands. Academic Press, London. Moyer, D. (1992). Report on the natural resources consultancy for the Udzungwa Forest Management Plan Project Preparation Mission. Forest and Beekeeping Division/DANIDA, Dar es Salaam. Mittermeier, R.A., Myers, N., Gil, P.R. & Mittermeier, C.G. (1999). Hotspots: earth’s biologically richest and most endangered terrestrial ecoregions. Mexico City: CEMEX. Mittermeier, R.A., Myers, N., Thompsen, J.B., da Fonesca, G.A.B. & Olivieri, S. (1998). Global biodiversity Hotspots and Major Tropical Wilderness Areas. Conserv. Biol. 12: 516-520. Mwasumbi, L.B., Burgess, N.D. and Clarke, G.P. (1994). Flora of Pande and Kiono coastal monsoon forests, Tanzania. Vegetatio 113: 71-81 Myers, N., Mittermeier, R.A., Mittermeier, C.G., da Fonseca, G.A.B., Kent, J. (2000). Biodiversity hotspots for conservation priorities. Nature 403: 853-858. Newmark, W. (1998). Forest area, fragmentation and loss in the Eastern Arc Mountains: implications for the conservation of biological diversity. Journal of the East African Natural History Society 87: 29-36. Olson, D.& Dinerstein, E. (1998). The Global 200: a representation approach to conserving the Earth’s most biologically valuable ecoregions. Conserv. Biol. 12: 502-515. Pócs, T. (1974). Bioclimatic studies in the Uluguru Mountains (Tanzania, East Africa) I. Acta Botanica Academiae Scientarium Hungaricae 20: 115-135. Pócs, T. (1976b). Vegetation mapping in the Uluguru Mountains (Tanzania, East Africa). Boissera 24: 477–498. Pócs, T. (1976b). Vegetation mapping in the Uluguru Mountains (Tanzania, East Africa). Boissera 24: 477–498. Polhill, R.M. (1968). Tanzania. In Hedberg, I. & O. Hedberg (eds): Conservation of Vegetation in Africa South of the Sahara. Acta Phytogeographica Suecica 54: 166–178. Poynton, J.C., Howell, K.M., Clarke, B.T. & Lovett, J.C. 1998. A critically endangered new species of Nectophrynoides (Anura: Bufonidae) from the Udzungwa mountains, Tanzania. African Journal of Herpetology 47(2): 59-67. Rodgers, W.A. & K.M. Homewood (1982). Species richness and endemism in the Usambara mountains forests, Tanzania. Biological Journal of the Linnean Society 18: 197–242. Schiøtz, A. (1976). Zoogeographical patterns in the distribution of East African treefrogs (Anura: Ranidae). Zoologie Africaine 11: 335–338. Schiøtz, A. (1981). The Amphibia in the forested basement hills of Tanzania: a biogeographical indicator group. African Journal of Ecology 19: 205–207. Seddon, N., D.R. Capper, J.M. Ekstrom, I.S. Isherwood, R. Muna, R.G. Pople, E. Tarimo & J. Timothy (1995). Project Mount Nilo ’95: a bird conservation project to the East Usambara and Nguu Mountains, northern Tanzania. Cambridge University Expedition Reports, Cambridge. Stattersfield, A.J., M.J. Crosby, A.J. Long & D.C. Wege 1998. Endemic Bird Areas of the World: Priorities for Biodiversity Conservation. BirdLife Conservation Series No. 7. BirdLife International, Cambridge, UK. Svendsen, J.O. & L.A. Hansen (eds) (1995). Report on the Uluguru Biodiversity Survey, 1993. The Royal Society for the Protection of Birds, Danish Centre for Tropical Biodiversity and Tanzania Forestry Research Institute, Sandy. Tetlow, S.L. (1987). Cambridge Conservation Study 1985: Taita Hills, Kenya. International Council for Bird Preservation, Cambridge.
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APPENDIX 1: STRICT ENDEMIC VERTEBRATE SPECIES IN THE EASTERN ARC MOUNTAINS Habitat codes: FF = strict forest endemic; F = forest endemic which are ranges outside of forest on some occasions, but is probably dependent on forest for breeding; G/H = grassland or heathland species; W = montane wetland species. BIRDS Anthreptes rubritorques Sclater & Moreau, 1935, F, 250-1600m, Udzungwa, E. Usambara, Uluguru, Nguru Bathmocercus winifredae (Moreau, 1938), FF, 1500-1850m, Ukaguru, Uluguru, Udzungwa, Rubeho Bubo vosseleri Reichenow, 1907, F, 300-1000 m+, E. Usambara, Uluguru, Udzungwa, S. Pare (last three unpublished sound records) Hylotia usambarae E. Usambara Malaconotus alius Friedmann, 1927, FF, 1320-1710 m, Uluguru Nectarinia loveridgei (Hartert, 1922), FF, 1200-2580 m, Uluguru Nectarinia moreaui (Sclater, 1933), F, 1500-1850 m, Nguru, Ukaguru, Rubeho, Uvidunda Nectarinia rufipennis Jensen, 1983, FF, 600-1710 m, Udzungwa Ploceus nicolli Sclater, 1931, FF, Usambara, Uluguru, Udzungwa Sheppardia montana (Reichenow, 1907), FF, 1500-1850 m, W. Usambara Xenoperdix udzungwensis Dinesen et al., 1994, FF, 1350-1900 m, Udzungwa
Zosterops winifredae South Pare
MAMMALS Cercocebus ‘sangei’, FF, Udzungwa Crocidura tansaniana Hutterer, 1986, FF, Usambara Crocidura telfordi Hutterer, 1986, FF, Uluguru Crocidura usambarae Dippenaar, 1980, FF, West Usambara only Galagoides cf. orinus (Montane) P. Honess, 1996, FF, Usambara, Uluguru, Nguru, Udzungwa Myosorex geata (Allen & Loveridge, 1927), FF, Uluguru (if M. zinki is included then Kilimanjaro, Mt Meru, Southern Highland) Paraxerus vexillarius (Kershaw, 1923), FF, Usambara (if P. byatti is included then Kilimanjaro, Uluguru, Udzungwa and Southern Highland) Philocolobus ‘gordonorum’, FF, Udzungwa Sylvisorex howelli Jenkins, 1984, FF, Usambara and Uluguru REPTILES. Agama montana Barbour & Loveridge 1928, Usambara, Nguru, Uluguru Amblyodipsas teitana Broadley, 1971, Taita Hills Atheris ceratophorus Werner, 1895, Usambara, Uluguru, Udzungwa Bradypodion oxyrhinum Klaver & Böhme, 1988, Uluguru, Udzungwa Bradypodion spinosum Matschie, 1892, Usambara Chamaeleo deremensis Matschie, 1892, Usambara, Nguru Chamaeleo laterispinis Loveridge, 1953, Udzungwa Chamaeleo werneri Tornier, 1899, Uluguru, Udzungwa Dipsadoboa werneri Boulenger, 1897, Usambara (one record from Tanga; Broadley & Howell, in press) Elapsoidea nigra Günther, 1888, Usambara, Uluguru Geodipsas procterae Loveridge, 1922, Uluguru, Udzungwa Geodipsas vauerocegae Tornier, 1902, Usambara, Uluguru Leptosiaphos rhomboidalis Broadley, 1989, Udzungwa Lycophidion uzungwense Loveridge, 1932, Udzungwa Lygodactylus gravis Pasteur, 1964, Usambara Proscelotes eggeli Tornier, 1902, Usambara Prosymna ornatissima Barbour & Loveridge, 1928, Uluguru Rhampholeon uluguruensis Tilbury & Emmrich, 1996, Uluguru Rhampholeon sp. nov., Tilbury & Emmrich, in press, Nguru Scelotes uluguruensis Barbour & Loveridge, 1928, Uluguru, Nguru Typhlops gierrai Mocquard, 1897, Usambara, Uluguru, Nguru, Ukaguru Typhlops uluguruensis Barbour & Loveridge, 1928, Uluguru Urocotyledon wolterstorffi Tornier, 1900, Usambara, Uluguru AMPHIBIANS Afrixalus uluguruensis Barbour & Loveridge, 1928, FF, Usambara, Uluguru, Nguru, Udzungwa (possible same species from Mkwaja Coastal Forests, Poynton, in press) Arthroleptides martiensseni Nieden, 1910, FF, Usambara, Uluguru, Nguru, Udzungwa (300 m in E. Usambara; Poynton, in press)
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Arthroleptis tanneri Grandison, 1983, FF, Usambara Arthroleptis xenodactylus Boulenger, 1909, F, Usambara, Nguru, Uluguru? Bufo brauni Nieden, 1910, FF, Usambara, Uluguru, Udzungwa (at 300 m in E. Usambara) Callulina kreffti Nieden, 1910, FF, Usambara, Nguru, Uluguru, Udzungwa, Taita Hoplophryne rogersi Barbour & Loveridge, 1928, FF, Usambara Hoplophryne uluguruensis Loveridge, 1925, FF, Uluguru and Usambara Hyperolius tanneri Schiøtz, 1982, FF, Usambara Hyperolius tornieri Ahl, 1931, FF?, Uluguru Hyperolius sp. nov., Schiøtz & Westergaard, in press, FF, Udzungwa Leptopelis barbouri Ahl, 1929, FF, Usambara, Udzungwa (at 300 m in E. Usambara). Leptopelis parkeri Barbour & Loveridge, 1928, FF, Usambara, Uluguru, Udzungwa (at 300 m in the E. Usambara; Poynton, in press) Leptopelis uluguruensis Barbour & Loveridge, 1928, FF, Usambara, Uluguru, Nguru, Udzungwa (at 300 m in the E. Usambara) Nectophrynoides cryptus Perret, 1971, FF, Uluguru Nectophrynoides minutus Perret, 1972, FF, Uluguru Nectophrynoides tornieri Roux, 1906, FF, Usambara, Uluguru, Nguru, Udzungwa Nectophrynoides wendyae Clarke, 1988, 1989, FF, Udzungwa Nectophrynoides sp. nov. A, FF, Udzungwa Nectophrynoides sp. nov. B, FF, W. Usambara Parahoplophryne usambarica Barbour & Loveridge, 1928, FF?, Usambara Phrynobatrachus kreffti Boulenger, 1909, F, Usambara Phrynobatrachus uzungwensis Grandison & Howell, 1983, FF, Udzungwa, Uluguru Phlyctimantis keithae Schiøtz, 1974, F, G/H, Udzungwa Probreviceps uluguruensis Loveridge, 1925, FF, Uluguru Scolecomorphus uluguruensis Barbour & Loveridge, 1928, FF, Uluguru Scolecomorphus vittatus Boulenger, 1895, FF, Usambara, Uluguru, Pare? Boulengerula boulengeri Tornier, 1896, FF, Usambara, Nguru Boulengerula taitana Loveridge, 1935, ?, Taita Hills Boulengerula uluguruensis Barbour & Loveridge, 1928, FF, Uluguru
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APPENDIX 2: Large moist forest trees endemic to the Eastern Arc (with some lowland taxa also occurring in coastal forest) (from Lovett, 1998a). A large tree is defined as being > 20 cm diameter at breast height. No=northern Eastern Arc (Usambara, Taita, Pare); Ce=central Eastern Arc (Nguru, Uluguru, Ukaguru, Rubeho); So=southern Eastern Arc (Udzungwa, Mahenge); DL=dry lowland forest; LF=lowland forest; SM=submontane forest; MF= montane forest; DM = dry montane forest; UM = upper montane forest. Forest types follow Lovett (1993). Family and Species Anisophyllaceae Anisophyllea obtusifolia Engl. & Brehm. Annonaceae Annonaceae gen. nov. = Ede 65 Anonidium usambarense R.E. Fries Enantia kummeriae Engl. & Diels Greenwaydendron suaveolens (Engl. & Diels) Verdc. subsp. usambaricum Verdc. Isolona heinsenii Engl. & Diels Lettowianthus stellatus Diels Polyceratocarpus scheffleri Engl. & Diels Uvariodendron gorgonis Verdc. Uvariodendron oligocarpum Verdc. Uvariodendron pycnophyllum (Diels) R.E. Fries Uvariodendron usambarense R.E. Fries Araliaceae Polyscias stuhlmannii Harms Schefflera lukwangulensis (Tennant) Bernardi Celastraceae Platypterocarpus tanganyikensis Dunkley & Brenan Chrysobalanaceae Hirtella megacarpa R. Grah. Clusiaceae Allanblackia stuhlmannii (Engl.) Engl. Allanblackia ulugurensis Engl. Garcinia semseii Verdc. Mammea usambarensis Verdc. Ebenaceae Diospyros kabuyeana F. White Diospyros occulta F. White Diospyros sp. aff. amaniensis Guerke Euphorbiaceae Croton dictyophlebodes A.R.-Sm. Drypetes usambarica (Pax) Hutch. Macaranga conglomerata Brenan Sibangea pleioneura A.R.-Sm. Fabaceae Angylocalyx braunii Harms Cynometra brachyrrachis Harms Cynometra engleri Harms Cynometra longipedicellata Harms Cynometra sp. A Cynometra sp. B
No 1
Ce So DL LF SM MF DM 1
1
1 1 1 1 1 1
1
1
1
1
1 1 1
1 1 1 1
1 1
1
1 1 1 1 Also coastal 1
1
1
Also coastal 1
1 1
1
1
1
1
1
1
1
1 1
1
1
1
1
1
1
1 1 1
1 1 1
1 1 1
1 1 1
1
1 1 1
1 1 1
1
1
1 1
1
1
1
1
Also coastal Also coastal
1
1
1 1 1 1 1 1 1
1 1
1
1 1 1
Coastal
1
1 1 1
UM
1
1
1
1 1 1
1 Also coastal
1 1
1 1 1
Also coastal
1 1 1
14
No Cynometra ulugurensis Harms Englerodendron usambarense Harms Isoberlinia scheffleri (Harms) Greenway Millettia elongatistyla Gillett Newtonia paucijuga (Harms) Brenan Pterocarpus mildbraedii Harms subsp. usambarensis (Verdc.) Polhill Scorodophloeos fischeri (Taub.) J. Léon. Zenkerella capparidacea (Taub.) J. Léon. Zenkerella egregia J. Léon. Zenkerella perplexa Temu Flacourtiaceae Casearia engleri Gilg Lauraceae Beilschmidia kweo (Mildbr.) Robyns & Wilczek Melastomataceae Lijndenia brenanii (A. & R. Fernandes) Jacq. Fél. Lijndenia greenwayii (Brenan) Borhidi Memecylon sp. A Memecylon teitense Wickens Myristicaceae Cephalosphaera usambarensis (Warb.) Warb. Myrtaceae Syzygium sclerophyllum Brenan Ochnaceae Ouratea scheffleri Engl. & Gilg Ouratea schusteri Gilg ex Engl. Octoknemataceae Octoknema orientalis Mildbr. Pittosporaceae Pittosporum goetzei Engl. Rutaceae Calodendrum eickii Engl. Sapindaceae Allophylus melliodorus Radlk. Placodiscus amaniensis Radlk. Placodiscus pedicellatus F.G. Davies Sapotaceae Neohemsleya usambarensis Pennington Omphalocarpum strombocarpum Y.B. Harv. & J.C. Lovett Pouteria pseudoracemosa (J.H. Hemsl.) L. Gautier Simaroubaceae Odyendea zimmermannii Engl. Sterculiaceae Cola scheffleri K. Schum. Tiliaceae Grewia goetzeana K. Schum. Verbenaceae Vitex amaniensis Pieper Totals
1 1 1 1 1 1 1 1
Ce So DL LF SM MF DM 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1
1 1
1
1
1
1
1
1
1
1 1
1
1
1 1 1
1 1
1 1
1
1
1
1
1
1
1
1 1
1
1
1
1
1
1 1 1
1
1
1 1 1
1 1
1
1 1 1
1 1
1
1 1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1 53
Coastal
Also coastal 1
1
1
UM
1 1 37 36
5
1 19 37
Also coastal
1 22
3
5
15
Figure 1. Division of Tanzanian forests on the basis of geology and climate (from Lovett, 1990; 1998a). Forest distribution is based on forest reserves containing closed forest formations. Coastal, Eastern Arc and Northern forests are under the direct climatic influence of the Indian Ocean, but Coastal forests are predominantly on sedimentary rocks, the Eastern Arc are on igneous and metamorphic rocks, and Northern forests are predominantly on volcanic areas (with the exception of the Mbulu highlands). Forests associated with the great lakes of Victoria, Tanganyika and Nyasa are subject to environmental fluctuations associated with variation in the local climates associated with these lakes.
16
Numbers of Species/area x 100
35 30 25 20 15 10 5
Single Block Endemics
Udzungwa
Mahenge
Malundwe Hill
Uluguru
Rubeho
Ukaguru
Nguru
Nguu
East Usambaras
West Usambara
South Pare
North Pare
Taita Hills
0
Eastern Arc Mountains Eastern Arc Endemics
Eastern Arc Near-endemics
Figure 2. Numbers of endemic vertebrate species in relation to the remaining forest area.
17
Area of forest (sq km)
600 500 400 300 200 100 0 Historical
1955
1977
2000
Reserves
Dates
Figure 3. Changes in the area of forest on the Uluguru Mountains. ‘Historical’ is estimated from climate and the extent of lowland forest patches which are assumed to have been originally joined. Estimates for 1955 and 1977 are based on aerial photographs, and for 2000 on ground surveys. ‘Reserves’ is an estimate of the minimum forest area if the present reserves are maintained, with little encroachment, but all forest outside is lost (around 20 sq km of the Uluguru Forest reserves is upland grassland and some is rock).
18
Forest in altitude bands (ha)
3500 3000
PA 1955 PA 1977
2500 2000 1500 1000 500
25 00
23 00
21 00
19 00
17 00
15 00
13 00
11 00
90 0
70 0
50 0
0
200 m altitudinal bands
Figure 4. Altitudinal distribution of montane forests in the Uluguru Mountains, 1955 and 1977, illustrating the greatest forest loss between 700 and 1700 m, and very little forest loss above this altitude.
19
Number of endemic species
80 70 60 50 40 30 20 10 0 Lowland
Sub-montane
Montane
Upper Montane
Forest altitude bands
Figure 5: Altitudinal Distribution of Uluguru Mountains Strict Endemic Plants (grey) and Strict endemic Animals (black). Most of these strict endemics are forest species. Lowland forest ranges from 0-800m, sub-montane forest from 900-1500 m, montane forest from 1500-2100 m and upper montane forest above 2100 m.
20
