Elevational Distribution Ofrestricted Range Forest

540 Biodiversity and CiJ1fJervarton 10: 541-550.2001. Q 2001 Xluwer Academic Publishers. Printed in the NetherlandJ. Taylor JS, Church KE and Rusch DH (1999) Microhabitat selection by nesting and brood-rearing northern bobwhite in Kansas. Journal of Wildlife Management 63: 686-694 Terborgh 1. Estes lA. Paquet P. Ralls K, Boyd-Heger D. Miller 81 and Noss RF (1999) The role of lOp car. nivores in regulating lerreslrial ecosystems. In: Soule ME and Terborgh (OOs) Continenlal Conservation, Elevational distribution of restricted range forest tree PP 39-64. Island Press, Washington. DC Torger.;en TR and Bull EL (1993) Toe atrophy caused by carpenter ants in Vaux's swiflS. AvocetL'\ 17: taxa in eastern Tanzania •• 209-210 • Torgmen TR and Bull EL (1995) Down logs as habitat for forest-dwelling ants -the primary prey of pileated woodpeckers in northeastern Oregon. Northwest Science 69: 294-303 JON C, LOVETIJ", G. PHILIP CLARKEJ,2, ROBIN MOOREJ Tremblay JP. Gauthier G, Lepage 0 and Desrochers A (1997) Factors affecting nesting success in greater snow geese: effects of habitat and association with snowy owls. Wilson Bullettn 109: 449-461 and GILBERT H, MORREy3 Uchida H (1986) Passerine birds nesting close to the nests of birds of prey. Japanese Journal of Ornithology J Environmenl Department, Universiry of York, York YOlO 5DD, UK; 1PnsenJ address: The Hennirage, 35; 25-32 [in Japanese with English summary] Crewkeme, Somuut TAl8 8ET, UK; 336 CONUlughrRoad, Nunthorpe, MiddJesborough TS708S, UK; Uela M (1994) Azure-winged magpies. Cyanopica C)'Q1Ul. 'parasitise' nest defense provided by Japanese •Author for correspondence (e- mail: [email protected];fax: +44-/904.431998) lesser sparrowhawks. Accipirer guJaris. Animal Behaviour 48: 871-874 Ueta M (1998) Azure-winged magpies avoid nest predation by nesting near a Japanese lesser spalTow- Received 7 July 1997; accepted in revised form 4 May 2000 hawk's nest. Condor 100: 400-402 Vlilinlinen VM (2000) Predation risk associate1 with nesting in gull colonies by two Ayrhya species: observalions and an experimental test. Jouma.! of Avian Biology 31: 31-35 Vermeer K (I %8) Ecological aspects of ducks nesting in high densities among lands. Wilson Bulletin 80: Abstract. The forests of eastern Tanzania are a globally important biodiven>ity hotspot. In this study 361 7B-B3 eastern Tanzanian restricted range forest tree taxa were assessed. Of these taxa, 223 occurred in the Eastern Vermeer K (1970) Breeding biology of California and ring.billed gulls: a study of ecological adaptation to Are, 150 in Coastal forests. 17 in Northern forests and 21 in the Lake Nyasa forests. The majority of the the inland habitat. Canadian Wildlife Service Report Series 12 taxa had restricted e1evational ranges with 76.3% occurring in no more than two 200 m e1evalional bands Werner HE (1992) Individual behavior and higher-order species interactions. American Naturalist 140: out of a total potential elevation range of 3000 m. The majority of the taxa occupied a small area in the SS-S32 eastern T~nzanian f~rests, with 201 taxa being only found at a few sites. In determining priority areas for Werner EE and Anholt BR (1996) Predator-induced behavioral indirect effects: consequences to competi. conservation. selection of taxon definitions can have imponant effects. For example. tree size varies with tive inleractions in anurnn larvae. Ecology 77: 157-169 elevation, so if only large trees are used then site selection will be biased towards particular areas, Wheelwright NT, Lawler JJ and Weinstein JH (1997) Nest.site selection in Savannah sparrows: using gulls as scarecrows? Animal Behaviour 53: 197-208 Key words: elevation range, forests, rarity, Tanzania, trees Whittaker 18 (l991) Effects of ants on temperate woodland trees. In: Huxley CR and CUller OF (eds) , Ant-ph:m! Interactions. PP 67-79. O:tford Univeristy Press. Oxford . Wiklund CG (1982) Fieldfare (Turdus pi/oris) breeding success in relation to colony size. nest position and Introduction , association with merlins (Fulco columburius). Behavioml Ecology and Sociobiology II: 165-172 Wilcove OS (1985) Nest predation in forest tracts and the decline of migralOry songbirds. Ecology 66: 1211-1214 Working on the assumption that resources for conservation are scarce, large scale Witmer GW. Bucknall JL, Fritts TH and Moreno DG (1996) Predator management to protect endangered compilation, of distribution patterns have, been used to highlight global priori,¥, ar- avian species. Transactions of the Nonh American Wildlife and Natural Resources Conference 61: 102- JOB eas on the basiS of thetr bIOlogical diverSity (e.g. Mittenneier et al. 2000. Williams WOOllon JT (l993) Indirect effects and habitat use in an intertidal community: interaction chains and and Gastnn 1994; Williams et a!. 1996), Whilst global conservation priOri:ies can 6e inleracLion modifications. American Naturalist 141: 71-89 identified by the use of such spatially relatively coarse data, conservation is ultimately Wunderle JM and Pollock KH (198:5) The bananaquit-wasp nesting association and a random choice model. Ornithological Monographs 36: :595-603 effected by)ocal implementation. which requires a fine grained analysis pinpointing Young BE, Kaspan M and Manin TE (1990) Species-specific nest site selection by birds in anHlcacia key areas or habitat types_ trees. BiotrOpica 22: 31o-3l5 The forests on the mountains and coastal plains of eastern Tanzania are recognised as one of the world's mnst important biodiversity hotspnts (Myer! 1990; Myers et al, 2000), The forests contain a remarkable number of pl,ant species of restricted geographical distribution (Burgess et a!. 1998; Lovetl 1988; Lovett et a!. 2000; Polhill 1968) that appear to be both recently evolved neo-endemics and ancient relictudh •••• palaeo~endemics (Lovett and Friis 1996). Such geographically rare species may also be locally rare, for example they may have a limited elevational range and low abun- dance (Gaston 1994), a fact that will affect management for conservation within the biodiversity hotspot. , 542 543 Once global conservation priorities have been determined, knowledge of the local ecology and distribution of geographical rare species are needed 10 formulate effec- tive management plans., For example, the Tanzanian forests occur in an area where there are sharp topographic. climatic and edaphic gradients that may affect local species distributions. They are highly fragmented, with many small patches covering • Fo •• " •••• ..". only a few hectares that can be rich in restricted range plant taxa, Moreover, the Tanzanian forests are still poorly known biologically with many new species still being discovered. Consequently, knowledge of general ecological patterns of restricted range taxa may help to formulate management plans that are relevant to as yet undis- covered species. In this study we compile information on as many restricted range trec taxa as possible. dividing them into categories based 00 taxonomic rank, geographical distribution, elevational dislributioo and habit. The aim is to ascertain if taxa defined as rare in the sense of having restricted geographical ranges at a continental scale, also have reslricted local geographical and elevational distributions. The results are discussed in the context of specific management strategies. Methods The list of restricted range forest taxa in eastern Tanzania was initially compiled from information contained in the Flora of Tropical East Africa (FTEA) (Turrill et al. o tOO 200 1952-), for taxa defined as a 'tree' in growth habit. This covered plants from a few Idlomeltat; metres to over 60 m tall. Our own field observations were used to supplement this information. The eastern Tanzanian list was originally complied for the World List of Threatened Trees (Oldfield et al. 1998). The list was hroken down by a number f'gure J. Location of the Northern, Eastern Arc. Lake Nyasa and Coastal forests in Tanzania (after Lovett of variables for analysis: height, taxonomic rank, habit, distribution and habitat. 1990). Eastern Tanzanian forests were defined as closed canopy evergreen or semi-evergreen vegetation formations east of the arid corridor (sensu Wergcr 1978) and divided into but whi~h we considered t~ be forest plants were also included. Taxa were dividect.fto Eastern Arc forests, Coastal forests, Northern forests and Lake Nyasa forests (sensu three height classes aceordmg to the tallest record of the tree cited in the FfEA or from Lovett 1990; Figure I). The Eastern Arc forests accuron a range of ancient crystalline our own field observations: <10 m tall, 10-20 m tall and >20 m tall. Four levels o'f mountains that run from the Taita hills, Kenya to the Makambako Gap in the southern taxonomic rank were considered: genus, species, subspecies and variety. 1\\'0 growth Udzungwa mountains, Tanzania. The Coastal forests (in Tanzania) are predominatelyon habits were recognised: 'shrubby trees' (i.e. trees which have also been recorded as the sedimentary rocks and derived formations between the Eastern Arc and the Indian shrubs) and trees that have only been recorded as trees. Four patterns of restricted Ocean coastline. The Northern forests are on the northern Tanzanian volcanics and "range distribution were used: restricted to a few specific localities in Tanzania (F); associated mountains on the rift valley. The Lake Nyasa forests are in the high rainfall occurring in several to many localities in Tanzania (T); Oecumng i~Tanzania and any area of northern Lake Nyasa south of the Makambako Gap and are predominately one of the neighbouring countries (T + 1); and a widely 4isjunct population of a taxon on Pliocene volcanics or volcanic soils overlying crystalline basement rocks. The occurring elsewhere (D). The elevational range of each taxon in 200 m elevation bands maximum elevation of each forest type is: Eastern Arc forests 2400 m. Coastal forests over a total elevational range of 0 to 3000 m (IS bands) was also recorded. ., ••• 1100 m (but usually much lower), Northern forests 3000 m, and Lake Nyasa forests P:~blems encountered included the desc"ription of a number of FfEA collecting 2850 m.

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