Biodiversity and Conservation

, Volume 27, Issue 6, pp 1387–1402 | Cite as

Impact of habitat fragmentation on the spatial structure of the Eastern Arc forests in East Africa: implications for biodiversity conservation

Original Paper
  • 265 Downloads
Part of the following topical collections:
  1. Forest and plantation biodiversity

Abstract

The Eastern Arc Mountains in Tanzania and Kenya are one of 35 global biodiversity hotspots. The Eastern Arc forests are, as are many other tropical biodiversity hotspots, highly fragmented. Understanding the impact of habitat fragmentation (i.e., habitat loss and subdivision) on the spatial structure of the Eastern Arc forests is important because forest spatial structure highly influences species richness, persistence, and extinction debt. Here we examine the impact of habitat fragmentation on the spatial structure of the Eastern Arc forests at a patch scale using very high resolution aerial imagery having a spatial resolution of 0.5–1.5 m. Forest area across the 13 Eastern Arc Mountains is 405,852 ha and is distributed into 311 fragments ≥ 10 ha in size with a median fragment size of 84 ha. The 18 largest forest fragments in the Eastern Arc Mountains contain greater than three-quarters of total forest area. Average fragment isolation, as assessed by median distance to nearest fragment and median distance to the nearest larger fragment, is 867 and 1533 m, respectively. Of total forest area, 14% is < 100 m from the forest edge and 33% is < 300 m from the forest edge. Establishing forested linkages among the largest and closest forest fragments through forest regeneration and protection of secondary regenerating forest as well as providing protected area status to the remaining non-protected forest including unprotected smaller forest fragments are important to enhancing the long-term persistence of many plant and animal species here.

Keywords

Fragment size and number Fragment isolation Edge area Forest cover Kenya Tanzania 

Notes

Acknowledgements

We thank the Danish International Development Agency, Field Museum of Natural History, Chicago Zoological Society, Sophie Danforth Conservation Fund, National Geographic Society (#524-94, #977815), Earthwatch Institute, John D. and Catherine T. MacArthur Foundation, Critical Ecosystem Partnership Fund, World Wide Fund for Nature, and Earth Point Corporation for support, and the Tanzania Wildlife Research Institute and Tanzania Commission for Science and Technology for permission to conduct this study.

References

  1. Aben J, Adriaensen F, Thijs KW, Pellikka P, Siljander M, Lens L, Matthysen E (2012) Effects of matrix composition and configuration on forest bird movements in a fragmented Afromontane biodiversity hotspot. Anim Conserv 15(6):658–668CrossRefGoogle Scholar
  2. Benker SC, Langfor RP, Pavlis TL (2011) Positional accuracy of the Google Earth terrain model derived from stratigraphic unconformities in the Big Bend region, Texas, USA. Geocarta Int 26:291–303CrossRefGoogle Scholar
  3. Borghesio L, John JRM, Mulungu E, Mkongewa V, Joho M, Cordeiro NJ (2008) Observation of threatened birds in the East Usambara Mountains, Tanzania. Bull Afr Bird Club 15:59–70Google Scholar
  4. Brooks TM, Pimm SL, Oyugi JO (1999) Time lag between deforestation and bird extinction in tropical forest fragments. Conserv Biol 13:1140–1150CrossRefGoogle Scholar
  5. Brown JH, Kodric-Brown A (1977) Turnover rates in insular biogeography: effect of immigration on extinction. Ecology 58:445–449CrossRefGoogle Scholar
  6. Burgess ND, Butynski TM, Cordeiro NJ, Doggart NH, Fjeldså J, Howell KM, Kilahama FB, Loader SP, Lovett JC, Mbilinyi B, Menegon M, Moyer DC, Nashanda E, Perkin A, Rovero F, Stanley WT, Stuart SN (2007) The biological importance of the Eastern Arc Mountains of Tanzania and Kenya. Biol Conserv 134:209–231CrossRefGoogle Scholar
  7. Conte C (2004) Highland sanctuary: environmental history in Tanzanian’s Usambara Mountains. Ohio University Press, AthensGoogle Scholar
  8. Cordeiro NJ, Howe HF (2001) Low recruitment of trees dispersed by animals in African forest fragments. Conserv Biol 15:1733–1741CrossRefGoogle Scholar
  9. Cordeiro NJ, Howe HF (2003) Forest fragmentation severs mutualism between seed dispersers and an endemic African tree. Proc Natl Acad Sci USA 24:14052–14056CrossRefGoogle Scholar
  10. Cordeiro NJ, Ndangalasi HJ, McEntee JP, Howe HF (2009) Disperser limitation and recruitment of an endemic African tree in a fragmented landscape. Ecology 90:1030–1041CrossRefPubMedGoogle Scholar
  11. Cordeiro NJ, Borghesio L, Joho MP, Monoski TJ, Mkongewa VJ, Dampf CJ (2015) Forest fragmentation in an African biodiversity hotspot impacts mixed-species bird flocks. Biol Conserv 188:61–71CrossRefGoogle Scholar
  12. Dale VD, Pearson SM, Offerman HL, O’Neill RV (1994) Relating patterns of land-use change to faunal biodiversity in the Central Amazon. Conserv Biol 8(4):1027–1036CrossRefGoogle Scholar
  13. Davenport TRB, Stanley WT, Sargis EJ, De Luca DW, Mpunga NE, Machaga SJ, Olson LE (2006) A new genus of African monkey Rungwecebus: morphology, ecology, and molecular phylogenetics. Science 312:1378–1381CrossRefPubMedGoogle Scholar
  14. Davis AP, Mvungi EF (2004) Two new and endangered species of Coffea (Rubiacea) from the Eastern Arc Mountains (Tanzania) and notes on associated conservation issues. Bot J Linn Soc 146:237–245CrossRefGoogle Scholar
  15. Develey PF, Stouffer PC (2001) Effects of roads on movements by understory birds in mixed-species flocks in central Amazonian Brazil. Conserv Biol 15:1416–1422CrossRefGoogle Scholar
  16. Diamond JW (1971) Comparison of faunal equilibrium turnover rates on a tropical island and a temperate island. Proc Natl Acad Sci USA 68:2742–2745CrossRefPubMedPubMedCentralGoogle Scholar
  17. Diamond JW (1972) Biogeographic kinetics: estimation of relaxation times for avifaunas of southwestern Pacific islands. Proc Natl Acad Sci USA 69:3199–3203CrossRefPubMedPubMedCentralGoogle Scholar
  18. Didham RK, Hammond PM, Lawton JH, Eggleton P, Stork NF (1998) Beetle species responses to tropical forest fragmentation. Ecol Monogr 68:295–323CrossRefGoogle Scholar
  19. Dinesen L, Lehmberg T, Svendsen JO, Hansen LA, Fjeldså J (2004) A new genus and species perdicine bird (Phasianidae, Perdicini) from Tanzania) a relict form with Indo-Malayan affinities. Ibis 136:2–11Google Scholar
  20. Earth Point (2015) Earth Point Corp, Kuna, ID. Available: https://www.earthpoint.us
  21. ESRI (2016) ARCGIS Desktop. Release 10.4.1 Environmental Systems Research Institute, RedlandGoogle Scholar
  22. Fahrig L (2003) Effects of habitat fragmentation on biodiversity. Annu Rev Ecol Evol Syst 34:487–515CrossRefGoogle Scholar
  23. Fisher D, Turner RK, Burgess ND, Swetman RD, Green J, Green RE, Kajembe G, Kulindwa K, Lewis SL, Marchant R, Marshall AR, Madoffe S, Munishi PKT, Morse-Jones S, Mwakalila S, Paavola J, Naidoo R, Ricketts T, Rouget M, Willcock S, White S, Balmford A (2011) Measuring, modeling and mapping ecosystem services in the Eastern Arc Mountains of Tanzania. Prog Phys Geog 35:595–611CrossRefGoogle Scholar
  24. Haddad NM, Brudvig LA, Clobert J, Davies KF, Gonzalez A, Holt RD, Lovejoy TE, Sexton JO, Austin MP, Collins CD, Cook WM, Damschen EI, Ewers RM, Foster BL, Jenkins CN, King AJ, Laurance WF, Levey DJ, Margules CR, Melbourne BA, Nicholls AO, Orrock JL, Song D-X, Townshend JR (2015) Habitat fragmentation and its lasting impact on Earth’s ecosystems. Sci Adv.  https://doi.org/10.1126/sciadv.1500052 PubMedPubMedCentralGoogle Scholar
  25. Hall J, Burgess ND, Lovett J, Mbilinyi B, Gereau RE (2009) Conservation implications of deforestation across and elevational gradient in the Eastern Arc Mountains, Tanzania. Biol Conserv 142:2510–2521CrossRefGoogle Scholar
  26. Halley JM, Iwasa Y (2011) Neutral theory as a predictor of avifaunal extinctions after habitat loss. Proc Natl Acad Sci USA 108:2316–2321CrossRefPubMedPubMedCentralGoogle Scholar
  27. Halley JM, Monokrousos N, Mazaris AD, Newmark WD, Vokou D (2016) Dynamics of extinction debt across five taxonomic groups. Nat Commun 7:12283CrossRefPubMedPubMedCentralGoogle Scholar
  28. Hansen MC, Potapov PV, Moore R, Hancher M, Turubanova SA, Tyukavina A, Thau D, Stehman SV, Goetz SJ, Loveland TR, Kommareddy A, Egorov A, Chini L, Justice CO, Townshend JRG (2013) High-resolution global maps of 21st-century forest cover change. Science 342:850–853CrossRefPubMedGoogle Scholar
  29. Hanski I, Zurita GA, Bellocq I, Rybicki J (2013) Species-fragmented area relationship. Proc Natl Acad Sci USA 110:12715–12720CrossRefPubMedPubMedCentralGoogle Scholar
  30. Heckmann M, Muiruri V, Boom B, Marchant R (2014) Human-environment interactions in an agricultural landscape: a 1400-yr sediment and pollen record from North Pare, NE Tanzania. Paleogeogr Paleoclimatol Paleoecol 46:49–61CrossRefGoogle Scholar
  31. Iversen ST (1991) The Usambara mountains, NE Tanzania: phytogeography of the vascular plant flora. Acta Univ Ups Symb Bot Ups 23:3Google Scholar
  32. John JRM, Kabigumila JDL (2007) Impact of Eucalyptus plantations on the avian breeding community in the East Usambaras, Tanzania. Ostrich 78:265–269CrossRefGoogle Scholar
  33. Klein BC (1989) Effects of forest fragmentation on dung and carrion beetle communities in central Amazonia. Ecology 70:1715–1725CrossRefGoogle Scholar
  34. Korfanta N, Newmark WD, Kauffman MJ (2012) Long-term demographic consequences of habitat fragmentation to a tropical understory bird community. Ecology 93:2548–2559CrossRefPubMedGoogle Scholar
  35. Kuussaari M, Bommarco R, Heikkinen RK, Helm A, Krauss J, Lindbord R, Öckinger E, Pärtel M, Pino J, Rodá F, Stefanescu C, Teder T, Zobel M, Steffan-Dewenter I (2009) Extinction debt: a challenge for biodiversity conservation. Trends Ecol Evol 24:564–571CrossRefPubMedGoogle Scholar
  36. Laurance WF (2008) Theory meets reality: how habitat fragmentation research has transcended island biogeographic theory. Biol Conserv 141:1731–1744CrossRefGoogle Scholar
  37. Laurance SGW, Gomez MS (2005) Clearing width and movements of understory rainforest birds. Biotropica 37:149–152CrossRefGoogle Scholar
  38. Laurance WF, Lovejoy TE, Vasconcelos HL, Bruna EM, Didham RK, Stouffer PC, Gascon C, Bierregaard RO, Laurance SG, Sampaio E (2002) Ecosystem decay of Amazonian forest fragments: a 22-year investigation. Conserv Biol 16:605–618CrossRefGoogle Scholar
  39. Lees AC, Peres CA (2008) Gap-crossing movements predict species occupancy in Amazonian forest fragments. Oikos 118:280–290CrossRefGoogle Scholar
  40. Lens L, Van Dongen S, Norris K, Githiru M, Matthysen E (2002) Avian persistence in fragmented rainforest. Science 298:1236–1238CrossRefPubMedGoogle Scholar
  41. Lovett JC (1993) Eastern Arc moist forest flora. In: Lovett JC, Wasser SK (eds) Biogeography and ecology of the rain forests of eastern Africa. Cambridge University Press, Cambridge, pp 33–55CrossRefGoogle Scholar
  42. Lovett JC, Wasser SK (eds) (1993) Biogeography and ecology of the rain forests of eastern Africa. Cambridge University Press, CambridgeGoogle Scholar
  43. Mbilinyi BP, Malimbwi RE, Shemwetta DTK, Songorwa E, Sahabu E, Katani JZ, Kashaigili J (2006) Forest area baseline for the Eastern Arc Mountains. Forestry and Beekeeping Division, Dar es SalaamGoogle Scholar
  44. Menegon M, Salvido S, Loader SP (2004) Five new species of Nectophrynoides Noble 1926 (Amphibia Anura Bufonidae) from the Eastern Arc Mountains, Tanzania. Trop Zool 17:97–121CrossRefGoogle Scholar
  45. Mittermeier RA, Turner WR, Larsen FW, Brooks TM, Gascon C (2011) Global biodiversity conservation: the critical role of hotspots. In: Zachos FE, Habel JC (eds) Biodiversity hotspots: distribution and protection of priority conservation areas. Springer, Berlin, pp 3–22CrossRefGoogle Scholar
  46. Moilanen A, Nieminen M (2002) Simple connectivity measures in spatial ecology. Ecology 83:1131–1145CrossRefGoogle Scholar
  47. Montgomery FF, Sunquist ME (1978) Habitat selection and use by two toed and three toed sloths. In: Montgomery GG (ed) The ecology of arboreal folivores. Smithsonian Institution Press, Washington DC, pp 329–359Google Scholar
  48. Moore RP, Robinson WD, Lovette IJ, Robinson TR (2008) Experimental evidence for extreme dispersal limitation in tropical forest birds. Ecol Lett 11:960–968CrossRefPubMedGoogle Scholar
  49. Mumbi DT, Marchant R, Hooghiemstra H, Wooller MJ (2008) Late Quaternary vegetation reconstruction from the Eastern Arc Mountains, Tanzania. Quat Res 69:326–341CrossRefGoogle Scholar
  50. Mumbi DT, Marchant R, Lane P (2014) Vegetation response to climate change and human impacts in the Usambara Mountains. ISRN Forestry.  https://doi.org/10.1155/2014/240510 Google Scholar
  51. Murcia C (1995) Edge effects in fragmented forests: implications for conservation. Trends Ecol Evol 10:58–62CrossRefPubMedGoogle Scholar
  52. Myers N, Mittermeier RA, Mittermeier CG, da Fonseca AB, Kent J (2000) Biodiversity hotspots for conservation priorities. Nature 403:853–858CrossRefPubMedGoogle Scholar
  53. Newmark WD (1991) Tropical forest fragmentation and the local extinction of understory birds in the Eastern Usambara Mountains, Tanzania. Conserv Biol 5:67–78CrossRefGoogle Scholar
  54. Newmark WD (1993) The role and design of wildlife corridors with examples from Tanzania. Ambio 12:500–504Google Scholar
  55. Newmark WD (1998) Forest area, fragmentation, and loss in the Eastern Arc Mountains: implications for the conservation of biological diversity. J East Afr Nat Hist 87:29–36CrossRefGoogle Scholar
  56. Newmark WD (2001) Tanzanian forest edge microclimatic gradients: dynamic patterns. Biotropica 33:2–11CrossRefGoogle Scholar
  57. Newmark WD (2002) Conserving biodiversity in East African forests: A study of the Eastern Arc Mountains. Ecological Studies No. 155. Springer, New YorkCrossRefGoogle Scholar
  58. Newmark WD (2005) Diel variation in the difference in air temperature between the forest edge and interior in Tanzania. Afr J Ecol 43:177–180CrossRefGoogle Scholar
  59. Newmark WD (2006) A 16-year study of forest disturbance and understory bird community structure and composition in Tanzania. Conserv Biol 20:122–134CrossRefPubMedGoogle Scholar
  60. Newmark WD, Stanley TR (2011) Habitat fragmentation reduces nest survival in an Afrotropical bird community in a biodiversity hotspot. Proc Natl Acad Sci USA 108:11488–11493CrossRefPubMedPubMedCentralGoogle Scholar
  61. Newmark WD, Stanley TR (2016) The influence of food abundance, food dispersion, and habitat structure on territory selection and size of an Afrotropical insectivore. Ostrich 87:199–207CrossRefGoogle Scholar
  62. Newmark WD, McNeally PB (2018) Data from: Shapes files of forest fragments in the Eastern Arc Mountains. Dryad Digital Repository.  https://doi.org/10.5061/dryad.vk8cd Google Scholar
  63. Newmark WD, Mkongewa VJ, Sobek AD (2010) Ranging behavior and habitat selection of terrestrial insectivorous birds in northeast Tanzania: implications for corridor design in the Eastern Arc Mountains. Anim Conserv 13:474–482CrossRefGoogle Scholar
  64. Newmark WD, Stanley WT, Goodman SM (2014) Ecological correlates of vulnerability to fragmentation among Afrotropical terrestrial small mammals in northeast Tanzania. J Mammal 95:269–275CrossRefGoogle Scholar
  65. Newmark WD, Jenkins CN, Pimm SL, McNeally PB, Halley JM (2017) Targeted habitat restoration can reduce extinction rates in fragmented forests. Proc Natl Acad Sci USA 114:9635–9640CrossRefPubMedPubMedCentralGoogle Scholar
  66. Pimm SL, Raven P (2000) Extinction by numbers. Nature 403:843–845CrossRefPubMedGoogle Scholar
  67. Pimm SL, Brooks T (2014) Conservation: forest fragments, facts, and fallacies. Curr Biol 23:R1098–R1102CrossRefGoogle Scholar
  68. Platts PJ, Burgess ND, Gereau RE, Lovett JC, Marshall AR, McClean CJ, Pellikka PKE, Swetnam RD, Marchant R (2011) Delimiting tropical mountain ecoregions for conservation. Environ Conserv 38:312–324CrossRefGoogle Scholar
  69. Pócs T (1976) Bioclimatic studies in the Uluguru Mountains (Tanzania, East Africa). Acta Bot Acad Hung Tomus 22:163–183Google Scholar
  70. Potere D (2008) Horizontal positional accuracy of Google Earth’s high resolution imagery archive. Sensors 8:7973–7981CrossRefPubMedPubMedCentralGoogle Scholar
  71. Powell AH, Powell GVN (1987) Population dynamics of male euglossine bees in Amazonian forest fragments. Biotropica 19:176–179CrossRefGoogle Scholar
  72. Ribeiro MC, Metzger JP, Martensen AC, Ponzoni FJ, Hirota MM (2009) The Brazilian Atlantic forest: how much is left, and how is the remaining forest distributed? Implications for conservation. Biol Conserv 142:1141–1153CrossRefGoogle Scholar
  73. Rovero F, Rathbun GB, Perkin A, Jones T, Ribble DO, Leonard C, Mwakisoma RR, Doggart N (2008) A new species of giant sengi or elephant-shrew (genus Rhynchocyon) highlights the exceptional biodiversity of the Udzungwa Mountains of Tanzania. J Zool 274:126–133CrossRefGoogle Scholar
  74. Schmidt PR (1989) Early exploitation and settlement in the Usambara Mountains. In: Hamilton AC, Bensted-Smith R (eds) Forest conservation in the East Usambara Mountains, Tanzania. IUCN, Gland, pp 75–78Google Scholar
  75. Schwarzkopf L, Rylands AB (1989) Primate species richness in relation to habitat structure in Amazonian rainforest fragments. Biol Conserv 48:1–12CrossRefGoogle Scholar
  76. Sexton JO, Song X-P, Feng M, Noojipady P, Anand A, Huang C, Kim D-H, Collins KM, Channan S, DiMiceli C, Townshend JRG (2013) Global, 30-m resolution fields of tree cover: Landsat-based rescaling of MODIS vegetation continuous fields with lidar-based estimates of error. Int J Digit Earth 6:427–448CrossRefGoogle Scholar
  77. Shirk PL, Linden DW, Patrick DA, Howell KM, Harper EB, Vonesh JR (2014) Impact of habitat alternation on endemic Afromontane chameleons: evidence for historical population declines using hierarchical spatial modelling. Divers Distrib 20:1186–1199CrossRefGoogle Scholar
  78. Soper R (1967) Iron Age sites in north-eastern Tanzania. Azania 2:19–36CrossRefGoogle Scholar
  79. Spanhoven T, Lehouck V, Boets P, Lens L (2009) Forest fragmentation relaxes natural nest predation in an Afromontane forest. Anim Conserv 12:267–275CrossRefGoogle Scholar
  80. Stanley WT, Olson LE (2005) Phylogeny, phylogeography, and geographic variation of Sylvisorex howelli (Family Soricidae), an endemic shrew of the Eastern Arc Mountains, Tanzania. J Zool 266:341–354CrossRefGoogle Scholar
  81. Stanley WT, Hutterer R, Giarla TC, Esselstyn JA (2015) Phylogeny, phylogeography and geographical variation in the Crocidura monax (Soricidae) species complex from the montane islands of Tanzania, with descriptions of three new species. Zool J Linn Soc 174:185–215CrossRefGoogle Scholar
  82. Turner IM (1993) Species loss in fragments of tropical rain forest: a review of the evidence. J Appl Ecol 33:200–209CrossRefGoogle Scholar
  83. Uezu A, Metzger JP (2016) Time-lag responses of birds to Atlantic Forest fragmentation: restoration opportunity and urgency. PLoS One 11(1):e0147909.  https://doi.org/10.1371/journal.pone.0147909 CrossRefPubMedPubMedCentralGoogle Scholar
  84. Willis EO (1979) The composition of avian communities in luminescent woodlots in southern Brazil. Papé Avulsos Zool Sal Paulo 33:1–25Google Scholar
  85. Young R, Fosbrooke H (1960) Smoke in the hills: land and politics among the Luguru of Tanganyika. Routledge and Kegan Paul Ltd, LondonGoogle Scholar
  86. Zurita G, Pe’er G, Bellocq MI, Hansbauer MM (2012) Edge effects and their influence on habitat suitability calculations: a continuous approach applied to birds of the Atlantic forest. J Appl Ecol 49:503–512CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.Natural History Museum of UtahUniversity of UtahSalt Lake CityUSA
  2. 2.Department of GeographyUniversity of UtahSalt Lake CityUSA

Personalised recommendations