, Volume 43, Issue 2, pp 149–161 | Cite as

Smallholder Farms as Stepping Stone Corridors for Crop-Raiding Elephant in Northern Tanzania: Integration of Bayesian Expert System and Network Simulator

  • Claudia Pittiglio
  • Andrew K. Skidmore
  • Hein A. M. J. van Gils
  • Michael K. McCall
  • Herbert H. T. Prins


Crop-raiding elephants affect local livelihoods, undermining conservation efforts. Yet, crop-raiding patterns are poorly understood, making prediction and protection difficult. We hypothesized that raiding elephants use corridors between daytime refuges and farmland. Elephant counts, crop-raiding records, household surveys, Bayesian expert system, and least-cost path simulation were used to predict four alternative categories of daily corridors: (1) footpaths, (2) dry river beds, (3) stepping stones along scattered small farms, and (4) trajectories of shortest distance to refuges. The corridor alignments were compared in terms of their minimum cumulative resistance to elephant movement and related to crop-raiding zones quantified by a kernel density function. The “stepping stone” corridors predicted the crop-raiding patterns. Elephant presence was confirmed along these corridors, demonstrating that small farms located between refuges and contiguous farmland increase habitat connectivity for elephant. Our analysis successfully predicted elephant occurrence in farmland where daytime counts failed to detect nocturnal presence. These results have conservation management implications.


Ecological corridors Bayesian expert system Human–elephant conflict Crop damage control Farms Movement behavior 



This research was funded by the University of Twente, Faculty of Geo-Information Science and Earth Observation (ITC), The Netherlands, and the Global Environment Facility Project GCP/URT/124/WBG. The authors would like to thank the Food and Agriculture Organization of the United Nations (FAO), the Livestock, Environment and Development Initiative (LEAD), the African Wildlife Foundation (AWF), and the canvassers for their support to the crop-raiding data collection. The authors also thank the GEF project for providing the GIS layers used in this analysis and Istituto Oikos for providing the validation dataset.

Supplementary material

13280_2013_437_MOESM1_ESM.pdf (399 kb)
Supplementary material 1 (PDF 399 kb)


  1. Allison, P.D. 1999. Logistic regression using the SAS system: Theory and applications. Cary, NC: SAS Institute Inc.Google Scholar
  2. Bennett, G., and K.J. Mulongoy. 2006. Review of experience with ecological networks, corridors and buffer zones. Montreal: Secretariat of the Convention on Biological Diversity.Google Scholar
  3. Beyer, H.L. 2004. Hawth’s analysis tools for ArcGIS. From
  4. Chetkiewicz, C.L.B., C.C.S. Clair, and M.S. Boyce. 2006. Corridors for conservation: Integrating pattern and process. Annual Review of Ecology Evolution and Systematics 37: 317–342.CrossRefGoogle Scholar
  5. Chiyo, P.I., E.P. Cochrane, L. Naughton, and G.I. Basuta. 2005. Temporal patterns of crop raiding by elephants: A response to changes in forage quality or crop availability? African Journal of Ecology 43: 48–55.CrossRefGoogle Scholar
  6. Conover, W.J., and R.L. Iman. 1981. Rank transformations as a bridge between parametric and nonparametric statistics. The American Statistician 35: 124–129.Google Scholar
  7. Edkins, M.T., L.M. Kruger, K. Harris, and J.J. Midgley. 2008. Baobabs and elephants in Kruger National Park: Nowhere to hide. African Journal of Ecology 46: 119–125.CrossRefGoogle Scholar
  8. Fischer, J., and D.B. Lindenmayer. 2002. The conservation value of paddock trees for birds in a variegated landscape in southern New South Wales. 2. Paddock trees as stepping stones. Biodiversity and Conservation 11: 833–849.CrossRefGoogle Scholar
  9. Galanti, V., D. Preatoni, A. Martinoli, L.A. Wauters, and G. Tosi. 2006. Space and habitat use of the African elephant in the Tarangire–Manyara ecosystem, Tanzania: Implications for conservation. Mammalian Biology 71: 99–114.CrossRefGoogle Scholar
  10. Graham, M.D., I. Douglas-Hamilton, W.M. Adams, and P.C. Lee. 2009. The movement of African elephants in a human-dominated land-use mosaic. Animal Conservation 12: 445–455.CrossRefGoogle Scholar
  11. Graham, C.H., J. VanDerWal, S.J. Phillips, C. Moritz, and S.E. Williams. 2010a. Dynamic refugia and species persistence: Tracking spatial shifts in habitat through time. Ecography 33: 1062–1069.CrossRefGoogle Scholar
  12. Graham, M.D., B. Notter, W.M. Adams, P.C. Lee, and T.N. Ochieng. 2010b. Patterns of crop-raiding by elephants, Loxodonta africana, in Laikipia, Kenya, and the management of human–elephant conflict. Systematics and Biodiversity 8: 435–445.CrossRefGoogle Scholar
  13. Haddad, N. 2000. Corridor length and patch colonization by a butterfly, Junonia coenia. Conservation Biology 14: 738–745.CrossRefGoogle Scholar
  14. Hanski, I. 1998. Metapopulation dynamics. Nature 396: 41–49.CrossRefGoogle Scholar
  15. Hebblewhite, M., and D.T. Haydon. 2010. Distinguishing technology from biology: A critical review of the use of GPS telemetry data in ecology. Philosophical Transactions of the Royal Society B-Biological Sciences 365: 2303–2312.CrossRefGoogle Scholar
  16. Hill, C., F. Osborn, and A.J. Plumptre. (Eds.). 2002. Humanwildlife conflict: Identifying the problem and possible solutions. Bronx: Wildlife Conservation Society.Google Scholar
  17. Hoare, R.E. 1999a. Data collection and analysis protocol for human–elephant conflict situations in Africa. A document prepared for the IUCN African Specialist Group’s Human–Elephant Conflict Working Group. Arusha: International Union for Conservation of Nature (IUCN).Google Scholar
  18. Hoare, R.E. 1999b. Determinants of human–elephant conflict in a land-use mosaic. Journal of Applied Ecology 36: 689–700.CrossRefGoogle Scholar
  19. Hoare, R. 2000. African elephants and humans in conflict: The outlook for co-existence. Oryx 34: 34–38.Google Scholar
  20. Horne, J.S., and E.O. Garton. 2006. Likelihood cross-validation versus least squares cross-validation for choosing the smoothing parameter in Kernel home-range analysis. Journal of Wildlife Management 70: 641–648.CrossRefGoogle Scholar
  21. Horne, J.S., and E.O. Garton. 2009. Animal Space Use 1.3. Google Scholar
  22. Kahurananga, J. 1979. The vegetation of the Simanjiro Plains, Northern Tanzania. African Journal of Ecology 17: 65–83.CrossRefGoogle Scholar
  23. Kaswamila, A. 2009. Human–wildlife conflicts in Monduli District, Tanzania. International Journal of Biodiversity Science & Management 5: 199–207.CrossRefGoogle Scholar
  24. Kernohan, B.J., R.A. Gitzen, and J.J. Millspaugh. 2001. Analysis of animal space use and movements. In Radio tracking animal populations, ed. J.J. Millspaugh, and J.M. Marzluff, 125–166. New York: Academic Press.CrossRefGoogle Scholar
  25. Kibebe, J.D.N. 2005. Socio-economic and ecological impacts of safari hunting and commercial farming on key stakeholders; Simanjiro District—Tanzania. Oslo: Noragric, Norwegian University of Life Sciences.Google Scholar
  26. Kikoti, A.P. 2009. Seasonal home range sizes, transboundary movements and conservation of elephants in northern Tanzania. Paper: Open Access Dissertations. 108.Google Scholar
  27. Kramer-Schadt, S., T.S. Kaiser, K. Frank, and T. Wiegand. 2011. Analyzing the effect of stepping stones on target patch colonisation in structured landscapes for Eurasian lynx. Landscape Ecology 26: 501–513.CrossRefGoogle Scholar
  28. Krueger, T., T. Page, K. Hubacek, L. Smith, and K. Hiscock. 2012. The role of expert opinion in environmental modelling. Environmental Modelling & Software 36: 4–18.CrossRefGoogle Scholar
  29. Lamarque, F., J. Anderson, R. Fergusson, M. Lagrange, Y. Osei-Owusu, and L. Bakker. 2009. Human–wildlife conflict in Africa. Causes, consequences and management strategies. Rome: FAO.Google Scholar
  30. Landguth, E.L., B.K. Hand, J. Glassy, S.A. Cushman, and M.A. Sawaya. 2012. UNICOR: A species connectivity and corridor network simulator. Ecography 35: 9–14.CrossRefGoogle Scholar
  31. Lobora, A.L. 2010. Tanzania elephant management plan 2010-2015. Arusha: Tanzania Wildlife Research Institute.Google Scholar
  32. Msoffe, F., F. Mturi, V. Galanti, W. Tosi, L. Wauters, and G. Tosi. 2007. Comparing data of different survey methods for sustainable wildlife management in hunting areas: The case of Tarangire–Manyara ecosystem, northern Tanzania. European Journal of Wildlife Research 53: 112–124.CrossRefGoogle Scholar
  33. Murray, J.V., A.W. Goldizen, R.A. O’Leary, C.A. McAlpine, H.P. Possingham, and S.L. Choy. 2009. How useful is expert opinion for predicting the distribution of a species within and beyond the region of expertise? A case study using brush-tailed rock-wallabies Petrogale penicillata. Journal of Applied Ecology 46: 842–851.CrossRefGoogle Scholar
  34. National Bureau of Statistics Tanzania. 2006. 2002 population and housing census report, Dar Es Salaam.Google Scholar
  35. Naughton, L., R. Rose, and T. Treves. 1999. The social dimensions of human–elephant conflict in Africa: A literature review and case studies from Uganda and Cameroon. Human–elephant conflict task force. Gland, Switzerland: IUCN.Google Scholar
  36. Naughton-Treves, L. 1998. Predicting patterns of crop damage by wildlife around Kibale National Park, Uganda. Conservation Biology 12: 156–168.CrossRefGoogle Scholar
  37. Newmark, W.D., D.N. Manyanza, D.-G.M. Gamassa, and H.I. Sariko. 1994. The conflict between wildlife and local people living adjacent to protected areas in Tanzania: Human density as a predictor. Conservation Biology 8: 249–255.CrossRefGoogle Scholar
  38. Ngene, S.M., H. Van Gils, S.E. Van Wieren, H. Rasmussen, A.K. Skidmore, H.H.T. Prins, A.G. Toxopeus, P. Omondi, et al. 2010. The ranging patterns of elephants in Marsabit protected area, Kenya: The use of satellite-linked GPS collars. African Journal of Ecology 48: 386–400.Google Scholar
  39. Oikos. 2002. Tarangire Manyara Conservation Project. Final report, Arusha, Tanzania.Google Scholar
  40. Osborn, F.V., and G.E. Parker. 2002. Community-based methods to reduce crop loss to elephants: Experiments in the communal lands of Zimbabwe. Pachyderm 33: 32–38.Google Scholar
  41. Pinto, N., and T. Keitt. 2009. Beyond the least-cost path: Evaluating corridor redundancy using a graph-theoretic approach. Landscape Ecology 24: 253–266.CrossRefGoogle Scholar
  42. Pittiglio, C., A.K. Skidmore, H.A.M.J. van Gils, and H.H.T. Prins. 2012. Identifying transit corridors for elephant using a long time-series. International Journal of Applied Earth Observation and Geoinformation 14: 61–72.CrossRefGoogle Scholar
  43. Pittiglio, C., A.K. Skidmore, H.A.M.J. van Gils, and H.H.T. Prins. 2013. Elephant response to spatial heterogeneity in a savanna landscape of northern Tanzania. Ecography 36: 819–831.Google Scholar
  44. Prins, H.H.T. 1987. Nature conservation as an integral part of optimal land use in East Africa: The case of the Masai ecosystem of Northern Tanzania. Biological Conservation 40: 141–161.CrossRefGoogle Scholar
  45. Silverman, B.W. 1986. Density estimation for statistics and data analysis. London: Chapman and Hall.CrossRefGoogle Scholar
  46. Sitati, N.W., M.J. Walpole, R.J. Smith, and N. Leader-Williams. 2003. Predicting spatial aspects of human–elephant conflict. Journal of Applied Ecology 40: 667–677.CrossRefGoogle Scholar
  47. Sitati, N.W., M.J. Walpole, and N. Leader-Williams. 2005. Factors affecting susceptibility of farms to crop raiding by African elephants: Using a predictive model to mitigate conflict. Journal of Applied Ecology 42: 1175–1182.CrossRefGoogle Scholar
  48. Skidmore, A.K. 1989. An expert system classifies Eucalypt forest types using thematic mapper data and digital terrain model. Photogrammetric Engineering & Remote Sensing 55: 1449–1464.Google Scholar
  49. Smith, R.J., and S.M. Kasiki. 2000. A spatial analysis of human–elephant conflict in the Tsavo ecosystem, Kenya. Gland: African Elephant Specialist Group, Human–Elephant Conflict Task Force.Google Scholar
  50. Uezu, A., D.D. Beyer, and J.P. Metzger. 2008. Can agroforest woodlots work as stepping stones for birds in the Atlantic forest region? Biodiversity and Conservation 17: 1907–1922.CrossRefGoogle Scholar
  51. Voinov, A., and F. Bousquet. 2010. Modelling with stakeholders. Environmental Modelling & Software 25: 1268–1281.CrossRefGoogle Scholar
  52. Vos, C.C. 1999. A frog’s-eye view of the landscape. PhD Thesis. Wageningen: Wageningen University.Google Scholar
  53. Wall, J., I. Douglas-Hamilton, and F. Vollrath. 2006. Elephants avoid costly mountaineering. Current Biology 16: R527–R529.CrossRefGoogle Scholar

Copyright information

© Royal Swedish Academy of Sciences 2013

Authors and Affiliations

  • Claudia Pittiglio
    • 1
  • Andrew K. Skidmore
    • 1
  • Hein A. M. J. van Gils
    • 1
  • Michael K. McCall
    • 2
    • 3
  • Herbert H. T. Prins
    • 4
  1. 1.Department of Natural Resources, Faculty of Geo-Information Science and Earth Observation (ITC)University of TwenteEnschedeThe Netherlands
  2. 2.Department of Urban and Regional Planning and Geo-Information Management, Faculty of Geo-Information Science and Earth Observation (ITC)University of TwenteEnschedeThe Netherlands
  3. 3.Centro de Investigaciones en Geografía Ambiental (CIGA)Universidad Nacional Autónoma de México (UNAM)MoreliaMexico
  4. 4.Resource Ecology GroupWageningen UniversityWageningenThe Netherlands

Personalised recommendations