Using presence-only modelling to predict Asian elephant habitat use in a tropical forest landscape: implications for conservation

Authors

  • Ente Rood,

    Corresponding author
    1. Department of Anthropology and Geography, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
    2. Netherlands Centre for Biodiversity Naturalis (section ZMA), Mauritskade 61, 1092 AD Amsterdam, The Netherlands
    3. Fauna and Flora International-Indonesia Programme, Jalan Arifin Ahmad 3, Banda Aceh, Indonesia
      Correspondence: Ente Rood, Department of Anthropology and Geography, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK.
      E-mail: enterood@gmail.com
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  • Abdullah A. Ganie,

    1. Fauna and Flora International-Indonesia Programme, Jalan Arifin Ahmad 3, Banda Aceh, Indonesia
    2. School of Life Sciences and Technology, Institut Teknologi Bandung, 10, Jalan Ganesa, Bandung 40132, Indonesia
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  • Vincent Nijman

    1. Department of Anthropology and Geography, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
    2. Netherlands Centre for Biodiversity Naturalis (section ZMA), Mauritskade 61, 1092 AD Amsterdam, The Netherlands
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Correspondence: Ente Rood, Department of Anthropology and Geography, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK.
E-mail: enterood@gmail.com

Abstract

Aim  Asian elephants, Elephas maximus, are threatened throughout their range by a combination of logging, large scale forest conversion and conflict with humans. We investigate which environmental factors, both biotic and abiotic, constrain the current distribution of elephants. A spatially explicit habitat model is constructed to find core areas for conservation and to assess current threats.

Location  Ulu Masen Ecosystem in the province of Nanggroe Aceh Darussalam on the island of Sumatra, Indonesia.

Methods  A stratified survey was conducted at 12 sites (300 transects) to establish the presence of elephants. Presence records formed the basis to model potential habitat use. Ecological niche factor analysis (ENFA) is used to describe their niche and to identify key factors shaping elephant distribution. An initial niche model was constructed to describe elephant niche structure, and a second model focused on identifying core areas only. To assess the threat of habitat encroachment, overlap between the elephants’ optimal niche and the occurrence of forest encroachment is computed.

Results  Elephants were recorded throughout the study area from sea level to 1600 m a.s.l. The results show that the elephant niche and consequently habitat use markedly deviates from the available environment. Elephant presence was positively related to forest cover and vegetation productivity, and elephants were largely confined to valleys. A spatially explicit model showed that elephants mainly utilize forest edges. Forest encroachment occurs throughout the elephants range and was found within 80% of the elephants’ ecological niche.

Main conclusions  In contrast to general opinion, elephant distribution proved to be weakly constrained by altitude, possibly because of movement routes running through mountainous areas. Elephants were often found to occupy habitat patches in and near human-dominated areas. This pattern is believed to reflect the displacement of elephants from their former habitat.

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