title: Determinants of orangutan density in the dryland forests of the Leuser Ecosystem.
abstract: Orangutans are the only great ape in Asia. Since orangutan densities vary between habitat types within regions and within similar habitat types among regions, it is important to determine areas with high densities for their protection. In this paper we show that orangutan density in old-growth dryland forests in the Leuser Ecosystem, Sumatra is significantly related to the density of large strangling figs and topsoil pH. In addition, large fig density depends on topsoil pH. Provided that orangutans are present and no hunting or logging occur, topsoil pH seems a promising method for rapid assessment of potential orangutan density over large areas.
authors.affiliation: Behavioural Biology, Utrecht University, P.O. Box 80086, 3508 Utrecht, The Netherlands. sergewich@hetnet.nl
authors.forename: Serge
authors.initials: S
authors.lastname: Wich
authors.forename: Ralph
authors.initials: R
authors.lastname: Buij
authors.forename: Carel
authors.initials: C
authors.lastname: van Schaik
mesh_terms: D000818:Animals; D003247:Conservation of Natural Resources; D017753:Ecosystem; D004777:Environment; D030681:Ficus; D006863:Hydrogen-Ion Concentration; D007214:Indonesia; D016014:Linear Models; D019370:Observation; D011148:Pongo pygmaeus / Q000502:physiology*; D011156:Population Density; D012987:Soil / Q000032:analysis; D014197:Trees
chemical_list: D012987:Soil