Geffen E, Hefner R, Macdonald DW, Ucko MApril 1993Journal article Journal:OryxVolume:27Issue:2, Cambridge University Press (CUP), pp.104 - 108No abstract availableKeywords:41 Environmental Sciences , 3103 Ecology , 4104 Environmental Management , 31 Biological Sciences DOI10.1017/s0030605300020639