Affiliation: | The Agricultural University of Norway, Noragric Centre for International Environment and Development Studies, Tivoli, PO Box 5001, N-1432 Ås, Norway;;Centre for Development Studies, University of Bergen, Stroemgt., 54 N-5007, Bergen, Norway;and;Department of Biology, Division of Zoology, University of Oslo, PO 1050 Blindern, N-0316 Oslo, Norway |