Carbon and nitrogen isotopic characterization for Papua New Guinea foods

Abstract
Stable carbon and nitrogen isotope ratios of the animal and plant food of the Gidra, who inhabit lowland Papua New Guinea and subsist mainly on hunting, gathering and horticulture, were measured to characterize the nutritional input of carbon and nitrogen of the Gidra. All the staple plant foods of the Gidra, such as sago and tuberous crops, were classified as C3 plants from their 13C/12C ratios (δ13C). The δ13C of the terrestrial mammals varied to a considerable extent (—11 to —26.5 per mil); the highest value was observed for a species of wallaby inhabiting savanna grassland while two other species of wallabies inhabiting woodland were —25.3 and —22.8 per mil. The δ13C of the aquatic animals was distinctive between marine (—17.0 to —7.1 per mil) and freshwater (—34.6 to —24.0 per mil) groups. The δ15N of the fishes and reptiles were generally higher than terrestrial animals. Major foods of the Gidra were isotopically divided into 5 groups: C3 plant, C3 plant feeder, C4 plant feeder, marine animal and freshwater animal.