| The western black crested gibbon (Nomascus concolor) belongs to the first level national key protected wild animals. Influenced by various of factors, habitat fragmentation of the western black crested gibbon is becoming increasingly serious and the population isolation of the gibbon is becoming increasingly prominent. We chose2small groups of isolated populations of the western black crested gibbon at Bajiaohe in Jinping Yunnan as our research subjects, combining wild observation of foraging behavior, the plant phenology monitoring in the gibbon habitat, and food chemical analysis in laboratory, a preliminary study on nutritional ecology of the western black crested gibbon was conducted for the first time in order to provide scientific reference for the conservation of isolated populations of the gibbons.Through a full year cycle of field behavior observation, the diet structure of the black crested gibbon at Bajiaohe was determined We recorded that the gibbon fed on71plant species and5species of animals. Plant foods are composed of50species of trees,12species of liana,8species of shrubs and one species of herbs, which were identified and assigned to55genera from38families. In all plant species,53species of which are fed by the fruits, the proportion of which is as high as74.65%;18species of which are fed by leaves, buds,4species of which are fed by flowers, with the proportions of25.35%and7.04%respectively. During the observation period, a total of1560records on the feeding behavior of western black crested gibbon were recorded, which included1102of fruit,343of leaves and buds class,25of flowers and48of animals. In the western black crested gibbon annual feeding frequency, the proportion of fruit, leaves and shoots, flowers and animals were70.64%.21.99%,4.10%and3.27%, respectively. The western black crested gibbon at Bajiaohe was more frugivorous in their diet. Annual phenological monitoring data analysis shows that there is a significant correlation between the seasonal changes of feeding habits of the Western black crested gibbon and plant phenology in its habitat. There was only2percent plants fruiting in March and April of the early spring, and as reaching the peak of the plant’s leafing and flowering stages, the gibbon feeding on leaves and flowers was significantly higher than other seasons. When the rainy season comes in May, the fruiting rate of the plant was gradually increased. It reached30%in August, and continued to increase. The most fruit foods available season in September and October for gibbons, the gibbon’s fruit selectivity gradually increased. Except for February to April2011, the proportion of monitored trees in the leaf growing stage is more than50%, which indicates that leaves are the most abundant source of food for gibbons. Influence by the plant phenology, western black crested gibbon seeks for their nutritional balance through changing the foraging strategies.The determination of conventional nutrients and secondary metabolite contents of the60plant samples in the habitat of the western black crested gibbon and comparativly analysis the differences in phytochemicals between the food group and the control group, different plant parts and different seasons. The results showed that the food group, the average moisture content, water-soluble sugars, TNC and PME content were79.22%,16.18%,31.35%and12.47%, significantly higher than69.46%,6.35%16.14%and10.75%of the control group respectively; average contents of NDF and ADF of the control group were63.62%and49.96%, significantly higher than47.38%and35.92%of the food group. The western black crested gibbon prefers to the plant rich in water, water-soluble sugar and energy, and low in NDF and ADF. The level of water, water soluble sugar, TNC, PME, NDF and ADF in plant food are the main factors on food selection between food and nonfood for the western black crested gibbon.The content of protein, water soluble sugars, ash and CP/ADF ratio are significantly different in different parts of the plant food. The average protein content of leaves and buds (21.40%) is significantly higher than that of the fruit (7.53%) and flowers (9.40%)(χ2=18.660, P=0.000<0.05). The average content water-soluble sugar of fruit and flowers (18.77%and16.64%) is significantly higher than the leaf (3.77％)(χ2=10.006,,P=0.007<0.05)；The average content of ash of leaves(7.06％)is significantly higher than that of the fruit(4.23％)(χ2=6.633,P=0.036<0.05).T11e Pr／ADF ratio of leaves is0.54,signifocantly higher than0.25that of the fruits and f;owers(χ2=14.181,P=0.001<0.05).Plant young leaves are rich in protein and ash,and the ripe fruits are rich in water-soluble sugars.The western black crested gibbon ingests different nutrients by feeding on different plant parts.The correlative analysis of food nutrients and the proportion of annual feeding records of the black cresed crown gibbon,showed that water(rs=0.197,P=0.298>0.05),protein(rs=0.119,P=0.518>0.05),lipid(rs=0.038,P=0.838>0.05),water soluble sugar(rs=0.117,P=0.523>0.05),NDF(rs=0.071,P=0.699>0.05),ADF (rs=0.016,P=0.932>0.05),ADL(rs=0.167,P=0.362>0.05),ash(rs=0.229,P=0.207>0.05),TNC(rs=0.052,P=0.778>0.05),PME(rs=0.106,P=0.562>0.05), tannin(rs=0.039,P=0.833>0.05)and Pr／ADF ratio(rs=0.030,P=0.699>0.05). The results shown that there was no significant correlation between the12nutrional indexes and the proportion of annual feeding records of the gibbons.It suggested that the preference to different foods was not influenced by the food nutrients for the black crested gibbon at Bajiaohe. |
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