Research Of The Structure And Nutrition Of Bamboo In Qinling Mountains And The Relationship With Seasonal Distribution Of Giant Pandas

This study studied three staple food bamboo species(Fargesia qinlingensis, Bashania fargesii and Fargesia dracocephala), samples of each plant were taken from the south slope of the Qinling Mountains in Shaanxi Province, China. The bamboo height, bamboo basal diameter, bamboo density, and the content of seven kinds of mineral nutrition(Cu,Zn,Fe,Mn,K,Ca,Mg) and four kinds of conventional nutrition(crude protein, crude fat, crude fiber, sugar) were measured. The effects of bamboo species, the part of the bamboo plant, elevation, and season on the sturcture of the bamboo forest and its nutrition were calculated. In this paper, the giant pandas’ seasonal migration and the staple food bamboo nutrition were combined, using a Random Forest model to test the statistical significance of each nutrition index, and thus its importance. Our results indicate that:1. Significant difference exist among the three bamboo species with regard to bamboo height, basal diameter and the density of the bamboo forest. Bashania fargesii had the greatest basal diameter and bamboo height, Fargesia qinlingensis had the maximum density; Fargesia dracocephala had the largest degree of statistical uniformity and evenness. Among the three elevation gradients at which Fargesia qinlingensis was tested, the middle elevation had the maximum bamboo height, bamboo basal diameter and uniformity; the high elevation zone had the greatest evenness and bamboo density. Bashania fargesii had the greatest bamboo height, bamboo basal diameter, evenness at low elevation and the largest degree of uniformity in the transition elevation zone. Fargesia qinlingensis and Bashania fargesii both had the smallest bamboo height and bamboo basal diameter in the transition elevation zone. Bashania fargesii in the low elevation zone had the highest correlation between bamboo height and bamboo basal diameter, and Fargesia dracocephala in the low elevation zone had the lowest correlation value.2. In our study 11 nutrition indices were tested: crude protein, crude fat, crude fiber, sugar, Cu,Zn,Fe,Mn,K,Ca,and Mg. Then mean values of these eleven indices were 5.63%, 3.51%, 43.60%, 1.85%, 11.72 mg/kg, 21.12 mg/kg, 269.85 mg/kg, 208.53 mg/kg, 7917.11 mg/kg, 3178.11 mg/kg, and 1381.72 mg/kg respectively. Bashania fargesii had the highest nutritional content among the three bamboo species; the Mn content of Bashania fargesii and sugar content of Fargesia dracocephala in the low elevation zone were significant higher than at other elevations, and in the low elevation zone these bamboos also had the highest nutritional content, spring was the season which the bamboos had greatest nutritional value, followed by autumn and summer; the leaf was the most nutritious part of the plant, followed by the branch, shoot, culm and one year culm. Across the six different elevation groups, the following trends were observed: Cu, Zn, and crude fat were highest in spring; crude fiber was lowest in spring; Fe was highest in summer; Mn, and Mg were highest in autumn. Comparing the nutritional value among different elevations in three seasons, we found that Fargesia dracocephala and Bashania fargesii in the low elevation zone and Fargesia qinlingensis in the high elevation zone were superior sources of food for giant pandas. However in autumn the advantages of Fargesia dracocephala and Bashania fargesii at low elevation were not obvious.3. The elevations of summer and winter habitats selected by giant pandas were significantly different. Our Random Forest model showed that crude protein, Mn, and Mg had significant effect on giant pandas’ migration patterns over the whole year. The nutritional value of shoots in spring and summer were both highly significant in deciding panda habitat selection habits.In this study, significant differences were found in bamboo height, bamboo basal diameter and density of the bamboo forest among the three staple food bamboo species tested. In addition the structural indices of the transition zone were lower than in other elevation zones. Bashania fargesii had the highest nutritional value compared to the other two species of bamboo; spring was the best season among the three seasons investigated for nutrition; the leaf part of bamboo plant also offered the best sustenance; Bashania fargesii and Fargesia dracocephala in low elevation zone had the best nutritional content among all the elevation zones. Finally, the three nutrients crude protein, Mn and Mg had an important influence on giant pandas’ seasonal migration trends.