Effects of tannin and nutrient elements in three species of staple food bamboo on giant panda herbivory tendency.

To study the effects of tannin and nutrient elements in bamboo species and different parts on giant panda herbivory tendency, after field survey, samples from three species of staple food bamboo Bashania fangiana, Fargesia robusta, and Phyllostachys bissetii for giant panda from Anzihe Nature Reserve in Qionglai Mountain, southwestern China were collected. The contents of tannin, crude protein and some mineral elements, such as Ca, Mg, Zn, Cu, were measured. The correlations between the tendency of herbivory and tannin and other nutrient elements among different species, varied vegetative organs and different parts were analyzed. The conclusions were as follows: 1) B. fangiana had the lowest tannin content while F. robusta had the highest, and the tannin content in stem was the lowest when compared with other parts for all of the three. 2) In terms of some nutrient elements, significant differences among these three species were identified, and the B. fangiana had the highest content of crude protein while F. robusta had the lowest; and the correlations between the content of crude protein and Zn and the average height of stumps of culms grazed by panda were negative. 3) Giant panda preferred to eat the species and the sites of bamboo which contained lower tannin and higher crude protein; the content of tannin and crude protein can be considered as important factors for giant panda to select the species and the sites of bamboo.