The Effects Of Wild Giant Panda Grazing On The Clone Growth Of Arundinaria Spanostachya (Yi) Li

In order to explore the response mechanism of clonal population of Arundinaria spanostachya to grazing by wild giant panda and the coevolution mechanism between bamboo and giant panda, the regeneration dynamics, spatial structure variation and biomass allocation of the clonal population of A. spanostachya in the habitat of wild giant panda in Liziping Nature Reserve was investigated based on the quadrate method and positioning observation method in 2014~2015a, and the indexes such as new shoot quality, recruitment rate, and mortality rate and degraded shoot rate were analyzed before and after grazing by giant panda, and the sustainable utilization of A.spanostachya was discussed. The results are as follows.(1)The wild giant panda in Liziping nature reserve would evade feeding the bamboo with the basal diameter of below 6mm, and also cannot feed the bamboo with bigger basal diamenter, while preferred the medium size bamboo with the mean basal diameter of 11.48±0.21 mm. After grazed, there was no significant difference in the basal diameter between the new bamboo and the remnant stakes. The basal diameter size of new bamboo was similar to that before grazed by giant panda, indicating that the new bamboo shoots still met the criteria for feeding by wild giant panda.(2)The recruitment rate and shooting quantity of clonal population of A.spanostachya was improved after grazed by giant panda, which promoted the regeneration of the clonal population. In the first year after grazed by giant panda, the recruitment rate in grazed plots was significantly higher than the mortality rate and that in control plots, and the density of new shoots was also significantly higher than that in control plots, while there was no significant effect on the basal diameter and the height of new bamboo.(3) In The first year(2014a) after grazed by giant panda, the population density of different age in grazed plots and control plots was the same as that before grazed, and the order was the perennial > anunal > biennial; while in the second year(2015a), it presented the different character: the perennial>biennial>annual. The proportion of population density among different diameter class in grazed plots and control plots was basically the same as that before grazed. There was no significant effect on the diameter-class structure and the height-class structure of the clonal population of A.spanostachya after grazed.(4) Before and after grazed by giant panda, the ramet total biomass among different age of clonal population of A. spanostachya all presented the regular character of the perennial > biennial > annual, and the dry matter content of different modules allpresented the allocation character of stem>branch> leaf. The dry matter content of ramet in A. spanostachya increased with the increase of ramet age. The total water content of ramet among different age of A. spanostachya would decrease with the increase of ramet age. Before and after grazed, the stem water content was also the most.Therefore, the grazing by giant panda had no significant effect on the biomass allocation of clonal population of A. spanostachya.The results showed that:(1) In Liziping nature reserve, the wild giant panda grazing had no effect on the regeneration quantity and quality, the structure of diameter class and height class, and the biomass allocation of the clone population of A.spanostachya, and the clone population of A. spanostachya had adapted to the giant panda grazing.(2) After grazed by giant panda, the clone population of A. spanostachya had great self-adjustment ability to recover the status before grazed by giant panda, and so continuously provided food for giant pandas.