Effects of Wildness Training Giant Pandas’ Grazing and Artifi cial Harvesting on Clone Population Biomass of Umbrella Bamboo ( Fargesia robusta )

Abstract

Giant pandas(Ailuropoda melanoleuca) have evolved to be obligate bamboo grazers,and 99% of their diets consist of subalpine bamboo species.The life span of giant pandas are directly related to the life cycle of the bamboo which pandas feed on,so the regeneration of bamboo is directly linked to survival and conservation of giant pandas.The biomass of population and ramet were used to evaluate the impact of panda foraging and artificial harvesting on the sustainability of umbrella bamboo(Fargesia robusta) in Wolong Nature Reserve,China.From 2003 to 2007,the population density,age,and growth characteristics of F.robusta clone were monitored by the methods of the immobile plot sampling and positioning observation.Three types of plots were located in the reserve: Grazed(bamboo in the wildness training enclosure from July 2003 to September 2004),harvested(bamboo cut in the spring of 2004),and control(no treatments from 2003 to 2007).The simultaneous regressive models of each age-class bamboo and remnant stake biomass in both ways of population and ramet were constructed using the methods of harvest and non-destructive volume estimation.Then the effects of wildness training pandas' grazing and artificial harvesting on the clone population and ramet biomass of F.robustawe were analyzed according to the models.Controlling the demographic,morphologic,population biomass and environmental conditions,panda feeding and artificial harvesting resulted in a reduction of bamboo productivity,and influenced the restoration and development of experimental populations from 2005 to 2007.Compared to the bamboo population biomass in the control plots,the value in panda grazed plots was lower(e.g.bamboo shoot biomass in grazed plots was 57.79% of that in control plots).The ramet biomass of each age-class bamboo was up to the standards of panda feeding,with the exception of 2004 year,and was in capacity of sustainingly providing food resources to pandas.However,the population biomass of F.robusta clone decreased dramatically due to the artificial harvest(e.g.bamboo shoot biomass was 14.69% of that in control plots).Therefore,bamboo shoot and ramet biomass were mainly reason for the qualification for panda grazing.