Changes in the food supply capacity of alpine grassland ecosystem:A dialectic synthesis of natural and anthropogenic drivers

Grassland-based animal husbandry and livestock production is the main contributor to livelihood creation for herdsmen.By using the structural dynamics method,this study quantified the changes in the food supply capacity(FSC)of alpine grassland ecosystem and sensitivity to significant variables.The findings indicated that:i)Natural factors were the dominated forces affecting FSC,and their contribution was 71.3%.Of these natural elements,the net primary productivity(NPP)and precipitation were the largest contributors,accounting for approximately 35%.The sensitivity index of the FSC to NPP and precipitation during grassland growing season were 4.1 and 1.9 respectively.On the contrary,human factors like warm shed area,density of road,capacity for access to information,contributed to 28.7%of the total FSC.ii)More intense snow disaster had a larger negative impact on FSC.Snow disaster can cause dramatic reduction in FSC,with a loss rate of 27.6%and with none intense disaster more negative impacts,iii)The continuing increase of FSC in the past 30 years from 1984 to 2014 was due to the significant increase of precipitation and NPP in the growing season of alpine grassland.Evidently,successful adaptation to climate change was critical to combat the climatic adversely impact on FSC.Typically,strengthening information dissemination,road accessibility and knowledge popularization of local residents'disaster reduction should be place high priority for improving FSC。