Spatiotemporal Variation Of Ecological Assets And Its Driving Factors In Shaanxi Section Of Qinling Mountains,China

As an important geographical demarcation and ecological barrier in China,Qinling Mountains has extremely significant geographical significance and scientific research value.Ecological asset as a green GDP,accounting for its value is a means to clarify regional ecological health and environmental carrying capacity.By monitoring dynamic changes and driving mechanisms of ecological assets can provide a reference for regional sustainable development,government decision-making and real-time early warning for preventing ecological risks.Based on the theory and method of remote sensing estimation of ecological assets,this paper obtains ecological parameters such as land cover,net primary productivity（NPP）,biomass and vegetation coverage,and uses a series of engineering technologies such as market value method,alternative engineering method,and shadow engineering method to obtain the value of natural resources,production of organic matter,atmospheric regulation,conservation of water resources,conservation of soil value and nutritional value,then the six ecological asset components were spatially superimposed to obtain the spatial distribution of ecological assets in the Qinling Mountains,and its driving mechanisms were analyzed.The results of the study are as follows:（1）On the type scale,largest patch index（LPI）of the forest land is higher than other land types,the forest land has obvious advantages,followed by grassland and farmland.The patch density（PD）of cultivated land is higher than other land types,and there are more patches in unit area.The landscape shape index（LSI）of grassland,cultivated land,and forest land is relatively high,and its boundaries are irregularly distributed due to topography and other restrictions,while construction land and others are more regular.The landscape division index（DIVISION）of arable land and unused land is relatively high,the arable land is mainly due to the unique topography of the Qinling Mountains,which leads to its scattered distribution,while the unused land is less distributed and not concentrated.The aggregation index（AI）of forest land is the highest,combined with LPI index,indicating that the distribution of forest land in the Qinling Mountains is continuous;on the landscape scale,the PD,LPI,and DIVISION indices do not have continuous upward and downward trends,and the overall landscape pattern of the Qinling Mountains does not change drastically.（2）NPP in Qinling Mountains during three years generally shows a spatial pattern of low in the east and high in the west.Its value above 400 g C·m^-2·a^-1 accounts for 63.39%,82.46%,and 66.58%of the total area,respectively.Accumulation is good.The spatial distribution pattern of NPP in biomass and vegetation in the Qinling Mountains are similar.The spatial structure characteristics are basically isotropy.The southwestern biomass area is significantly higher than that in the northeastern region.The eastern region has a pattern of high and low values due to the complex fragmentation of the land types.The coverage of vegetation in the Qinling Mountains is basically greater than 0.5,and the vegetation coverage is high.（3）For Qinling Mountains,the value of natural resources contributed by the vegetation was the highest（25.04%）,the mean value of 3a was 820.25×10⁸ yuan,and the value of conservation soil（20.56%）and the value of conservation water（20.50%）contribution is about the same,and the average value of 3a is673.66×10⁸ yuan and 671.78×10⁸ yuan respectively.The proportion of value of atmospheric regulation accounts for 18.51%,and the average value of 3a is 606.40×10⁸ yuan.The proportion of nutritional value accounts for 12.84%,and the average value of 3a is 420.55×10⁸ yuan.The contribution of organic matter production is the lowest,accounting for 2.55%,and the mean value of 3a is 83.76×10⁸ yuan.（4）The value of ecological assets of the Qinling Mountains in 2005,2010,and 2015 were 3330.60×10⁸yuan,3580.57×10⁸ yuan,and 2787.81×10⁸ yuan,respectively,and the average value of the 3a was 4.46×10⁴yuan/hm²,4.78×10⁴ yuan/hm²,3.74×10⁴ yuan/hm²,the high value of ecological assets is mainly distributed in the southern part of the Qinling Mountains,while the low value is distributed in the northern part of the Qinling Mountains,and gradually decreases from the south to the north.（5）Among the driving factors of the ecological structure of the Qinling Mountains,natural factors have a stronger driving effect on ecological assets than social human factors.The correlation coefficients between rainfall and temperature and ecological assets are 0.544 and 0.431,respectively,and all have significant positive correlations.Under the conditions,due to the differences in solar radiation and rainfall received,there is a pattern of topographic differentiation in the ecological asset pattern.There is a complex and nonlinear negative correlation between social economic factors and ecological assets.The driving forces of human activities on ecological assets are positive accumulation（such as returning farmland to forests and grasslands,various types of shelterbelt projects,and greening along highways,etc.）,and reverse losses（such as the destruction of surrounding vegetation caused by urban expansion,regional natural resources development,etc.）.