陕北地区土地利用变化对生态服务功能价值的影响

以陕北地区榆林、延安2市作为研究区域,利用土地利用变化数据,对陕北地区用地类型的变化进行分析,并使用合适的生物量因子,修正生态服务功能价值当量表,使当量表更符合陕北地区的实际情况,结合已有研究得到的二级用地类型当量因子比例关系,细化生态系统服务功能当量因子表,以便更准确的估算陕北地区生态系统服务功能价值.结果表明:1985-2013年间,主要用地类型变化为耕地、林地和草地,耕地面积减少2 811 km2,减少率达到9.98％,林地和草地面积分别增加1 392和2417 km2,增幅分别达到12.85％和7.10％;其中,2000-2013年面积急剧变化,林地和草地面积的增加量分别是1985-2000年的7倍和2倍,退耕还林(草)效果明显;生态系统服务功能价值大量增加,林地和草地的生态系统服务功能价值增量分别为25.2亿和13.9亿元,2000-2013年的增量是1985-2000年增量的3倍.生态服务功能价值的变化与全面推行退耕还林(草)的时间相对应,表明退耕还林(草)政策,对陕北地区生态系统服务功能价值有积极的影响.

Impact of land use change on ecosystem services value in northern Shaanxi

[Background] In hilly-gullied area of northern Shaanxi,the soil and water erosion is serious,Returning Farmland into Forest and Grassland is an important policy to improve the environment,brings great positive changes to the ecological environment.Northern Shaanxi including Yulin and Yan'an is one of the serious soil erosion regions,thus northern Shaanxi was selected as the pilot area to implement the policy of Returning Farmland into Forest and Grassland in 1999,and it was completely proceeded in 2002.To study the impact effects of this policy,this research focused on the ecosystem service value (ESV) of northern Shaanxi affected by this policy,and analyzed the characteristics of the ESV changing pattern of northern Shaanxi.[Methods] The studied area of northern Shaanxi is located at E 107°15'-110°15'and N 35°02'-39°35.The data was from the database of 1:10 land use in China in 2013.The ESV equivalent coefficient per unit area of northern Shaanxi terrestrial ecosystem was firstly revised by appropriate biomass factors,and then refined using the proportional relation between type of land use and subtype of land use.The ESV per unit area of northern Shaanxi terrestrial ecosystem was calculated by grain production.Then ESV was calculated by multiplying the area of different type of land use in northern Shaanxi by ESV per unit area.[Results] 1) In northern Shaanxi,the land-use change occurred in the cultivated land,the forest and grassland,the cultivated land area reduced by 2 811 km2 from 1985 to 2013,the rate of change was-9.98％.The area of forest and grassland increased by 1 392 km2 and 2 417 km2 respectively in 1985-2013,the rate of change was 12.85％ and 7.10％,respectively.The areas changed clearly in 2000-2013,the areas increment of forest and grassland in 2000-2013 was 7 times and 2 times of that in 1985-2000 respectively.The construction of land use in northern Shaanxi was observably influenced by the policy of Returning Farmland into Forest and Grassland.2) The ESV of northern Shaanxi was improved clearly in 1985-2013,the ESV increment of forest and grassland was 2.52 billion and 1.39 billion Yuan respectively,the increment of 2000-2013 was three times of the increment of 1985-2000.[Conclusions] The ESV transformation of forest,grassland and arable land was drastic in 2000-2013,it was corresponding to the time of Returning Farmland into Forest and Grassland energetically,and the ESV perunit area of northern Shaanxi terrestrial ecosystem is positively influenced by the policy of Returning Farmland into Forest and Grassland.