基于三角图法的榆林市农业生态系统脆弱性类型变化研究

Type variability research of agro-ecosystem vulnerability in Yulin,Shaanxi,China,based on triangle method

农业生态系统是农业可持续发展的基础,在全球气候变化引发的生态系统脆弱化背景下,开展农业生态系统脆弱性研究对今后制定区域农业生态环境发展政策、实现农业生态系统可持续发展具有重要的现实意义。以陕西省榆林市12个县(区)为研究单元,从农业环境子系统、生产投入子系统和社会经济子系统中选取24项指标构建农业生态系统脆弱性评价体系,运用赋权法、熵值法、综合指数法等数学方法,结合ArcGIS10.2、Grapher12软件,对2004-2017年榆林市农业生态系统脆弱性类型的演变特征分3个阶段研究,并选取2004、2009、2013、2017年4个具有代表性阶段的起始点作为断面节点,运用三角图法分析榆林市12个县(区)农业生态系统脆弱性类型的演变状况。结果表明:2004-2017年榆林市形成了5型农业生态系统脆弱性:(1)农业环境-生产投入-社会经济子系统均衡脆弱型(EPS型);(2)生产投入-社会经济子系统脆弱型(PS型);(3)农业环境-生产投入-社会经济子系统均衡脆弱型向生产投入-社会经济子系统脆弱型,再到农业环境-生产投入-社会经济子系统均衡脆弱型转变(EPS型→PS型→EPS型);(4)农业环境-生产投入-社会经济子系统均衡脆弱型向生产投入-社会经济子系统脆弱型转变(EPS型→PS型);(5)生产投入-社会经济子系统脆弱型向农业环境-生产投入-社会经济子系统均衡脆弱型转变(PS型→EPS型)。各子系统脆弱性程度在各个发展阶段均呈现出南部区域高于北部区域、南6县高于北6县的分布格局,与该地区农业生态环境的实际发展情况基本一致,但区域农业生态系统脆弱性程度总体上表现出逐年降低的趋势,表明了随着社会经济的不断发展,对农业生产和农业科技水平投入的增加,区域内抵抗农业生态系统脆弱性的能力也得到提升。

Agroecosystem is the premise and foundation of agricultural sustainable development.Under the background of ecosystem weakening caused by global climate change,the research on the vulnerability of agricultural ecosystem is of great practical significance for the formulation of policies for the development of agricultural ecological environment in the future and the realization of sustainable development of agricultural ecosystem.Taking 12 counties in Yulin city as the research unit,24 indexes are selected from agricultural environment subsystem,production input subsystem and social economy subsystem to construct the agricultural ecosystem vulnerability evaluation system.Combined with ArcGIS 10.2 and Grapher 12 software,the mathematical methods such as weighting method,entropy evaluation method and comprehensive index method are used to study the evolvement characteristics of the vulnerability types of agricultural ecosystem in Yulin city a from 2004 to2017 in three stages.Four representative starting points of 2004,2009,2014 and 2017 are selected as cross-section nodes.And the triangular diagram method is used to analyze the evolvement of the vulnerability types of agricultural ecosystem of 12 counties in Yulin city.The results showed the types of agricultural ecosystem vulnerability in Yulin city were divided into five types from 2004 to 2017:(1)Agricultural environment-Production inputSocial economy subsystem equilibrium vulnerability type(EPS type).(2)Agricultural environment-Social economy subsystem vulnerability type(PS type).(3)Agriculture environment-Production input-Social economy subsystem equilibrium vulnerability type to Production input-Social economy subsystem vulnerability type to Agriculture environment-Production input-Social economy subsystem equilibrium vulnerability type(EPS-type to PStype to EPS-type).(4)Agricultural environment-Production input-Social economy subsystem equilibrium vulnerability type to Production input-Social economy subsystem vulnerability type(EPS-type to PS-type).(5)Production input-Social economy subsystem vulnerability type to Agricultural environment-Production input-Social economy subsystem equilibrium vulnerability type(PS-type to EPS-type).The conclusion is as follows:Each subsystem vulnerability degree in various development stages show a distribution pattern:the southern areas are higher than the northern areas,and the 6 southern counties are higher than the 6 northern counties,which is basically the same as the actual development of the agricultural ecological environment in the region.However,the totally regional agriculture ecosystem vulnerability degree presents a trend of decrease year by year,which showes that with the continuous development of social economy,the investment in agricultural production and agricultural science and technology are increasing,the ability of regions to resist the vulnerability of agro-ecosystem is also improved.