洞庭湖区生态承载力系统耦合协调度时空分异

不同时空尺度下,生态承载力系统耦合协调度呈现不同差异和变化。在阐述耦合协调发展作用机理的基础上,构建了耦合协调度评价指标体系,利用容量耦合模型对洞庭湖区生态承载力系统耦合协调度进行时空分析。结果表明：① 时序变化上,2001~2012年洞庭湖区生态承载力系统耦合度和耦合协调度变化趋势基本趋同,大致呈现同步稳定上升态势,耦合度均值达0.499,处于拮抗阶段;耦合协调度均值达0.463,处于中度耦合协调阶段;年均增长率上,耦合度达3.35%,大于耦合协调度的3.05%。表明生态承载力内部系统耦合作用和协同效应明显,并且耦合作用的强度大于内部协调性。② 空间分异上,17个县域的耦合度出现了低水平耦合、拮抗阶段和磨合阶段3种状态,3种耦合状态的县域个数和区间变化呈现不同的差异。耦合协调度出现了低度耦合协调、中度耦合协调和高度耦合协调3种状态,其变化状况基本上与耦合度类似,但从协调状态的县域个数和区间变化来看,耦合协调度的变化稍滞后于耦合度的变化,空间分布与耦合度分布特征基本相似,高、低值区的空间分布由西南向东北大致呈现较低-高-低-高-较低的“M”型基本格局。③ 空间组合上,17个县域出现了低耦合低协调区、中耦合低协调区、中耦合中协调区、高耦合中协调区和高耦合高协调区5种空间组合类型,其基本空间格局是,低耦合低协调区集中分布在洞庭湖区中部和西南部,高耦合高协调区则沿京广线、石长线和常岳高速三线呈“三足鼎立”布局,其它不同组合类型则集中于高耦合高协调区外围呈“零星状”分布。

Spatio-temporal Difference of Coupling Coordinative Degree of Ecological Carrying Capacity in the Dongting Lake Region

Ecological carrying capacity is a complex dynamic system including natural-economy-society, and its intrinsic coordination is the key to sustainable carrying capacity of ecosystem. In different spatio-temporal scales, the coupling coordinative degree of ecological carrying capacity presents different differences and changes. On the basis of coupling coordinative development interactive mechanism of ecological carrying capacity, the article constructs an evaluation index system of coupling coordinative degree, and analyzes the temporal and spatial difference of coupling coordinative degree of ecological carrying capacity in the Dongting Lake region by using capacitive coupling model. The results show that: 1) The trends of coupling degree and coupling coordinative degree of ecological carrying capacity in the Dongting Lake region from 2001 to 2012 seemed to be the same, and presented roughly steady upward trend. The mean of coupling degree was 0.499, in antagonistic stage; the mean of coupling coordinative degree was 0.463, in the moderate coupling coordinative phase; the average annual growth rate of coupling degree was 3.35%, greater than coupling coordinative degree, which was 3.05%. It indicated that the internal coupling and synergies of the ecological carrying capacity was obvious, and the coupling strength was greater than the internal coordination. 2) As to spatial variation, there were three states of coupling degree in three different years in 17 counties of the Dongting Lake area, which were a low coupling, antagonistic phase and running-in phase, each coupling state had different county number and interval change. The coupling coordinative degree appeared three states of low coupling coordination, moderate coupling coordination and highly coupling coordination, the variation was substantially similar to the coupling degree, however the change of the county number and interval change in coordinative state laged behind the coupling degree. The spatial distribution of coupling coordinative degree and coupling degree were similar, high and low spatial differences were mainly decided by the historical development, social and economic developmental level, traffic location and natural resources. 3) As to spatial combination, there were five kinds of spatial combination types in three typical years in 17 counties of Dongting Lake area, which were low-low, medium-low, medium-medium,high-medium and high-high. The basic spatial pattern was that low-low type concentrates in the central and southwestern of Dongting Lake area, and high-high type were along the traffic lines of Beijing-Guangzhou, Shimen-Changde and Changde-Yueyang, and the layout looked like "three pillars". Other types were focused on periphery of the high-high type, in scattered distribution. The county changes of different combination types reflected the basic law of the change of coupling coordinative degree, which coupling degree and coupling coordinative degree were not consistent; in the process of human social and economic activities, the degree of utilization of resources and disturbance intensity of the ecological environment were directly driving forces leading to the change of coupling coordinative type.