三峡库区生态系统时空分布及其演替特征

The Tempo-Spatial Distribution and Evolution of Ecosystem in the Three Gorges Reservoir Area

对三峡库区1990-2010年每隔五年陆地生态系统,建立了生态系统时空分布及演替的系统分析方法:在变化数量和结构上,对三峡库区5期生态系统空间分布变化以动态变化率、变化转移矩阵等方法进行统计分析;在空间分布上,利用八向空间共生矩阵、空间洛仑兹曲线与基尼系数、多尺度空间统计等方法,描述其空间分布格局及变化差异特性;基于景观生态学中的相邻矩阵和转移矩阵构建生态系统类型转换倾向性模型描述三峡库区生态系统演替特征。结果表明:森林和农田为主要优势的生态系统类型。1990-2010年水体与湿地、聚落和其他三种类型变化最剧烈。人类活动对各类型生态系统的作用范围要大于气候变化等自然条件的驱动作用,且作用强度呈现出随时间推移变化越来越小的特点。整个区域的生态系统类型转换与相关政策作用和水利工程建设直接相关。转换倾向性模型可以挖掘土地变化信息和驱动力作用。分析其演变的驱动力,可以加深对人类活动在地区变化中的作用和机制的认识,减少预测的不确定性。研究有助于了解三峡库区近20多年来土地利用的变化特征,从而为三峡库区环境保护、土地利用和土地规划的可持续发展提供参考价值。

Based on the spatial distribution dataset of the ecosystem types in the Three Gorges Reservoir area from 1990 to 2010, the systemic analysis methods were established to determine the spatiotemporal characteristics and variations of the ecosystem. The sampling time periods were 1990, 1995, 2000, 2005 and 2010. Several in-dexes describing the regional land use were investigated by different methods. For number and structure of the e-cosystem, the quantitative and structural statistical analysis methods, such as dynamic rate change and transfer matrix, were used. For layout of the ecosystem, the gray-level co-occurrence matrix, space Lorentz curve and the Gini coefficient, as well as multidimensional space statistics were applied. Combining with the land-use transition matrix, the adjacency matrix in landscape ecology was introduced into land-use change research, and the tenden-cy model of land-use type conversion was established to describe the succession characteristics of the ecological system. The results showed that the forest and farmland in the reservoir area were the predominant ecosystem types. Settlements, water-wetlands, and others were the environmental types with the largest transformation and dramatic change. The effects on various types of the ecosystem by human activities were larger than those by nat-ural driving forces such as climate changes, but the intensity of the anthropological influences exhibited a ten-dency decreasing with time. The ecosystem succession was closely related to the construction and management of the hydraulic water project. The land-use type conversion model developed in this study was showed to effectively explore the spatial patterns, the mechanisms, and the driven forces of the ecosystem changes. This knowledge can deepen our understanding on the roles and effects of human activities in the regional ecosystem changes, and reduce the uncertainty in forecasting the changes. The results provide a reference for sustainable development and environmental protection of land use and planning in the Three Gorges Reservoir area.