珠三角城市群湿地景观格局变化及其驱动因素分析

Change of wetland landscape patterns and its driving factors in Pearl River Delta urban agglomeration

湿地生态系统是构建城市生态安全体系的重要组成部分。以珠江三角洲(简称珠三角)城市群湿地为研究对象,利用多时段遥感数据调查湿地资源时空分布,结合地理信息系统(GIS)技术分析湿地结构与景观格局变化,选取8个驱动因素进行主成分分析,探讨快速城市化背景下湿地景观格局动态变化的成因。结果表明:珠三角城市群湿地类型主要为水田,其次为水库坑塘与河渠,湖泊、滩地与沼泽地等分布面积相对较小;2000—2015年,湿地面积共损失了1613 km^(2),其中,2000—2005年损失最严重,之后面积损失趋势逐渐减缓,佛山市、广州市、中山市和惠州市湿地损失面积之和约占湿地总损失面积的77%;人类活动对湿地转移影响较大,主要表现为建设用地侵占湿地、水田转移为水库坑塘及滩地被开垦为水田;水田和河渠是优势景观类型,且聚集程度较高,其他类型的湿地空间分布趋于离散;人类活动是影响湿地景观格局变化的主要因素,城市扩张是侵占湿地的主要表现形式,此外,气候和政策等因素也对湿地景观变化产生一定影响。

Wetland ecosystem is an important part of urban ecological security system.Pearl River Delta(PRD)urban agglomeration was used as a research area,and the spatial and temporal distribution of wetland resources in the area was investigated using multi-period remote sensing data.At the same time,the changes of wetland structure and landscape pattern were analyzed combined with GIS technology,and eight driving factors were selected for principal component analysis to explore the causes of dynamic changes of wetland landscape in the background of rapid urbanization.The results showed that the main wetland types in PRD urban agglomeration were paddy fields,followed by reservoirs,ponds and canals,and the distribution area of lakes,beaches and marshes was relatively small.From 2000 to 2015,the wetland area of PRD urban agglomeration had been lost,with a total loss of 1613 km^(2),of which the most serious loss occurred during 2000-2005,and then the damage trend gradually slowed down;the sum of the wetland loss areas in Foshan,Guangzhou,Zhongshan and Huizhou accounted for about 77%of the total loss area.Through the study of the spatio-temporal conversion of wetlands,it was found that human activities had a far-reaching impact on wetland conversion in the past 15 years,mainly manifested in the occupation of wetlands in construction land,the transfer of paddy fields to reservoir/ponds,and the reclamation of beaches into paddy fields.The study of landscape index showed that paddy fields and canals were the dominant landscape types in PRD,with high degree of aggregation,while the spatial distribution of other wetland types tended to be discrete.It was found that human activities were the main factors affecting the wetland landscape pattern changes,and urban expansion was the main pathways of encroachment on wetlands.In addition,the wetland landscape was also influenced by the policies and climate.