基于GIS与RS技术的赤水河流域生态风险评价——以仁怀市为例

为揭示赤水河流域土地利用/覆被变化对区域生态风险的影响以及空间分布,以赤水河流域中游城市仁怀市作为研究区,采用GIS与RS技术与生态风险指数(ERI)模型,开展基于土地利用/覆被变化的生态风险评价研究,探讨了土地利用变化背景下仁怀市生态风险变化特征以及演变机理,并提出了政策保障措施。结果表明,(1)2000—2014年,区域内有林地、疏林地、水域、园地、建设用地面积增加,而耕地、灌木林地、草地面积减少;(2)仁怀市土地生态风险在空间上呈现较强的区域差异性,基本呈现由西南向东北转移的态势,中部地区生态风险高,建成区以及工业聚集区及其周边高,距离高生态风险区越远,生态风险等级越低;(3)整个研究区主要以中等及较高生态风险等级为主,2000年占整个研究区比例的50%以上,2014年达到65%以上。综上可知,仁怀市生态压力正在逐渐加大;政府在发展过程中应当避免由于高生态风险区域向外延伸,造成区域总体生态风险强度加大和面积增加。应当积极开展区域生态治理与恢复,强化土地利用科学规划。

Risk Assessment of the Aquatic Ecosystem of Chishui River Basin Using GIS and RS: Taking Renhuai City as an Example

Taking Renhuai City located at the middle reach of the Chishui River basin as an example,this paper investigated the impact of change inland use and cover on aquatic ecological system risk and its spatial distribution using GIS and RS method as well asthe ecological risk index (ERI) model.We assessed the evolution of the ecological risk and proposed mitigation methods to safeguard the ecological health of Renhuai city through land usage change.The main results are as follows.①During 2000-2014,the areas covered by forest,water,parks and construction increased,while the areas of arable crops,shrubs and grasslands decreased.② The ecological risk of the land in Renhuai City showed a strong regional variation increasing from the southwest to the northeast,with the ecological risk in the central,established residential and industrial areas higher than that in the surrounding areas.③The ecological risk in most of the studied area was moderate to high,accounting for more than 50％ and 65％ of the total areas in 2000 and 2014 respectively.In conclusion,the ecological pressure to Renhuai City has increased steadily over the past years,and it is hence important for policy makers to ensure that the ecological risk areas would not increase further.Future work should focus on improving ecological management and restoration,and rationalizing land utilization.