流域土地利用与景观生态风险响应关系研究

Correlational relationship between land use and landscape ecological risks in Inner Mongolia section of middle Nenjiang River

以嫩江中游内蒙古段为例,深入分析流域2000~2020年土地利用格局时空演替特征,构建流域景观生态风险评价模型,识别20a间流域景观生态风险时空变化特征,揭示流域土地利用格局与景观生态风险响应关系.结果表明:嫩江中游内蒙古段土地利用类型以有林地为主,20a间土地利用格局总体转变不大,但天然有林地下降、湿地萎缩明显,旱地减少、水田增加,人工水库坑塘增加显著,流域景观生态风险高值区主要集中在绰尔河和罕达罕河下游,20a间景观生态向高风险转化最为显著的类型为水库坑塘,由2000年的8.90%上升为2020年的53.99%,景观生态高风险区面积占比最高的为水田,其次为旱地、城镇用地、农村居民点和其他建筑用地,景观聚集的态势变化较小,同时也表现出高风险集聚区增加和低风险集聚区减少的趋势,景观生态风险高-高集聚区中面积占比最高的土地利用类型为水田,占整个集聚区面积的33.26%,流域中水田、水库坑塘等人工土地利用类型不仅从景观生态风险等级还是集聚性上均高于其他土地利用类型.本研究不仅揭示了流域20a间土地开发利用格局特征,同时识别出对于增加流域景观生态风险的土地利用类型,为流域后续产业结构调整、深化生态环境保护提供有力支撑.

Inner Mongolia section in the middle reaches of Nenjiang River was an important part of the ecological security barrier in the north of China and played an important role in maintaining the ecological security in the middle and lower reaches of the river basin.This paper analyzed the spatial and temporal succession characteristics of land use pattern in watershed from 2000 to 2020,as well as the landscape ecological risk assessment model had been built.Based on the spatial and temporal succession of landscape ecological risk in the river basin over the past 20 years,the relationship between land use pattern and landscape ecological risk had been revealed.The results showed that in the past 20 years,the land use type in Inner Mongolia in the middle reaches of Nenjiang River was mainly forest land,and the overall pattern of land use had not changed much.However,the area of natural forests,wetlands and dryland had decreased significantly,and the area of paddy fields and artificial reservoirs had increased markedly.The landscape ecological risk area of the basin was mainly concentrated in the lower reaches of the Choer River and the Handahan River.In the last 20 years,the artificial reservoirs were the most obvious type of ecological transition to high risk,which increased from 8.90%in 2000 to 53.99%in 2020.The highest proportion of landscape ecological high risk area was paddy field,followed by dry land,urban land,rural residential area and other building land.Although with little change in global aggregation trends,there was a trend of increasing high-risk agglomerations and decreasing low-risk clusters in local aggregation trends.The land use type with the highest proportion of landscape ecological risk high-high agglomeration area was paddy field,accounting for 33.26%of the whole agglomeration area.Artificial land use types such as paddy fields and artificial reservoir were not only higher than other land use types in landscape ecological risk level,but also higher in agglomeration.This study provided strong support for the structural adjustment of subsequent industries in the river basin and the deepening of ecological protection.