重庆市“一区两群”生境质量及其地形梯度分异

Habitat Quality and Terrain Gradient Differentiation of“One Urban Area and Two Town Groups”in Chongqing

开展生境质量时空演变定量化研究,对于生物多样性保护、生态系统服务功能维育、生态安全格局构建具有重要意义。该文以景观生态学理论为基础,利用InVEST模型对重庆市"一区两群"2000-2018年间生境质量进行定量化评价,并结合地形位指数和分布指数,探讨了生境质量时空变化规律的地形梯度效应。结果表明:(1)研究区主导景观类型为耕地,其次是林地,两者面积占比达80%以上;研究时段内,林地、建设用地、水域面积呈持续增加趋势,耕地、草地、未利用地连续减少。(2)研究区生境质量总体较优,但时段内略有下降;空间分布上,渝东南和渝东北生境质量相对较好,生境质量指数均值分别为0.792和0.723,都市区生境质量均值仅为0.614;空间变化方面,都市区生境质量呈持续退化趋势,渝东南生境质量持续变好,渝东北生境质量变化不明显。(3)研究区生境质量等级空间分布地形梯度效应显著,高生境质量分布与林地、草地景观在Ⅳ~Ⅴ级地形位呈主导优势,而低生境质量分布则与耕地、建设用地在Ⅰ~Ⅱ级地形位关联明显。(4)该研究成果可为重庆市国土空间差异化的生态环境保护政策制定提供重要参考。但就InVEST模型而言,针对地形复杂的山地丘陵区,差异化修正诸如阔叶林、针叶林、针阔混交林等同种类型不同种类生境敏感值和对生态威胁源的影响距离等参数仍需深入探讨。

It is of great significance to carry out quantitative research on spatial and temporal evolution of habitat quality for biodiversity conservation,ecosystem service function maintenance and ecological security pattern construction.Based on the theory of landscape ecology,this paper quantitatively evaluated the habitat quality of"One Urban Area and Two Town Groups"in Chongqing from 2000 to 2018 by the InVEST model,and discussed the terrain gradient effect of spatial and temporal variation of habitat quality by combining the topographic and distribution index.The results show that in study area,the dominating landscape is cultivated land,followed by woodland,which accounts for more than 80%of the total area.During the study period,the area of woodland,construction land,and wetland continue increased,while cultivated land,grassland and unused land declined continuously.The habitat quality was at a generally better level with slightly decreasing during the study period.In terms of spatial distribution,the habitat quality in southeast and northeast Chongqing is relatively good,with the average habitat quality index as 0.792 and 0.723,but only 0.614 in urban areas as a whole.In terms of spatial changes,the habitat quality in urban area kept continuously degrading,continuous improving in southeast Chongqing and slight changing in northeast Chongqing.The spatial distribution of habitat quality grades has a very significant terrain gradient effect.The high habitat quality distribution,woodland and grassland landscape play the leading roles at theⅣ~Ⅴterrain grades,while the low habitat quality distribution,cultivated land and construction land has a significant correlation at theⅠ~Ⅱterrain grades.The results of this study might provide important reference for the formulation of ecological environment protection policy of land and spatial differentiation in Chongqing.As far as the InVEST model is concerned,it is still necessary to study the parameters,such as the habitat sensitivity value and the influence distance to the ecological threat source of different species including broad-leaved forest,coniferous forest,coniferous-leaved mixed forest for the hilly and mountainous areas with complex topography.