1990-2017年喀斯特自然保护区土地利用变化对生境质量的影响

Land Use Change and Its Impact on Habitat Quality in Karst Nature Reserve from 1990 to 2017

[目的]探讨自然保护区生境质量变化规律及其影响因素,为制定有效的区域生态保护政策提供科学依据。[方法]基于Landsat系列影像数据,采用生境质量估算模型与土地利用转型生境贡献率,以贵州省兴义市坡岗自然保护区为例,分析土地利用变化对不同功能分区生境质量的影响并定量评估退耕还林还草政策情景对生境质量改善效果。[结果]1990—2017年自然保护区土地流转主要发生在草地和耕地转为林地、其他类型转为草地和林地间。28a保护区平均生境质量提高15.71%,且呈现先增加后减少的趋势。1990年保护区平均生境质量表现为:缓冲区>核心区>试验区,2001年以后转换为:核心区>缓冲区>试验区。在退耕还林还草政策情景下,坡岗自然保护区平均生境质量从当前情景的0.88提高到0.92,生境质量改善。[结论]坡岗自然保护区的建立、退耕还林还草工程的实施以及人类活动的增加是影响保护区生境质量变化的主要原因。

[Objective]The changes of habitat quality and its affecting factors in the nature reserve were studied for the formulation of effective local ecological protection policies.[Methods]Taking the Pogang nature reserve in Xingyi City of Guizhou Province as an example,based on the images of Landsat-5 TM,Landsat-7 ETM+,Landsat-8 OLI,and combining ArcGIS with ENVI software,we used habitat quality estimation model and habitat quality contribution rate of land use transformation to analyze the land use change and its impact on habitat quality from 1990 to 2017 and to quantitatively assess the effect of the policy of grain for green on the improvement of habitat quality.[Results]The land transformation of reserve mainly occurred from grassland and cultivated land to forest land,and from other land types to grassland and forest land from 1990 to 2017.During the past 28 years,the overall habitat quality of the reserve showed a trend of first increase and subsequent decrease.The increase was by 15.71%in comparison with the value in 1990.The average habitat quality of the reserve in 1990 was ranked as:buffer area>core area>pilot area;whereas the average habitat quality of the reserve after 2001 was the core area>buffer area>pilot area.As the policy of grain for green was carried out,the average habitat quality index of Pogang Nature Reserve increased significantly from 0.88 to 0.92.[Conclusion]The establishment of Pogang Nature Reserve,the implementation of the reforestation project and the increase of human activities are the main reasons for the change of the habitat quality.