基于地理探测器的喀斯特植被NPP定量归因

Quantitative Attribution Analysis of NPP in Karst Peak Cluster Depression Based on Geographical Detector

植被净第一性生产力(NPP)作为生态系统功能的重要指标,既可以反映植被的生长状况,又是生物圈内碳循环的重要分量。喀斯特地区植被NPP的研究是植被建设和生态系统恢复的重要基础,其影响因素的定量识别对喀斯特地区的生态恢复与区域可持续发展具有重要意义。在高精度NDVI数据反演的基础上,运用CASA模型模拟贵州省典型峰丛洼地区三岔河流域2015年区域尺度的植被NPP,分析喀斯特地区植被NPP的空间变化特征,综合海拔、坡度、降水、温度、植被覆盖度和土地利用类型等影响因子,应用地理探测器方法在不同地貌形态类型区内进行喀斯特植被NPP空间异质性的定量归因研究。结果表明:植被覆盖度与温度是植被NPP的显著控制因子,其交互作用对NPP的解释力为77.8%;地貌形态类型对植被NPP的空间分布具有宏观控制作用,土地利用类型在相对平缓的平原、台地地区对NPP的解释力是山地丘陵等地势起伏较大地区解释力的近两倍;海拔因子在小起伏中山和中起伏中山等山地地区对NPP的解释力强于较平缓地区;各个地貌形态类型区内因子的层间差异均随地貌特征的变化而显现出不同程度的差异性。双因子的交互作用均能增强对植被NPP空间分布的解释力,且在各个地貌形态类型区中,解释力排在前三位的主导交互作用方式均为植被覆盖度因子与另一影响因子的叠加。因此,在喀斯特地区未来的发展过程中,应考虑多种环境因子之间的交互作用,从多视角、多维度探究环境因子对植被NPP的影响,为喀斯特石漠化的治理工作提供参考依据。

As the basis of ecosystem function,net primary productivity(NPP)can not only reflect the growth of vegetation,but also is an important component of carbon cycle in biosphere.The study of NPP in karst areas is an important basis for vegetation construction and ecosystem restoration.The quantitative identification of its influencing factors is of great significance for ecological restoration and regional sustainable development in karst areas.Based on the effective interpretation of high-resolution NDVI data,this paper uses CASA model to simulate the NPP of Sancha River basin in the typical peak cluster depression of Guizhou Province in 2015.The quantitative attribution of NPP spatial heterogeneity of karst vegetation in different geomorphological types is studied by using geographical detector method.Elevation,slope,precipitation,temperature,vegetation coverage and land use type were considered as the influencing factors.The results show that vegetation coverage and temperature are the significant controlling factors of NPP,and their interactive explanatory power to NPP is 77.8%.Geomorphology have macro-control effect on the spatial distribution of NPP.The explanatory power of land use types to NPP in relatively flat plain and terrace areas is nearly twice as strong as that in mountain and hilly areas.The explanatory power of NPP in mountain areas such as small relief mountain and middle relief mountain is stronger than that in gentle areas,and the interlayer differences of factors in different geomorphological types show varying degrees with the changes of geomorphological characteristics.The interaction of two factors can enhance the explanatory power of NPP spatial distribution.Among the geomorphological types,the dominant interaction mode of explanatory power in the top three is the superposition of vegetation coverage factor and another influencing factor.Therefore,in the future development process of karst area,the interaction between various environmental factors should be considered,and the impact of environmental factors on NPP should be explored from multiple perspectives and dimensions in order to provide reference for the control of karst rocky desertification.