21世纪以来典型喀斯特流域生态系统服务功能对土地利用变化的响应

Response of Ecosystem Service Function to Land Use Change in A Typical Karst Watershed since the 21st Century

为明晰喀斯特流域土地利用变化对生态系统服务功能的影响,本研究以贵州省典型喀斯特流域——南明河流域为例,基于3S技术,分析南明河流域2000—2020年土地利用的时空动态变化特征,采用InVEST模型并结合气象、土壤和地形等数据评估流域不同土地利用类型的水源涵养功能和碳储存功能,探讨流域20年时间序列下的生态系统服务功能的时空分异特征。结果表明,南明河流域平均水源涵养量和涵养能力分别为1.01×10^(6)m^(3)和44mm,整体呈下降—上升的变化趋势;空间布局上,水源涵养量与碳储量的高值区主要集中在林地、草地集中分布的东北部。21世纪以来,南明河流域土地利用变化特征表现为“两增三减”,其中,建筑用地的年变化速率最大可达13.07%。流域内林地水源涵养量占流域水源涵养总量的57.83%,碳储量占流域总碳储存量的60.09%,是流域最主要的碳库。上游地区大面积的林地和耕地向建筑用地转移,生态系统服务功能下降明显。本研究可为制定喀斯特地区流域生态恢复策略、促进土地可持续利用及提升生态系统服务功能提供科学依据与参考。

To clarify the impact of land use change on ecosystem service functions in karst watershed,this study took the typical karst watershed in Guizhou Province,Nanming River Watershed,as an example to analyze spatial and temporal dynamic changes of land use from 2000 to 2020 based on 3 S technology.By combining meteorological,soil and terrain data,InVEST model was used to evaluate the water conservation function and carbon storage function of different land use types and to assess the temporal and spatial differentiation characteristics of ecosystem services over a 20-year time series.The results showed that the average annual water conservation of Nanming River Watershed was 1.01×10^(6)m^(3)and the average water conservation capacity was 44 mm,showing a decreasing-rising trend,the high values of water content and carbon storage were mainly concentrated in the northeastern part where woodlands and grasslands were dense.Since the 21 st century,the land use change in Nanming River Watershed could be characterized as"two increases and three decreases",among which the maximum annual change rate of construction land reached 13.07%.The carbon storage of forest land in the watershed was the most important carbon bank of the watershed,accounting for 60.09%of the total carbon storage in the watershed,and the water content of forest land in the watershed accounted for 57.83%of the total water content of the watershed.A large area of forest land and cultivated land in the upstream area had been shifted to construction land,and the ecosystem service function declined significantly.This study provided a scientific basis and data reference for formulating ecological restoration strategies,promoting sustainable land use and improving ecosystem service functions in karst watersheds.