摘要
干旱区生态系统的水文连通性影响植被斑块形态的空间分异。植被形态对水文连通性的适应是一个复杂且长期的过程。研究植被与水文连通性,过去多基于群落以上尺度,不涉及微观尺度。从植株个体角度探讨植被斑块形态与水文连通性关系,有助于挖掘微观尺度上景观格局对生态过程的驱动机制。本研究以黄土高原丘陵沟壑区多年生灌丛作为研究对象,以高分辨率无人机航拍照片解译和野外定点观测为研究手段,量化植被斑块形态与水文连通性之间定量关系,分析二者对泥沙截留与土壤固碳等关键生态过程的影响。结果表明:(1)坡面灌丛斑块总体呈现横向生长趋势,灌丛斑块纵横比小于1;灌丛斑块纵横比从坡顶到坡底逐渐增大,分别为0.64、0.70、0.79、0.83;(2)灌丛方向与水流方向夹角从坡顶到坡底先减小再增大;坡面中部的坡度最大,灌丛方向最接近与水流垂直的方向;(3)灌丛的汇流累积量从坡顶到坡底逐渐增大,表明其水文连通度逐渐增大;水文连通度与灌丛斑块纵横比呈正相关关系;当水文连通度足够大时,灌丛在横纵方向上的生长没有倾向,形状近似为圆形;(4)泥沙拦截量和固碳效率随坡位下降而下降,二次曲线拟合表明泥沙拦截量和固碳效率随水文连通度增加呈增加态势,表明水文连通度有促使植株自主优化株型、提升泥沙截留和固碳效率的功效。本研究有助于为黄土高原干旱区植被结构优化及生态建设提供案例分析与借鉴。
The hydrological connectivity of ecosystems in arid areas affects the spatial differentiation of vegetation patch morphology.It is a complex and long-term process for the adaptation of vegetation morphology to hydrological connectivity.Previous research on the correlation between vegetation and hydrological connectivity was conducted on a larger scale of above community scale,not on the microscale.Investigation into the relations of vegetation patch and hydrological connectivity at single-plant scale is expected to be conducive to the revealing of the driving mechanisms of landscape patterns on ecological processes.In this study,by application of interpolation of high-resolution photograph by drone and field survey,perennial shrubs in the hilly and gully region of the Loess Plateau was focused to interpret the correlations between vegetation patch morphologies and hydrological connectivity.Besides,their implications on sediment retention and soil carbon sequestration were also investigated.We have the following findings.(1)The shrub patches generally exhibited a vertical growth tendency,with a horizontal/vertical ratio of less than 1.The horizontal/vertical ratio of the shrub patches increased from the top of slope crests to bottoms,as 0.64,0.70,0.79,0.83.(2)The intersection angle between the direction of shrub patches and the water flow showed a decreasing-then-increasing trend from slope crest to its bottom.Notably,in the middle slope it exhibited the highest slope corresponding to the nearest-to-vertical intersection angle between the direction of shrub patches and water flow.(3)The accumulation of flows increased from slope crests to bottoms,indicating a rising trend in hydrological connectivity.The horizontal/vertical ratios of shrub patches exhibited a positive correlation with hydrological connectivity.When hydrological connectivity reached a high level,the horizontal/vertical ratio approached 1,indicating a close-to-circular shape of the shrub patches.(4)Finally,the sediment retention and carbon sequestration rate decreased along with the slope position decrease.By quadratic curve fitting analysis it is found that the sediment retention and carbon sequestration rate increased along with the increased hydrological connectivity,which implies that hydrological connectivity drives the self-optimization of plant morphologies and further improves the effectiveness of soil carbon sequestration and sediment retention.This research provides references for vegetation structure optimization and ecological renovation in arid area of the Loess Plateau.
作者
苏常红
刘宇
宋子豪
寻雅雯
SU Changhong;LIU Yu;SONG Zihao;XUN Yawen(College of Geographic and Environmental Sciences,Tianjin Normal University,Tianjin 300387,China;Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China)
出处
《山地学报》
CSCD
北大核心
2023年第3期375-385,共11页
Mountain Research
基金
国家自然科学基金(42271302,42071239)。
关键词
水文连通性
灌丛
泥沙截留
土壤固碳
黄土高原
hydrological connectivity
shrub morphology
sediment retention
soil carbon sequestration
the Loess Plateau
