Estimating the optimal vegetation coverage for the dominant tree and shrub species over China's northwest drylands  

作　　者：Zhongdian ZHANG Xiaoxu JIA Ping ZHU Mingbin HUANG Lidong REN Ming’an SHAO 

机构地区：[1]School of Geographic Sciences,Xinyang Normal University,Xinyang 464000,China [2]Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China [3]College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 100190,China [4]Yellow River Delta Modern Agricultural Engineering Laboratory,Chinese Academy of Sciences,Beijing 100101,China [5]State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Northwest A&F University,Yangling 712100,China

出　　处：《Science China Earth Sciences》2024年第5期1500-1517,共18页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.42022048&42107335);the Third Xinjiang Scientific Expedition of the Ministry of Science and Technology of the PRC(Grant No.2022xjkk0904);the project“CERN Long-term Observation Data Mining and Annual Data Report”(Grant No.KFJ-SW-YW043);the Xinyang Academy of Ecological Research Open Foundation(Grant No.2023XYQN12);the Nanhu Scholars Program for Young Scholars of XYNU。

摘　　要：Anthropogenic revegetation is an effective way to control soil erosion and restore degraded ecosystems in China's northwest drylands(NWD).However,excessive vegetation cover expansion has long been known to increase evapotranspiration,leading to reduced local water availability,which can in turn threaten the health and services of restored ecosystems.Determining the optimal vegetation coverage(OVC)is critical for balancing the trade-off between plant growth and water consumption in water-stressed areas,yet quantitative assessments over the entire NWD are still lacking.In this study,a modified Biome BioGeochemical Cycles(Biome-BGC)model was used to simulate the long-term(1961–2020)dynamics of actual evapotranspiration(ET_(a)),net primary productivity(NPP),and leaf area index(LAI)for the dominant non-native tree(R.pseudoacacia and P.sylvestris)and shrub(C.korshinkii and H.rhamnoides)species at 246 meteorological sites over NWD.The modified model incorporated the Richards equation to simulate transient unsaturated water flow in a multilayer soil module,and both soil and eco-physiological parameters required by the model were validated using field-observed ETadata for each species.Spatial distributions of OVC(given by the mean maximum LAI,LAI_(max))for the dominant species were determined within three hydrogeomorphic sub-areas(i.e.,the loess hilly-gully sub-area,the windy and sandy sub-area,and the desert sub-area).The modified Biome-BGC model performed well in terms of simulating ET_(a) dynamics for the four plant species.Spatial distributions of mean ET_a,NPP,and LAI_(max)generally exhibited patterns similar to mean annual precipitation(MAP).In the loess hilly-gully sub-area(MAP:210 to 710 mm),the OVC respectively ranged from 1.7 to 2.9 and 0.8 to 2.9 for R.pseudoacacia and H.rhamnoides.In the windy and sandy sub-area(MAP:135 to 500 mm),the OVC ranged from 0.3 to 3.3,0.5 to 2.6 and 0.6 to 2.1for P.sylvestris,C.korshinkii and H.rhamnoides,respectively.In the desert sub-area(MAP:90 to 500 mm),the OVC ranged from 0.4

关 键 词：Optimal vegetation coverage Water balance Leaf area index Biome-BGC model DRYLAND 

分 类 号：Q948.1[生物学—植物学]