河西走廊中段荒漠草地地上生物量分布特征及其与环境因子的关系

Aboveground Biomass Distribution of Desert Grasslands and Its Responses to Environmental Factors in Middle Regions of Hexi Corridors

[目的] 揭示河西走廊中段荒漠草地地上生物量的空间分布特征及其与环境因子的关系，为区域草地生态系统碳库及其变化评估提供基础资料。[方法] 利用从52个样点获得的样方调查数据，进行统计分析。[结果]（1）河西走廊中段荒漠草地单位面积地上生物量的范围为11.17~523.76 g/m2，平均值为149.67 g/m2，大致表现为西北高，东南低的分布特征；（2）调查中共出现15种优势植物群落地，地上部生物量黑果枸杞群落最小，为49.887.42 g/m2，叉枝鸦葱群落最大，为201.6998.48 g/m2；（3）地上生物量与经度呈显著的负相关关系，与海拔呈显著的正相关关系；（4）土壤环境因子能够解释地上生物量39.8%的空间变异，其中土壤类型、土壤容重和土壤有机质的影响较显著，而土壤含水量的影响相对较弱。[结论] 河西走廊荒漠草地地上生物量趋势为由西北至东南逐渐降低；海拔和土壤环境因子是影响分布格局的关键因子。

[Objective] Spatial distribution of aboveground biomass and its relationship with environmental factors were studied in desert grassland in the middle part of Hexi Corridor to provide a reliable data for the assessment of grassland ecosystem carbon stock, and to illustrate its change at regional scale. [Methods] The present study, based on a total of 52 sampling sites in desert grasslands in the middle region of Hexi Corridors, illustrated the regional distribution pattern of aboveground biomass and its response to environmental factors were investigated. [Results] The results showed that aboveground biomass of desert grasslands ranged from 11.17~523.76 g/m2, with an average of 149.67 g/m2, and increased from the southeast to the northwest in the survey area. There were 15 communities with dominant species appeared in these 52 sampling. Average aboveground biomasses of Lycium ruthenicum and Scorzonera divaricate community were 49.887.42 g/m2 and 201.6998.48 g/m2, respectively, which were also the minimum and maximum of aboveground biomass among the 15 communities. Aboveground biomass was significantly and negatively correlated with longitude, and was significantly and positively correlated with elevation. 39.8% of the spatial variation of aboveground biomass can be interpreted by soil factors. Among which, soil type, soil bulk density and soil organic matter were significantly affected aboveground biomass distribution of desert grassland, while the effects of soil moisture on aboveground biomass was weak. [Conclusion] Aboveground biomass in desert grassland of Hexi Corridor increased from the southeast to the northwest. Altitude and soil environmental factors are the key factors affecting the distribution pattern.