金沙江干热河谷不同植被类型植物叶片碳氮磷生态化学计量特征

Ecological stoichiometry of leaf C,N and P of different vegetation types in the Dry-Hot Valley of the Jinsha River

【目的】金沙江干热河谷生态环境恶劣,植被生长发育差,探明该区域内天然林、人工林和稀树灌草丛植物叶片C、N、P元素生态化学计量特征,对金沙江干热河谷植被恢复及生态治理效益评价具有重要意义。【方法】2021年1月对金沙江干热河谷上、中、下游共47个样地进行野外调查、样品采集及室内分析,对比研究金沙江干热河谷天然林、人工林和稀树灌草丛植物叶片的C、N、P生态化学计量特征及其影响因素。【结果】1)金沙江干热河谷天然林、人工林和稀树灌草丛植物叶片C、N、P元素含量受土壤等环境因子影响,植物叶片C、N、P元素含量均表现为天然林>人工林>稀树灌草丛。2)植物叶片C/N、C/P表现为稀树灌草丛>人工林>天然林,植物叶片N/P表现为天然林>人工林>稀树灌草丛。3)金沙江干热河谷天然林、人工林和稀树灌草丛植被生长发育均受N、P元素限制,其中稀树灌草丛受N、P元素限制最大,天然林受N、P元素限制最小。【结论】金沙江干热河谷天然林、人工林和稀树灌草丛植物C、N、P元素含量均受土壤等环境因子影响,其中稀树灌草丛植被-土壤C、N、P元素含量最低,植被生长发育受N、P元素限制最大,人工林植被-土壤C、N、P元素含量有效提高,植被生长发育受N、P元素限制逐渐减小。人工造林在金沙江干热河谷植被恢复及生态环境治理中取得了不错的成果,通过提高土壤水分、土壤营养元素含量等条件可以有效改善植被恢复及生态治理效应。

【Objective】The Dry-Hot Valley of the Jinsha River has a poor ecological environment and poor vegetation growth and development.It is of great significance to explore the ecological stoichiometric characteristics of C,N and P elements in the leaves of natural forests,artificial forests and savannahs in this region for the evaluation of vegetation restoration and ecological management benefits of the Dry-Hot Valley of the Jinsha River.【Method】In January 2021,a total of 47 plots in the upper,middle and lower reaches of the Dry-Hot Valley of the Jinsha River were investigated in the field,and the samples were collected and analyzed in the laboratory.The C,N and P ecological stoichiometric characteristics and influencing factors of the leaves of natural forests,artificial forests and savannahs in the Dry-Hot Valley of the Jinsha River were compared.【Result】(1)The contents of C,N and P elements in the leaves of natural forests,artificial forests and savannahs in the Dry-Hot Valley of Jinsha River were affected by soil and other environmental factors,and the contents of C,N and P elements in the leaves of plants were as follows:natural forests>artificial forests>savannahs.(2)The ratios of C/N and C/P in leaves were as follows:savannahs>artificial forests>natural forests,and the ratio of N/P in leaves was as follows:natural forests>artificial forests>savannahs.(3)The growth and development of natural forests,artificial forests and savannahs in the Dry-Hot Valley of the Jinsha River were all restricted by N and P elements,among which savannahs were the most restricted by N and P elements,while natural forests were the least restricted by N and P elements.【Conclusion】This study shows that the contents of C,N and P elements in natural forests,artificial forests and savannahs in the Dry-Hot Valley of the Jinsha River are influenced by environmental factors such as soil.Among them,the contents of C,N and P elements in the vegetation and soil of savannahs were the lowest,and the growth and development of vegetation were the most restricted by N and P elements.The contents of C,N and P elements in the vegetation and soil of artificial forests are effectively increased,and the growth and development of vegetation are gradually reduced by N and P elements.These results indicate that artificial afforestation has achieved good results in vegetation restoration and ecological environmental governance in the Dry-Hot Valley of the Jinsha River,and it can effectively improve vegetation restoration and ecological governance effects by increasing soil moisture and soil nutrient content.