濒危植物裸果木群落物种多样性与土壤因子的关系

Species diversity of the endangered plant Gymnocar⁃pos przewalskii community and its correlationwith soil characteristics

摘要:

【目的】 探究裸果木（Gymnocarpos przewalskii）群落物种多样性特征及其与土壤因子的相关关系。【方法】 对祁连山西端不同生境裸果木群落进行植被调查，并分析裸果木群落物种组成、多样性特征及与土壤因子的相关性。【结果】 裸果木群落植物共有25 种，隶属22 属12 科，主要为菊科（6 种）、藜科（6 种）和禾本科（3 种），且以半灌木和多年生草本为主；裸果木群落生境土壤含水量较少（2. 64%），呈强碱性（pH 值为8. 99，全盐量为2. 75 g/kg）；土壤养分含量较低（有机碳、全氮、全磷含量均值分别为1. 34、0. 15、0. 29 g/kg，速效氮、速效磷和速效钾含量分别为13. 67、3. 54、70. 03 mg/kg），且在不同生境差异显著（P＜0. 05）；裸果木群落物种多样性指数较低，Pielou 均匀度指数与含水率呈极显著正相关（P＜0. 01），与速效氮呈显著正相关（P＜0. 05）。【结论】 祁连山西端裸果木群落物种多样性水平较低，群落结构简单，土壤水分条件差、养分贫瘠，土壤含水率、速效氮对群落Pielou 均匀度指数有显著影响。

Abstract:

【Objective】 To explore the species diversity of the Gymnocarpos przewalskii community and its relationshipwith soil factors，providing a scientificbasisfor the protection of endangered plant G. przewalskii community.【Method】 Field investigationswere conducted on the G. Przewalskii community atthe western end of the QilianMountains. Species composition，species diversity，and the correlation between species diversity and soilfactors wereanalyzed.【Result】 G. przewalskii communityhas a simple composition structureand low species diversity，with a totalof 25 species，22 genera and 12 families recorded. Mostspecies are sub ‐shrubs and perennial herbs fromfamilies Asteraceae（6 species），Chenopodiaceae（ 6 species） and Poaceae（ 3 species）. The soil in thiscommunity was low in nutrients（2. 64%） andstrongly alkaline （pH=8. 99，total salt=2. 75 g/kg）. The average contents of organic carbon，total nitrogen and total phosphorus were 1. 34，0. 15 and 0. 29 g/kg，respectively. The average contents of availablenitrogen，available phosphorus and available potassium were 13. 67，3. 54 and 70. 03 mg/kg，respectively. Significantdifferences in soil nutrient contentswere observed among different G. przewalskii communities （P＜0. 05）. The Pielouindexof the G. Przewalskii community was significantly positively correlated with soil content and available nitrogen.【Conclusion】 The plantdiversity levelof G. przewalskii communityatthe western end of Qilian Mountain islow，and the community structure issimple. The soil water and nutrient conditionsare poor，and the Pielouindexis significantlypositively correlated with soil water content and available nitrogen.