Is a restricted niche the explanation for species vulnerability? Insights from a large field survey of Astragalus tragacantha L. (Fabaceae)

In this study, we examine the realized niche of A. tragacantha in Provence. We focus our fieldwork on habitat characteristics, floristic survey and perform an exhaustive demographic census. We base our analyses on total density and densities of different size stages of A. tragacantha. We delineate its realized ecological niche with the Outlying Mean Index (OMI) multivariate method and estimated the effects of environmental gradients on A. tragacantha populations with the Generalized Joint Attribute Modelling method (GJAM). Analyses based on occurrence data did not support the hypothesis that a too narrow niche by itself explains the vulnerability of A. tragacantha. However, niche modelling revealed differences among size stages supporting a restricted regeneration niche and a wider ecological range in the past.

This dataset is accompanying the manuscript published in Flora \"Is a restricted niche the explanation for species vulnerability? Insights from a large field survey of Astragal...

本研究针对普罗旺斯地区的A. tragacantha（学名：Astragalus tragacantha，黄芪属物种），探究其实际生态位（realized niche）。本次研究的野外工作涵盖生境特征调查、植物区系调研，并完成了全面的种群统计普查。本分析以A. tragacantha的总种群密度，以及其不同大小级别的种群密度作为分析依据。本研究采用离群均值指数（Outlying Mean Index，OMI）多元分析方法，划定该物种的实际生态位；并借助广义联合属性建模方法（Generalized Joint Attribute Modelling，GJAM），评估环境梯度对A. tragacantha种群的影响。基于物种出现记录数据的分析结果，并不支持“过窄的实际生态位本身即可解释A. tragacantha的生存脆弱性”这一假说。但生态位建模结果显示，不同大小级别的种群存在显著差异，这表明该物种的更新生态位较为狭窄，而历史上其生态幅曾更为宽广。

本数据集配套发表于期刊《Flora》的研究论文，论文标题为《受限生态位能否解释物种脆弱性？基于黄芪属大范围野外调查的研究启示》，英文原文标题为"Is a restricted niche the explanation for species vulnerability? Insights from a large field survey of Astragal..."。