景观格局动态对浑善达克沙地植物物种多样性和功能多样性的影响

Effects of landscape pattern dynamics on plant species and functional diversity in Hunshandak Sandland

景观格局是影响植物物种多样性(PSD)和功能多样性(PFD)变化的重要驱动因素。然而,目前对景观格局动态的作用机制仍然不清楚。浑善达克沙地固定沙丘、半固定沙丘、流动沙丘、丘间低地、湖泊和建设用地镶嵌分布,形成了复杂的景观格局,是揭示这种机制的理想地区。本文对该地区2008–2017年的遥感图像进行处理,对PSD和PFD进行实地调查和分析,采用Spearman相关性分析和广义线性混合模型识别了对PSD和PFD有显著贡献的景观格局指数;采用结构方程模型解析了景观格局动态变化对PSD和PFD的直接和间接效应。结果表明,PSD和PFD均受2–4年前景观格局的影响。PSD主要受形状指数、面积和边缘指数以及聚集指数的重要影响,PFD主要受形状指数和聚集指数的影响。由于环境过滤和扩散限制,欧氏邻近距离指数和分离度指数是描述PFD的良好指标。综上,在世界干旱和半干旱地区土地的景观规划、管理和生物多样性保护过程中,必须考虑景观的动态和演变。

Aims:Landscape pattern is an important driving factor that influences changes in plant species diversity(PSD)and plant functional diversity(PFD).The Hunshandak Sandland,a region in Inner Mongolia,is characterized by a variety of sand dunes,lakes,and built-up areas to form a complex and evolving landscape,which presents an ideal area to elucidate these mechanisms.Methods:In this study,we processed remote-sensing images from 2008–2017 from the study area and conducted field surveys and analysis to investigate PSD and PFD.Spearman correlation analysis and general linear mixed model were employed to identify landscape pattern indices that significantly contributed to PSD and PFD.Furthermore,a structural equation model was utilized to determine both the direct and the indirect effects of dynamic changes in the landscape pattern on PSD and PFD.Results:The results indicated that both PSD and PFD were influenced by landscape patterns from the previous 2–4 years.We discovered that PSD was primarily influenced by shape index,area and edge index,and aggregation index and were relevant in different timescales and land use types.PFD was predominantly affected by shape index and aggregation index.Conclusion:The dynamics of landscape pattern must be considered in the process of landscape planning,management,and conservation of biodiversity in arid and semi-arid lands in Inner Mongolia and could be translated to similar regions worldwide.