Ren Zhengwei, Zhao Wei, Chen Ning, Zhou Xiaolong
College of Ecology, Lanzhou University, No. 222 Tianshui South Road, Lanzhou, 730000, Gansu, China.
College of Ecology and Environment, Key Laboratory of Oasis Ecology, Ministry of Education, Xinjiang University, Urumqi, Xinjiang, 830046, China.
NPJ Biodivers. 2024 Jul 25;3(1):17. doi: 10.1038/s44185-024-00049-3.
Two prevalent ecological mechanisms, niche dimensionality and light asymmetry, may well explain species loss with fertilization gradients in grassland communities. Although there is still controversy surrounding the two competitive mechanisms that maintain species coexistence, few studies have examined the patterns of change in dissimilarity in species composition (β-diversity) and the relative explanatory contributions of plant functional traits to α- and β-diversity when multiple resources are added. To clarify this knowledge gap, we conducted a 6-year experiment of resource addition in an alpine meadow on the Qinghai-Tibet Plateau to assess how species richness and spatial β-diversity are affected by increasing numbers of added resources (NAR) and light limitation. Our results found that both NAR and light limitation led to decreased species richness, suggesting that niche dimensionality and light asymmetry may contribute equally to species loss, rather than either alone. Moreover, NAR is the primary factor responsible for the increase in β-diversity, which exhibits a negative relationship with species richness. Furthermore, the increase in height is the most likely explanation for β-diversity, while the increase in SLA is the most likely explanation for species richness, thereby indicating the changes in species richness and composition can be effectively explained by the response of certain morphological functional traits with the addition of multiple resources. Future research should focus on the complex interactions of different ecological mechanisms that contribute to the maintenance of biodiversity in grassland ecosystems all over the world.
两种普遍存在的生态机制，生态位维度和光照不对称，很可能解释了草原群落中随着施肥梯度出现的物种丧失现象。尽管围绕维持物种共存的两种竞争机制仍存在争议，但很少有研究探讨当添加多种资源时物种组成差异（β多样性）的变化模式以及植物功能性状对α多样性和β多样性的相对解释贡献。为了填补这一知识空白，我们在青藏高原的一个高寒草甸上进行了为期6年的资源添加实验，以评估物种丰富度和空间β多样性如何受到添加资源数量增加（NAR）和光照限制的影响。我们的结果发现，NAR和光照限制均导致物种丰富度下降，这表明生态位维度和光照不对称可能对物种丧失的贡献相当，而非其中某一个单独起作用。此外，NAR是导致β多样性增加的主要因素，β多样性与物种丰富度呈负相关。再者，株高增加是β多样性增加的最可能解释，而比叶面积增加是物种丰富度增加的最可能解释，从而表明添加多种资源时某些形态功能性状的响应能够有效解释物种丰富度和组成的变化。未来的研究应聚焦于世界各地草原生态系统中有助于维持生物多样性的不同生态机制之间的复杂相互作用。
