Plant–plant interactions as a mechanism structuring plant diversity in a Mediterranean semi-arid ecosystem

Plant–plant interactions are among the fundamental processes that shape structure and functioning of arid and semi-arid plant communities. Despite the large amount of studies that have assessed the relationship between plant–plant interactions (i.e., facilitation and competition) and diversity, often researchers forget a third kind of interaction, known as allelopathy. We examined the effect of plant–plant interactions of three dominant species: the perennial grass Lygeum spartum, the allelopathic dwarf shrub Artemisia herba-alba, and the nurse shrub Salsola vermiculata, on plant diversity and species composition in a semi-arid ecosystem in NE Spain. Specifically, we quantified the interaction outcome (IO) based on species co-occurrence, we analyzed diversity by calculation of the individual species–area relationship (ISAR), and compositional changes by calculation of the Chao-Jaccard similarity index. We found that S. vermiculata had more positive IO values than L. spartum, and A. herb...

植物间相互作用是塑造干旱与半干旱植物群落结构与功能的核心过程之一。尽管已有大量研究探讨了植物间相互作用（即促进作用与竞争作用）与物种多样性之间的关联，但研究者往往忽略了第三种相互作用类型——化感作用（allelopathy）。本研究以西班牙东北部的半干旱生态系统为研究对象，评估了3个优势物种的植物间相互作用对植物多样性及物种组成的影响，这3个物种分别为多年生草本Lygeum spartum、具化感作用的矮灌丛Artemisia herba-alba以及保育灌丛Salsola vermiculata。具体而言，本研究基于物种共存情况量化了相互作用结果（interaction outcome, IO），通过计算单个物种-面积关系（individual species–area relationship, ISAR）分析物种多样性，并通过计算蔡-雅卡德相似性指数（Chao-Jaccard similarity index）分析物种组成变化。研究发现，Salsola vermiculata的相互作用结果值较Lygeum spartum更为正向，而Artemisia herba-alba的……