Estación Experimental de Zonas Áridas, Consejo Superior de Investigaciones Científicas, EEZA-CSIC, Carretera de Sacramento s/n, La Cañada de San Urbano, 04120, Almería, Spain.
University of Bordeaux, UMR CNRS 5805 EPOC, 33405, Talence, France.
New Phytol. 2014 Apr;202(1):95-105. doi: 10.1111/nph.12641. Epub 2013 Dec 12.
Facilitative interactions are defined as positive effects of one species on another, but bidirectional feedbacks may be positive, neutral, or negative. Understanding the bidirectional nature of these interactions is a fundamental prerequisite for the assessment of the potential evolutionary consequences of facilitation. In a global study combining observational and experimental approaches, we quantified the impact of the cover and richness of species associated with alpine cushion plants on reproductive traits of the benefactor cushions. We found a decline in cushion seed production with increasing cover of cushion-associated species, indicating that being a benefactor came at an overall cost. The effect of cushion-associated species was negative for flower density and seed set of cushions, but not for fruit set and seed quality. Richness of cushion-associated species had positive effects on seed density and modulated the effects of their abundance on flower density and fruit set, indicating that the costs and benefits of harboring associated species depend on the composition of the plant assemblage. Our study demonstrates 'parasitic' interactions among plants over a wide range of species and environments in alpine systems, and we consider their implications for the possible selective effects of interactions between benefactor and beneficiary species.
促进相互作用被定义为一个物种对另一个物种的积极影响，但双向反馈可能是积极的、中性的或消极的。理解这些相互作用的双向性质是评估促进作用潜在进化后果的基本前提。在一项结合了观察和实验方法的全球研究中，我们量化了与高山垫状植物相关的物种的盖度和丰富度对受益垫状植物繁殖特征的影响。我们发现，随着与垫状植物相关的物种盖度的增加，垫状植物种子的产量下降，这表明作为一个受益者总体上是有代价的。垫状植物相关物种对垫状植物的花密度和结实率有负面影响，但对结实率和种子质量没有影响。垫状植物相关物种的丰富度对种子密度有积极影响，并调节了它们丰度对花密度和结实率的影响，这表明承载相关物种的成本和收益取决于植物组合的组成。我们的研究表明，在高山系统中，植物之间存在着广泛的物种和环境范围内的“寄生”相互作用，我们考虑了它们对受益种和受益种之间相互作用可能产生的选择影响的意义。
