Large‐scale facilitative effects for a single nurse shrub: Impact of the rainfall gradient, plant community and distribution across a geographical barrier

作者：Nicolás Velasco, Cristina Soto‐Agurto, Lucas M. Carbone, Cesar Massi, Ramiro O. Bustamante, Christian Smit · 发表于：Journal of Ecology · 年份：2024 · DOI：10.1111/1365-2745.14247 · 被引用次数：12 · 研究领域：Ecology and Vegetation Dynamics Studies、Plant and animal studies、Species Distribution and Climate Change

Abstract Importance of nurse plants structuring plant communities is well‐appreciated at local scales, yet the effect of a single nurse on large scales has been neglected in analyses. So far, studies only use environmental gradients within one type of ecosystem and tend to generalize the nurse effects. To assess how the effect of a single nurse species is modulated by different environmental settings, interactions between the shrub Vachellia caven and the surrounding plant communities were evaluated at 481 paired plots (outside vs. underneath the plant crown), in 39 sites across two distribution ranges, the Mediterranean west and the mostly subtropical east of the Andes Mountains (covering ca. 2 × 10 6 km 2 ). Cover, abundance and richness of perennial plants underneath and outside V. caven were used as response variables to estimate an index indicative of plant interactions (relative interaction index [RII]) and tested how this was affected by the rainfall gradient and distribution range. Overall, RII responses to rainfall gradients had low conditional R 2 (~0.25) in this large scale of analysis, but were significantly different between ranges: the RII followed a quadratic trend across the rainfall gradient in the western range, while this relationship was positive and close to linear at the eastern range. Then, by projecting the RII models (i.e. for abundance, cover and richness) spatially through a consensus map, we show that most positive effects of V. caven are geographi...