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14 páginas.- 6 figuras.- 1 tabla.- referencias.- Additional supporting information may be found in the online version of the article at the publisher’s website, Although plant–plant interactions (i.e. competition and facilitation) have long been recognised as key drivers of plant community composition and dynamics, their global patterns and relationships with climate have remained unclear. Here, we assembled a global database of 10,502 pairs of empirical data from the literature to address the patterns of and climatic effects on the net outcome of plant interactions in natural communities. We found that plant interactions varied among plant performance indicators, interaction types and biomes, yet competition occurred more frequently than facilitation in plant communities worldwide. Unexpectedly, plant interactions showed weak latitudinal pattern and were weakly related to climate. Our study provides a global comprehensive overview of plant interactions, highlighting competition as a fundamental mechanism structuring plant communities worldwide. We suggest that further investigations should focus more on local factors (e.g. microclimate, soil and disturbance) than on macroclimate to identify key environmental determinants of interactions in plant communities., This work was supported by the National Natural Science Foundation of China (32071524, 31770514 and 31870711). International research travel by J.H.C.C. was partly funded by the Royal Netherlands Academy of Arts and Sciences (KNAW, CEP grant 12CDP007).

Similarity among species in traits related to ecological interactions is frequently associated with common ancestry. Thus, closely related species usually interact with ecologically similar partners, which can be reinforced by diverse co-evolutionary processes. The effect of habitat fragmentation on the phylogenetic signal in interspecific interactions and correspondence between plant and animal phylogenies is, however, unknown. Here, we address to what extent phylogenetic signal and co-phylogenetic congruence of plant-animal interactions depend on habitat size and isolation by analysing the phylogenetic structure of 12 pollination webs from isolated Pampean hills. Phylogenetic signal in interspecific interactions differed among webs, being stronger for flower-visiting insects than plants. Phylogenetic signal and overall co-phylogenetic congruence increased independently with hill size and isolation. We propose that habitat fragmentation would erode the phylogenetic structure of interaction webs. A decrease in phylogenetic signal and co-phylogenetic correspondence in plant-pollinator interactions could be associated with less reliable mutualism and erratic co-evolutionary change. Copyright, This study was funded in part by the National Institute of Agricultural Technology (INTA), Balcarce (PNECO1302), the Argentina National Research Council for Research (CONICET) (PIP 01623), the National Fund for Research (PICT 01300), the National University of Comahue (B152/04) and the European Research Council (through an Advanced Grant to JB). M.A.A., G.G. and M.S. are career researchers of CONICET.

8 páginas, 2 figuras, 2 tablas., With the advent of molecular phylogenies the assessment of community assembly processes has become a central topic in community ecology. These processes have focused almost exclusively on habitat filtering and competitive exclusion. Recent evidence, however, indicates that facilitation has been important in preserving biodiversity over evolutionary time, with recent lineages conserving the regeneration niches of older, distant lineages. Here we test whether, if facilitation among distant-related species has preserved the regeneration niche of plant lineages, this has increased the phylogenetic diversity of communities. By analyzing a large worldwide database of species, we showed that the regeneration niches were strongly conserved across evolutionary history. Likewise, a phylogenetic supertree of all species of three communities driven by facilitation showed that nurse species facilitated distantly related species and increased phylogenetic diversity., We thank D. Ackerly, J. Bascompte, R.M. Callaway, R. Cruz, T. Fukami, P. García-Fayos, P. Jordano, J. Pausas and E. Rezende, and three anonymous referees for comments on the ideas conveyed in this article. A. Vital, J.P. Castillo, C. Rodríguez, and M. Morales helped with field samplings. Our research is funded by DGAPA-UNAM, Project IN227605, and Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo, Subprograma Diversidad Biológica (Project XII-6) for travel expenses to A.V.-B.