title: Nurse plants transfer more nitrogen to distantly related species.
abstract: Plant facilitative interactions enhance co-occurrence between distant relatives, partly due to limited overlap in resource requirements. We propose a different mechanism for the coexistence of distant relatives based on positive interactions of nutrient sharing. Nutrients move between plants following source-sink gradients driven by plant traits that allow these gradients to establish. Specifically, nitrogen (N) concentration gradients can arise from variation in leaf N content across plants species. As many ecologically relevant traits, we hypothesize that leaf N content is phylogenetically conserved and can result in N gradients promoting N transfer among distant relatives. In a Mexican desert community governed by facilitation, we labelled nurse plants (Mimosa luisana) with15N and measured its transfer to 14 other species in the community, spanning the range of phylogenetic distances to the nurse plant. Nurses established steeper N source-sink gradients with distant relatives, increasing15N transfer toward these species. Nutrient sharing may provide long-term benefits to facilitated plants and may be an overlooked mechanism maintaining coexistence and increasing the phylogenetic diversity of plant communities.
authors.affiliation: Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, A.P. 70-275, C.P. 04510, México D.F, México.|Centro de Investigaciones sobre Desertificación (CIDE, CSIC-UV-GV), Carretera de Moncada-Náquera Km 4.5, 46113, Moncada, Valencia, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Montesinos-Navarro
authors.affiliation: Centro de Investigaciones sobre Desertificación (CIDE, CSIC-UV-GV), Carretera de Moncada-Náquera Km 4.5, 46113, Moncada, Valencia, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Verdú
authors.affiliation: Departamento de Conservación de Suelos y Aguas, Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC), Campus de Espinardo, PO Box 4195, E-30100, Murcia, Spain.
authors.forename: José Ignacio
authors.initials: JI
authors.lastname: Querejeta
authors.affiliation: Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, A.P. 70-275, C.P. 04510, México D.F, México.|Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, México D.F, México.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Valiente-Banuet
mesh_terms: D004777:Environment; D009584:Nitrogen / Q000378:metabolism*; D010802:Phylogeny; D018515:Plant Leaves; D010944:Plants / Q000378:metabolism*
chemical_list: D009584:Nitrogen
keywords: 15N; coexistence; nitrogen transfer; nutrient sharing; phylogenetic distance; plant-plant interactions