title: Photosynthetic innovation broadens the niche within a single species.
abstract: Adaptation to changing environments often requires novel traits, but how such traits directly affect the ecological niche remains poorly understood. Multiple plant lineages have evolved C4 photosynthesis, a combination of anatomical and biochemical novelties predicted to increase productivity in warm and arid conditions. Here, we infer the dispersal history across geographical and environmental space in the only known species with both C4 and non-C4 genotypes, the grass Alloteropsis semialata. While non-C4 individuals remained confined to a limited geographic area and restricted ecological conditions, C4 individuals dispersed across three continents and into an expanded range of environments, encompassing the ancestral one. This first intraspecific investigation of C4 evolutionary ecology shows that, in otherwise similar plants, C4 photosynthesis does not shift the ecological niche, but broadens it, allowing dispersal into diverse conditions and over long distances. Over macroevolutionary timescales, this immediate effect can be blurred by subsequent specialisation towards more extreme niches.
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
authors.forename: Marjorie R
authors.initials: MR
authors.lastname: Lundgren
authors.affiliation: CNRS, Université Toulouse III - Paul Sabatier, ENFA, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), 118 route de Narbonne, 31062, Toulouse, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Besnard
authors.affiliation: Department of Botany, Rhodes University, Grahamstown, 6139, South Africa.
authors.forename: Brad S
authors.initials: BS
authors.lastname: Ripley
authors.affiliation: School of GeoSciences, University of Edinburgh, Crew Building, The King's Buildings, Alexander Crum Brown Road, Edinburgh, EH9 3FF, UK.
authors.forename: Caroline E R
authors.initials: CE
authors.lastname: Lehmann
authors.affiliation: Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Chatelet
authors.affiliation: Royal Botanic Gardens, Kew, Richmond Surrey, TW9 3AB, UK.
authors.forename: Ralf G
authors.initials: RG
authors.lastname: Kynast
authors.affiliation: Department of Biological Sciences, Makerere University, PO Box 7062, Kampala, Uganda.
authors.forename: Mary
authors.initials: M
authors.lastname: Namaganda
authors.affiliation: Royal Botanic Gardens, Kew, Richmond Surrey, TW9 3AB, UK.
authors.forename: Maria S
authors.initials: MS
authors.lastname: Vorontsova
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
authors.forename: Russell C
authors.initials: RC
authors.lastname: Hall
authors.affiliation: National Herbarium of Tanzania, Arusha, Tanzania.
authors.forename: John
authors.initials: J
authors.lastname: Elia
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
authors.forename: Colin P
authors.initials: CP
authors.lastname: Osborne
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
authors.forename: Pascal-Antoine
authors.initials: PA
authors.lastname: Christin
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D005075:Biological Evolution; D017753:Ecosystem; D054628:Genome, Chloroplast; D018745:Genome, Plant; D005838:Genotype; D010788:Photosynthesis; D010802:Phylogeny; D006109:Poaceae / Q000235:genetics* / Q000502:physiology
keywords: Adaptation; Alloteropsis; C4 photosynthesis; ecological niche; evolution; phylogeography