Hannah E Marx1, Cédric Dentant2, Julien Renaud3, Romain Delunel4, David C Tank1, Sébastien Lavergne3. 1. Department of Biological Sciences, University of Idaho, 875 Perimeter Dr. MS 3051, Moscow, ID 83844-3051, USA. 2. Parc National des Écrins, F-05000, France. 3. Laboratoire d'Ecologie Alpine, CNRS - Université Grenoble Alpes, UMR 5553, F-38000 Grenoble, France. 4. Institute of Geological Sciences, University of Bern, Bern, Switzerland.
Abstract
AIM: Plants occurring on high-alpine summits are generally expected to persist due to adaptations to extreme selective forces caused by the harshest climates where angiosperm life is known to thrive. We assessed the relative effects of this strong environmental filter and of other historical and stochastic factors driving plant community structure in very high-alpine conditions (up to 4,000m). LOCATION: European Alps, Écrins National Park, France. METHODS: Using species occurrence data collected from floristic surveys on 15 summits (2,791 m - 4,102 m a.s.l.) throughout the Écrins range, along with existing molecular sequence data obtained from GenBank, we used a mega-phylogenetic approach to evaluate the phylogenetic structure of high-alpine plant species assemblages. We used three nested species pools and two null models to address the importance of species-specific and species-neutral processes for driving coexistence. RESULTS: Compared to the entire species pool of the study region, alpine summits exhibited a strong signal of phylogenetic clustering. Restricting statistical sampling to environmentally and historically defined species pools reduced the significance of this pattern. However, we could not reject a model that explicitly incorporates neutral colonization and local extinction in shaping community structure for dominant plant orders. Between summits, phylogenetic turnover was generally lower than expected. Environmental drivers did not explain overall phylogenetic patterns, but we found significant geographic and climatic structure in phylogenetic diversity at finer taxonomic scales. MAIN CONCLUSIONS: Although we found evidence for strong phylogenetic clustering within alpine summits, we were not able to reject models of species-neutral processes to explain patterns of floristic diversity. Our results suggest that plant community structure in high-alpine regions can also be shaped by neutral processes, and not through the sole action of environmental selection as traditionally assumed for harsh and stressful environments.
AIM: Plants occurring on high-alpine summits are generally expected to persist due to adaptations to extreme selective forces caused by the harshest climates where angiosperm life is known to thrive. We assessed the relative effects of this strong environmental filter and of other historical and stochastic factors driving plant community structure in very high-alpine conditions (up to 4,000m). LOCATION: European Alps, Écrins National Park, France. METHODS: Using species occurrence data collected from floristic surveys on 15 summits (2,791 m - 4,102 m a.s.l.) throughout the Écrins range, along with existing molecular sequence data obtained from GenBank, we used a mega-phylogenetic approach to evaluate the phylogenetic structure of high-alpine plant species assemblages. We used three nested species pools and two null models to address the importance of species-specific and species-neutral processes for driving coexistence. RESULTS: Compared to the entire species pool of the study region, alpine summits exhibited a strong signal of phylogenetic clustering. Restricting statistical sampling to environmentally and historically defined species pools reduced the significance of this pattern. However, we could not reject a model that explicitly incorporates neutral colonization and local extinction in shaping community structure for dominant plant orders. Between summits, phylogenetic turnover was generally lower than expected. Environmental drivers did not explain overall phylogenetic patterns, but we found significant geographic and climatic structure in phylogenetic diversity at finer taxonomic scales. MAIN CONCLUSIONS: Although we found evidence for strong phylogenetic clustering within alpine summits, we were not able to reject models of species-neutral processes to explain patterns of floristic diversity. Our results suggest that plant community structure in high-alpine regions can also be shaped by neutral processes, and not through the sole action of environmental selection as traditionally assumed for harsh and stressful environments.
Authors: Ragan M Callaway; R W Brooker; Philippe Choler; Zaal Kikvidze; Christopher J Lortie; Richard Michalet; Leonardo Paolini; Francisco I Pugnaire; Beth Newingham; Erik T Aschehoug; Cristina Armas; David Kikodze; Bradley J Cook Journal: Nature Date: 2002-06-20 Impact factor: 49.962
Authors: Fabien Leprieur; Camille Albouy; Julien De Bortoli; Peter F Cowman; David R Bellwood; David Mouillot Journal: PLoS One Date: 2012-08-17 Impact factor: 3.240
Authors: Daijiang Li; Lauren Trotta; Hannah E Marx; Julie M Allen; Miao Sun; Douglas E Soltis; Pamela S Soltis; Robert P Guralnick; Benjamin Baiser Journal: Ecology Date: 2019-07-09 Impact factor: 5.499