QUESTIONS: Traditional null models used to reveal assembly processes from functional diversity patterns are not tailored for comparing different spatial and evolutionary scales. In this study, we present and explore a family of null models that can help disentangling assembly processes at their appropriate scales and thereby elucidate the ecological drivers of community assembly. LOCATION: French Alps. METHODS: Our approach gradually constrains null models by: (1) filtering out species not able to survive in the regional conditions in order to reduce the spatial scale, and (2) shuffling species only within lineages of different ages to reduce the evolutionary scale of the analysis. We first tested and validated this approach using simulated communities. We then applied it to study the functional diversity patterns of the leaf-height-seed strategy of plant communities in the French Alps. RESULTS: Using simulations, we found that reducing the spatial scale correctly detected a signature of competition (functional divergence) even when environmental filtering produced an overlaying signal of functional convergence. However, constraining the evolutionary scale did not change the identified functional diversity patterns. In the case study of alpine plant communities, investigating scale effects revealed that environmental filtering had a strong influence at larger spatial and evolutionary scales and that neutral processes were more important at smaller scales. In contrast to the simulation study results, decreasing the evolutionary scale tended to increase patterns of functional divergence. CONCLUSION: We argue that the traditional null model approach can only identify a single main process at a time and suggest to rather use a family of null models to disentangle intertwined assembly processes acting across spatial and evolutionary scales.

Institute of Botany Academy of Sciences of the Czech Republic Třeboň CZ 379 82 Czech Republic

Laboratoire d'Ecologie Alpine UMR CNRS 5553 Université Joseph Fourier BP 53 Grenoble Cedex 9 38041 France

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Albert CH, Thuiller W, Yoccoz NG, Douzet R, Aubert S, Lavorel S. A multi-trait approach reveals the structure and the relative importance of intravs. interspecific variability in plant traits. Functional Ecology. 2010;24:1192–1201.

Blomberg SP, Garland T, Jr, Ives AR. Testing for phylogenetic signal in comparative data: behavioral traits are more labile. Evolution. 2003;57:717–745. PubMed

Boulangeat I, Gravel D, Thuiller W. Accounting for dispersal and biotic interactions to disentangle the drivers of species distributions and their abundances. Ecology Letters. 2012a;15:584–593. PubMed PMC

Boulangeat I, Lavergne S, Van Es J, Garraud L, Thuiller W. Niche breadth, rarity and ecological characteristics within a regional flora spanning large environmental gradients. Journal of Biogeography. 2012b;39:204–214.

Carboni M, Acosta A, Ricotta C. Differences in functional diversity among plant communities on Mediterranean coastal dunes are driven by their phylogenetic history. Journal of Vegetation Science. 2013;24:932–941.

Cavender-Bares J, Kozak KH, Fine PVA, Kembel SW. The merging of community ecology and phylogenetic biology. Ecology Letters. 2009;12:693–715. PubMed

Clark JS, Bell DM, Hersh MH, Kwit MC, Moran E, Salk C, Stine A, Valle D, Zhu K. Individual-scale variation, species-scale differences: inference needed to understand diversity. Ecology Letters. 2011;14:1273–1287. PubMed

Crisp MD, Arroyo MTK, Cook LG, Gandolfo MA, Jordan GJ, McGlone MS, Weston PH, Westoby M, Wilf P, Linder HP. Phylogenetic biome conservatism on a global scale. Nature. 2009;458:754–756. PubMed

de Bello F. The quest for trait convergence and divergence in community assembly: are null models the magic wand? Global Ecology and Biogeography. 2012;21:312–317.

de Bello F, Lepš J, Sebastia M-T. Variations in species and functional plant diversity along climatic and grazing gradients. Ecography. 2006;29:801–810.

de Bello F, Lavorel S, Lavergne S, Albert CH, Boulangeat I, Mazel F, Thuiller W. Hierarchical effects of environmental filters on the functional structure of plant communities: a case study in the French Alps. Ecography. 2012a;36:393–402.

de Bello F, Price JN, Münkemüller T, Liira J, Zobel M, Thuiller W, Gerhold P, Götzenberger L, Lavergne S, Lepš I, Zobel K, Pärtel M. Functional trait pools to determine biotic community assembly. Ecology. 2012b;93:2263–2273. PubMed

Diamond JM. Assembly of species communities. In: Cody ML, Diamond JM, editors. Ecology and evolution of communities. Harvard University Press; Cambridge, MA, US: 1975. pp. 342–444.

Gerhold P, Price J, Püssa K, Kalamees R, Aher K, Kaasik A, Pärtel M. Functional and phylogenetic community assembly linked to species loss and gain in a long-term resource manipulation experiment. Journal of Vegetation Science. 2013;24:843–852.

Gotelli NJ, Ulrich W. Statistical challenges in null model analysis. Oikos. 2012;121:171–180.

Gotelli NJ, Graves GR, Rahbek C. Macroecological signals of species interactions in the Danish avifauna. Proceedings of the National Academy of Sciences of the United States of America. 2010;107:5030. PubMed PMC

Grime JP. Trait convergence and trait divergence in herbaceous plant communities: mechanisms and consequences. Journal of Vegetation Science. 2006;17:255–260.

Guisan A, Thuiller W. Predicting species distribution: offering more than simple habitat models. Ecology Letters. 2005;8:993–1009. PubMed

Hardy OJ, Senterre B. Characterizing the phylogenetic structure of communities by an additive partitioning of phylogenetic diversity. Journal of Ecology. 2007;95:493–506.

Hintze JL, Nelson RD. Violin plots: a box plot-density trace synergism. American Statistician. 1998;52:181–184.

Körner C. Alpine plant life – functional plant ecology of high mountain ecosystems. Springer; Berlin, DE: 2003.

Kraft NJB, Cornwell WK, Webb CO, Ackerly DD. Trait evolution, community assembly, and the phylogenetic structure of ecological communities. The American Naturalist. 2007;170:271–283. PubMed

Laliberté E, Norton D, Scott D. Plant trait dispersion patterns under long-term shifts in resource availability and disturbance challenge: common assumptions about community assembly processes. Journal of Vegetation Science. 2013;24:834–842.

Lavergne S, Garnier E, Debussche M. Do rock endemic and widespread plant species differ under the Leaf-Height-Seed plant ecology strategy scheme? Ecology Letters. 2003;6:398–404.

Lavorel S, Garnier E. Predicting changes in community composition and ecosystem functioning from plant traits: revisiting the Holy Grail. Functional Ecology. 2002;16:545–556.

MacArthur R, Levins R. The limiting similarity, convergence, and divergence of coexisting species. The American Naturalist. 1967;37:7–385.

Mayfield MM, Levine JM. Opposing effects of competitive exclusion on the phylogenetic structure of communities. Ecology Letters. 2010;13:1085–1093. PubMed

Mitchell MGE, Cahill JF, Jr, Hik DS. Plant interactions are unimportant in a subarctic-alpine plant community. Ecology. 2009;90:2360–2367. PubMed

Mouquet N, Devictor V, Meynard CN, Munoz F, Bersier L-F, Chave J, Couteron P, Dalecky A, Fontaine C, Gravel D, Hardy OJ, Jabot F, Lavergne S, Leibold M, Mouillot D, Münkemüller T, Pavoine S, Prinzing A, Rodrigues ASL, Rohr RP, Thébault E, Thuiller W. Ecophylogenetics: advances and perspectives. Biological Reviews. 2012;87:769–785. PubMed

Münkemüller T, de Bello F, Meynard CN, Gravel D, Lavergne S, Mouillot D, Mouquet N, Thuiller W. From diversity indices to community assembly processes: a test with simulated data. Ecography. 2012;35:468–480.

Pagel M. Inferring the historical patterns of biological evolution. Nature. 1999;401:877–884. PubMed

Pakeman RJ, Quested HM. Sampling plant functional traits: what proportion of the species need to be measured? Applied Vegetation Science. 2007;10:91–96.

Pakeman RJ, Garnier E, Lavorel S, Ansquer P, Castro H, Cruz P, Dolezal J, Eriksson O, Freitas H, Golodets C, Kigel J, Kleyer M, Lepš J, Meier T, Papadimitriou M, Papanastasis VP, Quested H, Quétier F, Rusch G, Sternberg M, Theau J-P, Thébault A, Vile D. Impact of abundance weighting on the response of seed traits to climate and land use. Journal of Ecology. 2008;96:355–366.

Pärtel M, Szava-Kovats R, Zobel M. Dark diversity: shedding light on absent species. Trends in Ecology & Evolution. 2011;26:124–128. PubMed

Pavoine S, Dolédec S. The apportionment of quadratic entropy: a useful alternative for partitioning diversity in ecological data. Environmental and Ecological Statistics. 2005;12:125–138.

Peres-Neto PR, Olden JD, Jackson DA. Environmentally constrained null models: site suitability as occupancy criterion. Oikos. 2001;93:110–120.

Petchey OL, Evans KL, Fishburn IS, Gaston KJ. Low functional diversity and no redundancy in British avian assemblages. Journal of Animal Ecology. 2007;76:977–985. PubMed

Quétier F, Thébault A, Lavorel S. Plant traits in a state and transition framework as markers of ecosystem response to land-use change. Ecological Monographs. 2007;77:33–52.

Rao CR. Diversity and dissimilarity coefficients: a unified approach. Theoretical Population Biology. 1982;21:24–43.

Ricklefs RE. A comprehensive framework for global patterns in biodiversity. Ecology Letters. 2004;7:1–15.

Ricotta C. Additive partitioning of Rao’s quadratic diversity: a hierarchical approach. Ecological Modelling. 2005;183:365–371.

Roquet C, Lavergne S, Thuiller W. Building megaphylogenies for macroecology: taking up the challenge. Ecography. 2013;36:13–26. PubMed PMC

Spasojevic MJ, Suding KN. Inferring community assembly mechanisms from functional diversity patterns: the importance of multiple assembly processes. Journal of Ecology. 2012;100:652–661.

Swenson NG, Enquist BJ, Pither J, Thompson J, Zimmerman JK. The problem and promise of scale dependency in community phylogenetics. Ecology. 2006;87:2418–2424. PubMed

Thuiller W, Gallien L, Boulangeat I, de Bello F, Münkemüller T, Roquet C, Lavergne S. Resolving Darwin’s naturalization conundrum: a quest for evidence. Diversity and Distributions. 2010;16:461–475.

Vamosi SM, Heard SB, Vamosi JC, Webb CO. Emerging patterns in the comparative analysis of phylogenetic community structure. Molecular Ecology. 2009;18:572–592. PubMed

Weiher E, Keddy PA. Assembly rules, null models, and trait dispersion: new questions from old patterns. Oikos. 1995;74:159–164.

Weiher E, van der Werf A, Thompson K, Roderick M, Garnier E, Eriksson O. Challenging Theophrastus: a common core list of plant traits for functional ecology. Journal of Vegetation Science. 1999;10:609–620.

Westoby M. A leaf–height–seed (LHS) plant ecology strategy scheme. Plant and Soil. 1998;199:213–227.

Willis CG, Halina M, Lehman C, Reich PB, Keen A, McCarthy S, Cavender-Bares J. Phylogenetic community structure in Minnesota oak savanna is influenced by spatial extent and environmental variation. Ecography. 2010;33:565–577.

Zobel M. The relative role of species pools in determining plant species richness: an alternative explanation of species coexistence? Trends in Ecology & Evolution. 1997;12:266–269. PubMed