Palaeozoic landscapes shaped by plant evolution

Journal name:
Nature Geoscience
Year published:
Published online


Fluvial landscapes diversified markedly over the 250 million years between the Cambrian and Pennsylvanian periods. The diversification occurred in tandem with the evolution of vascular plants and expanding vegetation cover. In the absence of widespread vegetation, landscapes during the Cambrian and Ordovican periods were dominated by rivers with wide sand-beds and aeolian tracts. During the late Silurian and Devonian periods, the appearance of vascular plants with root systems was associated with the development of channelled sand-bed rivers, meandering rivers and muddy floodplains. The widespread expansion of trees by the Early Pennsylvanian marks the appearance of narrow fixed channels, some representing anabranching systems, and braided rivers with vegetated islands. We conclude that the development of roots stabilized the banks of rivers and streams. The subsequent appearance of woody debris led to log jams that promoted the rapid formation of new river channels. Our contention is supported by studies of modern fluvial systems and laboratory experiments. In turn, fluvial styles influenced plant evolution as new ecological settings developed along the fluvial systems. We suggest that terrestrial plant and landscape evolution allowed colonization by an increasingly diverse array of organisms.

At a glance


  1. Palaeozoic events of fluvial and landscape development, in relation to plant evolution and atmospheric change.
    Figure 1: Palaeozoic events of fluvial and landscape development, in relation to plant evolution and atmospheric change.

    Data sources: atmospheric CO2 and O2 curves11, employing volcanic weathering factor in CO2 curve, and carbon burial curve12 (curves have wide error bars); fluvial styles and vascular-plant events14, 18, 37, 55; numbers of plant families in time intervals and their origination rates96, 97; plant nutritional traits29; events of rapid vegetation expansion, inferred from isotopic excursions at the Siluro–Devonian boundary34 and at the Famennian–Frasnian boundary (Late Devonian)41; key events in animal evolution88, 90, 93, 94, 98, 99; geological timescale100. Protero., Proterozoic; Miss., Mississippian; Penn., Pennsylvanian; Serp., Serpukhovian; Vis., Visean; Tour., Tournaisian; Prid., Pridolian; Lud., Ludfordian; Wen., Wenlockian; Llan., Llandovery.

  2. Plants and fluvial systems in ancient and modern settings.
    Figure 2: Plants and fluvial systems in ancient and modern settings.

    a, Braided-fluvial sheets, Alderney Sandstone, Cambrian, Channel Islands. b, Rhynia (R) and Aglaophyton (A) in growth position in hotspring silica, Rhynie Chert, Pragian, Scotland. Pound coin is 2.3 cm in diameter (See Fig. 6a,b of ref. 31 for more detail). Image courtesy of N. Trewin. c, Lycopsid trees, arrowed, rooted in former peat (coal seam), Sydney Mines Formation, Middle Pennsylvanian, Canada. Hammer (centre, right) is 30 cm long. d, Fixed-channel body of sandstone and mudstone, possibly deposited by an anastomosing river, with red mudstone and crevasse-splay sandstone, Joggins Formation, Canada. e, Anastomosing Diamantina River, Queensland, Australia, with eucalyptus trees (Eucalyptus microtheca) along riparian zones. f, Extensive eucalyptus roots exposed by bank erosion, Thomson River, Queensland, Australia.

  3. Palaeozoic diversification of fluvial style.
    Figure 3: Palaeozoic diversification of fluvial style.

    Proportions of rock units with braided, meandering and fixed-channel styles based on assessment of 330 rock units14, 55. Meandering rivers were identified by heterolithic lateral-accretion sets, and fixed channels by ribbons to narrow sheets with vertically aggraded fill. The proportion of channelled-braided and island-braided styles is estimated, as few literature descriptions provide sufficient detail for assessment. Penn., Pennsylvanian; Miss., Mississipian; Dev., Devonian; Sil., Silurian; Ord., Ordovician; Camb., Cambrian; Protero.; Proterozoic.

  4. Experimental study of effects of vegetation on channels.
    Figure 4: Experimental study of effects of vegetation on channels.

    Meandering channel created in flume at St Anthony Falls Laboratory, Minneapolis. Following initial set-up of a braided channel, seeding with alfalfa (green) during low-discharge periods stabilized the banks and resulted in restriction of flow to a self-maintaining single-thread channel, shown with red dye. The channel migrated systematically, and was bordered by a stable floodplain80. A flume length of 10 m is shown, viewed during low flow. Image courtesy of M. Tal.


  1. Corenblit, D. et al. Feedbacks between geomorphology and biota controlling Earth surface processes and landforms: A review of foundation concepts and current understandings. Earth Sci. Rev. 106, 307331 (2011).
  2. Montgomery, D. R. & Piégay, H. Wood in rivers: interactions with channel morphology and processes. Geomorphology 51, 15 (2003).
  3. Darwin, C. The Formation of Vegetated Mould through the Action of Worms with Observation of their Habitats (John Murray, 1883).
  4. Corenblit, D., Steiger, J., Gurnell, A. M. & Tabacchi, E. Darwinian origin of landforms. Earth Surf. Proc. Land. 32, 20702073 (2007).
  5. Fisher, S. G., Heffernan, J. B., Sponseller, R. A. & Welter, J. R. Functional ecomorphology: Feedbacks between form and function in fluvial landscape ecosystems. Geomorphology 89, 8496 (2007).
  6. Murray, A. B., Knaapen, M. A. F., Tal, M. & Kirwan, M. L. Biomorphodynamics: Physical-biological feedbacks that shape landscapes. Water Resour. Res. 44, W11301 (2008).
  7. Osterkamp, W. R., Hupp, C. R. & Stoffel, M. The interactions between vegetation and erosion: new directions for research at the interface of ecology and geomorphology. Earth Surf. Proc. Land. (2011).
  8. Jones, C. G., Lawton, J. H. & Shachak, M. Organisms as ecosystem engineers. Oikos 69, 373386 (1994).
  9. Algeo, T. J., Berner, R. A., Maynard, J. B. & Scheckler, S. E. Late Devonian oceanic anoxic events and biotic crises: “Rooted” in the evolution of vascular land plants? GSA Today 5, 6466 (1995).
  10. Algeo, T. J. & Scheckler, S. E. Terrestrial-marine teleconnections in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events. Philos. Trans. R. Soc. Lond. B 353, 113130 (1998).
  11. Berner, R. A. GEOCARBSULF: A combined model for Phanerozoic atmospheric O2 and CO2. Geochim. Cosmochim. Acta 70, 56535664 (2006).
  12. Berner, R. A. The long-term carbon cycle, fossil fuels and atmospheric composition. Nature 426, 323326 (2003).
  13. Schumm, S. A. Speculations concerning paleohydrologic controls of terrestrial sedimentation. Geol. Soc. Am. Bull. 79, 15731588 (1968).
  14. Davies, N. S. & Gibling, M. R. Cambrian to Devonian evolution of alluvial systems: The sedimentological impact of the earliest land plants. Earth Sci. Rev. 98, 171200 (2010).
  15. Cotter, E. in Fluvial Sedimentology (ed. Miall, A. D.) 361383 (Canadian Society of Petroleum Geologists Memoir 5, 1978).
  16. Long, D. G. F. in The Precambrian Earth: Tempos and Events (eds Eriksson, P. G., Altermann, W., Nelson, D. R., Mueller, W. U. & Catuneanu, O.) 660663 (Elsevier, 2004).
  17. Long, D. G. F. in From River to Rock Record: The Preservation of Fluvial Sediments and their subsequent Interpretation (eds Davidson, S., Leleu, S. & North, C. P.) 3761 (SEPM, 2011).
  18. Davies, N. S., Gibling, M. R. & Rygel, M. C. Alluvial facies evolution during the Palaeozoic greening of the continents: case studies, conceptual models and modern analogues. Sedimentology 58, 220258 (2011).
  19. Dott, R. H. Jr & Byers, C. W. SEPM research conference on modern shelf and ancient cratonic sedimentation - the orthoquartzite-carbonate suite revisited. J. Sedim. Petrol. 51, 329347 (1981).
  20. Dott, R. H. Jr, Byers, C. W., Fielder, G. W., Stenzel, S. R. & Winfree, K. E. Aeolian to marine transition in Cambro-Ordovician cratonic sheet sandstones of the northern Mississippi valley, U. S. A.. Sedimentology 33, 345367 (1986).
  21. Dott, R. H. Jr The importance of eolian abrasion in supermature quartz sandstones and the paradox of weathering on vegetation-free landscapes. J. Geol. 111, 387405 (2003).
  22. Dalrymple, R. W., Narbonne, G. M. & Smith, L. Eolian action and the distribution of Cambrian shales in North America. Geology 13, 607610 (1985).
  23. Went, D. J. Pre-vegetation alluvial fan facies and processes: an example from the Cambro-Ordovician Rozel Conglomerate Formation, Jersey, Channel Islands. Sedimentology 52, 693713 (2005).
  24. Kennedy, M., Droser, M., Mayer, L. M., Pevear, D. & Mrofka, D. Late Precambrian oxygenation; inception of the clay mineral factory. Science 311, 14461449 (2006).
  25. Taylor, W. A. & Strother, P. K. Ultrastructure of some Cambrian palynomorphs from the Bright Angel Shale, Arizona, USA. Rev. Palaeobot. Palyno. 151, 4150 (2008).
  26. Steemans, P. et al. Origin and radiation of the earliest vascular land plants. Science 324, 353 (2009).
  27. Tomescu, A. M. F., Pratt, L. M., Rothwell, G. W., Strother, P. K. & Nadon, G. C. Carbon isotopes support the presence of extensive land floras pre-dating the origin of vascular plants. Palaeogeogr. Palaeoclimatol. Palaeoecol. 283, 4659 (2009).
  28. Rubinstein, C. V., Gerrienne, P., de la Puente, G. S. L., Astini, R. A. & Steemans, P. Early Middle Ordovician evidence for land plants in Argentina (eastern Gondwana). New Phytol. 188, 365369 (2010).
  29. Raven, J. A. & Andrews, M. Evolution of tree nutrition. Tree Physiol. 30, 10501071 (2010).
  30. Kidston, R. & Lang, W. H. On Old Red Sandstone plants showing structure, from the Rhynie Chert Bed, Aberdeenshire. Part I. Rhynia gwynne-vaughani, Kidston and Lang. Trans. R. Soc. Edin. 51, 761784 (1917).
  31. Trewin, N. H., Fayers, S. R. & Kelman, R. Subaqueous silicification of the contents of small ponds in an Early Devonian hot-spring complex, Rhynie, Scotland. Can. J. Earth Sci. 40, 16971712 (2003).
  32. Dawson, J. W. On the fossil plants from the Devonian rocks of Canada. Q. J. Geol. Soc. Lond. 15, 477488 (1859).
  33. Boyce, C. K. et al. Devonian landscape heterogeneity recorded by a giant fungus. Geology 35, 399402 (2007).
  34. Mal strokekowski, K. & Racki, G. A global biogeochemical perturbation across the Silurian-Devonian boundary: Ocean-continent-biosphere feedbacks. Palaeogeogr. Palaeoclimatol. Palaeoecol. 276, 244254 (2009).
  35. Glasspool, I. J., Edwards, D. & Axe, L. Charcoal in the Early Devonian: A wildfire-derived Konservat-Lagerstatte. Rev. Palaeobot. Palyno. 142, 131136 (2006).
  36. Gerrienne, P. et al. A simple type of wood in two Early Devonian plants. Science 333, 837 (2011).
  37. Davies, N. S. & Gibling, M. R. Paleozoic vegetation and the Siluro-Devonian rise of fluvial lateral accretion sets. Geology 38, 5154 (2010).
  38. Kennedy, K. & Gibling, M. R. The Campbellton Formation of New Brunswick, Canada: paleoenvironments in an important Early Devonian terrestrial locality. Can. J. Earth Sci. 48, 48, 15611580 (2011).
  39. Stein, W. E., Mannolini, F., Hernick, L. V., Landing, E. & Berry, C. M. Giant cladoxylopsid trees resolve the enigma of the Earth's earliest forest stumps at Gilboa. Nature 446, 904907 (2007).
  40. Mintz, J. S., Driese, S. G. & White, J. D. Environmental and ecological variability of Middle Devonian (Givetian) forests in Appalachian Basin paleosols, New York, United States. Palaios 25, 8596 (2010).
  41. Godderis, Y. & Joachimski, M. M. Global change in the Late Devonian: modelling the Frasnian-Famennian short-term carbon isotope excursions. Palaeogeogr. Palaeoclimatol. Palaeoecol. 202, 309329 (2004).
  42. Decombeix, A.-L., Meyer-Berthaud, B. & Galtier, J. Transitional changes in arborescent lignophytes at the Devonian - Carboniferous boundary. J. Geol. Soc. Lond. 168, 547557 (2011).
  43. Falcon-Lang, H. J. & Galtier, J. Anatomically-preserved tree-trunks in late Mississippian (Serpukhovian, late Pendleian-Arnsbergian) braided fluvial channel facies, near Searston, southwest Newfoundland, Canada. Rev. Palaeobot. Palynol. 160, 154162 (2010).
  44. Falcon-Lang, H. J. & Bashforth, A. R. Morphology, anatomy, and upland ecology of large cordaitalean trees from the Middle Pennsylvanian of Newfoundland. Rev. Palaeobot. Palynol. 135, 223243 (2005).
  45. DiMichele, W. A., Cecil, C. B., Montañez, I. P. & Falcon-Lang, H. J. Cyclic changes in Pennsylvanian paleoclimate and effects on floristic dynamics in tropical Pangaea. Int. J. Coal Geol. 83, 329344 (2010).
  46. Falcon-Lang, H. J. et al. Incised channel fills containing conifers indicate that seasonally dry vegetation dominated Pennsylvanian tropical lowlands. Geology 37, 923926 (2009).
  47. Falcon-Lang, H. J. et al. Pennsylvanian coniferopsid forests in sabkha facies reveal the nature of seasonal tropical biome. Geology 39, 371374 (2011).
  48. Fielding, C. R., Allen, J. P., Alexander, J. & Gibling, M. R. A facies model for fluvial systems in the seasonal tropics and subtropics. Geology 37, 623626 (2009).
  49. Hacke, U. G., Sperry, J. S., Pockman, W. T., Davis, S. D. & McCulloh, K. A. Trends in wood density and structure are linked to prevention of xylem implosion by negative pressure. Oecologia 126, 457461 (2001).
  50. Canadell, J. et al. Maximum rooting depth of vegetation types at the global scale. Oecologia 108, 583595 (1996).
  51. Gastaldo, R. A. & Degges, C. W. Sedimentology and paleontology of a Carboniferous log jam. Int. J. Coal Geol. 69, 103118 (2007).
  52. Gibling, M. R., Bashforth, A. R., Falcon-Lang, H. J., Allen, J. P. & Fielding, C. R. Log jams and flood sediment buildup caused channel abandonment and avulsion in the Pennsylvanian of Atlantic Canada. J. Sedim. Res 80, 268287 (2010).
  53. Nichols, G. J. & Jones, T. P. Fusain in Carboniferous shallow marine sediments, Donegal, Ireland: the sedimentological effects of wildfire. Sedimentology 39, 487502 (1992).
  54. Marriott, S. B., Wright, V. P. & Williams, B. P. J. in Fluvial Sedimentology VII (eds Blum, M. D., Marriott, S. B. & Leclair, S. F.) 517529 (Blackwell, 2005).
  55. Davies, N. S. & Gibling, M. R. Evolution of fixed-channel alluvial plains in response to Carboniferous vegetation. Nature Geosci. 4, 629633 (2011).
  56. Gurnell, A. M. et al. Wood storage within the active zone of a large European gravel-bed river. Geomorphology 34, 5572 (2000).
  57. Rygel, M. C., Gibling, M. R. & Calder, J. H. Vegetation-induced sedimentary structures from fossil forests in the Pennsylvanian Joggins Formation, Nova Scotia. Sedimentology 51, 531552 (2004).
  58. Bashforth, A. R., Drabkova, J., Oplustil, S., Gibling, M. R. & Falcon-Lang, H. J. Landscape gradients and patchiness in riparian vegetation on a Middle Pennsylvanian braided river plain prone to flood disturbance (Nyrany Member, Central and Western Bohemian Basin, Czech Republic). Rev. Palaeobot. Palynol. 163, 153189 (2010).
  59. Clarke, J. T., Warnock, R. C. M. & Donoghue, P. C. J. Establishing a time-scale for plant evolution. New Phytol. 192, 266301 (2011).
  60. Gibling, M. R., Nanson, G. G. & Maroulis, J. C. Anastomosing river sedimentation in the Channel Country of central Australia. Sedimentology 45, 595619 (1998).
  61. Tooth, S. & Nanson, G. C. The role of vegetation in the formation of anabranching channels in an ephemeral river, Northern plains, arid central Australia. Hydrol. Process. 14, 30993117 (2000).
  62. Tooth, S., Jansen, J. D., Nanson, G. C., Coulthard, T. J. & Pietsch, T. Riparian vegetation and the late Holocene development of an anabranching river: Magela Creek, northern Australia. Geol. Soc. Am. Bull. 120, 10211035 (2008).
  63. Harwood, K. & Brown, A. G. Changing in-channel and overbank flood velocity distributions and the morphology of forested multiple channel (anastomosing) systems. Earth Surf. Proc. Land. 18, 741748 (1993).
  64. Rodrigues, S., Bréhéret, J.-G., Macaire, J.-J., Greulich, S. & Villar, M. In-channel woody vegetation controls on sedimentary processes and the sedimentary record within alluvial environments: a modern example of an anabranch of the River Loire, France. Sedimentology 54, 223242 (2007).
  65. Abernethy, B. & Rutherfurd, I. D. The effect of riparian tree roots on the mass-stability of riverbanks. Earth Surf. Proc. Land. 25, 921937 (2000).
  66. Dupuy, L., Fourcaud, T. & Stokes, A. A numerical investigation into the influence of soil type and root architecture on tree anchorage. Plant Soil 278, 119134 (2005).
  67. Pollen, N. Temporal and spatial variability in root reinforcement of streambanks: Accounting for soil shear strength and moisture. Catena 69, 197205 (2007).
  68. Hales, T. C., Ford, C. R., Hwang, T., Vose, J. M. & Band, L. E. Topographic and ecologic controls on root reinforcement. J. Geophys. Res. 114, F03013 (2009).
  69. Abbe, T. B. & Montgomery, D. R. Patterns and processes of wood debris accumulation in the Queets river basin, Washington. Geomorphology 51, 81107 (2003).
  70. Webb, A. A. & Erskine, W. D. Distribution, recruitment, and geomorphic significance of large woody debris in an alluvial forest stream: Tonghi Creek, southeastern Australia. Geomorphology 51, 109126 (2003).
  71. Francis, R. A., Petts, G. E. & Gurnell, A. M. Wood as a driver of landscape change along river corridors. Earth Surf. Proc. Land. 33, 16221626 (2008).
  72. Francis, R. A., Corenblit, D. & Edwards, P. J. Perspectives on biogeomorphology, ecosystem engineering and self-organisation in island-braided fluvial ecosystems. Aquat. Sci. 71, 290304 (2009).
  73. Nanson, G. C., Barbetti, M. & Taylor, G. River stabilisation due to changing climate and vegetation during the late Quaternary in western Tasmania, Australia. Geomorphology 13, 145158 (1995).
  74. Brooks, A. P., Brierley, G. J. & Millar, R. G. The long-term control of vegetation and woody debris on channel and flood-plain evolution: insights from a paired catchment study in southeastern Australia. Geomorphology 51, 729 (2003).
  75. Brown, A. G. Learning from the past: palaeohydrology and palaeoecology. Freshwater Biol. 47, 817829 (2002).
  76. Davies, N. S. & Sambrook Smith, G. Signatures of quaternary fluvial response, Upper River Trent, Staffordshire, UK: A synthesis of outcrop, documentary, and GPR data. Z. Geomorphol. 50, 347374 (2006).
  77. Gran, K. & Paola, C. Riparian vegetation controls on braided stream dynamics. Water Resour. Res. 37, 32753283 (2001).
  78. Murray, A. B. & Paola, C. Modelling the effect of vegetation on channel pattern in bedload rivers. Earth Surf. Proc. Land. 28, 131143 (2003).
  79. Coulthard, T. J. Effects of vegetation on braided stream pattern and dynamics. Water Resour. Res. 41, W04003 (2005).
  80. Tal, M. & Paola, C. Dynamic single-thread channels maintained by the interaction of flow and vegetation. Geology 35, 347350 (2007).
  81. Braudrick, C. A., Dietrich, W. E., Leverich, G. T. & Sklar, L. S. Experimental evidence for the conditions necessary to sustain meandering in coarse-bedded rivers. Proc. Natl Acad. Sci. USA 106, 1693616941 (2009).
  82. Perona, P. et al. Biomass selection by floods and related timescales: Part 1. Experimental observations. Adv. Water Resour. (2011).
  83. Edmaier, K., Burlando, P. & Perona, P. Mechanisms of vegetation uprooting by flow in alluvial non-cohesive sediment. Hydrol. Earth Syst. Sci. 15, 16151627 (2011).
  84. Corenblit, D. & Steiger, J. Vegetation as a major conductor of geomorphic changes on the Earth surface: toward evolutionary geomorphology. Earth Surf. Proc. Land. 34, 891896 (2009).
  85. Buatois, L. A. et al. Colonization of brackish-water systems through time: evidence from the trace-fossil record. Palaios 20, 321347 (2005).
  86. Brasier, A. T. Searching for travertines, calcretes and speleothems in deep time: Processes, appearances, predictions and the impact of plants. Earth Sci. Rev. 104, 213239 (2011).
  87. Naiman, R. J., Bilby, R. E. & Bisson, P. A. Riparian ecology and management in the Pacific coastal rain forest. BioSciences 50, 9961011 (2000).
  88. MacNaughton, R. B. et al. First steps on land: Arthropod trackways in Cambrian-Ordovician eolian sandstone, southeastern Ontario, Canada. Geology 30, 391394 (2002).
  89. Davies, N. S., Gibling, M. R. & Rygel, M. C. Marine influence in the Juniata Formation (Upper Ordovician, Potters Mills, Pennsylvania): Implications for the history of life on land. Palaios 25, 527539 (2011).
  90. Buatois, L. A., Mangano, M. G., Genise, J. F. & Taylor, T. N. The ichnologic record of the continental invertebrate invasion: Evolutionary trends in environmental expansion, ecospace utilization, and behavioral complexity. Palaios 13, 217240 (1998).
  91. Buatois, L. A. & Mangano, M. G. in Trace Fossils Concepts, Problems, Prospects (ed. Miller, W. I.) 285323 (Elsevier, 2007).
  92. Labandeira, C. The origin of herbivory on land: Initial patterns of plant tissue consumption by arthropods. Insect Sci. 14, 259275 (2007).
  93. Boucot, A. J. & Janis, C. Environment of the early Paleozoic vertebrates. Palaeogeogr. Palaeoclimatol. Palaeoecol. 41, 251287 (1983).
  94. Niedzwiedzki, G., Szrek, P., Narkiewicz, K., Narkiewicz, M. & Ahlberg, P. E. Tetrapod trackways from the early Middle Devonian period from Poland. Nature 463, 4348 (2010).
  95. Sues, H.-D. & Reisz, R. R. Origins and early evolution of herbivory in tetrapods. Trends Ecol. Evol. 13, 141145 (1998).
  96. Cascales-Miñana, B. New insights into the reading of Paleozoic plant fossil record discontinuities. Hist. Biol. 23, 115130 (2011).
  97. Cascales-Miñana, B. & Cleal, C. J. Plant fossil record and survival analyses. Lethaia 45, 7182 (2011).
  98. Labandeira, C. C., Beall, B. S. & Hueber, F. M. Early insect diversification: Evidence from a Lower Devonian bristletail from Quebec. Science 242, 913916 (1988).
  99. Labandeira, C. C. Invasion of the continents: cyanobacterial crusts to tree-inhabiting arthropods. Trends Ecol. Evol. 20, 253262 (2005).
  100. Gradstein, F. M., Ogg, J. G., Smith, A. G., Bleeker, W. & Lourens, L. J. A new geologic time scale with special reference to Precambrian and Neogene. Episodes 27, 83100 (2004).

Download references

Author information


  1. Department of Earth Sciences, Dalhousie University, PO Box 15000, Halifax, Nova Scotia, Canada B3H 4R2

    • Martin R. Gibling &
    • Neil S. Davies
  2. Present address: Department of Geology and Soil Sciences, Krijgslaan 281, S8, University of Ghent, 9000 Ghent, Belgium

    • Neil S. Davies


M.R.G. and N.S.D. jointly conceived and undertook the study and fieldwork involved. Both authors contributed to the writing of the manuscript and figure construction.

Competing financial interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to:

Author details

Additional data