Plant functional types: competitors. Johnson grass (Sorghum halepense)

Part of a series showing examples of plant functional types according to Grime's CSR (Competitor, Stress-tolerator and Ruderal) plant ecological strategy scheme. In this example, a 'competitor' or C-selected species, Johnson grass (𝘚𝘰𝘳𝘨𝘩𝘶𝘮 𝘩𝘢𝘭𝘦𝘱𝘦𝘯𝘴𝘦: Poaceae), invading the meadows, borders and maize fields surrounding Villa Arconati, near Milan, Italy (www.villaarconati-far.it/eng). The native range is the Middle East and Central Asia, and in Italy it is an archeophyte (i.e. introduced at some unrecorded moment in antiquity) that is considered naturalized in some regions but invasive (spreading) in others.

Competitor species are adapted to stable, resource rich habitats (plenty of light, nutrients and water) by getting large fast, allowing them to pre-empt resources and exclude other plants. Large-leaved plants exhibit intermediate resource economics (i.e. they are neither extremely acquisitive nor extremely conservative); part of a three-way trade-off fundamental to plant functioning and adaptation. The competitor strategy is not effective where there is regular disturbance (lethal biomass removal) or stress (limitations to metabolism restraining growth) and acquisitive vs. conservative economics, respectively, confer fitness. This is where Grime's wider CSR scheme helps us to understand plant adaptation.

𝗙𝘂𝗻 𝗳𝗮𝗰𝘁: the latin specific name ‘𝘩𝘢𝘭𝘦𝘱𝘦𝘯𝘴𝘦’ was chosen to reflect the geographic origin of the species (the specimen Linneaus examined came from Allepo in Syria). 𝗥𝗲𝗹𝗮𝘁𝗲𝗱 𝗳𝘂𝗻 𝗳𝗮𝗰𝘁: the English name Johnson grass acknowledges the role of Colonel William Johnson in introducing this species to Alabama in 1840 as a forage grass. Nowadays you can find it all over the American continents too. Yay!

𝗧𝗵𝗶𝘀 𝗰𝗵𝗮𝗻𝗻𝗲𝗹 𝗶𝘀 𝗻𝗼𝘁 𝗺𝗼𝗻𝗲𝘁𝗶𝘇𝗲𝗱.

𝗥𝗲𝗹𝗮𝘁𝗲𝗱 𝗹𝗶𝘁𝗲𝗿𝗮𝘁𝘂𝗿𝗲:
Cerabolini, B.E.L., Brusa, G., Ceriani, R.M., De Andreis, R., Luzzaro, A. & Pierce, S. (2010) Can CSR classification be generally applied outside Britain? Plant Ecology, 210: 253-261. www.researchgate.net/publication/225396436_Can_CSR…

Díaz, S., Kattge, J., Cornelissen, J.H.C., Wright, I.J., Lavorel, S., Dray, S., Reu, B., Kleyer, M., Wirth, C., Prentice, I.C., Garnier, E., Bönisch, G., Westoby, M., Poorter, H., Reich, P.B., Moles, A.T., Dickie, J., Gillison, A.N., Zanne, A.E., Chave, J., Wright, S.J., Sheremet’ev, S.N., Jactel, H., Baraloto, C., Cerabolini, B., Pierce, S., et al. (2016) The global spectrum of plant form and function. Nature, 529: 167–171. www.nature.com/articles/nature16489

Grime JP. 1974. Vegetation classification by reference to strategies. Nature 250(5461), 26-31. DOI: 10.1038/250026a0. www.nature.com/articles/250026a0

Grime JP. 1977. Evidence for the existence of three primary strategies in plants and its relevance to ecological and evolutionary theory. The American Naturalist 111(982), 1169-1194. DOI: 10.1086/283244. www.journals.uchicago.edu/doi/10.1086/283244

Grime JP & Pierce S. 2012. The Evolutionary Strategies that Shape Ecosystems. John Wiley & Sons, Ltd. ISBN:9780470674819, DOI:10.1002/9781118223246. onlinelibrary.wiley.com/doi/book/10.1002/978111822…

Pierce, S., Bottinelli, A., Bassani, I., Ceriani, R.M. & Cerabolini, B.E.L. (2014) How well do seed production traits correlate with leaf traits, whole plant traits and plant ecological strategies? Plant Ecology, 215: 1351–1359. www.researchgate.net/publication/264680177_How_wel…

Pierce, S., Brusa, G., Sartori, M. & Cerabolini, B.E.L. (2012) Combined use of leaf size and economics traits allows direct comparison of hydrophyte and terrestrial herbaceous adaptive strategies. Annals of Botany, 109(5): 1047-1053. academic.oup.com/aob/article/109/5/1047/141156

Pierce, S., Brusa, G., Vagge, I. & Cerabolini, B.E.L. (2013) Allocating CSR plant functional types: the use of leaf economics and size traits to classify woody and herbaceous vascular plants. Functional Ecology, 27(4): 1002-1010. besjournals.onlinelibrary.wiley.com/doi/full/10.11…

Pierce, S., Negreiros, D., Cerabolini, B.E.L., Kattge, J., Díaz, S., Kleyer, M., Shipley, B., Wright, S.J., et al. (2017) A global method for calculating plant CSR ecological strategies applied across biomes worldwide. Functional Ecology, 31(2): 444-457. besjournals.onlinelibrary.wiley.com/doi/10.1111/13…


𝗖𝗦𝗥 𝘁𝗿𝗶𝗮𝗻𝗴𝗹𝗲 𝗳𝗶𝗴𝘂𝗿𝗲 𝗿𝗲𝗽𝗿𝗼𝗱𝘂𝗰𝗲𝗱 𝘄𝗶𝘁𝗵 𝗽𝗲𝗿𝗺𝗶𝘀𝘀𝗶𝗼𝗻 𝗳𝗿𝗼𝗺:

Pierce S & Cerabolini BEL. 2018. Plant economics and size trait spectra are both explained by one theory. Economics and Size in Ecology. The Plant Press, Milan. www.researchgate.net/profile/Simon-Pierce/publicat…