Supplementary Table S1: Phenotypic traits harboring intraspecific genetic variation that impacts
plant species co-existence
Trait
Chemical traits:
Mechanisms mediating effect on plant co-existence
Citations
Qualitative and
quantitative variation
in monoterpenes
produced in leafs and
needles.
Increases habitat heterogeneity.
Phytotoxic effects vary among monoterpenes, and with the
identity of associated species. Species-specific responses to
monoterpenes can impact competitive hierarchies.
1-5
Quantitative variation
in production of
sinigrin (glucosinolate)
in leafs
Creates negative frequency dependent feedback that is
stabilizing species co-existence. Intraspecific variation in
sinigrin production creates a trade-off between intra- and
interspecific competition leading to intransitive competition
among species and genotypes. Negative impact of high
sinigrin producers on heterospecifics possibly due to sinigrin
lowering the abundance of mutualistic arbuscular
mychorrhizae.
6-8
Chemical composition
of root exudates
Alters root growth and strength of competition. Allocation to
root growth can vary with genetic relatedness of conspecifics
and short term co-evolutionary history with heterospecific
plant species.
Impacts intraspecific competition when strength of
intraspecific competition differs between genetically related
versus unrelated conspecifics.
Impacts interspecific competition when root exudates affect
allocation to root growth differently depending on previous
encounters with neighbors.
9-15&
Architectural traits:
Intraspecific variation
in cushion morphology
Increases habitat heterogeneity (local soil properties, light
16-22
availability). Interaction with cushion plants can vary from
competitive to facilitative depending on cushion morphology.
Tree bark texture
Variation among genotypes in bark texture increases habitat
heterogeneity and affects species composition of bark
epiphytes communities.
23-24
Root system
architecture
Intraspecific genetic variation exists and is expected to
impact plant neighbor interactions, but only few empirical
25-27
studies explicitly test impact of intraspecific variation in root
architecture on species co-existence.
Gender dimorphism
Creates intraspecific variation in competition when male and 28
female plants differ in cost of reproduction. The sex with the
highest reproductive cost shows reduced competitive effect
on neighbor plants.
Hyperaccumulation
Impact on neighbor plants varies with metal concentration in 29-34
Intraspecific variation
soil. Impact on neighbors can be positive when
in ability to accumulate hyperaccumulators reduce the level of heavy metal (i.e.
heavy metals
polluted soils), and negative in non-polluted soil as the soil
around hyper accumulators is locally enriched in heavy
metals relative to soil without hyperaccumulators.
&: See references in recent reviews from 2010 (9) and 2012 (10) and 11-15 for later published
studies.
Reference list to supplementary table.
1. Iason G.R., Lennon J.J., Pakeman R.J., Thoss V., Beaton J.K., Sim D.A., Elston D.A. 2005 Does
chemical composition of individual Scots pine trees determine the biodiversity of their associated
ground vegetation? Ecol Lett 8364-369.
2. Pakeman et al 2006, Pakeman J.R., Beaton J.B., Thoss V., Lennon J.J., Campbell D.C., White D.,
Iason R.G. 2006 The extended phenotype of Scots pine Pinus sylvestris structures the understorey
assemblage. Ecography 29, 451-457
3. Ehlers B.K., Charpentier A., Grøndahl E. 2014 An allelopathic plant facilitates species richness in
the Mediterranean garrigue. J Ecol 102, 176-185
4. Tarayre M., Thompson J.D., Escarré J., Linhart Y.B. 1995 Intra-specific variation in the inhibitory
effects Thymus vulgaris (Labiatae) monoterpenes on seed germination. Oecologia 101, 110-118.
5. Linhart Y.B., Gauthier P., Keefover-Ring K., Thompson J.D. 2015 Variable phytotoxic effects of
Thymus vulgaris terpenes on associated species. Int J Plant Sci 176
6. Lankau R.A., Strauss S.Y. 2007 Mutual feedbacks maintain both genetic and species diversity in a
plant community. Science 317, 1561-1563.
7. Lankau R.A., Strauss S.Y. 2008 Community complexity drives patters of natural selection on a
chemical defense of Brassica Am Nat 171, 150-161.
8. Lankau R.A., Wheeler E., Bennett A.E., Strauss S.Y. 2011 Plant–soil feedbacks contribute to an
intransitive competitive network that promotes both genetic and species diversity. J Ecol 99, 176185.
9. Biedrycki ML., Bais HP. 2010 Kin recognition in plants: a mysterious behavior unsolved. J Exp Bot
61, 4123-4128.
10. Chen B.J.W., During H.J., Anten N.P.R 2012 Detect thy neighbor: Identity recognition at the
root level in plants. Plant Science 195, 157-167
11. File AL., Murphy GP., Dudley SA. 2012. Fitness consequences of plants growing with siblings:
reconciling kin selection, niche partitioning and competitive ability. Proc Roy Soc B 279, 209-218.
12. Fang S., Clark RT., Zheng Y., Iyer-Pascuzzi AS., Weitz JS., Kochian LV., Edelsbrunner H., Liao H.,
Benfey PN. Genotypic recognition and spatial responses by rice roots. 2013 PNAS 110, 2670-2675
13. Marler TE. 2013 Kin recognition alters root and whole plant growth of split-root Cycas
edentate seedlings. Hortscience 48, 1266-1269,
14. Semchenko M., Saar S., Lepik A. 2014 Plant root exudates mediate neighbour recognition and
trigger complex behavioural changes. New Phytol 204, 631-637.
15.Yang L., Callaway RM., Atwater DZ. 2015 Root contact responses and the positive realtionship
between intraspecfic diversity and ecosystem productivity. AOB Plants doi:10.1093/aobpla/plv053
16. Proffitt C.E., Chiasson R.L., Owens A.B., Edwards K.R., Travis S.E. 2005 Spartina alterniflora
genotype influences facilitation and suppression of high marsh species colonizing an early
successional salt marsh. J Ecol 93, 404-416
17. Crutsinger G.M., Strauss S.Y., Rudgers J.A. 2010 Genetic variation within a dominant shrub
species determines plant species colonization in a coastal dune ecosystem. Ecology 91, 1237-1243.
18. Michalet R., Xiao S., Touzard B., Smith D.S., Cavieres L.A., Callaway R.M., Whitham T.G. 2011
Phenotypic variation in nurse traits and community feedbacks define an alpine community. Ecol
Lett 14, 433-443.
19. Schöb C., Armas C., Guler M., Prieto I., Pugnaire F.I. 2013 Variability in functional traits
mediates plant interactions along stress gradients. J Ecol 101, 753-76
20. Liancourt P., Spence L.A., Song D.S., Lkhagva A., Sharkhuu A., Boldgiv
B., Helliker BR., Petratis PS., Casper BB. 2013 Plant response to climate change varies with
topography,interactions with neighbors, and ecotype. Ecology 94, 444–453.
21. Al Hayek P., Maalouf J.-P., Baumel A., Bou Dagher-Kharrat M., Médail F., Touzard B., Michalet
R. 2014 Differential effects of contrasting phenotypes of a foundation legume shrub drive plant–
plant interactions in a Mediterranean mountain. J Veg Science 26, 373-384
22. Al Hayek P., Maalouf J.-P., Touzard B., Michalet R. 2015 Disentangling the heritable and plastic
components of the competitive and facilitative effects of an alpine foundation species. J Ecol 103,
1172-1182
23.Davies C. 2011 Epiphyte diversity on Scottish aspen – a component of the extended phenotype.
PhD-thesis University of Edinburgh, Royal Botanic Garden Edinburgh & The James Hutton Institute,
Aberdeen.
24. Davies et al. 2014 Davies C., Ellis C.J., Iason G.R., Ennos R.A. 2014 Genotypic variation in a
foundation tree (Populus tremula L.) explains community structure of associated epiphytes. Biol
Lett 10,
25. Callaway R.M., Nadkarni N.M., Mahall B.E. 1991 Facilitation and interference of Quercus
douglasii on understory productivity in central California. Ecology 72, 1484–1499.
26. Pacheco-Villalobos & Hardtke 2012 Pacheco-Villalobos D., Hardtke, C.S. 2012 Natural genetic
variation of root system architecture from Arabidopsis to Brachypodium: towards adaptive value.
Phil Trans R Soc B 367, 1552-1558.
27Aschehoug ET., Callaway RM. 2014 Morphological variability in tree root architecture indirectly
affects coexistence among competitors in the understory. Ecology 95, 1731-1736
28. Cranston B.H., Callaway R.M., Monks A., Dickinson, K.J.M. 2012 Gender and abiotic stress
affect the community-scale intensity of facilitation and its costs. J Ecol 100, 915–922.
29. McNair MR. 2002 Within and between population genetic variatino for zink accumulation in
Arabidopsis halleri. New Phytol 155, 59-66
30. Taylor S.I., Macnair M.R. 2006 Within and between population variation for zinc and nickel
accumulation in two species of Thlaspi (Brassicaceae). New Phytol 169, 505-513
31. Koelbener A., Ramseier D., Suter M. 2008 Competition alters plant species response to nickel
and zinc. Plant and Soil 303, 241-251
32. Maestri E, Marmiroli M., Visioli G., Marmiroli N. 2010. Metal tolerance and hyperaccumulation:
Cost and trde-offs between traits and environment. Env Exp Bot 68, 1-13.
33. El Mehdawi A.F., Quinn C.F., E. P.-S. 2011 Selenium Hyperaccumulators Facilitate Seleniumtolerant neighbors via phytoenrichment and reduced Herbivory. Current Biol 21, 1440-1449.
34. El Mehdawi A.F., Quinn C.F., Pilon-Smits E.A. 2011 Effects of selenium hyperaccumulation on
plant-plant interactions: evidence for elemental allelopathy? New Phytol 191(1), 120-131