Community Ecology

, Volume 19, Issue 3, pp 281–288 | Cite as

Neighbourhood crowding severely limits seed offspring recruitment in a temperate mesic old-field meadow

  • A. Tracey
  • L. AarssenEmail author
Open Access


Testing the full impact of neighbourhood crowding within natural vegetation requires more than just effects incurred by established plants. It must also include measurements that take into account suppressive effects on the earliest plant life stages of resident individuals — seeds, their germination (emergence of radicles and cotyledons), and very young rooted seedlings. In this study, we explored the potential for these effects in a field experiment spanning three years, using a novel design for controlling granivory and small mammal herbivory. This allowed us to assess the limitations of natural crowding on seed recruitment success for non-resident species introduced into both natural and denuded neighbourhood plots within a temperate mesic old field meadow in eastern Ontario, Canada. Our results show that crowding by standing vegetation of resident species caused an overall reduction of seed recruitment success by more than 90%. These data provide strong inference that suppression resulting directly from near neighbour effects are likely to impose routinely intense natural selection within temperate mesic old field habitats like our study site. The consequences of this selection, in terms of traits promoting plant fitness under competition, are traditionally interpreted in terms of superior resource depletion/uptake, typically associated with greater growth accumulation and larger potential body size. We suggest, however, that these consequences are rare. Individuals of any species approach maximum potential body size only when near neighbour effects are relatively weak — not within crowded neighbourhoods. Recent studies suggest that severe neighbourhood crowding (where virtually all resident plants are forced to remain relatively small) selects instead for ‘reproductive economy’ — i.e., capacity to produce at least a few (or even at least one) offspring despite severe body size suppression, involving a relatively small minimum reproductive threshold size. Potential for additional component traits of reproductive economy are also suggested for investigation in future research.


Competition Fitness Neighbour effects Reproductive economy Seed addition Vegetation clearing 

Supplementary material

42974_2018_19030281_MOESM1_ESM.pdf (11 kb)
Supplementary material, approximately 11 KB.


  1. Aarssen, L.W. 1989. Competitive ability and species coexistence: a ‘plant’s eye’ view. Oikos 56:386–401.CrossRefGoogle Scholar
  2. Aarssen, L.W. 1992. Causes and consequences of variation in competitive ability in plant communities. J. Veg. Sci. 3:165–174.CrossRefGoogle Scholar
  3. Aarssen, L.W. 2005. Why don’t bigger plants have proportionately bigger seeds? Oikos 111:199–207.CrossRefGoogle Scholar
  4. Aarssen, L.W. 2008. Death without sex – the ‘problem of the small’ and selection for reproductive economy in flowering plants. Evol. Ecol. 22:279–298.CrossRefGoogle Scholar
  5. Aarssen, L.W. 2015. Body size and fitness in plants: revisiting the selection consequences of competition. Perspect. Plant Ecol. Evol. Syst. 17:236–242.CrossRefGoogle Scholar
  6. Aarssen, L.W. and G.A. Epp. 1990. Neighbour manipulations in natural vegetation: a review. J. Veg. Sci. 1:13–30.CrossRefGoogle Scholar
  7. Aarssen, L.W. and T. Keogh. 2002. Conundrums of competitive ability in plants: what to measure? Oikos 96:531–542.CrossRefGoogle Scholar
  8. Aschehoug, E.T., R. Brooker, D.Z. Atwater, J.L. Maron and R.M. Callaway. 2016. The mechanisms and consequences of interspecific competition among plants. Annu. Rev. Ecol, Evol. Syst. 47:263–281.CrossRefGoogle Scholar
  9. Brooker, R., Z. Kikvidze, G. Kustler, P. Liancourt and M. Seifan,. 2013. The concept and measurement of importance: a comment on Rees et al. 2012. J. Ecol. 101:1369–1378.Google Scholar
  10. Bullock, J. 2000. Gaps and seedling colonization. In: Fenner M (ed) Seeds: The Ecology of Regeneration in Plant Communities, 2nd ed. CABI Publishing, Wallingford, UK. pp. 375–396.CrossRefGoogle Scholar
  11. Burke M.J.W. and J.P Grime. 1996. An experimental study of plant community invasibility. Ecology 77:776–790.CrossRefGoogle Scholar
  12. Damgaard, C. and A. Fayolle.. 2010. Measuring the importance of competition: a new formulation of the problem. J. Ecol. 98:1–6.CrossRefGoogle Scholar
  13. Darwin, C. 1859. On the Origin of Species. Murray, London.Google Scholar
  14. Dombroskie, S.L., A.J. Tracey and L.W. Aarssen. 2016. Leafing intensity and the fruit size/number trade-off in woody angiosperms. J. Ecol. 104:1759–1767.CrossRefGoogle Scholar
  15. Fayolle, A., C. Violle and M.L. Navas. 2009. Differential impacts of plant interactions on herbaceous species recruitment: disentangling factors controlling emergence, survival and growth of seedlings. Oecologia 159:817–825.CrossRefGoogle Scholar
  16. Foster, B. 1999. Establishment, competition and the distribution of native grasses among Michigan old-fields. J. Ecol. 87:476–489CrossRefGoogle Scholar
  17. Gleason, H.A. and A. Cronquist. 1991. Manual of the Vascular Plants of North-eastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, N Y, USACrossRefGoogle Scholar
  18. Goldberg, D.E. 1996. Competitive ability: definition, contingency and correlated traits. Philos. Trans. R. Soc. Lond. B 351:1377–1385.CrossRefGoogle Scholar
  19. Goldberg, D.E. and A.M. Barton. 1992. Patterns and consequences of interspecific competition in natural communities: a review of field experiments with plants. Am. Nat. 139:771–801.CrossRefGoogle Scholar
  20. Gurevitch, J., L.L. Morrow, A. Wallace and J.S. Walsh. 1992. A meta-analysis of competition in field experiments. Am. Nat. 140:539–572.Google Scholar
  21. Grace, J. B. 1990. On the relationship between plant traits and competitive ability. In: Grace, J. B. and Tilman, D. (eds), Perspectives on Plant Competition. Academic Press, New York. pp. 51–65.Google Scholar
  22. Grime, J.P. 1979. Plant Strategies and Vegetation Processes. Wiley, New York.Google Scholar
  23. Harper, J.L. 1977. Population Biology of Plants. Academic Press, London.Google Scholar
  24. Hart, S.P., R.P. Freckleton and J.M. Levine. 2018. How to quantify competitive ability. J. Ecol. 106:1902–1909.CrossRefGoogle Scholar
  25. Jutila, H.M. and J.B. Grace. 2002. Effects of disturbance on germination and seedling establishment in a coastal prairie grassland: a test of the competitive release hypothesis. J. Ecol. 90:291–302.CrossRefGoogle Scholar
  26. Keddy, P.A. 1989. Competition. Chapman and Hall, London.CrossRefGoogle Scholar
  27. Kikvidze, Z. and R. Brooker. 2010. Towards a more exact definition of the importance of competition — a reply to Freckleton et al. (2009). J. Ecol. 98:719–724.CrossRefGoogle Scholar
  28. Kleijn, D. 2003. Can establishment characteristics explain the poor colonization success of late successional grassland species on ex-arable land? Restor. Ecol. 11:131–138.Google Scholar
  29. Knappova, J., M. Knapp and Z. Munzbergova. 2013. Spatiotemporal variation in contrasting effects of resident vegetation on establishment, growth and reproduction of dry grassland plants: Implications for seed addition experiments. PLoS ONE 8(6):e65879.CrossRefGoogle Scholar
  30. Miller, T. E. 1996. On quantifying the intensity of competition across gradients. Ecology 77:978–981.CrossRefGoogle Scholar
  31. Moles, A.T. and M. Westoby. 2004. What do seedlings die from and what are the implications for evolution of seed size? Oikos 106: 193–199.CrossRefGoogle Scholar
  32. Taylor, D.R. and L.W. Aarssen. 1990. Complex competitive relationships among genotypes of three perennial grasses: implications for species coexistence. Am. Nat. 136:305–327.CrossRefGoogle Scholar
  33. Thorpe, A.S., E.T. Aschehoug, D.Z. Atwater and R.M. Callaway. 2011. Interactions among plants and evolution. J. Ecol. 99:729–740.CrossRefGoogle Scholar
  34. Tracey, A.J. and L.W. Aarssen. 2014. Revising traditional theory on the link between plant body size and fitness under competition: evidence from old-field vegetation. Ecol. Evol. 4:959–967.CrossRefGoogle Scholar
  35. Tracey, A.J., and L.W. Aarssen. 2018. Resident species with larger size metrics do not recruit more offspring from the soil seed bank in old-field meadow vegetation. J. Ecol. (in press).Google Scholar
  36. Tracey, A.J., K.A. Stephens, B.S. Schamp and L.W. Aarssen. 2016. What does body size mean, from the “plant’s eye view”? Ecol. Evol. 6:7344–7351.Google Scholar
  37. Trinder, C.J., R.W. Brooker and D. Robinson. 2013. Plant ecology’s guilty little secret: understanding the dynamics of plant competition. Funct. Ecol. 27, Special Issue SI:918–929.CrossRefGoogle Scholar

Copyright information

© Akadémiai Kiadó, Budapest 2018

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  1. 1.Department of BiologyQueen’s UniversityKingstonCanada

Personalised recommendations