Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Density dependence explains tree species abundance and diversity in tropical forests


The recurrent patterns in the commonness and rarity of species in ecological communities—the relative species abundance—have puzzled ecologists for more than half a century1,2. Here we show that the framework of the current neutral theory in ecology3,4,5,6,7,8,9,10 can easily be generalized to incorporate symmetric density dependence11,12,13,14. We can calculate precisely the strength of the rare-species advantage that is needed to explain a given RSA distribution. Previously, we demonstrated that a mechanism of dispersal limitation also fits RSA data well3,4. Here we compare fits of the dispersal and density-dependence mechanisms for empirical RSA data on tree species in six New and Old World tropical forests and show that both mechanisms offer sufficient and independent explanations. We suggest that RSA data cannot by themselves be used to discriminate among these explanations of RSA patterns15—empirical studies will be required to determine whether RSA patterns are due to one or the other mechanism, or to some combination of both.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Figure 1: Fits of density-dependent symmetric model (red line) and dispersal-limitation model 3 (blue circles) to the tree species abundance data from the BCI, Yasuni, Pasoh, Lambir, Korup and Sinharaja plots, for trees ≥10 cm in stem diameter at breast height (see Table 1).
Figure 2: Test of the equivalence of the dispersal limitation model and the density-dependent symmetric model.
Figure 3: Plot of n derived from equation (1) versus n for the six data sets of tropical trees.


  1. Fisher, R. A., Corbet, A. S. & Williams, C. B. The relation between the number of species and the number of individuals in a random sample of an animal population. J. Anim. Ecol. 12, 42–58 (1943)

    Article  Google Scholar 

  2. Preston, F. W. The commonness and rarity of species. Ecology 29, 254–283 (1948)

    Article  Google Scholar 

  3. Volkov, I., Banavar, J. R., Hubbell, S. P. & Maritan, A. Neutral theory and relative species abundance in ecology. Nature 424, 1035–1037 (2003)

    Article  ADS  CAS  Google Scholar 

  4. Hubbell, S. P. The Unified Neutral Theory of Biodiversity and Biogeography (Princeton Univ. New Jersey, 2001)

    Google Scholar 

  5. Bell, G. The distribution of abundance in neutral communities. Am. Nat. 155, 606–617 (2000)

    Article  Google Scholar 

  6. McKane, A., Alonso, D. & Solé, R. V. Mean-field stochastic theory for species-rich assembled communities. Phys. Rev. E 62, 8466–8484 (2000)

    Article  ADS  CAS  Google Scholar 

  7. Bell, G. Neutral macroecology. Science 293, 2413–2418 (2001)

    Article  ADS  CAS  Google Scholar 

  8. Vallade, M. & Houchmandzadeh, B. Analytical solution of a neutral model of biodiversity. Phys. Rev. E 68, 061902 (2003)

    Article  ADS  CAS  Google Scholar 

  9. Houchmandzadeh, B. & Vallade, M. Clustering in neutral ecology. Phys. Rev. E 68, 061912 (2003)

    Article  ADS  CAS  Google Scholar 

  10. Alonso, D. & McKane, A. J. Sampling Hubbell's neutral theory of biodiversity. Ecol. Lett. 7, 911–914 (2004)

    Article  Google Scholar 

  11. Janzen, D. H. Herbivores and the number of tree species in tropical forest. Am. Nat. 104, 501–528 (1970)

    Article  Google Scholar 

  12. Connell, J. H. in Dynamics of Populations (eds Den Boer, P. J. & Gradwell, G. R.) 298–312 (Centre for Agricultural Publishing and Documentation, Wageningen, The Netherlands, 1971)

    Google Scholar 

  13. Chesson, P. L. & Warner, R. R. Environmental variability promotes coexistence in lottery competitive systems. Am. Nat. 117, 923–943 (1981)

    Article  MathSciNet  Google Scholar 

  14. Chesson, P. A need for niches? Trends Ecol. Evol. 6, 26–28 (1991)

    Article  CAS  Google Scholar 

  15. Etienne, R. S. & Olff, H. A novel genealogical approach to neutral biodiversity theory. Ecol. Lett. 7, 170–175 (2004)

    Article  Google Scholar 

  16. Morley, R. J. Origin and Evolution of Tropical Rainforests Ch. 5 (Wiley, New York, 2000)

    Google Scholar 

  17. Augspurger, C. K. Seedling survival of tropical tree species: interactions of dispersal distance, light gaps, and pathogens. Ecology 65, 1705–1712 (1984)

    Article  Google Scholar 

  18. Hubbell, S. P., Condit, R. & Foster, R. B. Presence and absence of density dependence in a neotropical tree community. Trans. R. Soc. Lond. 330, 269–281 (1990)

    Article  Google Scholar 

  19. Gilbert, G. S., Hubbell, S. P. & Foster, R. B. Density and distance-to-adult effects of a canker disease of trees in a moist tropical forest. Oecologia 98, 100–108 (1994)

    Article  ADS  CAS  Google Scholar 

  20. Condit, R., Hubbell, S. P. & Foster, R. B. Density dependence in two understory tree species in a neotropical forest. Ecology 75, 671–680 (1994)

    Article  Google Scholar 

  21. Harms, K. E., Wright, S. L., Calderón, O., Hernández, A. & Herre, E. A. Pervasive density-dependent recruitment enhances seedling diversity in a tropical forest. Nature 404, 493–495 (2000)

    Article  ADS  CAS  Google Scholar 

  22. Wright, S. J. Plant diversity in tropical forests: a review of mechanisms of species coexistence. Oecologia 130, 1–14 (2002)

    Article  ADS  Google Scholar 

  23. Etienne, R. S. A new sampling formula for neutral biodiversity. Ecol. Lett. 8, 253–260 (2005)

    Article  Google Scholar 

  24. Hilborn, R. & Mangel, M. The Ecological Detective: Confronting Models with Data Ch. 7 (Princeton Univ. Press, Princeton, New Jersey, 1997)

    Google Scholar 

Download references


We are indebted to D. Alonso and P. Chesson for advice. We gratefully acknowledge the work of the principal investigators and their field assistants for collecting the field data on the large plots of tropical forest. Specifically, we thank D. Thomas, G. Chuyong and D. Kenfack for the data from Korup National Park, Cameroon; R. Valencia, R. Foster and R. Condit for the data from Yasuni National Park, Ecuador; S. Davies, S. Tan, J. LaFrankie and P. Ashton for the data from Lambir Hills National Park, Sarawak; M. N. Supardi, P. Ashton and J. LaFrankie for the data from Pasoh Forest Reserve, peninsular Malaysia; and S.P.H.'s collaborators on the Barro Colorado Island plot, R. Foster and R. Condit. We also thank E. Losos for directing and coordinating the global programmes of the Center for Tropical Forest Science, which manages the plots, S. Loo for data management, and I. Rubinoff. This work was supported by NASA, by the NSF and the NSERC (Canada). The fieldwork has also received long-term support from the John D. and Catherine T. MacArthur Foundation, the Mellon Foundation, Earthwatch, Frank Levinson and the Celera Foundation, and other private foundations and individual donors.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Jayanth R. Banavar.

Ethics declarations

Competing interests

Reprints and permissions information is available at The authors declare no competing financial interests.

Supplementary information

Supplementary Notes

This file contains Supplementary Discussion and Supplementary Figure 1. (PDF 102 kb)

Supplementary Data*

This file includes additional data from the study. *This file was uploaded on 08 December 2005, as was erroneously omitted from original publication. (XLS 408 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Volkov, I., Banavar, J., He, F. et al. Density dependence explains tree species abundance and diversity in tropical forests. Nature 438, 658–661 (2005).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing