Letter | Published:

Density-dependent mortality and the latitudinal gradient in species diversity

Nature volume 417, pages 732735 (13 June 2002) | Download Citation

Subjects

Abstract

Ecologists have long postulated that density-dependent mortality maintains high tree diversity in the tropics1,2,3,4,5,6. If species experience greater mortality when abundant, then more rare species can persist1,2,7,8,9. Agents of density-dependent mortality (such as host-specific predators, and pathogens) may be more prevalent or have stronger effects in tropical forests, because they are not limited by climatic factors1,2,3,4,5. If so, decreasing density-dependent mortality with increasing latitude could partially explain the observed latitudinal gradient in tree diversity4,5,6. This hypothesis has never been tested with latitudinal data. Here we show that several temperate tree species experience density-dependent mortality between seed dispersal and seedling establishment. The proportion of species affected is equivalent to that in tropical forests6,10,11,12,13,14,15,16, failing to support the hypothesis that this mechanism is more prevalent at tropical latitudes. We further show that density-dependent mortality is misinterpreted in previous studies. Our results and evidence from other studies suggest that density-dependent mortality is important in many forests. Thus, unless the strength of density-dependent mortality varies with latitude, this mechanism is not likely to explain the high diversity of tropical forests.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    Herbivores and the number of tree species in tropical forests. Am. Nat. 104, 501–528 (1970)

  2. 2.

    in Dynamics of Populations (eds den Boer, P. J. & Gradwell, G. R.) 298–312 (Center for Agricultural Publication and Documentation, Wageningen, The Netherlands, 1971)

  3. 3.

    & Herbivory and plant defenses in tropical forests. Annu. Rev. Ecol. Syst. 27, 305–335 (1996)

  4. 4.

    On the causes of gradients in tropical tree diversity. J. Ecol. 87, 193–210 (1999)

  5. 5.

    Tropical Forest Ecology 190–195 (Oxford University Press, New York, 1999)

  6. 6.

    , , , & Pervasive density-dependent recruitment enhances seedling diversity in a tropical forest. Nature 404, 493–495 (2000)

  7. 7.

    & Ecology of seed dispersal. Annu. Rev. Ecol. Syst. 13, 201–228 (1982)

  8. 8.

    , , & Seed predation and the coexistence of tree species: Hubbell's models revisited. Oikos 44, 382–390 (1985)

  9. 9.

    & Herbivores and plant diversity. Am. Nat. 140, 243–260 (1992)

  10. 10.

    , & Compensatory recruitment, growth, and mortality as factors maintaining rain forest tree diversity. Ecol. Monogr. 54, 141–164 (1984)

  11. 11.

    , & Recruitment near conspecific adults and the maintenance of tree and shrub diversity in a neotropical forest. Am. Nat. 140, 261–286 (1992)

  12. 12.

    , , & Tree distribution pattern and fate of juveniles in a lowland tropical rain forest—implications for regeneration and maintenance of species diversity. Plant Ecol. 131, 155–171 (1997)

  13. 13.

    & Similar non-random processes maintain diversity in two tropical rainforests. Proc. R. Soc. Lond. B 266, 1445–1452 (1999)

  14. 14.

    & Species co-existence in an Australian subtropical rain forest: evidence for compensatory mortality. J. Ecol. 87, 316–329 (1999)

  15. 15.

    & Seedling density dependence promotes coexistence of Bornean rain forest trees. Ecology 80, 2006–2017 (1999)

  16. 16.

    , , & Strong density- and diversity-related effects help to maintain tree species diversity in a neotropical forest. Proc. Natl Acad. Sci. USA 94, 1252–1257 (1997)

  17. 17.

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

  18. 18.

    , & Density and distance to adult effects of a canker disease of trees in moist tropical forest. Oecologia 98, 100–108 (1994)

  19. 19.

    A test of the Janzen–Connell model with two common tree species in Amazonian forest. J. Trop. Ecol. 8, 529–536 (1997)

  20. 20.

    & Herbivory and plant species coexistence: community regulation by an outbreaking phytophagous insect. Ecol. Monogr. 70, 73–99 (2000)

  21. 21.

    & Soil pathogens and spatial patterns of seedling mortality in a temperate tree. Nature 404, 278–281 (2000)

  22. 22.

    , & Woody seedling dynamics in an east Texas floodplain forest. Ecol. Monogr. 59, 177–204 (1989)

  23. 23.

    , , , & Woody plant regeneration in four floodplain forests. Ecol. Monogr. 64, 345–367 (1994)

  24. 24.

    Diversity in tropical rain forests and coral reefs. Science 199, 1302–1310 (1978)

  25. 25.

    Seed predation and the coexistence of tree species in tropical forests. Oikos 35, 214–229 (1980)

  26. 26.

    Alternatives in parent–offspring relationships in plants. Oikos 45, 148–149 (1985)

  27. 27.

    , & Presence and absence of density dependence in a neotropical tree community. Phil. Trans. R. Soc. Lond. B 330, 269–281 (1990)

  28. 28.

    The Janzen–Connell model for tropical tree diversity: population implications and the importance of spatial scale. Am. Nat. 140, 526–530 (1992)

  29. 29.

    & Spacing dynamics of a tropical rain forest tree: evaluation of the Janzen–Connell model. Am. Nat. 124, 769–788 (1984)

  30. 30.

    , & Stages and spatial scales of recruitment limitation in southern Appalachian forests. Ecol. Monogr. 68, 213–235 (1998)

Download references

Acknowledgements

Funding was provided by Sigma Xi and National Science Foundation grants. We thank M. Dietze, K. Harms, I. Ibanez, S. Ladeau, J. Lynch, J. McLachlan, J. Mohan, A. Pringle and M. Rocca for discussion of data and comments on drafts of the manuscript. Support in the field was provided by R. Hille Ris Lambers and H. Passmore.

Author information

Author notes

    • Janneke Hille Ris Lambers
    •  & Brian Beckage

    Present addresses: Department of Ecology, Evolution, and Behavior, University of Minnesota, St Paul, Minnesota 55108, USA (J.H.R.L.); Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996, USA (B.B.).

Affiliations

  1. *Biology Department, Duke University, Durham, North Carolina 27708, USA

    • Janneke Hille Ris Lambers
    • , James S. Clark
    •  & Brian Beckage
  2. ‡Nicholas School of the Environment and Earth Sciences, Durham, North Carolina 27708, USA

    • James S. Clark

Authors

  1. Search for Janneke Hille Ris Lambers in:

  2. Search for James S. Clark in:

  3. Search for Brian Beckage in:

Competing interests

The authors declare that they have no competing financial interests

Corresponding author

Correspondence to Janneke Hille Ris Lambers.

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nature00809

Further reading

Comments

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.