Advertisement

Marine Biology

, Volume 93, Issue 2, pp 305–310 | Cite as

Demographic importance of ecological interactions: how much do statistics tell us?

  • J. R. Weinberg
  • H. Caswell
  • R. B. Whitlatch
Article

Abstract

Many investigators demonstrate the existence of intra- and interspecific interactions through rigorous statistical hypothesis testing. Statistical significance of an interaction, however, does not necessarily imply that it controls a species population size or distribution. Other analytical methods must be used to make these important determinations. This paper demonstrates one method, with an example, to quantify the demographic importance of statistically significant interactions. In our example, some of the statistically significant interactions with the polychaete Clymenella torquata (Leidy) have large impacts on the population growth rate of the bivalve Gemma gemma (Totten), while others do not. This demonstrates the necessity of distinguishing between statistical significance and demographic importance. In some cases, the demographic importance of the same interaction changes through time because of changes in the bivalve's life history. Interactions affecting juvenile bivalves often have a greater demographic importance than those affecting adults; but this is not always the case.

Keywords

Growth Rate Population Size Significant Interaction Life History Population Growth 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Literature cited

  1. Andrewartha, H. G. and L. C. Birch: The distribution and abundance of animals, 782 pp. Chicago: University of Chicago Press 1954Google Scholar
  2. Bradley, W. H. and P. Cooke: Living and ancient populations of the clam Gemma gemma in a Maine Coast tidal flat. U.S. Fish. Wildl. Serv., Fish. Bull. 58, 305–334 (1959)Google Scholar
  3. Caswell, H.: A general formula for the sensitivity of population growth rate to changes in life history parameters. Theor. Pop. Biol. 14, 215–230 (1978)Google Scholar
  4. Caswell, H., R. J. Naiman and R. Morin: Evaluating the consequences of reproduction in complex salmonid life cycles. Aquaculture 43, 123–134 (1984)Google Scholar
  5. Colwell, R. K.: Predictability, constancy, and contingency of periodic phenomena. Ecology 55, 1148–1153 (1974)Google Scholar
  6. DeKroon, H., A. Plaisier, J. van Groenendael and H. Caswell: Elasticity as a measure of the relative contribution of demographic parameters to population growth rate. Ecology (in press)Google Scholar
  7. Dobbs, F. C.: Community ecology of a shallow subtidal sandflat, with emphasis on sediment reworking by Clymenella torquata (Polychaeta: Maldanidae). M. S. thesis, 145 pp. Storrs: University of Connecticut 1981Google Scholar
  8. Dobbs, F. C. and R. B. Whitlatch: Aspects of deposit-feeding by the polychaete Clymenella torquata. Ophelia 21, 159–166 (1982)Google Scholar
  9. Gentile, J. H., S. M. Gentile, N. G. Hairston, Jr. and B. K. Sullivan: The use of life tables for evaluating the chronic toxicity of pollutants to Mysidopsis bahia. Hydrobiol. 93, 179–187 (1982)Google Scholar
  10. Green, R. H. and K. D. Hobson: Spatial and temporal variation in a temperate intertidal community, with special emphasis on Gemma gemma (Pelecypoda: Mollusca). Ecology 51, 999–1011 (1970)Google Scholar
  11. Mangum, C. P.: Activity patterns in metabolism and ecology of polychaetes. Comp. Biochem. Physiol. 11, 239–256 (1964)Google Scholar
  12. Rhoads, D. C. and D. J. Stanley: Biogenic graded bedding. J. Sed. Petrol. 35, 956–963 (1965)Google Scholar
  13. Sanders, H. L., E. M. Goudsmit, E. L. Mills and G. E. Hampson: A study of the intertidal fauna of Barnstable Harbor, Massachusetts. Limnol. Oceanogr. 7, 63–79 (1962)Google Scholar
  14. Sellmer, G. P.: Functional morphology and ecological life history of the gem clam Gemma gemma (Eulamellibranchia: Veneridae). Malacologia 5, 137–223 (1967)Google Scholar
  15. Weinberg, J. R.: Population ecology of the marine bivalve Gemma gemma in relation to its infaunal community. Ph.D. thesis, 121 pp. Storrs: University of Connecticut 1983Google Scholar
  16. Weinberg, J. R.: Interactions between functional groups in softsubstrata: do species differences matter? J. exp. mar. Biol. Ecol. 80, 11–28 (1984)Google Scholar
  17. Weinberg, J. R.: Factors regulating population dynamics of the marine bivalve Gemma gemma: intraspecific competition and salinity. Mar. Biol. 75, 173–182 (1985)Google Scholar
  18. Weinberg, J. R. and R. B. Whitlatch: Enhanced growth of a filter-feeding bivalve by a deposit-feeding polychaete by means of nutrient regeneration. J. mar. Res. 41, 557–569 (1983)Google Scholar

Copyright information

© Springer-Verlag 1986

Authors and Affiliations

  • J. R. Weinberg
    • 1
  • H. Caswell
    • 2
  • R. B. Whitlatch
    • 1
  1. 1.Department of Marine Sciences, Marine Sciences InstituteThe University of ConnecticutGrotonUSA
  2. 2.Woods Hole Oceanographic InstitutionWoods HoleUSA

Personalised recommendations