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Oecologia

, Volume 83, Issue 1, pp 38–46 | Cite as

On the stabilization of animal numbers. Problems of testing

3. What do we conclude from significant test results?
  • P. J. Den Boer
Original Papers

Summary

When testing census data of insect populations for regulation, and/or for overall density dependence in the course of numbers over years, certain conditions, which follow from the testing models, should be fulfilled. Even if the series of densities may be considered a piece of first-order Markov chain (a necessary condition) significant test results need not obviously point to regulation of numbers by dominant density-dependent processes. Such a case is presented by the pine looper population at “Hoge Veluwe” studied by Klomp. A drastic drop in density from 1952 to 1953, which takes 78–97% of the log-density range (LR) over all years, most probably wrongly causes significant test results. This is supported by some simulation experiments. Moreover, we cannot be sure that the population was sufficiently isolated, i.e. that dispersal of adults from surrounding populations did not importantly influence population numbers. Among 6 Panolis-populations studied by Schwerdtfeger during 17 years a single one scored significantly with all tests. This resulted, however, from such a drastic drop in density that it covered the entire log-density range (LR=9.39), which therefore is wider than in any of the other (non-significant) populations. Another Panolis-population that maintained itself during 60 years, and which also scored significantly, most probably was kept within limits by supplementation of very low densities with immigrants, on the one hand, and by restriction of high densities by defoliation caused by other species, on the other. It is discussed whether this can be considered “regulation”, or results from spreading of risk. It is concluded that the range stability of particular populations must be considered generally to be the result of stabilization by both internal and external processes among which both density-dependent and density-independent processes play a significant part, and from which the contribution of the density-dependent processes need not be separated. The most interesting aspect of the stabilization of animal numbers is its relationship with the expected survival time of the population.

Key words

Density dependence Regulation Closed populations Stabilization 

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References

  1. Andrewartha HG, Birch LC (1954) The distribution and abundance of animals. Chicago Univ Press, Chicago LondonGoogle Scholar
  2. Andrewartha HG, Birch LC (1984) The ecological web. More on the distribution and abundance of animals. Chicago Univ Press, Chicago LondonGoogle Scholar
  3. Baars MA, Van Dijk ThS (1984) Population dynamics of two carabid beetles at a Dutch heathland. II. Egg production and survival in relation to density. J Anim Ecol 53:389–400Google Scholar
  4. Bakker K (1971) Some general remarks on the concepts “population” and “regulation”. In: Den Boer PJ, Gradwell GR (eds) Dynamics of populations. PUDOC Wageningen, pp 565–567Google Scholar
  5. Bakker K (1980) A place on the planet. Some reflections on population ecology. Neth J Zool 30:151–160Google Scholar
  6. Begon M, Mortimer M (1981) Population ecology. Blackwell, OxfordGoogle Scholar
  7. Botterweg PF (1978) Moth behaviour and dispersal of the pine looper, Bupalus piniarius (L.) (Lepidoptera, Geometridae) Neth J Zool 28:341–464Google Scholar
  8. Dempster JP (1975) Animal population ecology. Acad Press, London New YorkGoogle Scholar
  9. Den Boer PJ (1968) Spreading of risk and the stabilization of animal numbers. Acta Biotheor Leiden XVIII:165–194Google Scholar
  10. Den Boer PJ (1981) On the survival of populations in a heterogeneous and variable environment. Oecologia 50:39–53Google Scholar
  11. Den Boer PJ (1985) Fluctuations of density and survival of carabid populations. Oecologia 67:322–330Google Scholar
  12. Den Boer PJ (1986a) Environmental heterogeneity and the survival of natural populations. Proc 3rd Eur Congress Ent A'dam, pp 345–356Google Scholar
  13. Den Boer PJ (1986b) Density dependence and the stabilization of animal numbers. 1. The winter moth. Oecologia 69:507–512Google Scholar
  14. Den Boer PJ (1986c) Facts, hypotheses and models on the part played by food in the dynamics of carabid populations. In: Den Boer PJ, Grüm L, Szyszko J (eds) Feeding behaviour and accessibility of food for carabid beetles. Report 5th meeting Eur Carab Stara Brda Pilska. Warsaw Agr Univ Press, pp 81–96Google Scholar
  15. Den Boer PJ (1986d) Population dynamics of two carabid beetles at a Dutch heathland. The significance of density-related egg production. In: Den Boer PJ, Luff ML, Mossakowski D, Weber F (eds) Carabid beetles, their adaptations and dynamics. Gustav Fischer, Stuttgart New York, pp 361–370Google Scholar
  16. Den Boer PJ (1987) Density dependence and the stabilization of animal numbers. 2. The pine looper. Neth J Zool 37:220–237Google Scholar
  17. Den Boer PJ (1988) Density dependence and the stabilization of animal numbers. 3. The winter moth reconsidered. Oecologia 75:161–168Google Scholar
  18. Den Boer PJ (1990) Density limits and survival of local populations in 64 carabid species with different powers of dispersal. J Evol Biol 3:19–40Google Scholar
  19. Den Boer PJ, Reddingius J (1989) On the stabilization of animal numbers. Problems of testing. 2. Confrontation with data from the field. Oecologia 79:143–149Google Scholar
  20. Ehrlich PR, Ehrlich A (1982) Extinction. Causes and consequences of the disappearance of species. Victor Gollancz, LondonGoogle Scholar
  21. Hassell MP (1986) Detecting density dependence. Trends in Ecology and Evolution. TREE 1:90–93Google Scholar
  22. Hilborn R, Stearns SC (1982) On inference in ecology and evolutionary biology: The problem of multiple causes. Acta Biotheor (Leiden) 31:145–164Google Scholar
  23. Kaufman L, Mallory K (1986) (eds) The last extinction. MIT Press, Cambridge (Mass) LondonGoogle Scholar
  24. Kendall MG (1962) Rank correlation methods. Charles Griffin 3rd ed, LondonGoogle Scholar
  25. Klomp H (1958) Larval density and adult fecundity in a natural population of the pine looper (Bupalus piniarius L.). Arch Néerl Zool 13:319–334Google Scholar
  26. Klomp H (1966) The dynamics of a field population of the pine looper, Bupalus piniarius L. (Lep., Geom.). Adv Ecol Res 3:207–305Google Scholar
  27. Nicholson AJ (1933) The balance of animal populations. J Anim Ecol 2 [S]:132–178Google Scholar
  28. Nicholson AJ (1954) An outline of the dynamics of animal populations. Austr J Zool II:9–65Google Scholar
  29. Nicholson AJ (1955) Density governed reaction, the counterpart of selection in evolution. Cold Spring Harb Symp Quant Biol XX:288–293Google Scholar
  30. Nicholson AJ (1958) Dynamics of insect populations. A Rev Ent 3:107–136Google Scholar
  31. Nicholson AJ (1960) The role of population dynamics in natural selection. In: Sol Tax (ed) Evolution after Darwin, Vol I. Chicago Univ Press, Chicago, pp 477–521Google Scholar
  32. Pielou EC (1974) Population and community ecology. Principles and methods. Gordon & Breach, New York Paris LondonGoogle Scholar
  33. Pollard E, Lakhani KH, Rothery P (1987) The detection of density dependence from a series of annual censuses. Ecology 68:2046–2055Google Scholar
  34. Reddingius J (1971) Gambling for existence. A discussion of some theoretical problems in animal population ecology. Acta Biotheor XX [S] Leiden, pp 1–208Google Scholar
  35. Reddingius J, Den Boer PJ (1970) Simulation experiments illustrating stabilization of animal numbers by spreading of risk. Oecologia 5:240–284Google Scholar
  36. Reddingius J, Den Boer PJ (1989) On the stabilization of animal numbers. Problems of testing. 1. Power estimates and estimation errors. Oecologia 78:1–8Google Scholar
  37. Schwerdtfeger F (1941) Über die Ursachen des Massenwechsels der Insekten. Z Angew Ent 28:254–303Google Scholar
  38. Smith HS (1935) The role of biotic factors in the determination of population densities. J Econ Ent XXVIII:873–898Google Scholar
  39. Solomon ME (1949) The natural control of animal populations. J Anim Ecol XVIII:1–35Google Scholar
  40. Solomon ME (1964) Analysis of processes involved in the natural control of insects. Adv Ecol Res II:1–58Google Scholar
  41. Strong DR (1986) Density-vague population change. Trends in Ecology and Evolution. TREE 1:39–42Google Scholar
  42. Thompson WR (1939) Biological control and the theories of the interactions of populations. Parasitology 31:299–388Google Scholar
  43. Thompson WR (1956) The fundamental theory of natural and biological control: A Rev Ent 1:397–402Google Scholar
  44. Uvarov BP (1931) Insects and climate. Trans Ent Soc London 79:1–247Google Scholar
  45. Van der Eijk R (1987) Population dynamics of the Gyrinid beetle Gyrinus marinus Gyll. (Coleoptera) with special reference to its dispersal activities. Diss. WageningenGoogle Scholar
  46. Varley GC (1949) Population changes in German forest pests. J Anim Ecol 18:117–122Google Scholar
  47. Varley GC, Gradwell GR, Hassell MP (1973) Insect population ecology, an analytical approach. Blackwell, Oxford LondonGoogle Scholar
  48. Wilbert H (1971) Feedback control by competition. In: Den Boer PJ, Gradwell GR, Dynamics of populations. PUDOC, Wageningen, pp 174–188Google Scholar

Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • P. J. Den Boer
    • 1
  1. 1.Biological Station LUWWijsterThe Netherlands

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