Effects of food limitation, notonectid predation, and temperature on the population dynamics of Daphnia carinata

M. J. Barry*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

The relative contributions of invertebrate predation (Notonectidae: Anisops spp.), food limitation, and certain abiotic factors in driving the population dynamics of Daphnia carinata were studied for a two year period in a large farm dam in southern Victoria, Australia. Detailed measurements were made on the population densities of Daphnia and Anisops spp., the amount of food available, the nutritional status, and the size-specific fecundity of Daphnia. The density of the Daphnia population at the field site oscillated closely with water temperature. The amplitude of the population fluctuations varied seasonally, being much greater during the warmer months of the year and switching to fluctuations with low peaks when water temperature dropped below approximately 15 C. Anisops spp. densities were greatest in winter and declined during the spring of each year. Nymphs appeared in late spring and early summer and numerically dominated the population. During the warmer periods of the year, the daphnid population went through a series of rapid growth phases leading to over-exploitation of food resources and subsequent population collapses. Daphnia population densities were not correlated with Anisops numbers suggesting that predation was not a major regulatory factor during the warmer periods of the year. When water temperatures fell below ca. 15 C daphnid population densities remained low despite high food levels. During this period the impact of Anisops may have been greater. Two distinct phases were identified: a warm water period when food limitation was the main regulatory factor, and a cool water period when Anisops predation may have been the paramount factor. Low oxygen concentrations were associated with heavy rainfall in the spring and may have had a limiting effect on Daphnia for short periods. Daphnia may have had an important role in sustaining the Anisops population in the pond over each winter.

Original languageEnglish
Pages (from-to)545-562
Number of pages18
JournalInternationale Revue der Gesamten Hydrobiologie
Volume82
Issue number4
Publication statusPublished - 1997

Keywords

  • Daphnia carinata
  • Food limitation
  • Notonectid predation

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)

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