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Density dependence in an island population of silvereyes


McCallum, HI and Kikkawa, J and Catterall, C, Density dependence in an island population of silvereyes, Ecology Letters, 3, (2) pp. 95-100. ISSN 1461-023X (2000) [Refereed Article]

DOI: doi:10.1046/j.1461-0248.2000.00120.x


The population of silvereyes Zosterops lateralis chlorocephalus, on Heron Island, Great Barrier Reef has been monitored accurately since 1965. Between 1979 and 1993, the breeding success of all birds was determined by monitoring nests. The population fluctuated between 225 and 483 individuals. Four cyclones led to substantial mortality. As this data set is long-term, has little observation error, and is from an effectively closed population, it provides an unusual opportunity to examine density dependence in reproduction or mortality. Using a stochastic logistic model, we found clear evidence of density dependence in adult population size. Logistic regression suggested that fledgling survival decreased with the numbers of birds attempting to breed. There was also some suggestion that adult survival might be density dependent. The fitted stochastic logistic model predicts negligible risks of extinction for this population, in contrast to the predictions of a published population viability analysis. Whilst our statistical model including density dependence may provide better predictions of the 'usual' behaviour of a population than a population viability analysis, we suggest that caution should be exercised when statistically fitted models are used to predict the behaviour of the population at extremes, such as near extinction.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Terrestrial ecology
Objective Division:Environmental Management
Objective Group:Other environmental management
Objective Field:Other environmental management not elsewhere classified
UTAS Author:McCallum, HI (Professor Hamish McCallum)
ID Code:44409
Year Published:2000
Web of Science® Times Cited:28
Deposited By:Zoology
Deposited On:2007-05-21
Last Modified:2011-08-04

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