Are patterns of density dependence in the Global Population Dynamics Database driven by uncertainty about population abundance?
Article first published online: 21 OCT 2011
© 2011 Blackwell Publishing Ltd/CNRS
Volume 15, Issue 1, pages 17–23, January 2012
How to Cite
Knape, J. and de Valpine, P. (2012), Are patterns of density dependence in the Global Population Dynamics Database driven by uncertainty about population abundance?. Ecology Letters, 15: 17–23. doi: 10.1111/j.1461-0248.2011.01702.x
- Issue published online: 1 DEC 2011
- Article first published online: 21 OCT 2011
- Editor, Jean-Michel Gaillard Manuscript received 30 June 2011 First decision made 9 August 2011 Manuscript accepted 21 September 2011
- Density dependence;
- observation error;
- time series
Ecology Letters (2011) 14: 17–23
Density dependence in population growth rates is of immense importance to ecological theory and application, but is difficult to estimate. The Global Population Dynamics Database (GPDD), one of the largest collections of population time series available, has been extensively used to study cross-taxa patterns in density dependence. A major difficulty with assessing density dependence from time series is that uncertainty in population abundance estimates can cause strong bias in both tests and estimates of strength. We analyse 627 data sets in the GPDD using Gompertz population models and account for uncertainty via the Kalman filter. Results suggest that at least 45% of the time series display density dependence, but that it is weak and difficult to detect for a large fraction. When uncertainty is ignored, magnitude of and evidence for density dependence is strong, illustrating that uncertainty in abundance estimates qualitatively changes conclusions about density dependence drawn from the GPDD.