Optimizing presence-absence surveys for detecting population trends

Jonathan R. Rhodes, Andrew J. Tyre, Niclas Jonzén, Clive A. McAlpine, Hugh P. Possingham

Research output: Contribution to journalReview article

34 Citations (Scopus)

Abstract

Presence-absence surveys are a commonly used method for monitoring broad-scale changes in wildlife distributions. However, the lack of power of these surveys for detecting population trends is problematic for their application in wildlife management. Options for improving power include increasing the sampling effort or arbitrarily relaxing the type I error rate. We present an alternative, whereby targeted sampling of particular habitats in the landscape using information from a habitat model increases power. The advantage of this approach is that it does not require a trade-off with either cost or the Pr{type I error} to achieve greater power. We use a demographic model of koala (Phascolarctos cinereus) population dynamics and simulations of the monitoring process to estimate the power to detect a trend in occupancy for a range of strategies, thereby demonstrating that targeting particular habitat qualities can improve power substantially. If the objective is to detect a decline in occupancy, the optimal strategy is to sample high-quality habitats. Alternatively, if the objective is to detect an increase in occupancy, the optimal strategy is to sample intermediate-quality habitats. The strategies with the highest power remained the same under a range of parameter assumptions, although observation error had a strong influence on the optimal strategy. Our approach specifically applies to monitoring for detecting long-term trends in occupancy or abundance. This is a common and important monitoring objective for wildlife managers, and we provide guidelines for more effectively achieving it.

Original languageEnglish (US)
Pages (from-to)8-18
Number of pages11
JournalJournal of Wildlife Management
Volume70
Issue number1
DOIs
StatePublished - May 17 2006

Fingerprint

habitat quality
monitoring
habitats
wildlife
wildlife management
Phascolarctos cinereus
sampling
process monitoring
habitat
trade-off
targeting
population dynamics
managers
demographic statistics
population trend
cost
simulation
methodology

Keywords

  • Koala
  • Markov model
  • Monitoring
  • Observation error
  • Occupancy
  • Optimization
  • Population trends
  • Presence-absence surveys
  • Statistical power

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Nature and Landscape Conservation

Cite this

Optimizing presence-absence surveys for detecting population trends. / Rhodes, Jonathan R.; Tyre, Andrew J.; Jonzén, Niclas; McAlpine, Clive A.; Possingham, Hugh P.

In: Journal of Wildlife Management, Vol. 70, No. 1, 17.05.2006, p. 8-18.

Research output: Contribution to journalReview article

Rhodes, Jonathan R. ; Tyre, Andrew J. ; Jonzén, Niclas ; McAlpine, Clive A. ; Possingham, Hugh P. / Optimizing presence-absence surveys for detecting population trends. In: Journal of Wildlife Management. 2006 ; Vol. 70, No. 1. pp. 8-18.
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