Biological Invasions

, Volume 16, Issue 1, pp 167–175 | Cite as

Correlated recovery of five lizard populations following eradication of invasive mammals

  • Joanne M. MonksEmail author
  • Adrian Monks
  • David R. Towns
Original Paper


Many conservation decisions rely on the assumption that multiple populations will respond similarly to management. However, few attempts have been made to evaluate indicators of population trends (i.e. population indicator species). Eradication of introduced mammals from offshore islands is a commonly used management technique for conservation of native taxa in New Zealand. Pacific rats and rabbits were eradicated from Korapuki Island in 1986/1987 enabling population recovery of native species that had been suppressed by predation or competition. However, the degree to which species’ responses were correlated has not been evaluated. We investigated correlations among lizard population trends on Korapuki Island as a test of the population indicator species concept. Our dataset consisted of captures of the five resident lizard species (three skinks, two geckos) from biannual pitfall trapping over a 10 year period (1986–1995) immediately following rodent eradication. We used a Bayesian modelling approach to examine correlations in population trends (based on mean annual counts) between species. Population trends were positively correlated for all species pairs (substantively for 90 % of pairs) and we detected no negative correlations. Systematic searches for single lizard species may indicate correlated recovery of lizard populations following rodent eradication and provide a cost-effective alternative to traditional ‘whole community’ monitoring. Our findings support evidence-based use of the population indicator species concept in cases where a shared ecological driver can be identified.


Conservation management Herpetofauna Indicator species Invasive species Island Population trends 



We wish to thank Colin O’Donnell and Doug Armstrong for providing thoughtful discussions of the ideas presented, Chris Green, Ian McFadden and many others for field assistance, and Richard Earl for GIS support. This work was funded by the New Zealand Department of Conservation (DOC) as part of Science Investigations 3940 and 3236 and approved by the DOC Animal Ethics Committee (permit number 213). WinBUGS model code is available on request from the corresponding author.


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Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Joanne M. Monks
    • 1
    Email author
  • Adrian Monks
    • 2
  • David R. Towns
    • 3
  1. 1.Department of ConservationScience and Capability GroupChristchurchNew Zealand
  2. 2.Landcare ResearchDunedinNew Zealand
  3. 3.Department of ConservationScience and Capability GroupAucklandNew Zealand

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