Provide more small artificial breeding sites rather than fewer large sites

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Study locations

Key messages

  • One study evaluated the effects on mammals of providing more small artificial breeding sites rather than fewer larger sites. This study was in Spain.



  • Abundance (1 study): A replicated, controlled study in Spain found that smaller artificial warrens supported higher rabbit densities than did larger artificial warrens.


About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A replicated, controlled study in 2002–2005 of two grassland and scrubland plots at a site in Andalucia, Spain (Rouco et al. 2011) found that providing smaller artificial warrens for wild rabbits Oryctolagus cuniculus supported higher rabbit densities than did larger artificial warrens. Rabbit density was higher in small artificial warrens (4–13 rabbits/12 m2 plot) than it was in large artificial warrens (11–24 rabbits/48 m2 plot). Two plots (4 ha each, 2 km apart) were fenced to exclude terrestrial predators. Each plot had 18 artificial warrens, comprising 12 small and six large warrens. Warrens were skeletons of wooden pallets covered by earth and branches. Large warrens (48 m2) were the size of four small warrens (12 m2). In autumn 2002, five rabbits were released into each small warren, and 20 rabbits were released into each large warren. Rabbits were surveyed by live-trapping, three times, from November 2004 to May 2005.

    Study and other actions tested
Please cite as:

Littlewood, N.A., Rocha, R., Smith, R.K., Martin, P.A., Lockhart, S.L., Schoonover, R.F., Wilman, E., Bladon, A.J., Sainsbury, K.A., Pimm S. and Sutherland, W.J. (2020) Terrestrial Mammal Conservation: Global Evidence for the Effects of Interventions for terrestrial mammals excluding bats and primates. Synopses of Conservation Evidence Series. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

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Terrestrial Mammal Conservation

This Action forms part of the Action Synopsis:

Terrestrial Mammal Conservation
Terrestrial Mammal Conservation

Terrestrial Mammal Conservation - Published 2020

Terrestrial Mammal Conservation

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