European Journal of Wildlife Research

, Volume 56, Issue 3, pp 421–433 | Cite as

A monitoring program for Patagonian foxes based on power analysis

  • Alejandro Travaini
  • Alejandro Rodríguez
  • Diego Procopio
  • Sonia C. Zapata
  • Juan I. Zanón
  • Rolando Martínez-Peck
Original Paper


Culpeo fox (Pseudalopex culpaeus) and gray fox (Pseudalopex griseus) are heavily culled in Patagonia. Fox populations seem to persist thanks to spatial refuges from which hunted areas are repopulated, following a source–sink dynamics. Sustainable use of Patagonian foxes warrants the design of a monitoring program in nature reserves and areas subjected to predator control. During 7 years, we used visitation indices to bait stations in a national park and neighboring sheep ranches of southern Argentina. We operated bait stations during three consecutive nights and calculated seven indices of relative abundance. For each fox species, we compared the power of different monitoring designs and scenarios that combined visitation indices, effort (number of bait station lines and survey frequency) while controlling for type I error, and magnitude of population change during a given period. We looked at the combinations that produced high power (β ≤ 0.24). The operation of bait stations during several nights markedly increased statistical power. Index 7 (recording visits 72 h after activation) exhibited the lowest variation and improved expected power to detect a population trend. Both fox species could be monitored simultaneously, with power >0.76 in the short term (5 years), activating 24 bait station lines. We conclude that monitoring programs for culpeo fox and gray fox based on bait stations are able to detect marked declines but are less useful to reliably detect moderate increases in abundance, especially in sheep ranches.


Argentina Bait stations Culpeo fox Gray fox Population management Sustainable use 


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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Alejandro Travaini
    • 1
  • Alejandro Rodríguez
    • 2
  • Diego Procopio
    • 1
  • Sonia C. Zapata
    • 1
  • Juan I. Zanón
    • 1
  • Rolando Martínez-Peck
    • 1
  1. 1.Centro de Investigaciones de Puerto DeseadoUniversidad Nacional de la Patagonia Austral, CONICETPuerto DeseadoArgentina
  2. 2.Department of Conservation BiologyEstación Biológica de Doñana, CSICSevillaSpain

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