Control of a coypu Myocastor coypus population in northern Italy and management implications

Abstract

The effects of removal on the structure of a coypu population were investigated during a three‐year trapping program in the Val Campotto wetlands (northern Italy). The investigation was conducted on 267 specimens collected from March to December 1996. Winter severity index values indicated a sequence of cold winters, which may explain the unusual lack of individuals in the 0–4 months age class. Nevertheless, the demographic changes due to cold winters were counterbalanced by a high birth rate, the presence of pregnant females throughout the year and a low rate of embryo resorption (suggesting a high recruitment rate). Despite the intensive trapping campaign from 1994 to 1996 (8600 animals removed), no reduction of coypus was observed. Control campaigns and cold winters temporarily affected the sex ratio and age structure of the population, but did not limit coypu abundance. These results were compared with data collected during similar coypu control programs carried out in Italy and abroad.

Keywords:

• Myocastor coypus
• pest species
• population control
• demography
• management
• population structure

Acknowledgements

The study was carried out within the LIFE contract no. B4‐3200‐94‐778 funded by the European Community and Regione Emilia‐Romagna. We are grateful to Paolo Pini, director of the Consorzio della Bonifica Renana, and to his staff for their support of the project. We also thank Giovanni Vecchi, director of the Istituto Zooprofilattico Sperimentale (Bologna section), Valter Trocchi and Emilio Lenzo for their valuable contributions. Special thanks to Piero Genovesi, Dario Capizzi, Andrea Verardi and two anonymous referees for providing valuable criticisms on a previous draft of the manuscript.