Molinari-Jobin, A., Molinari, P., Breitenmoser-Würsten, C. & Breitenmoser, U. 2002: Significance of lynx Lynx lynx predation for roe deer Capreolus capreolus and chamois Rupicapra rupicapra mortality in the Swiss Jura Mountains. - - Wildl. Biol. 8: 109-115.
Prey class selection and kill rates by lynx Lynx lynx were studied in the Swiss Jura Mountains from March 1988 until May 1998 to evaluate the significance of lynx predation for roe deer Capreolus capreolus and chamois Rupicapra rupicapra. We found clear differences in the kill rates and prey class selection between lynx of different age, sex and breeding status. Male lynx killed more chamois than female lynx, and chamois was never found in kill series of subadult lynx. Family groups had the highest kill rate. They killed an ungulate every 5.0 days, compared to an average of 6.2-6.6 days for single lynx. During our 10-year study, the density of independent lynx was rather stable, ranging within 0.94-1.01 individuals/100 km². Based on the observed kill rates and the estimated lynx population structure we calculated that lynx killed 354 ± 13 roe deer and 87 ± 13 chamois annually in the 710 km² study area. The magnitude of lynx predation on roe deer and chamois was primarily shaped by the lynxpopulation structure. A decline in the number of resident male lynx reduced the number of chamois killed in the study area by 3 of the previous number due to the difference in prey selection of male and female lynx. There was a difference in the most frequently killed age and sex classes between roe deer and chamois: lynx killed more male chamois (39%) than females or fawns, whereas in roe deer, does (38%) were most often killed. By altering adult survival, lynx predation has a significant impact on prey population dynamics. Lynx killed a maximum of 9% of the roe deer and 11% of the chamois spring population. Considering the differences in the recruitment potential of the two prey species, lynx has a greater impact on chamois than on roe deer.
Key words: Capreolus capreolus, kill rate, Lynx lynx, predation, Rupicapra rupicapra
Anja Molinari-Jobin*, Institute of Zoology, University of Bern, Baltzerstrasse 3, CH-3012 Bern, Switzerland
Paolo Molinari, Via A Diaz 90, I-33018 Tarvisio, Italy - e-mail: p.molinari@progetto-lince-italia.it
Christine Breitenmoser-Würsten, KORA, Thunstrasse 31, CH-3074 Muri, Switzerland - e-mail: ch.breitenmoser@kora.ch
Urs Breitenmoser, Institute of Veterinary Virology, University of Bern, Länggassstrasse 122, CH-3012 Bern, Switzerland - e-mail: urs.breitenmoser@ivv.unibe.ch
*Present address: Rüti 62C, CH - 3855 Schwanden, Switzerland - e-mail: jobinmolinari@aol.com
Corresponding author: Anja Molinari-Jobin
Received 4 April 2001, accepted 24 August 2001
Associate Editor: Henryk Okarma