In this paper we analyse the demography of the mouflon colony inside the Orsiera -Rocciavré Natural Park. Starting fiom 1986, mouflon counts have been carried out, usually twice a year by the Park wardens. The population increased regularly from 115 animals in 1986 to 294 animais in 1994, with a mean animal growth rate of 12.5%. After 1994 the population decreased rapidly to 85 animals in 1998, with a mean animal decrease of 26.7%. The sex-ratio showed a constant tendency to be balanced throughout the study period, and ranged from 0.9 to 1.1. Natality ranged from 0.42 to 0.71 and was inversely correlated with the density in the previous year. In 1995 the Park started a program for the limitation of the mouflons inside the protected area. The animals actually culled were only 25, thus the control program can not be considered the only responsible for the decrease in the population after 1994. A density dependent effect on the fecundity of females may have contributed to the decrease. Wolf predation and climatic factors may also be responsible for this decline, although our data do not point out these effects. Our results are not consistent with the hypothesis of a detrimental effect of the mouflons on Alpine chamois in the study area.
Mouflon, Ovis (Orientalis) musimon, Alps, Protected area. Population dynamic, Density dependent effect.