Effects of livestock and non-native mouflon on use of high-elevation pastures by Alpine chamois

Interspecific interference among livestock, native and non-native large herbivores is a key management and conservation issue, and little is known about its dynamics and implications. We investigated whether native Alpine chamois (Rupicapra r. rupicapra) modify their spatial distribution when non-native mouflon Ovis orientalis musimon and livestock (domestic sheep Ovis aries, and domestic goats Capra hircus) inhabit the same areas in the Alpine meadows of Italian Eastern Alps. We walked 5 hiking trails (5.0±0.1km) at dawn, twice a month during summers 2007 and 2008. During these surveys, we located each group of free-ranging ungulates (chamois, mouflon, and livestock). We also estimated the quality of meadows, finding that forage availability increased linearly as the distance from rocks (i.e., chamois refuges) increased. We predicted that the linear distance between chamois groups and rocks would depend on the co-presence of livestock and mouflon groups. Our results showed that chamois were more likely to be observed in areas with low food availability, but safer (i.e., closer to the rocks), whenever the nearest livestock group was larger and closer, especially if the shepherd's dog was present. Avoidance of the best feeding patches by the wild species is presumably due to spatial interference (e.g. visual and acoustic disturbance) and/or predation risk perception caused by the presence of shepherd's dogs. Similarly, the larger was the nearest group of mouflon, the closer to rocks was located the chamois group. Interestingly, mouflon group vicinity induced chamois to move closer to rocks only if mouflon rams were within the group. This suggests that physical displacement of the smaller species (i.e. chamois) is likely to occur to avoid direct disturbance of larger mouflon rams. Our study clearly showed how a native herbivorous species adjusts its spatial distribution and decreases the likelihood of using areas with higher food availability when livestock and/or a non-native species co-occur.