engleski

pace use and activity patterns of introduced Barbary sheep (Ammotragus lervia) in Southern Dinarides, Croatia

The Barbary sheep (Ammotragus lervia) is a species of caprid (goat-antelope) native to Rocky Mountains of North Africa. During 2002 five Barbary sheep (three females and two males) of unknown origin have been illegally released in the southern Dinaric region (Mosor Mountain ; 1.339 m a.s.l.) of Croatia. The current population size is estimated at around 210 animals. Study area is also home to grey wolves, which regularly predate the Barbary sheep. Wild boars are occasionally recorded at the periphery ; otherwise no other large mammals occur in the area, except for domestic sheep and goat. Illegal introduction of Barbary sheep has caused much controversy between hunters and environmental community since first animals were released. Hunters perceive the introduced animals as attractive game species and potential source of income, while environmentalists stress possible negative effects of introduced alien species on native flora and fauna and call for application of existing laws that prescribes complete removal of the introduced animals. In order to better understand ecology of the Barbary sheep, especially its general activity, habitat selection, potential for further spatial expansion and interactions with wolves, we captured and tracked six animals (two females and four males aged 2-4 years) with the use of GPS-GSM collars (Vectronic Aerospace GmbH). GPS collars were set to record a position every full hour, 24-hours per day over one year and then automatically drop-off. One 4-year female was killed by wolves 11 days after capture (predation event occurred at night at 23:45), and one of the collars failed immediately after tagging. Other four animals cumulatively moved 1.63 km per day and their circadian activity has two pronounced peaks at morning and evening. Peak activity changed in accordance to seasonal dynamics of the photoperiod. Generally, the tracked animals moved mainly along the mountain ridges of Mt. Mosor and several times moved along entire range (approx. 25 km) in relatively short time (2-4 days). On the other hand, movements perpendicular to the main mountain range were short and usually stopped at the mountain foothills with higher vegetation cover and less extreme terrain. Monthly home-range size ranged from 0.6 to 17.0 km2 (mean: 5.9 km2). For one animal we were also able to estimate annual home-range size: 26.0 km2. Current data suggest that Barbary sheep in the study area are limited to the Mosor M. range and are unlikely to expand their range. This could be connected with characteristics of surrounding habitat, which makes them vulnerable to wolf predation, as well as with illegal hunting in the surrounding hunting grounds.

Barbary sheep ; GPS collars ; habitat selection ; spatial expansion

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