Phototraps as a Non-Invasive Method of Monitoring Otters (Lutra lutra): What can we Expect?

In the frame of the EU project LIFE III – NATURA, running for the 3rd year in northeastern part of Republic of Slovenia, a series of 5 – 10 passive infrared cameras is used for monitoring otters (Lutra lutra) in the area of Landscape Park Gori ko (390 km2). Our special attention is focused on main otter and watercourse corridor running through the area, all the way followed by the road and a new railway (finished 2001). Establishing and consequently mitigating the possible negative influence of railway on the otter population was the primary aim of camera monitoring. Simultaneously, classic method of monitoring otters is used, collecting spraints. The comparison between results planned and actual preliminary results shows, that most of the planned cameras’ purposes cannot be fulfilled, for instance distinction of individual animals, due to different objective reasons. On the other hand, some new interesting characteristics of population have been discovered, such as recording of otter family life, as well as unexpected threats to the population. Finally, on the basis of camera monitoring it is assumed that the density of otter population living in the area was overestimated at the beginning of the project, although the water network in the area is fully covered with otters all the time.