engleski

Analysis of methods for wildlife monitoring on green bridges

Green bridges mitigate negative impact of roads/highways on wildlife populations. Their effectiveness is evaluated by various monitoring methods. Based on the 3‐year monitoring period of four green bridges on A1 motorway in Croatia, the effectiveness of three monitoring methods was compared: track‐pads, camera traps and active infrared (IR) trail monitoring system. The methods were evaluated in terms of their ability to detect different species and to give good estimation of the number of animal crossings. The accuracy of species detection by track‐pad method was influenced by granulometric composition of the track‐pad material, with the best results obtained when higher percentages of silt and clay were used. Regarding the species composition, monitoring by tracks underestimated the ratio of small canids, while camera traps underestimated the ratio of roe deer. Furt her, camera trap method underestimated the real number of animal crossings. On the contrary, active IR detectors recorded from 11 to 19 times more events than camera traps. However, circa 80% of IR events were not caused by wildllife crossings. Therefore, an algorithm for correction of the IR dataset was developed, in order to approximate the real number of crossings. In conclusion, presented results are valuable for future monitoring of wildlife crossings since they provide advantages and disadvantages of different monitoring methods.

green bridges; wildlife crossing monitoring; comparison of methods

nije evidentirano