Spatial distribution assessment of invasive alien species Amorpha fruticosa L. by UAV-based on remote sensing in the Special Nature Reserve Obedska Bara, Serbia.

The Obedska Bara Special Nature Reserve is one of the oldest protected areas in the world, also enlisted as an Important Bird Area, Ramsar and UNESCO world heritage site. False indigo bush (Amorpha fruticosa L.) represents an invasive alien species which is significantly deteriorating the biodiversity of the Obedska Bara Special Nature Reserve in Serbia. Mapping of A. fruticosa, using an unmanned aerial vehicle and GIS tools, showed that in meadows, pastures, ponds and wetland areas, A. fruticosa covered 85 ha or 11% of the area. However, coverage was uneven, and the most overgrown areas were some meadows (up to 35%), while flooded areas and areas where human impact is significant, as on pastures, were not so affected (1-3%). The most susceptible parts were forest edges. Active management practices, such as cattle grazing and topsoil tarping, and occasional moving, gave positive effects in A. fruticosa, but also other invasive terrestrial plant species spreading control in the reserve. This has also been confirmed by the UAV survey and mapping, which has proven to be an effective method for A. fruticosa monitoring over large areas.