# Developing a GIS Model for Identifying Bear Corridors with Open-Source Data: The Romanian Context
## 4 Discussion  
The modelling of GIS data by implementing the spatial analysis model proposed for obtaining the ecological corridor network using open-source databases with medium to low resolution (DEM with a resolution of 25 m) imposes subjectivity from the point of view of the precision of the digital mapping of the obtained result. The implementation of the proposed model at the local and small regional scale can deliver final results with a much higher precision if the free and open-source databases are replaced with databases obtained through direct measurements in the field or indirectly through UAV techniques. The most favorable range in which the brown bear moves is between 500 and 1500 m and corresponds to the floor of deciduous and mixed forests, comprised of beech, sessile oak, and orchards, which are a special source of food in the autumn period [43] when the bear has the last opportunity to accumulate the fat necessary for winter survival. In winter, the bear population begins to climb towards the coniferous forests at higher altitudes, which offer the opportunity to find a safe and quiet shelter so that winter sleep is not disturbed. At the beginning of spring, after the bear leaves the den, it moves to low altitudes, even below 500 m, to the places where plant vegetation occurs more quickly [44], approaching towns and causing damage to households [45]. The barrier effect imposed by the communication routes raises problems in identifying the optimal routes for the bears' movement. The transport network, both road and rail, is connected, so the identification of a continuous travel route is impossible to model due to the delimitation of the land islands inside the connected areas; thus, the analysis is carried out only inside an island waiting to be connected with the neighboring ones. To solve these problems, hypothetical ecological corridors of the bears' movement and crossing of the barriers imposed by the communication road infrastructure were created (Figure 8). The generation of such corridors was achieved by eliminating the restrictions related to the distance from the communication paths by identifying the areas belonging to the communication paths that overlap with forested areas and/or Natura 2000 areas [39]. Green bridges, or wildlife overpasses, play a vital role in enabling safe passage for bears across highways. These structures, which are intended to replicate natural habitats, are positioned strategically to coincide with important bear circulation routes based on corridor analysis. Proper maintenance and the addition of fencing, which guides animals toward approved crossing locations, further increase their efficacy. These actions assist the long-term sustainability of bear populations by reducing conflicts between wildlife and vehicles and maintaining the natural connection of corridors. Because in Romania there are four elements of green bridge type infrastructure, it was decided that the validation of the results obtained as a result of the finalization of the spatial analysis model should be conducted taking into account their location. Thus, in the case of two of these, the first located on the section of the A1 Deva-Lugoj highway between Holdea and Ohaba, the total overlap of the simulated route with the designed and built green bridge is identified. This 100% validation results from the fact that the green bridge was designed in such a way as to unite two bodies of forest resulting from the fragmentation of a single body as a result of the construction of the highway route, thus validating the fact that the choice of the area as a means of crossing the barriers imposed by the communication paths of the surfaces that overlap the forests can be used successfully in building the types of GIS model for the spatial analysis proposed.