Vegetation mapping of Žumberak – Samoborsko gorje Nature Park, Croatia, using Landsat 7 and field data

A vegetation map of @umberak – Samoborsko gorje Nature Park with a minimum mapping unit of 2.25 ha (22500m2) was created during 2003. ALandsat ETM+ satellite image (acquired in the year 2000) and the results of field sampling were combined as mapping method. Given the constraints of the minimum mapping unit chosen, 17 classes were identified in the field and designated to corresponding polygons created by the classification of satellite image. Thirteen classes were plant communities or their combinations, while remaining four denoted various types of land cover (coniferous plantations, mixed rural landscapes, settlements and quarries). In the overall area of the Nature Park (344 km2), the most frequent type of cover was Lamio orvalae – Fagetum forest (38.4%of total area), while the most frequent non-forest community was Bromo – Plantaginetum mediae (7.9%). According to this research, as much as 77.3%of Park area is covered with forest, which is a significant increase compared to the old data of 61 % of forests. Analyses of mapped polygons showed that almost a quarter of all polygons has an area equal to, or just little bigger than the minimum mapping unit, while more than three quarters of all polygons have their area smaller or equal to 9 ha (corresponds to 300 x 300 meters square). Such an extreme mosaic landscape structure in conjunction with the constant depopulation of Park area causes further natural forestation of park and hence decreases in biodiversity. The overall accuracy of map was 65%, forest vegetation being mapped with higher accuracy (70%) than non-forest vegetation (61%)