Biology session

Defining vegetation regions reflecting areas of vegetation with characteristic vegetation complexes have great importance from both practical and theoretical aspect. Besides known remnants of natural vegetation these efforts also consider the potential vegetation of areas with human-transformed vegetation or those void of vegetation, i.e. the potential natural vegetation (PNV).

Traditional vegetation regions are based on experts’ estimations, utilizing personal experiences. Our aim is to assess the possibilities of defining vegetation regions through formalized, statistical approaches using multiple PNV (MPNV) estimations by Somodi et al (2017) and to implement these in a sample area.

We used the Bükk Mountains as a sample area, because its vegetation is remained in a relatively natural state, which allows for the verification of our approach. As our study is based on the MPNV estimations, – which are based on the Hungarian Actual Habitat Database (MÉTA), – we used the hexagons applied by the MÉTA project as spatial unit. After calculating the distance index based on Kendall’s paired correlation, we used the UPGMA hierarchical clustering method and Principal Coordinate Analysis (PCoA). We cut the dendrogram resulting from the classification at several levels , and we plotted the resulting groups on the PCoA plots.

We found the 11 and 15 group arrangement the best in representing the underlying patterns. The most apparent pattern on the dendrograms was a large homogenous vegetation complex typical for the inner block of the Bükk Mountains. This complex contains mesic forests and rocky grasslands. The ordination represents the landscape types of the Bükk Mountains in respect to vegetation: those dominated by mesic forests, others dominated by dry foothill-associated vegetation complexes, others by wetlands mainly. The latters further separated into lowland and upland wetlands dominated landscape types. We plotted the groups on map and compared to the vegetation map by Zólyomi (1989). The two maps were reasonably similar however we were able to present a more complex representation of the vegetation.

We conclude that vegetation regions can be flexibly and realistically defined based on MPNV. According to the observations regarding the relatively natural Bükk Mountains, this method may have an enhanced role at specifying the vegetation regions in areas where natural vegetation has been less preserved.