Fine-scale pattern of the boundary zones in alkaline grassland communities

Abstract

We investigated the pattern of boundary types in alkaline grassland communities in Hungary. We used moving split window boundary analysis with dissimilarity functions, usually applied to detect ecotones and landscape boundaries at a coarse scale. The results were compared with those of correspondence analysis and clustering methods for the same data set, as well as with the local frequency distributions of populations along the studied transects. The MSW technique, usually applied in boundary and transition zone detection, was effective at a fine scale as well. The visible boundaries and transition zones were detectable with this method in most cases, but only sharp and narrow boundaries were verified with ordination and classification. If the changes are gradual in microtopography, then it is possible to detect transition zones between the vegetation patches. These types of transition zones can be considered as ecoclines. Despite the gentle microtopographical gradient, a marked border was detected between the Artemisio-Festucetum pseudovinae and the Achilleo-Festucetum pseudovinae communities. However, neither MSW did indicate boundary zone nor multivariate methods could distinguish sharply between these two communities. The small patches of the Artemisio-Festucetum pseudovinae association appear transitional between the adjacent communities in species composition along both transects. These patches cannot be considered as representing a distinct community type, and thus should be considered as ecotones