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Scale-dependency is one of the well-known features of ecological boundaries. Unfortunately, there are relatively few case studies analysing boundaries of different scales. Moreover, properties of moving split window (MSW) technique, a method potentially suitable for examining boundaries at several spatial scales, are not fully understood. In this study, we used artificial data sets to test the capacities and limitations of the MSW method. We also applied field data from the Mecsek Mts (Hungary) (611 m a.s.l.) in order to reveal possible boundaries at different scales and to contribute to the knowledge on vegetation pattern of mountain areas. We found that one should apply several window-widths when using MSW, since this is the only way to detect and differentiate between boundaries of different scales. Our study revealed the vegetation pattern of Mt Tubes: there is a series of continuously intergrading mesic communities on the northern slope, while the southern slope is occupied by a mosaic of different xeric communities. In this pattern, boundaries of two different scales have been identified. We conclude that MSW could effectively be used in similar mountain regions to analyse herb layer vegetation patterns and boundaries.
Moderating effects of trees on the environment in their immediate proximity are considered an important force in structuring plant communities, especially in harsh environments. In the semi-arid regions of the middle Carpathian Basin, such facilitative influences are expected to become crucial for the survival of several plant species, given the current warming and drying tendencies. We used 20 × 20 m plots to analyze whether grassland species adapted to mesic conditions penetrate forest patches, where they are able to survive. Using transects and the moving split window analysis, we also investigated how far the positive effects of the forest patches extend into grasslands, and whether this enables the existence of a steppe community that cannot tolerate extreme dry conditions and unfavorable soils. We found that beside forest-related species, forest patches hosted large numbers of grassland-related species. Among them, plants of closed steppe grasslands were the most numerous, which usually cannot tolerate the harsh conditions of open sandy grasslands, and are often confined to areas with better water and soil conditions. Our results showed that there is a 5–8 m wide closed steppe zone around the forest patches. Some species that are not able to survive in open xeric sandy grasslands are restricted to this zone. Unfortunately, while considerable attention is paid to the research, protection and restoration of sandy grasslands, forest patches are usually neglected. Our results emphasize that the establishment of individual trees and groups of trees should be actively promoted, because they have considerable nature conservation benefits by supporing closed steppe species.
Assessing habitat naturalness belongs to the most current issues in conservation biology. It has been recognized that plants are able to indicate the naturalness of their habitat. Thus, species may be given relative naturalness indicator values (i.e. scores on an ordinal scale), reflecting their different tolerances against habitat degradation. In the present study, our first goal was to test whether relative naturalness indicator values are able to reveal known differences in naturalness levels. Our second purpose was to compare four different methodological approaches in order to identify which is the most reliable when analyzing habitat naturalness. We compared near-natural and degraded plots on the bases of (1) unweighted plot means, (2) plot medians, (3) unweighted naturalness indicator value populations, and (4) frequency-weighted naturalness indicator value populations. We found that relative naturalness indicator values performed well in differentiating among near-natural and degraded vegetation. Unweighted mean indicator values were the most reliable, but frequency-weighted indicator value populations were nearly as efficient as unweighted means. We conclude that relative naturalness indicator values provide a simple but reliable tool for estimating habitat deterioration.
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