Shrub Encroachment in a Wooded-Steppe Mosaic: Combining Gis Methods With Landscape Historical Analysis

Abstract

Shrub encroachment at the expense of grasslands is a world-wide phenomenon, which has considerable nature conservation consequences. On the southern slope of Mt Szársomlyó, one of Hungary's most unique nature reserves, shrubforest cover has been rapidly increasing in the past few decades. Our aim was to quantify this process and to give a comprehensive analysis of the landscape history of the area. Moreover, we compared Mt Szársomlyó to two nearby and similar mountains with a slightly different land-use history. It is almost certain that both shrubforests and grasslands were present on Mt Szársomlyó before human influence, although their original proportion is unknown. Southern slope was used as a pasture for centuries, maybe even for millennia. After grazing had come to an end during the 1970's, shrubforests began to expand rapidly: their cover increased from 9.83 % in 1964 to 21.7 % in 2005. In the case of the other two mountains, where grazing stopped earlier, forest cover is considerably higher than on Mt Szársomlyó, but this is partly due to the afforestation. It can be concluded that grazing of south-exposed rock swards should be regarded as a traditional land-use in the region. Further studies are needed to support nature conservation decisions.

The effects of different canopy covers on the herb layer in the forest-steppes of the Grazer Bergland (Eastern Alps, Austria)

“…However, typical species of the grassland patches continue to flourish (Erdős et al, 2013a). Moreover, in another forest-steppe (where grazing ceased considerably earlier), canopy cover increased to ca.…”

Vegetation history, recent dynamics and future prospects of a Hungarian sandy forest-steppe reserve: forest-grassland relations, tree species composition and size-class distribution

“…In extrazonal forest-steppes of the south facing slopes of mountain areas in the Pannonian biogeographical region, forest cover usually increases at the expense of grasslands rapidly (e.g., Centeri et al 2009, Erdős et al 2013c. In most of these cases, the treeless period ended a few decades ago when grazing ceased.…”

“…This, in most cases, means that woody species encroach into grasslands (e.g., Silva et al 2001, Brook andBowman 2006). The same process can be seen in some parts of the Pannonian biogeographical region, e.g., in loess grasslands (Somodi et al 2004) and rock swards (Erdős et al 2013c). Tree and shrub encroachment often results in a loss of biodiversity (Centeri et al 2009).…”

Does Shrub Encroachment Indicate Ecosystem Degradation? A Perspective Based on the Spatial Patterns of Woody Plants in a Temperate Savanna-Like Ecosystem of Inner Mongolia, China

“…Many studies clearly showed the indicative significance of shrub encroachment, which mainly depends on different factors, such as the type of ecosystem, past management practices, the current level of biodiversity, climate change, etc. [13,14]. In this region, shrubs have occupied the grassland habitat.…”

“…This difference in the perception of shrub encroachment could lead to completely different judgments of the states and transitions of shrub-encroached ecosystems, which would further affect decisions about their conservation and management [13]. An innovative study [14], combined with the landscape history and other environmental factors, quantified the process and indicative significance of shrub encroachment and provided us with new ideas. Therefore, more attention needs to be paid to ecosystem changes after shrub encroachment to clarify their ecological significance, especially the significance of the degree of shrub encroachment and changes in distribution patterns and structure.…”