Réka Aszalós

Static and dynamic approaches to landscape heterogeneity in the Hungarian forest‐steppe zone

. This paper describes the successional status of the vegetation in a clear-felled dry oak woodland at the edge of the Hungarian forest-steppe zone on the basis of a vegetation map. Due to a varied geomorphology of the colline landscape several so-called landscape units can be distinguished. The patchwork on the vegetation map is evaluated using several, morphology-based attributes (static morphological indices) traditionally applied in landscape ecology. In the ca. 100 years that elapsed since forest clear-cut, xeric grassland species and steppe elements became more abundant and the former xeromesophilous vegetation – containing even some woodland components – is slowly turning into xeric grassland communities. The vegetation units mapped can be arranged into a hypothetical succession scheme in which successional distances (the number of steps between two stages) are determined. Based on the distances thus obtained, a new dynamic morphological index is introduced. This is applied to each landscape unit for the dynamic evaluation of successional vegetation, its results being compared with those obtained by static morphological indices.

Practical application of spatial ecosystem service models to aid decision support

Highlights • A structured protocol for adapting a spatial ecosystem service model to local contexts is proposed.• Decision context, the final users and uses of maps should drive the way the spatial ecosystem service models are structured.• Simply increasing spatial resolution is not sufficient to increase legitimacy and the ultimate utility of maps.• The type and level of stakeholders’ involvement is a determinant of spatial model usefulness.

Synergistic effects of the components of global change: Increased vegetation dynamics in open, forest-steppe grasslands driven by wildfires and year-to-year precipitation differences

Climate change and land use change are two major elements of human-induced global environmental change. In temperate grasslands and woodlands, increasing frequency of extreme weather events like droughts and increasing severity of wildfires has altered the structure and dynamics of vegetation. In this paper, we studied the impact of wildfires and the year-to-year differences in precipitation on species composition changes in semi-arid grasslands of a forest-steppe complex ecosystem which has been partially disturbed by wildfires. Particularly, we investigated both how long-term compositional dissimilarity changes and species richness are affected by year-to-year precipitation differences on burnt and unburnt areas. Study sites were located in central Hungary, in protected areas characterized by partially-burnt, juniper-poplar forest-steppe complexes of high biodiversity. Data were used from two long-term monitoring sites in the Kiskunság National Park, both characterized by the same habitat complex. We investigated the variation in species composition as a function of time using distance decay methodology. In each sampling area, compositional dissimilarity increased with the time elapsed between the sampling events, and species richness differences increased with increasing precipitation differences between consecutive years. We found that both the long-term compositional dissimilarity, and the year-to-year changes in species richness were higher in the burnt areas than in the unburnt ones. The long-term compositional dissimilarities were mostly caused by perennial species, while the year-to-year changes of species richness were driven by annual and biennial species. As the effect of the year-to-year variation in precipitation was more pronounced in the burnt areas, we conclude that canopy removal by wildfires and extreme inter-annual variability of precipitation, two components of global environmental change, act in a synergistic way. They enhance the effect of one another, resulting in greater long-term and year-to-year changes in the composition of grasslands.

First signs of old-growth structure and composition of an oak forest after four decades of abandonment

Abstract The lack of natural references of dry-mesic oak forests creates conceptual obstacles for their conservation and close-to-nature management in Central Europe. Single-tree inventory was used to investigate stand characteristics and old-growth attributes of a Quercus petraea (Matt.) Liebl. and Q. cerris L. dominated, 120-year-old stand in a Hungarian forest reserve, abandoned approximately 40 years ago. All individuals were recorded with diameter ≥ 5 cm on the 3 ha study site. Logs, stumps, saplings and seedlings were also surveyed. 582 woody stem/ha belonging to 14 species were measured with single-tree inventory. Basal area values showed the total dominance of oaks in the canopy layer (99%) as a legacy of the long-term human exploitation. In contrast, young individuals of oak species were almost missing, and Acer campestre L. dominated the lower layers, indicating the transitional nature of the stand. Diameter classes showed a marked bimodal distribution. Both the abandonment of the reserve and the precedent severe oak decline contributed to the relatively high amount of dead wood (46 m3/ha). Four decades of abandonment is rather short time interval to generate a diverse forest composition and structure in a mature dry-mesic oak forest. The dense regeneration and shrub layer and the upsurgence of admixing species indicate the shift towards the uneven-aged and compositionally more diverse old-growth oak forest state. Among the structural forest features the dead wood had similar values as old-growth forests. If the recent trend continues, the studied oak forest develops towards a mixed forest with significantly lower ratio of oak species.