This paper deals with the forest vegetation of the lower part of the dolines in Mecsek Mts. (South Hungary). In order to char-acterize this vegetation type, samples were compared to the 6 plant communities occurring in the neighbourhood of the dolines. Considering the vegetation texture and species com-position, the vegetation of the dolines resembles mainly the extrazonal beechwoods (Helleboro odori-fagetum) and local ravine forests (Scutellario altissimae-Aceretum) that preserve several mountain, subatlantic relict species in this area. Our study revealed that the plant communities characteristic of the karst surface of Western Mecsek are arranged along a moisture and nutrient gradient. In this system, the habitat conditions of the dolines are similar to those of the beech forests and the lo-cal ravine forests, fresh and relatively rich in nutrients. In the karst, dominated by oak-hornbeam and beech forests, effects of the thermal inversion are the most spectacular where beech forests follow turkey oak-sessile oak forests and oak-hornbeam forests on the lower part of the doline slopes. The described vegetation type of these depressions is developed by edafic fac-tors; its identification as a separate association is not supported by the analyses.
30 April 2012 in Journal of Cave and Karst Studies
With the intensification of aquaculture technologies, the amount of feed input and waste material is increasing, creating potentially negative impacts on freshwater habitats receiving effluent from such systems. Changes in biodiversity of zooplankton communities is often used to assess the effects of such impacts. Rotifers are suitable for bioindication of water quality due to their fast reaction to environmental changes. We examined seasonal changes in the diversity of rotifer communities along a 3.5 km section of the biggest oxbow lake in the Tisza River basin, Hungary, that received inflow from an intensive tank-based aquaculture farm. We detected a species-rich rotifer community with 26 species. Using the Rényi one-parameter diversity index families, we found that biodiversity increased away from the point of inflow in spring, but after a summer transition period the situation became partially reversed during autumn. At the beginning of the study period, the nutrient-rich effluent strengthened the dominance of common species, which decreased but did not disappear in summer. In autumn, the extra nutrient input delayed the decline of the rotifer community at the point of effluent.
Microclimate and vegetation architecture are interdependent. Little information is available, however, about the fine-scale spatio-temporal relationship between the microclimate and herb layer of forest-steppe mosaics. In 2018 a three-season-long vegetation sampling and measurements of air temperature and air humidity were performed along 4 transects (44 m long each) in the herb layer with 89 dataloggers in the sandy region of Central Hungary, in a poplar grove and the surrounding open grassland. In order to improve data analysis, we introduced the use of a duration curve widely used in hydrology and proved to be useful in the processing of intensive climatic data. We analysed the effect of the direction and altitude of the solar irradiation and the edge effect on the microclimatic pattern. We also surveyed, seasonally, the spatial pattern of the exceedance rate for the vapour pressure deficit (VPD) in relation to the transect direction and to the edge of the grove. The exceedance rate for the VPD indicated considerable seasonal differences. The VPD exceedance rate indicates the stress effect for the vegetation. The moderating effect of the grove was small at 1.2 kPa VPD, but at 3.0 kPa—stronger stress—it was considerable. On the warmer side of the transects, mostly exposed at the south-eastern edge, the exceedance rate rose abruptly with distance from the edge compared to the gradual increase on the colder side. The cardinal and intercardinal directions as well as the altitude of the Sun all had influences on the moderating and shading effects of the grove. The southern edge was not always consistently the warmest. The distribution of the VPD values above the 3.0 kPa threshold varied within a seemingly homogeneous grassland, which highlights the importance of fine-scale sampling and analysis. This knowledge is valuable for assessing the dynamics and spatio-temporal patterns of abiotic factors and physiognomy in this type of ecosystem.
With the intensification of aquaculture, the structure and dynamics of aquatic ecosystems are highly affected. At the same time, for a pond fish farmer, one of the most important tasks is to establish and maintain stable and favourable zooplankton populations. In this paper, we assess the effects of different supplementary feed types on zooplankton communities in freshwater fishponds. In an outdoor, experimental fishpond system, carp individuals of 2+ years of age were stocked and fed with either a fishmeal-based diet (FF), a plant meal containing experimental feed (PF) or cereals (CT). To compare the diversity of the zooplankton communities, we used the Shannon diversity index, and to assess the effects of environmental factors and the feed ingredients, we applied canonical correspondence analysis. We described the dynamics of zooplankton communities, where the biodiversity of rotifera and Crustacean communities showed temporal differences. In order to examine the effects of feed ingredients, temporal clustering was applied. The different diets did not consistently alter the composition of zooplankton communities. Consequently, the plant meal containing experimental feed had no negative effect on the planktonic biodiversity, which makes it suitable as an alternative feed source for fishponds at the applied level.