). These interfaces are among the most diverse and dynamic biophysical habitats on earth, and are particularly sensitive to environmental changes ( Naiman and Decamps, 1997 ). In riparian areas, vegetation contributes to carbon storage, serves as wildlife habitat and ecological corridor, stabilizes streambank and provides shade, food and organic matter for stream and its biota ( Salemi et al., 2012 ). Riparianforests are therefore recognized for their ecological importance, and the understanding of their growth dynamics and its relation with environmental variability
This study was carried out in Hungary, in an old unmanaged riparian poplar-willow forest during the breeding seasons of 2014 and 2015. The occurrence of two invasive tree species, the green ash and boxelder, is significant in the study area, which influences negatively the populations of native riparian tree species in Central Europe. We studied Great-spotted Woodpecker nest sites in the presence of these invasive species. Throughout the study period, eight and twelve nesting cavity trees were mapped. Trees were recorded in 20-20 circular plots of 0.05 ha both for each mapped nest trees and random plots as well. Species, diameter at breast height and condition were recorded for each tree. Composition and diversity of nest site and random plots were compared. Distributions and preferences were calculated for nest tree use. Most of the recorded trees were invasive. Nest site plots had more native trees compared to random plots. Nest site showed higher diversity in terms of all three variables. Decayed and dead willow and white poplar hybrid trees were preferred for nesting. Diameter at breast height of nest trees was between 30-90 cm. Studies about cavity excavators in transformed habitats have high importance for nature conservation of riparian forests.
The aim of the study was to compare the dynamics of Cu, Mn, Ni, Sr and Zn release during decomposition of leaves of Black alder (native material), Norway maple, Red oak and European beech (exogenous material) in the area of headwater riparian forests along the upper course of the Kamienna Creek (Northern Poland). Litter bag method was used in the experiment. Initial materials differed in terms of their chemical composition. Cu, Mn, Ni, Sr and Zn contents were low in general, and in fact, even a few times lower than limit values for decomposition rate. Different trends in the dynamics of the leaf metal content during decomposition were observed in particular tree species despite the fact, that every materials were exposed in the same site. Release dynamics was strongly affected by the content of metals in initial materials and in topsoil. Accumulation of Cu, Mn and Zn was observed during decomposition of poorest in the elements maple leaves, as well as Ni in alder leaves and Sr in the leaves of maple, alder and oak. In beech leaves we observed intensive leaching of Ni, whereas downward trends in the Cu concentration of beech leaves, as well as Mn and Zn in beech and oak leaves, were related to weight loss of the leaves. In some cases, the dynamics of metal release displayed a more complicated two- or three-stage character (release of Ni from maple and oak leaves; Cu from maple leaves; Sr from alder, maple and oak leaves; and Zn from alder and maple leaves).
The very dense floodplain vegetation on the artificially confined floodplains results in decreased flood conveyance, thus increase in flood levels and flood hazard. Therefore, proper floodplain management is needed, which must be supported by vegetation assessment studies. The aims of the paper are to introduce the method and the results of riparian vegetation classification of a floodplain area along the Lower Tisza (Hungary) based on automatized acquisition of airborne LiDAR survey. In the study area 15x15 m large training plots (voxels) were selected, and the statistical parameters of their LiDAR point clouds were determined. Applying an automatized parameter selection and 10-fold cross-validation he most suitable decision tree was selected, and following a series of classification steps the training plots were classified. Based on the decision tree all the pixels of the entire study area were analysed and their vegetation types were determined. The classification was validated by field survey. On the studied floodplain area the accuracy of the classification was 83%.
R eferences de Azevedo, I.F.P., Nunes, Y.R.F., de Avila, M.A., da Silva, D.L., Fernandes, G.W. & Veloso, R.B., (2014). Phenology of riparian tree species in a transitional region in Southeastern Brazil. Brazilian Journal of Botany . 37(1), 47-59. Boakye, E.A., Gebrekirstos, A., N’da Hyppolite, D., Barnes, V.R., Kouamé, F.N., Kone, D., Porembski, S. and Bräuning, A., (2016). Influence of climatic factors on tree growth in riparianforests in the humid and dry savannas of the Volta basin, Ghana. Trees . 30(5), 1695-1709. Bongard, P.M. & Wyatt, G., (2010
skalný ( Bubo bubo ) na nížine [Eagle-owl ( Bubo bubo ) on the lowland]. Dravce a sovy 1(1): 16-17. [In Slovak] Zuna-Kratky T 2003: Hnízdění výra velkého ( Bubo bubo ) v nížinných lužních lesích v SV Rakousku [Nesting of eagle-owl ( Bubo bubo ) in lowlands of riparianforests in the north-east of Austria]. Crex 20: 41-47. [In Czech with English summary]
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