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Knowledge of the vegetation and the monitoring of its changes in preserved areas is an essential part of effective conservation policy and management. The aim of this study was to assess the effectiveness of traditional methods of conservation of silver fir forests. The study analyses the changes in the structure and species composition of a temperate forest excluded from the commercial silvicultural management for 50 years, and since then protected as a nature reserve. The study is based on a comparative analysis of phytosociological reléves made on permanent plots in 1961, 1982, 1994 and 2011. PCA and ecological indicator values were analyzed, as well as characteristic species based on an indicator value (IndVal) index. Results revealed significant and dynamic changes in the forest structure and composition. The mixed coniferous-broadleaved forest with Abies alba and diverse ground flora, considered in the 1960s as valuable and worthy of conservation, was found to have been anthropogenically transformed and unstable. Significant reduction in the human impact was followed by spontaneous regeneration of oak–hornbeam forest. However, the directional process of changes in vegetation was modified by such silvicultural treatments as selective cutting of trees and gap creation, all intended for silver fir maintenance. The results show that Carpinus betulus effectively outcompeted Pinus sylvestris, Picea abies, Quercus robur and A. alba. Changes in the forest overstory and understory caused temporal changes in the habitat conditions reflected in changes in the ground vegetation composition. The proportion of light-demanding and oligotrophic species significantly decreased, while the contribution of species with a wide ecological amplitude, i.e. more shade-tolerant and nutrient-demanding – increased. The share of A. alba was reduced. Species defined in this study as most valuable, should be actively protected, or selection of conservation targets should be re-evaluated.
The studies of fallow lands were undertaken on the Przemyśl hills in the area of Cisowa locality which, till very recently, have been owned by a State Farm (PGR). The objective was to gain insight into the composition and diversification of plant communities on meadows, pastures and fields laid fallow, in context of habitat conditions prevailing after the use had ceased. The study utilised an old cadastral map showing the type of communities by category of use: meadows, pasture, and cultivated fields. The study material consisted of 180 relevés, obtained in the period 1998-2000 using the Braun-Blanquet method. By employing numerical classification, eight plant communities were distinguished, including only two of the association rank: Epilobio-Juncetum effusi, Arrhenatheretum elatioris. The analysis of Ellenberg’s habitat indices proved that all the communities belonged to the half-light vegetation group, occurring mostly on fresh soils, under intermediate moisture-content conditions, more rarely on moist soils which do not dry out. The soil reaction was most often neutral or slightly acidic, and in most of the soils the nitrogen content was in the intermediate range. The two principal trends in the succession of communities in the area, after its farming management has ceased, are: marked increase in species richness resulting from the expansion of species, and the process of overgrowing by woody vegetation.
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