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In the whole Europe, semi-natural calcareous grasslands are in strong decline in extension and threatened by abandonment (Riecken et al. 2002) and these managed pastures, being very rich-species ecosystems and representing priority habitat for European Union (92/43/EEC Directive) are noteworthy of conservation (Pärtel et al. 1996, Sebastià et al. 2008). The study area is located in Central Italy at 1500m a.s.l. and it is characterized by calcareous substratum, Northern aspect and a slope of 15-20°. Inside it traditional pastoral activities are mowing at the end of June then grazing. In last decades these practices underwent a collapse and intermediate situations (only mowing) or abandonment occurred. In this study the results regarding long-term change due to management modification (mowing and grazing–data of 1982, mowing and abandonment–data of 2005) are compared for the comprehension of different disturbance regimes effects on floristic richness and ecological differentiation. Contrarily to Grime’s theory (1973), the highest species richness is not noted in intermediately disturbed grassland, but in abandoned pasture ; in unmanaged situation an increase of Brachypodium genuense is evidenced. This provokes floristic (66% of whole flora) and soil parameters changes. The biggest shifts interest biomass and litter production, soil moisture, pH and nitrogen value. B. genuense has big dimension, strong vegetative capacity and high phytomass production that ensuing the formation of big litter amount, thus giving to this species a strong competitive ability. Early flowering strategy allows to avoid the period of top expansion of B. genuense and/or regenerative strategies (stolons first of all) consenting the competition with B. genuense for water and nutrients resources.

The aim of the study was to establish the main types of oak-hornbeam (Carpinus betulus and Quercus sp. div) forests on the Apennines, Balkan peninsula and southern Alps and their correlations with the main ecological and phytogeographical gradients in the region. Furthermore, the comparison with the major types recognized in the traditional expert-based classification was done. 1676 relevés of oak-hornbeam forests (alliances Erythronio-Carpinion, Carpinion moesiacum, Physospermo verticillati-Quercion cerris) from the area of the Apennines, Balkan peninsula and southern Alps were collected and entered in a Turboveg database. 508 relevés remained after stratification and were classified with a Modified Two Way Indicator Species Analysis, which resulted in four main clusters that are phytogeographically interpretable, such as (1) southern Apennines, (2) northern-central and central Apennines, (3) central-southern Balkan and (4) north-western Balkan and southern Alps, further divided into subclusters. Pignatti indicator values calculated for relevés of each subcluster were subjected to PCA in order to show the ecological relationships among subclusters, and the spectra of geo-elements were calculated to show the phytogeographical relationship between them. The diagnostic species combination was calculated by a fidelity measure (phi-coefficient) and presented in a synoptic table. Synsystematic classification of the elaborated groups is proposed.

The area of Učka Nature Park is comprised of the Učka massif and part of Ćićarija and is characterized by its specific position on the border of Continental and Mediterranean climatic influence. One of the main characteristics of this area are beech forests. A total of 121 vegetational relevés have been made following the standard Braun-Blanquet method. Numerical analyses of floristic composition were conducted and the relevés have been compared with the relevés of Aremonio-Fagion alliance from the surrounding area of Croatia and Slovenia. For description of ecological conditions Pignatti’s indicator values were used. The following plant associations of beech forests have been established: Seslerio autumnali-Fagetum M. Wraber ex Borhidi 1963, Ranunculo platanifolii- Fagetum Marinček et al. 1993 and Omphalodo-Fagetum (Tregubov 1957) Marinček et al. 1993. Seslerio autumnali-Fagetum is widely distributed across studied area and forms a continuous vegetation belt from 800 to 1150 m. Here it occurs on all aspects and slopes. On lower altitudes (700-800 m) it occurs in separate stands on mesophilous habitats surrounded by vegetation of Ostryo-Carpinion. A part of the relevés from this association differs from the typical stands with high proportion and coverage of the thermophilous species (Ostrya carpinifolia, Acer obtusatum, Sorbus aria, Tanacetum corymbosum and others). These stands usually occure on lower altitudes and they have developed by succession of ass. Seslerio-Ostryetum. In the southernmost part of the Učka Nature Park, on a small area specific stands of beech forest are developed surrounded by the thermophilous vegetation of Ostryo-Carpinion. These are the warmest habitats of beech forests in the studied area on deep and moisture soil. Such specific habitat features as well as proximity of Ostryo- Carpinion vegetation lead to interesting combination of thermophilous (Ostryo-Carpinion) and mesophilous (Lamio orvalae-Fagenion) species. Ass. Ranunculo platanifolii-Fagetum is developed in the highest parts of the Park. On Vojak it forms more or less a compact complex intermittent by some patches of ass. Seslerio-Fagetum on thermophilous microlocalities, while on other sites it occurs in isolated stands with more humid and cooler microclimate on higher altitudes within the ass. Seslerio-Fagetum. In general, this association occurs on the highest altitudes, largest terrain slopes and in coldest habitats. Stands of this association on investigated area are very poor in their floristic composition in comparison to the other areas where this association occurs. This can be explained by the fact that Učka is a mountain which rises directly from the sea and is subjected to the influence of the Mediterranean climate from almost all directions. Besides, the mountain massif above 1100 m is very small and there is not enough space which could create favourable conditions for the growth of higher number of high-mountain species.