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Hungarian oak (Quercus frainetto) has dominant or co-dominant role in many thermophilous deciduous forest communities in the Balkan Peninsula. However, recent field research in the north-western margin of its range has revealed that some stands have a pronounced mesophilous character, which was also supported by data from the literature. This paper aims to analyze this mesophilous community of Hungarian oak which is found in north-western Serbia, north-eastern Bosnia and Herzegovina (B&H) and eastern Croatia. Numerical analysis, which included classification and ordination of all 474 available relevés of Hungarian oak forests from the western and central Balkans, along with the 43 relevés of mesophilous forests of oak-hornbeam from B&H, have shown that 83 mesophilous Hungarian oak relevés are floristically and ecologically more similar to mesophilous forests of sessile oak-hornbeam (Erythronio-Carpinion) than to xero-thermophilous forests of Qeurcion confertae. The new association Carpino betuli-Quercetum frainetto ass. nova hoc loco was described, floristically and ecologically characterized and assigned to mesophilous oak-hornbeam forests of Erythronio-Carpinion. The study also discusses the syntaxonomical issues of Quercion confertae and its central association Quercetum frainetto-cerridis, considering the problem of the lack of good diagnostic species for both syntaxa, and introduces possible ways of dealing with these issues.

The paper describes two new mesophilous communities of oriental hornbeam (Carpinus orientalis) coppice from the northern Dinaric Alps in Bosnia and Herzegovina (B&H). While oriental hornbeam is mainly considered to be a part of thermophilous forests and scrub, numerical analysis of 103 relevés of C. orientalis dominated coppice from B&H has shown that two new, rather mesophilous, communities thrive on calcareous bedrock of NW B&H. They represent secondary successional stages of mesotermic forest vegetation in this region. Association Epimedio alpini-Carpinetum orientalis ass. nova hoc loco is related to Illyrian oak-hornbeam forests of Erythronio-Carpinion betuli, while Asplenio scolopendrii-Carpinetum orientalis ass. nova hoc loco is linked to Balkan submediterranean ravine forests of Ostryo-Tilion. Although these two associations were recorded only in the NW B&H, their distribution is potentially larger, as their source communities are relatively common throughout the Dinaric Alps, so the information about their distribution, vertical structure, and syndynamic relations could be very useful in a national scale forest management and nature conservation.

One promising area in understanding the responses of plants to ongoing global climate change is the adaptative effect of polyploidy. This work examines whether there is a coupling between the distribution of cytotypes and their biogeographical niche, and how different niches will affect their potential range. The study uses a range of techniques including flow cytometry, gradient and niche analysis, as well as distribution modelling. In addition, climatic, edaphic and habitat data was used to analyse environmental patterns and potential ranges of cytotypes in the first wide-range study of Festuca amethystina—a mixed-ploidy mountain grass. The populations were found to be ploidy homogeneous and demonstrate a parapatric pattern of cytotype distribution. Potential contact zones have been identified. The tetraploids have a geographically broader distribution than diploids; they also tend to occur at lower altitudes and grow in more diverse climates, geological units and habitats. Moreover, tetraploids have a more extensive potential range, being six-fold larger than diploids. Montane pine forests were found to be a focal environment suitable for both cytotypes, which has a central place in the environmental space of the whole species. Our findings present polyploidy as a visible driver of geographical, ecological and adaptive variation within the species.

Due to wide range of different ecological conditions, variety of human influence and historical development of flora and vegetation, forest vegetation of Bosnia and Herzegovina is very heterogeneous, and, at the same time, very poorly investigated in terms of their composition, ecology, distribution and syntaxonomy (Redžic, 2007; Beus & Vojnikovic, 2012). This can be applied also to the Pre-Pannonian region of BiH which is potentially occupied mainly by zonal sessile oak - com mon hornbeam forests, submontane beech forests and azonal dry, more or less acidophilous sessile oak forests (Stefanovic et al., 1983). Although area of Tresnjik hill is very close to Banjaluka city center, its vegetation was uninvestigated until present. As this area is one of the potential Natura 2000 sites in BiH (Milanovic & Golob, 2015), its habitats and wild species are to be preserved in a favorable conservation state. To facilitate this, one of the main objectives of this paper was to investigate forest habitat types in Tresnjik area. The other, not less important objective was to continue with the study of BiH vegetation, in order to contribute in solving the above mentioned problems. The research area Tresnjik is located in the NW part of Starcevica masiff (Figure 1), just a few kilometers soth from the Banjaluka city center (Figure 2). The area is orographicaly and geologicaly heterogeneous with the predominance of the flysch bedrock. The climate is temperate with average annual temperatures of 11.0°C, and annual precipitation of 1024 mm. All 55 releves collected in the field were made using the standard Central European phytosociological method (Braun-Blanquet, 1964). After analysis of the collected releves, 48 releves were synthetized and presented in two phytosociological tables. Classification was done according to floristic and ecological simmilarirties between releves, without the use of numerical classification methods. Total of seven floristically and ecologically well defined types were distinguished, and classified in two groups: • Group of beech habitat types (Table 1) 1. Habitat type Athyrium filix-femina-Fagus sylvatica (pure beech forests) 2. Habitat type Fagus sylvatica-Tilia tomentosa (forests of beech and silver lime) 3. Habitat type Quercus petraea-Tilia tomentosa (degradation of the former type with the domination of silver lime) • Group of sessile oak habitat types (Table 2) 1. Habitat type Quercus petraea-Carpinus betulus (zonal forest of sessile oak and common hornbeam) 2. Habitat type Vaccinium myrtillus-Quercus petraea (acidophilous sessile oak forests) 3. Habitat type Carpinus orientalis-Quercus petraea (thermophilous sessile oak forests) 4. Habitat type Fraxinus ornus-Carpinus orientalis (oriental hornbeam – mana ash scrub) Habitat types dominated by beech are ecologicaly and physiognomicaly quite similar, they are mainly found on the northern exposures with very steep slopes, but on deeper and nutrients richer soils. Sessile oak group on the other hand occurs on the milder slopes, but ecologicaly it is represented with three types: mesophilous one, found on deeper soils on predominantly carbonate bedrock, acidophilous type on acidic soils on flysch, and thermophilous type on shallow, rocky soils on dolomites or limestone. In this type there is also secondary succession stage of oriental hornbeam-mana ash scrub. Both groups are characterized by presence of relict species: Ruscus hypoglossum, Ruscus aculeatus (absent only from the most mesophilous beech type) and Ilex aquifolium. There is also great frequency of Rubus hirtus which abundance is in direct proportion with the level of stand degradation. It can be concluded that area of Tresnjik has relatively high diversity of forest vegetation (seven types on relatively small area). Also, results pointed out several problems in the phytosociology science in BiH that need to be adressed in the future: floristic composition, ecology, distribution, syntaxonomy and nomenclature of the main part of forest communities.

The paper deals with the floristic and ecological diversity of the riparian forest and scrub communitiesof the Sutjeska National Park in SE Bosnia and Herzegovina. Watercourses of the NP are represented bymontane to submontane small rivers and creeks with fast-flowing water and frequent strong but shortfloods. This caused specific types of riverine forest vegetation to develop along their banks. Classificationand ordination methods of numerical analysis were applied on 42 relevés sampled in the field. Theclassification has revealed five ecologically interpretable relevé groups: (1) willow scrub of Salix eleagnosand S. caprea on fertile fine grained deposits; (2) forests of Alnus glutinosa and Salix alba also onfiner deposits; (3) narrow strips of Alnus glutinosa along the low banks of smaller streams; (4) narrowstrips of Alnus glutinosa along the steep banks of wider streams; (5) thermo-mesophilous scrub of Salixeleagnos and Ostrya carpinifolia on gravel beds. All five groups are floristically and ecologically welldistinguished. While groups 1 and 3 are similar to already described communities from Central Europe(Salicetum eleagno-purpureae and Stellario nemorum-Alnetum glutinosae, respectivelly), groups 4 and5 most probably present, up to date, undescribed associations. Group 2 is rather floristically and ecologicallyheterogeneous, and as such possess transitional character (between Salicion albae and Alnionincanae alliances). Ordination revealed ecological gradient from nutrient rich (groups 1 and 2) to lessnutrient rich communities (groups 4 and 5).