Pavel Unar

• Landscape Research Institute

Deadwood is known to be an irreplaceable substrate for various groups of organisms but its importance for vascular plants is still unclear. To examine which deadwood characteristics promote its colonization by vascular plants and whether species can prefer this substrate to mineral soil (or vice versa), we used regression modeling and ordination me...

Deadwood is known to be an irreplaceable substrate for various groups of organisms but its importance for vascular plants is still unclear. To examine which deadwood characteristics promote its colonization by vascular plants and whether species can prefer this substrate to mineral soil (or vice versa), we used regression modelling and ordination m...

Temperate forest ecosystems, including old-growth fragments, are subject to increasing pressures, both from biotic and abiotic factors. Frequent disturbance events, rising mean annual temperatures and longer-lasting droughts are causing changes in tree species composition, probably shifting the altitudinal distribution of herbaceous species as well...

The diameter growth of a tree reflects the success of that tree in competition. We investigated patterns of Fagus sylvatica diameter growth in the Žofín Forest Dynamics Plot, which is part of Smithsonian's Forest Global Earth Observatory as a research plot representing European natural mixed temperate forests. We focused primarily on the spatial pa...

The presence of coarse woody debris in forests is an important naturalness criterion as well as a biodiversity indicator. Decaying logs provide habitat for many organisms including vascular plants. The aims of this study are to describe the colonization of decaying logs by vascular plants in a lowland alluvial forest and to assess the impact of fal...

European beech is one of the most important European trees, not only because of its expected role in the face of climate change, but also as a frequent species in forest reserves, national parks and the NATURA 2000 network. For such areas, naturalness and biodiversity conservation are significant issues, in which the presence of deadwood plays an i...

Fagus sylvatica (European beech) populations in Central Europe are currently expanding their dominance in many forest types. In this study we focused on the spatio-temporal dynamics of beech recruitment as a mechanism for successful expansion. Specifically we investigated: (1) the developmental trend of the tree community composition and spatial pa...

European beech (Fagus sylvatica) increases its dominance in various forest types in Central Europe. In this context we investigated a very exceptional process, in which beech have been partly outcompeted by sycamore maple (Acer pseudoplatanus) in unmanaged forest without severe disturbances. Main research questions were as follows: (i) How did the...

The main focus of this paper was the dynamics of Fraxinus angustifolia tree spatial patterns after the frequency of flooding events has markedly declined, especially as regards competition with Carpinus betulus and Acer campestre, the most rapidly expanding species in alluvial hardwood forests in Central Europe. The study was conducted in alluvial...

There are hundreds of scientific papers dealing with the issues of biodiversity and extinction debt in temperate forests, both of which are partly related to the absence of deadwood. Some studies have derived habitat thresholds for deadwood (according to species, size, spatial distribution) as baselines for management recommendations. But a majorit...

This article focuses on assessing the habitats characteristics of endangered Calamagrostis pseudophrag-mites in selected localities in the Czech Republic with different river engineering measures, which can potentially influence the occurrence of this species. Furthermore, we give some general recommendations for management practices based on our r...

The decline of Abies alba (fir) in natural fir–beech forests in Europe has fascinated scientists for over a century. During this period, Fagus sylvatica (beech) became the dominant species in this forest type. We hypothesised that (1) the success of beech over fir is significantly connected with the fact that beech suffers less than fir from the pr...

QuestionsWhat are the differences between the tree spatial patterns (TSP) of various recruit and mortality waves in alluvial hardwood forests and mountain fir–beech forests? Are there any statistically significant differences between the mean TSP of these forest types? Are these differences stable over time? LocationAlluvial floodplain forests at t...

Peat mining has a serious impact on the Pinus rotundata Link habitat. The possibility of sustaining a vital Pinus rotundata bog forest on undisturbed edges of mined peat bog was assessed. 28.7 ha of undisturbed edge of Borkovická blata peat bog were sampled by regular grid of circular sample plots. Data about tree layer, natural regeneration of woo...

Peat mining has a serious impact on the Pinus rotundata Link habitat. The possibility of sustaining a vital Pinus rotundata bog forest on undisturbed edges of mined peat bog was assessed. 28.7 ha of undisturbed edge of Borkovická blata peat bog were sampled by regular grid of circular sample plots. Data about tree layer, natural regeneration of woo...

The long-term development of stand characteristics and tree spatial patterns (TSP), their mutual relation, and linkage to site and tree species were studied in the Boubín primeval forest (protected since 1858). Surveys were carried out in 1851, 1961/1964, 1972, 1984/1989, 1996 and 2010 on one to six research plots sized 0.58–1.00 ha. To see how res...

Tree species composition of Central European alluvial hardwood forests has changed with the arrival of flood-intolerant and mesic species. Within this group of tree species, a dominant role is played by field maple (Acer campestre) and European hornbeam (Carpinus betulus). This study was performed in the Lanzhot natural forests at the confluence of...

Current knowledge of the within-site variability of major stand structural features in beech dominated natural forests is limited. Numerous studies have used just several small plots for characterizations of natural stands, but this may lead to generalizations based on unreliable results. This study shows how major stand structural features vary at...

Based on a map of potential natural vegetation (PNV), actual vegetation was studied in the Mramor locality (106.4 ha). A total of 188 relevés were examined using stratified random sampling. A comparison was made between trends in vegetation variability throughout the entire locality and variability within the defined PNV units. The stratification o...

Since the mid-1970's, the landscape around the confluence of the Morava and Dyje rivers has undergone substantial changes related to the drop of water table caused by water management measures undertaken on both ri- vers. Periodical spring floods are among the phenomena lost due to ameliorations. In this study, the reaction of forest ecosystems to...

The paper deals with the issue of the spontaneous development of Central-European floodplain forests. The research object was the Cahnov–Soutok National Nature Reserve situated on the confluence of Dyje R. and Morava R. in the Czecho–Slovak-Austrian borderland area. This locality has been left to spontaneous development since the beginning of the 1...