Beech Forest Species Research Articles

Low altitude Vaccinium myrtillus L. populations in the Eșelnița Valley (Danube Gorge, Carpathian Mountains, Romania)

The presence of certain species in habitats and at altitudes different from their usual ecological requirements has great biogeographic importance. Such a situation was identified in 2023 on the middle and lower course of Eșelnița Valley, a Danube tributary in the Carpathian Mountains in southwestern Romania. Thus, in Eșelnița Valley, we identified Vaccinium myrtillus and Calluna vulgaris species in beech forests at low altitudes. The lowest altitude with V. myrtillus in Eșelnița Valley was 198 m (approximately 5 km upstream from the Danube). On Eșelnița Valley, other species related to mountain areas are also present at low altitudes, favored by the narrow shape and the cooler microclimate of the valley.

Future forests and biodiversity: Effects of Douglas fir introduction into temperate beech forests on plant diversity

Introduction of drought-tolerant exotic tree species is seen as an important adaptation measure of forest management to climate change in Central Europe. Douglas fir (Pseudotsuga menziesii) is particularly favored in this context, because it is adapted to summer droughts due to the climate in its natural distribution range in temperate western North America and it is also fast-growing and the wood is readily marketable. In Germany, there are plans to grow Douglas fir on a large scale in mixed forests with other tree species on acidic soils. Potential ecological consequences have not yet been sufficiently scrutinized. Here, we analyze effects of Douglas fir introduction into forests of European beech (Fagus sylvatica), which would naturally predominate Central Europe’s forests. We analyzed vascular plant diversity and species composition of the ground vegetation in a gradient with increasing Douglas fir canopy fraction that ranged from pure beech (0% Douglas fir) via mixed stands (25%, 50%, 75% Douglas fir) to pure (100%) Douglas fir forest. Species richness, Shannon diversity, and Simpson diversity increased with increasing Douglas fir canopy fraction. However, this increase was primarily driven by an increase of nitrogen-tolerant disturbance indicators, whereas the share of forest species that were predominant in pure beech forests decreased. Beech forest species declined gradually with increasing Douglas fir canopy fraction, but these declining species were fewer than the number of species increasing due to Douglas fir introduction. Cover of ∼30% of species remained constant when Douglas fir was introduced. Strong changes in the ground vegetation were observed at Douglas fir canopy fractions > 40 – 50% and the original character of the ground vegetation was completely lost beyond a threshold of 75%. Therefore, we discourage from high Douglas fir proportions beyond these thresholds in production forests and from any introduction of Douglas fir where nature conservation is a priority.

太平洋型および日本海型ブナ林におけるブナ属の堅果食性小蛾類の多様性

本研究では，太平洋型ブナ林の高原山および日本海型ブナ林の水上において，(i) ブナ・イヌブナの落下前堅果を摂食する小蛾類幼虫の形態とミトコンドリア （mt） DNA の COI 領域の塩基配列に基づいて，両地域の小蛾類の多様性を明らかにすること，(ii) 各小蛾類種と堅果食痕の対応関係を明らかにすることを目的とした。高原山のブナ・イヌブナ，水上のブナの樹冠より直接落下前堅果を採取し，幼虫を捕獲した。そして，形態的特徴に基づいて幼虫のタイプ分けを行い，各タイプについて DNA の塩基配列を決定・比較した。その結果，太平洋型ブナ林では，ブナまたはイヌブナ堅果を摂食する小蛾類は 9 種おり，ハマキガ科が多く，優占種はブナヒメシンクイであった。一方，日本海型ブナ林の小蛾類は 2 種のみであり，両型のブナ林で小蛾類の多様性に違いがみられた。各小蛾類に種特異的な堅果食痕はみられず，食痕による種同定は困難と考えられた。また，太平洋型ブナ林では， 9 種のうち 7 種はブナ・イヌブナ両種の堅果を摂食しており，既往研究にある太平洋型ブナ林での高い虫害率は両樹種の堅果を摂食する種の存在と関係している可能性が示唆された。

Phytogeographical evidence for post‐glacial dispersal limitation of European beech forest species

The post‐glacial migration of European beech Fagus sylvatica has been addressed by many studies using either genetic or fossil data or a combination of both. In contrast to this, only little is known about the migration history of beech forest understorey species. In a review of phytosociological literature, we identified 110 plant species which are closely associated with beech forest. We divided the distribution range of European beech forests into 40 geographical regions, and the presence or absence of each species was recorded for each region. We compared overall species numbers per region and numbers of narrow‐range species (species present in <10 regions). A multiple regression model was used to test for the explanatory value of three potential diversity controls: range in elevation, soil type diversity, and distance to the nearest potential refuge area. A hierarchical cluster analysis of the narrow‐range species was performed.The frequency of range sizes shows a U‐shaped distribution, with 42 species occurring in <10 regions. The highest number of beech forest species is found in the southern Alps and adjacent regions, and species numbers decrease with increasing distance from these regions. With only narrow‐range species taken into consideration, secondary maxima are found in Spain, the southern Apennines, the Carpathians, and Greece. Distance to the nearest potential refuge area is the strongest predictor of beech forest species richness, while altitudinal range and soil type diversity had little or no predictive value. The clusters of narrow‐range species are in good concordance with the glacial refuge areas of beech and other temperate tree species as estimated in recent studies. These findings support the hypothesis that the distribution of many beech forest species is limited by post‐glacial dispersal rather than by their environmental requirements.

Comparison of plant species diversity with different plant communities in deciduous forests

Species diversity is one of the most important indices used for evaluating the sustainability of forest communities. This study aims to characterize the forest communities and to identify and compare the plant species diversity in the study area. For this purpose, 152 releves were sampled by a randomized-systematic method, using the Braun-Blanquet scale. Classification of the vegetation was conducted by the twinspan algorithm. Four communities, including Querco-Carpinetum betulii, Carpineto-Fagetum Oriental, Rusco-Fagetum Oriental and Fagetum Oriental were recognized. Species richness, Shannon, and Simpson indices were applied to quantify diversity of the different communities. Turkey test was used to investigate the differences in the species richness, diversity and evenness indices among the different communities. The results illustrate that Querco-Carpinetum betulii and Carpineto-Fagetum Oriental communities are significantly more diverse than Rusco-Fagetum Oriental and Fagetum Oriental communities. The spatial structure of the releves becomes more 'homogenous' and the dominance structure changes: the proportion of beech-forest species is gradually increasing. At the same time, the number of species per unit area decreases constantly, reaching eventually the value comparable to that recorded for hornbeam forest. Generally, species diversity is inversely correlated with the dominance of shade tolerant climax species.

Spatial smoothing techniques for the assessment of habitat suitability

Precise knowledge about factors influencing the habitat suitability of a certain species forms the basis for the implementation of effective programs to conserve biological diversity. Such knowledge is frequently gathered from studies relating abundance data to a set of influential variables in a regression setup. In particular, generalised linear models are used to analyse binary presence/absence data or counts of a certain species at locations within an observation area. However, one of the key assumptions of generalised linear models, the independence of observations is often violated in practice since the points at which the observations are collected are spatially aligned. In this paper, we describe a general framework for semiparametric spatial generalised linear models that allows for the routine analysis of non-normal spatially aligned regression data. The approach is utilised for the analysis of a data set of synthetic bird species in beech forests, revealing that ignorance of spatial dependence actually may lead to false conclusions in a number of situations.

Distribution and response of rats Rattus rattus, R. exulans to seedfall in New Zealand beech forests

Ship Rats Rattus rattus were much more abundant in Silver Beech-dominated Nothofagus menziesii forest in the Hollyford Valley than in Red Beech-dominated Nothofagus fusca forest of the Eglinton Valley, northern Fiordland National Park, in 1974?78. The Hollyford also supported a small population of Kiore (Pacific Rat) R. exulans, but no Norway Rats R. norvegicus. A moderate beech seedfall in 1976 was followed by a short-lived, six to seven fold increase in a relative index of abundance of Ship Rats in both valleys. This increase, not matched by Kiore, showed up more clearly in long lines of Fenn traps set for Stoats Mustela erminea than in standard rodent snap-trap lines. Analysis of 122 carcases showed a significant upward shift in age structure of Ship Rats after the seedfall, consistent with overwinter breeding. Conservation management programmes already aiming to protect threatened species in beech forests from post-seedfall irruptions of Stoats might need to be extended to include Ship Rats. Elsewhere in New Zealand, Ship Rats were much more abundant in mixed podocarp-hardwood forests than in pure beech or pine forests.

Effects on beech forest species of experimentally enhanced nitrogen deposition

Three and nine times the current nitrogen deposition in southern Sweden (60 and 180 kg ha -1 year -1 , ammonium nitrate) was applied to two beech stands in Scania, south Sweden, to study effects on cover and biomass of the field-layer vegetation. The study demonstrates that this application had rather small effects on field-layer species in the sites studied. The species composition was unaltered during the 5-year experiment. In one site the vegetation was also in other aspects relatively little changed apart from Impatiens parviflora that increased in cover. In the second site, cover and biomass were reduced for half of the common species ( Anemone nemorosa, Maianthemum bifolium, Oxalis acetosella, Poa nemoralis, Viola rivinianalreichenbachiana ) and no species increased. Species increasing in retrospective studies, probably because of the enhanced nitrogen deposition, have not changed in the present study ( Rubus idaeus, Stellaria nemorum ). Plausible explanations for the negative effects on the vegetation are the acidification of the soil solution due to excess nitrogen in relation to other nutrients, nutrient imbalance in the plants and the decreasing mycorrhizal infection.

Species response curves of macrofungi along a mull/mor gradient in Swedish beech forests

A graphical method of analyzing the spatial pattern of macrofungal species in beech forests is described. Species response curves are investigated both from the qualitative (presence/absence) and from the quantitative (log fruit-body number) variation of each species. The approach was applied to 49 macrofungal species, of which 34 were significantly related to certain pattern models. Macrofungi exhibit characteristic response curves along a one-dimensional mull/mor gradient. Also species with a relatively scarce occurrence have the potential to show significant patterns. Graphical tests of the qualitative and quantitative variation were used to provide a better description of the probability of a species to be present on certain sites.

Macrofungal flora of Swedish beech forest related to soil organic matter and acidity characteristics

The composition and edaphical differentiation of the beech forest mycoflora in Scania, south Sweden, was studied during 5 years, using 300 permanent sporophore observation plots. Considerable dissimilarities in species composition were found between topsoils of different acidity and organic matter properties. Less acid mull soils were particularly characterized by decomposer fungi. The frequency of mycorrhiza species increased sharply towards the most acid soils with more or less well-developed mor properties. The contribution of ‘exclusive’ beech forest species was usually a little below 20% of the frequency sum of all species. A conifer forest element became equally important in the most acid soils, in spite of a total lack of conifers in the stands. Most species attaining frequencies high enough for consideration exhibited a more or less distinct edaphical preference. The use of macrofungi as indicator organisms in environmental studies of soil acidification deserves future consideration.