Abstract

We searched for patterns supporting the hypothesis of compositional and functional linkage between forest floor nematode communities and dominant tree canopies, while controlling for some relevant soil and climate variables. Twenty-one forest sampling sites scattered throughout the South-Eastern Carpathian basin were selected under spruce, beech, and hornbeam-oak canopies. The relative contribution of forest canopy type to nematode assemblage differentiation was estimated through nematode taxonomic composition and feeding guild structure. The forest canopy type had a significant effect on nematode taxon/feeding guild composition and diversity at stand level. Several (diagnostic) nematode taxa and feeding guilds were positively associated with and accurately predicted the forest canopy types considered. Apart from the herbivorous nematodes, all the other trophic guilds were significantly related, in terms of their relative abundance, to the forest canopy type. Both nematode taxonomic and trophic diversity were significantly higher under beech canopy compared with its two counterparts. The highest total nematode beta diversity, either taxonomic or trophic, was attained between hornbeam- oak and spruce canopies. Nematode taxonomic and trophic beta diversity between forest canopy types were largely determined by taxon replacement and respectively, by a nested trophic structure. Overall, four concordant and two discordant patterns were revealed between nematode taxon and feeding guild composition with respect to overlying forest canopy, all underpinning the addressed ecological linkage. The present results bring evidence regarding the important contribution of the forest canopy, along with climatic variables, in driving the taxonomic and functional composition/diversity of nematode communities from the soil organic horizon.

Abstract

The Carpathians represent not only a European hotspot of plant diversity for both species richness and endemism, but also an important stepping-stone area in historical migrations between the flora of the Asian and European mountain systems and a starting point of postglacial recolonizations for many species. Yet, until recent years, phylogeographical studies for alpine or arctic-alpine plants were focused on the Alps, whereas peripheral mountain ranges, including the Carpathians, were either neglected or insufficiently sampled. In this study, we aimed to complement the Alpine phylogeographic structure of an emblematic high-alpine European endemic taxon, Eritrichium nanum, by focusing on the Carpathian range of the species. We sampled nine populations from the South-Eastern Carpathians and performed ITS1 sequencing and AFLP fingerprinting. In case of ITS1 region, all the populations, no matter of their geographic origin, presented the same ribotype. The AFLP analysis indicated that, within the Carpathians, the extant populations of E. nanum comprised two major allopatric lineages. One important result of the research was the discovery that the species' sole important genetic break was located in the Southern Carpathians, separating populations of the Retezat Mountains from all the others in the Carpathians.

Abstract

Abstract

Oligotrophic peat bogs reach the southern boundary of their European distribution area in the Romanian Carpathians. They shelter boreal species considered glacial relicts, surviving from the Würmian III period. Such areas (habitats) conserving relict species have major phytohistorical importance. They provide insights into the history of forest vegetation in the region and past climatic conditions. Based on floristic, phytocoenological and phytogeographical data, we propose to include two active raised bogs, namely “Calul de Piatră” and “Izvorul văii Șoimului” in the ROSCI0116 Molhașurile Căpățânei site of community interest. The inclusion of the two bogs in the ROSCI0116 Molhașurile Căpățânei protected area will increase the peat bog surface in the Apuseni Mountains and will be beneficial for the conservation of the wetland habitats and their typical flora, both very vulnerable to natural and anthropogenic disturbances. © 2022, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

Abstract

We investigated the floristic dissimilarities and their ecological drivers between three regional groups of Scots pine woodlands from mires dispersed along a latitudinal gradient in Eastern Europe. Phytosociological data regarding such woodland communities from the Eastern Carpathians (Romania) and lowlands of Poland and Latvia were collected from 47 published releves. In spite of the small number of good discriminant species, the relative positions of the three regional groups of communities in the bi-dimensional ordination space roughly matched their geographical separation along latitude and longitude. When the spatial autocorrelation was filtered out, the three regional groups of communities appeared partly overlapping in the two-dimensional ordination space, whose axes correlated with the occurrences of some species that are typical of either open or wooded bogs and, respectively, either hummocks or hollows. The total herb cover was negatively and significantly correlated with both the first partial ordination axis and total shrub cover. We concluded that the observed, small floristic dissimilarities were mainly induced by weak, small-scale gradients of autogenic successional development and groundwater level/microtopography. Our results do not support the distinction of a montane, Eastern Carpathian vicariant of the syntaxon Vaccinio uliginosi-Pinetum sylvestris from the lowlands of Central and Baltic Europe.

Abstract

Background Previous investigations carried out in ultramafic habitats emphasized the greater importance of site conditions over soil toxic metal content for vegetation composition. Very little is known about the floristic structure of the Southern Carpathian ultramafic grasslands and there is no information on the local environmental drivers of their composition and coenotic features. Here, we aim to fill these knowledge gaps by referring to similar phytocoenoses described in the Balkan Peninsula and central Europe. In particular, we searched for: (i) floristic and ecological patterns supporting the classification and taxonomic assignment of these grasslands, and (ii) simple relationships between serpentine vegetation characteristics and its physiographic environment. A total of 120 phytosociological releves, of which 52 performed in the Southern Carpathians, were analysed through cluster, ordination and regression procedures. Results Despite some floristic similarities with their Balkan counterparts, the Southern Carpathian ultramafic grasslands were clustered into four distinct groups, which were assigned to as many new syntaxa: Plantago serpentinae-Armerietum halleri, Asplenio serpentini-Achnatheretum calamagrostis, Minuartio frutescentis-Plantaginetum holostei and Sileno saxifragae-Plantaginetum holostei. The latter was best individualised through the occurrence of several Carpathian endemic taxa. The first two ordination axes were significantly related with the terrain slope/presence of xerophilous species and respectively, with site elevation/presence of calcifugous species. The total plant cover showed a unimodal relationship with respect to site elevation. While controlling for the effect of the sampled area, species richness showed a unimodal response to both elevation and slope of the terrain, although their effects were not singular. Conclusions The syntaxonomic distinctiveness of the Southern Carpathian ultramafic grasslands is mainly supported by their overall species composition rather than regional differential species. The main limiting factors driving the composition, cover and species richness of all studied ultramafic grasslands are the water deficit at low elevation and on steep slopes, and the low soil fertility at higher elevations. Our results confirm the previous findings according to which physiographic conditions and, to a lesser extent, soil base nutrients are more important than heavy metal concentrations in structuring the ultramafic vegetation.

Abstract

The article reviews the results obtained through the palynological study of sequences obtained from the Sibiu region and adjacent areas. The oldest Upper Pleistocene sequences we refer to seem to reflect snapshots from the Last Glacial Maximum. The history of the Late Glacial and Holocene vegetation here is broadly part of the succession known for the territory of Romania, in the Carpathians and the surrounding areas of medium and low altitudes. The dynamics of the main forest and grasses taxa were highlighted, influenced both by natural factors and, more recently, by human activity. The reference area is characterized by the domination of the forests during the interstadials and by open landscape of forested steppe during the cold, stadial periods. ©2021 Studia UBB Biologia.

Abstract

Both climate change and human exploitation are major threats to plant life in mountain environments. One species that may be particularly sensitive to both of these stressors is the iconic alpine flower edelweiss (Leontopodium alpinum Colm.). Its populations have declined across Europe due to over-collection for its highly prized flowers. Edelweiss is still subject to harvesting across the Romanian Carpathians, but no study has measured to what extent populations are vulnerable to anthropogenic change. Here, we estimated the effects of climate and human disturbance on the fitness of edelweiss. We combined demographic measurements with predictions of future range distribution under climate change to assess the viability of populations across Romania. We found that per capita and per-area seed number and seed mass were similarly promoted by both favorable environmental conditions, represented by rugged landscapes with relatively cold winters and wet summers, and reduced exposure to harvesting, represented by the distance of plants from hiking trails. Modeling these responses under future climate scenarios suggested a slight increase in per-area fitness. However, we found plant ranges contracted by between 14% and 35% by 2050, with plants pushed into high elevation sites. Synthesis. Both total seed number and seed mass are expected to decline across Romania despite individual edelweiss fitness benefiting from a warmer and wetter climate. More generally, our approach of coupling species distribution models with demographic measurements may better inform conservation strategies of ways to protect alpine life in a changing world.

Abstract

Questions Abiotic filtering, competitive interactions and niche pre-emption effects, as important drivers of the species sorting in plant communities, were hypothesised to be responsible for the amount of concavity and shoulder distinction in ranked species occupancy curves (RSOCs). In connection with the intermediate productivity hypothesis, we proposed an adjustment and extension of the RSOC models concerning the ecological mechanisms underlying their shaping. We aimed at estimating the effects of the variation in resource availability and functional species composition on the RSOCs of 30 woody vegetation syntaxa. Location Low plains to the subalpine belt (southeastern Carpathians) throughout Romania. Methods The fraction of vascular plant species with either low (< 3) or large (>7) Ellenberg ecological indicator values were used as proxies for abiotic variables. Both the standardised effect size of homotoneity (SES-h, estimated by contrasting empirical vs null RSOCs) and the regression parameters of the fitted RSOCs were used, after adjusting them for differences in sampling scale, as shape descriptors. Results The empirical RSOCs were all fitted best by the power exponential function. With increasing fraction of ruderal species and canopy openness, the slopes of RSOC's heads became gentler (larger power parameter). Higher levels of soil fertility towards lower elevations translated in reduced concavity of the RSOCs (larger exponential parameter). Larger/smaller SES-h were associated with richer/poorer habitat-specific species pools that were ascribed to low-elevation, open-canopy vegetation (oak-dominated forests, shiblyak woodlands, secondary scrubs) and, respectively, (sub)montane, closed-canopy, mixed beech or spruce forests and sub-alpine scrubs. Conclusions Dense species packing and even niche partitioning in communities developed in moderately productive sites are associated with shoulder-free, long-tailed, slightly concave RSOCs. Conversely, strong filtering in stressful environments and/or low light availability under closed, woody canopies are related to steep, short-tailed, exponential-like RSOCs. The availability of resources and the equitability of niche partitioning, underlying the process of species sorting during plant community assembly, play a major role in shaping the RSOCs.

Abstract

This phytosociological study of the Carpathian species-rich mesophilous mountain hay meadows (Triseto flavescentis-Polygonion bistortaealliance,Molinio-Arrhenathereteaclass) presents the first unified large-scale classification system in four countries: Slovakia, Poland, Romania and Ukraine. The starting dataset contained releves of theMolinio-Arrhenatheretea,Mulgedio-AconiteteaandNardetea strictaeclasses. Numerical classification and semi-supervised classification by K-means method were used for the analyses. An electronic expert system and diagnostic species for grassland vegetation served for identification ofa priorigroups in K-means method. The final dataset contained 612 releves. Altitude, climatic data and Ellenberg indicator values were used for ecological differentiation of syntaxa. The main gradients in floristic composition were analysed by Detrended Correspondence Analysis. Finally, the eight well-differentiated associations and one newly described association were determined:Campanulo glomeratae-Geranietum sylvatici,Geranio sylvatici-Trisetetum flavescentis,Crepido mollis-Agrostietum capillaris,Geranio-Alchemilletum crinitae,Alchemillo-Deschampsietum caespitosae,Phyteumo (orbicularis)-Trifolietum pratensis,Astrantio-Trisetetum flavescentis,Trollio altissimi-Knautietum dipsacifoliaeandViolo declinatae-Agrostietum capillarisass. nova. The differences in vegetation diversity of mountain hay meadows between particular countries were confirmed:Alchemillo-Deschampsietum caespitosaeoccurs in all studied territories,Campanulo glomeratae-Geranietum sylvaticioccurs predominantly in Slovakia and the newly described associationViolo declinatae-Agrostietum capillarisass. nova could be found only in Ukraine.