Abstract

Soil organic carbon (SOC) is crucial for ecosystem function and carbon storage, especially in mountain regions where cooler temperatures limit microbial activity, leading to higher SOC stocks compared to lowlands. However, the available data are insufficient to fully understand the distribution of SOC properties along elevation and snow cover duration gradients. Given that climate change models predict a reduction in snow cover duration, it is essential to better characterize these properties at a finer, mesotopographic scale (e.g., ridges and slopes), corresponding to the distribution of mountain plant communities. This study investigates the impact of microclimate on SOC content and stability in European mountain grasslands. We focused on two types of grasslands on acidic soils to maintain homogeneity in key parameters such as soil properties and plant communities. These grasslands, located across temperate European mountain ranges (Alps, Pyrenees, Vosges, Balkans, Carpathians, Black Forest, Bohemian Forest, and Sudetes), span a gradient of snow cover duration, ranging from frost-exposed ridges dominated by Carex curvula, to intermediate grasslands, without frost, dominated by Nardus stricta. SOC content and stability were assessed using Rock-Eval (R) thermal analysis across all sites. The results indicate that microclimate significantly influences SOC properties. Cooler temperatures, driven by elevation and reduced snow cover duration, were associated with increased SOC content but decreased stability. On windy ridges, extended growing seasons combined with intense winter freezing led to higher SOC lability, as freezing slows down mineralization processes. In contrast, intermediate grasslands, with longer growing seasons, showed enhanced SOC stability due to higher decomposition activity. These findings provide valuable insights into how SOC properties may evolve under climate change, particularly in relation to rising temperatures and shifting snow cover dynamics.

Abstract

Background and Aims Studying trait variability and restricted gene flow between populations of species can reveal species dynamics. Peripheral populations commonly exhibit lower genetic diversity and trait variability due to isolation and ecological marginality, unlike central populations experiencing gene flow and optimal conditions. This study focused on Carex curvula, the dominant species in alpine acidic meadows of European mountain regions. The species is sparser in dry areas such as the Pyrenees and Balkans, compared to the Central-Eastern Alps and Carpathians. We hypothesized that distinct population groups could be identified based on their mean functional trait values and their correlation with the environment; we predicted that ecologically marginal populations would have stronger trait correlations, lower within-population trait variability (intraspecific trait variability, ITV) and lower genetic diversity than populations of optimal habitats. Methods Sampling was conducted in 34 populations that spanned the entire distribution range of C. curvula. We used hierarchical clustering to identify emergent functional groups of populations, defined by combinations of multiple traits associated with nutrient economy and drought tolerance (e.g. specific leaf area, anatomy). We contrasted the geographical distribution of these groups in relation to environment and genetic structure. We compared pairwise trait relationships, within-population trait variation (ITV) and neutral genetic diversity between groups. Key Results Our study identified emergent functional groups of populations. Those in the southernmost ranges, specifically the Pyrenees and Balkan region, showed drought-tolerant trait syndromes and correlated with indicators of limited water availability. While we noted a decline in population genetic diversity, we did not observe any significant changes in ITV in ecologically marginal (peripheral) populations. Conclusions Our research exemplifies the relationship between ecological marginality and geographical peripherality, which in this case study is linked to genetic depauperation but not to reduced ITV. Understanding these relationships is crucial for understanding the biogeographical factors shaping trait variation.

Abstract

Odd ploidy-level cytotypes in sexually reproducing species are considered a dead end due to absent or reduced fertility. If sterility is only partial, however, their contribution to the population gene pool can be augmented by longevity and clonal growth. To test this, we investigated the cytotype origin and spatial pattern, and pollen viability in three relict shrub species of the genus Daphne (Thymelaeaceae Juss.) in central Europe. Daphne cneorum subsp. cneorum is a widespread European species that has a broad ecological amplitude, whereas D. cneorum subsp. arbusculoides and D. arbuscula are narrow endemics of the western Pannonian Plain and the Western Carpathians, respectively. Our study confirmed that all three taxa are diploid. However, of more than a thousand analysed individuals of D. cneorum subsp. cneorum, five in four different populations were triploid. Our data indicate that these triploids most likely originate from recurrent autopolyploidization events caused by the fusion of reduced and unreduced gametes. High pollen viability was observed in all three taxa and in both diploid and triploid cytotypes, ranging from 65 to 100 %. Our study highlights the significant role of odd ploidy-level cytotypes in interploidy gene flow, calling for more research into their reproduction, genetic variability, and overall fitness. Interestingly, while the endemic D. arbuscula differs from D. cneorum based on genetic and genome size data, D. cneorum subsp. arbusculoides was indistinguishable from D. cneorum subsp. cneorum. However, our study reveals that the subspecies differ in the number of flowers per inflorescence. This is the first comprehensive cytogeographic study of this intriguing genus at a regional scale, and in spite of its karyological stability, it contributes to our understanding of genomic evolution in plant species with a wide ecological amplitude. The presented study sheds light on the emergence of odd-ploidy cytotypes in diploid species, specifically in long-lived relic shrubs from the genus Daphne (Thymeleaceae). Rare odd-ploidy cytotypes are generally considered maladaptive in sexual diploid species due to reduced fitness and fertility. However, our research revealed the independent and recurring evolution of triploid cytotypes, most likely arising via the fusion of reduced and unreduced gametes in exclusively diploid systems and exhibiting significant pollen fertility. Their even partial pollen fertility, especially, in the context of their longevity, can contribute to a more diverse gene pool in their parental diploid populations or even to the spontaneous emergence of new cytotypes. Additionally, we demonstrated that although Daphne cneorum exhibits a large ecological amplitude, spanning various bedrock substrates and altitudinal ranges, its diploid genomes remain highly stable with no ecologically driven genome size expansions or reductions, as previously observed in many species with large ecological amplitudes.

Abstract

Abstract

Romania hosts a relatively high species diversity, including 3,829 vascular and 979 non-vascular spontaneous plant taxa. Multiple national red lists exist, with the number of taxa assessed as threatened varying greatly between them, from 548 to 1,438, and with number of taxa assigned to a given threat category also varying between the different sources. A composite list including all taxa mentioned in at least one of the selected red listings from Romania is required in order to compensate for this lack of consensus and to assess their ex situ conservation status. In this study, we synthesized data from the national red lists and counted 1,220 spontaneous vascular plant species and 201 subspecies, of which 77 are endemic and 76 subendemic for Romania. In addition, 18 non-red-listed endemics and 14 subendemics have been added, bringing the total to 1,453 threatened and (sub)endemic plant taxa, representing almost 38% of the total native vascular flora of Romania. Despite the large network of protected areas in Romania, many taxa are still being threatened with extinction in the region mainly due to anthropogenic pressure. Several ex situ conservation measures have been employed to assure a more substantial buffer against plant extinction in the wild, supported by thorough and adequate conservation strategies and multiple means to reintroduce taxa back to their natural habitats. Consequently, our second aim was to evaluate the ex situ conservation status of these threatened and (sub)endemic plants from Romania, focussing on both conventional methods (cultivation in botanic gardens, seed banking) and biotechnological approaches (in vitro tissue culture, medium-term storage and cryostorage). Of the 1,453 taxa included in our list, 642 (44.2%) are conserved by ex situ approaches. Of these, 524 are harboured in the most important botanic gardens throughout Romania, while 156 are currently held in long-term seed banks locally or in the Millennium Seed Bank of the Royal Botanic Garden, Kew (UK). Conversely, only 64 taxa from the list are preserved at the national level through in vitro cultures, and cryopreservation protocols have been developed for only 8 taxa. Overall, more than half of the threatened and (sub)endemic vascular flora from Romania remains unprotected outside the classical in situ conservation measures. For red-listed bryophytes, only 0.6% are preserved in national ex situ collections. Moreover, some aspects related to population genetic studies and the genetic stability of ex situ conserved plants are also briefly discussed, as essential prerequisites for applied biodiversity conservation programs. Finally, considering the distribution range of targeted taxa, we included a synthesis of biotechnological approaches at both national and international level. Our study presents not only a first assessment of the ex situ conservation status of national red listed flora, but also, to our knowledge, the most comprehensive and updated overview of the rare, threatened and (sub)endemic taxa from Romania. This evaluation will provide a supporting tool for national decision-and policy-making actions for biodiversity conservation, using both in situ and ex situ approaches. We also highlight the need for an updated red list for the Romanian flora that accurately follows the IUCN assessment criteria and protocols.

Abstract

The European Alps are highly rich in species, but their future may be threatened by ongoing changes in human land use and climate. Here, we reconstructed vegetation, temperature, human impact and livestock over the past ~12,000 years from Lake Sulsseewli, based on sedimentary ancient plant and mammal DNA, pollen, spores, chironomids, and microcharcoal. We assembled a highly-complete local DNA reference library (PhyloAlps, 3923 plant taxa), and used this to obtain an exceptionally rich sedaDNA record of 366 plant taxa. Vegetation mainly responded to climate during the early Holocene, while human activity had an additional influence on vegetation from 6 ka onwards. Land-use shifted from episodic grazing during the Neolithic and Bronze Age to agropastoralism in the Middle Ages. Associated human deforestation allowed the coexistence of plant species typically found at different elevational belts, leading to levels of plant richness that characterise the current high diversity of this region. Our findings indicate a positive association between low intensity agropastoral activities and precipitation with the maintenance of the unique subalpine and alpine plant diversity of the European Alps. © 2022, The Author(s).

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

Abstract

Intraspecific trait variability (ITV) is an important component of functional ecology studies. While functional biogeography requires us to understand broad-scale patterns of trait distribution, ITV remains inadequately studied. Due to isolation of ranges, habitat fragmentation and sharp topoclimatic gradients over short distances, temperate mountains offer opportunities to study the ITV in widespread species. In this study, we explored ITV in geographically separated populations of matgrass (Nardus stricta), a clonal dominant plant species of mountain pastures. We measured plant height and leaf traits in 55 populations distributed across six European mountain ranges (from the Pyrenees to the Carpathians) to examine the structure of ITV. We hypothesised that the leaf economics spectrum (LES) and plant size exhibit a strong convergence across a prevailing gradient of growing season length (GSL). We then partitioned the ITV into between ranges, between populations nested in ranges and between individuals nested in populations, and examined the role of climate and local variables on the spatial variation and covariation of traits. Traits showed large ITV and higher between- than within-population variability. Leaf traits displayed a high dependency on height reflecting the growing phase climate and other local factors, while range identity alone (differentiation between ranges) explained a low to moderate amount of the variability in the traits. The strength of coordination between several of the LES traits was higher under shorter GSL due to late snowmelt, suggesting higher phenotypic integration. In the context of functional biogeography of mountain ecosystems, allometric effects and growing phase climate are both key to understanding ITV. We discuss the implications of these findings as they relate to future comparative studies of ITV in seasonal environments.

Abstract

Effective conservation of biodiversity should build on a strong basis of taxonomic and spatial distribution knowledge. The Carpathian Mountains, an iconic centre of biodiversity in temperate Europe, harbour a remarkable number of endemic vascular plants. Current knowledge on their taxonomic status, spatial distribution and genetic diversity is, however, incomplete. Research and conservation efforts have mostly been country specific, resulting in contrasting chorological knowledge and taxonomic acceptance between neighbouring countries, and differing conservation policies. Urgent synchronisation of cross-border conservation measures is required. Here, we present an overview of a new international project that will address these issues, outlining the current state of knowledge and theoretical background concerning Carpathian subendemics and endemics in order to improve their conservation status. The project involves partners from eight countries, working collaboratively in conservation, research and sharing of standardised data for the Carpathian flora. Long-term seed conservation of 500 species, with a focus on endemics, regionally endangered species and range-margin populations from the Carpathians, will be used as an effective measure for the conservation of Carpathian endemics and endangered species. Research focused on the biosystematics of selected taxa will increase our knowledge of the evolutionary processes involved in the origin of the Carpathian flora. Finally, the establishment of the Carpathian Research Network (CRN) provides an official framework for pooling, sharing and standardising scientific data on Carpathian endemics from different countries. The CRN is developing an online database of the distribution of selected species (The Carpathian Endemics Distribution Database, CEDD) including their intrinsic and extrinsic traits and current opinion on their taxonomic status. This will be used to produce a monograph on the Carpathians' endemic flora.