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ReSurveyEurope : a database of resurveyed vegetation plots in Europe
Ilona Knollová, Milan Chytrý, Helge Bruelheide, Stefan Dullinger, Ute Jandt, Markus Bernhardt-Römermann, Idoia Biurrun, Francesco de Bello, Michael Glaser, Stephan M. Hennekens, Mateja Germ, Aleksandra Golob, Janez Kermavnar, Lado Kutnar, Urban Šilc, 2024, pregledni znanstveni članek

Povzetek: Aims We introduce ReSurveyEurope — a new data source of resurveyed vegetation plots in Europe, compiled by a collaborative network of vegetation scientists. We describe the scope of this initiative, provide an overview of currently available data, governance, data contribution rules, and accessibility. In addition, we outline further steps, including potential research questions. Results ReSurveyEurope includes resurveyed vegetation plots from all habitats. Version 1.0 of ReSurveyEurope contains 283,135 observations (i.e., individual surveys of each plot) from 79,190 plots sampled in 449 independent resurvey projects. Of these, 62,139 (78%) are permanent plots, that is, marked in situ, or located with GPS, which allow for high spatial accuracy in resurvey. The remaining 17,051 (22%) plots are from studies in which plots from the initial survey could not be exactly relocated. Four data sets, which together account for 28,470 (36%) plots, provide only presence/absence information on plant species, while the remaining 50,720 (64%) plots contain abundance information (e.g., percentage cover or cover–abundance classes such as variants of the Braun-Blanquet scale). The oldest plots were sampled in 1911 in the Swiss Alps, while most plots were sampled between 1950 and 2020. Conclusions ReSurveyEurope is a new resource to address a wide range of research questions on fine-scale changes in European vegetation. The initiative is devoted to an inclusive and transparent governance and data usage approach, based on slightly adapted rules of the well-established European Vegetation Archive (EVA). ReSurveyEurope data are ready for use, and proposals for analyses of the data set can be submitted at any time to the coordinators. Still, further data contributions are highly welcome.
Ključne besede: biodiversity, monitoring, species richness, vascular plants, vegetation dynamics
Objavljeno v DiRROS: 23.04.2024; Ogledov: 101; Prenosov: 40
.pdf Celotno besedilo (6,59 MB)
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Habitat degradation facilitates the invasion of Neophytes : a resurvey study based on permanent vegetation plots in oak forests in Slovenia (Europe)
Janez Kermavnar, Lado Kutnar, 2024, izvirni znanstveni članek

Povzetek: The spread of neophytes (non-native plant species) challenges the conservation status and ecological integrity of forests, especially in lowland areas. Long-term resurvey studies are needed to evaluate the temporal dynamics of neophytes in forests; however, such data are scarce. In 2023, we resampled a set of 45 permanent vegetation plots (established in 1992/93) in two forest vegetation types: oak–hornbeam forests dominated by Quercus robur and colline oak–beech forests dominated by Q. petraea. Over the last 30 years, oak forests have experienced extensive oak tree mortality, with the degree of habitat degradation being greater in Q. robur forests. In the early 1990s, only three neophytes with low abundance were recorded across all plots. In the 2023 resurvey, the total number of neophytes increased to 22 species (15 herbaceous and 7 woody species), comprising 6.9% of the total species pool in the understory layer. The increase in the plot-level number and cover of neophytes was significant in plots dominated by Q. robur but not in those with Q. petraea. The most frequent neophytes were Impatiens parviflora (present in 31% of plots), Solidago gigantea (27%), Erigeron annuus (16%) and Erechtites hieraciifolia (16%). The richness and cover of neophytes were significantly affected by the tree layer cover (negative correlation) and the degree of soil disturbance (positive correlation). All neophytes established in disturbed patches, whereas the occurrence of I. parviflora was exceptional as it was able to colonize less degraded, shaded understory environments. Habitat degradation (the mortality-induced loss of stand-forming oak trees resulting in extensive tree layer cover decrease) emerged as a key driver promoting neophyte proliferation, coupled with the impact of management-induced disturbances affecting overstory and soil conditions. The spread is expected to continue or even intensify in the future because novel light regimes and disturbances make forest habitats less resistant to neophyte proliferation.
Ključne besede: long-term vegetation change, invasive non-native plants, oak mortality, Quercus robur, Quercus petraea, canopy openness, Impatiens parviflora, Slovenia
Objavljeno v DiRROS: 19.04.2024; Ogledov: 104; Prenosov: 43
.pdf Celotno besedilo (4,46 MB)
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Mixed signals of environmental change and a trend towards ecological homogenization in ground vegetation across different forest types
Janez Kermavnar, Lado Kutnar, 2024, izvirni znanstveni članek

Povzetek: Forest ground vegetation may serve as an early warning system for monitoring anthropogenic global-change impacts on temperate forests. Climate warming may induce a decline of cool-adapted species to the benefit of more thermophilous plants. Nitrogen deposition has been documented to potentially result in soil eutrophication or acidification, which can increase the proportion of species with higher nutrient requirements and species impoverishment caused by competitive exclusion. Abiotic forest disturbances are changing the light conditions in the forest understorey environment. In this resurvey study, we tested the magnitude and direction of change in alpha (species richness) and beta (within-site dissimilarity) diversity and composition of forest ground vegetation in forests of different types in Slovenia over fifteen years. Using plant-derived characteristics (Ellenberg-type indicator values) and by testing a priori predictions concerning expected effects of environmental drivers, we show that the magnitude and direction of forest ground vegetation diversity and floristic changes varies greatly between forest sites. Divergent responses at different sites resulted in low net change of alpha and beta diversity and a weak overall environmental signal. The largest decrease in species number was observed in lowland oak-hornbeam forests, which were also among the sites with the greatest compositional shifts. Changes in beta diversity did not show any consistent trend, and anticipated floristic convergence was not confirmed when all sites were considered. Thermophilization was mainly detected in montane beech sites and alpine spruce forests whereas eutrophication signal was most significant on nutrient-poor sites. Vegetation responses were strongly dependent on initial site conditions. Shrinkage of ecological gradients (process of ecological homogenization) suggests that sites positioned at the ends of the gradients are losing their original ecological character and are becoming more similar to mid-gradient sites that generally exhibit smaller changes. Our results point to the importance of local stand dynamics and overstorey disturbances in explaining the temporal trends in forest ground vegetation. Ground vegetation in Slovenian forests is changing in directions also dictated by multiple regional and global change drivers.
Ključne besede: vegetation resurvey, thermophilization, eutrophication, forest disturbances, alpha and beta diversity, initial site conditions, ICP-Forests network
Objavljeno v DiRROS: 09.04.2024; Ogledov: 143; Prenosov: 55
.pdf Celotno besedilo (1,33 MB)
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Clustering of field maple populations from different ecological conditions in Bosnia and Herzegovina based on discriminant analysis of morphological traits
Stjepan Kvesić, Dalibor Ballian, Mirzeta Memišević Hodžić, 2023, izvirni znanstveni članek

Povzetek: Acer campestre L. is naturally distributed in most of Europe. The species can serve as a valuable model for researching the sensitivity of populations to habitat fragmentation. This research aims to determine whether there is a differentiation of field maple populations based on their division by ecological-vegetation regions, precipitation amounts, temperatures, and altitudes of the populations. The material was collected from 25 populations in Bosnia and Herzegovina, from different ecological-vegetation areas, with twelve trees per population and five fruits and ten leaves per tree. Then, 10 fruit properties and 19 leaf properties were analyzed. A discriminant analysis was performed for population groups based on the ecological-vegetation area, amount of precipitation, average annual air temperature and altitude. The discriminant analysis results showed the distinguishing of groups of populations in the sub-Mediterranean area, and groups of populations with an average annual temperature of 14.00 to 15.99 °C. There was no clear separation of the groups according to the average annual precipitation or altitude. The analysis of the connection established that the influence of environmental factors is more pronounced compared to geographical factors. The key ecological variable that determines morphological separation was temperature and to a lesser extent precipitation. The results of this research will be used in planning of afforestation of suitable, unvegetated land and extreme habitats in the southern and southwestern parts of Bosnia and Herzegovina with Acer campestre.
Ključne besede: Acer campestre, discriminant analysis, ecological-vegetation reionization, population groups differentiation
Objavljeno v DiRROS: 19.03.2024; Ogledov: 135; Prenosov: 70
.pdf Celotno besedilo (1,11 MB)
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Land surface phenology from satellite data : technical report
Urška Kanjir, Ana Potočnik Buhvald, Mitja Skudnik, Liza Stančič, Krištof Oštir, 2022, elaborat, predštudija, študija

Ključne besede: phenology, forest, remote sensing, MODIS, Sentinel-2, vegetation indices
Objavljeno v DiRROS: 29.12.2022; Ogledov: 489; Prenosov: 135
.pdf Celotno besedilo (4,52 MB)

The status and role of genetic diversity of trees for the conservation and management of riparian ecosystems : a European experts' perspective
Filip Alimpić, Jelena Milovanović, Remigiusz Pielech, Georgi Hinkov, Roland Jansson, Simon Dufour, Marcin Beza, Nebi Bilir, Luis Santos del Blanco, Gregor Božič, 2022, izvirni znanstveni članek

Povzetek: Riparian vegetation supports high biodiversity providing many services and is, therefore, an important landscape element. Riparian ecosystems are subject to numerous pressures leading to population decline and genetic erosion of riparian plants. This may have cascading effects at various ecosystem levels, including decreasing ecosystem services, so identifying the current status of genetic diversity of riparian tree species is vital to improve the effectiveness of restoration efforts. We aimed to elicit expert views on the status and importance of genetic diversity of tree species, and conservation needs across European riparian ecosystems. Sharing of such information among researchers, managers and policymakers has the potential to enhance ecological restoration and management of riparian ecosystems. We identified experts in riparian genetic resources conservation and management across Europe. These included stakeholders with different perspectives, ranging from researchers to practitioners. We designed a set of questionnaires where our identified experts were asked to answer questions related to the status and conservation of genetic diversity of riparian tree species in their respective countries. Specifically, we asked about societal awareness, legislative tools, good practices and conservation or restoration projects accounting for intraspecific genetic diversity and differentiation of tree species in riparian ecosystems. Questionnaire responses were analysed and discussed in light of the scientific literature to define needs and priorities related to the management and conservation of genetic diversity of riparian tree species. The experts recognized that a combination of in situ and ex situ measures and/or integrative conservation of riparian ecosystems is the most appropriate option for conserving the genetic diversity of riparian tree species. Simultaneous application of conservation measures at the level of priority species, identified by experts, and protection of riparian areas are required. Synthesis and applications. This study revealed the importance of recognizing the ecological processes that shape the genetic diversity of riparian tree species in hydrographic networks (dendritic spatial configuration, specific patterns of gene flow among riparian populations, fragmentation of river by dams) but also the need to overcome socio-economic barriers, such as lack of policy priority, deficiency in funding and weak legislation framework.
Ključne besede: biodiversity conservation, genetic erosion, genetic resources conservation, knowledge transfer, management, riparian genetic diversity, vegetation
Objavljeno v DiRROS: 08.12.2022; Ogledov: 476; Prenosov: 309
.pdf Celotno besedilo (1,02 MB)
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Variation in floristic and trait composition along environmental gradients in the herb layer of temperate forests in the transition zone between Central and SE Europe
Janez Kermavnar, Lado Kutnar, Aleksander Marinšek, 2022, izvirni znanstveni članek

Povzetek: Species- and trait-environment linkages in forest plant communities continue to be a frequent topic in ecological research. We studied the dependence of floristic and functional trait composition on environmental factors, namely local soil properties, overstory characteristics, climatic parameters and other abiotic and biotic variables. The study area comprised 50 monitoring plots across Slovenia, belonging to the EU ICP Forests monitoring network. Vegetation was surveyed in accordance with harmonized protocols, and environmental variables were either measured or estimated during vegetation sampling. Significant predictors of species composition were identified by canonical correspondence analysis. Correlations between plant traits, i.e. plant growth habit, life form, flowering features and CSR signature, were examined with fourth-corner analysis and linear regressions. Our results show that variation in floristic composition was mainly explained by climatic parameters (mean annual temperature, mean annual precipitation), soil properties (pH) and tree layer-dependent light conditions. Trait composition was most closely related with tree layer characteristics, such as shade-casting ability (SCA, a proxy for light availability in the understory layer), tree species richness and tree species composition. Amongst soil properties, total nitrogen content and soil texture (proportion of clay) were most frequently correlated with different species traits or trait states. The CSR signature of herb communities was associated with tree layer SCA, soil pH and mean annual temperature. The floristic composition of the studied herb-layer vegetation depended on temperature and precipitation, which are likely to be influenced by ongoing climate change (warming and drying). Trait composition exhibited significant links to tree layer characteristics and soil conditions, which are in turn directly modified by forest management interventions.
Ključne besede: vegetation–environment relationship, floristic composition, life-history traits, herbaceous species, Slovenia
Objavljeno v DiRROS: 15.04.2022; Ogledov: 676; Prenosov: 406
.pdf Celotno besedilo (2,43 MB)
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Carbon flux and environmental parameters data from an eddy covariance tower in a mid-succession ecosystem developed on abandoned karst grassland in Slovenia (2012-2019)
Koffi Dodji Noumonvi, Klemen Eler, Dominik Vodnik, Primož Simončič, Mitja Ferlan, 2021, zaključena znanstvena zbirka raziskovalnih podatkov

Povzetek: This data set was used to estimate carbon fluxes by comparing eddy covariance tower (Long = 13.916701, Lat = 45.543491) measurements with vegetation indices based estimates.
Ključne besede: eddy covariance, GPP, NEE, empirical model, LUE model, vegetation photosynthesis model, vegetation indices
Objavljeno v DiRROS: 21.02.2022; Ogledov: 825; Prenosov: 642
Celotno besedilo (29,63 KB)
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Empirical vs. light-use efficiency modelling for estimating carbon fluxes in a mid-succession ecosystem developed on abandoned karst grassland
Koffi Dodji Noumonvi, Mitja Ferlan, 2020, izvirni znanstveni članek

Povzetek: Karst systems represent an important carbon sink worldwide. However, several phenomena such as the CO2 degassing and the exchange of cave air return a considerable amount of CO2 to the atmosphere. It is therefore of paramount importance to understand the contribution of the ecosystem to the carbon budget of karst areas. In this study conducted in a mid-succession ecosystem developed on abandoned karst grassland, two types of model were assessed, estimating the gross primary production (GPP) or the net ecosystem exchange (NEE) based on seven years of eddy covariance data (2013%2019): (1) a quadratic vegetation index-based empirical model with five alternative vegetation indices as proxies of GPP and NEE, and (2) the vegetation photosynthesis model (VPM) which is a light use efficiency model to estimate only GPP. The Enhanced Vegetation Index (EVI) was the best proxy for NEE whereas SAVI performed very similarly to EVI in the case of GPP in the empirical model setting. The empirical model performed better than the VPM model which tended to underestimate GPP. Therefore, for this ecosystem, we suggest the use of the empirical model provided that the quadratic relationship observed persists. However, the VPM model would be a good alternative under a changing climate, as it is rooted in the understanding of the photosynthesis process, if the scalars it involves could be improved to better estimate GPP.
Ključne besede: eddy covariance, carbon flux, GPP, NEE, vegetation indices, remote sensing, satellite data, GPP map
Objavljeno v DiRROS: 03.01.2022; Ogledov: 718; Prenosov: 472
.pdf Celotno besedilo (3,07 MB)
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Empirical approach for modelling tree phenology in mixed forests using remote sensing
Koffi Dodji Noumonvi, Gal Oblišar, Ana Žust, Urša Vilhar, 2021, izvirni znanstveni članek

Povzetek: : Phenological events are good indicators of the effects of climate change, since phenological phases are sensitive to changes in environmental conditions. Although several national phenological networks monitor the phenology of different plant species, direct observations can only be conducted on individual trees, which cannot be easily extended over large and continuous areas. Remote sensing has often been applied to model phenology for large areas, focusing mostly on pure forests in which it is relatively easier to match vegetation indices with ground observations. In mixed forests, phenology modelling from remote sensing is often limited to land surface phenology, which consists of an overall phenology of all tree species present in a pixel. The potential of remote sensing for modelling the phenology of individual tree species in mixed forests remains underexplored. In this study, we applied the seasonal midpoint (SM) method with MODIS GPP to model the start of season (SOS) and the end of season (EOS) of six different tree species in Slovenian mixed forests. First, substitute locations were identified for each combination of observation station and plant species based on similar environmental conditions (aspect, slope, and altitude) and tree species of interest, and used to retrieve the remote sensing information used in the SM method after fitting the best of a Gaussian and two double logistic functions to each year of GPP time series. Then, the best thresholds were identified for SOS and EOS, and the results were validated using cross-validation. The results show clearly that the usual threshold of 0.5 is not best in most cases, especially for estimating the EOS. Despite the difficulty in modelling the phenology of different tree species in a mixed forest using remote sensing, it was possible to estimate SOS and EOS with moderate errors as low as <8 days (Fagus sylvatica and Tilia sp.) and <10 days (Fagus sylvatica and Populus tremula), respectively.
Ključne besede: phenology modelling, start of season, end of season, remote sensing, MODIS GPP, vegetation indices, threshold methods
Objavljeno v DiRROS: 23.08.2021; Ogledov: 950; Prenosov: 695
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