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Query: "author" (Vilhar Urša) .

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1.
The effects of large-scale forest disturbances on hydrology : an overview with special emphasis on karst aquifer systems
Urša Vilhar, Janez Kermavnar, Erika Kozamernik, Metka Petrič, Nataša Ravbar, 2022, original scientific article

Abstract: Large-scale forest disturbances (LSFD) are an essential component of forest ecosystem dynamics. The effects of rapid loss of forest cover and other changes in forest ecosystems are inextricably linked to hydrologic processes such as evapotranspiration, soil and recharge processes. Among all hydrogeological systems, karst aquifers are important because of their exceptionally rich and unique biodiversity, biomass, and groundwater resources. At the same time, they are characterized by specific hydrological processes that make them highly vulnerable to environmental changes. Therefore, this study paid special attention to the effects of LSFD on karst hydrology. Using the PRISMA checklist, a thorough literature review of studies published between 2001 and 2020 was compiled into a comprehensive matrix dataset. In addition, an initial assessment of the global and regional distribution of forests on carbonate rocks was made based on publicly available geodatabases of forests and karst aquifers. The compiled information provides the first global overview of hydrological processes affected by LSFD, and identifies important knowledge gaps and future research challenges. The matrix dataset contained 117 full-text articles with a total of 160 case studies. Most publications were from 2011 to 2017, with more than half of the studies at the plot level and more than one-third at the catchment level. Studies on the effects of fires and pest and diseases infestations predominated. However, no articles were found on the effects of ice storms on hydrology in general or on the effects of pest and disease infestations on hydrology in karst areas. Of the 45.6 M km2 of forested land worldwide, 6.3 M km2 or 13.9% of all forests are underlain by carbonate rocks. Carbonate rocks cover about 15% of the land surface, which means that 31.3% of the world's karst aquifers are covered by forest. 29% of all case studies were conducted in karst areas, which is a high proportion compared to the proportion of forests in karst areas. However, these studies are unevenly distributed geographically. Most studies were conducted at the plot level, and only 21% of studies focused on natural LSFD, so forest management and land use change studies predominated. Although studies on the effects of LSFD on evapotranspiration processes between vegetation, air and soil are fairly well represented, infiltration and recharge processes in karst areas remain poorly understood and knowledge is lacking, particularly on groundwater flow and related hydrological processes. Regional studies and impacts on groundwater resources are also insufficient. The results indicate an urgent need for an integrated holistic interdisciplinary approach and a comprehensive understanding of the individual influencing factors, which would allow more accurate modelling of hydrological processes in forested karst aquifers.
Keywords: natural disasters, climatic changes, evapotranspiration, hydrology, karst aquifers
Published in DiRROS: 19.05.2023; Views: 24; Downloads: 13
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Forest subsidy distribution in five European countries
Elena Haeler, Andreas Bolte, Rafael Buchacher, Harri Hänninen, R. Jandl, Artti Juutinen, Katharina Kuhlmey, Mikko Kurttila, Gun Lidestav, Raisa Mäkipää, Lydia Rosenkranz, Matevž Triplat, Urša Vilhar, Kerstin Westin, Silvio Schueler, 2023, original scientific article

Abstract: Forest subsidies are widely used to achieve policy objectives aimed at maintaining and supporting the provision of the various ecosystem services provided by forests. In the European Union, an important instrument is the European Agricultural Fund for Rural Development (EAFRD) within the EU's Common Agricultural Policy (CAP), but countries also have national subsidy systems. In both cases, individual countries determine which objectives they want to achieve with the subsidy schemes and which measures are supported. In this comparative study, we investigate which forest-related measures are subsidized across Europe and which forest owners, representing a very heterogeneous group, are involved in the activities of the subsidy systems. We collected data on subsidies paid out for forest-related measures from Austria, Finland, Germany, Slovenia and Sweden from the EAFRD funding period 2014–2020 for a comparison of the funded activities. Further, we analysed how subsidies were distributed among private forest owners with forest holdings of different sizes by performing G-tests to compare the observed with the expected subsidies received by forest owners in the different size categories. The results show that through the flexibility given by the CAP for countries to adjust their subsidy programmes to the specific national needs, EAFRD funds and equivalent national subsidies are indeed used for a wide range of activities instead of only a few following one common European goal. Reflecting the different needs and various forest functions, the subsidized activities range from the more ecology-oriented “investment to increase resistance and the ecological value of forests” to the more management-oriented “purchase of new machinery and new equipment for forestry operations”. In all five countries, small-scale forest owners with holdings smaller than 200 ha are the largest owner group and manage a large share of the forest area in private hands (from 47% in Austria to 97% in Slovenia). However, especially owners of the smallest holdings (< 20 ha) rarely use the funding scheme of the EAFRD framework and thus receive a disproportionately low share of subsidies. There might be several reasons for this. Small-scale forest owners are generally less involved regarding policy issues (including subsidy schemes) than owners of larger forest holdings and may not be aware of all funding opportunities. In addition, the considerable effort to apply, including project preparation, administration and documentation may be perceived as a barrier. It became clear that the current subsidy systems of the countries focus on different forest policy objectives. Our study further revealed that the documentation of subsidy distribution is partly unclear and inconsistent across countries hampering European comparisons. However, understanding current subsidy distribution is urgently needed for increasing the effectiveness of subsidy systems to achieve European policy goals of vital multifunctional forests.
Keywords: European agricultural fund for rural development, EAFRD, policy, incentives, multifunctional forests, small-scale forest owners, bioeconomy
Published in DiRROS: 05.01.2023; Views: 231; Downloads: 113
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4.
Hoverflies (Diptera: Syrphidae) as biodiversity indicators for assessing urban forest habitats
Maarten De Groot, Primož Simončič, Andrej Verlič, Urša Vilhar, 2022, original scientific article

Abstract: Urban and peri-urban forests are important habitats for maintaining biodiversity in cities. In this paper, we report a method for using hoverflies as biodiversity indicators in urban forest habitats. As a case study, forest habitats in three peri-urban and urban forests were assessed and compared to rural forests in Slovenia. Rožnik (Ljubljana) was chosen as the urban forest site, Mestni log (Ljubljana) and Brdo (Kranj) were chosen as the peri-urban sites, and eight sites were chosen in rural forests in different ecoregions in Slovenia. Forest hoverfly species richness and the species composition of different biological traits were compared between the peri-urban forests, urban forest and rural forest sites. In addition, species richness was assessed for changes in response to weather conditions between years. The number of species with the investigated traits in the urban and peri-urban forests was within the range of the number of species observed in the rural forests. The number of saproxylic species was higher in the urban forest but lower in the peri-urban forests compared to the rural forests. The proportions of species with different feeding modes and different development times were similar between the peri-urban, urban and rural forests. The proportions of species with development times of less than 2 months or more than 1 year and of predatory species were similar in the urban and peri-urban forests but higher in the rural forests. The species composition of the other biological traits differed between the peri-urban, urban and rural forests. Species richness and abundance displayed large differences in phenological patterns between 2012 and 2013; these differences are related to differences in the minimum temperature for these years. The results are discussed in relation to forest management in urban forests, the usefulness of hoverflies as a biodiversity indicator and possible extrapolation to other species groups.
Keywords: biological traits, ecosystem services, forest management, saproxylic species, Syrphidae, urban forest
Published in DiRROS: 30.12.2022; Views: 778; Downloads: 450
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5.
Common preferences of European small-scale forest owners towards contract-based management
Artti Juutinen, Elena Haeler, R. Jandl, Katharina Kuhlmey, Mikko Kurttila, Raisa Mäkipää, Tähti Pohjanmies, Lydia Rosenkranz, Mitja Skudnik, Matevž Triplat, Anne Tolvanen, Urša Vilhar, Kerstin Westin, Silvio Schueler, 2022, original scientific article

Abstract: The societal demands on forest management are becoming increasingly diverse, which will be reflected in decisions made by forest owners. We examined the willingness of private forest owners in Austria, Finland, Germany, Slovenia, and Sweden to participate in a contract-based payment scheme in which they were asked to apply a specific management strategy to promote either timber production or environmental goals. The preferences for the contract-based management and associated consequences in terms of profitability, biodiversity, carbon stock, and climate change-induced damages were addressed within a choice experiment. A majority of respondents across all countries agreed to participate in a payment scheme to promote environmental goals, while schemes purely targeted to increase wood production were found less attractive. Forest owners liked improvements in profitability and environmental attributes and disliked deterioration of these attributes. Differences among countries were found in the level of expected contract payments, and commonalities were found with respect to preferences towards environmental goals, including biodiversity and carbon stocks. Hence, new policies to target European forest subsidy to promote the provision of environmental goals would likely be acceptable.
Keywords: choice experiment, ecosystem services, forest policy, incentives, private forest owners
Published in DiRROS: 29.09.2022; Views: 211; Downloads: 117
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Rainfall interception in urban forests is related to stand structure
Janez Kermavnar, Urša Vilhar, 2016, published scientific conference contribution abstract

Published in DiRROS: 03.11.2021; Views: 517; Downloads: 192
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9.
Fine root dynemics in Slovenian beech forests in relation to soil temperature and water availability
Peter Železnik, Urša Vilhar, Mike Starr, Maarten De Groot, Hojka Kraigher, 2015, published scientific conference contribution abstract

Published in DiRROS: 03.11.2021; Views: 452; Downloads: 168
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10.
Empirical approach for modelling tree phenology in mixed forests using remote sensing
Koffi Dodji Noumonvi, Gal Oblišar, Ana Žust, Urša Vilhar, 2021, original scientific article

Abstract: : 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.
Keywords: phenology modelling, start of season, end of season, remote sensing, MODIS GPP, vegetation indices, threshold methods
Published in DiRROS: 23.08.2021; Views: 664; Downloads: 511
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