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Abstract: The Mura-Drava-Danube transboundary UNESCO Biosphere Reserve represents one of the best-preserved wetlands in Europe. The Reserve’s riparian forests play a significant role in ecosystem functioning and pedunculate oak (Quercus robur) is one of the keystone species of these forests. In recent years, pedunculate oak trees in the Reserve displayed symptoms of necrotic lesions on their leaves. The lesions varied in size, from small, circular to irregular reddish brown to grayish spots to larger necrotic areas that resembled leaf anthracnose and extended along the leaf nerves. In 2021, symptomatic leaves were collected in three countries of the Reserve, i.e. Austria, Slovenia, and Serbia to identify the causative agents of these diseases. Fungal cultures were obtained from symptoms and identified using morphology and multilocus phylogenetic analyses of the ITS rDNA, partial LSU rDNA, tef 1-α, BT2, CAL, ACT, and RPB2 genes. The fungi were identified as Tubakia dryina, Tubakia sp. (Tubakia dryinoides sensu lato), Didymella macrostoma, and Apiognomonia errabunda. Pathogenicity tests done by inoculating the leaves of one-year old pedunculate oak plants revealed that the isolated fungi caused symptoms as those seen in the forest. To our knowledge, this study represents the first report of D. macrostoma as the cause of pedunculate oak leaf spot disease in Serbia and worldwide. It is also the first finding of Tubakia leaf spot disease of pedunculate oak caused by T. dryina in Austria and Serbia. Moreover, Tubakia sp. was proven to be another causative agent of Tubakia leaf spot disease. Additionally, oak anthracnose caused by A. errabunda was found for the first time on pedunculate oak leaves in Austria and Slovenia. During the past decade, pedunculate oak trees have been facing increasing threats from multiple abiotic and biotic factors which has resulted in decline and absence of natural regeneration of these trees. The results of this study add to the understanding of the contributing factors to the decline of pedunculate oak in riparian forests and are important for the development of management strategies to counteract this decline.
Keywords: Mura-Drava-Danube Biosphere Reserve, riparian forests, Tubakia leaf spot, Didymella macrostoma, oak anthracnose, pedunculate oak, leaf spot diseases
Published in DiRROS: 23.04.2024; Views: 1; Downloads: 0
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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: 496; Downloads: 315
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Abstract: Riparian forests are among the most diverse terrestrial ecosystems, yet their biodiversity is increasingly threatened by habitat degradation, climate change, river regulation and invasive species. We investigated deadwood, widely recognized as an indicator for forest biodiversity, in riparian forests of the Mura-Drava-Danube Transboundary Biosphere Reserve. The Biosphere Reserve is a conservation area that spans five countries and three rivers located in south-eastern Europe. In detail, we analyzed the drivers of lying deadwood volume, occurrence and decay related to floodplain type, silvicultural management, and climatic conditions using regression models. Lying deadwood occurrence and volume significantly decreased as distance from the river edge increased, indicating that river dynamics likely play a role in deadwood accumulation in riparian forests. Deadwood volume was also positively influenced by stand basal area, a parameter that can be directly addressed by silvicultural management. Deadwood decay was affected positively by temperature and negatively by precipitation, highlighting the importance of climatic conditions on decay progression. However, in order to draw more accurate conclusions about the drivers and dynamics of deadwood in riparian forests, further monitoring efforts that consider river flooding and flow regime, deadwood transport and saproxylic organism activity in addition to forest management and site conditions, are needed.
Keywords: alluvial forest, hardwood floodplain, deadwood decay, Mura-Drava-Danube transboundary biosphere, reserve, riparian area, softwood floodplain, UNESCO biosphere reserve, wetlands
Published in DiRROS: 18.07.2022; Views: 491; Downloads: 394
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Abstract: The understanding of spatial distribution patterns of native riparian tree species in Europe lacks accurate species distribution models (SDMs), since riparian forest habitats have a limited spatial extent and are strongly related to the associated watercourses, which needs to be represented in the environmental predictors. However, SDMs are urgently needed for adapting forest management to climate change, as well as for conservation and restoration of riparian forest ecosystems. For such an operative use, standard large-scale bioclimatic models alone are too coarse and frequently exclude relevant predictors. In this study, we compare a bioclimatic continent-wide model and a regional model based on climate, soil, and river data for central to south-eastern Europe, targeting seven riparian foundation species%Alnus glutinosa, Fraxinus angustifolia, F. excelsior, Populus nigra, Quercus robur, Ulmus laevis, and U. minor. The results emphasize the high importance of precise occurrence data and environmental predictors. Soil predictors were more important than bioclimatic variables, and river variables were partly of the same importance. In both models, five of the seven species were found to decrease in terms of future occurrence probability within the study area, whereas the results for two species were ambiguous. Nevertheless, both models predicted a dangerous loss of occurrence probability for economically and ecologically important tree species, likely leading to significant effects on forest composition and structure, as well as on provided ecosystem services.
Keywords: bioclimatic model, ecological niche model, forest management, tree species selection, riparian forest habitat, climate change adaptation
Published in DiRROS: 22.03.2021; Views: 1253; Downloads: 846
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