1. Tubakia spp., Didymella macrostoma and Apiognomonia errabunda causing leaf spot and anthracnose of Quercus robur in the Mura-Drava-Danube Biosphere ReserveMilica Zlatković, Marcus Sallmannshofer, Silvio Schueler, Thomas L. Cech, Milutin Djilas, Gernot Hoch, Katharina Lapin, Nikica Ogris, Barbara Piškur, Katharina Schwanda, Srđan Stojnić, Marjana Westergren, Saša Orlović, 2024, original scientific article 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: 46; Downloads: 12
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2. Infestation intensity by the invasive oak lace bug, Corythucha arcuata (Say) in mixed and pure oak standsGernot Hoch, Alex Stemmelen, Eötvös Csaba Béla, Werner Hinterstoisser, Miran Lanšćak, Srđan Stojnić, Máté Tóth, Marjana Westergren, Simon Zidar, Milica Zlatković, Nikola Zoric, Maarten De Groot, 2024, original scientific article Abstract: There has been accumulating evidence for effects of tree species composition on herbivory with many examples of lower damage by specialist feeders in tree species rich forests. In a joint study in five Central and Southeastern European countries, we studied the effect of tree species richness on infestation intensity of the oak lace bug, Corythucha arcuata (Say) (Heteroptera, Tingidae), an invasive pest on oak trees that has spread rapidly across the Balkan Peninsula and Central Europe. Intensity of infestation by C. arcuata on oaks was assessed on three or four study plots with high (pure stands) and three or four plots with low percentage of oak (mixed stands) in each country. Ordinal regression analysis showed that intensity of infestation of trees by C. arcuata differed between countries; no significant effect of stand type (mixed or pure) on infestation levels was detected. When analysing the percentage of trees in the highest infestation class, stand type had a significant effect with more intensive infestation in pure stands. We conclude that mixed stands will not prevent severe infestation but may help mitigating the impact of established C. arcuata populations.
Keywords: associational resistance, Corythucha arcuata, diversity, host tree concentration, invasive forest pest
Published in DiRROS: 14.11.2023; Views: 289; Downloads: 176
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3. Forest managers’ perspectives on environmental changes in the biosphere reserve Mura-Drava-DanubeMarcus Sallmannshofer, Rok Damjanić, Harald Vacik, Marjana Westergren, Tjaša Baloh, Gregor Božič, Mladen Ivanković, Gyula Kovács, Miran Lanšćak, Katharina Lapin, Laszlo Nagy, Silvija Krajter Ostoić, Saša Orlović, Srđan Stojnić, Peter Železnik, Milica Zlatković, Silvio Schueler, 2023, original scientific article Abstract: Riparian forests are particularly vulnerable to environmental change and anthropogenic influences because they are highly dynamic ecosystems, thus proper adaptation measures are crucial. The implementation of these measures, however, strongly depends on the actors’ perceptions of the specific problems occurring in such forests. For understanding the constraints of specific interest groups toward different adaptation activities, information in this field is essential. By conducting a questionnaire survey we explore how different types of forest managers, i.e., forestry professionals, forest owners, and conservation managers, perceive the effects of environmental change on forest management in the recently established Transboundary Biosphere Reserve Mura-Drava-Danube. We show that these forest managers are highly aware of ongoing environmental changes and appraise deteriorating forest conditions, especially after observing changes themselves. Abiotic damage is expected to increase the most, followed by biotic damage, the spread of non-native species, and tree dieback. Nearly 80% of the survey respondents expect further changes and almost all of them intend to adapt their management of forests to mitigate or prepare for these changes. Nevertheless, we show differences in sensitivity to change and willingness to initiate adaptation actions by assessing adaptation thresholds: conservation managers appear generally more tolerant to changes, which results in higher thresholds to initiate management adaptation than forestry professionals
Keywords: biosphere reserve Mura-Drava-Danube, forest management, sensitivity to environmental change, stakeholder perception, adaptation thresholds, riparian forest tree species
Published in DiRROS: 31.05.2023; Views: 345; Downloads: 270
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4. Comparing environmental impacts of alien plants, insects and pathogens in protected riparian forestsKatharina Lapin, Sven Bacher, Thomas L. Cech, Rok Damjanić, Franz Essl, Freya-Isabel Georges, Gernot Hoch, Andreja Kavčič, András Koltay, Saša Kostić, Ivan Lukić, Aleksander Marinšek, Laszlo Nagy, Sonja Novak Agbaba, Janine Oettel, Saša Orlović, Leopold Poljaković-Pajnik, Marcus Sallmannshofer, Martin Steinkellner, Srdjan Stojnić, Marjana Westergren, Milica Zlatković, Anita Zolles, Maarten De Groot, 2021, original scientific article Abstract: The prioritization of alien species according to the magnitude of their environmental impacts has become increasingly important for the management of invasive alien species. In this study, we applied the Environmental Impact Classification of Alien Taxa (EICAT) to classify alien taxa from three different taxonomic groups to facilitate the prioritisation of management actions for the threatened riparian forests of the Mura-Drava-Danube Biosphere Reserve, South East Europe. With local experts we collated a list of 198 alien species (115 plants, 45 insects, and 38 fungi) with populations reported in southeast European forest ecosystems and included them in the EICAT. We found impact reports for 114 species. Eleven of these species caused local extinctions of a native species, 35 led to a population decrease, 51 to a reduction in performance in at least one native species and for 17 alien species no effects on individual fitness of native species were detected. Fungi had significantly highest impact and were more likely to have information on their impacts reported. Competition and parasitism were the most important impact mechanisms of alien species. This study is, to our knowledge, the first application of EICAT to all known alien species of several taxonomic groups in a protected area. The impact rankings enabled to identify taxa that generally cause high impacts and to prioritize species for the management in protected areas according to their impact magnitudes. By following a standardized impact protocol, we identified several alien species causing high impacts that do not appear on any expert-based risk list, which are relevant for policymakers. Thus, we recommend that alien species be systematically screened to identify knowledge gaps and prioritize their management with respect to spatio-temporal trends in impact magnitudes.
Keywords: alien species, biological invasions, EICAT, invasive species management, protected areas, species prioritization
Published in DiRROS: 29.10.2021; Views: 827; Downloads: 658
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