1. Turkey oak (Quercus cerris L.) is more drought tolerant and better reflects climate variations compared to pedunculate oak (Quercus robur L.) in lowland mixed forests in northwestern Serbia : ǂa ǂstable carbon isotope ratio (δ13C) and radial growth approachSaša Kostić, Tom Levanič, Saša Orlović, Bratislav Matović, Dejan Stojanović, 2022, original scientific article Abstract: Tree-ring width (TRW), stable carbon isotope ratio (δ13C) and intrinsic water use efficiency (iWUE) data set chronologies were built for the period 1961–2000 for two oak species (pedunculate oak – Quercus robur L. and Turkey oak – Quercus cerris L.) in northwestern Serbia (Vojvodina province). We focused on the response of the two oak species to measured meteorological data (temperature, precipitation and cloud cover), drought events expressed by six meteorological drought indices, and river water level to better understand their drought tolerance and stress and to assess the reliability of the species response to climate and drought indices when using TRW or δ13C. Turkey oak exhibited better drought tolerance (and less drought stress) compared to pedunculate oak, as manifested, respectively, by less negative δ13C and lower iWUE values. Based on a generalised additive mixed model (GAMM) among the six drought indices studied, the standardised precipitation evapotranspiration index and the standardised precipitation index showed the best fit with both TRW and δ13C, while the Palmer drought severity index exerted a strong influence only on TRW. It was thus concluded that δ13C responds more strongly and rapidly to climate variations than TRW. Keywords: dendrochronology, stable carbon isotope, tree ring, Quercus robur, Quercus cerris, drought, climate change Published in DiRROS: 04.08.2022; Views: 662; Downloads: 488
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2. 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: 870; Downloads: 677
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