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The impact of climate change on insect pests is an emerging topic in forestry and forest science. This study investigates the relationships between two broadleaved forest pests – spongy moth (Lymantria dispar L.) and brown-tail moth (Euproctis chrysorrhoea L.) – and oaks (Quercus sp.) as their hosts. Oak forests cover almost one-third of the total forest area of Serbia and are ecologically very valuable, but at the same time vulnerable, as being affected in adverse ways by several primary pests and pathogens. Since 1862, Serbia experienced several extremely large outbreaks of spongy moth with more than a hundred thousand hectares completely defoliated each time, while brown-tail moth occurred periodically with a much lower spatial extent. The aim of this research was to investigate the effect of UV radiation (UVR) and air temperature on spongy moth and brown-tail moth in Serbian forests. We used simulations of the coupled regional climate model EBU-POM (Eta Belgrade University-Princeton Ocean Model) for the A1B scenario for the period 2001-2030 as main input and different statistical methods to explore relationships between observations of pest spread and climate change impacts. Our results suggest (i) increasing the areas affected by spongy moth due to its sensitivity on UVR in May, and (ii) altitudinal spreading of brown-tail moth population up to 800 – 1000 m. This research indicates that in situ forest observations in Serbia are not only affected by climate change, but also by the combined effect of climate on forest pests. For further research, we recommend exploring other forest stressors or dieback phenomena in European forests by applying the same or similar regional climate model dataset.

Beryllium-7 is a natural radionuclide used as a tracer of the stratospheric-tropospheric exchange. Its abundance in the surface air is expected to change as the temperatures in the atmosphere increase. To investigate the temporal trends of the beryllium-7 activity concentrations and temperature, we apply spectral analysis to time series from three sampling sites: Belgrade in Serbia, and Ljubljana and Krško in Slovenia. The sites lie close to the 45 ºN parallel, with Krško approximately 400 km and Ljubljana around 500 km west of Belgrade. Between January 1991 and December 2019, the air filter samples were collected using air samplers; a monthly composite sample was formed and analysed by gamma spectrometry. We use monthly mean temperature records from the European Climate Assessment & Dataset, the Republic Hydrometeorological Service of Serbia for Belgrade, and the Slovenian Environment Agency for the sites in Slovenia. In the spectral analysis decomposition, we look into a term called trend that represents the overall growth (increase or decrease) in the data records. The trend is calculated using a linear fit. All three sites show 1) positive temperature trends, however statistically insignificant (at the 95 % confidence level), and 2) statistically significant beryllium-7 activity concentration trends of 2.26 %/year, 1.13 %/year, and 0.50 %/year in Belgrade, Ljubljana, and Krško, respectively. The results confirm our initial hypothesis–over the 28 investigated years, the beryllium-7 activity concentrations increase in the surface air. On the other hand, the non-significant temperature rise in our records suggests that within our method, the temporal resolution of one month is insufficient for obtaining a statistically significant temperature trend.

This study aims at analysing the latitudinal variability of both the yearly and seasonal pattern of 7Be surface activity concentrations, at addressing the impact of tropopause height (TPH) on 7Be distribution and at evaluating the time lag between TPH and 7Be at European level. With this aim, weekly 7Be and daily TPH data at 17 sampling stations during 10 yr (2001–2010) are analysed. 7Be shows a clear increasing tendency in the period and generally tends to increase with decreasing latitude. The seasonal pattern generally shows maxima during the warm period and minima during the cold one. The seasonal variogram analysis points out a good spatial correlation for TPH data while a weaker one is observed for 7Be, having TPH a larger influence on 7Be during summer. The influence of TPH on 7Be exhibits a large spatial variability, with a clear gap between south and north in the area of the polar front jet. The results identify the presence of two main groups, in particular separating between stations located in northern Europe (50 °N and higher) and stations in southern Europe (south of 50 °N). A similar behaviour for stations located in the same geographical area is also observed when looking at the day of maximum impact of TPH on 7Be concentrations. The results suggest that 7Be concentrations respond in different time ranges to changes in the TPH, observing seasonal differences in each group. These results represent the first European approach to the understanding of the TPH impact on 7Be concentrations at surface levels.Keywords: 7Be, radiotracers, tropopause height, transport time, seasonality, Europe(Published: 11 May 2016)Citation: Tellus B 2016, 68, 29534, http://dx.doi.org/10.3402/tellusb.v68.29534

Intense direct and indirect human pressure has been imposed on grasslands throughout their range. Mostly due to the constant need for more food production or due to changes in environmental conditions, grasslands as habitats are expected to become highly endangered. The aim of this study was to estimate the grasslands’ ecological response to future climate and environmental changes. The study took place in three ecologically different grassland communities in three protected natural areas of Serbia (Southeastern Europe), following the same methodology. The study sites were: 1) Peštersko polje Special Nature Reserve (SNR), 2) Deliblato sands SNR (its southern part: Labudovo okno) and 3) Zasavica SNR. Climate change was simulated for mean temperatures and precipitations using the Eta Belgrade University-Princeton Ocean Model (EBU-POM) climate model, for the A1B Intergovernmental Panel on Climate Change (IPCC) emission scenario covering the 1951–2100 period and insolation and volumetric soil moisture content for the 1979–2100 period. Grassland vegetation was analysed at all three sites. One representative plant community per site was selected for further analysis and simulation of ecological changes. One plot was positioned inside each of the above-mentioned communities, all vascular plant species inside the plot were recorded, and soil samples were taken. Ecological Optima (EO) for moisture and temperature were calculated from modified Ellenberg’s plant indicator values of recorded species. The plants’ response to climate and environmental changes was simulated using the VSD+ model for the 2010–2100 period. The data obtained from the model were further analysed with Canonical Correspondence Analysis (CCA). Overall results show that the temperature rise, along with the irregular precipitation at all three sites, will lead to a drop of the relative abundance of many native species in the period between 2040 and 2060. The low obtained Habitat Suitability Index for the future means that there will be either unfavourable environmental conditions for the development of grasslands, or the species we analysed were untypical. Cosmopolitans and xerothermic species will be more accustomed to the new conditions. Grasses will be the most resilient functional group according to our study. It may be concluded that the functional group of grasses will also play the leading role in future grasslands at the studied sites. In Serbien sind vor allem natürliche Grasländer stark gefährdet. Bislang liegen nur sehr wenige Studien zur Auswirkung von Klimaveränderungen auf Grasländer in Serbien vor (z. B. BELOICA et al. 2015). Zudem wurde die Biodiversität des Graslands in Südosteuropa bislang insgesamt kaum untersucht (DENGLER et al. 2014). Das Ziel dieser Studie ist ein Beitrag zur Kenntnis, inwieweit Pflanzengesellschaften auf veränderte Klimabedingungen reagieren. Die Untersuchung wurden in drei Schutzgebieten in Serbien durchgeführt; untersucht wurden drei ökologisch verschiedene Graslandgesellschaften. Die drei Untersuchungsgebiete waren das Peštersko polje-Special Nature Reserve (SNR), das Delibater Sande-SNR (dessen südlicher Teil zum Gebiet Labudovo okno gehört) und das Zasavica-SNR. Zunächst wurde die Graslandvegetation der drei Gebiete analysiert. In jedem Gebiet wurde eine repräsentative Pflanzengesellschaft ausgewählt um die ökologischen Veränderungen zu simulieren. Die ökologischen Optima der Arten hinsichtlich Feuchte und Temperatur wurden auf Grundlage von Zeigerwerten (nach KOJIĆ et al. 1997) berechnet. Die Bodeneigenschaften wurden an den gleichen Orten bestimmt, wo die Aufnahmen erstellt wurden. Die Namen der Pflanzenarten entsprechen der EURO+MED-Datenbank und die Habitattypen EUNIS. Die Veränderungen der mittleren Temperatur und des mittleren Niederschlags nach dem A1B-(IPCC 2014)-Szenario wurden auf Grundlage des Zeitraums 1951–2100 mit Hilfe von EBUPOM-Klimamodellen simuliert. Die Einstrahlung und der volumetrische Bodenwassergehalt wurden auf Grundlage des Zeitraums 1979–2100 simuliert. Die Reaktion der Pflanzen auf die Klima- und Umweltveränderungen wurde mit Hilfe von VSD+ (Version 5.5, 2001, 2015 Alterra, CCE; MOLDIJKSTRA & REINDS 2017) für den Zeitraum 2010–2100 simuliert. Eine kanonische Korrespondenzanalyse der Pflanzengesellschaften für denselben Zeitraum wurde mit Hilfe von Past 3.14 (HAMMER et al. 2001) durchgeführt.