Andrzej Bytnerowicz, Stanislaw Małek, Ovidiu Badea, Hana Pavlendova, Tibor Priwitzer, Diana Silaghi
State of Science
Globally, ozone (O3) is the most phytotoxic air pollutant with predicted negative effects on vegetation worldwide (Ainsworth et al., 2012). In the Carpathians O3 concentrations are characterized by high spatial and temporal variability. Highest O3 concentrations in the Carpathians occur in the southern Slovakia with concentrations which have not significantly changed over the last 20 years (Hana Pavlendova, personal communication, 2014). Also in the Czech Republic elevated O3 concentrations persist in many mountain ranges, including the Moravskoslesky Beskid Mountains (Northwestern Carpathians). In those highly exposed areas, O3 maximum hourly concentrations may reach 90 – 100 ppb (Bohumir Lomsky and Vit Sramek, personal communication, 2013). In the Slovak Carpathians the O3 exposure doses considered safe for sensitive vegetation (AOT values <10,000 ppb h for forest trees) often were reaching ~30,000 ppb h until 2007. However, recently recorded values have been significantly lower (Hana Pavlendova, personal communication, 2014). In the last two decades, the lowest O3 levels (summer average less than 40 ppb) occurred in the Retezat Mountains of the Romanian Southern Carpathians (Silaghi and Badea, 2012). Nevertheless, in these mountains in the last 15 years an increasing trend of O3 concentrations was observed (Silaghi, 2013). During the same period in other Southern Carpathian ranges, the Bucegi and Piatra Craiului Mountains, higher (summer averages higher than 40 ppb) and stable O3 levels were recorded (Silaghi et al., 2013; Diana Silaghi, personal communication, 2014). Red-fruited elderberry (Sambucus racemosa) is the most common and reliable shrub indicator while Swiss stone pine (Pinus cembra) is a sensitive tree indicator of O3 phytotoxic effects (Manning, 2005).
Sulfurous and nitrogenous air pollution and deposition
Significant reductions of SO2 concentrations, S deposition and the SO4/NO3 deposition ratio have been observed for about 20 years in the Carpathians. Example from the Slovak Carpathians shows S deposition decreasing from ~13 kg S ha-1 yr-1 in 1997 to ~6 kg S ha-1 yr-1 in 2013 (Tibor Priwitzer, personal communication, 2014). During the 2006-2010 period, S and N deposition levels in Southern Carpathians (Bucegi Mountains) were low with mean values ranging between 2.4 – 7.9 kg S ha-1 yr-1 and 1.1 – 6.6 kg N ha-1 yr-1, respectively (Barbu et al., 2013). In the north-western Carpathians near the Polish-Czech border experiencing some of the highest levels of N deposition in Europe (~30 kg N ha-1 yr-1 in mid 1990s), present levels do not exceed 10 kg N ha-1 yr-1. At the same time there is an increasing importance of NH4+ over NO3– (Małek, 2010). Critical loads for nutrient N deposition in the Tatra Mountains have been exceeded both for forests and meadow ecosystems (Bowman et al., 2008). Current levels of N deposition inhibit plant growth in acid soils due to a loss of basic cations and increased toxicity of heavy metals in soil. These chemical factors together with changing climate, especially increasing temperatures and periods of drought, negatively affect Norway spruce stands and contribute to the observed bark beetle attacks and decline of forests in the western Carpathians. Air pollution in the southern Carpathians is generally lower than in the western Carpathians, as indicated by relatively low air pollution levels in the Romanian Carpathians (Badea et al., 2012). Significant improvement of forest health condition in Romania was observed in last 10 years and was attributed to increased precipitation combined with relatively low increase of ambient temperatures (Ovidiu Badea, personal communication, 2014). However, careful control of the Carpathian chemical environment is needed since even at relatively low levels of air pollutants and atmospheric deposition negatively effects on forest health and growth could take place due to interactive effects with other factors, such as extreme climatic events or pest and pathogens attacks.
The chemical composition of the Carpathian spring, stream and runoff water shows a great diversity as a result of geological structures and water-bearing horizon lithology and forest management (Żelazny et al., 2011). In addition, changes in discharge during flood events affect chemical characteristics of water and concentrations of various ions. Recent surface sediments in the high elevation southern Carpathian lakes in Romania showed elevated levels of selected heavy metals, probably affected by an increased atmospheric deposition of particulate matter from the long-range transport of polluted air masses.
Recommendations for future research:
(1) Develop common Carpathian Mountains monitoring system of air pollution (O3, NO2, SO2, NH3) and deposition (especially N, S, heavy metals). This could be done by expansion of the ICP Forests Level I and II plots.
(2) Efforts for evaluation of critical loads for N and S deposition and acidity as well as critical levels for O3 exposures should be continued and expanded.
(3) More extensive surveys are needed and a better understanding of the long-term ozone effects on plant growth and reproduction in relation to biodiversity should be obtained.
(4) Both ecosystem-level research and large-scale studies are needed to understand spatial distribution of N and S pollution and mechanisms of its impact on ecosystems, especially related to Norway spruce dieback.
(5) Water chemistry related to natural and anthropogenic processes across the Carpathians should be further investigated.
(6) Establish a centralized depository for the environmental chemistry monitoring data from Carpathians and recommendations for field and laboratory procedures.
(7) International research and monitoring collaboration between the Carpathian Region and other mountainous regions of Europe and North America should be expanded.
Ainsworth, E.E., Yendrek, C.R., Sitch, S., Collins, W.J. , Emberson, L.D. 2012. The effects of tropospheric ozone on net primary productivity and implications for climate change. Annu. Rev. Plant Biol., 63, 637-661.
Badea., O. Bytnerowicz, A., Silaghi, D., Neagu, S., Barbu, I., Iacoban, C., Iacob, C., Guiman, G., Preda, E., Seceleanu, I., Oneata, M., Dumitru, I., Huber, V., Iuncu, H., Dinca, L., Leca, S., Taut, I. 2012. Status of the Southern Carpathian forests in the long-term ecological research network. Environ. Monit. Asses., 184(12):7491-515.
Barbu, I., C. Iacoban, G. Guiman and C. Iacob. 2013. Chapter 3.7. Atmospheric Deposition and Soil Solution. In O. Badea(Eds.):Long-Term Ecological Researches on Representative Forest Ecosystems of Bucegi Natural Park. Ed. Silvica, Bucharest, pp 127-168.
Silaghi, D. 2013. Research on the state of forest ecosystems in Retezat National Park under the influence of atmospheric pollution and other stress factors. PhD Thesis, Transilvania University of Brasov, Romania.
Silaghi, D., O. Badea, S. Neagu, C. Iacob and G. Guiman. 2013. 3.6. Air Quality. In: O. Badea (Ed.):Long-Term Ecological Researches on Representative Forest Ecosystems of Bucegi Natural Park. Ed. Silvica, Bucharest, pp 119-127.
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