engleski

Atmospheric deposition and ozone levels in Mediterranean forest ecosystem of Croatia

Mediterranean forest ecosystems in Croatia are highly significant and cover almost half of Croatian total forest area. They provide multiple goods and services largely related to their environmental and social functions. Those forests are ecologically very sensitive, because of its geographic position, complex orography, specific meteorological conditions and number of pollution sources. Among all bioclimatic regions, Mediterranean region appears to be the most vulnerable to global change. The vulnerability of climate change is related to the trend if increasing temperature, degradation of water resources and increased of water demand. Furthermore, it is the region at the highest ozone risk as ozone formation occurs at high temperatures in presence of solar radiation, which is elevated in the Mediterranean –type ecosystems. Ozone as accompanying agent of climate change is also among key factors resulting in spatial and temporal changes in tree crown condition and productivity. Therefore, the reach of ozone levels and visual symptoms was necessary. The concentrations were measured with ozone passive samplers. Samplers were put in open field close to forest. Samplers were collected bee-weekly from April to September. Annual means of ozone concentration was calculated and they were used as an indicator of possible stress due to ozone. Many plants species respond to elevated ambient levels of ozone with distinct specific foliar/needle symptoms. In order to detect effects of ambient ozone concentration on crown condition, ozone included visible injury on leaves and needles were assessed on the plots. Sypltoms suggesting oxidative stress caused by high ground-level ozone concentrations along Croatian Adriatic coast were found at Poreč LESS on Ligustrum vulgare, Pinus halepensis and Cornus mas. Possible symptoms were also recorded at LESS Muć on Clematis vitalba and at Šišan on Fraxinus ornus and Laurus nobilis. No symptoms were found on LESS Vransko lake.

Croatia, Mediterranean forest ecosystems, ozone levels, visible injury

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