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Zagreb, Croatia

Sver L.,University of Zagreb | Bielen A.,Gekom Ltd. | Krizan J.,Oikon Ltd | Guzvica G.,Geonatura Ltd

The conservation of gray wolf (Canis lupus) and its coexistence with humans presents a challenge and requires continuous monitoring and management efforts. One of the noninvasive methods that produces high-quality wolf monitoring datasets is camera trapping. We present a novel monitoring approach where camera traps are positioned on wildlife crossing structures that channel the animals, thereby increasing trapping success and increasing the cost-efficiency of the method. In this way we have followed abundance trends of five wolf packs whose home ranges are intersected by a motorway which spans throughout the wolf distribution range in Croatia. During the five-year monitoring of six green bridges we have recorded 28 250 camera-events, 132 with wolves. Four viaducts were monitored for two years, recording 4914 camera-events, 185 with wolves. We have detected a negative abundance trend of the monitored Croatian wolf packs since 2011, especially severe in the northern part of the study area. Further, we have pinpointed the legal cull as probable major negative influence on the wolf pack abundance trends (linear regression, r2 > 0.75, P < 0.05). Using the same approach we did not find evidence for a negative impact of wolves on the prey populations, both wild ungulates and livestock. We encourage strict protection of wolf in Croatia until there is more data proving population stability. In conclusion, quantitative methods, such as the one presented here, should be used as much as possible when assessing wolf abundance trends. © 2016 Šver et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source

Spiric Z.,Oikon Ltd
Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering

Since 1995 the concentrations of total mercury were analyzed in the pheasant organs (liver, kidney, brain and muscle) that live freely in an area that was exposed to elevated levels of mercury as a result of industrial activity (mercury contaminated natural gas production and processing which began in 1980). The range of the median mercury concentration values (wet weight) in pheasant organs in Podravina, Croatia were 0.0004-0.024, 0.0001-0.034, 0.0002-0.016 and 0.0001-0.025 μg/g for liver, kidney, brain, and muscle, respectively. Results of these studies confirms that in the study area in the observed period there was no significant mercury contamination which can be linked to anthropogenic activities (hydrocarbon production) On the contrary, systematic measurements demonstrate a small but constant (barely noticeable) decline in mercury concentrations in pheasant's organs. Primarily, this is the result of the significant improvement in the technological process which involves the removal of mercury from the natural gas that was designed and implemented in 1993. However, due to the need for reliable control of mercury contaminated natural gas production and the importance for better understanding of long-term exposure to low levels of mercury, and assessment of their possible harmful effects on the environment, human and animal health, research will be continued. © 2013 Copyright Taylor and Francis Group, LLC. Source

Spiric Z.,Oikon Ltd | Srebocan E.,University of Zagreb | Crnic A.P.,University of Zagreb
Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering

In the last two decades (1990-2008), as part of a comprehensive monitoring of the eco-system, hares were collected in the vicinity of the mercury contaminated natural gas production and treatment plant Molve, Croatia. Their organs (muscle, liver, kidney and brain) were analyzed for total mercury concentration by cold vapor AAS. The range of the median mercury concentration values (wet weight) in hares organs were 0.001-0.005, 0.007-0.045, 0.022-0.126 and 0.0006-0.015 μg/g for muscle, liver, kidney and brain, respectively. The results of mercury measurements in hares organs during the period of last twenty years demonstrate a small but constant decline in concentration values. Comparing the results obtained in this study with results published in available data and literature on mercury concentration in hare's tissue it can be concluded that area investigated in this research belongs to low mercury contaminated region. Nevertheless, further eco-monitoring and mercury measurements in various hares organs are valuable and necessary and will be continued. © 2012 Copyright Taylor and Francis Group, LLC. Source

Recurrent climate-induced mass mortalities of marine animals have been recorded in the Mediterranean Sea over the past 15 years. These mortality outbreaks have been associated with positive thermal anomalies. In this study, we assessed long-term (from 2003 to 2013) responses of the temperate coral Balanophyllia europaea to increasing seawater temperatures in the Mljet National Park in the Adriatic Sea (Northern Mediterranean Sea) and described the relationship between recurrent mortality events and sea temperature regimes in the southern Adriatic Sea. Our results indicate that polyp bleaching and tissue necrosis caused the observed mortality. The first observations of B. europaea mortality within the study area in the Mljet NP were in early September 2003. The Mediterranean area experienced high temperatures and hydrographic stability over a period of several weeks throughout that summer, which resulted in a mass mortality event. In the Mljet National Park, the highest impact of mass mortality started during the exceptionally hot summer of 2012, representing one of the most severe mass mortality events ever observed in the Adriatic Sea. In 2012, sea temperatures at a 5 m depth during the summer period (from June to September) ranged from 24.44 to 30.16 °C in the Mljet NP. The northern sites in the Mljet NP were highly impacted, with up to 80 % of B. europaea specimens affected by necrosis, while the southern sites displayed the highest impact, with 90–100 % of affected individuals. Without any coral adaptation to warming and under the present climate-warming trend, new mass mortality events may occur in the near future, possibly causing a major coral biodiversity crisis in the Mediterranean Sea. © 2014, Springer-Verlag Berlin Heidelberg. Source

Spiric Z.,Oikon Ltd | Stafilov T.,Ss. Cyril and Methodius University of Skopje | Vuckovic I.,Ss. Cyril and Methodius University of Skopje | Glad M.,Teaching Institute of Public Health
Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering

During the summer and autumn of 2006 moss samples were collected from 98 sampling sites evenly distributed all over the territory of Croatia. Moss sampling was repeated in 2010 when additional sampling sites were added and a total of 121 samples were collected. Kjeldahl method was used to determine the nitrogen content in the samples. Descriptive statistics and distribution maps were prepared. Data obtained from these two surveys were compared, and additional comparison was done with data obtained from similar studies in neighbouring countries and Finland as a clean area. The median value of N content in the samples collected in 2006 is 1.60% and varies from 0.79% to 3.16%. The content of N in samples collected in 2010 ranges between 0.71% and 2.93% with the median value of 1.49%. High contents of N (2.32% - 3.17%) were found in the regions of Slavonia, Podravina, Posavina and cities Zagreb and Sisak as a result of agricultural activities, industry and traffic. Copyright © 2014 Taylor & Francis Group, LLC. Source

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