Andreja Radovic

Authors researched the habitat changes on specific habitat types on area previously assessed as the most important areas in Croatia for the protection of endangered bird fauna during 1990-2000 year period. The areas used in the analysis were four areas in continental part of the Croatia (Danube and Drava River alluvium, Pokupsko depression, Sava River basin, Upper Drava River basin) and four areas in the Mediterranean part (Neretva River estuary, NW part of the North Dalmatia, Pasko field, Lake Vrana). For the analysis of changes in classified habitat types Corine Land Cover Databases for 1990 and 2000 years were used. We used to assessment of the ornithological of the whole territory of Croatia according known distributions of endangered birds (Radovic et al. 2003). Using software package ArcView (Version 9.1, Copyright © 2006 ESRI) we abstracted the polygons with detected change in habitat class from period 1990 – 2000, further analysis was performed with SAS [JMP] software (Versi...

ABSTRACT Resource allocation within the replacement clutch: do female European starling (Sturnus vulgaris Linneus) adjust their reproductive strategy after a full clutch loss?. // Current Science. (2014) (prihvaćen za objavljivanje). URL link to work

ABSTRACT Ornithological data, in comparison to data for other biological groups, is often regarded as one that is most easily obtainable and birds are among best known organisms. Additionally, birds are indicators of environmental changes and good surrogate for ecological value of an area. For that reason, in Europe, data on birds and habitats are used as main pillars to advocate the conservation of nature in whole, through the Bird’s and Habitat’s Directives. Number of scientific and non-governmental organisations developed variety of monitoring programs in order to resolve questions on bird distributions, population statuses and diverse population parameters. Some Western European countries and North America, this period in time regard as time “beyond data gathering” where the usage of novel statistical techniques developed, enables us to answer more complex ecological questions that was not possible in the recent past. In the same time, vast amount of available remotely sensed data opened possibility to monitor bird habitats on a large scale, and more useful planning of corridors and stop-over sites as well as facilitate multispecies management. However, the situation in Croatia and neighbouring countries is far from described one. Extreme lack of bird data collected adequately through the time and space disables scientists to answer diverse ecological questions and detect changes in the environment. This is especially pronounced for territory keeping bird species for which only data on presence/absence can be found in EBCC Atlas of European Breeding Bird at 50 km resolution. Lack of experienced ornithologist resulted in lack of local breeding/wintering bird atlas on at least 10 x 10 km resolution. We propose a way of analysing data on passerine bird communities obtained from transect studies where only coordinates on start and end point of transects are available with total number of territory keeping species, which is often the case with ornithologists/birdwatchers in the region. Automation procedure via R script is prepared to do the following procedures: 1) check the date from which bird data are available and adjoining corresponding environmental predictors; 2) link start and end points according to transect code substitute real transects with straight line start-end points transect; 3) split data according to the transect code and create KML and Shapefile for check and validation; 4) prepared a set of environmental variables at 30 m resolution (e.g. elevation, slope, aspect, distance to the coastline, climate variable and Corine Land Cover or alternatively habitat classes if appropriate habitat mapping has been made for the area of interest); 5) extract information on environmental conditions along transect line using line profiles; 6) testing for all possible combinations of models and selecting the one that suits the best to the data according to Akaike Information Criterion and 7) make spatial prediction on counts according to the best subset model using regression or regression-kriging technique. In the future we will test performance of this type of approximate transects with real ones on the areas where data will allow, and detection of bird guilds where technique performs the best.

Decrease the number of cattle on pastures in the interaction with other environmental disturbances, act as a trigger to accelerate the invasion of certain plant species. One of these, invasive, species is Amorpha fruticosa L.. Field research of how A. fruticosa (ragweed) influence community structure of birds within the Nature Park, were conducted at five levels of ragweed density. The study attempts to answer the question: how the importance of open habitats is changed(grasslands and agricultural areas) for the conservation of birds in areas under this plant species invasion, and to what extent the spread of invasive species impacted bird species of special importance to the protection at the European level (SPEC species). The fieldwork was conducted during 2010 and in 2011 year. We recorded 102 species of birds that use researched habitats as nesting, feeding and/or resting place during migration. The strongest effect of Amorpha is detected on species that uses habitats of interes...

QuestionWhat are the woody vegetation encroachment patterns after agricultural land abandonment? Focusing on two parameters, woody plant species richness and vertical vegetation heterogeneity (number of different vegetation strata and their relative cover) we investigated: (a) the effect of forest encroachment following land abandonment; (b) the comparative importance of forest encroachment vis‐a‐vis topographic and climatic parameters, and finally; (c) the ecological importance of eight land‐cover types encountered in abandoned agricultural landscapes.LocationThe Balkan Peninsula (Albania, Bulgaria, Croatia, Greece).MethodsWe set up a standard methodology for 1 × 1 km site selection (70 sites) and data collection within 497 plots, along a well‐defined forest encroachment gradient that reflects land abandonment in terms of woody vegetation cover.ResultsThe pattern that emerged was neither clear nor common for the Balkan region, regarding the effect of forest encroachment on the wood...

The paper describes impacts of the main ecological factors on the development of horse fly populations in the alluvial floodplains of the Danube River in the Pannonian plain. The study has been conducted from 2004–2009 in the four, water dependent, succession stages of alluvial forest communities of Kopacki rit wetlands. In total more than 23 000 adult horse flies of 22 species were collected by canopy traps that were placed annually during the flight season from May–September. The most abundant species during the study period were: Tabanus bromius with 47%, T. sudeticus with 17% and Haematopota pluvialis with 11%, respectively. Correlation analysis has confirmed the influence of the deviations from long-term average values in the temperature, precipitation and flood duration on the numbers of adult horse flies during the following year. A significant positive correlation has been found between spring and autumn precipitation and rainy seasons yielded more horse fly individuals the ...

Abstract Species-specific differences in dynamics of agonistic interactions may influence the outcome of interspecific competition and potentially contribute to competitive advantage of one species over another. In this study, we compared the dynamics of agonistic interactions of one of the most successful crayfish invaders of European freshwater ecosystems, the signal crayfish (Pacifastacus leniusculus) and the widespread native European species currently undergoing range expansion in Croatia and Europe, the narrow-clawed crayfish (Astacus leptodactylus). Comparisons between P. leniusculus pairs and the A. leptodactylus pairs demonstrated significant differences in frequency and duration of agonistic encounters: P. leniusculus dyads engaged in fewer fights, but their duration was significantly longer. In staged interactions between size-matched interspecific pairs, agonistic behaviour of P. leniusculus individuals translated into dominance over their A. leptodactylus counterparts. This indicates that the success of P. leniusculus in agonistic encounters with the native competitor might stem from its readiness to continue fighting for a longer time period, and could lead to ecological advantages during niche competition even when facing a successful native crayfish species.

Abstract Understanding land abandonment and the resulting changes in land cover provides data for suitable reaction to habitat and species losses this process brings. This study aimed to define land-cover types and their biodiversity, record spatio-temporal changes and detect the trajectories and magnitude of these changes. The study was conducted on the island of Molat in the eastern Adriatic Sea. Land cover was defined for different years (1910, 1959, 1986, 2006) using remote sensing and recent vegetation sampling. The obtained land-cover maps were used for spatio-temporal analysis of land-cover change. Open vegetation units of rocky grassland, mesophilous grasslands and farm land dominated in 1910, covering 90% of the island. The observed changes occurred in trajectories through semi-open towards closed vegetation. In 2006, closed vegetation dominated, covering approximately 70% of the island area. The overall land-cover change was extreme, occurring over 90% of the island surface. Biodiversity analysis was related to the present land-cover types and change trajectories, and showed a considerable decline of species richness towards closed vegetation types. All observed changes were correlated to island depopulation and land abandonment. Re-population and encouragement of agro-pastoral activities should reduce habitat and species loss in the process of secondary succession.

Background and Purpose: No previous field investigations have been conducted on the biology and ecology of the native population of golden jackals (Canis aureus L.) from Dalmatia. The object of this study was to determine the feeding habits of this poorly studied population. Materials and Methods: The diet composition of golden jackals from Dalmatia was examined by scat analysis. From winter 1995 to spring 1997, field visits were made every season to the golden jackal habitat on the Pelje{ac Peninsula in Dalmatia, Croatia and scats of golden jackals were collected (n=130). Scats were washed out, dried and sorted. Classification of components was made under appropriate magnification. Conclusions: Both animal and plant components were found. Scat included from one to four components. The highest frequency was found for mammals (50.3%) followed by fruit seeds and vegetables (34.1%), insects (29.5%), birds (including eggs; 24.8%), artificial materials (24%) and branches, leaves and gras...

Agricultural land abandonment is recognized as a major environmental threat in Europe, being particularly pronounced in south-eastern Europe, where knowledge on its effects is limited. Taking the Balkan Peninsula as a case study, we investigated agricultural abandonment impact on passerine communities at regional level. We set up a standard methodology for site selection (70 sites) and data collection, along a well-defined forest-encroachment gradient that reflects land abandonment in four countries: Albania, Bulgaria, Croatia and Greece. Regardless the different socio-economic and political histories in the Balkans that led to diverse land abandonment patterns in space and time, rural abandonment had a consistent negative effect on bird communities, while regional-level analysis revealed patterns that were hidden at local level. The general trends were an increase of forest-dwelling bird species at the expense of farmland birds, the decline of overall bird species richness, as well as the decline of Species of European Conservation Concern (SPECs) richness and abundance. Many farmland bird species declined with land abandonment, whereas few forest species benefited from the process. In conclusion, our results support CAP towards hampering rural land abandonment and preserving semi-open rural mosaics in remote upland areas, using a suite of management measures carefully tailored to local needs. The maintenance of traditional rural landscapes should be prioritized in the Balkans, through the timely identification of HNV farmland that is most prone to abandonment. We also suggest that coordinated transnational research is needed, for a better assessment of conservation options in remote rural landscapes at European scale, including the enhancement of wild grazers' populations as an alternative in areas where traditional land management is rather unlikely to be re-established.