engleski

Bird species that have significantly changed breeding range on Croatian coastal area: comparison of 30 years old data and recent knowledge

In Croatia there are tenths of bird species that are known to have changed breeding range and/or abundance in the last decades. Comprehensive research had been undertaken from 1946 to 1975 on the Croatian coast. In that research representative data for 106 breeding bird species were collected. We compared those distribution data to data we collected in the recent years and tried to evaluate potential reasons for changes. For a number of species we noticed the difference in breeding range and/or abundance and for 16 species a significant change was recognized. For other species the change was not clear giving the possible difference in methodology or research effort. Thirteen species have shown positive trend increasing breeding abundance in research area (two species) or increasing breeding range (eleven species). Of the second group of species four species expanded their breeding range into colder habitats and seven species into warmer habitats. Three species have shown negative trend with decreasing abundance or becoming locally extinct. Potential driving forces for positive trend are as followed: reforestation alone, reforestation together with less disturbance, agricultural changes and climate change. Reforestation is due to abandoning rural settlements (this also means less disturbance), decreasing extensive livestock keeping and extensive afforestation. Another possible reason is constant decrease in pressure of illegal hunting and trapping on Croatian coast. For at least one species one of the reasons for increase is change in species behavior and breeding biology. The reasons for decline of three species are habitat loss due to reforestation (Short-toed Lark) and reforestation combined with increased hunting pressure (Rock Partridge) and agricultural changes (Little Owl and Rock Partridge). These species are also decreasing in other parts of Europe. Approach that we have applied is a good indicator for trends of species we had enough available data, and could be a starting point for future monitoring. This is especially important for species declining globally but also for the species that are increasing their numbers as they could be a potential competitors with endangered species.

birds Croatia breeding range change

nije evidentirano