Site fidelity and determinants of wintering decisions in the Dalmatian pelican (Pelecanus crispus)

Wintering site selection is a major decision in a bird's annual life cycle since conditions experienced by individuals within a wintering site can influence individual fitness and ultimately population dynamics. If individuals show strong fidelity to specific sites, annual environmental effects can be reinforced. In this study we analyse winter resightings of ringed Dalmatian pelicans, collected during a 35-year-long ringing survey, to identify winter movement patterns of Dalmatian pelicans, assess the level of site fidelity both within and among consecutive wintering events and examine environmental factors that may contribute to an individual's decision to move towards a specific site during the winter period. Our results showed that the decision of Dalmatian pelicans to move towards a specific site was mainly driven by the site's size and temperature conditions. Larger wetlands can provide birds with higher resource abundance and offer more opportunities to exploit optimal roosting and feeding habitats, whereas wetlands that do not freeze during the winter are a definite requirement. Wintering movements were more likely to occur at short distances from a bird's natal colony, whereas it was uncommon for birds born in wetlands located in the Adriatic and Ionian coast to move eastwards during the winter, suggesting a level of spatial substructure. Furthermore, we showed that the species exhibits very strong within-year and among-year wintering site fidelity, with birds moving less during the winter, whereas juvenile birds travel greater distances than the rest of the age classes examined. Our conclusions could guide an effective approach to site-based conservation management at key wintering sites.The pelican ringing survey in south-eastern Europe (Dr A.J. Crivelli, project leader) has been supported by. The implementation of the present study was funded by the Society for the Protection of Prespa (SPP). The work of SPP on pelicans was funded by MAVA until 2018 and after that by the Prespa-Ohrid Nature Trust (PONT). The national scheme of Dalmatian Pelican ringing and ring reading activities in Turkey was supported by TUBITAK (project code: Turkiye Bilimsel ve Teknolojik Arastirma Kurumu KBAG-111T465). The work at Srebarna colony in Bulgaria was supported by Tour du Valat and Swarovski Optik.Society for the Protection of Prespa (SPP); Prespa-Ohrid Nature Trust (PONT); TUBITAK [KBAG-111T465]; Tour du Valat; Swarovski Optik; MAV

Temporal trends and determinants of fish biomass in two contrasting natural lake systems: insights from a spring long-term monitoring scheme

Freshwater fish declines are triggered by a suite of anthropogenic threats, including habitat degradation, climate and land use change, biological invasions, pollution and overfishing. Robust monitoring schemes are needed to understand and detect any effects of different factors on freshwater fish abundance and to be able to predict and respond to potential stressors. Here, we used standardized biomass-per-unit-effort (BPUE) data deriving from gillnet sampling over a 34-year period in the two Prespa Lakes and determined species trends using general additive models coupled with structural change models. Furthermore, the influence of seven environmental variables was assessed for each fish species using an analytical approach based on random forests. We showed that the total annual BPUE is increasing in Lake Mikri Prespa whereas it is stable in Megali Prespa and that the relative BPUE of introduced species in the former is increasing through the years. Differences in the lakes' trophic status were reflected in species trend patterns. Random forests showed that air temperature, the introduction of the invasive Lepomis gibbosus, predation and water management played a role in shaping species biomass in Mikri Prespa whereas abiotic factors are the main drivers of biomass changes in Megali Prespa. Our results provide empirical evidence on the importance of long-term monitoring in distinguishing between direct and indirect effects of large-scale stressors on fish abundance as well as insights towards sustaining the integrity of fish communities

Current status of the Dalmatian pelican and the great white pelican populations of the Black Sea/Mediterranean flyway

WOS: 000353916400003The Dalmatian pelican (DP) Pelecanus crispus and the great white pelican (GWP) Pelecanus onocrotalus are listed as 'Vulnerable' and 'Least Concern', respectively, in the IUCN Red List. We present an updated estimation of the Black Sea/Mediterranean flyway population status of both species, based on data provided by experts working in all 7 countries of the region where pelicans breed and/or overwinter, who came together at the 1st Workshop on Pelican Research and Conservation in Prespa, Greece. The DP breeding population in the Black Sea and Mediterranean countries increased from 1730-2105 pairs in the years 2000-2010 to 2154-2437 pairs in 2011-2012. Approximately 40% of the Palaearctic breeding population of GWP occurred in Southeast Europe and Turkey. In 2011-2012 the GWP population in this region was estimated to be 4702-5175 pairs, and has remained more or less stable during the last decade. Although all the breeding sites for both species are in protected areas, disturbance at nesting places was considered to be the main threat. Direct persecution and electric power lines still cause occasional problems. In deltaic lagoons, erosion and inundation of nesting sites cause breeding failures in DPs, while in inland wetlands large water level fluctuations are a widespread problem. Decrease of fish stocks is a threat, especially in coastal areas. Many stop-over wetlands along GWP migration routes between Southeast Europe and Africa have been seriously degraded or have disappeared, resulting in serious implications for their populations. Conservation needs are listed, but further research is recommended for both species.TUB TAK research projectTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [111T465]; ECEuropean Commission Joint Research CentreEuropean Community (EC) [LIFE05 NAT/RO/000169]; Swarovski Optik; Station Biologique de la Tour du Valat through the Foundation 'Le Balkan'; MAVA Foundation through the Society for the Protection of Prespa; Station Biologique de la Tour du Valat; Society for the Protection of Prespa; WWF GreeceTaej Mundkur, Nyambayar Batbayar, Piotr Cwiertnia, Andrej Vizi, Gennady Molodan, Simba Chan, Menxiu Tong, Zinovey Petrovych and Giannis Roussopoulos are thanked for providing unpublished information and/or for comments on an earlier draft. The Hellenic Ornithological Society provided International WaterBird Census data for both species in Greece. The work of M.S., O.O. and O.G. in Turkey was funded by a TUB TAK research project (No. 111T465). The conservation and monitoring activities in Romania between 2005 and 2009 were co-funded by the EC through the project LIFE05 NAT/RO/000169. The work in Srebarna was funded by Swarovski Optik and the Station Biologique de la Tour du Valat through the Foundation 'Le Balkan'. The work in Prespa, Am vrakikos and Kerkini in Greece was funded by the MAVA Foundation through the Society for the Protection of Prespa and the Station Biologique de la Tour du Valat, and G.C. was supported by the Society for the Protection of Prespa and WWF Greece. D. Tommy King, Dan Chamberlain, Hans Kallander and an anonymous re viewer made many useful suggestions that improved an earlier draft. Julia Henderson corrected our gross mistakes in the use of the English language