Catsadorakis G.,Society for the Protection of Prespa |
Onmus O.,Ege University |
Bugariu S.,Romanian Ornithological Society BirdLife Romania |
Gul O.,Ege University |
And 11 more authors.
Endangered Species Research | Year: 2015
The 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. © The authors 2015. Source
Gremillet D.,CNRS Center of Evolutionary and Functional Ecology |
Gremillet D.,University of Cape Town |
Nikolaou H.,Society for the Protection of Prespa
Aquatic Biology | Year: 2012
Great cormorant populations have shown near-exponential increase in Western Europe over recent decades, generating wildlife management conflicts across the region. It is essential to detail the foraging strategies of this piscivorous predator to understand the functional mechanisms determining its actual impact upon freshwater fisheries. Great cormorants have been shown to be highly efficient predators, yet their underwater vision is limited in turbid water. We therefore tested the hypothesis that the predatory performance of great cormorants will be lower in turbid than in clear water. We used parallel data sets on water turbidity, great cormorant diet, great cormorant population size, fish biomass and fish-cormorant co-occurrence collected over 3 decades, with a focus on 1997 and 1998, in 2 Macedonian lake systems with contrasting features. In one lake system, water turbidity was lower, fish abundance was also lower, and the local great cormorant population did not increase markedly in size. Local populations of Alburnus belvica, which is the preferred prey of great cormorants in this region, increased over the study period. In the second lake system, water turbidity was higher, fish abundance was also higher, and the local great cormorant population has increased exponentially since the 1980s. Along the highly turbid affluent of this lake, great cormorants foraged en masse at the time of highest fish abundance, and local fish biomass decreased over the study period. Overall, our data strongly suggest that great cormorants remain highly efficient fish predators even in the most turbid water. We propose that they switch from visual to tactile cues to maintain high foraging efficiency when diving in water above a certain turbidity threshold. © Inter-Research 2012. Source
Doxa A.,Institute Mediterraneen Of Biodiversite And Decologie Imbe |
Robert A.,French Natural History Museum |
Crivelli A.,Station Biologique de la Tour du Valat |
Catsadorakis G.,P.O. Box 403 |
And 4 more authors.
Auk | Year: 2012
Although changes in the mean arrival and breeding dates of some species are expected in response to climate change, other species may respond to direct or indirect climate effects by modifying the duration of their breeding period. We used a 20-year database for two closely related species that breed in sympatry in Europe, the short-distance migrant Dalmatian Pelican (Pelecanus crispus) and the long-distance migrant Great White Pelican (P. onocrotalus), to test for changes in breeding phenology over the past two decades. Median laying dates of the species covaried over time, indicating that the same or similar environmental factors probably influenced both species at their breeding sites. However, direct climate effects were revealed only for the shortdistance migrant species, which showed a rapid advancement in its median laying dates (1.4 days year-1). This shift was associated with (1) an increase in population size and (2) weather variation following warmer and wetter winters. Earlier breeding was associated with enhanced survival of juvenile Dalmatian Pelicans, especially during hot and wet years. The Great White Pelican exhibited no advancement in its median laying date, but it significantly reduced the duration of its laying period (1.7 days year-1) by advancing the latest laying date. Furthermore, the response of the Great White Pelican was related only to factors of population size. Further analyses of breeders' interactions within and between species might help to identify possible indirect effects of environmental changes on both species and should be further considered for their future conservation. © The American Ornithologists' Union, 2012. Source
Doxa A.,CNRS Science Conservation Center |
Doxa A.,University of Aegean |
Doxa A.,CNRS Mediterranean Institute for Biodiversity and Ecology Marine and Continental |
Theodorou K.,University of Aegean |
And 6 more authors.
Population Ecology | Year: 2012
Spatial synchrony in population dynamics has been documented recently across a range of taxa, and a number of hypotheses about the mechanisms driving spatial synchrony and the consequences of this phenomenon for the persistence of populations have emerged. Spatial environmental covariance is one of the principal factors influencing this synchrony on a large scale. However, most studies focus on population abundances, and little evidence exists on the spatial synchrony of demographic parameters. We used a 15-year dataset from two populations of a vulnerable bird species, the Dalmatian Pelican (Pelecanus crispus), to identify local and global environmental factors that cause population synchrony. We show that survival rates were temporally synchronised between the studied populations and that a large part (>50 % for both populations) of this covariation was driven by local environmental conditions. Several components of the North Atlantic Oscillation index were correlated with local climatic conditions, but not all of these components can be used as informative proxies for future variation in survival. We also present evidence that an individual's future survival can be strongly influenced by the conditions occurring during the early period of its life. Environmental factors such as water level and food availability had similar influences on breeding success and juvenile survival. Juvenile survival was lower during dry years and years of low food availability. This finding indicated that intra-specific competition may act as a limiting factor for species demography, especially in large populations. Estimating the strength of synchrony is important and should be considered in population and metapopulation analyses and in relationship to conservation measures. © 2012 The Society of Population Ecology and Springer. Source
Berrebi P.,Montpellier University |
Tougard C.,Montpellier University |
Dubois S.,Montpellier University |
Shao Z.,Montpellier University |
And 3 more authors.
International Journal of Molecular Sciences | Year: 2013
The Balkans are known to have a high level of biodiversity and endemism. No less than 15 taxa have been recorded in salmonids of the Salmo genus. Among them, the Prespa trout is found in only four river systems flowing into Lake Macro Prespa, three in the Former Yugoslav Republic of Macedonia and one in Greece. This is the first comprehensive survey of all streams located within the Macro Prespa Basin, encompassing the whole taxon range. A large genetic sample of 536 Prespa trout was collected mainly between 2005 and 2007. The sampling included 59 individuals from the Golema river system, 93 from the Kranska, 260 from the Brajcinska, 119 from the Agios Germanos, and five individuals from the lake itself. These specimens were analyzed with six microsatellite markers and by sequencing the mitochondrial control region. Nuclear data were examined through multidimensional analysis and assignment tests. Five clusters were detected by assignment: Golema, Kranska, Brajcinska upstream, Rzanska Brajcinska tributary and Brajcinska downstream. Most of these river systems thus hosted differentiated Prespa trout populations (with past gene flows likely dating before the construction of dams), except Agios Germanos, which was found to be composed of 5% to 32% of each cluster. Among the five trout individuals from the lake, four originated from Kranska River and one was admixed. Supported parsimonious hypotheses are proposed to explain these specificities. Conservation of this endemic taxon should take these results into account. No translocation should be performed between different tributaries of the lake and preservation of the Brajcinska populations should address the upstream-downstream differentiation described. © 2013 by the authors; licensee MDPI, Basel, Switzerland. Source