Premigratory ecology, phylogeography and conservation genetics of the threatened raptor falco naumanni in the Balkans (Doctoral thesis)

Μπούνας, Αναστάσιος


New and integrative approaches for the conservation of mobile species are becoming increasingly needed recently, as the genetic component is often overlooked by international conservation policies while management schemes that consider the different stages of a species life cycle and the genetic characteristics of populations are scarce. Such an approach is attempted in this thesis, targeting the migratory bird species, the Lesser Kestrel (Falco naumanni). The Lesser Kestrel is a small migratory falcon breeding in the southern part of the western Palearctic, from the Mediterranean and the Middle East to central Asia, the Mongolian steppes and China while wintering in sub-Saharan Africa. The species went through a sharp decline in its European populations in the 1950s, due to the intensification of agriculture, land-use change and the subsequent habitat degradation. This decline led to the complete extinction of many populations as well as and the loss of several colonies in some countries. Today, the overall European population seems to have stabilized due to the management actions that have taken place over the past decades, mainly on the Iberian Peninsula. However, in central and eastern Europe, where the species exhibits a fragmented distribution, it is considered to be population-depleted and thus in need of conservation concern.In the present thesis, genetic and ecological data are used to: a) describe, analyze and interpret the spatial patterns of genetic diversity and the structure of the Lesser Kestrel populations; and b) highlight the importance of pre-migratory areas as important centers for the conservation of the species. The ultimate goal is to produce knowledge that will contribute to more effective planning of conservation actions and management strategies for the species in the Mediterranean region.In order to describe the pre-migratory concentration of Lesser Kestrels in the city of Ioannina, count data for the years 2000-2015 were used. Also, the trees used by the species for roosting were identified during this period. The peak of the pre-migratory concentration of Lesser Kestrels in the city of Ioannina takes place in August and lasts 20 days. This gathering occurs on an annual basis, whereas the large number of birds (nearly 3000 individuals) suggests that it is not a local phenomenon, but birds from other breeding colonies visit the city. The Lesser Kestrels gathering in the area were found to use exclusively Platanus orientalis as roosting trees.In the attempt to clarify the migration patterns of the species on the Balkan peninsula, citizen-science data were retrieved and analyzed. In addition, the examination of ringing recoveries allowed for the assessment of the degree of philopatry and possible pre-migratory movements of the species in region. The species was found to migrate in a broad-front during spring, from March to the beginning of May, while in a slightly narrower front during autumn from August to early October, contrary to the migration strategy of birds from the Iberian Peninsula. Adult Lesser Kestrels showed strong philopatric behavior, while juvenile birds dispersed over long distances, in some cases up to 900 kilometers.The locally increased availability of food resources, that is one of the main drivers of the pre-migratory concentrations, was approached by a comparative diet analysis between the breeding and pre-migratory period using regurgitated pellets. The Orthoptera were found to be the main prey consumed by the species both during breeding and pre-migration. However, during the breeding season, the species exhibits a mixed feeding strategy with a broad niche width, while during the pre-migration the Lesser Kestrel’s feeding strategy appears to be specialized to Orthoptera and specifically towards Acrididae. The study implicitly showed that the non-fragmented dry grasslands around the city of Ioannina are perhaps the most important habitat used by the species during the breeding season. In contrast, during the pre-migration period, the mountainous areas around the city (more than 20 km away) are of high importance for the species as they retain a high abundance of Orthoptera.In order to assess the levels of genetic diversity and to investigate the spatial patterns of the species genetic structure, 295 samples were collected from 15 natural populations within its distribution range. The molecular markers used were 18 microsatellite loci. The results of the analyses confirm the phylogenetic pattern according to which the European and Asian populations of the species are significantly differentiated, while the population of Israel appears genetically mixed. The available data suggest that the population of Limnos may have been formed by Lesser Kestrels of Asian origin. The core populations have been found to maintain high levels of gene flow with some of the smallest peripheral populations, while peripheral populations showed reduced connectivity among them. Populations of the species in the Mediterranean seem to have been affected differently by the great historical decline as three of the peripheral populations of the central and eastern Mediterranean have been found to show signs of bottlenecks whereas the rest maintain high levels of gene flow with the central populations avoiding any bottleneck effects despite the reduction in their size.To investigate the origin of birds gathering in pre-migratory areas, 146 feathers were collected and genotyped from the two largest pre-migratory roosts of the species in the Balkans: the city of Ioannina and the Drinos valley in southern Albania. Assignment tests based on microsatellite genotypes were performed for nine reference breeding populations. The Lesser Kestrels that visit the city of Ioannina during pre-migration come from at least six different breeding populations of the species for which genetic data (genotypes) were available. Further spatial modeling of allelic frequencies showed that individuals may also originate from five additional populations. It appears that pre-migratory concentrations play an important role in shaping the genetic structure of populations as they attract individuals that could potentially breed in the respective regions.Finally, the results and conclusions of this study can be used for the design of an effective conservation strategy for the species in the Mediterranean region. Such an integrative approach allows for the implementation of targeted management practices and constitutes a cost-effective strategy for the recovery of the populations of the species.
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών Υγείας. Τμήμα Βιολογικών Εφαρμογών και Τεχνολογιών
Subject classification: Οικολογία
Keywords: Οικολογία,Γενετική πληθυσμών,Κιρκινέζι,Προ-μετανάστευση,Βαλκάνια,Ecology,Population genetics,Premigration,Lesser Kestrel
URI: http://olympias.lib.uoi.gr/jspui/handle/123456789/29218
Appears in Collections:Διδακτορικές Διατριβές

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