47 research outputs found
Using genetic markers to unravel the origin of birds converging towards pre-migratory sites
No full textIdentifying patterns of individual movements in spatial and temporal scales can provide valuable
insight into the structure of populations and the dynamics of communities and ecosystems. Especially
for migrating birds, that can face a variety of unfavorable conditions along their journey, resolving
movements of individuals across their annual cycle is necessary in order to design better targeted
conservation strategies. Here, we studied the movements of a small migratory falcon, the Lesser
Kestrel (Falco naumanni), by genetically assigning feathers from individuals of unknown origin that
concentrate in large roosts during the pre-migratory period. Our indings suggest that birds from
multiple breeding populations in the Central and Eastern Mediterranean region move towards two premigratory
sites in theBalkans, some of them detouring greatly from their expected flyways, travelling more than
500
km
to
reach
these
sites
and
prepare
for
the
post-nuptial
migration.
By
identifying
the
origin
of
individuals
using
the
pre-migratory
sites,
not
only
we
provide
a
better
understanding
of
the
possible
impact
of local
threats
at these sites on multiple breeding
populations
but
also
inform the
design
of
efective
conservation
actions
for
the
species
Genetic structure of a patchily distributed philopatric migrant: implications for management and conservation
No full textSignificant demographic fluctuations can have major genetic consequences in wild populations. The lesser kestrel
(Falco naumanni) has suffered both population declines and range fragmentation during the second half of the 20
century. In this study we analysed multilocus microsatellite data to assess the genetic structure of the species. Our
analysis revealed significant genetic structuring of lesser kestrel populations, not only at the cross-continental scale,
but also regionally within the Central and Eastern (CE) Mediterranean region. We detected signs of genetic bottlenecks
in some of the peripheral populations coupled with small effective population sizes. Values of genetic differentiation
among the largest populations were low, albeit significant, whereas the small peripheral CE Mediterranean populations
showed higher levels of differentiation from all other populations. Gene flow levels were relatively low among the
discontinuously
distributed
populations
of
the
CE
Mediterranean
region.
We
argue
that
the
observed
spatial
genetic structure can be attributed at some level to the past demographic decline
experienced by the species.
Finally,
we
identify
management
units
in
the
region,
and
inform
the
design
of
conservation
actions
aimed
at
the
increase
of population sizes and dispersal rates among peripheral populations.
t
Premigratory ecology, phylogeography and conservation genetics of the threatened raptor Falco naumanni in the Balkans
No full textNew 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.Η ανάγκη για μια πιο σφαιρική προσέγγιση στη διατήρηση των αποδημητικών ειδών έχει αρχίσει να γίνεται πρόσφατα αντιληπτή, καθώς η γενετική συνιστώσα συχνά παραβλέπεται από τις διεθνείς πολιτικές διατήρησης, ενώ είναι ελάχιστα τα παραδείγματα διαχειριστικών πρακτικών που λαμβάνουν υπόψη τα διαφορετικά στάδια ζωής των μεταναστευτικών πουλιών καθώς και στοιχεία της γενετικής των πληθυσμών τους. Μια τέτοια προσέγγιση επιχειρείται στην παρούσα διατριβή, στοχεύοντας στο μεταναστευτικό είδος πουλιού, Κιρκινέζι (Falco naumanni). Το Κιρκινέζι είναι ένα μικρό μεταναστευτικό γεράκι που αναπαράγεται στο νότιο τμήμα της Δυτικής Παλαιαρκτικής, από τη Μεσόγειο και τη Μέση Ανατολή έως την κεντρική Ασία, τις στέπες τις Μογγολίας και την Κίνα ενώ διαχειμάζει στην υποσαχάρια Αφρική. Το είδος γνώρισε μια ραγδαία μείωση του ευρωπαϊκού πληθυσμού του κατά τη δεκαετία του 1950, λόγω της εντατικοποίησης της γεωργίας, των αλλαγών στη χρήση της γης και της επακόλουθης υποβάθμισης των ενδιαιτημάτων του. Η μείωση αυτή οδήγησε στην ολική εξαφάνιση πολλών πληθυσμών αλλά και την εξαφάνιση μεμονωμένων αποικιών σε κάποιες χώρες. Σήμερα, ο συνολικός ευρωπαϊκός πληθυσμός φαίνεται μεν να έχει σταθεροποιηθεί λόγω των διαχειριστικών δράσεων που έλαβαν χώρα κατά τις προηγούμενες δεκαετίες κυρίως στην Ιβηρική χερσόνησο. Ωστόσο, στην κεντρική και ανατολική Ευρώπη, όπου το είδος εμφανίζει κατακερματισμένη κατανομή, θεωρείται πληθυσμιακά ‘εξαντλημένο’ (Depleted) και χρήζει άμεσης διατήρησης.Στην παρούσα διατριβή γίνεται χρήση γενετικών και οικολογικών δεδομένων με στόχο: α) την περιγραφή, ανάλυση και ερμηνεία των χωρικών προτύπων της γενετικής ποικιλότητας και της δομής των πληθυσμών του Κιρκινεζιού και β) την ανάδειξη της σημασίας των προμεταναστευτικών περιοχών ως σημαντικών κέντρων για τη διατήρηση του είδους. Απώτερος σκοπός είναι η παραγωγή γνώσης που θα συμβάλλει στον αποτελεσματικότερο σχεδιασμό διαχειριστικών πρακτικών και στρατηγικών διατήρησης του είδους στην περιοχή της Μεσογείου. Για να περιγραφεί η προμεταναστευτική συγκέντρωση των Κιρκινεζιών στην πόλη των Ιωαννίνων, χρησιμοποιήθηκαν δεδομένα καταμετρήσεων των ετών 2000-2015. Επίσης, εντοπίστηκαν τα δέντρα που χρησιμοποιούνται από το είδος κατά τη διάρκεια αυτής της περιόδου. Η κορύφωση της προμεταναστευτικής συγκέντρωσης των Κιρκινεζιών στην πόλη των Ιωαννίνων λαμβάνει χώρα κατά το μήνα Αύγουστο και διαρκεί 20 ημέρες. Η συγκέντρωση αυτή συμβαίνει σε ετήσια βάση ενώ ο μεγάλος αριθμός πουλιών που συγκεντρώνονται (σχεδόν 3000 άτομα) υποδεικνύει ότι δεν είναι ένα τοπικό φαινόμενο αλλά πουλιά από άλλες αναπαραγωγικές αποικίες φιλοξενούνται στην πόλη. Τα Κιρκινέζια που επισκέπτονται την περιοχή βρέθηκαν να χρησιμοποιούν αποκλειστικά τα Πλατάνια (Platanus orientalis) ως θέσεις κουρνιάσματος.Στην προσπάθεια να αποσαφηνιστούν τα πρότυπα μετανάστευσης του είδους στη Βαλκανική χερσόνησο χρησιμοποιήθηκαν παρατηρήσεις του είδους από πολίτες (citizen-science data). Επίσης με τη διερεύνηση επανευρέσεων δακτυλιωμένων πουλιών εκτιμήθηκε ο βαθμός φιλοπατρίας και τυχόν προμεταναστευτικές κινήσεις του είδους στην περιοχή. Το είδος βρέθηκε να μεταναστεύει σε ευρύ μέτωπο (broad-front) την άνοιξη, από τον Μάρτιο έως τις αρχές του Μαΐου, ενώ σε ελαφρώς στενότερο μέτωπο το φθινόπωρο από τον Αύγουστο έως τις αρχές Οκτωβρίου, αντίστροφα με τη στρατηγική μετανάστευσης των πουλιών από την Ιβηρική χερσόνησο. Τα ενήλικα Κιρκινέζια εμφάνισαν ισχυρή φιλοπάτρια συμπεριφορά, ενώ αντίθετα τα νεαρά βρέθηκαν να διασπείρονται σε μεγάλες αποστάσεις έως και πάνω από 900 χιλιόμετρα.Ένας από τους κύριους παράγοντες που διαμορφώνει τις προμεταναστευτικές συγκεντρώσεις, δηλαδή η τοπικά αυξημένη διαθεσιμότητα των τροφικών πόρων, προσεγγίστηκε με μια συγκριτική μελέτη της δίαιτας του είδους μεταξύ αναπαραγωγικής και προμεταναστευτικής περιόδου με την ανάλυση εμεσμάτων. Τα Ορθόπτερα βρέθηκαν να είναι η κύρια λεία του είδους τόσο κατά την αναπαραγωγική όσο και κατά την προμεταναστευτική περίοδο. Ωστόσο, στη διάρκεια της αναπαραγωγής το είδος επιδεικνύει μεικτή στρατηγική τροφοληψίας με ευρύ τροφικό θώκο ενώ κατά την προμετανάστευση η στρατηγική τροφοληψίας του Κιρκινεζιού φαίνεται να είναι εξειδικευμένη προς τα Ορθόπτερα και συγκεκριμένα τις ακρίδες (Acrididae). Η μελέτη της δίαιτας έδειξε εμμέσως, πως οι μη-κατακερματισμένοι ξερικοί λειμώνες περιμετρικά της πόλης των Ιωαννίνων αποτελούν ίσως το σημαντικότερο ενδιαίτημα που χρησιμοποιεί το είδος κατά την αναπαραγωγή του. Αντίθετα, κατά την προμεταναστευτική περίοδο, οι ορεινές περιοχές γύρω από την πόλη (σε απόσταση άνω των 20 χιλιομέτρων) είναι υψηλής σημασίας για το είδος καθώς διατηρούν μεγάλη αφθονία Ορθόπτερων. Προκειμένου να εκτιμηθούν τα επίπεδα γενετικής ποικιλότητας και να διερευνηθούν τα χωρικά πρότυπα γενετικής δομής του είδους, συλλέχθηκαν 295 δείγματα από 15 φυσικούς πληθυσμούς στο εύρος της κατανομής του. Οι μοριακοί δείκτες που χρησιμοποιήθηκαν ήταν 18 μικροδορυφορικοί τόποι. Τα αποτελέσματα των αναλύσεων επιβεβαιώνουν το φυλογεωγραφικό πρότυπο σύμφωνα με το οποίο οι ευρωπαϊκοί και οι ασιατικοί πληθυσμοί του είδους διαφοροποιούνται σημαντικά ενώ ο πληθυσμός του Ισραήλ εμφανίζεται γενετικά αναμεμιγμένος. Τα δεδομένα υποστηρίζουν ότι ο πληθυσμός της Λήμνου έχει συγκροτηθεί από Κιρκινέζια ασιατικής προέλευσης. Οι μεγάλου μεγέθους κεντρικοί πληθυσμοί βρέθηκαν να διατηρούν υψηλά επίπεδα γονιδιακής ροής με κάποιους από τους μικρότερους περιφερειακούς πληθυσμούς, ενώ αντίθετα, μεταξύ των περιφερειακών πληθυσμών διαπιστώνεται μειωμένη διασπορά ατόμων. Οι πληθυσμοί του είδους στη Μεσόγειο φαίνεται να έχουν επηρεαστεί διαφορετικά από την μεγάλη ιστορική μείωση καθώς τρείς από τους περιφερειακούς πληθυσμούς της κεντρικής και ανατολικής Μεσογείου βρέθηκαν να εμφανίζουν ενδείξεις διέλευσης από στενωπό ενώ οι υπόλοιποι διατηρούν υψηλά επίπεδα γονιδιακής ροής με τους κεντρικούς πληθυσμούς, αποφεύγοντας τυχόν επιπτώσεις μιας στενωπού παρόλη τη μείωση του μεγέθους τους.Για να διερευνηθεί η προέλευση των ατόμων στις προμεταναστευτικές περιοχές, απομονώθηκε γενετικό υλικό από 146 φτερά που συλλέχθηκαν από τις δύο μεγαλύτερες προμεταναστευτικές συγκεντρώσεις του είδους στα Βαλκάνια: την πόλη των Ιωαννίνων και την κοιλάδα του Δρίνου στη νότια Αλβανία. Πραγματοποιήθηκαν δοκιμασίες κατάταξης των σύνθετων γονότυπων των φτερών σε εννιά αναπαραγωγικούς πληθυσμούς αναφοράς. Τα Κιρκινέζια που επισκέπτονται την πόλη των Ιωαννίνων κατά την προμετανάστευση προέρχονται από τουλάχιστον έξι διαφορετικούς αναπαραγωγικούς πληθυσμούς του είδους για τους οποίους υπήρχαν διαθέσιμα γενετικά δεδομένα (γονότυποι). Περαιτέρω ανάλυση μοντελοποίησης των αλληλικών συχνοτήτων έδειξε ότι άτομα πιθανόν να προέρχονται και από πέντε επιπλέον πληθυσμούς. Φαίνεται πως οι προμεταναστευτικές συγκεντρώσεις διαδραματίζουν σημαντικό ρόλο στη διαμόρφωση της γενετικής δομής των πληθυσμών, καθώς προσελκύουν στις αντίστοιχες περιοχές άτομα για μελλοντική αναπαραγωγή.Εν κατακλείδι, τα αποτελέσματα και συμπεράσματα της παρούσας μελέτης μπορούν να αξιοποιηθούν για το σχεδιασμό μιας αποτελεσματικής στρατηγικής διατήρησης του είδους στην περιοχή της Μεσογείου. Μια τέτοια σφαιρική προσέγγιση αφενός επιτρέπει την υλοποίηση στοχευμένων διαχειριστικών πρακτικών, αφετέρου αποτελεί μια οικονομικά αποδοτική στρατηγική για την ανάκαμψη των πληθυσμών του είδους
Egyptian Vulture LIFE project evaluation - data and model code
No full text<p>This work was carried out in the framework of the LIFE projects “The Return of the Neophron” (LIFE10 NAT/BG/000152) and “Egyptian Vulture New LIFE” (LIFE16 NAT/BG/000874, www.LifeNeophron.eu) funded by the European Union and co-funded by the A. G. Leventis Foundation, MAVA Foundation, and the BirdLife GEF/UNDP Migratory Soaring Birds project. The data and model code allow an evaluation of the changes in the Egyptian Vulture breeding population on the Balkans before and since LIFE-funded conservation management activities.</p>revised code after revision of manuscript - code now includes GOF test and PV
Egyptian Vulture LIFE project evaluation - data and model code
No full text<p>This work was carried out in the framework of the LIFE projects “The Return of the Neophron” (LIFE10 NAT/BG/000152) and “Egyptian Vulture New LIFE” (LIFE16 NAT/BG/000874, www.LifeNeophron.eu) funded by the European Union and co-funded by the A. G. Leventis Foundation, MAVA Foundation, and the BirdLife GEF/UNDP Migratory Soaring Birds project. The data and model code allow an evaluation of the changes in the Egyptian Vulture breeding population on the Balkans before and since LIFE-funded conservation management activities.</p>
Stopover Ecology of the European Turtle Dove (Streptopelia turtur), a Threatened Migratory Bird Species, after the Crossing of an Extended Ecological Barrier
No full textMigratory routes, important stopover sites and wintering grounds for the Turtle Dove, a declining trans-Saharan migratory bird, are known mainly for populations in western and central Europe, but very little is known about birds using the eastern migration flyway. By combining long-term ringing data, tracking data and citizen science data, a comprehensive picture of the stopover ecology of the Turtle Dove’s spring migration in the eastern Mediterranean is presented. Furthermore, a quantitative estimate of the number of birds that migrate over Greece during the spring migration is given. Approximately 16% of the European population migrates through Greece, passing through as early as the end of March, with the passage lasting up to the end of May. On average, the species arrives depleted after the crossing of the Sahara Desert and the Mediterranean Sea, with no systematic refuelling event taking place in North Africa. Both tracking and ringing data indicate that the birds undergo an extensive stopover after the barrier crossing (as much as close to three weeks). Turtle Doves additionally show significant body mass gain during their stay, indicating the potential importance of stopover sites after the Mediterranean Sea for the conservation of the species
Genetic insight into a polygenic trait using a novel genome-wide association approach in a wild amphibian population
No full textBody size variation is central in the evolution of life-history traits in amphibians, but the underlying genetic architecture of this complex trait is still largely unknown. Herein, we studied the genetic basis of body size and fecundity of the alternative morphotypes in a wild population of the Greek smooth newt (Lissotriton graecus). By combining a genome-wide association approach with linkage disequilibrium network analysis, we were able to identify clusters of highly correlated loci thus maximizing sequence data for downstream analysis. The putatively associated variants explained 12.8% to 44.5% of the total phenotypic variation in body size and were mapped to genes with functional roles in the regulation of gene expression and cell cycle processes. Our study is the first to provide insights into the genetic basis of complex traits in newts and provides a useful tool to identify loci potentially involved in fitness-related traits in small data sets from natural populations in non-model species.Peer reviewe
Genetic insight into a polygenic trait using a novel Genome Wide Association approach in a wild amphibian population
No full text<p>Body size variation is central in the evolution of life history traits in amphibians, but the underlying genetic architecture of this complex trait is still largely unknown. Herein, we studied the genetic basis of body size and fecundity of the alternative morphotypes in a wild population of the Greek smooth newt (<em>Lissotriton graecus</em>). By combining a Genome-wide association approach with linkage disequilibrium network analysis, we were able to identify clusters of highly correlated loci thus maximizing sequence data for downstream analysis. The putatively associated variants explained 12.8% to 44.5% of the total phenotypic variation in body size and were mapped to genes with functional roles in the regulation of gene expression and cell cycle processes. Our study is the first to provide insights into the genetic basis of complex traits in newts and provides a useful tool to identify loci potentially involved in fitness related traits in small data sets from natural populations in non-model species.</p><p>Funding provided by: State Scholarships Foundation<br>Crossref Funder Registry ID: https://ror.org/023z3dm33<br>Award Number: MIS-5000432</p><p>Phenotypic measurments were collected from female Greek smooth newts, including snout to vent length, body weight and reproductive components.</p>
<p>Genomic DNA was extracted from tissue samples. ddRAD libraries were produced using an IGATech custom protocol (IGA Technology Services, Udine, Italy), with minor modifications with respect to Peterson's double digest restriction-site associated DNA preparation (Peterson et al., 2012), using SphI (5'GCATG 3') and BamHI (5'GGATCC 3') endonucleases. Library pools were selected on a BluePippin (Sage Science Inc. Beverly, MA, USA) setting the range to 380–500 bp. The resulting libraries were checked with both a Qubit 2.0 Fluorometer (Invitrogen, Carlsbad, CA) and by Bioanalyzer DNA Assay (Agilent Technologies, Santa Clara, CA). Libraries were sequenced with 150 cycles in paired end mode on a NovaSeq 6000 Sequencing System following the manufacturer's instructions (Illumina, San Diego, CA).</p>
<p>Raw reads were demultiplexed and trimmed to remove adaptors using the process_radtags utility included in Stacks v.2.0 (Catchen et al., 2013). Short reads were de novo assembled, catalogued and matched using the ustacks cstacks, sstacks and tsv2bam (for paired-end reads) utilities in Stacks. SNPs were called using gstacks which assembles and genotypes contigs. SNP filtering was done under the populations component included in Stacks.</p>
<p>Here we provide the vcf files used in the study along with the imputed genotyping file and the genetic relationship matrix (GRM) that were generated. We also provide files containing individual phenotypic measurments used for the association analysis in Tassel and LDna. </p>
Diet composition of White-tailed Eagles inhabiting two adjacent inland lakes in Northern Greece
No full textIn territorial raptors, breeding performance and foraging behaviour are affected by territory characteristics as the abundance and availability of different prey species varies between habitats. In this study, we examined the diet of two White-tailed Eagle pairs, occupying neighbouring territories in two adjacent inland lakes in Northern Greece. We assess the diet composition of the species in the southernmost part of its European range and evaluate any intraspecific differences in the diet that may reflect resource and/or niche partitioning between territories. We found that birds and specifically waterbirds comprise the largest and quantitatively most important part of the White-tailed Eagle´s diet, with fish being the second most important prey group that was only found in the nest remains from one territory. There was high diet overlap between the two territories and when considering only avian prey our results suggest that the species predates on heavier (and the most common) waterbird species. A main factor that could be driving differences in the abundance and availability of different prey species between territories could be lake physiography, as our results point to a segregation and a subsequent resource partitioning between territories, with each pair utilizing an adjacent lake and its associated habitats. Competition and territoriality therefore seem to be important intraspecific interactions that along with prey availability could promote changes in territory size and ultimately affect individual fitness
The state of breeding birds in Greece: trends, threats, and implications for conservation
No full textBirds are suffering from steep population declines on a global scale and they are one of the few taxonomic groups for which these declines are well documented by long-term monitoring data. This study provides a synthesis of the status of the breeding birds of Greece. To this aim, we retrieved population size estimates from six sources spanning 22 years (1992-2014) and calculated species’ trends in Greece. Using the IUCN Red List assessments for each species we assessed whether ecological traits including habitat and diet preferences were associated with species’ trends and conservation status in Europe and determined major threats affecting birds in Greece. Moreover, we assessed the importance of Important Bird & Biodiversity Areas (IBAs) in terms of declining trigger species. Results showed that almost one fifth of the breeding birds in Greece have declining populations. Raptors were found to be the most threatened group of birds whereas the highest declines by dietary group were observed in scavengers, with 60% of species showing a decreasing trend. The most common threats were those that cause habitat alteration and degradation as well as more direct effects such as poisoning. Our results suggest that restoration of habitat and ecosystem functions along with the management of protected areas and improvement of legislation should be the main conservation actions undertaken and pinpointed the IBAs where they should be prioritized for implementation. Finally, further research, especially on specific drivers of population change, along with further examination of current and past population trends, will increase the power and accuracy of future regional Red List assessments especially concerning the breeding species for which the country bears the greatest responsibility
