Landscape and Climatic Variations Shaped Secondary Contacts amid Barn Owls of the Western Palearctic

The combined actions of climatic variations and landscape barriers shape the history of natural populations. When organisms follow their shifting niches, obstacles in the landscape can lead to the splitting of populations, on which evolution will then act independently. When two such populations are reunited, secondary contact occurs in a broad range of admixture patterns, from narrow hybrid zones to the complete dissolution of lineages. A previous study suggested that barn owls colonized the Western Palearctic after the last glaciation in a ring-like fashion around the Mediterranean Sea, and conjectured an admixture zone in the Balkans. Here, we take advantage of whole-genome sequences of 94 individuals across the Western Palearctic to reveal the complex history of the species in the region using observational and modeling approaches. Even though our results confirm that two distinct lineages colonized the region, one in Europe and one in the Levant, they suggest that it predates the last glaciation and identify a secondary contact zone between the two in Anatolia. We also show that barn owls recolonized Europe after the glaciation from two distinct glacial refugia: a previously identified western one in Iberia and a new eastern one in Italy. Both glacial lineages now communicate via eastern Europe, in a wide and permeable contact zone. This complex history of populations enlightens the taxonomy of Tyto alba in the region, highlights the key role played by mountain ranges and large water bodies as barriers and illustrates the power of population genomics in uncovering intricate demographic patterns

An annotated chromosome-scale reference genome for Eastern black-eared wheatear (Oenanthe melanoleuca).

Pervasive convergent evolution and in part high incidences of hybridization distinguish wheatears (songbirds of the genus Oenanthe) as a versatile system to address questions at the forefront of research on the molecular bases of phenotypic and species diversification. To prepare the genomic resources for this venture, we here generated and annotated a chromosome-scale assembly of the Eastern black-eared wheatear (O. melanoleuca). This species is part of the O. hispanica-complex that is characterized by convergent evolution of plumage coloration and high rates of hybridization. The long-read-based male nuclear genome assembly comprises 1.04 Gb in 32 autosomes, the Z chromosome, and the mitogenome. The assembly is highly contiguous (contig N50: 12.6 Mb; scaffold N50: 70 Mb), with 96% of the genome assembled at chromosome level and 95.5% BUSCO completeness. The nuclear genome was annotated with 18,143 protein-coding genes and 31,333 mRNAs (annotation BUSCO completeness: 98.0%), and about 10% of the genome consists of repetitive DNA. The annotated chromosome-scale reference genome of Eastern black-eared wheatear provides a crucial resource for research into the genomics of adaptation and speciation in an intriguing group of passerines

The trophic ecology of barn owl in the agricultural ecosystems of Central Greece: its application in the distribution and abundance of its prey

Esta Tesis Doctoral tuvo cuatro objetivos principales. Estudiar la ecología trófica de la Lechuza común en los agro-ecosistemas de Grecia central, comparar los resultados con otras dietas Europeas y Griegas, y desde el espectro de la dieta buscar patrones de distribución, abundancia y estructura de las poblaciones de los micromamíferos en la región de Tesalia, y estudiar su uso espacial estacional en respecto al cambio estacional del hábitat agrícola. 31 sitios de nidificación naturales fueron localizados en la llanura de Tesalia. Un total de 124 muestras han sido realizadas y 10.065 egagrópilas fueron coleccionadas, reflejando 2 épocas reproductoras y 2 no reproductoras. Después el análisis de las egagrópilas un total de 29.061 presas fueron identificadas, en su mayoría micromamíferos. 28 variables ambientales fueron cuantificadas que fueron incluidas en el ratio de 2 km alrededor de cada sitio de muestra. El análisis de datos ecológicos multivariante ha sido aplicada utilizando el programa CANOCO y con el uso de Modelos Lineales Generalizables, y el Análisis de Gradientes Directa ha sido aplicado utilizando el Análisis de Redundancias. La Lechuza común en Tesalia ha capturado principalmente topillos, y especialmente durante la época reproductora, demostrando también una selección de hábitat fuerte hacia pequeñas parcelas de tierra que sostenían topillos. Alternativamente durante las épocas no reproductoras ha capturado ratones y ratas forrajeando a otros tipos de hábitat. La depredación sobre las ratas durante la época no reproductora ha sido una de las más altas en Europa Mediterránea. Nuevos datos de distribución se han presentado por todas las 15 especies de micromamíferos, que anteriormente se consideraban como ausentes de la llanura de Tesalia. Crocidura suaveolens y Microtus thomasi han sido correlacionadas con tipos del suelo y textura del suelo, y han sido fuertemente afectadas del cambio estacional del hábitat agrícola. Las especies del genero Mus y Apodemus siendo competidores débiles y más generalistas han diferenciado sus nichos, ocupando tipos de hábitat otros de aquellas especies especializadas y territoriales. Microtus guentheri ha sido la especie más abundante en el primer año del estudio pero su población sufrió un decrecimiento fuerte durante los tres años del estudio, mientras tanto los demás grupos de micromamíferos han aumentado.The PhD Thesis had four main objectives. Study Barn owl s trophic ecology in the agroecosystems of central Greece, compare it with Greek and European diets, and through that diet spectrum search for patterns of distribution, abundance and structure of small mammal populations in the region of Thessaly, and study their seasonal space use in relation to the change of agricultural habitat. A total of 31 Barn owl breeding sites were located in the lowlands of Thessaly. A total of 124 samplings were realized and 10.065 pellets were collected, reflecting concretely two breeding and two non-breeding periods. After pellet analysis a total of 29.061 prey items were indentified, mainly comprised of small mammals. 28 environmental variables were quantified, as they were included in a 2 km ratio around each sampling site. Multivariate analysis of ecological data was applied with the software CANOCO and the use of Generalized Linear Models, and Direct Gradient Analysis was applied using Redundancy Analysis. Barn owl in Thessaly preyed heavily on voles, especially during breeding seasons and it also presented a strong habitat selection towards small habitat patches that sustained voles. Alternatively during non breeding seasons it preyed on mice and rats foraging over different habitat types. Rat predation during non breeding season was among the highest in Mediterranean Europe. New distribution data were presented for a total of 15 small mammal species, previously considered absent from Thessaly plains. Crocidura suaveolens and Microtus thomasi were correlated with soil types and soil texture, and were strongly affected from the seasonal change of agricultural habitat. Mus and Apodemus species as weak competitors and generalists differentiated their niches by occupying habitat types others than those of specialized and territorial species. Microtus guentheri was the most abundant in the first year but its population crashed during the three year study, while populations of all other small mammal groups increased

Distribution of Four Vole Species through the Barn Owl <i>Tyto alba</i> Diet Spectrum: Pattern Responses to Environmental Gradients in Intensive Agroecosystems of Central Greece

Voles are the most common vertebrate pests in European agriculture. Identifying their distribution and abundance patterns provides valuable information for future management. Barn Owl diet analysis is one of the optimum methods used to record small mammal distribution patterns on large spatial scales. From 2003 to 2005, a total of 10,065 Barn Owl pellets were collected and analyzed from 31 breeding sites in the largest agroecosystem in Greece, the Thessaly plains. A total of 29,061 prey items were identified, offering deep insight into small mammal distribution, specifically voles. Four discrete vole species (Harting’s vole Microtus hartingi, East European vole Microtus levis, Thomas’s pine vole Microtus thomasi, and Grey dwarf hamster Cricetulus migratorius) comprised 40.5% (11,770 vole prey items) of the total Barn Owl prey intake. The presence and abundance of the voles varied according to underlying environmental gradients, with soil texture and type playing a major role. M. levis showed no significant attachments to gradients, other than a mild increase in Mollisol soils. It was syntopic in all sites with M. hartingi, which was the dominant and most abundant small mammal species, preferring non-arable cultivated land, natural grasslands, set-aside fields, and fallow land. M. thomasi was strictly present in western Thessaly and strongly associated with a sandy-clay soil texture and Alfisol soils. C. migratorius was the least represented vole (162 items), exclusively present in eastern Thessaly and demonstrating a stronger association with cereals, Mollisol soils, and an argillaceous-clay soil texture. This is the first study in Greece at such a large spatial scale, offering insights for pest rodents’ distribution in intensive agroecosystems and their response to environmental gradients including soil parameters

Temporal shifts in floristic and avian diversity in Mediterranean pine forest ecosystems under different fire pressure: The island of Zakynthos as a case study

We evaluated how fire impacts the ecological coherence of Aleppo pine forests and their biodiversity over a 40-year period. The study area forms part of an insular ecosystem of Zakynthos Island (Zante) in western Greece, which forms part of the Ionian Islands. Post-fire effects were studied for both plant and bird diversity at 20 sampling plots, using stratified random sampling, during the summer of 2012. The plots were selected based on the frequency of burning since the 1970s. Sites were categorized as: 1) no burning for &gt;40 years, 2) burnt once in the 1970s, 3) burnt twice, first in the 1970s and again in 2000–2010, 4) burnt three times, first in the 1970s, and twice more in 2000–2010, and 5) burnt four times, first in the1970s, twice more in 2000–2010, and again in 2011. A total of 79 plant species and 26 bird species were recorded at the studied sites. One-way ANOVA analysis showed that fire intensity has a significant impact on alpha floristic diversity. Average plant species richness at sites that burned in 2011 was significantly higher than in those that burned in the 1970s. Detected differences in bird species richness were not significant; however, more species were documented in the forested habitats (unburnt for &gt;40 years, and burnt in the 1970s). The highest Jaccard similarity index was observed between the sites that had not burned for more than 40 years and the sites that burned in the 1970s. The lowest floristic similarity to non-burnt sites was observed between the recently burnt sites in 2011 and the sites that burned in the 1970s. The lowest bird similarity was detected between recently burnt sites in 2011 and sites that had not burned for more than 40 years. DCA ordination showed the presence of a clear fire gradient, from intensively burnt open sites to non-burnt forest sites. We suggest that fire is essential to maintain biodiversity in Aleppo pine forests, but only at intermediate frequency

Diet Composition and Feeding Strategies of the Stone Marten (Martes foina) in a Typical Mediterranean Ecosystem

Stone martens (Martes foina) are documented as generalist throughout their distributional range whose diet composition is affected by food availability. We tested if this occurs and what feeding strategies it follows in a typical Mediterranean ecosystem in Central Greece by analysing contents from 106 stomachs, seasonally collected from three different habitats during 2003–2006. Seasonal variation in diet and feeding strategies was evident and linked to seasonal nutritional requirements, but possibly imposed by strong interference competition and intraguild predation. Fleshy fruits and arthropods predominated in the diet, but also mammals and birds were frequently consumed. An overall low dietary niche breadth (BA=0.128) indicated a fruit specialization tendency. A generalised diet occurred in spring with high individual specialisation, whereas more animal-type prey was consumed than fruits. A population specialization towards fruits was indicated during summer and autumn, whereas insects were consumed occasionally by males. In those seasons it switched to more clumped food types such as fruits and insects. In winter it selectively exploited both adult and larvae insects and partially fruits overwinter on plants. The tendency to consume particular prey items seasonally reflected both the population specialist behaviour and the individual flexibility preyed on different food resources

Figure 3 in Home range and foraging habitat selection by breeding lesser kestrels (Falco naumanni) in Greece

Figure 3. Percentage of foraging locations over used habitats (open columns) of radio-tagged male and female lesser kestrels in relation to habitat available (black columns) within home ranges, during breeding stages in central Greece, 2008.Published as part of Vlachos, Christos G., Bakaloudis, Dimitrios E., Kitikidou, Kyriaki, Goutner, Vassilis, Bontzorlos, Vasileios, Papakosta, Malamati A. & Chatzinikos, Evangelos, 2014, Home range and foraging habitat selection by breeding lesser kestrels (Falco naumanni) in Greece, pp. 371-381 in Journal of Natural History 49 (5) on page 376, DOI: 10.1080/00222933.2013.825022, http://zenodo.org/record/400409

Figure 1 in Home range and foraging habitat selection by breeding lesser kestrels (Falco naumanni) in Greece

Figure 1. Minimum convex polygon home ranges (outer: 100%, interior: 95% of locations) of male (A) and female (B) lesser kestrels during the breeding season in central Greece, 2008.Published as part of Vlachos, Christos G., Bakaloudis, Dimitrios E., Kitikidou, Kyriaki, Goutner, Vassilis, Bontzorlos, Vasileios, Papakosta, Malamati A. & Chatzinikos, Evangelos, 2014, Home range and foraging habitat selection by breeding lesser kestrels (Falco naumanni) in Greece, pp. 371-381 in Journal of Natural History 49 (5) on page 375, DOI: 10.1080/00222933.2013.825022, http://zenodo.org/record/400409

Bioclimatic and environmental suitability models for capercaillie (Tetrao urogallus) conservation: Identification of optimal and marginal areas in Rodopi Mountain-Range National Park (Northern Greece)

Capercaillie is a species of particular conservation importance for Europe due to the observed population decline in various parts of its distribution. In the current study, the environmental and habitat requirements of the species are investigated at the southernmost range of its European distribution (Rodopi Mountain-Range National Park, northern Greece) using a set of 95 observations of species presence and a maximum-entropy (MaxEnt) modeling approach. A bioclimatic dataset derived from the Bioclim open source database and a set of environmental variables, mainly forest land-cover types and topographical variables, were employed to explain the current distribution of the species and to delineate potentially suitable areas for its distribution. The best scale per environmental variable was chosen among three different spatial scales (10 ha, 100 ha and 500 ha), in order to build a multiscale environmental model. According to our results, the species demonstrated a very narrow niche which is determined primarily by bioclimatic factors while a number of habitat requirements within a strict bioclimatic zone where also identified. It requires wet areas with mean summer temperature not exceeding 10 °C, which are only found at the higher altitudes of the National Park. Α strong tendency was also found for capercaillies to inhabit forest stands of norway spruce (Picea abies) with a minimum cover of 10% at an intermediate scale of 100 ha, followed at a larger scale i.e. 500 ha by pure beech (Fagus spp.) forests or mixed with pines (Pinus spp.), where optimum tree density ranges from 50% to 80%. Bioclimatic and environmental presence-prediction maps were reclassified in four suitability classes (unsuitable, marginal, sub-optimal, optimal), based on three Maxent thresholds (Minimum Training Presence, Fixed Cumulative Value 5 and Value 10). Monitoring the marginal climatic zone for the species and ensuring suitable habitats within it is the key for the species conservation in its southernmost part of its distribution. Keywords: Capercaillie, Rodopi Mountain-Range National Park, Habitat suitability, Optimal niche, MaxEn

A greener path for the EU common agricultural policy

A greener path for the EU common agricultural polic