15 research outputs found
Host dispersal shapes the population structure of a tick-borne bacterial pathogen
Birds are hosts for several zoonotic pathogens. Because of their high mobility, especially of longdistance migrants, birds can disperse these pathogens, affecting their distribution and phylogeography. We focused on Borrelia burgdorferi sensu lato, which includes the causative agents of Lyme borreliosis, as an example for tick-borne pathogens, to address the role of birds as propagation hosts of zoonotic agents at a large geographical scale. We collected ticks from passerine birds in 11 European countries. B. burgdorferi s.l. prevalence in Ixodes spp. was 37% and increased with latitude. The fieldfare Turdus pilaris and the blackbird T. merula carried ticks with the highest Borrelia prevalence (92 and 58%, respectively), whereas robin Erithacus rubecula ticks were the least infected (3.8%). Borrelia garinii was the most prevalent genospecies (61%), followed by B. valaisiana (24%), B. afzelii (9%), B. turdi (5%) and B. lusitaniae (0.5%). A novel Borrelia genospecies "Candidatus Borrelia aligera" was also detected. Multilocus sequence typing (MLST) analysis of B. garinii isolates together with the global collection of B. garinii genotypes obtained from the Borrelia MLST public database revealed that: (a) there was little overlap among genotypes from different continents, (b) there was no geographical structuring within Europe, and (c) there was no evident association pattern detectable among B. garinii genotypes from ticks feeding on birds, questing ticks or human isolates. These findings strengthen the hypothesis that the population structure and evolutionary biology of tick-borne pathogens are shaped by their host associations and the movement patterns of these hosts.Peer reviewe
Diet of the Barn Owl (Tyto alba) and Little Owl (Athene noctua) in wetlands of northeastern Greece
ABSTRACT. The diets of the Barn Owl ( Tyto alba ) and Little Owl ( Athene noctua ) were studied through pellet analysis in four northeastern Greek wetlands. Results from the months February-September showed that in all areas, the most important prey for the Barn Owl were small mammals (mainly Mus spp., Microtus rossiaemeridionalis , Crocidura spp. and Apodemus spp.) The mammalian prey composition showed winter-summer and among-areas differences. Except in the Evros Delta, where small mammals were dominant by both numbers and biomass, the most numerous prey of the Little Owl were insects (mainly Orthoptera and Coleoptera), but small mammals (mainly M. rossiaemeridionalis and Mus spp.) dominated the diet by biomass. Significant seasonal differences in prey composition occurred in the Evros Delta, while the summer diets were also different among wetlands. Barn Owl median prey biomass (MPB) was significantly higher than Little Owl MPB in summer, whereas prey diversity and evenness values were higher in the latter species as a consequence of considerable amounts of insects in its diet. In both owl species, MPB differed significantly among the wetlands in the year of study, while seasonal differences occurred occasionally in some of the wetlands. The total prey overlap (Pianka's symmetric equation) of the two owl species in the summer (range 27%-53%) was lower than the mammalian prey overlap (60%-97%) and both were greater than those found by other authors in most parts of the Mediterranean
Winter Diet of the Barn Owl (tyto Alba) and Long-eared Owl (asio Otus) in Northeastern Greece: A Comparison
Winter diet of the Marsh Harrier Circus aeruginosus (Aves, Accipitriformes) in the Evros Delta (Greece)
The diet of the Marsh Harrier (Circus aeruginosus) was studied with the analysis of pellets collected in the Evros Delta. In total, 141 prey items were identified in 86 pellets. In terms of numbers, the diet consisted of 66.7% mammals, 27.7% birds and 5.7% insects. Considering biomass, birds were the most important prey, while mammals made up 36.6% of the diet. The most important species, in terms of biomass, were Sibling Vole (Microtus levis) -31.1%-,Teal (Anas crecca) -17.7%-, Moorhen (Gallinula chloropus) and Black-headed Gull (Chroicocephalus ridibundus) -11.8% each-. The mean estimated prey weight was 36 g., ranging from 1 to 300 g
Diet composition of White-tailed Eagles inhabiting two adjacent inland lakes in Northern Greece
In 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
Pronounced Seasonal Diet Diversity Expansion of Golden Eagles (<i>Aquila chrysaetos</i>) in Northern Greece during the Non-Breeding Season: The Role of Tortoises
Golden Eagles are resident in Greece and known to feed mainly on tortoises when breeding. However, information on alternative prey is scarce, especially during the tortoise brumation, that roughly coincides with the eagles’ non-breeding season. We analyzed 827 prey items collected from 12 territories over five territory years and 84 records of eagles hunting or feeding behavior. Tortoises dominated the breeding season diet (71% of prey categories on average) and over half of all hunting/feeding observations. While no spatial structure was evident, habitat variables such as forest canopy cover were important associates in golden eagle diet seasonally. A significant seasonal pattern emerged in diet diversity, using a subset of six territories with at least 10 samples per season. Eagles shifted from a narrow, reptile- based breeding season diet dominated by tortoises to a broader non-breeding season diet, that included more carrion, mammals and birds. Breeding season specialization on ectothermic prey is a trait usually associated with migratory raptors in the Western Palearctic. The observed dietary diversity expansion accompanied by residency in the absence of ectothermic prey, highlights the adaptability of the golden eagle, a generalist predator. Tortoise populations in Greece are of conservation concern and land use changes as well as climate change, such as development and land abandonment may increase the prevalence of catastrophic megafires, exacerbating the threats to the golden eagle’s main prey when breeding. We discuss this and other diet related conservation implications for the species in northern Greece
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
Report of the long-term efficacy of two cycles of adjuvant bleomycin/etoposide/cisplatin in patients with stage I testicular nonseminomatous germ-cell tumors (NSGCT): a risk adapted protocol of the Hellenic Cooperative Oncology Group
Objectives: Stage I testicular nonseminomatous germ-cell tumors (NSGCT) are highly curable. Following orchidectomy surveillance, adjuvant chemotherapy and retroperitoneal lymph node dissection can be applied. Certain factors are used to select patients in high-risk for relapse. We report the outcome and safety of a risk-adapted strategy by the Hellenic Cooperative Oncology Group. Methods: Between 1994 and 2004, 142 patients with stage I NSGCT and 1 of the following risk factors: lymphovascular invasion (LVI), invasion of tunica vaginalis, spermatic cord, rete testis or scrotal wall, embryonal component &gt;50% of the total tumor, were prospectively included in a protocol of adjuvant chemotherapy consisting of two 3-week courses of bleomycin 15 IU, etoposide 120 mg/m2, and cisplatin 40 mg/m2 for 3 consecutive days with G-CSF support. Results: Median follow-up was 79 months and 138 patients have been followed for at least 2 years. Seventy-seven patients (54%) had LVI and 74 (52%) had &gt;50% embryonal component. There was 1 relapse, which was cured with chemotherapy and surgery. Another patient died due to disease-unrelated causes and 1 patient developed a new primary of the remaining testicle, which was cured with surgery. Conclusion: Two cycles of bleomycin/etoposide/cisplatin is an effective and safe form of adjuvant therapy in high-risk stage I NSGCT. © 2011 Elsevier Inc