Phenology of the avian spring migratory passage in Europe and North America : Asymmetric advancement in time and increase in duration

Climate change has been shown to shift the seasonal timing (i.e. phenology) and distribution of species. The phenological effects of climate change on living organisms have often been tested using first occurrence dates, which may be uninformative and biased. More rarely investigated is how different phases of a phenological sequence (e.g. beginning, central tendency and end) or its duration have changed over time. This type of analysis requires continuous observation throughout the phenological event over multiple years, and such data sets are rare. In this study we examined the impact of temperature on long-term change of passage timing and duration of the spring migration period in birds, and which species' traits explain species-specific variation. Data used covered 195 species from 21 European and Canadian bird observatories from which systematic daily sampling protocols were available. Migration dates were negatively associated with early spring temperature and timings had in general advanced in 57 years. Short-distance migrants advanced the beginning of their migration more than long-distance migrants when corrected for phylogenic relatedness, but such a difference was not found in other phases of migration. The advancement of migration has generally been greater for the beginning and median phases of migration relative to the end, leading to extended spring migration seasons. Duration of the migration season increased with increasing temperature. Phenological changes have also been less noticeable in Canada even when corrected for rate of change in temperature. To visualize long-term changes in phenology, we constructed the first multi-species spring migration phenology indicator to describe general changes in median migration dates in the northern hemisphere. The indicator showed an average advancement of one week during five decades across the continents (period 1959-2015). The indicator is easy to update with new data and we therefore encourage future research to investigate whether the trend towards longer periods of occurrence or emergence in spring is also evident in other migratory populations. Such phenological changes may influence detectability in monitoring schemes, and may have broader implications on population and community dynamics.Peer reviewe

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

Koon vaikutus sinitiaisen (Parus caeruleus) selviytymiseen talvesta

Sinitiaisen levinneisyysalue on laajentunut nopeasti pohjoista kohti muutamassa vuosikymmenessä. Lajin talvikanta on samanaikaisesti runsastunut Suomessa moninkertaiseksi. Pohjoisessa ravinnon saatavuus talven aikana on yksi selviytymiseen vaikuttavista päätekijöistä. Kilpailu niukoista resursseista on olennainen tekijä talviolosuhteissa eläville linnuille. Lyhyiden ja kylmien talvipäivien aikana sekä ankarimpien ajanjaksojen aikana parhaiten energiantarpeen täyttämään pystyvillä yksilöillä on suurimmat selviytymismahdollisuudet. Linnun koko on ominaisuus, jonka oletetaan seuraavan ympäristötekijöistä johtuvasta valinnasta. Luonnonvalinta suosii yksilöitä, joiden ominaisuudet auttavat yksilöä selviytymään vallitsevissa olosuhteissa. Dominoivammassa asemassa olevat yksilöt yleensä saavat enemmän ravintoa ja pystyvät olemaan suojaisemmissa paikoissa parven sisäisesti. Ruokintapaikoilla isokokoiset koirassinitiaiset ovat usein dominoivampia kuin naaraat ja pienempikokoiset koiraat. Suuremmasta ruumiinkoosta on hyötyä myös kylmästä talviyöstä selviämiseen, koska energiankulutus on suhteellisesti pienempi kuin pienillä yksilöillä. Tämä edellyttää kuitenkin, että ravinnon absoluuttinen määrä ei ole rajoittavana tekijänä. Bergmannin säännön mukaan lämpimämmillä alueilla tasalämpöisen lajin yksilöt ovat pienempiä kuin kylmillä alueilla elävät. Tämän tutkimuksen tarkoituksena on selvittää, vaikuttaako linnun koko nuorten sinitiaisten selviytymiseen talvesta, ja millä tavalla talven ankaruus vaikuttaa erikokoisten sinitiaisyksilöiden selviytymiseen niiden ensimmäisestä elintalvesta, sekä vaikuttaako talven ankaruus sukupuolten elossasäilyvyyteen samalla tavalla. Tutkimusaineisto on kerätty Turun Ruissalossa talvina 1975/76-1985/86 ja 1999/2000-2013/14. Sinitiaiskoiraiden elossasäilyvyys oli pienempi kylmien talvien jälkeen. Koirailla suuremmat yksilöt selvisivät kylmistä talvista suuntaa antavasti pienikokoisia yksilöitä paremmin, mutta naarailla ero elossasäilyvyydessä erikokoisten yksilöiden välillä oli vähäisempi. Tulos viittaisi siihen, että sinitiaisella suuremmasta koosta on hyötyä varsinkin koiraille kylmimmistä talvista selviytymisen kannalta

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.This study received financial support from Fundação para a Ciência e a Tecnologia by the strategic program of MARE (MARE ‐ UID/MAR/04292/2013) and the fellowship to Ana Cláudia Norte (SFRH/BPD/108197/2015), and the Portuguese National Institute of Health. Raivo Mänd, Tomi Trilar, Tapio Eeva, Tomas Grim and Dieter Heylen were supported by the Estonian Research Council (research grant # IUT34‐8), the Slovenian Research Agency ‐programme “Communities, relations and communications in the ecosystems” (No. P1‐0255), the Academy of Finland (project 265859), the Internal Grant Agency of Palacky University (PrF_2014_018, PrF_2015_018, PrF_2013_018) and the Marie Sklodowska‐Curie Actions (EU‐Horizon 2020, Individual Global Fellowship, project no 799609), respectively

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

Host dispersal shapes the population structure of a tick‐borne bacterial pathogen

Abstract 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