Search results for "birds"
showing 10 items of 291 documents
Effects of habitat restoration on peatland bird communities
2020
Restoration of damaged ecosystems has become an important tool to slow down the biodiversity loss and to maintain ecosystem services. Peatland bird populations have shown a substantial decline during the recent decades in Northern Europe as a consequence of peatland drainage. We studied whether restoration of peatlands drained for forestry affects bird communities. We conducted bird surveys at 11 peatlands in Western Finland, where each of the restored and their pristine counterparts were surveyed before restoration and yearly after restoration during 2010–2018. We used linear mixed effect models to analyze whether restoration affected the number of species and territories of peatland speci…
Range size: Disentangling Current Traits and Phylogenetic and Biogeographic Factors
2006
The range size of a species can be determined by its current traits and by phylogenetic and biogeographic factors. However, only rarely have these factors been studied in combination. We use data on the geographic range sizes of all 26 Sylvia warblers to explicitly test whether range size was determined by current species-specific traits (e.g., body size, dispersal ability), phylogenetic factors (e.g., age of the lineage), or environmental, biogeographic factors (e.g., latitudinal position of the range). The results demonstrated that current traits and phylogenetic and biogeographic factors were interrelated. While a number of factors were significant in simple regression analyses, only one…
Immunity, resistance and tolerance in bird-parasite interactions.
2013
12 pages; International audience; Interacting pathogens and hosts have evolved reciprocal adaptations whose function is to allow host exploitation (from the pathogen stand point) or minimize the cost of infection (from the host stand point). Once infected, two strategies are offered to the host: parasite clearing (resistance) or withstanding the infection while paying a low fitness cost (tolerance). In both cases, the immune system plays a central role. Interestingly, whatever the defence strategy adopted by the host, this is likely to have an effect on parasite evolution. Given their short generation time and large population size, parasites are expected to rapidly adapt to the environment…
Return flight to the Canary Islands – The key role of peripheral populations of Afrocanarian blue tits (Aves: Cyanistes teneriffae) in multi-gene rec…
2012
Abstract Afrocanarian blue tits (Cyanistes teneriffae) have a scattered distribution on the Canary Islands and on the North African continent. To date, the Canary Islands have been considered the species’ main Pleistocene evolutionary center, but their colonization pathways remain uncertain. We set out to reconstruct a dated multi-gene phylogeny and ancestral ranges for Cyanistes tit species including the currently unstudied, peripheral Libyan population of C. t. cyrenaicae. In all reconstructions the most easterly and westerly peripheral populations (in Libya and on La Palma) represented basal offshoots of C. teneriffae. These two peripheral populations shared all four major indels and dif…
L'influence de l'hyperthyroidisation expérimentale sur le plumage des oiseaux carnivores: (note préliminaire) [Gaļas ēdāju putnu spalvojuma atkarība …
1931
Teksts franču valodā, kopsavilkums latviešu valodā.
Do pollinator distributions underlie the evolution of pollination ecotypes in the Cape shrub Erica plukenetii?
2013
Background and aims According to the Grant-Stebbins model of pollinator-driven divergence, plants that disperse beyond the range of their specialized pollinator may adapt to a new pollination system. Although this model provides a compelling explanation for pollination ecotype formation, few studies have directly tested its validity in nature. Here we investigate the distribution and pollination biology of several subspecies of the shrub Erica plukenetii from the Cape Floristic Region in South Africa. We analyse these data in a phylogenetic context and combine these results with information on pollinator ranges to test whether the evolution of pollination ecotypes is consistent with the Gra…
FLIES AS POLLINATORS OF MELITTOPHILOUS SALVIA SPECIES (LAMIACEAE)
2014
UNLABELLED • PREMISE OF THE STUDY Floral adaptation to a functional pollinator group does not necessarily mean close specialization to a few pollinator species. For the more than 950 species of Salvia, only bee and bird pollinations are known. Restriction to these pollinators is mainly due to the specific flower construction (lever mechanism). Nevertheless, it has been repeatedly suggested that Salvia flowers might also be pollinated by flies. Are flies able to handle the lever mechanism? Are they functionally equivalent pollinators? In this study, we compared and quantified pollen transfer by bees and flies to test whether flies are true pollinators in Salvia.• METHODS We identified pollin…
Effects of forest patch size on physiological stress and immunocompetence in an area-sensitive passerine, the Eurasian treecreeper ( Certhia familiar…
2004
We manipulated the primary brood size of Eurasian treecreepers (Certhia familiaris) breeding in different sized forest patches (0.5-12.8 ha) in moderately fragmented landscapes. We examined the effects of brood size manipulation (reduced, control, enlarged) and forest patch size on physiological stress (heterophil-lymphocyte ratios; H/L), body condition and cell-mediated immunocompetence (phytohaemagglutinin test). Nestlings' H/L ratios were negatively related to forest patch area in control and enlarged broods, whereas no effects were found in reduced broods. The effects of forest patch area were strongest in enlarged broods, which had, in general, twofold higher H/L ratios than control an…
Zur Morphologie des embryonalen Meckelschen Knorpels der Vögel [Putnu embrionālā Meckela skrimšļa morfoloģija]
1933
Teksts vācu valodā, kopsavilkums latviešu valodā.
Investigation of superspreading COVID-19 outbreak events in meat and poultry processing plants in Germany: A cross-sectional study.
2020
Since May 2020, several COVID-19 outbreaks have occurred in the German meat industry despite various protective measures, and temperature and ventilation conditions were considered as possible high-risk factors. This cross-sectional study examined meat and poultry plants to examine possible risk factors. Companies completed a self-administered questionnaire on the work environment and protective measures taken to prevent SARS-CoV-2 infection. Multivariable logistic regression analysis adjusted for the possibility to distance at least 1.5 meters, break rules, and employment status was performed to identify risk factors associated with COVID-19 cases. Twenty-two meat and poultry plants with 1…