37 research outputs found
Multiple habitat use by declining migratory birds necessitates joined-up conservation
Many species depend on multiple habitats at different points in space and time. Their effective conservation requires an understanding of how and when each habitat is used, coupled with adequate protection. Migratory shorebirds use intertidal and supratidal wetlands, both of which are affected by coastal landscape change. Yet the extent to which shorebirds use artificial supratidal habitats, particularly at highly developed stopover sites, remains poorly understood leading to potential deficiencies in habitat management. We surveyed shorebirds on their southward migration in southern Jiangsu, a critical stopover region in the East Asian Australasian Flyway (EAAF), to measure their use of artificial supratidal habitats and assess linkages between intertidal and supratidal habitat use. To inform management, we examined how biophysical features influenced occupancy of supratidal habitats, and whether these habitats were used for roosting or foraging. We found that shorebirds at four of five sites were limited to artificial supratidal habitats at high tide for ~11-25 days per month because natural intertidal flats were completely covered by seawater. Within the supratidal landscape, at least 37 shorebird species aggregated on artificial wetlands, and shorebirds were more abundant on larger ponds with less water cover, less vegetation, at least one unvegetated bund, and fewer built structures nearby. Artificial supratidal habitats were rarely used for foraging and rarely occupied when intertidal flats were available, underscoring the complementarity between supratidal roosting habitat and intertidal foraging habitat. Joined-up artificial supratidal management and natural intertidal habitat conservation are clearly required at our study site given the simultaneous dependence by over 35,000 migrating shorebirds on both habitats. Guided by observed patterns of habitat use, there is a clear opportunity to improve habitat condition by working with local land custodians to consider shorebird habitat requirements when managing supratidal ponds. This approach is likely applicable to shorebird sites throughout the EAAF.Micha V. Jackson, Luis R. Carrasco, Chi-Yeung Choi, Jing Li, Zhijun Ma, David S. Melville ... et al
Taxonomic status of the extinct Canary Islands Oystercatcher Haematopus meadewaldoi
Mitochondrial genes were sequenced from four specimens of the extinct Canary Islands Oystercatcher Haematopus meadewaldoi and compared with African Oystercatcher Haematopus moquini, Eurasian Oystercatcher Haematopus ostralegus and an old unidentified extralimital ‘black’ oystercatcher specimen from The Gambia. At these loci, H. meadewaldoi was approximately 99.65% identical to multiple Eurasian Oystercatcher samples and in phylogenetic trees fell within the range of genetic variation observed in that species. The mystery Gambian bird was resolved as an extralimital H. moquini. We conclude that H. meadewaldoi was most likely a recently diverged melanistic morph or subspecies of H.ostralegus, although further genomic studies will be required to determine whether there has been a period of isolation followed by introgression
Magnetic Field Amplification in Galaxy Clusters and its Simulation
We review the present theoretical and numerical understanding of magnetic
field amplification in cosmic large-scale structure, on length scales of galaxy
clusters and beyond. Structure formation drives compression and turbulence,
which amplify tiny magnetic seed fields to the microGauss values that are
observed in the intracluster medium. This process is intimately connected to
the properties of turbulence and the microphysics of the intra-cluster medium.
Additional roles are played by merger induced shocks that sweep through the
intra-cluster medium and motions induced by sloshing cool cores. The accurate
simulation of magnetic field amplification in clusters still poses a serious
challenge for simulations of cosmological structure formation. We review the
current literature on cosmological simulations that include magnetic fields and
outline theoretical as well as numerical challenges.Comment: 60 pages, 19 Figure
European Space Agency experiments on thermodiffusion of fluid mixtures in space
Abstract.: This paper describes the European Space Agency (ESA) experiments devoted to study thermodiffusion of fluid mixtures in microgravity environment, where sedimentation and convection do not affect the mass flow induced by the Soret effect. First, the experiments performed on binary mixtures in the IVIDIL and GRADFLEX experiments are described. Then, further experiments on ternary mixtures and complex fluids performed in DCMIX and planned to be performed in the context of the NEUF-DIX project are presented. Finally, multi-component mixtures studied in the SCCO project are detailed
Whole-genome sequencing reveals host factors underlying critical COVID-19
Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease
Declining adult survival of New Zealand Bar-tailed Godwits during 2005–2012 despite apparent population stability
Like many migratory shorebird populations using the East Asian–Australasian Flyway, Bar-tailed GodwitsLimosa lapponica baueri in New Zealand have significantly declined since the mid-1990s, but census data indicate arelatively stable population since 2004. The demographic drivers of both the decline and stabilisation remain unknown.We estimated annual survival from mark–recapture data of adult godwits in New Zealand during 2005–2014. Annualadult survival declined over the study period from 0.89–0.96 in 2005–2010 to 0.83–0.84 in 2011–2012. The simultaneousdecline in annual survival found in a separate study of Bar-tailed Godwits L. l. menzbieri in north-west Australia suggestsa common effect of their high dependence on threatened migratory staging sites in the Yellow Sea; the more extreme declinein L. l. menzbieri may reflect ecological differences between the populations, such as timing and extent of use of these sites.At current apparent recruitment rates, persistent adult survival of ~0.84 would lead to a population decline of 5–6% per yearin L. l. baueri. Our study implies that the demographic precursors to a population decline developed during a period ofapparent population stability; this suggests that monitoring a single index of population stability is insufficient for predictingfuture trends
Rethinking China’s new great wall : Massive seawall construction in coastal wetlands threatens biodiversity
China’s position as the world’s second largest economy is largely due to its rapid economic growth in the coastal region, which composes only 13% of China’s total land area, yet contributes 60% of the gross domestic product (GDP). To create extra land for the rapidly growing economy, coastal wetlands have been enclosed by thousands of kilometers of seawalls, whose length exceeds that of China’s famous ancient “Great Wall” (see photos and map). This new “Great Wall,” covering 60% of the total length of coast-line along mainland China ( 1), caused a dramatic decline in internationally shared biodiversity and associated ecosystem services and will threaten regional ecological security and sustainable development. Here, we outline these problems, analyze the drivers behind wetland reclamation, and propose measures for effective wetland management