Information on migratory pathways and connectivity is essential to understanding population dynamics and structure of migrant species. Our manuscript uses a unique dataset, the fruit of 103 individual Asian houbara bustards captured on their breeding grounds in Central Asia over 15 years and equipped with satellite transmitters, to provide a better understanding of migratory pathways and connectivity; such information is critical to the implementation of biologically sound conservation measures in migrant species. At the scale of the distribution range we find substantial migratory connectivity, with a clear separation of migration pathways and wintering areas between western and eastern migrants. Within eastern migrants, we also describe a pattern of segregation on the wintering grounds. But at the local level connectivity is weak: birds breeding within the limits of our study areas were often found several hundreds of kilometres apart during winter. Although houbara wintering in Arabia are known to originate from Central Asia, out of all the birds captured and tracked here not one wintered on the Arabian Peninsula. This is very likely the result of decades of unregulated off-take and severe habitat degradation in this area. At a time when conservation measures are being implemented to safeguard the long-term future of this species, this study provides critical data on the spatial structuring of populations.
Background: The spread of SARS-CoV-2 in Sub-Saharan Africa is poorly understood and to date has generally been characterised by a lower number of declared cases and deaths as compared to other regions of the world. Paucity of reliable information, with insights largely derived from limited RT-PCR testing in high-risk and urban populations, has been one of the biggest barriers to understanding the course of the pandemic and informed policy-making. Here we estimate seroprevalence of anti-SARS-CoV-2 antibodies in Ethiopia during the first wave of the pandemic. Methods: We undertook a population-based household seroprevalence serosurvey based on 1856 participants in Ethiopia, in the capital city Addis Ababa, and in Jimma, a middle-sized town in the Oromia region, and its rural surroundings (districts of Seka and Mana), between 22 July and 02 September 2020. We tested one random participant per household for anti-SARS-CoV-2 antibodies using a high specificity rapid diagnostic tests (RDTs) and evaluated population seroprevalence using a Bayesian logistic regression model taking into account test performance as well as age and sex of the participants. Findings: In total, 2304 random households were visited, with 1856 individuals consenting to participate. This produced a sample of 956 participants in Addis Ababa and 900 participants in Jimma. IgG prevalence was estimated at 1.9% (95% CI 0.4À3.7%), and combined IgM/IgG prevalence at 3.5% (95% CI 1.7À5.4%) for Addis Ababa in early August 2020, with higher prevalence in central sub-cities. Prevalence in Jimma town was lower at 0.5% (95% CI 0À1.8%) for IgG and 1.6% (95%CI 0À4.1%) for IgM/IgG, while in rural Jimma IgG prevalence was 0.2% and IgM/IgG 0.4% in early September. Interpretation: More than four months after the first cases were detected in Ethiopia, Addis Ababa displayed a prevalence under 5% and likely as low as 2%, while rural Jimma displayed a prevalence of 0.2%. A 2% seroprevalence figure for the capital translated to a number of cases at least five times larger than those reported for the country as a whole. At the same time, it contrasts with significantly higher seroprevalence figures in large cities in Europe and America only two to three months after the first cases. This population-based seroepidemiological study thus provides evidence of a slower spread of SARS-CoV-2 in the Ethiopian population during the first wave of the pandemic and does not appear to support the notion that lower case numbers were simply a reflection of limited testing and surveillance.
Whereas some bird species are heavily affected by blood parasites in the wild, others reportedly are not. Seabirds, in particular, are often free from blood parasites, even in the presence of potential vectors. By means of polymerase chain reaction, we amplified a DNA fragment from the cytochrome b gene to detect parasites of the genera Plasmodium, Leucocytozoon, and Haemoproteus in 14 seabird species, ranging from Antarctica to the tropical Indian Ocean. We did not detect parasites in 11 of these species, including one Antarctic, four subantarctic, two temperate, and four tropical species. On the other hand, two subantarctic species, thin-billed prions Pachyptila belcheri and dolphin gulls Larus scoresbii, were found infected. One of 28 thin-billed prions had a Plasmodium infection whose DNA sequence was identical to lineage P22 of Plasmodium relictum, and one of 20 dolphin gulls was infected with a Haemoproteus lineage which appears phylogenetically clustered with parasites species isolated from passeriform birds such as Haemoproteus lanii, Haemoproteus magnus, Haemoproteus fringillae, Haemoproteus sylvae, Haemoproteus payevskyi, and Haemoproteus belopolskyi. In addition, we found a high parasite prevalence in a single tropical species, the Christmas Island frigatebird Fregata andrewsi, where 56% of sampled adults were infected with Haemoproteus. The latter formed a monophyletic group that includes a Haemoproteus line from Eastern Asian black-tailed gulls Larus crassirostris. Our results are in agreement with those showing that (a) seabirds are poor in hemosporidians and (b) latitude could be a determining factor to predict the presence of hemosporidians in birds. However, further studies should explore the relative importance of extrinsic and intrinsic factors on parasite prevalence, in particular using phylogenetically controlled comparative analyses, systematic sampling and screening of vectors, and within-species comparisons.
Impacts of anthropogenic climate change on marine ecosystems are now widely acknowledged. In the NE Atlantic, abundant evidence from the partly enclosed waters of the North Sea indicates that recent climate-induced changes in primary and secondary productivity have been propagated up the food chain, with marked consequences for higher vertebrate predators such as seabirds. In contrast, however, there is much less indication of such impacts on higher predators in the more open Atlantic waters around the west coast of the British Isles. Through an annual comparison of chick growth and adult food provisioning behaviour of Manx shearwaters in SW Wales, we found that birds bred later and chicks attained lower peak and fledging masses in 2007 and 2008 than in any previous recorded year dating back to 1965. These changes were accompanied by a reduction in parental attendance at the colony, which was probably the result of parents switching to a dual foraging strategy in 2007 and 2008. These events were linked to higher sea surface temperature in the preceding winter and to a reduction in prey quality, as indicated by the mean body mass of 2 yr old herring. These are the first such findings for the west coast of Britain and indicate that within the NE Atlantic region, adverse impacts of climate change on higher marine predators are no longer restricted to the vicinity of the North Sea.
SummaryA sharp decline in the numbers of Asian Houbara Bustard Chlamydotis macqueenii towards the end of the 20 th century raised concerns about the conservation status of this species. Yet due to its large breeding range in the remote steppes and deserts of Central Asia and to its cryptic behaviour, it has been difficult to obtain enough comparable data to make reliable estimates of population trends. Here, we present the results of 10 years of extensive biannual surveys throughout southern Kazakhstan, considered to host the majority of the breeding birds in Asia, and we discuss trends in the Kazakh populations for the first decade of this century. The breeding Houbara population has generally declined over the greater part of Kazakhstan between 2000 and 2009 but with important regional differences. A steep decline was observed in north-east Caspian and Karakum, and a sharp drop followed by a stabilisation occurred in Kyzylkum. Over the same period, estimated densities were stable or increased in the area surrounding Lake Balkash, and increased in the Betpak-Dala region of central Kazakhstan. Autumn surveys showed more variability and revealed little decline overall. It was also clear that Betpak-Dala and Balkash regions hosted the largest populations. Our findings suggest that it is a complex undertaking to assign a level of vulnerability for this species as a whole. Highly variable population trends between regions indicate that threats and pressures are to a considerable extent region-specific, and that conservation measures need to be adjusted locally.
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