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Status of migratory wader populations in Africa and Western Eurasia in the 1990s

  • Nick Davidson Environmental


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... those IBAs that are not covered by protected areas) wetlands supported the greatest number of wintering waterbirds throughout Europe and North Africa in the past 26 years, especially in C and NE Europe. This finding was expected given that the IBA criteria include thresholds based on the abundance of aggregative species such as waterbirds (Donald et al., 2018), and many PAs may have been designated on the basis of the waterbird populations that they support (Gleason et al., 2011;Green and Elmberg, 2014;Stroud et al., 2004). Unlisted wetlands (not identified as IBA nor formally designated as PA) hosted the lowest abundance of winter Pavón-Jordán et al. ...
... Nevertheless, the increase in the abundance outside protected areas has direct conservation implications. One of the criteria for designation of sites as protected areas under the Ramsar Convention and the EU Birds Directive is the presence of 1% of the biogeographical population of a species of conservation concern (Méndez et al., 2018;Stroud et al., 2004). Hence, some wetlands may gain conservation importance (and qualify for a legally protected area) if the numbers of such species increase due to the shifts while others might no longer qualify as IBA, typically at the SW edge of the distribution Johnston et al., 2013;Méndez et al., 2018). ...
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Migratory waterbirds require an effectively conserved cohesive network of wetland areas throughout their range and life-cycle. Under rapid climate change, protected area (PA) networks need to be able to accommodate climate driven range shifts in wildlife if they are to continue to be effective in the future. Thus, we investigated geographical variation in the relationship between local temperature anomaly and the abundance of 61 waterbird species during the wintering season across Europe and North Africa during 1990-2015. We also compared the spatio-temporal effects on abundance of sites designated as PAs, Important Bird and Biodiversity Areas (IBAs), both, or neither designation (Unlisted). Waterbird abundance was positively correlated with temperature anomaly , with this pattern being strongest towards north and east Europe. Waterbird abundance was higher inside IBAs, whether they were legally protected or not. Trends in waterbird abundance were also consistently more positive inside both protected and unprotected IBAs across the whole study region, and were positive in Unlisted wetlands in southwestern Europe and North Africa. These results suggest that IBAs are important sites for wintering waterbirds, but also that populations are shifting to unprotected wetlands (some of which are IBAs). Such IBAs may, therefore, represent robust candidate sites to expand the network of legally protected wetlands under climate change in northeastern Europe. These results underscore the need for monitoring to understand how the effectiveness of site networks is changing under climate change.
... A few decades ago, the estimated global population amounted to more than two million individuals distributed over a wide winter range (Zwarts et al. 2009). Across this range, birds from two major flyway populations occur (Stroud et al. 2004): a West-African population, which includes European winterers, and an East-African population, which includes Indian and South-African winterers. Several hundred thousand male and female Ruffs winter in floodplains, river sides and lakes in sub-Saharan Africa (reviewed in Cramp & Simmons 1983, Zwarts et al. 2009, Vervoort 2019, while fewer than 10,000 individuals, predominantly males, winter north of the Sahara, in wetlands and wet agricultural areas of the Mediterranean basin, and along the Atlantic Ocean and North Sea coasts (reviewed in Scheufler & Stiefel 1985, van Gils & Wiersma 1996. ...
... In the European part of the wintering range, the population increased from 1979 to the mid-1990s with stabilization or a slow decline afterwards; in African wintering areas, the species shows a sustained decline at an annual rate of 1% (van Roomen et al., 2015). In the 1990s, the overall wintering population size was estimated to be 250,000 birds (Stroud et al., 2004). In 2015, a population size of 200,000 was estimated, reflecting the population decrease between the mid-1990s and 2014 by c. 20% (van Roomen et al., 2015). ...
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Kolguev Island (69˚05′ N 49˚15′ E) is located in the Pechora Sea, the southeastern part of the Barents Sea. The island’s ecosystem is unusual due to the total absence of rodents and specialized predators such as weasels, while non-specialized predators such as Arctic (Vulpes lagopus) and red (V. vulpes) foxes and Rough-legged Hawk (Buteo lagopus) are common. Currently, 111 bird species have been registered here, of which 58 are nesting. The absence of rodents and the relatively stable predation pressure have resulted in the high abundance of many bird species: Willow Ptarmigan (Lagopus lagopus), several goose species, some waders, and passerines. Over the 125-year history of ornithological studies on Kolguev, the island avifauna has changed significantly. The trend of an increase in the proportion of widespread and Siberian species together with a decrease in the proportion of Arctic species was observed. Since 2006, a thorough monitoring of Kolguev avifauna has been carried out, during which the dynamics of the bird population densities have been traced. The abundance of Black-bellied Plover (Pluvialis squatarola) and Dunlin (Calidris alpina) decreased, while the numbers of Barnacle Goose (Branta leucopsis) have increased sharply since the 1980s. The breeding density of Rough-legged Hawk has also increased in recent years. The long-term monitoring of Kolguev ecosystems has indicated the high international conservation value of the island due to the high breeding density of many bird species. Our study, covering more than a century of avifaunal studies with almost annual monitoring over the past three decades, provides an unusually long and detailed time-series for an Arctic island.
... This is further compounded by the fact that standardized counts are restricted to larger lakes, while breeding might be spread out in smaller temporary waterholes (e.g., Baker 1996, Lewis 1989. The size of the resident population in East Africa was recently revised from 25 000-100 000 (Delany et al. 2009, Stroud et al. 2004 to 20 000-50 000 (Dodman 2014). The initial estimate is mainly based on the mention of "45 000 or more on some Kenyan lakes" by Hayman (1986), yet as such a record cannot be verified, it is treated with caution here in the light of other historical counts (see below). ...
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Several populations of Pied Avocet are understood to overlap in East Africa, yet the specific movements and size of each of them remains largely unclear. A review of current literature, combined with waterbird counts and recent citizen science data, suggests that potentially three populations occur in the region (Palaearctic, southern origin, and resident), and that the resident population is substantially smaller than previous estimates suggested. A new breeding record at the Kenyan coast, which only constitutes the fourth confirmed breeding location of Pied Avocet in Kenya and the first for the East African coast, demonstrates a potential overlap of Palaearctic migrants and East African residents, which may breed opportunistically along the coast. More resources are needed to carry out standardized and regular national monitoring counts in order to further elucidate the origin, movement, and numbers of Pied Avocets in East Africa.
... The Southern Dunlin is one of several subspecies of Dunlin that breed across arctic and subarctic tundra, alpine wetlands, and wet grasslands in the temperate zone [43]. In addition to the Baltic region, Southern Dunlins breed in Iceland, British Isles, Faroe Islands and southeastern Greenland with an estimated 970 000-990 000 individuals [18,44]. Their main autumn migration route follows the Atlantic coast of Europe and continues south to the main wintering areas in northwest and northern Africa, where the wintering grounds are shared with the northern subspecies alpina and arctica [39,43,45]. ...
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Background Populations living in fragmented habitats may suffer from loss of genetic variation and reduced between-patch dispersal, which are processes that can result in genetic differentiation. This occurs frequently in species with reduced mobility, whereas genetic differentiation is less common among mobile species such as migratory birds. The high dispersal capacity in the latter species usually allows for gene flow even in fragmented landscapes. However, strongly philopatric behaviour can reinforce relative isolation and the degree of genetic differentiation. The Southern Dunlin ( Calidris alpina schinzii ) is a philopatric, long-distance migratory shorebird and shows reduced dispersal between isolated breeding patches. The endangered population of the Southern Dunlin breeding at the Baltic Sea has suffered from habitat deterioration and fragmentation of coastal meadows. We sampled DNA across the entire population and used 12 polymorphic microsatellite loci to examine whether the environmental changes have resulted in genetic structuring and loss of variation. Results We found a pattern of isolation-by-distance across the whole Baltic population and genetic differentiation between local populations, even within the southern Baltic. Observed heterozygosity was lower than expected throughout the range and internal relatedness values were positive indicating inbreeding. Conclusions Our results provide long-term, empirical evidence for the theoretically expected links between habitat fragmentation, population subdivision, and gene flow. They also demonstrate a rare case of genetic differentiation between populations of a long-distance migratory species. The Baltic Southern Dunlin differs from many related shorebird species that show near panmixia, reflecting its philopatric life history and the reduced connectivity of its breeding patches. The results have important implications as they suggest that reduced connectivity of breeding habitats can threaten even long-distance migrants if they show strong philopatry during breeding. The Baltic Southern Dunlin warrants urgent conservation efforts that increase functional connectivity and gene flow between breeding areas.
... Shorebirds are known for their diverse breeding systems , their immense multispecies migratory congregations (Cestari et al. 2020), and their impressive ability to travel thousands of kilometers before needing to refuel (Gill et al. 2005). However, in recent decades, shorebird populations have experienced a steep population decline (Stroud et al. 2006, Wetlands International 2012. Since the 1970s, 68% of the 52 shorebird species occurring in North America have experienced declines . ...
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The Lesser Yellowlegs (Tringa flavipes) is a migratory shorebird species that has experienced a precipitous population decline. The factors governing this decline are complex and may correspond to habitat traits and migratory dynamics. Recent advancements in GPS telemetry have allowed for a precise description of migratory patterns to interpret the spatial and temporal distributions of migratory bird species compared to prior approaches that used band recoveries, surveys, and morphological measurements. Understanding the similarities and differences in distributions among and within disparate populations of birds is critical for identifying the potential exposure to threats that influence a species’ productivity and survival. Detailed distribution data provides the foundation for the development and implementation of targeted conservation applications for declining species, such as the Lesser Yellowlegs. In 2018, 2019, and 2020, project cooperators and I deployed 110 PinPoint GPS Argos satellite tags on adult Lesser Yellowlegs at six sites spanning the boreal biome of Alaska and Canada. The Lesser Yellowlegs is a Neotropical migrant shorebird that breeds in the boreal forest and spends the winter in Central and South America and the Caribbean. Upon summarizing the locations received, I found that geographically disparate populations followed different routes during autumn migration, but experienced weak migratory connectivity, or high population mixing, at wintering locations. Differentiation in migratory timing, distances, and strategies were also variable among sexes and breeding populations. Further, I described the primary stopover, staging, and wintering sites and determined that the Prairie Pothole region and the Gulf Coast region were the primary stopover sites during autumn and spring migration, whereas northeastern Argentina was the primary wintering area. Within each of those regions, the highest proportion of Lesser Yellowlegs detections were in wetland habitats. Lastly, I modeled the probability of Lesser Yellowlegs occurring within Caribbean and northeastern South American countries where shorebirds are harvested for sport and subsistence. I found that geographically disparate populations were differentially exposed to shorebird harvest. Populations originating from eastern Canada had the highest probability of occurrence and longest duration of stay within harvest zones from mid-August through October, while populations originating from Alaska had an exposure probability of nearly zero throughout the autumn. The Lesser Yellowlegs has experienced a precipitous population decline of ~63% since the 1970s. Within the next decade, it is predicted that an additional 50% of the current population size will be lost if science-driven conservation actions are not practiced. By using real-time location data to identify annual migration patterns and the probabilities of harvest exposure among disparate populations of Lesser Yellowlegs, my thesis provides the knowledge for tailoring conservation priorities and actions for specific geographic regions or subpopulations that are at high risk (e.g. populations originating in eastern Canada). Focusing conservation efforts to areas where scientifically rigorous analyses illustrate serious concern is an effective approach to ensure the perseverance of a steeply declining shorebird.
... Tremendous anthropogenic pressures have caused rapid decline in the wetlands worldwide (Shine, Klemm, 1999), which is responsible for the catastrophic decline in waterbird populations around the world (Stroud et al., 2004;BirdLife International, 2008;Wetlands International, 2012). In India, 69% of the area consists of inland wetlands (Bassi et al., 2014), of which many wetlands are threatened and many are already degraded (Central Pollution Control Board, 2008). ...
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Wetland acts as an important habitat that supports a massive diversity of organisms, especially waterbirds. We examined waterbird diversity and habitat use in relation to abiotic factors at Mavoor and Vazhakkad, two major wetlands in South Western India. The study was from 2015 December to 2016 November. A total of 50 species from Vazhakkad and 40 species from Mavoor wetlands were recorded; 12 species exclusive to Vazhakkad and three to Mavoor. Among them, 16 species were winter visitors in Vazhakkad and nine in Mavoor. Highest diversity of waterbirds was observed in agroecosystem of Vazhakkad. Physico-chemical variables were recorded for the two wetlands and its effect on waterbird richness, abundance, and diversity were correlated. Multivariate test showed the variation in diversity between two wetlands (MANOVA: Wilks’ λ = 0.933, F= 3.69 P = 0.006) and habitat wetland interaction (MANOVA: Wilks’ λ = 0.694, F= 10.25, P = 0.00). Non linear regression analyses were carried out between the evolution of the ecological index in the two wetlands separately. From the study we could conclude the effects of anthropogenic disturbances on wetland function.
... For example, the majority of shorebird species in our data set (n = 11) have reportedly recovered since the 1980s in areas of the African-Eurasian Waterbird Agreement (AEWA 2009). In addition, the proportion of declining populations reduced between two studies in the late 1990s and 2013 ( Stroud et al. 2004Stroud et al. , Zöckler et al. 2013), with around half now considered to be stable ( Zöckler et al. 2013). There are problems with this comparison, however, as some of the difference in proportion may be attributable to differences in species composition between the two studies. ...
Technical Report
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Trend Indices of Arctic Birds using Living Planet Index methodology from 1970s up to 2010. Trend data quality varying also from region to region
... These two wetlands are separated by less than 100 km. Both are important feeding and roosting areas for birds using the East Atlantic Flyway (Sánchez et al., 2006) through which more than 15.5 million shorebirds migrate (Stroud et al., 2004). Dispersal of A. franciscana is strongly favoured by aquatic birds which can transport viable cysts over long distances (Green et al., 2005;Sánchez et al., 2012). ...
Although a substantial amount of research exists on pollution and biological invasions, there is a paucity of understanding of how both factors interact. Most studies show that pollution favours the establishment of invasive species, but pollution may also promote local adaptation of native species and prevent the establishment of new incomers. However, evidence for this is extremely limited because most studies focus on successful invasions and very few on cases where an invasion has been resisted. Here we provide evidence of local adaptation of native species to pollution combining life history and physiological data. We focused on the invasion of the North American brine shrimp Artemia franciscana, which is causing a dramatic biodiversity loss in hypersaline ecosystems worldwide, and one of the last native Artemia populations in SW Europe (A. parthenogenetica from the historically polluted Odiel estuary, SW Spain). Life table response experiments were carried out in the laboratory to compare the demographic responses of A. parthenogenetica and a nearby A. franciscana population to long-term Zn exposure (0.2 mg L−1). We also evaluated oxidative stress by measuring antioxidant defences (catalase, glutathione reductase and superoxide dismutase) and lipid peroxidation (thiobarbituric acid reactive substances). A high concentration of Zn induced strong mortality in A. franciscana, which also showed high levels of lipid peroxidation, suggesting relatively poor physiological resistance to pollution compared with A. parthenogenetica. The age at maturity was shorter in A. parthenogenetica, which may be an adaptation to the naturally high mortality rate observed in the Odiel population. Exposure to Zn accelerated age at first reproduction in A. franciscana but not in A. parthenogenetica. In contrast, Zn had a stimulatory effect on offspring production in A. parthenogenetica,which also showed higher reproductive parameters (number of broods, total offspring and offspring per brood) than A. franciscana. Overall, the results of this study strongly suggest that native Artemia from Odiel estuary is locally adapted (at both, reproductive and physiological levels) to Zn contamination and that A. franciscana is highly sensitive. This is a good example of how pollution may play a role in the persistence of the last native Artemia populations in the Mediterranean.
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Wetlands are important areas in the conservation of biodiversity and play a key role in the ecosystems regulation. Thus, considering that climate change effects combined with anthropogenic pressures on natural resources are causing loss of biodiversity in Sahelian countries such as Senegal, we need to do regular stock assessments. For this, we aimed at studying the Black winged-stilt (Himantopus himantopus himantopus) in the urban wetland of Technopôle in the Niayes of Dakar (capital of the republic of Senegal). Our study is focused on the spatial distribution and nesting of the Black winged-stilt (Himantopus himantopus himantopus) in Technopole, which is classified in the list of Important Bird Areas (IBAs) by Birlife International since 2001 under A4i criteria and is an important biodiversity hotspot. The Niayes of Dakar constitute a particular ecosystem of wetland, they play a determining role in the reproduction and the survival of manies birds' species. The nesting study was conducted from May to August 2012 and from May to August 2017. The maximum numbers of Black winged-stilt count during these periods are 531 individuals for 2012 and 766 individuals for 2017. However we highlight a decrease of the number of Black winged-stilt in the Technopole after the onset of the rains. Breeding data (25 nests in 2012 and 79 in 2017) show that this urban wetland is a preferred nesting site for Black winged-stilt. We report for the first time in this paper, so many Black winged-stilt nests in Senegal. Despite the disturbances related to anthropogenic factors, the breeding success of the Black winged-stilt reached 89.6% in May 2017. Thus, we believe that a strengthening of a conservation action plan of this site is urgent for a better preservation of the biodiversity, particularly the avian resources.
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