Migratory Waterbird Species Research Articles

Metagenomic analysis of the gut microbiota of hooded cranes (Grus monacha) on the Izumi plain in Japan.

Recent advances in DNA sequencing technology have dramatically improved our understanding of the gut microbiota of various animal species. However, research on the gut microbiota of birds lags behind that of many other vertebrates, and information about the gut microbiota of wild birds such as migratory waterfowl is particularly lacking. Because the ecology of migratory waterfowl (e.g., lifestyle, diet, physiological characteristics) differs from that of other birds, the gut microbiota of migratory waterfowl likely also differs, but much is still unknown. The hooded crane (Grus monacha) is an important representative migratory waterbird species and is listed as endangered on the International Union for Conservation of Nature and Natural Resources Red List of Threatened Species. In this study, we analyzed the bacterial and viral microbiota in the gut of hooded cranes by using deep sequencing data from fecal samples of hooded cranes that winter on the Izumi plain in Japan, and found that Cetobacterium, Clupeiformes, and Pbunavirus were clearly present in the fecal samples of hooded cranes. These findings advance our understanding of the ecology of hooded cranes.

Influence of water physico‐chemical parameters on the spatio‐temporal activity variations of west African waterbirds (fam. Ardeidae)

AbstractVariations in physico‐chemical parameters of water as abiotic factors affect the spatio‐temporal distributions of the organisms that live in it. The present study aims to determine the influence of physico‐chemical properties on Ardeidae spatio‐temporal variations in the wetland of Ramsar site 1018 in Benin. To reach this goal, transect enumeration techniques and stationary counts lasting 15–30 min were used to count Ardeidae species once a month at different sites such as Nokoué Lake, Sô River, Porto‐Novo Lagoon, Ouémé River and ancient Lagoons from January 2015 to December 2016. Water physico‐chemical parameters were measured at three stations per site during the bird counts. Five of the 12 species recorded monthly were significantly influenced (p < 0.05) by water physico‐chemical parameters. It was then revealed that pH influenced Ardeidae spatial variation. Such information is relevant to the management of Ramsar Site 1018, which hosts migratory waterbird species from Palearctic (Eurasia) every year.

Spatiotemporal variations in migratory bird diversity and abundance along the coast of Gochang getbol.

Tidal flats provide critical habitat for migratory waterbird species; however, populations of migratory waterbirds have significantly declined due to tidal flat loss and degradation caused by human activities, particularly in Asia. Gochang getbol is one of tidal flats located on the southwest coast of South Korea and a center of clam production. Using bird monitoring data collected at five zones (zone1 to zone5) established across Gochang getbol and near coastal area, we examined distribution patterns of migratory bird diversity and conservation-related species along the coast of Gochang getbol. The intensity of human activity ‒ mudflat culture (mostly bivalve) and aquaculture was relatively high at zone2 and zone3, occupying > 30% of 2km circular area surrounding most sample points of these zones. Zone1 and particularly zone4 contained more natural/semi-natural habitats (less disturbed mudflats and wetlands) and zone5 had smallest mudflat than others. Shannon diversity, species richness, and abundance of migratory birds differed between zones (Anova test, P ≤ 0.02) except Shannon diversity in winter. In fall, all values were higher at zone4 than zone3 and zone5. In winter, zone1 showed greatest species richness and higher abundance than zone2, zone3, and zone5. In spring, while most differences were found between zone4 and zone5, abundance at zone4 was somewhat higher than zone2. The results from the fourth corner analysis indicated that abundance of species foraging at mudflat level was positively associated with zone1 (winter) but negatively with zone3 (fall). Sandpipers were positively associated with zone4. Abundance distribution maps of conservation-related species, created by inverse distance-weighted interpolation modeling, also showed high abundance of most conservation-related species at zone4 and 1. The findings of our study suggest the importance of natural/semi-natural habitat, and the possible link between human activity and distribution patterns of migratory birds in Gochang getbol. While we need further investigation on direct response of migratory birds to human activity, areas with low human activity with more natural/semi-natural habitat, e.g., zone4 and zone1 may be crucial for the conservation of migratory birds.

Inventory of Migratory Water birds in the coastal areas of Purba Medinipur district, West Bengal, India.

The present study was done on migratory water birds in the coastal and surrounding areas of Purba Medinipur, West Bengal, India from July 2020 to June 2022. A total number of 51 migratory water bird species belonging to 7 orders and 10 families were recorded during this study. Among the recorded species 45 species were the Least Concern (LC) and 4 were Near Threatened (NT) and 1 species each were Vulnerable (VU) and Endangered (EN). Scolopacidae was represented as highest family of 16 species because aggregation of migratory waders birds during winter season. The overall Shannon Diversity Index (H’) was 0.892 and the Shannon Evenness (J’) value was 0.226. The Simpson’s Diversity Index (D) was 0.286. All the diversity Index were lowest because of dominating Lesser Whisting-duck Dendrocygna javanica (Horsfield, 1821) (9015) aggregate in the coastal wetlands and bheries during winter season. In future more focus will be on this areas as there are many places still not properly explored and several wetlands which need to be studied in a thorough manner for a better understanding about the migratory avian diversity of this area.

Impacts of climate‐driven changes in habitat phenology on dynamics of niche overlaps and spatial associations in a boreal waterbird community

A fundamental, yet little‐explored, question is if climate change has affected niche relationships and spatial associations of native non‐invasive species in established local communities, potentially affecting interspecific interactions and community organization. Here, long‐term (1991‒2020) changes in habitat niche overlaps (HNOs; measured in terms of three habitat categories describing the amount and development of shore vegetation and shore depth) and spatial associations (SAs; measured as co‐occurrence on lakes) were studied in relation to climate‐driven changes in habitat phenology in a community of eight migratory waterbird species breeding on 37 lakes in southeastern Finland. Overall timing of ice‐out date (IOD) and within‐season variation in the timing of ice‐out (standard deviation of IOD, SDIOD) in lakes determine habitat (lake) availability for waterbirds during the settling phase. Previous work has documented that IOD has advanced and SDIOD increased during 1991‒2020, with species responding differently to these changes in their habitat use. HNO and SA varied considerably in the 28 species pairs of eight species during the study period. The effect of IOD and SDIOD on that variation was generally small, effect sizes differing from zero only in eight out of 112 cases. However, the direction and magnitude of the effects of IOD and SDIOD on HNO and SA varied considerably among the species pairs. Although not statistically significant, overall differences in the direction and magnitude of the effect sizes suggested that the impacts of IOD and SDIOD on HNO and SA were stronger in species pairs in which the species were more similar in terms of settling phenology, and stronger for early settling species than for late settling species. Observed changes in niche relationships probably reflect changes in interspecific interactions and affect the possibilities for heterospecific information use in habitat selection.

Remote and local threats are associated with population change in Taiwanese migratory waterbirds

Although several countries along the East Asian-Australasian Flyway have recently begun reporting population trends and identifying threats to migratory waterbirds, there remains rather sparse geographical coverage of systematic waterbird monitoring, impeding our understanding of the flyway-wide status of waterbird populations. To fill this gap, we used the data from a nationwide citizen science project, the “Taiwan New Year Bird Count'' to examine recent population trends of 31 migratory waterbird species across Taiwan, and within three of its waterbird hotspot regions, between 2014 and 2021. Island-wide, the abundance of two species declined significantly while five species increased. However, there was substantial heterogeneity in population trends among regions, with nine species declining significantly in Yi-Lan, four species in Chang-Hua and one species in Chia-Nan. Conversely, 11 species increased significantly in Chia-Nan, one species in Chang-Hua, but no species increased in Yi-Lan. This suggests that a combination of local and remote factors is driving population change in Taiwanese migratory waterbirds. Moreover, species that use local rice paddies or are dependent on tidal flats around the Yellow Sea were more likely to show population declines, and those able to use aquacultural wetlands showed growth. These results suggest that recent rice paddy loss and habitat loss in the Yellow Sea have been contributing to migratory waterbird declines in Taiwanese wetlands. Our findings suggest that local land use planning policies within Taiwan as well as mitigation of Yellow Sea tidal flat loss are likely to be complementary in safeguarding the future of migratory waterbirds in Taiwan.

The Hwaseong Wetlands Reclamation Area and Tidal Flats, Republic of Korea: A Case of Waterbird Conservation in the Yellow Sea

The reclamation of tidal flats is implicated in the declines of a large number of migratory waterbird species along the East Asia-Australasian Flyway, and has resulted in the assessment of Yellow Sea tidal flats as an Endangered habitat by the IUCN. Created in their present form by large-scale reclamation, the Hwaseong Wetlands on the Yellow Sea coast of the Republic of Korea are comprised of tidal flats, a large reclamation lake, and extensive areas of rice-fields and fallow land. As part of preparation for increased protections for these wetlands, we conducted bird surveys between late June 2020 and mid-June 2021. During this period, we recorded more than 150,000 waterbirds in the wetland and concentrations of 1% or more of 25 populations of waterbird. We also recorded a total of 16 globally threatened wetland species. As at many other coastal wetlands in the Yellow Sea, tidal flat obligate waterbird species used the tidal flats for foraging; and roosted in artificial wetlands which had been created through the reclamation process. The extensive areas of rice-field and other freshwater habitats in the Hwaseong Wetlands were also internationally important in their own right, supporting globally threatened amphibians and internationally important concentrations of foraging geese and floodplain-associated waterbird species. The movements of waterbirds between foraging and roosting areas we recorded make clear that conservation of the site’s biodiversity either as a Ramsar site or within a serial World Heritage Property would require protection of all the contiguous tidal flats and also of the most biodiverse rice-field and freshwater wetland areas. As elsewhere in the coastal zone of the Republic of Korea, this would first require the support of local stakeholders and also a reduction in jurisdictional issues between various local and national decision-making bodies.

Balancing future renewable energy infrastructure siting and associated habitat loss for migrating whooping cranes

The expansion of human infrastructure has contributed to novel risks and disturbance regimes in most ecosystems, leading to considerable uncertainty about how species will respond to altered landscapes. A recent assessment revealed that whooping cranes (Grus americana), an endangered migratory waterbird species, avoid wind-energy infrastructure during migration. However, uncertainties regarding collective impacts of other types of human infrastructure, such as power lines, variable drought conditions, and continued construction of wind energy infrastructure may compromise ongoing recovery efforts for whooping cranes. Droughts are increasing in frequency and severity throughout the whooping crane migration corridor, and the impacts of drought on stopover habitat use are largely unknown. Moreover, decision-based analyses are increasingly advocated to guide recovery planning for endangered species, yet applications remain rare. Using GPS locations from 57 whooping cranes from 2010 through 2016 in the United States Great Plains, we assessed habitat selection and avoidance of potential disturbances during migration relative to drought conditions, and we used these results in an optimization analysis to select potential sites for new wind energy developments that minimize relative habitat loss for whooping cranes and maximize wind energy potential. Drought occurrence and severity varied spatially and temporally across the migration corridor during our study period. Whooping cranes rarely used areas <5 km from human settlements and wind energy infrastructure under both drought and non-drought conditions, and <2 km from power lines during non-drought conditions, with the lowest likelihood of use near wind energy infrastructure. Whooping cranes differed in their selection of wetland and cropland land cover types depending on drought or non-drought conditions. We identified scenarios for wind energy expansion across the migration corridor and in select states, which are robust to uncertain drought conditions, where future loss of highly selected stopover habitats could be minimized under a common strategy. Our approach was to estimate functional habitat loss while integrating current disturbances, potential future disturbances, and uncertainty in drought conditions. Therefore, dynamic models describing potential costs associated with risk-averse behaviors resulting from future developments can inform proactive conservation before population impacts occur.

Seasonal Abundance and Diversity of Waterbirds of Rapti river from Sauraha to Kasara of Chitwan National Park, Nepal

Wetlands are the most productive areas for biodiversity and local livelihood support. Waterbirds are important components of most wetland environments. These asonal abundance and diversity of waterbirds of the Rapti River was studied to assess the species composition and richness along with their seasonal variation in August 2017 and January 2018. The fixed-line transect method in a wooden dugout canoe was used for bird sampling between the winter and summer seasons. Total of 51 species of birds belonging to 9 orders and 18 families were recorded. Species richness was high in winter season than in summer. The study revealed that the study site harbors many residents and a few migratory water bird species. According to the IUCN Red List status, 43 species were in the Least Concern, 5species were in the Near Threatened, 2 species were invulnerable, and 1 species was in the Endangered category. The order Anseriformes and Charadriiformes were recorded the much in number that was 11 species each. The dominant family was Anatidae represented by 11 species, followed by the Ardeidae with nine species and the lowest representations of one species were in the other nine families. The Shannon wiener diversity index was found to be higher in the winter season (H’= 3.47) than in the summer season (H’= 3.30). High altitude winter migratory bird Bar-headed Goose (Anser indicus) was also recorded. The major threats to wetland birds included habitat destruction, human disturbances, and fishing. The study concludes that study area contains a diverse and rich avifauna, especially the population of winter migrants that needs to be monitored regularly.

Annual variation in waterbird clutch initiation date in relation to spring thaw in Arctic Russia.

To test for the degree of species-specific variation in clutch initiation date in relation to spring thaw, we recorded first egg dates in 1433 nests of seven large bodied long-distance migratory waterbird species breeding on Ayopechan Island in the Chaun Delta, Chukotka, in the Russian Arctic during 2002-2020. Pacific Loon Gavia pacifica, Sandhill Crane Grus canadensis and Glaucous Gull Larus hyperboreus all adjusted timing of clutch initiation completely to annual variation in first frost-free dates. First egg dates of Spectacled Eider Somateria fischeri also significantly advanced in warmer springs, but the rate of change was significantly less than unity, implying a reduced capacity to accommodate change in vernal thaw that may not be able to keep up with greater change in the future. Long-tailed Duck Clangula hyemalis and Vega Gull Larus vegae showed a tendency for earlier first egg dates in years with earlier first frost-free date, but for both species, the relationship failed to reach statistical significance. Bewick's Swan Cygnus columbianus showed almost no change in mean first egg date across the observed variation in first frost-free dates. Based on these data, we suggest that while all seven species showed signs of plasticity in their timing of onset of breeding, Pacific Loon, Sandhill Crane and Glaucous Gull showed greater adaptability to adjust the timing of their breeding season to recent variation in spring thaw than the other four species studied here over this period.

Development and validation of a highly effective analytical method for the evaluation of the exposure of migratory birds to antibiotics and their metabolites by faeces analysis

The widespread occurrence of antibiotics in the environment may exert a negative impact on wild organisms. In addition, they can become environmental reservoirs, through the ingestion of food or contaminated water, and vectors for antibiotic-resistant bacteria. This fact is even more important in migratory birds that can promote their dissemination across continents. In this work, a multiresidue analytical method suitable for the determination of five families of antibiotics and their main metabolites in waterbird faeces has been developed and validated. The target compounds include environmentally significant sulfonamides, macrolides, fluoroquinolones, tetracyclines and antifolates. Sample treatment involves ultrasound-assisted extraction with methanol and dispersive solid-phase extraction clean-up with C18. Analytical determination was carried out by liquid chromatography–tandem mass spectrometry. The most significant parameters affecting sample extraction and extract clean-up were optimised by means of experimental designs. Good linearity (R2 > 0.994), accuracy (from 41 to 127%), precision (relative standard deviation lower than 24%) and limits of quantification (lower than 2 ng g−1 (dry weight, dw)) were obtained for most of the compounds. The method was applied to the determination of the selected compounds in 27 faeces samples from three common migratory waterbird species. Nine antibiotics and three of their metabolites were detected in the analysed samples. Fluoroquinolones and macrolides were the antibiotics most frequently detected. The highest concentrations corresponded to norfloxacin (up to 199 ng g−1 dw).Graphical abstract

Conserving migratory waterbirds and the coastal zone: the future of South-east Asia's intertidal wetlands

AbstractSouth-east Asia's diverse coastal wetlands, which span natural mudflats and mangroves to man-made salt pans, offer critical habitat for many migratory waterbird species in the East Asian–Australasian Flyway. Species dependent on these wetlands include nearly the entire population of the Critically Endangered spoon-billed sandpiper Calidris pygmaea and the Endangered spotted greenshank Tringa guttifer, and significant populations of several other globally threatened and declining species. Presently, more than 50 coastal Important Bird and Biodiversity Areas (IBAs) in the region (7.4% of all South-east Asian IBAs) support at least one threatened migratory species. However, recent studies continue to reveal major knowledge gaps on the distribution of migratory waterbirds and important wetland sites along South-east Asia's vast coastline, including undiscovered and potential IBAs. Alongside this, there are critical gaps in the representation of coastal wetlands across the protected area networks of many countries in this region (e.g. Viet Nam, Indonesia, Malaysia), hindering effective conservation. Although a better understanding of the value of coastal wetlands to people and their importance to migratory species is necessary, governments and other stakeholders need to do more to strengthen the conservation of these ecosystems by improving protected area coverage, habitat restoration, and coastal governance and management. This must be underpinned by the judicious use of evidence-based approaches, including satellite-tracking of migratory birds, ecological research and ground surveys.

Climate change exposure of waterbird species in the African-Eurasian flyways

SummaryClimate change presents a particularly complex challenge in the context of flyway scale conservation of migratory bird species as it requires coordinated action by multiple countries along these species’ migratory routes. Coordinating conservation responses requires understanding the vulnerability of species and their habitats to climate change at the flyway scale throughout each species’ annual cycle. To contribute to such understanding, we used species distribution models to assess the exposure to climate change of waterbird species that are the focus of the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA). We found that the species with the smallest proportion of their current range projected to be climatically suitable by 2050 (those whose distributions respond to changes in water availability but that do not perform synchronised migration) are dispersive species in the Afrotropical biogeographic realm, and migratory species in their breeding season, particularly Arctic breeding waders. These species also have the most limited availability of newly suitable areas. Projections for most other Palearctic migratory waterbird species suggest that losses of suitable areas in their current passage and wintering ranges may be largely offset by new areas becoming climatically suitable. The majority of migratory Palearctic waterbirds in the breeding season and Afrotropical waterbirds are widely dispersed with only a small proportion of their populations currently supported by ‘Critical Sites’ (i.e. sites that are either important for Globally Threatened Species or support 1% of the bioregional population of any waterbird species). This makes it unlikely that climate change adaptation measures focusing only on key sites will be sufficient to counter the predicted range losses. Therefore, climate change adaptation responses should also be implemented at the landscape scale for Afrotropical waterbirds and for breeding populations of Palearctic migrant waterbirds.

Community-based conservation with formal protection provides large collateral benefits to Amazonian migratory waterbirds.

Populations of migratory waterbirds are facing dramatic declines worldwide due to illegal hunting, habitat loss and climate change. Conservation strategies to reverse these trends are imperative, especially in tropical developing countries, which almost invariably allocate insufficient levels of investment for environmental protection. Here, we compared the effectiveness of sustainable-use Protected Areas (PAs) and Community-based Conservation (CBC) arrangements for the conservation of migratory waterbirds that breed on seasonal riverine sandy beaches in Brazilian Amazonia. We modeled local population responses of four migratory waterbird species on 155 beaches along a ~1,600 km section of a major tributary of the Amazon, as a function of community enforcement, official protection status, human pressure and landscape features. We show that 21 community-protected beaches within the study area host more than 80% of all sampled birds. Black Skimmers showed the most dramatic response, with breeding numbers 135-fold larger in CBC arrangements compared to beaches with no official protection status. The same pattern was observed for nesting Large-Billed and Yellow-Billed Terns. For the Near Threatened Orinoco Goose, PA status was the strongest predictor of local population size. These dramatic results demonstrate the value of protected refugia, achieved through the concerted action of participating local communities, to support breeding populations of key waterbird species. This highly-effective and low-cost conservation model can potentially be replicated in other regions of the developing world experiencing increasingly intensive exploitation of riverine natural resources.

Effects of Food Changes on Intestinal Bacterial Diversity of Wintering Hooded Cranes (Grus monacha).

Simple SummaryThe intestinal microbiota plays a vital role in the health of animals, and food is an important factor that influences the intestinal microbial community. During the winter months, waterbirds require certain foods to supply them with energy through the cold winter. Due to changes in the plant resources available to waterbirds, their intestinal bacteria will vary accordingly. In this study, we analysed the relationship between food composition and intestinal bacteria in hooded cranes (Grus monacha). We found that food resources from similar habitats were more similar, and the corresponding hooded crane intestinal bacteria were also more similar. The results show that the intestinal bacteria of hooded cranes had a certain adaptability to the type of food being consumed. This study contributes novel insights into the diet of hooded cranes in the winter months, allowing for improved protection and management strategies.As food is recognised as an important factor affecting the intestinal microbiota, seasonal changes in diet can influence the community composition. The hooded crane (Grus monacha) is an endangered migratory waterbird species, with some of the population wintering in the sallow lakes in the middle and lower Yangtze River floodplain. Their food resources have changed seasonally, with a reduction resulting from wetland degradation. To cope with seasonal changes in food availability, hooded cranes must constantly adjust their foraging strategies to survive. We studied the effect of changes in diet on the intestinal bacterial diversity of hooded cranes at Shengjin Lake, using faecal microanalysis and high-throughput sequencing. The results show that the main foods of hooded cranes were Polygonum criopolitanum, Oryza sativa, and Carex spp., which were significantly related to the composition of the intestinal bacterial community. In addition, foods available from the similar habitats were more similar, and the corresponding hooded crane intestinal bacteria were also more similar. The relative abundance of Lactobacillus acidipiscis in January and March was significantly higher than in November. Our research shows that the intestinal bacteria of hooded cranes actively adapt to diet changes to overcome the negative impact of the reduction in food resources, which is vital to the survival of hooded cranes.

Consistent choice of landscape urbanization level across the annual cycle in a migratory waterbird species

Rapid urbanization has a great impact on avian distribution, ecology, habitat selection, and behavior. Recent avian studies indicated that individuals remain consistent in their behavioral responses to human disturbance across short periods of time. However, there is still little information about keeping consistent behaviors in distinct locations across different stages of the annual cycle. In this study, we aimed to test for long-term consistency in habitat selection with respect to urbanization in a migratory waterbird species, the Eurasian coot Fulica atra. For this purpose, we individually marked ca. 300 coots from four populations that varied in urbanization level and tracked their habitat preferences during the non-breeding season. We found that individuals from urban breeding populations selected habitats with a higher share of artificial areas during the non-breeding season, when compared to non-urban individuals. Also, a comparison of non-breeding sites selected by birds from our study populations with random sites showed that urban birds selected sites with higher urbanization level than resulting from random availability. Finally, we found a seasonal variation in habitat preferences in coots—individuals from all study populations selected more urbanized areas as the non-breeding season progressed. The results indicate that birds are able to remain consistent in habitat preferences not only at a large geographical scale, but also across different seasons. Marked between-population variation in habitat selection across the annual cycle may reflect personality differences of coots from urban and non-urban populations, and it stays in line with the personality-matching habitat choice hypothesis.

Identifying new sites of significance to waterbirds conservation and their habitat modification in the Yellow and Bohai Seas in China

Chinese coastal wetlands in the Yellow and Bohai Seas provide a network of breeding, stopover, and wintering sites that are critical for the survival of many migratory waterbird species. However, land use change, particularly from coastal reclamation, has caused severe population declines of waterirds. Although 19 sites, covering 1.51 million hectares, were recognized as Important Bird Areas (IBAs) prior to 2009, bird surveys since 2009 have indicated additional sites may be important, and should be included in the protection area network. In this study, we compile waterbird distribution data (post-2009) from multiple sources, including citizen science databases, published and gray literatures. Using these data while also adopting internationally recognized criteria, we delineate new sites of significance to waterbird conservation. For these newly identified sites, using remote-sensed data, we develop a habitat suitability index (HSI) to identify any change in the same site between 2000 and 2015. The study results show that of 26 sites meeting criteria for significance to waterbird conservation in Chinese coastal wetlands of the Yellow and Bohai Seas, 9 sites are included within boundaries of existing IBAs, and 17 are new identified sites; Eight threatened waterbird species are recorded in 13 of the newly identified sites; and seven threatened species or species that occurred in internationally significant numbers have not been previously documented in existing IBAs; Decreases in habitat suitability are apparent at 16 of 17 newly identified sites between 2000 and 2015, as are declines in the extent of natural habitat. To curtail future population declines of waterbirds in coastal wetlands of the Yellow and Bohai Seas, prioritized conservation of these newly identified sites is urgently required.

Focusing on rapid urbanization areas can control the rapid loss of migratory water bird habitats in China

Over 240 migratory water bird species depend on China's 18,000 km coastline as a vital stopover area. However, the rapid loss of natural wetlands has threatened this seasonal water bird migration over the last few decades. In the present study, to improve our understanding of the pattern and amount of habitat loss in key stopover areas (KSAs) and the spatial covariance between habitat loss and economic development, we conducted a spatially explicit evaluation of coastal habitat loss in KSAs and explored its relationship with social and economic dynamics along the China coast by integrating high-spatial resolution satellite imagery with an updated coastal water bird investigation data set. The remote sensing survey detected a habitat loss percentage of 19.4% in the KSAs during 2000 and 2010. Aquaculture, urbanization, and land reclamation were responsible for the most severe disturbances to coastal habitats. These results demonstrate that the losses of wetland habitats in the KSAs in Chinese coastal areas are more severe than those in other coastal areas even though more protective measures have been implemented in these areas. Risk-based analysis showed that the risk of habitat loss was greatest in undeveloped regions with rich natural wetland and large populations, thereby demonstrating the critical importance of shifting the focus of water bird conservation to these regions to ensure the conservation of migratory water birds in the East Asian–Australasian Flyway. These findings disagree with the hypothesis that more habitats are lost when the economy is more developed. Therefore, we suggest that focusing conservation decisions on areas undergoing urbanization might improve the effectiveness of conservation measures given the pressures due to various forms of wetland exploitation.

Assessing the effects of human activities on the foraging opportunities of migratory shorebirds in Austral high-latitude bays.

Human presence at intertidal areas could impact coastal biodiversity, including migratory waterbird species and the ecosystem services they provide. Assessing this impact is therefore essential to develop management measures compatible with migratory processes and associated biodiversity. Here, we assess the effects of human presence on the foraging opportunities of Hudsonian godwits (Limosa haemastica, a trans-hemispheric migratory shorebird) during their non-breeding season on Chiloé Island, southern Chile. We compared bird density and time spent foraging in two similar bays with contrasting disturbance levels: human presence (mostly seaweed harvesters accompanied by dogs) was on average 0.9±0.4 people per 10 ha in the disturbed bay, whereas it was negligible (95% days absent) in the non-disturbed bay. Although overall abundances were similar between bays, godwit density was higher in the non-disturbed bay throughout the low tide period. Both days after the start of the non-breeding season and tidal height significantly affected godwit density, with different effects in either bay. Time spent foraging was significantly higher in the non-disturbed bay (86.5±1.1%) than in the disturbed one (81.3±1.4%). As expected, godwit density significantly decreased with the number of people and accompanying dogs in the disturbed bay. Our results indicate that even a low density of people and dogs can significantly reduce the foraging opportunities of shorebirds. These constraints, coupled with additional flushing costs, may negatively affect godwits’ pre-migratory fattening. Hence, as a first step we suggest limiting human presence within bays on Chiloé to 1 person per 10 ha and banning the presence of accompanying dogs in sensitive conservation areas.

Migratory connectivity and local site fidelity in red knots on the southern Pacific coast of South America

Abstract The red knot Calidris canutus, a flagship migratory waterbird species, continues to decline within the Americas. One major unanswered question is the status and connectivity of birds spending the non‐breeding season on the southern Pacific coast of South America. Answering this question will provide a useful geographic endpoint that could enhance ongoing conservation efforts. Red knots on Chiloé Island (43°S, Chile) were studied during four consecutive non‐breeding seasons (2014–2018) using systematic counts and resightings of ringed individuals in two shallow bays with known aggregations of other shorebird species. Maximum seasonal abundances (±SD) at each bay (68.8 ± 13.4; 85.0 ± 13.2) were similar across years. However, actual abundance on Chiloé is probably higher, as other suitable habitats were not surveyed. A total of 55 resightings corresponding to 14 individuals were recorded. The majority (72%) was for birds present during consecutive seasons; there were no recorded interchanges between bays. All birds, but one in Argentina, were ringed on the Atlantic coast of the USA (mainly the Gulf of Mexico) during their spring (northward) migration. Mark–resight data reveal a strong migratory connectivity between the southern Pacific coast of South America and the Atlantic coast of North America for this small but regular population of a highly imperilled species. Data also suggest that the red knots on Chiloé might be considered a separate conservation unit (most likely subspecies rufa). Thus, there is an urgent need to conduct comprehensive studies on Chiloé Island for the conservation of the intraspecific diversity of this migratory flagship species.