Waterbird Populations Research Articles

Artificial Wetlands as Breeding Habitats for Shorebirds: A Case Study on Pied Avocets in China’s Largest Saltpan Complex

Artificial wetlands such as coastal saltpans have replaced a number of coastal natural habitats worldwide and may have accommodated specific waterbird populations in the East Asian–Australasian Flyway (EAAF). The role of saltpans in the EAAF as foraging grounds for shorebirds is widely recognized, although their role as breeding grounds for waterbirds is very limited and contradictory. The Nanpu saltpans in northern Bohai Bay, China, are one of the largest saltpan complexes in the world. In this study, we monitored the nesting success (852 nests) of pied avocets (Recurvirostra avosetta) during three breeding seasons (2015, 2016, and 2018) in the Nanpu saltpans. The nest daily survival rate (DSR) was 0.970; hence, nest survival over the 27 exposure days was 44%. The apparent nest success was 51%. Surprisingly, 55% of nests failed during the laying period. Flooding and nest abandonment were the main causes of nest failure during both the laying and incubation periods. We found a strong positive relationship between the DSR and nest age, with nests that approached hatching having a greater probability of survival than freshly started nests. We also found a strong negative relationship between the DSR and precipitation, with the highest DSR observed for nests that experienced no precipitation. The DSR decreased over the course of the 71-days nesting season and followed a linear trend. The DSR was also density dependent and decreased slightly when nests were denser. A literature review showed that nest survival in the Nanpu saltpans was average compared with that of other studies and that nest success in artificial wetlands was significantly higher than that in natural wetlands or both habitats. Nevertheless, nest success decreased with the study date, suggesting that that breeding conditions for the pied avocet are worsening with time. The loss of saltpans could negatively affect the population of avocets and other ground-nesting waterbird species; therefore, conservation actions and research efforts should be strengthened to understand and conserve these functional wetlands for waterbirds.

Diet and Life-History Traits of Savannah Dwelling Waterbirds in Southern Africa: Implications for Their Conservation Status

This study evaluates the relative contribution of reproduction-based life history traits and diet to the population trends in waterbirds from southern Africa. Life history traits (clutch size, incubation period, fledging time, body mass and generation length), diet (prey weight, body lengths and number of taxa represented in its diet (NTD)) and conservation status (declining/not declining) of 163 waterbird species were reviewed. An index of diet generalism was created based on NTD. Cluster analysis was applied on life history traits to define groups of waterbirds. Binomial regressions were used to test if population trends were different across cluster groups and diet variables. Four clusters of waterbirds were defined, with most waterfowl clustering together. Species that feed on small and large prey had higher probabilities of declining (0.17 and 0.26, respectively) compared to those feeding on medium-sized prey (0.08). Amphibians, coleopterans, crustacea, molluscs and tunicates were used by species in all clusters, and the risk of waterbird populations declining further are high given the current dwindling of the prey base. The large proportions of declining species (61%) in waterbirds, which have constrained habitats, calls for continued efforts to mitigate disturbances to wetlands.

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.

The estimation of the coastal fisheries resources quantity based on waterbirds in the Ujung Pangkah Region, Gresik Regency, East Java

Waterbirds are a group of birds that have a high dependence on natural and artificial aquatic habitats. Its existence indicates the availability of sufficient feed at that location. This is related to bird habitat preference, which always makes feed one of the basic things to fulfill their daily needs. The Ujung Pangkah area is an estuary habitat occupied by waterbirds, both resident and migratory birds. Therefore this area provides sufficient feedstock for the existing waterbirds. Most of the aquatic bird feed is aquatic animals that live in aquatic ecosystems. This research is expected to provide a general description of the relationship between waterbirds and the number of fishery resources. The research was conducted in November 2019 in six locations in the Ujung Pangkah Region, Gresik Regency, East Java. The study results found that the waterbird population’shighest density of the was found in Kalianyar with a density of 3,878.98 ind/ha. In line with this, Kalianyar has become a high location for stocks of fishery resources. A total of 8,880,000 ind/ha benthic and 29.30 ind/ha necton were found in this location.

Wetland restoration in the East Dongting Lake effectively increased waterbird diversity by improving habitat quality

Wetland restoration is an effective way to recover degraded wetlands worldwide. The Dongting Lake wetland, an important wintering habitat for waterbirds, has suffered considerable degradation due to climate change and human disturbance during the last two decades; however, wetland restoration projects have now been implemented to improve waterbird diversity in the Dongting Lake. Based on annual waterbird and habitat survey data (2012/2013–2019/2020), we aimed to compare the differences in habitat variables (e.g., sedge [Carex spp.] meadow area, mudflat area, water area, and the normalized difference vegetation index of the sedge [Carex spp.] meadow) between the restored and unrestored wetlands to confirm whether wetland restorations could improve habitat quality. We also evaluated whether wetland restoration could effectively improve waterbird diversity by comparing the differences in waterbird populations at the community, foraging guild, feeding habitat guild, and species levels in the restored and unrestored wetlands. The results indicated that the restored wetland could provide more diverse and suitable habitats than the unrestored ones, particularly in terms of a sufficient variety of water habitats of different depths for waterbirds. The restored wetland was able to support substantial and diverse waterbird populations during the winter season. Specifically, compared to the unrestored wetlands, the restored wetland generally had higher species richness, individual density, and Shannon–Wiener diversity index at the community level; higher densities or proportions of different foraging guilds (tuber feeders, herbivores, fish eaters, insectivores, and omnivores, except herbivores geese), and of different feeding habitat guilds (G [0–10 cm], G (20–50 cm), G (20–70 cm), and G (>70 cm) guilds); and higher densities or proportions of the target species (except the lesser white-fronted goose and bean goose) at the species level. The larger waterbird populations in the restored wetland might be closely related to suitable crucial habitats, as indicated by positive correlation between their abundance and suitable habitat areas. Creating diverse suitable habitats for waterbirds, according to their habitat requirements, should be the first consideration in future wetland restorations. These findings provide a basis for wetland restoration and protection of wintering waterbird diversity in the Dongting Lake as well as in the middle and lower reaches of the Yangtze River floodplain.

Unravelling diet composition and niche segregation of colonial waterbirds in a Mediterranean wetland using stable isotopes

Rice fields and waterbirds are an example of a synergy that can occur between agriculture and conservation. This connection is especially relevant during the farming period, when nesting waterbirds need to obtain resources to cover their energy requirements and those of their chicks in rice fields. However, new farming techniques may potentially put fulfilling this role at risk. Studies on how species use rice fields to feed during this critical period are essential to understand waterbird population dynamics and to optimize conservation measures. At present, several species of colonial birds in l’Albufera de València (Spain) that depend on trophic resources available in rice fields have decling populations and decreases in productivity. We therefore assessed trophic niche segregation in the diet of chicks of a waterbird community composed of seven species through stable isotope analyses of carbon (δ13C) and nitrogen (δ15N) obtained from chick blood and tissue samples of potential prey. According to trophic niche widths, chicks of Black‐headed GullChroicocephalus ridibundusand Gull‐billed TernGelochelidon niloticashowed a similar diet, although Gull‐billed Tern had a major trophic specialization. The Western Cattle EgretBubulcus ibisfed its chicks in a wider range of different habitats, with organisms located at the base of the food chain and with a greater importance of terrestrial prey than other species. Conversely, the Glossy IbisPlegadis falcinellushad a more differentiated diet, mostly in freshwater habitats and mainly consuming odonates. Grey HeronArdea cinerea, Little EgretEgretta garzettaand Squacco HeronArdeola ralloidesshowed overlap between their niches, largely explained by the presence and abundance of cyprinid fish and odonates in their diets. Our results suggest a less important role than expected of Red‐swamp CrayfishProcambarus clarkii, and a more important role of odonates despite being a less energy‐rich prey. In conclusion, the diet of generalistic species of waterbirds in this study suggests that their trophic niches can overlap when relative prey abundance is high.

中国大陆沿海水鸟栖息地保护优先区及空缺分析

中国大陆沿海湿地是东亚-澳大利西亚候鸟迁徙的重要停歇地，自然湿地丧失与退化已经严重威胁到水鸟生物多样性的稳定性，急需开展物种及其栖息地的保护工作。识别中国大陆沿海水鸟保护优先区，针对保护优先区进行保护优先等级划分，确定目前尚存的保护空缺，是针对性开展水鸟栖息地保护的前提。以中国大陆沿海11省、自治区、直辖市沿岸湿地为研究区，整合鸟类网站、水鸟调查报告和文献中的水鸟调查数据，采用热点分析方法，确定水鸟保护优先区，将每个地块上满足水鸟保护优先区识别标准的物种数量占所有地块中满足标准的物种数量最大值的比例划分成0.5 ≤ P_i ≤ 1、0.25 ≤ P_i < 0.5、0 < P_i < 0.25三个区间，确定对应的I类、II类和III类水鸟保护优先区保护优先等级；结合国家自然保护地名录，确定水鸟保护优先区保护空缺。结果显示：共有65块中国大陆沿海水鸟保护优先区，记录到满足热点分析标准的水鸟物种共76种，其中受胁物种18种。水鸟保护优先区保护优先等级属于I、II、III类的分别有8块、10块、47块，且水鸟保护优先区保护优先等级属于I、II类的地块集中分布在上海以北的区域，水鸟保护优先区保护优先等级属于III类的地块主要分布在上海以南的区域。38块水鸟保护优先区存在保护空缺，占总数的58.46%，这些保护空缺地中保护优先等级属于I类和II类的地块共6块，建议针对这些地块单独建立保护机构或纳入现有周边的保护体系中。;Coastal wetlands in mainland China are home to rich fishery resources, mangroves and seagrass beds. They are recognized as key part of global biodiversity, providing natural eco-safety barrier for the development of economically developed coastal regions in China. They are not only known as precious natural resources, but also key components of a biotic community of mountains, rivers, forests, cropland, lakes and grasslands for their important ecological functions and values. These wetlands provide important stopover sites for migratory waterbirds along the East Asian-Australasian Flyway (EAAF), supporting millions of migratory waterbirds of international importance along the EAAF. Since 1960, large areas of natural landscapes in mainland China's coastal zones have lost as a result of rapid economic development activities, such as over-exploitation of natural resources and land reclamation for construction and farmland. These activities have led to a dramatic decline in waterbird populations in the area, and the loss and degradation of natural wetlands have threatened the stability of species and population of waterbirds. For this reason, it is necessary to protect waterbirds species and their habitats. Identifying conservation priority sites, conservation priority levels and gaps for the migratory waterbirds are important preconditions for targeted habitat conservation. Integrated survey data were derived from birding websites, survey reports of waterbirds and published literature along the 11 provinces/municipalities in China. Then we used hot-spot analysis to identify conservation priority sites of the waterbirds. We also calculated the proportion of the species number of conservation gap sites to the maximum species number, and divided these proportions into three conservation priority levels (0.5 ≤ P_i ≤ 1, I; 0.25 ≤ P_i < 0.5, II; and 0 < P_i < 0.25, III). Based on the list of national natural protected areas, we defined the conservation gap of waterbirds. The results showed 65 conservation priority sites were identified along coastal wetlands in mainland China, and 76 species (including 18 threatened species) meeting the criterion of hot-spot analysis were recorded in these sites. The conservation priority levels of these sites belong to Levels I, II and III, which had 8 sites, 10 sites and 47 sites, respectively. The sites with conservation priority levels of I and II are mainly distributed in the north of Shanghai, while the sites with conservation priority Level III mainly occur in the south of Shanghai. 38 sites are yet to be put under protection, accounting for 58.46 percent of the total number of conservation priority sites, in which six sites belong to the conservation priority levels of I and II. To address this problem, we recommend that new protected areas should be established for the conservation gap sites with the conservation priority levels I and II, and be incorporated into the existing network of protected areas.

Multifaceted local action for the conservation of the transboundary Prespa lakes Ramsar sites in the Balkans

We provide a short overview of the bottom-up, non-governmental organisation (NGO)-driven conservation efforts that go a long way towards implementing the Ramsar Convention on the ground in the Prespa basin in the Balkans. Encompassing two lakes, the transboundary Prespa basin is covered by three Ramsar sites. The lakes host significant endemism and internationally important breeding and wintering waterbirds. For over 30 years, the Society for the Protection of Prespa (SPP), a locally based NGO representing an international constituency, has successfully used the obligations, goals and objectives laid out by the Ramsar Convention. The SPP has led broader alliances, implementing and coordinating conservation action, initially on the Greek side and later at basin level, through an integrated ecosystem approach, multiparticipatory decision-making processes and transboundary collaboration. It has achieved substantial benefits for waterbird populations, especially pelicans, engaged in community-based resource management approaches and drawn support, mainly from international donors, to achieve progress in the wise use of the wetland. The established decision-making mechanisms in Greek Prespa, the long-term monitoring data on the wetland ecosystem and the operation of transboundary collaboration networks are also expected to contribute towards addressing ongoing challenges, such as eutrophication and adaptation to climate change.

Generalized estimation of nutrient loading of waterbirds on inland aquatic ecosystems

Estimating the nutrient loading of aquatic bird is complicated because it is fundamentally dependent on several biological, environmental and methodological factors. The new Boros's generalized method is relatively easy to use based on the conventional bird counting and implemented excrement (faecal) analyses by integrated daily net rates data (g/day/ind.). According to the Boros's generalized method, the carbon (C), nitrogen (N) and phosphorus (P) loading of waterbirds on aquatic ecosystems can be estimated by determining the abundance of waterbird populations and the nutrient content (C, N, P) of their excrement. Weekly total loading of waterbirds = Σ species (A × E × RTF × D), where: A (ind./m2): the daily mean of abundance of waterbird species for each month, E (g/day/ind.): the daily net rate of C, N, P in the excrement of each species, RTF: the daily residency time factor (hours spent on soda pans/24 h) of each species in the target habitat, D (n days): the number of days of each month.•Waterbirds can cause extreme guanotrophication (max. 2500 mg P/m2/y) in waters.•The nutrient loading of waterbirds can be estimated by abundance of waterbirds.•Boros's method estimates the carbon, nitrogen and phosphorus loading of waterbirds.

Study on the effect of habitat function change on waterbird diversity and guilds in Yancheng coastal wetlands based on structure–function coupling

In recent years, due to human activities and global climate change, the number and area of waterbird habitats in Yancheng coastal wetlands, a newly established world natural heritage site, have been shrinking, the function of the waterbird habitats has been degraded to varying degrees, and the safety of waterbird populations and habitats has been threatened. Therefore, in this study, waterbird habitat functions at the regional scale were assessed by using spatial principal component analysis (SPCA). According to the load matrix of principal components and the Redundancy analysis (RDA) method, the driving force of habitat function change and the mechanisms of their effects on waterbird guilds and diversity were revealed. The results showed that the areas of the highest and high habitat function grades continued to decline from 1987 to 2019, and the areas of the lowest and low grades of habitat function continued to increase. The overall habitat functions in the waterbird distribution areas were high, but the functional grades within different habitat sites were obviously decreasing. The main driving factors affecting habitat function change in Yancheng coastal wetlands from 1987 to 2019 were habitat types, habitat area, habitat diversity, habitat fragmentation, number of residential areas and reclamation intensity. The effects of these driving factors on the population diversity and distribution of waterbird guilds were different. Finally, countermeasures and suggestions for the functional maintenance and key node restoration of waterbird habitats in Yancheng coastal wetlands were proposed.

Effectiveness of the European Natura 2000 network to sustain a specialist wintering waterbird population in the face of climate change

Analysis of coordinated Greater Scaup (Aythya marila) count data from the last 30 years showed a 38.1% decrease in wintering numbers in North-West Europe, from 309,000 during 1988–1991 to c.192,300 individuals during 2015–2018. Annual trends in wintering numbers differed throughout the range. Numbers decreased in the UK, Ireland, and in the Netherlands, while numbers were stable in Denmark. Germany, Poland, Sweden, and Estonia showed increasing numbers, suggesting a shift in the distribution of the species within its wintering grounds towards the east and north. Higher temperatures in northern and eastern areas were correlated with the range shift of the wintering distribution. Deaths from bycatch drowning of Scaup in fishing gear have significantly decreased in recent decades in the Netherlands, where currently the greatest threat is considered the deterioration of food resources. The increasing concentration of wintering Scaup in coastal Poland and Germany (where lack of effective implementation of conservation measures fail to protect the species from the impacts of bycatch and declining food quality) pose major threats to the entire population.

Structure of waterbird assemblages in fragmented coastal wetlands of Northeastern Algeria

This study was carried out from 2007-2017 at the ecological complex of the Jijel wetlands in the north-east of Algeria. Censuses were conducted during the twelve months of each year to study variation in richness and abundance of waterbird populations for each season. We used distance sampling (point count and transect methods). A total of sixty species (eleven orders and sixteen families) were recorded. The Anatidae and Scolopacidae families were the most numerous with thirteen species. The common coot (Fulica atra), and the Mallard (Anas platyrhynchos) were the most abundant and frequent species each year. About 70 % of the species recorded occur as migrants, passing between the western Palearctic and their winter quarters in North Africa. Phenologically, we found 15 % were breeders, and from the point of view conservation status, 56 % were rare, 40 % were protected by Algerian regulations and 8 % were threatened species listed in the Red List of the International Union for Conservation of Nature (IUCN). Our results of ornithological monitoring in the wetlands in Algeria show that action is needed to address the consequences between birds, human activities, and climate change.

Structure of waterbird assemblages in fragmented coastal wetlands of Northeastern Algeria

This study was carried out from 2007-2017 at the ecological complex of the Jijel wetlands in the north-east of Algeria. Censuses were conducted during the twelve months of each year to study variation in richness and abundance of waterbird populations for each season. We used distance sampling (point count and transect methods). A total of sixty species (eleven orders and sixteen families) were recorded. The Anatidae and Scolopacidae families were the most numerous with thirteen species. The common coot (Fulica atra), and the Mallard (Anas platyrhynchos) were the most abundant and frequent species each year. About 70 % of the species recorded occur as migrants, passing between the western Palearctic and their winter quarters in North Africa. Phenologically, we found 15 % were breeders, and from the point of view conservation status, 56 % were rare, 40 % were protected by Algerian regulations and 8 % were threatened species listed in the Red List of the International Union for Conservation of Nature (IUCN). Our results of ornithological monitoring in the wetlands in Algeria show that action is needed to address the consequences between birds, human activities, and climate change. Data published through GBIF (Doi:10.15470/oud0fp)

Predictors of Gull-billed tern (Gelochelidon nilotica) nest survival in artificial coastal saltpans, Bohai Bay, China.

BackgroundCoastal saltpans are a common supratidal human-modified wetland habitat found within many coastal landscape mosaics. Commercial salt production and aquaculture practices often result in the creation of exposed coastal substrates that could provide suitable breeding habitat for waterbird populations; however, few studies have quantified waterbird breeding success in these artificial wetlands.MethodsHere we examine the nesting behavior of the Gull-billed tern (Gelochelidon nilotica) breeding in the Nanpu coastal saltpans of Bohai Bay, Yellow Sea, China over three consecutive nesting seasons (2017–2019) by using nest survival model in Program MARK.ResultsThe results revealed that nest survival of Gull-billed terns in coastal saltpans (0.697) was higher than previously published estimates from other regions, with an estimated daily survival rate (DSR) of 0.982 ± 0.001 (±95% CI). High nest survival was mainly attributed to low levels of human disturbances and low predation rates, while exposure to strong winds, flooding and silting were the main factors causing nest failure. Model-averaged estimates revealed that eggs laid in nests located on ‘habitat islands’ with feather or clam shell substrates were most likely to hatch. Initiation date, nest age, clutch size and quadratic effects of nearest-neighbor distance, nearest distance to road and nearest distance to water were all significant predictors of nest success, but the nest survival declined overall from 2017 to 2019 due to the degradation and loss of breeding habitat anthropogenically caused by rising water levels.DiscussionCoastal saltpans represent an alternative breeding habitat for the Gull-billed tern populations in Bohai Bay, but conservation management should prioritize flood prevention to improve the extent and quality of breeding habitat, concurrent with efforts to create further ‘habitat islands’ with suitable nesting substrate.

Priority sites and conservation gaps of wintering waterbirds in the Yangtze River floodplain

The Yangtze River floodplain is critical for migratory waterbirds along the East Asian-Australasian Flyway (EAAF). Greater awareness of its global importance is urgently needed to ensure waterbird populations remain in favourable conservation status, as well as the enhancement of wider wetland biodiversity within this region. The designation of protected wetland areas and building a green ecological corridor in the Yangtze floodplain is now becoming a critical issue of interest to the Chinese government. Priority sites in this area were identified based on the criteria used to identify sites that qualify as Wetlands of International Importance (Ramsar Sites) and Important Bird and Biodiversity Areas (IBAs) by using multi-source data. The results show that 140 of the sites surveyed are priority sites. The Importance Index (/) for the whole floodplain decreased slightly from 2001–2005 and an unbalanced distribution pattern is evident with Jiangxi and Hunan provinces significantly higher than the other provinces in the floodplain. Although more than 60% of the priority sites are currently located outside protected areas, the average Conservation Effectiveness Index (C) of the whole floodplain is 75.6%, which suggests the coverage of protected areas for most wintering waterbird population is reasonable. Conservation of the Yangtze River floodplain needs to be further strengthened due to declining waterbird abundances and the mismatch between the distribution of protected areas and their importance for wintering waterbirds. A comprehensive system for priority site identification and protection and scientific review is needed. Multi-sourced data from regular, systematic and coordinated monitoring of waterbird distribution and abundance across the EAAF, as well as national scale citizen science programmes are also critically important.

Influence of land use change on the waterbird community of Sihwa Lake, Republic of Korea

BackgroundLand use and development alter mudflat and wetland habitat availability, although mudflats and wetlands provide important stopover habitats for shorebirds during the spring and autumn migrations and support communities of ducks and geese during the winter months in the Republic of Korea. This study investigated land use changes around Sihwa Lake (Republic of Korea) and evaluated the effect of these changes on waterbird community characteristics.MethodsWe conducted a land-use-change analysis at the medium-resolution level using land cover maps for 2001, 2007, 2009, and 2014. Also, a tidal stream survey was conducted in Sihwa Lake and the surrounding reclaimed mudflats every season for 10 years (2003–2012) to identify the seasonal and interannual variations in waterbird species composition. To determine the total annual waterbird species and population counts, species diversity index, and interspecies variations, a TRIM (trends and indices for monitoring data) analysis was used.ResultsWetland area decreased more than 10% while agricultural land, barren land, and grassland area increased more than 10% due to continuous reclamation activities around Sihwa Lake. Barren land later turned into agricultural land or other land use. Sixty-three species and 566,623 individuals were recorded. The number of species, population size, and species diversity index by year and by species showed decreasing trends that were more marked in spring and summer. Furthermore, seasonal and annual variations in waterbird species composition showed decreasing trends in dabbling ducks, herons, grebes, and shorebirds but diving ducks displayed increasing trends. In particular, shorebirds were reduced to a greater extent than other waterbird species because of the reduction and simplification of the intertidal zone, and shallow waters caused by reclamation and road construction.ConclusionsIncreased development and construction around Sihwa Lake has altered migratory shorebird populations with a general decline in species diversity and population size. The greatest decline was observed in wading birds, while diving duck populations showed increasing trends.

Ecology of Avian Settlements in Lake Tonga (Northern Algeria)

Lake Tonga is an integral reserve within the El-Kala National Park, Biosphere Reserve and Ramsar site. This study consists in determining the diversity and phenology status of waterbirds in this reserve over an entire annual cycle (2017–2018). The census was carried out from fixed observation points. Of the 35 species recorded, wintering birds dominate with 12 species (34 %), followed by breeding sedentary species with 11 species (32 %). The breeding water bird populations are dominated by the common coot Fulica atra, (with a maximum of 6,033 birds) followed by the Anatidae, Herons and Grebes. Lake Tonga is a breeding area for several avian species and a recruitment site for a multitude species bird during the wintering period. Three Anatidae nest at Lake Tonga: the white-headed duck&nbsp;Oxyura leucocephala, the ferruginous duck&nbsp;Aythya nyroca and the mallard Anas platyrhynchos.

Drivers of a habitat shift by critically endangered Siberian cranes: Evidence from long-term data.

Many waterbird populations have become increasingly dependent on agricultural habitats for feeding. While habitat destruction has been proposed as a key reason forcing waterbirds to move from natural habitats to agricultural habitats, few have used long‐term data to test this hypothesis. The Siberian crane (Leucogeranus leucogeranus) is an IUCN Critically Endangered species. About 98% of its global population winters at Poyang Lake, China. Recently, many cranes shifted from feeding in natural wetlands to agricultural habitats. Here, we integrate bird surveys, Vallisneria tuber (the traditional food of cranes in natural wetlands) surveys, water level data, and remotely sensed images from 1999 to 2016 to explore the drivers of this habitat shift. Changes in Siberian crane numbers in natural wetlands and agricultural fields indicated that the habitat shift occurred in the winters of 2015–2016. Analyses using generalized linear mixed models suggested that crane numbers in natural wetlands were positively related to tuber density and the interaction between dry season (October–March) water level and tuber density. The changes in tuber density and dry season water level in 2015–2016 indicated that tuber disappearance may have been the primary driver of the habitat shift, with a smaller effect of high water level. Submerged plants at Poyang Lake have degraded seriously in the past two decades. The plant degradation at Shahu Lake, a sublake of Poyang Lake, may have been caused by high spring water, high winter temperature, and low summer temperature. However, the drivers of tuber disappearance at Poyang Lake may not be restricted to these variables. Because Poyang Lake is an important refuge for many waterbirds in the Yangtze River floodplain, it is urgent to take effective measures to restore its submerged plants and ecosystem health. Agricultural fields can be important refuges for Siberian cranes, mitigating the negative impacts of wetland deterioration.

Estudo quantitativo temporal sobre a contaminação de aves aquáticas por metais

Elementos potencialmente tóxicos podem ser considerados graves contaminantes ambientais, por não se degradarem e terem efeito acumulativo no meio ambiente e no organismo de diversas espécies. Considerando que a contaminação por metais pode estar associada ao declínio de aves aquáticas, o objetivo deste trabalho foi realizar uma análise quantitativa temporal, por meio de uma abordagem cienciométrica sobre a contaminação e possível declínio de aves aquáticas que habitam áreas potencialmente contaminadas por metais. Foram encontradas, 239 publicações indexadas nas duas bases de dados analisadas, sendo 218 publicações na base de dados da Web of Science, com uma representatividade de (91,21%) e 21 publicações (8,79%) na base de dados Scopus. Os trabalhos analisados estudaram 25 famílias e 66 espécies de aves que tiveram ao menos um órgão/tecido/estrutura (fígado, fezes, bolo estomacal, sangue, pulmão, pena coração encéfalo, ossos, unha, tecido muscular, ovos) contaminado por pelo menos um dos 18metais encontradosnos artigos analisados (Hg,Pb,Zn,Cu,Cd,Fe,Mg,Ca,Mn,Sr,As,Ni,Sc,Al,Ag,Co,Cr)e MeHg que é a forma orgânica do Hg. Os resultados das pesquisas analisadas indicaram que os metais estudados, podem comprometer a sobrevivência, capacidade de forrageamento das aves em seu ambiente natural, prejudicando também o desenvolvimento morfológico, o que poderia diminuir a possibilidade de sucesso reprodutivo, e, portanto, contribuir para o declínio das populações de aves aquáticas ao redor do mundo.