Comparison of IUCN and species distribution modeling-estimated ranges of shorebirds in Coastal Mainland China

Large areas of unsuitable habitat are often included within the extent of occurrence (EOO) of species, such as the EOO defined by the IUCN (EOOiucn), because the techniques used to estimate the EOO of species often depend on topological methods that do not account for ranges of environmentally suitable habitat. Assessments of the EOO of species are important because they are used in conservation status evaluations. We generated species distribution models in MaxEnt using citizen science data for 8 shorebird species inhabiting China’s coasts from multiple open data sources along with environmental variables to estimate the EOO of these species (EOOm). We then compared EOOm and EOOiucn and assessed the conservation status of these species according to the distribution of national nature reserves. EOOm was generally smaller than EOOiucn for the 8 shorebird species. Over 80 % of the EOOm of the 8 shorebird species did not fall within any national nature reserves, revealing large conservation gaps. Some of unprotected EOOm of these species overlaps with high human footprint area, especially in the Bohai Bay and the Jiangsu–Shanghai coastal region. Our results highlight the need for strengthened conservation effort for unprotected EOOm showing little overlap with national nature reserves, especially in the Bohai Bay and Jiangsu–Shanghai coastal regions

It takes two to Tango: Plant height and nutrient level determine the diet selection of wintering geese in Poyang Lake, a Ramsar wetland

In Poyang Lake, the largest and one of the most important wintering sites in the East Asian-Australasian Flyway, Carex (Carex cinerascens Kük) meadows provide the primary food source for the wintering geese. However, due to intensified river regulation and more frequent extreme climatic events such as drought, observational evidence suggests that the synchrony of geese migration and Carex phenology could not be maintained without human interventions, imposing a great risk of food shortage during the wintering period. Consequently, the current conservation priority in this Ramsar site is shifted to wet meadow improvement to ensure optimal food quality. Understanding the food preferences of wintering geese is the key for effective wet meadow management. As the growth stage and nutrient level of food plants are the decisive factors influencing the diet selection of herbivores, in this study, we sampled the preferred food items by tracking the foraging paths of the Greater White-fronted Goose (n = 84) and Bean Goose (n = 34) to quantify the “foraging window” in terms of plant height,protein level, and energy content. Further, we established relationships between the above three variables of Carex based on in-situ measurements. The results show that the geese prefer plants with height ranging from 2.4 to 25.0 cm, with protein content from 13.9 to 25.2 %, and energy content from 1440.0 to 1813.6 KJ/100 g. While plant energy content increases with height, the height-protein level relationship is negative. The opposite growth curves signify a conservation challenge to maintain the delicate balance between the quantity and quality requirements of wintering geese. Carex meadow management, such as mowing, should focus on optimizing the timing of action to maximize energy supply while maintaining the right protein level for the long-term fitness, reproduction and survival of the birds

Suitable Habitat Dynamics of Wintering Geese in a Large Floodplain Wetland: Insights from Flood Duration

The relationship between hydrological variation and the habitat use of waterbirds in wetland complexes is a significant field of ecological research. Quantification of the relationships between wetland hydrological attributes and waterbirds distribution is critical for the success of waterbird conservation. In this study, flood duration (FD) derived from synthetic aperture radar (SAR) imagery was combined with geese GPS tracking data to quantify the optimal FD thresholds for identifying geese habitats. Based on the thresholds, we defined the suitable habitats of wintering geese and investigated the difference in the spatial distribution pattern of habitat from 2018 to 2020 in Poyang Lake, China. We also considered the role of sub-lakes in habitat protection. The results showed that the area of suitable habitats for wintering geese decreased in both dry and wet years, and the range of optimal FD threshold was wider in normal years than in both dry and wet years. The proportion of suitable habitats per unit area was greater in the sub-lakes than in the whole Poyang Lake. We concluded that FD indices extracted from SAR data are valuable for reflecting the influence of the pattern of hydrological variation on waterbird distribution and for the protection and rational use of wetland ecosystems

Conservation and restoration efforts have promoted increases in shorebird populations and the area and quality of their habitat in the Yellow River Delta, China

Conservation policies have been formulated for coastal wetlands in China, and exploration of conservation effectiveness based on waterbirds and their habitat is important for guiding conservation actions. We characterized the effects of conservation efforts on shorebird diversity, habitat area and quality using long-term remote sensing data, and shorebird survey data in the Yellow River Delta. From 1997 to 2021, habitat area, quality and population number significantly declined by 49.8% (r = −0.72, p p 2 = 0.77, p p > 0.05, slope = −0.25), quality (decreased by 10.53%, r = −0.68, p > 0.05, slope = −0.008), and population size (significantly decreased by 94.5%, r = −0.95, p p p > 0.05, slope = 0.12), quality (increased by 17.12%, r = 0.83, p > 0.05, slope = 0.01), and population size (increased by 8.34%, R2 = 0.29, p > 0.05) slightly increased. The coefficients of variation for habitat area and quality, and population size were smaller after 2012 than before 2012. These results suggest that conservation actions maintained the stability of waterbird populations and their habitat; additional actions are needed to mediate the conservation of other degraded habitats along coastal wetlands.</p

Using citizen science data to inform the relative sensitivity of waterbirds to natural versus human-dominated landscapes in China

Habitat loss is widely regarded as one of the most destructive factors threatening native biodiversity. Because migratory waterbirds include some of the most globally endangered species, information on their sensitivity to landscape would benefit their conservation. While citizen science data on waterbird species occurrence are subjected to various biases, their appropriate interpretation can provide information of benefit to species conservation. We apply a bootstrapping procedure to citizen science data to reduce sampling biases and report the relative sensitivity of waterbird species to natural versus human-dominated landscapes. Analyses are performed on 30,491 data records for 69 waterbird species referred to five functional groups observed in China between 2000 and 2018. Of these taxa, 30 species (43.5%) are significantly associated with natural landscapes, more so for cranes, geese, and ducks than for shorebirds and herons. The relationship between land association and the threat status of waterbirds is significant when the range size of species is considered as the mediator, and the higher the land association, the higher the threat status. Sensitive species significantly associated with natural landscapes are eight times more likely to be classified as National Protected Species (NPS) Classes I or II than less sensitive species significantly associated with human-dominated landscapes. We demonstrate the potential for citizen science data to assist in conservation planning in the context of landscape changes. Our methods might assist others to obtain information to help relieve species decline and extinction

Potential Habitats and Their Conservation Status for Swan Geese (<i>Anser cygnoides</i>) along the East Asian Flyway

Habitats provide essential space for migratory birds to survive and reproduce. Identifying potential habitats in annual cycle stages and their influencing factors is indispensable for conservation along the flyway. In this study, we obtained satellite tracking of eight swan geese (Anser cygnoides) wintering at Poyang Lake (28°57′4.2″, 116°21′53.36″) from 2019 to 2020. Using the Maximum Entropy species distribution model, we investigated the potential habitats distribution of the swan geese during their migration cycle. We analyzed the relative contribution of various environmental factors to habitat suitability and conservation status for each potential habitat along the flyway. Our results show that the primary wintering grounds of swan geese are located in the middle and lower reaches of the Yangtze River. Stopover sites were widely distributed, mainly in the Bohai Rim, the middle reaches of the Yellow River, and the Northeast Plain, and extended westward to Inner Mongolia and Mongolia. Breeding grounds are mainly in Inner Mongolia and eastern Mongolia, while some are scattered in Mongolia’s central and western. The contribution rates of major environmental factors are different in breeding grounds, stopover sites, and wintering grounds. Breeding grounds were influenced by slope, elevation, and temperature. Slope, human footprint index, and temperature were the main factors that affected stopover sites. Wintering grounds were determined by land use, elevation, and precipitation. The conservation status of habitats is 9.6% for breeding grounds, 9.2% for wintering grounds, and 5.3% for stopover sites. Our findings thus provide a critically international assessment of potential habitats protection for geese species on the East Asian Flyway

Potential Habitats and Their Conservation Status for Swan Geese (Anser cygnoides) along the East Asian Flyway

Habitats provide essential space for migratory birds to survive and reproduce. Identifying potential habitats in annual cycle stages and their influencing factors is indispensable for conservation along the flyway. In this study, we obtained satellite tracking of eight swan geese (Anser cygnoides) wintering at Poyang Lake (28&deg;57&prime;4.2&Prime;, 116&deg;21&prime;53.36&Prime;) from 2019 to 2020. Using the Maximum Entropy species distribution model, we investigated the potential habitats distribution of the swan geese during their migration cycle. We analyzed the relative contribution of various environmental factors to habitat suitability and conservation status for each potential habitat along the flyway. Our results show that the primary wintering grounds of swan geese are located in the middle and lower reaches of the Yangtze River. Stopover sites were widely distributed, mainly in the Bohai Rim, the middle reaches of the Yellow River, and the Northeast Plain, and extended westward to Inner Mongolia and Mongolia. Breeding grounds are mainly in Inner Mongolia and eastern Mongolia, while some are scattered in Mongolia&rsquo;s central and western. The contribution rates of major environmental factors are different in breeding grounds, stopover sites, and wintering grounds. Breeding grounds were influenced by slope, elevation, and temperature. Slope, human footprint index, and temperature were the main factors that affected stopover sites. Wintering grounds were determined by land use, elevation, and precipitation. The conservation status of habitats is 9.6% for breeding grounds, 9.2% for wintering grounds, and 5.3% for stopover sites. Our findings thus provide a critically international assessment of potential habitats protection for geese species on the East Asian Flyway

Identifying priority sites and gaps for the conservation of migratory waterbirds in China's coastal wetlands

Many waterbird species, in particularly migratory shorebirds, on the East Asian-Australasian Flyway depend on the intertidal areas of coastal China. In recent years, these habitats have suffered severe shrinkage as a result of wetland loss and degradation. Identifying critical areas for waterbirds and assessing conservation status has become an urgent priority for biological conservation. Based on the criteria used to designate Ramsar sites and East Asian-Australasian Flyway Partnership (EAAFP) Flyway Network sites, a general framework is proposed and applied to identify priority sites in China's coastal wetlands using a comprehensive waterbird survey dataset. Sites priority were evaluated by using appearance of globally threatened bird species, and bid species exceeding 1% of their global or flyway population, and population abundance. Sites priorities were ranked using an "irreplaceability index". Totally, 110 sites are proposed as priority sites. Considering the strategic importance of China's coastal wetlands for migratory waterbirds, the conservation status of China's coastal wetlands is inadequate to protect these waterbirds. Currently, 67 of the 110 priority sites lie outside protected areas. Some critical habitats for waterbirds are not included in individual protected areas, especially in Jiangsu, Zhejiang, and. Hebei provinces. Improved protection of these areas is urgently needed. However, conservation efforts in China's coastal wetlands face numerous challenges. Many important intertidal areas are increasingly threatened by ongoing and future reclamation plans. There is an urgent need to re-consider and limit the reclamation, particularly at critical sites, and put in place conservation measures to protect migratory waterbirds and their habitats. (C) 2016 Elsevier Ltd. All rights reserved

Differences of Regulative Flexibility between Hydrological Isolated and Connected Lakes in a Large Floodplain: Insight from Inundation Dynamics and Landscape Heterogeneity

The inundation areas of floodplains are crucial to wetland ecosystems, especially in supporting biodiversity. Accurately identifying the spatial and temporal patterns of inundation areas is important for understanding floodplain ecosystem processes. Here, lakes in the Yangtze River Floodplain were divided into two types according to hydrological conditions: the natural connected lakes (Dongting Lake and Poyang Lake) with natural water level fluctuations and the isolated lakes (lakes in Jianghan Plain) with stable water levels. We established a method to identify inundation areas using multi-sources remote sensing data based on the Google Earth Engine. The dynamics of inundation areas were determined, and the relative indices were calculated in common year (2017) and a drought year (2018). The differences between the connected lakes and the isolated lakes were analyzed, and impacts of hydrological fluctuations on inundation area and habitat quality were evaluated. The results show that lakes with natural hydrological fluctuations have a greater regulative flexibility, with both patch density (PD) and submerged elasticity index (SEI) values higher than that of isolated lakes. The trend of the vegetation index in the connected lakes and in the isolated lakes is also different. The mean EVI in Dongting Lake and Poyang Lake showed a U-shaped trend which is similar to the shape of the trend of PD. The trend of mean enhanced vegetation index (EVI) in the isolated lakes is the opposite and has a lower range of variation over a year. This study provides new indicators and rapid methods for habitat quality assessment in floodplains, as well as presenting scientific information useful for improving wetland management in the middle and lower Yangtze River

The effect of laser surface melting on grain refinement of phase separated Cu-Cr alloy

Grain refinement and homogenization of Cr phase were achieved by laser surface melting (LSM) method, and the properties of Cu-Cr alloy were significantly improved. In this study, LSM of Cu-50Cr alloy (wt.%) was conducted with a high power density (10(6) -10(7) W/cm(2)) laser beam, the microstructure and the properties of melt layer were investigated. The size of Cr phase was effectively refined from hundreds of micron scale to several micron scale, and the average size of Cr particles decreased to a few hundred nanometers. High cooling rate effectively inhibited coarsening effect on the Cr particles during liquid phase separation. Spherical Cr particles were dispersed in the melt layer with a thickness of 165 +/- 20 mu m. Microhardness was obviously enhanced and the maximum hardness was 232HV, which was 2.8 times that of the substrate. Arc duration of the LSM treated contacts increased up to 18%. The withstanding voltage of the fixed and the moving contact increased to 28.7% and 35.4%, respectively. The results show that LSM is an effective method to refine the microstructure of Cu-Cr alloy, and it is a promising modification method for electrical Cu-Cr vacuum contacts