scholarly journals Organising a juvenile ratio monitoring programme for 10 key waterbird species in the Yangtze River floodplain: analysis and proposals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuxi Wang ◽  
Iderbat Damba ◽  
Qingshan Zhao ◽  
Yanbo Xie ◽  
Xueqing Deng ◽  
...  
Keyword(s):  
Population Size ◽  
Age Structure ◽  
Yangtze River ◽  
Monitoring Programme ◽  
Optimal Time ◽  
The Yangtze River ◽  
Important Indicator ◽  
Factors Affecting ◽  
River Floodplain ◽  
Waterbird Species

Abstract Background In the face of continued degradation and loss of wetlands in the Yangtze River floodplain (YRF), there is an urgent need to monitor the abundance and distribution of wintering waterbirds. To understand fully observed annual changes, we need to monitor demographic rates to understand factors affecting global population size. Annual reproduction success contributes to dynamic changes in population size and age structure, so an assessment of the juvenile ratio (i.e. first winter birds as a proportion of total number aged) of overwintering waterbirds can be an important indicator of the reproductive success in the preceding breeding season. Methods During 2016–2019, we sampled juvenile ratios among 10 key waterbird species from the wetlands in the YRF. Based on these data, we here attempt to establish a simple, efficient, focused and reliable juvenile ratio monitoring scheme, to assess consistently and accurately relative annual breeding success and its contribution to the age structure among these waterbird species. Results We compared juvenile ratio data collected throughout the winter and found that the optimal time for undertaking these samples was in the early stages of arrival for migratory waterbirds reaching their wintering area (early to mid-December). We recommend counting consistently at key points (i.e. those where > 1% biogeographical flyway population were counted) at sites of major flyway importance (Poyang Lake, East Dongting Lake, Shengjin Lake, Caizi Lake, Longgan Lake and Chen Lake). Based on this, the error rate of the programme (155 planned points, the count of 10 waterbird species is 826–8955) is less than 5%. Conclusions We established a juvenile ratio monitoring programme for 10 key waterbird species in the wetlands of the YRF, and discuss the feasibility and necessity of implementing such a future programme, and how to use these data in our monitoring and understanding of the population dynamics of these waterbird populations.

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

2020 ◽  
Vol 30 (10) ◽  
pp. 1617-1632
Author(s):  
Shaoxia Xia ◽  
Xiubo Yu ◽  
Jinyu Lei ◽  
Richard Hearn ◽  
Bena Smith ◽  
...  
Keyword(s):  
Yangtze River ◽  
The Yangtze River ◽  
River Floodplain

scholarly journals Multiscale effects of habitat and surrounding matrices on waterbird diversity in the Yangtze River Floodplain

2020 ◽  
Author(s):  
Boyu Gao ◽  
Peng Gong ◽  
Wenyuan Zhang ◽  
Jun Yang ◽  
Yali Si
Keyword(s):  
Yangtze River ◽  
Structural Features ◽  
Ordinary Least Squares ◽  
Habitat Connectivity ◽  
The Yangtze River ◽  
Least Squares Regression ◽  
Spatial Error ◽  
River Floodplain ◽  
Surrounding Landscape ◽  
Shape Complexity

Abstract Context With the expansion in urbanization, understanding how biodiversity responds to the altered landscape becomes a major concern. Most studies focus on habitat effects on biodiversity, yet much less attention has been paid to surrounding landscape matrices and their joint effects. Objective We investigated how habitat and landscape matrices affect waterbird diversity across scales in the Yangtze River Floodplain, a typical area with high biodiversity and severe human-wildlife conflict. Methods The compositional and structural features of the landscape were calculated at fine and coarse scales. The ordinary least squares regression model was adopted, following a test showing no significant spatial autocorrelation in the spatial lag and spatial error models, to estimate the relationship between landscape metrics and waterbird diversity. Results Well-connected grassland and shrub surrounded by isolated and regular-shaped developed area maintained higher waterbird diversity at fine scales. Regular-shaped developed area and cropland, irregular-shaped forest, and aggregated distribution of wetland and shrub positively affected waterbird diversity at coarse scales. Conclusions Habitat and landscape matrices jointly affected waterbird diversity. Regular-shaped developed area facilitated higher waterbird diversity and showed the most pronounced effect at coarse scales. The conservation efforts should not only focus on habitat quality and capacity, but also habitat connectivity and complexity when formulating development plans. We suggest planners minimize the expansion of the developed area into critical habitats and leave buffers to maintain habitat connectivity and shape complexity to reduce the disturbance to birds. Our findings provide important insights and practical measures to protect biodiversity in human-dominated landscapes.

Application of unstructured grid finite-volume coastal ocean model (FVCOM) to the Yangtze River hypoxic zone

2016 ◽  
Vol 26 (8) ◽  
pp. 2410-2418 ◽  
Author(s):  
Zhanhong Wan ◽  
Zongfu Ren ◽  
Xiaochun Wang ◽  
Honghao Zheng
Keyword(s):  
Finite Volume ◽  
Yangtze River ◽  
River Flow ◽  
Ocean Model ◽  
Trade Wind ◽  
Freshwater Flux ◽  
The Yangtze River ◽  
Content Type ◽  
Factors Affecting ◽  
Coastal Ocean Model

Purpose To observe the relations between three important factors resulting in estuarial Hypoxia phenomena of Yangtze River – wind, river flow, and stratification. The purpose of the paper is to analyze the possible reasons why hypoxia occurs in late spring and disappears in October. Design/methodology/approach To overcome the difficulty in examining the role of physical and biological factors affecting hypoxia based on measurement alone, finite-volume community ocean model (FVCOM) was introduced into the investigation. Observed freshwater flux data from Yangtze River, monthly averaged wind speed data, and other observed data were input into the model; the accuracy of which was validated with various kinds of data. The authors used the trajectories of Lagrangian particles from Yangtze River to study the regions of strong riverine influence under different wind forcing conditions and compared the simulation results with former observations. Findings Trade wind is a significant factor to influence the forming and receding of hypoxia across the Yangtze River. Originality/value Using FVCOM to investigate estuary hypoxia is more economical and effective.

scholarly journals Changes in Tundra Swan Cygnus columbianus bewickii distribution and abundance in the Yangtze River floodplain

2011 ◽  
Vol 21 (3) ◽  
pp. 260-265 ◽  
Author(s):  
PEIHAO CONG ◽  
LEI CAO ◽  
ANTHONY D. FOX ◽  
MARK BARTER ◽  
EILEEN C. REES ◽  
...  
Keyword(s):  
Water Quality ◽  
Yangtze River ◽  
Poyang Lake ◽  
Submerged Vegetation ◽  
Three Gorges ◽  
The Yangtze River ◽  
Vegetation Productivity ◽  
River Floodplain ◽  
Cygnus Columbianus ◽  
Tundra Swan

Approximately 75% of the East Asian Flyway Tundra Swan Cygnus columbianus bewickii population winters in the Yangtze River floodplain, China. Historically the species was more widely distributed throughout the floodplain but now most of the population is confined to five wetlands in Anhui Province and to Poyang Lake in Jiangxi Province, where the majority (up to 113,000 birds) occur. Within-winter counts suggest that swans congregate at Poyang Lake before dispersing to other sites later in the winter. Counts show large between-year fluctuations, but suggest declines at Shengjin and Fengsha Lakes (both in Anhui) during the last five years. Declines at Shengjin Lake are likely due to decreases in submerged vegetation (particularly tuber-producing Vallisneria, a major food item) perhaps linked to eutrophication. Range contractions throughout the floodplain may also be linked to reductions in submerged vegetation coverage elsewhere. Changes in water quality and lake hydrology post-Three Gorges Dam may have adversely affected submerged vegetation productivity. Key information needs for the effective implementation of conservation measures for Tundra Swans include: (1) annual surveys of all major wintering sites throughout each winter to establish the importance of different sites during the non-breeding period; (2) more information on swan diets at important sites; and (3) an assessment of adverse effects of water quality and lake water levels post-Three Gorges Dam on submerged vegetation productivity at Poyang Lake and other important sites.

Balancing Growth and Preservation: Protection and Management of Nanxun Historic Water Town

2013 ◽  
Vol 368-370 ◽  
pp. 411-416
Author(s):  
Shan Jin ◽  
Hai Bo Huang ◽  
Kun Liu
Keyword(s):  
Social Development ◽  
Yangtze River ◽  
The Yangtze River ◽  
Historic Sites ◽  
Environmental Pressures ◽  
Factors Affecting ◽  
New Development ◽  
Outstanding Universal Value ◽  
Protective Strategy ◽  
The Town

Today in the context of contemporary rapid economic and social development many of the Chinese historic sites are being destroyed to make a way for new development, which is resulting in the abrupt disappearance of character and identity of the unique places. Nanxun historic water town is the most representative and unique water town in South of the Yangtze River. This paper analyzes the outstanding universal value of Nanxun historic water town, addresses the factors affecting the town such as development pressures, tourism pressures, and environmental pressures. It proposes the protective strategy for water towns in South of the Yangtze River, so that it can provide the useful experience for other historic sites in China.

scholarly journals Migration routes, population status and important sites used by the globally threatened Black-faced Spoonbill (Platalea minor): a synthesis of surveys and tracking studies

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yiwen Chen ◽  
Yat-tung Yu ◽  
Fanjuan Meng ◽  
Xueqin Deng ◽  
Lei Cao ◽  
...  
Keyword(s):  
Yangtze River ◽  
Conservation Status ◽  
Far East ◽  
Satellite Tracking ◽  
Coastal Areas ◽  
Liaoning Province ◽  
Population Abundance ◽  
The Yangtze River ◽  
Term Survival ◽  
River Floodplain

Abstract Background The Black-faced Spoonbill (Platalea minor) is a globally threatened species, nesting mainly in western Korea with smaller numbers breeding in Liaoning Province, China, and Far East Russia. Recent winter field surveys to estimate the species’ population size were almost totally conducted in coastal areas, but tracking studies showed that some individuals now winter inland. To ensure its long-term survival, we need a more comprehensive assessment of the current distribution and abundance of the species. Methods We combined the most recent count data and satellite tracking information to update existing information about the population abundance and distribution of the Black-faced Spoonbill at all stages of its annual life cycle, and how these have changed during 2004–2020. Results Black-faced Spoonbills mainly breed on the west coast of the Korean peninsula, while immature birds show a wider summer distribution throughout Yellow Sea coastal areas, when a few remain on wintering sites in the south. Combined tracking results and mid-winter counts confirmed known wintering sites on the east and south coasts of China, but showed that the species also winters on wetlands in the Yangtze River floodplain and in Southeast Asia. During 2004–2020, counts of wintering birds in coastal habitats increased from 1198 to 4864, with numbers wintering on the island of Taiwan contributing most to the overall increase. Latest counts found 5222 in 2021. We also identify key wintering and stopover sites as well as their current conservation status. Conclusions This study revised the known summering and wintering ranges of the Black-faced Spoonbill and assessed the conservation status of key sites based on a combination of field survey and satellite tracking data. We recommend prioritisation of further field research to identify and survey inland wintering areas in the Yangtze River floodplain and summering areas of immature birds. More tracking of adult individuals and birds during spring migration is necessary to fill these information gaps. We also suggest establishing a Black-faced Spoonbill monitoring platform to store, share and show real-time distribution range and population abundance data.

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