Coastal wetlands in Lianyungang, Jiangsu Province, China: probably the most important site globally for the Asian Dowitcher (Limnodromus semipalmatus)

Abstract

Background Despite an increasing number of surveys and a growing interest in birdwatching, the population and distribution of Asian Dowitcher (Limnodromus semipalmatus), a species endemic to the East Asian–Australasian and Central Asian Flyways, remains poorly understood, and published information about the species is largely outdated. In boreal spring 2019, over 22,432 Asian Dowitchers were recorded in a coastal wetland at Lianyungang, Jiangsu Province, China, constituting 97.5% of its estimated global population. Methods In 2019 and 2020, we conducted field surveys at Lianyungang to determine the numbers of Asian Dowitchers using the area during both southward and northward migrations. We also assessed the distribution and abundance of Asian Dowitchers elsewhere along the China coast by searching literature and consulting expert opinion. Results The coastal wetlands of Lianyungang are the most important stopover site for Asian Dowitchers during both northward and southward migrations; they supported over 90% of the estimated global population during northward migration in two consecutive years (May 2019 and 2020). This area also supported at least 15.83% and 28.42% (or 30.74% and 53.51% using modelled estimates) of the global population during southward migration in 2019 and 2020 respectively. Coastal wetlands in the west and north of Bohai Bay also have been important stopover sites for the species since the 1990s. Although comprehensive, long-term monitoring data are lacking, available evidence suggests that the population of the species may have declined. Conclusions The high concentration of Asian Dowitchers at Lianyungang during migration means the species is highly susceptible to human disturbances and natural stochastic events. The coastal wetlands of Lianyungang should be protected and potentially qualify for inclusion in China’s forthcoming nomination for World Heritage listing of Migratory Bird Sanctuaries along the Coast of Yellow Sea-Bohai Gulf of China (Phase II) in 2023. Additional research is needed to understand Asian Dowitchers’ distribution and ecology, as well as why such a high proportion of their population rely on the Lianyungang coast.

Seabirds in China in the face of industrial activities and oil spill: lessons learnt from Bohai Bay

“…For instance, the Lianyungang coast is one of the most important stopover sites for Asian Dowitchers. Roughly over 90% of Asian Dowitchers were recorded on a single day in two consecutive springs [6]. The government has been paying attention to some of the sites, for currently two areas in coastal China are listed as natural World Heritage sites(UNESCO) for their significance as migratory bird sanctuaries.…”

“…In 2022, China's oil consumption is reported at 14,225,000 Barrels/Day, making it the second biggest oil consumer by country [5]. From year 1990-2010, about 22,035 tons of oil were lost to China's water as results of tanker incidents [6]. In this situation, chronic oil pollution could have long been undermining thousands of seabirds that either breed or migrate by China's coastlines and the wellbeing of both terrestrial and marine ecosystems.…”

“…In this situation, chronic oil pollution could have long been undermining thousands of seabirds that either breed or migrate by China's coastlines and the wellbeing of both terrestrial and marine ecosystems. Globally, Oil spills have killed millions of seabirds, while an estimated one million tons of oil now enter the oceans each year: 45% from the land; 35% from marine transportation; 10% from oil tanker spills; and 5% from natural seeps [6]. Birds that interact with oil spill on a regular basis can suffer from sublethal to lethal consequences, which include anemia, decreased immune response, and organ damage that could further lead to neurological system and respiratory system damage as ingestion occurs while preening [4].…”

“…Figure3. Oil spill occurrences and correspondence with time(month) [6]. The level of oil spill responding stockpile owned by Bohai Bay does not corresponds to its level of oil spill risk and its level of seabird diversity.…”

Autumn Migration Strategy of Asian Dowitchers (Limnodromus semipalmatus) from Eastern Mongolia

“…world, the highest number recorded in the East Asia-Australian migration route (Yang et al, 2019). However, it is unclear whether the high number recorded in 2019 was an anomaly due to climate and natural factors or whether it is a regular gathering in Lianyungang (Yang et al, 2019;.…”