Declines in Common and Migratory Breeding Landbird Species in South Korea Over the Past Two Decades

Abstract

Population declines in terrestrial bird species have been reported across temperate regions in the world and are attributed to habitat loss, climate change, or other direct mortality sources. North American and European studies indicate that long-distance migrants, common species, and species associated with grasslands and agricultural lands are declining at the greatest rates. However, data from East Asia on avian population trends and associated drivers are extremely sparse. We modeled changes in occupancy of 52 common breeding landbird species in South Korea between 1997–2005 and 2013–2019. Thirty-eight percent of the species showed evidence of declines, and seven of these were declining severely (46–95%). Occupancy of Black-capped Kingfisher (Halcyon pileata) populations have dropped the most precipitously over the study period. Among declining species, long-distance migrants (9/20) and common species (14/20) showed more rapid declines than other groups. Declines of five species were associated with climate change, and two species appeared to be affected by land-cover change. However, causes of change in occupancy of other species (46/52) remains cryptic. Based on our results, we suggest an immediate re-evaluation of species’ conservation status and legal protection levels for seven severely declining species in South Korea, and a dedicated survey design and analysis effort for the continued monitoring landbird populations. Because many species exhibiting declines migrate from beyond national boundaries, international collaborations will be required to better quantify population trends across the full annual cycle, and to understand mechanisms for these declines.

Comparative single‐cell transcriptomic analysis reveals differences in signaling pathways in gonadal primordial germ cells between chicken ( Gallus gallus ) and zebra finch ( Taeniopygia guttata )

“…Biodiversity is essential for ecosystems to function well and provides crucial services, impacting the economy, human health, and quality of life 1 . However, particularly in birds, biodiversity is threatened worldwide due to habitat loss, degradation, and climate change 2 . In the last 50 000 years, 10%–20% of bird species have become extinct and many more are threatened, indicating the urgency of genetic conservation 3 .…”

“…1 However, particularly in birds, biodiversity is threatened worldwide due to habitat loss, degradation, and climate change. 2 In the last 50 000 years, 10%-20% of bird species have become extinct and many more are threatened, indicating the urgency of genetic conservation. 3 However, the unique reproductive properties of birds make it difficult to directly apply technologies used for genetic rescue in mammals, such as in vitro fertilization and cloning; as an alternative, germline transmission has been pioneered for birds.…”

Competition between the black‐winged kite and Eurasian kestrel led to population turnover at a subtropical sympatric site

“…Other factors may also affect the population dynamics of wintering EKs in Taiwan, such as global or regional population declines, reductions in wintering habitat or changes in wintering sites due to climate change. Monitoring at breeding sites in Northeast Asia, including Japan (Ueta and Uemura 2021), South Korea (Kim et al 2021) and China (China Ornithological Society 2008), has shown that EK populations are stable in these regions, and thus global population decline is unlikely to be the major cause of the reduced records in Taiwan. Although agricultural land in Taiwan is decreasing each year (Chiou et al 2012), the number of BWKs using the same habitat type continues to increase, suggesting that reduced wintering habitat is also not the major reason.…”

Effects of breeding habitat loss on a threatened East Asia migratory forest bird

“…Due to limited monitoring data, the population trends of the majority of forest‐dependent migratory birds in EAAF are unavailable. Exceptions are studies in Japan and South Korea, where the distributions of several forest‐dependent long‐distance migrants are declining based on breeding atlas data (Amano & Yamaura, 2007; Kim et al, 2021; Yamaura et al, 2009). Notably, in these studies, the population decline of migratory birds were seldomly identified with corresponding forest loss in its breeding area, which are consistent with our findings.…”

“…A lack of population trend and threat assessments is putting the migratory landbirds of the East Asian‐Australasian Flyway (EAAF) under threat (Kim et al, 2021; Ueta & Uemura, 2021; Yong et al, 2021). Although it is highly species diverse, supporting the highest number of threatened species among the five global highways (Kirby et al, 2008), very little is known about the population trends of EAAF migratory landbirds (Kim et al, 2021; Newton, 2007; Yong et al, 2021). Such an information gap can result in the late detection of severe population decline (Stanton, 2014).…”