Geese have undergone significant changes in their distribution and population size due to human-induced impacts.To improve our understanding of the two main geese populations in East Asia—Greater White-fronted(Anser ...Geese have undergone significant changes in their distribution and population size due to human-induced impacts.To improve our understanding of the two main geese populations in East Asia—Greater White-fronted(Anser albifrons;GWFG)and Bean Geese(Anser fabalis sensu lato;BEAG),which includes the Tundra A.f.serrirostris(TDBG)and Taiga Bean Geese A.f.middendorffii(TGBG),this study estimated their long-and short-term trends and the migration strategies based on their distribution during the migratory and wintering seasons,using nationwide census data collected over 24 years in South Korea.The TRIM(TRends and Indices for Monitoring data)analysis supported a robust long-term population increase since 1999,recently stabilizing around 150,000 individuals in GWFG and 100,000 in TDBG,respectively.But TGBG stabilized at around 7000 with no significant change of population over time.The shorter-term trends within a season suggested that wintering populations of GWFG and TDBG in China might stop over in Korea in their autumn migration before their sea-crossing,evidenced by the large congregation near the Yellow Sea coast followed by a gradual decrease.In contrast to autumn,there was no similar peak in spring migration,suggesting the potential for elliptical migration of some populations around the Yellow Sea.Our findings indicate a growing East Asian population and imply one of the migration strategies of the Greater White-fronted and Tundra Bean Geese.By collaborating with recent tracking data,long-term monitoring efforts could offer more detailed insights into population trends and migration strategies,thereby contributing to the effective management and conservation of goose species in East Asia.展开更多
Scatter hoarding by corvids （crows, jays, magpies, and nutcrackers） provides seed dispersal for many large-seeded plants, including oaks and pines. When hoarding seeds, corvids often choose nonrandom locations throu...Scatter hoarding by corvids （crows, jays, magpies, and nutcrackers） provides seed dispersal for many large-seeded plants, including oaks and pines. When hoarding seeds, corvids often choose nonrandom locations throughout the landscape, resulting in differential survival of seeds. In the context of habitat restoration, such disproportional storing of seeds in areas suitable for germin- ation and establishment can accelerate expansion and recovery of large-seeded tree populations and their associated ecosystems. Here, we investigate the spatial preferences of island scrub jays Aphelocoma insularis during scatter hoarding of acorns （Quercus spp.） on Santa Cruz Island. We use a large behavioral data set on the birds＇ behavior in combination with seedling surveys and spatial analysis to determine whether 1） island scrub jays disproportionally cache seeds in specific habitat types, and 2） whether the preferred habitat type is suitable for oak regeneration. Our results show that the jays nonrandomly cache acorns across the landscape; they use chaparral and coastal sage scrub disproportionally while avoiding open and grassy areas. The areas used most often for caching were also the areas with the highest oak seedling densities. We discuss the potential role of these findings for the recovery of Santa Cruz Island＇s oak habitat since the 1980s.展开更多
基金supported by“The analysis of biogeographical and phenological migration pattern of birds as vectors of avian influenza(0525–202300058)”of the Korea Environment Institute“Long-term change of waterbird population in climate change(NIBR202318101,NIBR202416101)”of the National Institute of Biological Resources in South Korea.
文摘Geese have undergone significant changes in their distribution and population size due to human-induced impacts.To improve our understanding of the two main geese populations in East Asia—Greater White-fronted(Anser albifrons;GWFG)and Bean Geese(Anser fabalis sensu lato;BEAG),which includes the Tundra A.f.serrirostris(TDBG)and Taiga Bean Geese A.f.middendorffii(TGBG),this study estimated their long-and short-term trends and the migration strategies based on their distribution during the migratory and wintering seasons,using nationwide census data collected over 24 years in South Korea.The TRIM(TRends and Indices for Monitoring data)analysis supported a robust long-term population increase since 1999,recently stabilizing around 150,000 individuals in GWFG and 100,000 in TDBG,respectively.But TGBG stabilized at around 7000 with no significant change of population over time.The shorter-term trends within a season suggested that wintering populations of GWFG and TDBG in China might stop over in Korea in their autumn migration before their sea-crossing,evidenced by the large congregation near the Yellow Sea coast followed by a gradual decrease.In contrast to autumn,there was no similar peak in spring migration,suggesting the potential for elliptical migration of some populations around the Yellow Sea.Our findings indicate a growing East Asian population and imply one of the migration strategies of the Greater White-fronted and Tundra Bean Geese.By collaborating with recent tracking data,long-term monitoring efforts could offer more detailed insights into population trends and migration strategies,thereby contributing to the effective management and conservation of goose species in East Asia.
文摘Scatter hoarding by corvids （crows, jays, magpies, and nutcrackers） provides seed dispersal for many large-seeded plants, including oaks and pines. When hoarding seeds, corvids often choose nonrandom locations throughout the landscape, resulting in differential survival of seeds. In the context of habitat restoration, such disproportional storing of seeds in areas suitable for germin- ation and establishment can accelerate expansion and recovery of large-seeded tree populations and their associated ecosystems. Here, we investigate the spatial preferences of island scrub jays Aphelocoma insularis during scatter hoarding of acorns （Quercus spp.） on Santa Cruz Island. We use a large behavioral data set on the birds＇ behavior in combination with seedling surveys and spatial analysis to determine whether 1） island scrub jays disproportionally cache seeds in specific habitat types, and 2） whether the preferred habitat type is suitable for oak regeneration. Our results show that the jays nonrandomly cache acorns across the landscape; they use chaparral and coastal sage scrub disproportionally while avoiding open and grassy areas. The areas used most often for caching were also the areas with the highest oak seedling densities. We discuss the potential role of these findings for the recovery of Santa Cruz Island＇s oak habitat since the 1980s.
