Stopover sites were identified using the space—time permutation model from the SaTScan statistics. Despite its importance for migratory waterbirds, the Northeast China Plain experienced a considerable loss of natural waterbodies and wetlands in the period from to Gong et al.
We overlapped the protected areas with the GPS locations location records in flight were excluded of tracked geese and calculated the percentage of locations falling into protected areas. Our study illustrates how satellite tracking combined with spatial analyses can be used to guide conservation efforts.
A lack of protected areas along flyways is a general problem for migratory bird species all around the world Runge et al. For identified stopover sites, central locations and radiuses were used to describe the range of each site. Selection rates were standardized to 0— to assist comparison. Besides geese, Endangered Siberian cranes also use this region extensively during spring Kanai et al.
Birds were promptly released at the capture site after transmitters were deployed the average time between capture and release was 6 hr. Tundra bean geese in general departed 1 month earlier at the end of February or the beginning of March from Yangtze. Moreover, hardly any of the areas that geese intensively utilize during their spring migration are formally protected. Geese are highly adaptable and able to survive under simple habitat conservation and restoration measures e.
Geese stopping over in the Northeast China Plain were observed to graze on newly flushed spring meadows near waterbodies after ice melt personal communication with local farmers. Eight land cover types were included as follows: water, croplands, forests, grasslands, wetlands, shrublands, barelands, and tundra.
Detailed information about the central location and radius of stopover sites, cumulative staging periods, and the of individuals that used each site are summarized in Supporting information Table S3. The locations of the main stopover sites showed a good match with the intensively used areas at the multibird level. Zhenlai and Nenjiang are the two most frequently utilized sites where geese spent cumulatively days 14 individuals and days 11 individuals; Supporting information Table S3.
Additionally, main stopover sites were found in Russia Kobyayskiy, Zhiganskiy, and Verkhoyanskiy Districtswhere geese stayed cumulatively 18 two individuals to 32 six individuals days before they migrated to their likely breeding site at the Lena Delta and the Yana Delta Supporting information Table S3. Based on full tracks only, the period of spring migration lasted 53—92 days, stretching over 5, km, with a total duration of stay of 43—81 days between 4 and 15 stopover sites, of which 32—49 days were spent in the Northeast China Plain.
Geese stopping over in the Northeast China Plain prefers aggregated waterbodies, surrounded by scattered croplands at the foraging scale Zhang et al. Hence, understanding the ecology of bird migration is crucial for the conservation of migratory species.
Waterbodies are most vulnerable to the land conversion associated with the development of agriculture. Ecol Evol. Individuals with full tracks spent most of their staging time over a month in this area. Breeding populations in Russia have shown a rapid decline since the s Syroechkovskiy, East Asian populations mainly winter in eastern China, Korea, and Japan.
Both habitat selection and protection status analyses were performed in the ArcGIS software version A detailed description on the estimation of the utilization distribution with the dynamic Brownian bridge movement model, the identification of stopover sites using the space—time permutation model, and the calculation of migration schedule, travel distances, of stopover sites, and the length of stay can be found in Supporting information Appendix S1.
No full tracks were obtained for tundra bean geese and the farthest an individual reached was northeast Siberia Figure 1 b. Details on the deation and protection status of these overlapping areas are summarized in Supporting information Table S4. Brown dots indicate recorded GPS locations.
The deterioration of the crucial stopover sites in the Northeast China Plain, together with the natural habitat loss in the wintering sites Yu et al. Moreover, the potential bird—human conflict in core stopover area needs to be further studied. Spring migration patterns, habitat use, and stopover site protection status for two declining waterfowl species wintering in China as revealed by satellite tracking. By further investigating the habitat selection of the two study species at their main stopover sites, we show that water yields the highest selection rate area used against area available at a specific stopover site across most sites, followed by potential foraging lands including crop, wetland, bareland, and grass.
Although hunting remains a problem, habitat loss and degradation of stopover and wintering sites, especially those in China, are considered the main threat de Boer et al. The main stopover sites were defined as those where at least two individuals stayed for cumulatively no less than 2 weeks. Among the global network of migratory waterfowl flyways, the Asian flyways are the least studied in terms of migration ecology, while they are characterized by the most pronounced human—bird conflicts Si, Xin, Prins, et al.
National Center for Biotechnology InformationU. Journal List Ecol Evol v. Moreover, for each individual, we identified the departure and arrival dates, the flight distances in between stopover sites, and the duration of stays at each stopover site. Future ground surveys should be carried out to validate the habitat use of migratory waterfowl at a population level in these core stopover areas. Cumulative probability contours were calculated to represent the relative use at both individual and multibird levels.
As both tracked species partially forage on agricultural land in the Northeast China Plain, potential bird—human conflict needs to be further studied. P contributed materials and analysis tools; Y. All authors edited the manuscript and approved the final version for publication.
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East Asian migratory waterfowl have greatly declined since the s, especially the populations that winter in China. Using the identified multibird level utilization distribution, we calculated the percentage of the core areas that are under protection. There are regular waterfowl surveys along the Yangtze River Floodplain. Although only a limited of individuals were tracked including some partial tracks that do not cover the entire spring migration route and bearing loggers might affect migration behavior, this study provides the first insight into important stopover sites for East Asian waterfowl wintering in China.
Ltd; B, Blueoceanix Technology Co. Both species show some preference for other foraging lands such as grass, wetland, and bareland in a few sites. Due to fast economic development, the and size of natural wetlands have declined considerably in eastern China from the s onwards Gong et al.
Partial conversion of natural wetlands into agriculture could be beneficial for foraging, as exemplified by the use of cropland by our tracked geese. However, no census data are available to evaluate the situation of migratory waterfowl at the Northeast China Plain. In order to generate concrete protection measures in the Northeast China Plain, future studies need to further investigate these potential sources of bird—human conflict.
Spring migration patterns, habitat use, and stopover site protection status for two declining waterfowl species wintering in china as revealed by satellite tracking
Agricultural lands are therefore heavily used by geese, especially when lakes are still frozen upon arrival. A similar scenario was found for Siberian crane Women for wild sex in Stopover Kentucky et al. Geese with full tracks spent their longest staging period in the Northeast China Plain Table 1Figure 1. However, massive wetland loss, in particular due to the conversion of important roosting lakes and wetlands into agricultural land, is expected to negatively affect waterfowl survival.
Besides water and natural foraging lands, cropland was highly selected at some sites. Full tracks were defined as individuals that managed to return to the Yangtze River Plain the next season, whereas partial tracks were defined as individuals that travelled at least 1, km away from the wintering site before the al was lost. Specifically, we divided the percentage of GPS locations on one land cover type by the percentage of pixels covered by this land cover type within the boundary of a specific stopover site described by the center coordinates and radius of each site calculated by the space—time permutation model.
Stopover sites in China are named by county and those in Russia are named by district only those main sites where at least two individuals stayed for cumulatively no less than 2 weeks are shown. The protected areas available for geese in China are less than in Russia Figure 2. Despite the rapid decline of East Asian waterfowl species, critical knowledge gaps concerning their migration ecology remain. Our study illustrates how satellite tracking combined with spatial analyses can provide crucial insights necessary to improve the conservation of declining Migratory species.
We used the GPS locations covering the period from 3 days before birds left the wintering site until 3 days after they reached their likely breeding sites to describe a complete spring migration route for partial tracks, data until the last available record were used.
We recommend integrating waterbodies at critical stopover sites, used as core roosting area, into the network of protected areas. Detailed migration periods, count of days, and locations for each individual are reported in Supporting information Table S2. Despite missing GPS records due to satellite acquisition failure or low battery level, we collected on average ten locations per bird per day.
Waterbodies are typical roosting sites and geese prefer foraging sites in close proximity to their roosts Ackerman et al.
This region has also been intensely developed for agriculture, suggesting a causal link to the decline in East Asian waterfowl wintering in China. The protection of waterbodies used as roosting area, especially those surrounded by intensive foraging land, is critical for waterfowl survival. While the threatened swan goose Anser cygnoidesbreeding in Mongolia, has been satellite tracked Batbayar et al.
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We aim to a estimate the habitat utilization distribution of tracked geese and identify the stopover sites during spring migration; b summarize migration timing and distance and of stopover sites and length of stay; c investigate habitat selection and site protection status along migration routes; and finally, d discuss the implications of our findings for the conservation of declining waterfowl species wintering in China.
Conservation is severely hampered by the lack of primary information about migration patterns and stopover sites.
The migration routes and stopover sites for the populations of these two goose species wintering in China are as yet unknown. Hence, the protection of waterbodies used as roosting area, especially those surrounded by foraging land, is critical for waterfowl survival. The protection of waterbodies used as the core roosting area, especially those surrounded by foraging land, is critical for the survival of waterfowl. Both species tend to spend an extended period of time in a few neighboring stopover sites at the Northeast China Plain. However, as water was most highly selected by these birds, completely eradicating waterbodies would be disastrous to waterfowl.
Synchrony between distribution and resources also makes migratory birds particularly vulnerable to alterations in food availability along the flyway by global climate and land cover change Drent et al. Moreover, intensive human activities can reduce foraging effectiveness. All tracked individuals stopped over in the Northeast China Plain.
Birds were placed individually into bags and immediately transported to the closest handling station. of staying individuals and cumulative staying days were reported for these main stopover sites.