Migration Pattern And Stopover Habitat Preferences Of Siberian Cranes

The Siberian Crane Grus leucogeranus was recognized as Critically Endangered in the IUCN Red List since 2000.The global population is about 3500-4000 individuals,of which over 99% belongs to the eastern flyway population.For this long-distance migration species,stopover sites are crucial for completion of the migratory process and successful productivity.Using the satellite tracking data of ten Siberian Cranes from 2016 to 2017,four types of stopover sites were identified based on the length of staying duration;The staging areas were ranked by evaluation model with different weights;the migratory routes were mapped and then we found the conservation gaps.This study aims to(1)explore the migration strategy and pattern of Siberian Cranes,detect the changes the distribution of stopover sites in the past 20 years,evaluate the rank of their importance at different spatial scales,identify the conservation gaps and propose the management recommendations;(2)analyze the diurnal and night movement patterns and habitat utilization preferences of Siberian Cranes in different staging areas,explore Siberian Cranes response process of habitat selection to wetland environmental changes;(3)comprehensively analyze the conservation gaps among stopover sites,and provide conservation suggestions and management strategies.The main results and conclusions are as follows:(1)There was no significant difference in migration parameters between spring and fall season,such as migration distance,staging frequency,staying duration and migration legs.The results show that the migration mode of Siberian Cranes is the energy minimization strategy.The migration route likes the number '8' shape,where western Songnen Plain and Liaohe Plain are located in the narrow bottleneck.The crane adopts the facultative migration,using hopping strategy in a large proportion of potential refueling sites and skipping strategy in order to bypass a poor quality stopover site.(2)A total of 62 and 104 stopover sites were identified in spring and fall seasons,belonging to 23 and 27 staging units/areas of 5 staging regions,respectively.Importantstopover sites included the well-known stopover sites in Zhalong,Momoge and Xianghai National Nature Reserves(NNRs)and their surrounding areas in Western Songnen Plain,and Yellow River Delta of North China Plain.Tumuji NNR of western Songnen Plain,Wolong Lake Provincial Nature Reserve and the eastern Keerqin Sandy Land of Liaohe Plain were newly recognized.Important,common and temporary stopover sites and resting sites were outside the existing protection system by 36.4%,37.5%,40.7% and 72.4%,respectively.In general,the western Songnen Plain is the most important staging areas both in spring and fall.In spring,Liaohe Plain is the second important and Yellow River Delta is the third important.The two staging regions are in the opposite situation in fall.The stopover sites in the Middle and Lower Reaches of the Yangtze River are more important in fall than those in spring,while those in Xing'an Mountains are the opposite.(3)In spring,the diurnal and night home range size in Western Songnen Plain was greater than that at Liaohe Plain without significant differences.While in fall,the diurnal and night home range size in Western Songnen Plain was greater than that in North China Plain with significant differences.There was no significant difference in diurnal or night home range size among staging areas,though Tumuji had the largest diurnal and night home range size.Zhalong had the smallest size of home range in spring,meanwhile the Surrounding area of Yellow River Delta and Middle reaches of Huai River in fall.In different migration seasons,the diurnal home range size in spring was significantly smaller than that in fall at Western Songnen Plain.There was no significant difference in the movement patterns between the Western Songnen Plain and the Liaohe Plain in spring,but there was significant differences between the western Songnen Plain and the North China Plain in fall.In different staging areas,the diurnal movement distance,distance between diurnal and night home range and number of stopover sites used daily in Tumuji were all the largest.The distance between diurnal and night home range in Momoge increased gradually at same migration season..(4)From the aspect of habitat selection,the Siberian Cranes used the artificial habitat during day time in most staging areas except in Zhalong area.At night time,cranes roosted in natural wetlands,except in Tumuji,Surrounding area of Yellow River Delta and Middle ofHuai River.In different stopover regions,there was no significant difference in utilization ratio of artificial habitat at daytime between Liaohe Plain and Western Songnen Plain in spring.In autumn,the Siberian Cranes used artificial habitat at daytime in north China plain was significantly higher than that in west Songnen plain.For different staging areas,Siberian Cranes chose artificial habitat in spring in Tumuji,Xianghai and Momog was significantly higher than that in autumn,and chose artificial habitat all day in Surrounding area of Yellow River Delta and Middle of Huai River in the North China plain.The result indicated that due to wetlands environmental changes,Siberian Cranes had to increase the selection of artificial habitat gradually instead of relying on natural wetlands only to meet their energy replenishment requirements.(5)In the past 20 years,the distribution of stopover sites in China underwent a remarkable change.Liaohe River Delta was not the important stopover site any more in recent years.The intersections of Liaoning,Jilin and Inner Mongolia in the north-central part of Liaohe plain are the newly identified as important staging region.In the Western Songnen Plain,the habitat quality of the Momoge staging area was higher than that of Tumuji,Xianghai and Zhalong.In the North China Plain,the habitat quality of the Wolong Lake was higher than that of Eastern Keerqin Sandy Land.In the North China Plain,three staging areas had different situations.For the important stopovers sites nearby the protected areas,the supervision should be strengthen by relying on the existing organizations;For the important staging sites consist of small size and scattered wetland patches,it is recommended to establish a conservation community,such as the eastern wetland of Keerqin Sandy Land in Inner Mongolia.The interdepartmental and interregional joint protection and management mechanism is proposed for temporary stopover sites and resting sites in North China Plain and the middle and lower reaches of Yangtze River.