甘肃盐池湾黑颈鹤筑巢栖息地偏好及人为干扰的影响

Nesting habitat preference of the black-necked crane and influence of anthropogenic disturbance in Yanchiwan,Gansu

作为高原旗舰物种,黑颈鹤(Grus nigricolli)是反映高原生态健康状况的重要参考。为了解黑颈鹤如何在多因素作用下适应人类改造过的栖息地环境,本研究利用遥感解译、最近邻分析与随机森林模型对繁殖于甘肃盐池湾国家级自然保护区党河湿地的黑颈鹤的筑巢栖息地偏好及人为干扰进行研究。2019年和2020年每年的4-9月在党河湿地内对巢位点等数据进行收集。研究结果表明:党河湿地内巢址与人为干扰的分布位置明显不同,两者的主要分布区呈现镶嵌状。距深水沼泽距离、距浅水沼泽距离与距湖泊距离是影响黑颈鹤筑巢栖息地选择最关键的3个环境因子。黑颈鹤筑巢时偏好在距离深水沼泽<125 m、距离浅水沼泽<130 m、距离湖泊<270 m的区域内筑巢。黑颈鹤对沼泽、湖泊等资源的偏好是其巢址分布格局的主要驱动力,而房屋与公路等人为干扰对栖息地选择的影响很小。黑颈鹤筑巢时强烈偏好的栖息地在湿地内占比低、分布聚集且适宜范围有限,繁殖区域较狭窄。黑颈鹤巢址间距离的上升表明黑颈鹤栖息地质量可能有所下降,牲畜数量的增长、冬季牧场的多季节利用以及气候变化可能是主要原因。建议在党河湿地内不新增房屋及公路等人为干扰,同时继续适当限牧,并给予牧民充足的经济补偿。

Aims:The black-necked crane(Grus nigricollis)is a flagship species of plateau and an important indicator of the health status of the plateau ecosystem.In recent years,plenty of research on black-necked cranes has been implemented,but these studies mainly focus on the migration,nest site selection,and foraging habitat selection of black-necked cranes.We know little about the preference of nesting habitat of black-necked cranes and the selection mechanism of nesting habitat.Black-necked cranes are divine birds in Tibetan Buddhism,and the species has always lived in harmony with the believers of Tibetan Buddhism.However,with the progression of human lifestyle,the problem of anthropogenic disturbance has become more prominent.Our research aims to provide a reference for understanding how black-necked cranes adapt to human modified habitats between multiple factors.Methods:Nest sites and number of black-necked cranes were collected in Danghe Wetland from April to September in 2019 and 2020.Satellite interpretation was utilized to classify the habitats of the black-necked cranes.To study the distribution pattern of the nests and anthropogenic disturbance,we used nearest neighbor analysis and kernel density estimation.A random forest model was applied to explore nesting habitat selection mechanism of the black-necked cranes.Results:There are two concentrated breeding grounds of black-necked crane nests in the Danghe Wetland and the nests are extremely concentrated.The two breeding grounds are located in the marsh in the north and south of the Danghe River.The houses of herders in the wetland are distributed in a strip on the gobi at the southern edge of the wetland.The density distribution of house is more concentrated on the south bank of the Danghe River,and the roads are also distributed along the south bank of the Danghe River.There is obvious geographical separation between the black-necked crane nests and anthropogenic disturbances.Meadows are the most prominent landscape type of wetland ecosystems and the sum of the proportions of marsh meadow and salinized meadow exceeds 50%.The proportion of shallow water marsh is relatively small,not exceeding 10%in two years.Deep water marsh and lake have smaller areas,below 3%and 2%respectively(average of two years).The distance from deep water marsh,shallow water marsh,and lake are the three critical environmental variables affecting the nesting habitat selection of the black-necked cranes,while the distance from houses and roads are less critical.The black-necked cranes prefer to nest in areas<125 m from deep water marsh,<130 m from shallow water marsh,and<270 m from lake.Conclusion:The deep water marsh,which the black-necked cranes strongly prefer when nesting in Danghe Wetland,is characterized by a relatively low percentage and clustered distribution.Meanwhile,the range of suitable habitat for the black-necked cranes to nest is narrow(<125 m from deep water marsh,<130 m from shallow water marsh,<270 m from lake).Therefore,the breeding distribution of black-necked cranes is narrow.Resource factors are the main driving force for the distribution pattern of the black-necked crane nests.However,anthropogenic disturbance has little impact on nesting habitat selection.Therefore,the geographical separation between the black-necked crane nests distribution and anthropogenic disturbance is largely due to the preference for resources rather than avoiding disturbance.The habitat quality of the black necked-cranes in Danghe Wetland may decline,and the increase of livestock,multi-season utilization of pasture,and climate change may be the main reasons.