青海湖裸鲤自然产卵场的生境特征及无人机遥测判别——以泉吉河为例

The spawning habitat characteristics of Gymnocypris przewalskii and its identification by the UAV in tributary of Qinghai Lake—taking Quanji River as an example

自然产卵场是维持物种延续最关键的栖息地,青海湖裸鲤(Gymnocypris przewalskii)的自然繁殖栖息地状况和生境特征尚缺乏详细的定量研究。以青海湖入湖河流泉吉河为例,在平水期采用现场调查和无人机遥测的方法对青海湖裸鲤的自然产卵场分布及生境状况进行调查,确定其产卵场生境特征参数,建立基于无人机遥测识别产卵场的方法并进行复核验证。结果表明:泉吉河河道形态可分为弯曲型、分汊型和顺直型等三种典型河型,青海湖裸鲤自然产卵场主要分布在弯曲型和分汊型河道中,分汊型河道几乎100%都有产卵场分布,弯曲型河道有70%为产卵场;产卵场河道平均长度(135.13±61.13)m,平均宽度(30.01±17.51)m,平均曲折度1.09±0.07;平均面积(4586.6±4201.61)m^(2);产卵场常位于缓水浅滩处,平均水深(0.19±0.10)m(范围:0.03-0.44m),平均流速(0.24±0.20)m/s(范围:0.01-0.81m/s),河床质为含有沙粒的卵石(粒径:163-256mm)底质。河道形态、沙洲分布、水深特征等特征参数可作为无人机遥测识别产卵场的判断条件,并实现验证成功。研究结果可为开展整个流域的青海湖裸鲤自然产卵场现状评估及保护对策制定提供技术支撑。

The natural spawning grounds are the most critical habitat for maintaining the Gymnocypris przewalskii resources in the Qinghai Lake,while they were not well studied yet.This study aims at analyzing the habitat characteristics of the spawning grounds of G.przewalskii in one of the tributaries of the Qinghai Lake,Quanji River,via field survey and unmanned aerial vehicle(UAV)identification technique.The results showed that the morphology of Quanji River could be divided into three types:meandering,braided and straight river channels.The natural spawning grounds of G.przewalskii were mostly located in the braided river channel(100%),less in the meandering channel(70%),and rare in the straight channel.The average length,width,tortuosity and area of the spawning grounds in the Quanji River was(135.13±61.13)m,(30.01±17.51)m,(1.09±0.07)and the(4586.60±4201.61)m^(2),respectively.The spawning grounds often located in the river with riffles,the average water depth was(0.19±0.10)m(range 0.03-0.44m)and an average velocity was(0.24±0.20)m/s(range 0.01-0.81m/s),the substrate was pebble and sand(particle size 16-256mm).The riverbank morphology,the distribution of the island and the water depth could be used in UAV image for identifying the potential spawning grounds in the whole Quanji River,the result can be verified by the field data.The research is benefit for the assessment and protection of the natural spawning grounds for G.przewalskii and provides a case study for future spawning grounds investigation in some tough field survey areas.