大熊猫GPS项圈行为数据的分类阈值

Analyzed on the Threshold Value of Behavior Data of Giant Panda Colleced by GPS Collar

在大熊猫(Ailuropoda melanoleuca)研究中,利用GPS项圈研究活动节律已经得到广泛应用。但是,由于对GPS项圈行为数据的分类阈值一直缺乏研究,导致了大熊猫个体活动节律分析结果出现一定的偏差。本文以半野化过渡训练区内2只佩戴GPS项圈(Lotek_7000 MU)的大熊猫("倩倩"与"和盛")为研究对象,通过监控视频观测获得休息与活动行为时间段,对比同期利用GPS项圈行为数据计算得到的运动指数,采用正判率最大化策略,确定大熊猫休息和活动两类行为运动指数的行为分类阈值。结果表明,大熊猫休息状态和活动状态运动指数的行为分类阈值为32,而之前研究中采用0作为阈值。以32为阈值对行为分类,其中,休息行为正判率为98.23%,运动行为正判率94.48%;而以0为阈值,休息行为正判率为100%,运动行为正判率77.34%。利用阈值32和0对两只大熊猫19 d的休息行为和活动行为进行分类识别。以0为阈值时,大熊猫日平均活动率("倩倩"为59%;"和盛"为70%),高于以32为阈值得到的日平均活动率("倩倩"为54%;"和盛"为50%),这表明以0为行为分类阈值时,会高估大熊猫活动率。

Though GPS collar has been widely used in studying the activity rhythm of giant panda（Ailuropoda melanoleuca）,unfortunatively,no any analyses have conducted on the reclassified the data collected,that may led to the misunderstand the result.In order to set the threshold value on the behavior data for giant panda,we collected the activity data on two giant panda（Table 1） at Dujiangyan Field Research Center,Chengdu Research Base of Giant Panda Breeding center using both GPS collar and video monitor.Based on the strategy of maximum positive rate,we compared the two set of behavior data（Table 2） collected in the period of May 23 rd,2015 to June 10 th,2015.The results showed there was no significant difference between rest motion index and active motion index for the two giant panda（Fig.1）.Based on our data collected during 19 days,the correct percentage of rest and active behavior gotten from GPS collar was 98.23% and 94.48% compared with the data from video monitor when the threshold was set as 32,respectively.Whereas,the correct percentage of rest and active behavior was 100% when the threshold value was 0 and 77.34%,respectively（Fig.2）.The daily average activity rate of giant pandas based on the threshold of 0 was significantly high than the threshold set on 32（59% vs.54% for panda Qian Qian and 70% vs.50% for panda He Sheng（Fig.3）.Our data suggested that the the activity rate of giant panda may over estimated if the threshold value was set on zero.