对大熊猫数量调查方法中咬节区分机制的准确性评价

在目前所广泛应用的大熊猫的数量调查方法中,咬节区分是一种重要的区分机制。本文收集了王朗国家级自然保护区内的同一个熊猫个体的粪便咬节数据,并结合已经发表的同个体粪便咬节数据,对应用咬节区分机制时正确判断的比率进行了评估。通过对17组124团粪便的522个同组内粪便咬节平均值差值的分析,发现在王朗应用2mm的判断阈值时,正确判断的比率为92.9%;卧龙野生种群的正确判断比率为71.2%(1组12团66个差值);圈养种群的正确判断比率为77.6%(7组139团1555个差值),显示咬节区分机制中的2mm阈值具有相当高的准确性。同一团粪便中咬节取样量不足会增加错判的比率,以100咬节测量为对照,30咬节取样会增加3.7%的错判比率,34咬节的测量会增加2.6%的错判比率。

Accuracy assessment of the Bamboo Stem Fragment distinguishing method used in panda population surveys

The Bamboo Stem Fragment (BSF) distinguishing method is an important component of the cur- rently widely applied panda population survey methodology. The threshold for differentiating individuals was based on a difference in average stem fragment size of 2 mm. Droppings from the same individuals were collected in Wanglang National Nature Reserve, and BSF values were measured and analyzed for accuracy assessment of the method. When integrated with other data from published references, the results show that the BSF method has a high correct distinguishing ratio (CDR). In Wanglang, the sample CDR was 92.9%. For the wild panda population of Wolong, the sample CDR was 71.2%, and for the captive panda population, the CDR was 77.6%. One hundred bamboo fragments are typically collected from each dropping. Fewer fragments will decrease the CDR. For example, with 30 fragments the CDR decreases by 3.7%, while with 34 fragments the CDR decreases by 2.6%.