Höing Andrea, Quinten Marcel C, Indrawati Yohana Maria, Cheyne Susan M, Waltert Matthias
Department of Conservation Biology, Centre for Nature Conservation, Georg-August-Universität Göttingen, 37073 Göttingen, Germany.
Int J Primatol. 2013 Feb;34(1):148-156. doi: 10.1007/s10764-012-9655-7. Epub 2013 Jan 8.
Estimating population densities of key species is crucial for many conservation programs. Density estimates provide baseline data and enable monitoring of population size. Several different survey methods are available, and the choice of method depends on the species and study aims. Few studies have compared the accuracy and efficiency of different survey methods for large mammals, particularly for primates. Here we compare estimates of density and abundance of Kloss' gibbons () using two of the most common survey methods: line transect distance sampling and triangulation. Line transect surveys (survey effort: 155.5 km) produced a total of 101 auditory and visual encounters and a density estimate of 5.5 gibbon clusters (groups or subgroups of primate social units)/km. Triangulation conducted from 12 listening posts during the same period revealed a similar density estimate of 5.0 clusters/km. Coefficients of variation of cluster density estimates were slightly higher from triangulation (0.24) than from line transects (0.17), resulting in a lack of precision in detecting changes in cluster densities of <66 % for triangulation and <47 % for line transect surveys at the 5 % significance level with a statistical power of 50 %. This case study shows that both methods may provide estimates with similar accuracy but that line transects can result in more precise estimates and allow assessment of other primate species. For a rapid assessment of gibbon density under time and financial constraints, the triangulation method also may be appropriate.
估算关键物种的种群密度对许多保护项目至关重要。密度估算提供了基线数据，并能对种群数量进行监测。有几种不同的调查方法可供选择，方法的选择取决于物种和研究目的。很少有研究比较不同调查方法对大型哺乳动物，特别是灵长类动物的准确性和效率。在这里，我们使用两种最常见的调查方法：样线距离抽样法和三角测量法，比较了克氏长臂猿的密度和丰度估算。样线调查（调查工作量：155.5公里）共产生了101次听觉和视觉相遇事件，密度估算为5.5个长臂猿集群（灵长类社会单位的群体或亚群体）/公里。同期从12个监听点进行的三角测量得出的密度估算值相似，为5.0个集群/公里。集群密度估算的变异系数，三角测量法（0.24）略高于样线法（0.17），这导致在5%的显著性水平和50%的统计功效下，三角测量法检测集群密度变化小于66%，样线调查检测集群密度变化小于47%时缺乏精度。本案例研究表明，两种方法可能提供相似准确性的估算，但样线法能得出更精确的估算，并允许对其他灵长类物种进行评估。在时间和资金有限的情况下，为快速评估长臂猿密度，三角测量法也可能适用。
