Woodruff S P, Johnson T R, Waits L P
Department of Fish and Wildlife Sciences, University of Idaho, Moscow, ID, 83844-1136, USA.
Department of Statistical Science, University of Idaho, Moscow, ID, 83844-1104, USA.
Mol Ecol Resour. 2015 Jul;15(4):843-54. doi: 10.1111/1755-0998.12362. Epub 2014 Dec 28.
Knowledge of population demographics is important for species management but can be challenging in low-density, wide-ranging species. Population monitoring of the endangered Sonoran pronghorn (Antilocapra americana sonoriensis) is critical for assessing the success of recovery efforts, and noninvasive DNA sampling (NDS) could be more cost-effective and less intrusive than traditional methods. We evaluated faecal pellet deposition rates and faecal DNA degradation rates to maximize sampling efficiency for DNA-based mark-recapture analyses. Deposition data were collected at five watering holes using sampling intervals of 1-7 days and averaged one pellet pile per pronghorn per day. To evaluate nuclear DNA (nDNA) degradation, 20 faecal samples were exposed to local environmental conditions and sampled at eight time points from one to 124 days. Average amplification success rates for six nDNA microsatellite loci were 81% for samples on day one, 63% by day seven, 2% by day 14 and 0% by day 60. We evaluated the efficiency of different sampling intervals (1-10 days) by estimating the number of successful samples, success rate of individual identification and laboratory costs per successful sample. Cost per successful sample increased and success and efficiency declined as the sampling interval increased. Results indicate NDS of faecal pellets is a feasible method for individual identification, population estimation and demographic monitoring of Sonoran pronghorn. We recommend collecting samples <7 days old and estimate that a sampling interval of four to seven days in summer conditions (i.e., extreme heat and exposure to UV light) will achieve desired sample sizes for mark-recapture analysis while also maximizing efficiency [Corrected].
了解种群人口统计学对于物种管理很重要，但对于低密度、分布广泛的物种来说可能具有挑战性。对濒危的索诺兰叉角羚（Antilocapra americana sonoriensis）进行种群监测对于评估恢复工作的成效至关重要，与传统方法相比，非侵入性DNA采样（NDS）可能更具成本效益且侵入性更小。我们评估了粪便颗粒沉积率和粪便DNA降解率，以最大限度地提高基于DNA的标记重捕分析的采样效率。在五个水坑收集沉积数据，采样间隔为1至7天，平均每只叉角羚每天有一堆粪便。为了评估核DNA（nDNA）的降解情况，将20份粪便样本暴露于当地环境条件下，并在1至124天的八个时间点进行采样。六个nDNA微卫星位点的平均扩增成功率在第一天的样本中为81%，到第七天为63%，到第十四天为2%，到第六十天为0%。我们通过估计成功样本的数量、个体识别成功率和每个成功样本的实验室成本，评估了不同采样间隔（1至10天）的效率。随着采样间隔的增加，每个成功样本的成本增加，成功率和效率下降。结果表明，粪便颗粒的NDS是索诺兰叉角羚个体识别、种群估计和种群统计学监测的可行方法。我们建议收集年龄小于7天的样本，并估计在夏季条件下（即酷热和暴露于紫外线下）四到七天的采样间隔将实现标记重捕分析所需的样本量，同时也能最大限度地提高效率[已修正]。
