Establishing effective wildlife conservation measures requires accurate demographic information such as population size and survival probability: parameters that can be extremely difficult to obtain. This is especially the case for threatened species, which are often rare and sometimes occupy inaccessible areas. While noninvasive genetic sampling (NIGS) techniques are promising tools for providing demographic data, these methods may be unreliable in certain situations. For instance, fecal samples of frugivorous species in tropical areas degrade rapidly, affecting the usability of the genetic material. In this study, we compared (1) NIGS capture–mark–recapture (NIGS-CMR) with conventional CMR to determine their potential in estimating demographic parameters of fruit bats, and (2) the precision of these demographic parameters and the associated costs given varying sampling designs through simulations. Using Livingstone’s fruit bats (Pteropus livingstonii) fecal samples, microsatellite markers were tested and genotyping success and error rates were assessed. The average genotyping success rate was 77%, and the total genotyping error rate for all loci was low (allelic dropout rate = 0.089, false alleles rate = 0.018). Our results suggested that five loci were required to identify individuals. Simulations showed that monitoring the species over a 9-yr period with a recapture rate of 0.20 or over a 6-yr period with a recapture rate of 0.30 seems appropriate to obtain valuable demographic parameters. Overall, in comparison to conventional CMR, NIGS-CMR offers a better method for estimating demographic parameters and subsequently for conducting long-term population monitoring in flying foxes due to the fact that (1) sample collection is easy and the level of genotyping errors in the laboratory is low and (2) it is cheaper, less time-consuming, and less disturbing to individual animals. We strongly advocate an approach that couples a pilot study with simulations as done in this study in order to choose the most efficient monitoring method for a given species or context.

中文翻译：

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飞狐的无创基因采样：监测人口统计参数的一种有价值的方法

建立有效的野生动物保护措施需要准确的人口统计信息，例如种群规模和生存概率：这些参数极难获得。对于受威胁的物种来说尤其如此，它们通常是稀有的，有时占据无法进入的区域。虽然无创基因采样 (NIGS) 技术是提供人口统计数据的有前途的工具，但这些方法在某些情况下可能不可靠。例如，热带地区食果物种的粪便样本会迅速降解，从而影响遗传材料的可用性。在这项研究中，我们将 (1) NIGS 捕获-标记-重新捕获 (NIGS-CMR) 与传统 CMR 进行了比较，以确定它们在估计果蝠人口统计参数方面的潜力，(2) 这些人口统计参数的精确度和通过模拟给出不同抽样设计的相关成本。使用利文斯通的果蝠（紫檀) 粪便样本、微卫星标记进行了测试，并评估了基因分型成功率和错误率。平均基因分型成功率为 77%，所有基因座的总基因分型错误率较低（等位基因丢失率 = 0.089，假等位基因率 = 0.018）。我们的结果表明需要五个基因座来识别个体。模拟表明，在 9 年期间以 0.20 的重新捕获率或在 6 年期间以 0.30 的重新捕获率监测物种似乎适合获得有价值的人口统计参数。总体而言，与传统的 CMR 相比，NIGS-CMR 提供了一种更好的方法来估计人口统计参数并随后用于对狐蝠进行长期种群监测，因为 (1) 样本收集容易且实验室中的基因分型错误水平较低 (2)它更便宜，更省时，对个别动物的干扰更少。我们强烈提倡将试点研究与本研究中所做的模拟相结合的方法，以便为给定的物种或环境选择最有效的监测方法。