Colorado Parks and Wildlife, Fort Collins, Colorado, United States of America.
Colorado Parks and Wildlife, Montrose, Colorado, United States of America.
PLoS One. 2020 Apr 10;15(4):e0227088. doi: 10.1371/journal.pone.0227088. eCollection 2020.
Traditional methods of collecting, sorting, and identifying benthic macroinvertebrate samples are useful for stream biomonitoring and ecological studies, however, these methods are time consuming, expensive, and require taxonomic expertise. Estimating larval densities through collection of post-emergent exuvia can be a practical and time efficient alternative. We evaluated the use of multiple pass depletion techniques of the post-emergent exuvia of Pteronarcys californica to estimate larval densities at ten sites in three Colorado rivers. Exuvia density was highly correlated with both final-instar larval density (R2 = 0.90) and total larval density (R2 = 0.88) and the multiple pass removal technique performed well. Exuvia surveys found P. californica at three low density sites where benthic sampling failed to detect it. At moderate and high density sites the exuvia surveys always produced lower density estimates than benthic surveys. Multiple pass depletion estimates of exuvia proved to be an accurate and efficient technique at estimating larval densities and provided an effective alternative for traditional benthic sampling when objectives are detecting and monitoring P. californica, especially at low density sites.
传统的底栖大型无脊椎动物样本采集、分类和鉴定方法在溪流生物监测和生态研究中非常有用，但这些方法耗时、昂贵，并且需要分类学专业知识。通过收集刚羽化的外骨骼来估计幼虫密度是一种实用且高效的替代方法。我们评估了多次耗尽加利福尼亚石蛾羽化外骨骼的技术，以估计科罗拉多州三条河流中的十个地点的幼虫密度。外骨骼密度与终龄幼虫密度（R2 = 0.90）和总幼虫密度（R2 = 0.88）高度相关，且多次去除技术效果良好。外骨骼调查在三个低密度地点发现了加利福尼亚石蛾，而底栖采样未能检测到它。在外骨骼密度和幼虫密度都较高的地点，外骨骼调查总是产生比底栖调查更低的密度估计值。多次去除外骨骼的技术证明是一种准确高效的技术，可以估计幼虫密度，并为传统的底栖采样提供了有效的替代方法，特别是在低密度地点。
