Globally, many pond turtles (Family Emydidae) are of conservation concern due to contracting ranges, increasingly fragmented habitats, and declining populations. One of these turtles, the diamondback terrapin (Malaclemys terrapin), is of concern within the United States, but surveying potential estuarine habitat for the presence of the species requires high levels of time and effort. Here a species-specific, probe-based qPCR assay for identifying terrapin DNA from environmental DNA (eDNA) is described. To expand the utility of this tool, the assay was designed to allow for potential detection of at least 19 other pond turtles taxa and the utility was tested by designing a second species-specific probe for red-eared slider (Trachemys scripta elegans) with a different fluorophore, which can be used simultaneously with the terrapin probe to detect either species. Probes were found to be species-specific and effective at detecting low levels of DNA for the target species, the diamondback terrapin (10 fg/µL) and the red-eared slider (100 fg/µL) in laboratory conditions. The assay also showed species-specific detection in environmental samples taken from field locations where one species or the other were known to reside. Through citizen science approaches, this assay could be used for discovering novel terrapin habitats, monitoring invasive red-eared slider populations or surveying other emydids, with species-specific probes, at a fraction of the cost of traditional surveys.

在全球范围内，许多池塘龟（龟科）由于活动范围缩小、栖息地日益分散和数量下降而受到保护。其中一种海龟，小菜龟（Malaclemys terrapin），在美国受到关注，但调查该物种的潜在河口栖息地需要大量的时间和精力。这里描述了一种基于探针的物种特异性 qPCR 测定，用于从环境 DNA (eDNA) 中识别水龟 DNA。为了扩展该工具的实用性，该测定被设计为能够检测至少 19 种其他池塘龟类群，并通过为红耳龟（Trachemys scripta elegans）设计第二个物种特异性探针来测试该工具的实用性，该探针具有不同的荧光团，可与水龟探针同时使用来检测任一物种。研究发现，探针具有物种特异性，可在实验室条件下有效检测目标物种、小菜斑龟 (10 fg/µL) 和红耳龟 (100 fg/µL) 的低水平 DNA。该测定还显示，在已知存在一种或另一种物种的野外地点采集的环境样本中进行了物种特异性检测。通过公民科学方法，这种测定可用于发现新的水龟栖息地、监测入侵的红耳龟种群或利用物种特异性探针调查其他emydid，而成本只是传统调查的一小部分。