No evidence that crayfish carcasses produce detectable environmental DNA (eDNA) in a stream enclosure experiment

PeerJ

article

Amanda N. Curtis¹  Eric R. Larson¹ 

[1] Program in Ecology, Evolution, and Conservation Biology, University of Illinois at Urbana-Champaign;Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign

关键词: Invasive species;    Endangered species;    Procambarus clarkii;    Red swamp crayfish;    Wildlife management;   

DOI  :  10.7717/peerj.9333

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Environmental DNA (eDNA) is an emerging tool for monitoring invasive and imperiled species, particularly at low densities. However, the factors that control eDNA production, transport, and persistence in aquatic systems remain poorly understood. For example, the extent to which carcasses produce detectable eDNA is unknown. If positive detections are associated with dead organisms, this could confound monitoring for imperiled or invasive species. Here, we present results from one of the first studies to examine carcass eDNA in situ by deploying carcasses of the invasive red swamp crayfish (Procambarus clarkii) in a stream enclosure experiment for 28 days. We predicted that carcasses would initially produce eDNA that would decline over time as carcasses decayed. Unsurprisingly, crayfish carcasses lost biomass over time, but at the conclusion of our experiment much of the carapace and chelae remained. However, no eDNA of P. clarkii was detected in any of our samples at the crayfish density (15 P. clarkii carcasses at ∼615 g of biomass initially), stream flow (520–20,319 L/s), or temperature (∼14–25 °C) at our site. Subsequent analyses demonstrated that these results were not the consequence of PCR inhibition in our field samples, poor performance of the eDNA assay for intraspecific genetic diversity within P. clarkii, or due to the preservation and extraction procedure used. Therefore, our results suggest that when crayfish are relatively rare, such as in cases of new invasive populations or endangered species, carcasses may not produce detectable eDNA. In such scenarios, positive detections from field studies may be more confidently attributed to the presence of live organisms. We recommend that future studies should explore how biomass, flow, and differences in system (lentic vs. lotic) influence the ability to detect eDNA from carcasses.

【 授权许可】

CC BY