Environmental DNA‐based methods detect the invasion front of an advancing signal crayfish population

Aquatic invasive species, such as the signal crayfish (Pacifastacus leniusculus), present a major threat to freshwater ecosystems. However, these species can be challenging to detect in recently invaded habitats. Environmental DNA (eDNA)–based methods are highly sensitive and capable of detecting ju...

Full description

Saved in:

Bibliographic Details
Published in:	Environmental DNA (Hoboken, N.J.) Vol. 4; no. 3; pp. 596 - 607
Main Authors:	Greenhalgh, Jack A., Collins, Rupert A., Edgley, Duncan E., Genner, Martin J., Hindle, Jan, Jones, Gareth, Loughlin, Lesley, O’donnel, Maire, Sweet, Michael J., Battarbee, Richard W.
Format:	Journal Article
Language:	English
Published:	Hoboken John Wiley & Sons, Inc 01-05-2022 Wiley
Subjects:	Aquatic ecosystems Aquatic populations Crayfish Creeks & streams Current distribution Deoxyribonucleic acid Dispersal DNA Ecosystems eDNA freshwater ecology Freshwater ecosystems Genetic testing Geomorphology Introduced species Invasive species Nonnative species Pacifastacus leniusculus Plastics Sampling Searching Statistical analysis Stream water Streams Tributaries Trout upland streams Water chemistry United Kingdom > UK
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Aquatic invasive species, such as the signal crayfish (Pacifastacus leniusculus), present a major threat to freshwater ecosystems. However, these species can be challenging to detect in recently invaded habitats. Environmental DNA (eDNA)–based methods are highly sensitive and capable of detecting just a few copies of target DNA from non‐invasively collected samples. Therefore, they have considerable potential for broad‐scale use in mapping and monitoring the spread of invasive species. In this study, we aimed to increase our understanding of the current distribution of signal crayfish in a headwater stream system in the United Kingdom (tributaries of the River Wharfe, Addingham, Yorkshire). Environmental DNA sampling, assessment of water chemistry variables, and conventional crayfish hand‐searching were conducted across 19 study sites in five tributary streams. Using hand‐searching, we detected signal crayfish at 26% of the sites (5/19 study sites). However, using eDNA‐based methods, occupancy increased to 47% of study sites (9/19). Our sampling revealed previously unknown sites of crayfish occupancy, and using eDNA‐based methods, we were able to define the geographical extent of the invasion front in each headwater stream sampled. This study highlights that eDNA‐based methods are well‐suited for detecting newly established signal crayfish populations in recently invaded habitats, even when the invasive species is at low abundance and, therefore, might otherwise be under‐represented or undetected using conventional survey methods. Our study provides further evidence that headwater stream ecosystems are particularly vulnerable to signal crayfish invasion. However, their geomorphological features may make methods used to reduce or prevent invasive crayfish dispersal more effective than in other freshwater ecosystems. In this study, we aimed to increase our understanding of the current distribution of signal crayfish in an upland stream system in the North of the United Kingdom (Addingham, Yorkshire). As a result of the survey, we discovered two new sites of crayfish occupancy in two tributaries of the River Wharfe. To conclude, this study highlights eDNA‐based methods are well suited for detecting establishing signal crayfish populations in recently invaded habitats even when the invasive species is at low abundance and therefore might otherwise be underrepresented or undetected using conventional survey methods.
Bibliography:	Genner and Battarbee joint senior co‐authors.
ISSN:	2637-4943 2637-4943
DOI:	10.1002/edn3.280