Long distance (>20 km) downstream detection of endangered stream frogs suggests an important role for eDNA in surveying for remnant amphibian populations

PeerJ

article

Cecilia Villacorta-Rath¹  Conrad J. Hoskin²  Jan M. Strugnell²  Damien Burrows¹ 

[1] Centre for Tropical Water and Aquatic Ecosystem Research ,(TropWATER), James Cook University;College of Science and Engineering, James Cook University;Centre for Sustainable Tropical Fisheries and Aquaculture, College of Science and Engineering, James Cook University

关键词: eDNA transport;    Environmental DNA;    Endangered species;    Monitoring;    Precipitation;    Tropics;   

DOI  :  10.7717/peerj.12013

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Background Globally, amphibian species have suffered drastic population declines over the past 40 years. Hundreds of species are now listed as Critically Endangered, with many of these considered “possibly extinct”. Most of these species are stream-dwelling frogs inhabiting remote, montane areas, where remnant populations are hard to find using traditional surveys. Environmental DNA (eDNA) could revolutionize surveys for ‘missing’ and endangered amphibian populations by screening water samples from downstream sections to assess presence in the upstream catchments. However, the utility of this survey technique is dependent on quantifying downstream detection probability and distances. Methods Here we tested downstream detection distances in two endangered stream frogs (Litoria lorica and L. nannotis) that co-occur in a remote stream catchment in north-east Australia, and for which we know precise downstream distributional limits from traditional surveys. Importantly, the two last populations of L. lorica persist in this catchment: one small (~1,000 frogs) and one very small (~100 frogs). We conducted eDNA screening at a series of sites kilometers downstream from the populations using precipitation from two fixed water volumes (15 and 100 mL) and via water filtering (mean 1,480 L). Results We detected L. nannotis and the small L. lorica population (~1,000 frogs) at most sampling sites, including 22.8 km downstream. The filtration method was highly effective for far-downstream detection, as was precipitation from 100 mL water samples, which also resulted in consistent detections at the far-downstream sites (including to 22.8 km). In contrast, we had limited downstream detection success for the very small L. lorica population (~100 frogs). Discussion 20 km) suggest eDNA is a valuable tool for detecting rare stream amphibians. We provide recommendations on optimal survey methods.

【 授权许可】

CC BY