Research output: Contribution to journal › Article › peer-review
Daniel Chadwick, Eleri Pritchard, Paul Bradley, Carl Sayer, Michael Chadwick, Lawrence Eagle, Jan Axmacher
Original language | English |
---|---|
Pages (from-to) | 316-326 |
Number of pages | 11 |
Journal | JOURNAL OF APPLIED ECOLOGY |
Volume | 58 |
Issue number | 2 |
Early online date | 12 Oct 2020 |
DOIs | |
Accepted/In press | 3 Jul 2020 |
E-pub ahead of print | 12 Oct 2020 |
Published | 2 Feb 2021 |
Additional links |
A novel ‘triple drawdown’ method highlights_CHADWICK_Publishedonline12October2020_GOLD VoR (CC BY)
A_novel_triple_drawdown_method_highlights_CHADWICK_Publishedonline12October2020_GOLD_VoR_CC_BY_.pdf, 1.31 MB, application/pdf
Uploaded date:04 Feb 2021
Version:Final published version
Licence:CC BY
Freshwater crayfish can be successful invaders that threaten native biota and aquatic ecosystems in numerous countries worldwide. Nonetheless, the inability of conventional crayfish survey techniques like trapping and handsearching to yield quantitative population data has limited the understanding of crayfish invasion biology and associated ecological impacts. Here, we employed a novel ‘triple drawdown’ (TDD) method to sample invasive populations of signal crayfish Pacifastacus leniusculus in a headwater stream in Northern England. The method was compared with conventional techniques of trapping and handsearching. The TDD method proved to be an effective technique with high capture efficiency, reporting signal crayfish densities from 20.5 to 110.4 animals/m 2 at our study sites. These numbers exceed any previous estimates for similar streams. The TDD showed the vast majority of individuals across all sites were juvenile or sub-adult (<26 mm CL), with only 2.3% of the population large enough (≥35 mm CL) to be caught in standard traps. Synthesis and applications. The triple drawdown (TDD) method demonstrates strong inefficiencies and biases in conventional crayfish survey and management techniques. Trapping is not recommended for representative sampling or control of juvenile dominated populations. TDDs, which can be adapted and modified to operate in multiple habitat types and freshwater systems, generate robust quantitative data on invasive crayfish population demographics in situ. This can advance our understanding of the biology of an important invader of freshwater systems around the world. Obtaining this data prior and post-intervention is fundamental to evaluate invasive crayfish management, and we recommend the TDD method to assess the effectiveness of future control measures.
King's College London - Homepage
© 2020 King's College London | Strand | London WC2R 2LS | England | United Kingdom | Tel +44 (0)20 7836 5454