Fringe effects: detecting bull trout ( Salvelinus confluentus) at distributional boundaries in a montane watershed
Robust assessment and monitoring programs are critical for effective conservation, yet for many taxa we fail to understand how trade-offs in sampling design affect power to detect population trends and describe spatial patterns. We tested an occupancy-based sampling approach to evaluate design consi...
Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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crcansciencepubl:10.1139/cjfas-2020-0219 2024-09-15T18:26:37+00:00 Fringe effects: detecting bull trout ( Salvelinus confluentus) at distributional boundaries in a montane watershed Mochnacz, Neil J. MacKenzie, Darryl I. Koper, Nicola Docker, Margaret F. Isaak, Dan J. 2021 http://dx.doi.org/10.1139/cjfas-2020-0219 https://cdnsciencepub.com/doi/full-xml/10.1139/cjfas-2020-0219 https://cdnsciencepub.com/doi/pdf/10.1139/cjfas-2020-0219 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Fisheries and Aquatic Sciences volume 78, issue 8, page 1030-1044 ISSN 0706-652X 1205-7533 journal-article 2021 crcansciencepubl https://doi.org/10.1139/cjfas-2020-0219 2024-08-29T04:08:50Z Robust assessment and monitoring programs are critical for effective conservation, yet for many taxa we fail to understand how trade-offs in sampling design affect power to detect population trends and describe spatial patterns. We tested an occupancy-based sampling approach to evaluate design considerations for detecting watershed-scale population trends associated with juvenile bull trout (Salvelinus confluentus) distributions. Electrofishing surveys were conducted across 275 stream sites from the Prairie Creek watershed, Northwest Territories, Canada. Site-level detectability of juvenile bull trout was not uniform, and imperfect detection affected modelled occupancy probabilities most in fringe habitats near distributional boundaries in steep reaches and large streams. We show that detecting a 30% change in watershed-level occupancy ≥78% of the time, as conservation guidelines suggest, may require three repeat surveys (i.e., temporal replicates) and increased spatial sampling intensity of fringe habitats. Additional sampling effort in fringe sites could be offset by sampling fewer sites in core habitats to optimize designs for detecting demographic shifts in bull trout, while still minimizing risk of nondetection for this cryptic species. Article in Journal/Newspaper Northwest Territories Canadian Science Publishing Canadian Journal of Fisheries and Aquatic Sciences |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
Robust assessment and monitoring programs are critical for effective conservation, yet for many taxa we fail to understand how trade-offs in sampling design affect power to detect population trends and describe spatial patterns. We tested an occupancy-based sampling approach to evaluate design considerations for detecting watershed-scale population trends associated with juvenile bull trout (Salvelinus confluentus) distributions. Electrofishing surveys were conducted across 275 stream sites from the Prairie Creek watershed, Northwest Territories, Canada. Site-level detectability of juvenile bull trout was not uniform, and imperfect detection affected modelled occupancy probabilities most in fringe habitats near distributional boundaries in steep reaches and large streams. We show that detecting a 30% change in watershed-level occupancy ≥78% of the time, as conservation guidelines suggest, may require three repeat surveys (i.e., temporal replicates) and increased spatial sampling intensity of fringe habitats. Additional sampling effort in fringe sites could be offset by sampling fewer sites in core habitats to optimize designs for detecting demographic shifts in bull trout, while still minimizing risk of nondetection for this cryptic species. |
format |
Article in Journal/Newspaper |
author |
Mochnacz, Neil J. MacKenzie, Darryl I. Koper, Nicola Docker, Margaret F. Isaak, Dan J. |
spellingShingle |
Mochnacz, Neil J. MacKenzie, Darryl I. Koper, Nicola Docker, Margaret F. Isaak, Dan J. Fringe effects: detecting bull trout ( Salvelinus confluentus) at distributional boundaries in a montane watershed |
author_facet |
Mochnacz, Neil J. MacKenzie, Darryl I. Koper, Nicola Docker, Margaret F. Isaak, Dan J. |
author_sort |
Mochnacz, Neil J. |
title |
Fringe effects: detecting bull trout ( Salvelinus confluentus) at distributional boundaries in a montane watershed |
title_short |
Fringe effects: detecting bull trout ( Salvelinus confluentus) at distributional boundaries in a montane watershed |
title_full |
Fringe effects: detecting bull trout ( Salvelinus confluentus) at distributional boundaries in a montane watershed |
title_fullStr |
Fringe effects: detecting bull trout ( Salvelinus confluentus) at distributional boundaries in a montane watershed |
title_full_unstemmed |
Fringe effects: detecting bull trout ( Salvelinus confluentus) at distributional boundaries in a montane watershed |
title_sort |
fringe effects: detecting bull trout ( salvelinus confluentus) at distributional boundaries in a montane watershed |
publisher |
Canadian Science Publishing |
publishDate |
2021 |
url |
http://dx.doi.org/10.1139/cjfas-2020-0219 https://cdnsciencepub.com/doi/full-xml/10.1139/cjfas-2020-0219 https://cdnsciencepub.com/doi/pdf/10.1139/cjfas-2020-0219 |
genre |
Northwest Territories |
genre_facet |
Northwest Territories |
op_source |
Canadian Journal of Fisheries and Aquatic Sciences volume 78, issue 8, page 1030-1044 ISSN 0706-652X 1205-7533 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/cjfas-2020-0219 |
container_title |
Canadian Journal of Fisheries and Aquatic Sciences |
_version_ |
1810467138948825088 |