Optimal sampling methods for modelling the occupancy of Arctic Grayling (Thymallus arcticus) in the Canadian Barrenlands
In occupancy models, imperfect detectability of animals is usually corrected for by using temporally-repeated surveys to estimate probability of detection. Substituting spatial replicates for temporal replicates could be an advantageous sampling strategy in remote Arctic regions, but may lead to ser...
| Main Authors: | , , |
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| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
NRC Research Press (a division of Canadian Science Publishing)
2016
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| Subjects: | |
| Online Access: | http://hdl.handle.net/1807/77658 http://www.nrcresearchpress.com/doi/abs/10.1139/cjfas-2016-0429 |
| Summary: | In occupancy models, imperfect detectability of animals is usually corrected for by using temporally-repeated surveys to estimate probability of detection. Substituting spatial replicates for temporal replicates could be an advantageous sampling strategy in remote Arctic regions, but may lead to serious violations of model assumptions. Using a case study of site occupancy of adfluvial young-of-year Arctic Grayling in Barrenland tundra streams, we assessed reliability and efficiency of alternative sampling strategies; i) randomly distributed vs sequential adjacent spatial replicates; ii) visual vs electrofishing surveys; and, iii) spatial vs temporal replicates. Sequential, adjacent spatial replicates produced spatially auto-correlated data. Autocorrelation was relieved using randomly distributed spatial replicates, but using these randomly distributed spatial replicates introduced significant error into estimates of the probability of occupancy in streams. Models designed for spatially-autocorrelated data could minimize this bias. Visual and electrofishing surveys produced comparable probabilities of detection. Spatially-replicated surveys performed better than temporal replicates. The easiest and relatively most cost-effective sampling methods performed as well as, or better than, the more established, expensive, and logistically difficult alternatives for occupancy estimation. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author. |
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