Sampling designs matching species biology produce accurate and affordable abundance indices
Wildlife biologists often use grid-based designs to sample animals and generate abundance estimates. Although sampling in grids is theoretically sound, in application, the method can be logistically difficult and expensive when sampling elusive species inhabiting extensive areas. These factors make...
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ftpubmed:oai:pubmedcentral.nih.gov:3869179 2023-05-15T18:42:13+02:00 Sampling designs matching species biology produce accurate and affordable abundance indices Harris, Grant Farley, Sean Russell, Gareth J. Butler, Matthew J. Selinger, Jeff 2013-12-17 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3869179 https://doi.org/10.7717/peerj.227 en eng PeerJ Inc. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3869179 http://dx.doi.org/10.7717/peerj.227 © 2013 Harris et al. http://creativecommons.org/licenses/by/3.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. CC-BY Conservation Biology Text 2013 ftpubmed https://doi.org/10.7717/peerj.227 2014-01-05T02:05:06Z Wildlife biologists often use grid-based designs to sample animals and generate abundance estimates. Although sampling in grids is theoretically sound, in application, the method can be logistically difficult and expensive when sampling elusive species inhabiting extensive areas. These factors make it challenging to sample animals and meet the statistical assumption of all individuals having an equal probability of capture. Violating this assumption biases results. Does an alternative exist? Perhaps by sampling only where resources attract animals (i.e., targeted sampling), it would provide accurate abundance estimates more efficiently and affordably. However, biases from this approach would also arise if individuals have an unequal probability of capture, especially if some failed to visit the sampling area. Since most biological programs are resource limited, and acquiring abundance data drives many conservation and management applications, it becomes imperative to identify economical and informative sampling designs. Therefore, we evaluated abundance estimates generated from grid and targeted sampling designs using simulations based on geographic positioning system (GPS) data from 42 Alaskan brown bears (Ursus arctos). Migratory salmon drew brown bears from the wider landscape, concentrating them at anadromous streams. This provided a scenario for testing the targeted approach. Grid and targeted sampling varied by trap amount, location (traps placed randomly, systematically or by expert opinion), and traps stationary or moved between capture sessions. We began by identifying when to sample, and if bears had equal probability of capture. We compared abundance estimates against seven criteria: bias, precision, accuracy, effort, plus encounter rates, and probabilities of capture and recapture. One grid (49 km2 cells) and one targeted configuration provided the most accurate results. Both placed traps by expert opinion and moved traps between capture sessions, which raised capture probabilities. The grid design ... Text Ursus arctos PubMed Central (PMC) PeerJ 1 e227 |
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Conservation Biology Harris, Grant Farley, Sean Russell, Gareth J. Butler, Matthew J. Selinger, Jeff Sampling designs matching species biology produce accurate and affordable abundance indices |
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Conservation Biology |
description |
Wildlife biologists often use grid-based designs to sample animals and generate abundance estimates. Although sampling in grids is theoretically sound, in application, the method can be logistically difficult and expensive when sampling elusive species inhabiting extensive areas. These factors make it challenging to sample animals and meet the statistical assumption of all individuals having an equal probability of capture. Violating this assumption biases results. Does an alternative exist? Perhaps by sampling only where resources attract animals (i.e., targeted sampling), it would provide accurate abundance estimates more efficiently and affordably. However, biases from this approach would also arise if individuals have an unequal probability of capture, especially if some failed to visit the sampling area. Since most biological programs are resource limited, and acquiring abundance data drives many conservation and management applications, it becomes imperative to identify economical and informative sampling designs. Therefore, we evaluated abundance estimates generated from grid and targeted sampling designs using simulations based on geographic positioning system (GPS) data from 42 Alaskan brown bears (Ursus arctos). Migratory salmon drew brown bears from the wider landscape, concentrating them at anadromous streams. This provided a scenario for testing the targeted approach. Grid and targeted sampling varied by trap amount, location (traps placed randomly, systematically or by expert opinion), and traps stationary or moved between capture sessions. We began by identifying when to sample, and if bears had equal probability of capture. We compared abundance estimates against seven criteria: bias, precision, accuracy, effort, plus encounter rates, and probabilities of capture and recapture. One grid (49 km2 cells) and one targeted configuration provided the most accurate results. Both placed traps by expert opinion and moved traps between capture sessions, which raised capture probabilities. The grid design ... |
format |
Text |
author |
Harris, Grant Farley, Sean Russell, Gareth J. Butler, Matthew J. Selinger, Jeff |
author_facet |
Harris, Grant Farley, Sean Russell, Gareth J. Butler, Matthew J. Selinger, Jeff |
author_sort |
Harris, Grant |
title |
Sampling designs matching species biology produce accurate and affordable abundance indices |
title_short |
Sampling designs matching species biology produce accurate and affordable abundance indices |
title_full |
Sampling designs matching species biology produce accurate and affordable abundance indices |
title_fullStr |
Sampling designs matching species biology produce accurate and affordable abundance indices |
title_full_unstemmed |
Sampling designs matching species biology produce accurate and affordable abundance indices |
title_sort |
sampling designs matching species biology produce accurate and affordable abundance indices |
publisher |
PeerJ Inc. |
publishDate |
2013 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3869179 https://doi.org/10.7717/peerj.227 |
genre |
Ursus arctos |
genre_facet |
Ursus arctos |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3869179 http://dx.doi.org/10.7717/peerj.227 |
op_rights |
© 2013 Harris et al. http://creativecommons.org/licenses/by/3.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
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CC-BY |
op_doi |
https://doi.org/10.7717/peerj.227 |
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e227 |
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