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Propagule pressure does not consistently predict the outcomes of exotic bird introductions

Some have argued that the role of propagule pressure in explaining the outcomes of bird introductions is well-supported by the historical record. Here, we show that the data from a large published database (including 832 records with propagule information) do not support the conclusion that propagul...

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Autores principales: Moulton, Michael P., Cropper, Wendell P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: PeerJ Inc. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6744947/
https://www.ncbi.nlm.nih.gov/pubmed/31565569
http://dx.doi.org/10.7717/peerj.7637
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author Moulton, Michael P.
Cropper, Wendell P.
author_facet Moulton, Michael P.
Cropper, Wendell P.
author_sort Moulton, Michael P.
collection PubMed
description Some have argued that the role of propagule pressure in explaining the outcomes of bird introductions is well-supported by the historical record. Here, we show that the data from a large published database (including 832 records with propagule information) do not support the conclusion that propagule pressure is the primary determinant of introduction success in birds. A few compendia of historical reports have been widely used to evaluate introduction success, typically by combining data from numerous species and introduction locations. Very few taxa, other than birds, have usable spatially explicit records of introductions over time. This availability of data inflates the perceived importance of bird analyses for addressing factors related to invasion success. The available data allow limited testing of taxonomic and site-level factors of introduction outcomes. We did find significant differences in effort and success probabilities among avian orders and across highly aggregated spatial regions. As a test of a standard and logical expectation of the propagule pressure hypothesis, we concentrated on introductions with the smallest propagules, because it is for these the hypothesis is most likely to be correct. We analyzed the effect of numbers released in small propagules (two through 10) for 227 releases. Weighted linear regression indicated no significant effect of propagule size for this range of release size. In fact, the mean success rate of 28% for propagules of 2–10 isn’t significantly different than that of 34% for propagules of 11–100. Following the example of previous analyses, we expanded the statistical test of propagule pressure to include the full range of release numbers. No significant support for the propagule pressure hypothesis was found using logistic regression with either logit or complementary log-log link functions.
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spelling pubmed-67449472019-09-27 Propagule pressure does not consistently predict the outcomes of exotic bird introductions Moulton, Michael P. Cropper, Wendell P. PeerJ Biodiversity Some have argued that the role of propagule pressure in explaining the outcomes of bird introductions is well-supported by the historical record. Here, we show that the data from a large published database (including 832 records with propagule information) do not support the conclusion that propagule pressure is the primary determinant of introduction success in birds. A few compendia of historical reports have been widely used to evaluate introduction success, typically by combining data from numerous species and introduction locations. Very few taxa, other than birds, have usable spatially explicit records of introductions over time. This availability of data inflates the perceived importance of bird analyses for addressing factors related to invasion success. The available data allow limited testing of taxonomic and site-level factors of introduction outcomes. We did find significant differences in effort and success probabilities among avian orders and across highly aggregated spatial regions. As a test of a standard and logical expectation of the propagule pressure hypothesis, we concentrated on introductions with the smallest propagules, because it is for these the hypothesis is most likely to be correct. We analyzed the effect of numbers released in small propagules (two through 10) for 227 releases. Weighted linear regression indicated no significant effect of propagule size for this range of release size. In fact, the mean success rate of 28% for propagules of 2–10 isn’t significantly different than that of 34% for propagules of 11–100. Following the example of previous analyses, we expanded the statistical test of propagule pressure to include the full range of release numbers. No significant support for the propagule pressure hypothesis was found using logistic regression with either logit or complementary log-log link functions. PeerJ Inc. 2019-09-11 /pmc/articles/PMC6744947/ /pubmed/31565569 http://dx.doi.org/10.7717/peerj.7637 Text en © 2019 Moulton and Cropper https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited.
spellingShingle Biodiversity
Moulton, Michael P.
Cropper, Wendell P.
Propagule pressure does not consistently predict the outcomes of exotic bird introductions
title Propagule pressure does not consistently predict the outcomes of exotic bird introductions
title_full Propagule pressure does not consistently predict the outcomes of exotic bird introductions
title_fullStr Propagule pressure does not consistently predict the outcomes of exotic bird introductions
title_full_unstemmed Propagule pressure does not consistently predict the outcomes of exotic bird introductions
title_short Propagule pressure does not consistently predict the outcomes of exotic bird introductions
title_sort propagule pressure does not consistently predict the outcomes of exotic bird introductions
topic Biodiversity
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6744947/
https://www.ncbi.nlm.nih.gov/pubmed/31565569
http://dx.doi.org/10.7717/peerj.7637
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