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Regulation of open populations of a stream insect through larval density dependence

1. In organisms with complex life cycles, the various stages occupy different habitats creating demographically open populations. The dynamics of these populations will depend on the occurrence and timing of stochastic influences relative to demographic density dependence, but understanding of these...

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Autores principales: McIntosh, Angus R., Greig, Hamish S., Howard, Simon
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9541859/
https://www.ncbi.nlm.nih.gov/pubmed/35362147
http://dx.doi.org/10.1111/1365-2656.13696
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author McIntosh, Angus R.
Greig, Hamish S.
Howard, Simon
author_facet McIntosh, Angus R.
Greig, Hamish S.
Howard, Simon
author_sort McIntosh, Angus R.
collection PubMed
description 1. In organisms with complex life cycles, the various stages occupy different habitats creating demographically open populations. The dynamics of these populations will depend on the occurrence and timing of stochastic influences relative to demographic density dependence, but understanding of these fundamentals, especially in the face of climate warming, has been hampered by the difficulty of empirical studies. 2. Using a logically feasible organism, we conducted a replicated density‐perturbation experiment to manipulate late‐instar larvae of nine populations of a stream caddisfly, Zelandopsyche ingens, and measured the resulting abundance over 2 years covering the complete life cycle of one cohort to evaluate influences on dynamics. 3. Negative density feedback occurred in the larval stage, and was sufficiently strong to counteract variation in abundance due to manipulation of larval density, adult caddis dispersal in the terrestrial environment as well as downstream drift of newly hatched and older larvae in the current. This supports theory indicating regulation of open populations must involve density dependence in local populations sufficient to offset variability associated with dispersal, especially during recruitment, and pinpoints the occurrence to late in the larval life cycle and driven by food resource abundance. 4. There were large variations in adult, egg mass and early instar abundance that were not related to abundance in the previous stage, or the manipulation, pointing to large stochastic influences. Thus, the results also highlight the complementary nature of stochastic and deterministic influences on open populations. Such density dependence will enhance population persistence in situations where variable dispersal and transitioning between life stages frequently creates mismatches between abundance and the local availability of resources, such as might become more common with climate warming.
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spelling pubmed-95418592022-10-14 Regulation of open populations of a stream insect through larval density dependence McIntosh, Angus R. Greig, Hamish S. Howard, Simon J Anim Ecol Research Articles 1. In organisms with complex life cycles, the various stages occupy different habitats creating demographically open populations. The dynamics of these populations will depend on the occurrence and timing of stochastic influences relative to demographic density dependence, but understanding of these fundamentals, especially in the face of climate warming, has been hampered by the difficulty of empirical studies. 2. Using a logically feasible organism, we conducted a replicated density‐perturbation experiment to manipulate late‐instar larvae of nine populations of a stream caddisfly, Zelandopsyche ingens, and measured the resulting abundance over 2 years covering the complete life cycle of one cohort to evaluate influences on dynamics. 3. Negative density feedback occurred in the larval stage, and was sufficiently strong to counteract variation in abundance due to manipulation of larval density, adult caddis dispersal in the terrestrial environment as well as downstream drift of newly hatched and older larvae in the current. This supports theory indicating regulation of open populations must involve density dependence in local populations sufficient to offset variability associated with dispersal, especially during recruitment, and pinpoints the occurrence to late in the larval life cycle and driven by food resource abundance. 4. There were large variations in adult, egg mass and early instar abundance that were not related to abundance in the previous stage, or the manipulation, pointing to large stochastic influences. Thus, the results also highlight the complementary nature of stochastic and deterministic influences on open populations. Such density dependence will enhance population persistence in situations where variable dispersal and transitioning between life stages frequently creates mismatches between abundance and the local availability of resources, such as might become more common with climate warming. John Wiley and Sons Inc. 2022-04-09 2022-08 /pmc/articles/PMC9541859/ /pubmed/35362147 http://dx.doi.org/10.1111/1365-2656.13696 Text en © 2022 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society. https://creativecommons.org/licenses/by-nc-nd/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc-nd/4.0/ (https://creativecommons.org/licenses/by-nc-nd/4.0/) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
spellingShingle Research Articles
McIntosh, Angus R.
Greig, Hamish S.
Howard, Simon
Regulation of open populations of a stream insect through larval density dependence
title Regulation of open populations of a stream insect through larval density dependence
title_full Regulation of open populations of a stream insect through larval density dependence
title_fullStr Regulation of open populations of a stream insect through larval density dependence
title_full_unstemmed Regulation of open populations of a stream insect through larval density dependence
title_short Regulation of open populations of a stream insect through larval density dependence
title_sort regulation of open populations of a stream insect through larval density dependence
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9541859/
https://www.ncbi.nlm.nih.gov/pubmed/35362147
http://dx.doi.org/10.1111/1365-2656.13696
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