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Seed viability and germination success of Acacia tortilis along land‐use and aridity gradients in the Eastern Sahara

Our study focuses on the keystone species Acacia tortilis and is the first to investigate the effect of domestic ungulates and aridity on seed viability and germination over an extensive part of the Eastern Sahara. Bruchids infest its seeds and reduce their viability and germination, but ingestion b...

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Autores principales: Andersen, Gidske Leknæs, Krzywinski, Knut, Gjessing, Håkon K., Pierce, Richard Holton
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4716523/
https://www.ncbi.nlm.nih.gov/pubmed/26811790
http://dx.doi.org/10.1002/ece3.1851
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author Andersen, Gidske Leknæs
Krzywinski, Knut
Gjessing, Håkon K.
Pierce, Richard Holton
author_facet Andersen, Gidske Leknæs
Krzywinski, Knut
Gjessing, Håkon K.
Pierce, Richard Holton
author_sort Andersen, Gidske Leknæs
collection PubMed
description Our study focuses on the keystone species Acacia tortilis and is the first to investigate the effect of domestic ungulates and aridity on seed viability and germination over an extensive part of the Eastern Sahara. Bruchids infest its seeds and reduce their viability and germination, but ingestion by ruminant herbivores diminishes infestation levels and enhances/promotes seed viability and germination. The degree of these effects seems to be correlated with animal body mass. Significantly reduced numbers of wild ruminant ungulates have increased the potential importance of domestic animals and pastoral nomadism for the functionality of arid North African and Middle Eastern ecosystems. We sampled seeds (16,543) from A. tortilis in eight areas in three regions with different aridity and land use. We tested the effect of geography and sampling context on seed infestation using random effects logistic regressions. We did a randomized and balanced germination experiment including 1193 seeds, treated with different manure. Germination time and rates across geography, sampling context, and infestation status were analyzed using time‐to‐event analyses, Kaplan–Meier curves and proportional hazards Cox regressions. Bruchid infestation is very high (80%), and the effects of context are significant. Neither partial infestation nor adding manure had a positive effect on germination. There is a strong indication that intact, uningested seeds from acacia populations in the extremely arid Western Desert germinate more slowly and have a higher fraction of hard seeds than in the Eastern Desert and the Red Sea Hills. For ingested seeds in the pastoralist areas we find that intact seeds from goat dung germinate significantly better than those from camel dung. This is contrary to the expected body‐mass effect. There is no effect of site or variation in tribal management.
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spelling pubmed-47165232016-01-25 Seed viability and germination success of Acacia tortilis along land‐use and aridity gradients in the Eastern Sahara Andersen, Gidske Leknæs Krzywinski, Knut Gjessing, Håkon K. Pierce, Richard Holton Ecol Evol Original Research Our study focuses on the keystone species Acacia tortilis and is the first to investigate the effect of domestic ungulates and aridity on seed viability and germination over an extensive part of the Eastern Sahara. Bruchids infest its seeds and reduce their viability and germination, but ingestion by ruminant herbivores diminishes infestation levels and enhances/promotes seed viability and germination. The degree of these effects seems to be correlated with animal body mass. Significantly reduced numbers of wild ruminant ungulates have increased the potential importance of domestic animals and pastoral nomadism for the functionality of arid North African and Middle Eastern ecosystems. We sampled seeds (16,543) from A. tortilis in eight areas in three regions with different aridity and land use. We tested the effect of geography and sampling context on seed infestation using random effects logistic regressions. We did a randomized and balanced germination experiment including 1193 seeds, treated with different manure. Germination time and rates across geography, sampling context, and infestation status were analyzed using time‐to‐event analyses, Kaplan–Meier curves and proportional hazards Cox regressions. Bruchid infestation is very high (80%), and the effects of context are significant. Neither partial infestation nor adding manure had a positive effect on germination. There is a strong indication that intact, uningested seeds from acacia populations in the extremely arid Western Desert germinate more slowly and have a higher fraction of hard seeds than in the Eastern Desert and the Red Sea Hills. For ingested seeds in the pastoralist areas we find that intact seeds from goat dung germinate significantly better than those from camel dung. This is contrary to the expected body‐mass effect. There is no effect of site or variation in tribal management. John Wiley and Sons Inc. 2015-12-29 /pmc/articles/PMC4716523/ /pubmed/26811790 http://dx.doi.org/10.1002/ece3.1851 Text en © 2015 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution (http://creativecommons.org/licenses/by/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Research
Andersen, Gidske Leknæs
Krzywinski, Knut
Gjessing, Håkon K.
Pierce, Richard Holton
Seed viability and germination success of Acacia tortilis along land‐use and aridity gradients in the Eastern Sahara
title Seed viability and germination success of Acacia tortilis along land‐use and aridity gradients in the Eastern Sahara
title_full Seed viability and germination success of Acacia tortilis along land‐use and aridity gradients in the Eastern Sahara
title_fullStr Seed viability and germination success of Acacia tortilis along land‐use and aridity gradients in the Eastern Sahara
title_full_unstemmed Seed viability and germination success of Acacia tortilis along land‐use and aridity gradients in the Eastern Sahara
title_short Seed viability and germination success of Acacia tortilis along land‐use and aridity gradients in the Eastern Sahara
title_sort seed viability and germination success of acacia tortilis along land‐use and aridity gradients in the eastern sahara
topic Original Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4716523/
https://www.ncbi.nlm.nih.gov/pubmed/26811790
http://dx.doi.org/10.1002/ece3.1851
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