Seed dormancy and persistent sediment seed banks of ephemeral freshwater rock pools in the Australian monsoon tropics

Adam Cross, Shane Turner, Michael Renton, J.M. Baskin, Kingsley Dixon, David Merritt

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

© The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. Background and Aims: Rock pools are small, geologically stable freshwater ecosystems that are both hydrologically and biologically isolated. They harbour high levels of plant endemism and experience environmental unpredictability driven by the presence of water over variable temporal scales. This study examined the hypothesis that the sediment seed bank in monsoon tropical freshwater rock pools would persist through one or more periods of desiccation, with seed dormancy regulating germination timing in response to rock pool inundation and drying events. Methods: Seeds were collected from seven dominant rock pool species, and germination biology and seed dormancy were assessed under laboratory conditions in response to light, temperature and germination stimulators (gibberellic acid, karrikinolide and ethylene). Field surveys of seedling emergence from freshwater rock pools in the Kimberley region of Western Australia were undertaken, and sediment samples were collected from 41 vegetated rock pools. Seedling emergence and seed bank persistence in response to multiple wetting and drying cycles were determined. Key Results: The sediment seed bank of individual rock pools was large (13 824±307 to 218 320±42 412 seeds m-2 for the five species investigated) and spatially variable. Seedling density for these same species in the field ranged from 13 696 to 87 232 seedlings m-2. Seeds of rock pool taxa were physiologically dormant, with germination promoted by after-ripening and exposure to ethylene or karrikinolide. Patterns of seedling emergence varied between species and were finely tuned to seasonal temperature and moisture conditions, with the proportions of emergent seedlings differing between species through multiple inundation events. A viable seed bank persisted after ten consecutive laboratory inundation events, and seeds retained viability in dry sediments for at least 3 years. Conclusions: The persistent seed bank in freshwater rock pools is likely to provide resilience to plant communities against environmental stochasticity. Since rock pool communities are often comprised of highly specialized endemic and range-restricted species, sediment seed banks may represent significant drivers of species persistence and diversification in these ecosystems.
Original languageEnglish
Pages (from-to)847-859
JournalAnnals of Botany
Volume115
Issue number5
DOIs
Publication statusPublished - 2015

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seed dormancy
buried seeds
tropics
rocks
sediments
seedling emergence
germination
seeds
seedlings
ethylene
drying
after-ripening
desiccation (plant physiology)
gibberellic acid
Western Australia
plant communities
temperature
indigenous species
viability
Biological Sciences

Cite this

@article{278a3cf0b0164a2391fcb8f1183dcf4c,
title = "Seed dormancy and persistent sediment seed banks of ephemeral freshwater rock pools in the Australian monsoon tropics",
abstract = "{\circledC} The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. Background and Aims: Rock pools are small, geologically stable freshwater ecosystems that are both hydrologically and biologically isolated. They harbour high levels of plant endemism and experience environmental unpredictability driven by the presence of water over variable temporal scales. This study examined the hypothesis that the sediment seed bank in monsoon tropical freshwater rock pools would persist through one or more periods of desiccation, with seed dormancy regulating germination timing in response to rock pool inundation and drying events. Methods: Seeds were collected from seven dominant rock pool species, and germination biology and seed dormancy were assessed under laboratory conditions in response to light, temperature and germination stimulators (gibberellic acid, karrikinolide and ethylene). Field surveys of seedling emergence from freshwater rock pools in the Kimberley region of Western Australia were undertaken, and sediment samples were collected from 41 vegetated rock pools. Seedling emergence and seed bank persistence in response to multiple wetting and drying cycles were determined. Key Results: The sediment seed bank of individual rock pools was large (13 824±307 to 218 320±42 412 seeds m-2 for the five species investigated) and spatially variable. Seedling density for these same species in the field ranged from 13 696 to 87 232 seedlings m-2. Seeds of rock pool taxa were physiologically dormant, with germination promoted by after-ripening and exposure to ethylene or karrikinolide. Patterns of seedling emergence varied between species and were finely tuned to seasonal temperature and moisture conditions, with the proportions of emergent seedlings differing between species through multiple inundation events. A viable seed bank persisted after ten consecutive laboratory inundation events, and seeds retained viability in dry sediments for at least 3 years. Conclusions: The persistent seed bank in freshwater rock pools is likely to provide resilience to plant communities against environmental stochasticity. Since rock pool communities are often comprised of highly specialized endemic and range-restricted species, sediment seed banks may represent significant drivers of species persistence and diversification in these ecosystems.",
author = "Adam Cross and Shane Turner and Michael Renton and J.M. Baskin and Kingsley Dixon and David Merritt",
year = "2015",
doi = "10.1093/aob/mcv014",
language = "English",
volume = "115",
pages = "847--859",
journal = "Annals of Botany",
issn = "0305-7364",
publisher = "OXFORD UNIV PRESS UNITED KINGDOM",
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}

Seed dormancy and persistent sediment seed banks of ephemeral freshwater rock pools in the Australian monsoon tropics. / Cross, Adam; Turner, Shane; Renton, Michael; Baskin, J.M.; Dixon, Kingsley; Merritt, David.

In: Annals of Botany, Vol. 115, No. 5, 2015, p. 847-859.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Seed dormancy and persistent sediment seed banks of ephemeral freshwater rock pools in the Australian monsoon tropics

AU - Cross, Adam

AU - Turner, Shane

AU - Renton, Michael

AU - Baskin, J.M.

AU - Dixon, Kingsley

AU - Merritt, David

PY - 2015

Y1 - 2015

N2 - © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. Background and Aims: Rock pools are small, geologically stable freshwater ecosystems that are both hydrologically and biologically isolated. They harbour high levels of plant endemism and experience environmental unpredictability driven by the presence of water over variable temporal scales. This study examined the hypothesis that the sediment seed bank in monsoon tropical freshwater rock pools would persist through one or more periods of desiccation, with seed dormancy regulating germination timing in response to rock pool inundation and drying events. Methods: Seeds were collected from seven dominant rock pool species, and germination biology and seed dormancy were assessed under laboratory conditions in response to light, temperature and germination stimulators (gibberellic acid, karrikinolide and ethylene). Field surveys of seedling emergence from freshwater rock pools in the Kimberley region of Western Australia were undertaken, and sediment samples were collected from 41 vegetated rock pools. Seedling emergence and seed bank persistence in response to multiple wetting and drying cycles were determined. Key Results: The sediment seed bank of individual rock pools was large (13 824±307 to 218 320±42 412 seeds m-2 for the five species investigated) and spatially variable. Seedling density for these same species in the field ranged from 13 696 to 87 232 seedlings m-2. Seeds of rock pool taxa were physiologically dormant, with germination promoted by after-ripening and exposure to ethylene or karrikinolide. Patterns of seedling emergence varied between species and were finely tuned to seasonal temperature and moisture conditions, with the proportions of emergent seedlings differing between species through multiple inundation events. A viable seed bank persisted after ten consecutive laboratory inundation events, and seeds retained viability in dry sediments for at least 3 years. Conclusions: The persistent seed bank in freshwater rock pools is likely to provide resilience to plant communities against environmental stochasticity. Since rock pool communities are often comprised of highly specialized endemic and range-restricted species, sediment seed banks may represent significant drivers of species persistence and diversification in these ecosystems.

AB - © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. Background and Aims: Rock pools are small, geologically stable freshwater ecosystems that are both hydrologically and biologically isolated. They harbour high levels of plant endemism and experience environmental unpredictability driven by the presence of water over variable temporal scales. This study examined the hypothesis that the sediment seed bank in monsoon tropical freshwater rock pools would persist through one or more periods of desiccation, with seed dormancy regulating germination timing in response to rock pool inundation and drying events. Methods: Seeds were collected from seven dominant rock pool species, and germination biology and seed dormancy were assessed under laboratory conditions in response to light, temperature and germination stimulators (gibberellic acid, karrikinolide and ethylene). Field surveys of seedling emergence from freshwater rock pools in the Kimberley region of Western Australia were undertaken, and sediment samples were collected from 41 vegetated rock pools. Seedling emergence and seed bank persistence in response to multiple wetting and drying cycles were determined. Key Results: The sediment seed bank of individual rock pools was large (13 824±307 to 218 320±42 412 seeds m-2 for the five species investigated) and spatially variable. Seedling density for these same species in the field ranged from 13 696 to 87 232 seedlings m-2. Seeds of rock pool taxa were physiologically dormant, with germination promoted by after-ripening and exposure to ethylene or karrikinolide. Patterns of seedling emergence varied between species and were finely tuned to seasonal temperature and moisture conditions, with the proportions of emergent seedlings differing between species through multiple inundation events. A viable seed bank persisted after ten consecutive laboratory inundation events, and seeds retained viability in dry sediments for at least 3 years. Conclusions: The persistent seed bank in freshwater rock pools is likely to provide resilience to plant communities against environmental stochasticity. Since rock pool communities are often comprised of highly specialized endemic and range-restricted species, sediment seed banks may represent significant drivers of species persistence and diversification in these ecosystems.

U2 - 10.1093/aob/mcv014

DO - 10.1093/aob/mcv014

M3 - Article

VL - 115

SP - 847

EP - 859

JO - Annals of Botany

JF - Annals of Botany

SN - 0305-7364

IS - 5

ER -