title: Seed dormancy and persistent sediment seed banks of ephemeral freshwater rock pools in the Australian monsoon tropics.
abstract: OBJECTIVE
  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.
  
  
  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.
authors: School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Perth, Australia, Kings Park and Botanic Garden, Fraser Avenue, West Perth WA 6005, Perth, Australia and Department of Biology, University of Kentucky, Lexington, KY 40506, USA School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Perth, Australia, Kings Park and Botanic Garden, Fraser Avenue, West Perth WA 6005, Perth, Australia and Department of Biology, University of Kentucky, Lexington, KY 40506, USA Adam.Cross@bgpa.wa.gov.au.
authors: Adam T
authors: AT
authors: Cross
authors: School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Perth, Australia, Kings Park and Botanic Garden, Fraser Avenue, West Perth WA 6005, Perth, Australia and Department of Biology, University of Kentucky, Lexington, KY 40506, USA School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Perth, Australia, Kings Park and Botanic Garden, Fraser Avenue, West Perth WA 6005, Perth, Australia and Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
authors: Shane R
authors: SR
authors: Turner
authors: School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Perth, Australia, Kings Park and Botanic Garden, Fraser Avenue, West Perth WA 6005, Perth, Australia and Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
authors: Michael
authors: M
authors: Renton
authors: School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Perth, Australia, Kings Park and Botanic Garden, Fraser Avenue, West Perth WA 6005, Perth, Australia and Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
authors: Jerry M
authors: JM
authors: Baskin
authors: School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Perth, Australia, Kings Park and Botanic Garden, Fraser Avenue, West Perth WA 6005, Perth, Australia and Department of Biology, University of Kentucky, Lexington, KY 40506, USA School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Perth, Australia, Kings Park and Botanic Garden, Fraser Avenue, West Perth WA 6005, Perth, Australia and Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
authors: Kingsley W
authors: KW
authors: Dixon
authors: School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Perth, Australia, Kings Park and Botanic Garden, Fraser Avenue, West Perth WA 6005, Perth, Australia and Department of Biology, University of Kentucky, Lexington, KY 40506, USA School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Perth, Australia, Kings Park and Botanic Garden, Fraser Avenue, West Perth WA 6005, Perth, Australia and Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
authors: David J
authors: DJ
authors: Merritt
mesh_terms: D017753:Ecosystem; D004777:Environment; D005030:Ethylenes / Q000494:pharmacology; D005618:Fresh Water; D005663:Furans / Q000494:pharmacology; D019015:Geologic Sediments; D018525:Germination / Q000187:drug effects; D005875:Gibberellins / Q000494:pharmacology; D008027:Light; D019684:Magnoliopsida / Q000187:drug effects / Q000502:physiology*; D057445:Plant Dormancy; D010937:Plant Growth Regulators / Q000494:pharmacology; D011714:Pyrans / Q000494:pharmacology; D012621:Seasons; D036226:Seedlings / Q000187:drug effects / Q000502:physiology; D012639:Seeds / Q000187:drug effects / Q000502:physiology*; D013696:Temperature; D014329:Tropical Climate; D014904:Western Australia
chemical_list: D005030:Ethylenes; D005663:Furans; D005875:Gibberellins; D010937:Plant Growth Regulators; D011714:Pyrans; C557869:karrikinolide; C036216:ethylene; C007842:gibberellic acid
keywords: Ephemeral freshwater wetland; ethylene; hydrophytes; sandstone rock pools; sediment seed bank; seed dormancy; seed germination; seedling emergence patterns