Seed germination and dispersal of Eleocharis acuta and Eleocharis sphacelata under experimental hydrological conditions
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Seed germination and dispersal of Eleocharis acuta and Eleocharis sphacelata under experimental hydrological conditions William Higgisson
. Fiona Dyer
Received: 15 August 2020 / Accepted: 20 October 2020 Ó Springer Nature B.V. 2020
Abstract The occurrence and distribution of aquatic macrophytes within a wetland depends on the hydrological requirements of each species and the hydrological conditions. The aims of this study were to: (1) determine relationships between germination of Eleocharis acuta and Eleocharis sphacelata and hydrological regime, (2) determine the buoyancy of the seeds of E. acuta and E. sphacelata and hence their ability to disperse by hydrochory and (3) determine whether E. acuta and E. sphacelata exhibit dormancy. The seeds of E. acuta and E. sphacelata both germinated best on soil-soaked and when inundated for 80 days (to a depth of 5 cm). No seeds of either species germinated under rainfall conditions. Viability testing following the experiment showed that some seeds of both species remained ungerminated and viable following soaking, inundation and rainfall conditions for 90 days, demonstrating that E. acuta and E. sphacelata exhibit dormancy. At least 50% of E. acuta seeds floated for 32 days, while 50% of E. sphacelata seeds remained floating for at least 39 days. These germination and dispersal characteristics define where and when these Eleocharis species
Handling Editor: Te´lesphore Sime-Ngando. W. Higgisson (&) F. Dyer Centre for Applied Water Science, University of Canberra, University Drive, Bruce, Canberra, ACT 2617, Australia e-mail: [email protected]
establish related to temporal and spatial hydrological variability. Keywords Flood duration Wetland Macrophyte germination Dispersal
Introduction Wetlands are one of the most biologically productive ecosystems on earth, providing a range of ecosystem services at local and regional scales, and supporting high levels of biological diversity (Finlayson et al. 2005; Desta et al. 2012). Aquatic macrophytes are an important component of wetlands, providing habitat, trapping and processing sediment and nutrients, and maintaining water quality (Tanner 1996; Zierholz et al. 2001). Wetlands are also among the most threatened ecosystems on earth with substantial global losses in wetland areas occurring over the past century (Brinson and Malva´rez 2002; Davidson 2014; Dixon et al. 2016). Factors responsible for the loss and degradation of wetlands include diversions and damming of river flows causing disconnection of floodplain wetlands, cattle grazing and trampling, eutrophication, and the practices of filing, dyking and draining (Brinson and Malva´rez 2002; Finlayson et al. 2005; Zedler and Kercher 2005; Dudgeon et al. 2006). Water resource
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Aquat Ecol
development, i.e. river regulation and extraction of water for irrigation and other purposes, and other agricultural activities are two of the major drivers of wetland degradation and loss with changes to the frequenc
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