Document ID: chunk:federal_register_of_legislation:F2024L00346:reg:3:p3
Version: federal_register_of_legislation:F2024L00346
Segment Type: reg
Provision Reference: reg 3 (pt 3/10)
Character Range: 32079–35081

of seeds per stem, is generally dependent on temperature and rainfall. Rainfall was relatively high in 2010, effectively ending a 13-year period of drought, and this was reflected in a lower seed fecundity across Spiny Rice-flower female individuals on the Victoria Volcanic Plains (4–32 seeds per stem in 2010 compared to 15–247 seeds per stem in 2009; Reynolds 2013). Plants are likely to have suffered from pollination limitation due to lower rates of insect pollinator activity during such a wet year.
Seed viability, an indication of maternal plant's ability to access resources, is improved by frequent biomass reduction (for example through burning) of the surrounding vegetation (Reynolds 2013). Spiny Rice-flower seeds possess a 'non-deep physiological dormancy' sensu Baskin & Baskin (2004). A period of dry storage followed by at least a month of cold stratification was found to alleviate seed dormancy (Reynolds 2013). Seed germination also positively responds to stimulation by gibberellic acid. Spiny Rice-flower germination follows a staggered germination syndrome (germination is not synchronous, and thus seedlings are produced as different multiple cohorts over time), even under optimal conditions (Reynolds 2013).
While the seed is oily and buoyant and can disperse via seasonal flood events, the seed has no obvious adaptation for long distance dispersal, and germinants (seedlings) commonly cluster close to female or bisexual plants (Foreman 2005, 2011; James & Jordan 2014). Circumstantial observations have found seedlings in a translocated soil plug even in the complete absence of the flowering plant or recent seed introduction. This implies that a persistent soil seed bank exists (Reynolds 2013). Regan et al. (2021) suggested that the Spiny Rice-flower seed bank can remain in the soil while maintaining its viability for approximately 6 years (Figure 5).
Given the continuing pressure on native species habitat and noting the lack of opportunities for successful in situ recruitment, ex situ seed conservation is a strategic approach to safeguard native plant species (Martyn Yenson et al. 2021) and would support the recovery of the Spiny Rice-flower when seed is actively used in restoration or translocation programs. In support of ex situ seed conservation, a seed collection protocol for Spiny Rice-flower has been developed by the Pimelea spinescens Recovery Team (2018). Further, noting that seed supply is key for Spiny Rice-flower translocations as well as grassland habitat restoration, further research should include aspects of securing and use of a genetically diverse seed supply.
Figure 4 Spiny Rice-flower hosts various invertebrate species, including insects that are important as its pollination vector.

Photo © Elspeth Swan (left) and Debbie Reynolds (right)

Recruitment in situ
The majority of Spiny Rice-flower populations consist of mainly mature individuals (McCaw 2014, 2020), which may indicate an obstacle to or failure of recruitment (Mueck