Document ID: chunk:federal_register_of_legislation:F2024L00346:reg:4:p2
Version: federal_register_of_legislation:F2024L00346
Segment Type: reg
Provision Reference: reg 4 (pt 2/7)
Character Range: 55479–58489

are small and unprotected.
Roadsides and rail reserves support some of the most important habitats of Spiny Rice-flower, particularly within the Natural Temperate Grasslands of the Victorian Volcanic Plain (Carland & Kennedy 2010). These populations are at great risk of individual loss from any maintenance works such as slashing, grading, clearing, herbicide application, road widening and soil compaction by vehicle movement (Carter & Walsh 2006; Foreman 2012). Incremental losses of individual plants, without replacement, can rapidly lead to extirpation especially for these small and often isolated populations (Ramalho et al. 2014). Spiny Rice-flower populations located along narrow linear road or rail reserves are also subject to high levels of edge effects and therefore have a greater probability of degradation over time (DSE 2008).
Reduced connectivity that limits gene-flow between sites is another major threat following on from habitat loss and fragmentation. Small populations can retain valuable genetic variation and remain biologically important if close enough to be connected by gene-flow. However, as the distance between populations is greater than its known pollinators' travel capacity, the genetic integrity of Spiny Rice-flower may be at risk of inbreeding depression (Markert et al. 2010; James & Jordan 2014).
Despite the improvement in our understanding of distribution and occurrence of Spiny Rice-flower, the statement in the initial advice from the Threatened Species Scientific Committee (TSSC 2003) to the then Minister is still applicable: "Based on the rate of decline of grassland habitat since the 1980s, it is estimated that the population size of Pimelea has declined by as much as 30% over the past 20 years". This conclusion is supported by a study in 2018 which revisited 14 sites which were first surveyed in 2009. The study found that eight of the 14 sites were decreasing in size with mature plants dying and seedlings rare (Reynolds 2019).

Habitat loss associated with land tenure
About 52% of the population (approximately 84% of total individuals; Appendix 1) are located within unreserved public land consisting of roadside and railway corridors which are subject to continuous pressures from traffic disturbances, compaction from vehicles, and management activities (slashing, mowing, runoff of toxicants). Approximately 20% is situated on private land, with 15% of the total population occurring within existing conservation reserves and 10% is in utility sites owned by Melbourne Water, Local Government and other agencies (Appendix 1). Several very large populations (>1,000 individuals each) occur on private properties where the tenure is unsecured, and on other public land not reserved for conservation (Carter & Walsh 2006; Foreman 2012; TSSC 2016; Appendix 1). Regardless the tenure types, the majority of sites support extremely low numbers of individuals (< 10 plants) that are unlikely to survive without intensive management intervention such