THREATENED SPECIES SCIENTIFIC COMMITTEE Established under the Environment Protection and Biodiversity Conservation Act 1999

The Minister’s delegate approved this Conservation Advice on 16/12/2016.

Conservation Advice spinescens subsp. spinescens

spiny rice-flower

Conservation Status Pimelea spinescens subsp. spinescens (spiny rice-flower) is listed as Critically Endangered under the Environment Protection and Biodiversity Conservation Act 1999 (Cwlth) (EPBC Act) effective from 1 May 2003.

In Victoria it is listed as Endangered under the Advisory List of Rare or Threatened in Victoria 2014 , and Threatened under the Victorian Flora and Fauna Guarantee Act 1988.

The main factor that is the cause of the species being eligible for listing in the Critically Endangered category is a very restricted area of occupancy that is likely to continue to decline due to clearing for land development, habitat degradation due to invasive weeds, land management practices and lack of successful recruitment under these and projected future drier conditions.

Description Spiny rice-flower is a small spreading shrub growing to 50 cm in height. It has narrow, green, hairless, oval leaves 2 – 10 mm long and 1 – 3 mm wide, and older stems are often spine-tipped. Clusters of between 6 and 12 small, unisexual (rarely bisexual), hairless pale yellow flowers form the inflorescences. Flowers are 1.5 – 3 mm long (males slightly larger than females) and have four ovate petal-like lobes. Floral clusters are subtended by four leaf-like bracts 3 – 7 mm long and 1.5 – 4 mm wide.

Fruits are ovoid, approximately 3 mm long, 1-seeded, with a thin fleshy layer surrounding the oily seed (description from Walsh & Entwisle 1996). Plants from more northerly populations appear more robust than those from southern areas. Hairless flowers and stalks separate this subspecies from Pimelea spinescens subsp. pubiflora (Wimmera rice-flower) (Carter & Walsh 2006).

Distribution Spiny rice-flower is endemic to Victoria, where it occurs in the central west of the state (Walsh & Entwisle 1996); predominantly in the Victorian Volcanic Plain, Victorian Midlands and Riverina IBRA (Interim Biogeographic Regionalisation for Australia) Bioregions (DEH 2000). Based on entries in the spiny rice-flower state-wide database, approximately 88 000 plants are estimated to occur in 208 (and possibly up to 275) wild sites (Foreman 2012).

Historically, the species was undoubtedly much more widespread and abundant within the region where it currently occurs (Carter & Walsh 2006). Populations are now substantially fragmented and depleted due to land clearance for settlement, industry and agriculture. Many populations consist of a small number of plants (55 percent of sites with population counts have fewer than 100 plants), with most occurring in tiny patches of remnant habitat (59 percent of sites with extent estimates are smaller than 1ha) such as on roadsides and rail easements (Carter & Walsh 2006). However, the spiny rice-flower database includes many old and imprecise records and these figures are likely to be an overestimate of the actual situation. Some large populations occur on private property where grazing impacts are light (Recovery Team pers. comm., 2016).

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Life history The spiny rice-flower is slow-growing and may live up to 100 years (Mueck 2000). Most plants have either female or male flowers, but some have both or predominantly bisexual flowers (Foreman 2012; Reynolds 2013). Recruitment was previously thought to be low, with germination or seedling survival an irregular event (Mueck 2000) and most populations appearing to consist of relatively mature plants with little evidence of recruitment (Mueck 2000). However, since 2006 targeted monitoring (Cropper 2003, 2009; Foreman 2005, 2011) and research (Reynolds 2013) has found germination and recruitment to be widespread. A recruitment level (i.e. germinants surviving the first summer) of 14 percent was reported from sites within the Volcanic Plains (Reynolds 2013), which was likely associated with optimal climatic conditions (Foreman 2012).

Recruitment dynamics and requirements for successful in situ recruitment and persistence are not well understood (Foreman 2012), as not all seed will germinate even if conditions are optimal (Reynolds 2013). However, like most grassland species, the species is tolerant of fire and mature plants readily resprout after fire (Mueck 2000).

The species flowers from April to August (Entwisle 1996) and germinates from July to November (Foreman 2011; Reynolds 2013). Germination appears to be regulated partly by rainfall, with autumn drought and high rainfall both apparently preventing germination (Foreman 2011; Foreman 2012). Germinants are often found in areas close to female or bisexual plants, suggesting that dispersal distances are small (Foreman 2011). Genetic analysis of seed showed that most seed results from outcrossing via pollinators (James & Jordan 2014) but some seed appeared to result from selfing, indicating that there is a degree of self-compatibility in the breeding system. Mixed mating systems are common in species but outcrossing generally provides a greater level of genetic diversity, which is the basis for adaptation and should be a high priority for management.

Habitat Spiny rice-flower is predominantly associated with two threatened ecological communities: ° ‘Natural Temperate Grassland of the Victorian Volcanic Plain’ – listed as Critically Endangered under the EPBC Act (TSSC 2008). This community is also listed under the Flora and Fauna Guarantee Act 1988 (Vic) (FFG Act) as ‘Western (Basalt) Plains Grasslands’; and ° ‘Natural Grasslands of the Murray Valley Plains’ – listed as Critically Endangered under the EPBC Act (TSSC 2012), and listed as ‘Northern Plains Grasslands’ under the FFG Act (DSE 2003).

Spiny rice-flower has also been reported in association with Eucalyptus leucoxylon (yellow gum) and E. microcarpa (grey box) grassy woodland in the Goldfields (Foreman 2005), and Allocasuarina luehmannii (Buloke) open grassy woodland in the Wimmera (Deanna Marshall pers. comm., cited in Foreman 2012). It is likely these grassy woodland habitats represent ecological communities also listed under the EPBC Act.

The species occurs in grassland or open shrubland, usually developed on clay soils (Walsh & Entwisle 1996). Plants from more northerly populations occur on red clay complexes, while plants from southern populations occur on heavy grey-black clay loams derived from basalt. Topography is generally flat but populations may occur on slight rises or in slight depressions prone to temporary inundation. Vegetation is often dominated by Themeda triandra (kangaroo grass), with Austrostipa spp. (speargrass) or Rytidosperma spp. (wallaby grass) commonly associated. Co-occurring species often include Acaena echinata (sheep’s burr), Calocephalus citreus (lemon beauty-heads), Chrysocephalum apiculatum (common everlasting), Eryngium ovinum (blue devil), Plantago varia (variable plantain), Ptilotus erubescens (hairy tails),

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Schoenus apogon (common bog-sedge) and Velleia paradoxa (spur velleia) (Carter & Walsh 2006) .

Threats The primary threats to spiny rice-flower are land clearing and habitat degradation. Most of the populations are small and fragmented, and their long-term viability is doubtful without intensive site management. Reduced connectivity limits gene-flow between sites, and genetic integrity is at risk if inbreeding ocurrs as a result of distances between sites being greater than the travel distance of pollinators. Large populations can also experience significant declines over relatively short periods of time, especially following periods of drought (Foreman 2012).

Table 1 – Threats to the spiny rice-flower in approximate order of severity of risk, based on available evidence.

Threat Threat type and status Evidence base factor Habitat loss and fragmentation Changing known current Several very large populations occur on private land use - property potentially subject to changing land pasture use, such as from grazing to cropping, or from improvement farming to industrial and residential uses, that and could severely damage or destroy populations agricultural (Carter & Walsh 2006). Although this threat is intensification uneven across the species’ range, it remains a high risk where tenure is unsecured (Foreman 2012). Road and rail known current Many populations occur along roadsides and maintenance some rail reserves, and are at great risk from any maintenance works such as slashing, grading, clearing, herbicide application, widening and soil compaction by vehicle movement (Carter & Walsh 2006). Fire Prolonged known current Fire creates inter-tussock spaces which reduces lack of fire the abundance of annual exotic grasses, which can otherwise crowd out the spiny rice-flower (Foreman 2012). In the southern populations, it has been observed that the absence of disturbance from fire results in a rapid decline or cessation in recruitment, and population extirpation if sustained (Foreman 2012). The same process applies in the north, but at a slower rate, suggesting that controlled grazing can mimic some of the positive effects of fire (Foreman 2012).

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Invasive plants Weed known current Habitat degradation and competitive exclusion invasion from invasive plants threatens all populations, with the perennial introduced grasses bulbous canary-grass (Phalaris aquatica ), flax-leaf broom (Genista linifolia ) and tall wheatgrass (Lophopyrum ponticum ) the main threats (Foreman 2012). The risk is greatest in smaller, more isolated and heavily disturbed sites (Foreman 2012). Grazing Feral known current Most populations are threatened by feral herbivores herbivores including rabbits (Oryctolagus and livestock cuniculus ) and hares ( Lepus europaeus ), while populations on private land have the additional pressure of grazing by domestic stock (Carter & Walsh 2006). Rabbit exclusion fencing (along with other measures) has been very effective at relatively small sites (Lake Borrie, near Werribee [Cropper 2009]). In the north, light grazing regimes (low stocking levels and rotational systems) appear to be beneficial to the conservation of the spiny rice-flower by maintaining an open habitat structure and by reducing competition from weeds (Foreman 2012).

Conservation Actions

There is an existing Pimelea spinescens Recovery Team which has overseen implementation of the National Recovey Plan for the Spiny Rice-flower Pimelea spinescens subsp. spinescens (Carter & Walsh 2006). The recovery team was established in 2005 and comprises representatives from the Victorian state government, Royal Botanic Gardens Melbourne, environmental consultants, and academic research institutions (Foreman 2012).

The Pimelea Conservation Trust Fund was established in 2005 as part of a Conservation Agreement with a developer in relation to the protection and conservation of the spiny rice-flower. A Trust Committee has been established, with representatives from Federal, State and Local governments to administer the funds in accordance with the Conservation Agreement, with Trust for Nature acting as Trustee for the fund (Trust for Nature, 2014). The Fund supports various conservation projects that benefit the spiny rice-flower, including: • The management of two protected areas - Altona Nature Conservation Reserve and Pimelea Nature Conservation Reserve. • An examination of the species’ genetic diversity and population structure by the Royal Botanical Gardens. This is helping to optimise conservation activities by maintaining genetic diversity to help and ensure its long-term survival. • An assessment of all the spiny rice-flower translocations that have been carried out to date (Biosis, 2014). This has highlighted ways to improve future translocation activities. • The development of a spiny rice-flower monitoring protocol.

Effective site management can improve the size of populations − for example at Lake Borrie, numbers of the spiny rice-flower increased by 33 percent between 2006 and 2008 following the virtual elimination of rabbits by fencing, weed eradication by spot spraying and the introduction of

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routine burning (Cropper 2009). Translocation is a last resort for conservation as a percentage of translocated plants are inevitably lost. Monitoring and optimal management practices have shown that translocated plants can survive for at least 12 years once established (Biosis 2014).

Conservation and Management priorities Habitat loss and fragmentation o Where viable, protect key populations from vegetation clearing and degradation (including an adequate proportion of sites on roadsides and rail easements) through the establishment of formal reserves and conservation agreements with landholders. o Install signs advising the public of the presence of a nationally Critically Endangered species and the importance of protecting it. Fire o Ensure that strategic planning for prescribed burning accounts for the needs of the spiny rice-flower in determining fire regimes, in order to support habitat, germination and growth of the spiny rice-flower. o Fire and land management authorities should use appropriate means (such as suitable maps and/or field markers) to avoid inadvertent mechanical or chemical damage to the habitat and individuals of the spiny rice-flower. Invasive plants o Undertake appropriate and ongoing weed control at key sites. o Control the spread of weeds by reducing disturbance, e.g. through reducing stock, vehicle or public access. Grazing o Control the impact of feral herbivores at key sites, particularly rabbits and hares, through exclusion fencing and/or caging plants. o If livestock grazing occurs in the area, ensure landowners/managers use a light grazing regime to allow germination and growth of seedlings, and manage total grazing pressure at important sites through exclusion fencing or other barriers. o Develop and implement a stock management plan for key sites on roadside verges, rail easements and travelling stock routes. Distribute this information to drovers and graziers in the area to increase awareness of the spiny rice-flowers’ requirements. Seed collection, propagation and other ex-situ recovery actions o Establish plants from cultivation in appropriate secure tenure areas such as secure reserves. o Establish seed orchards for the species to provide seed for future projects, augmentation of small populations and opportunities for research. o To manage the risk of losing genetic diversity, undertake appropriate seed collection and storage in appropriate institutions, such as the Victorian Conservation Seedbank, Royal Botanic Gardens Victoria, and determine viability of stored seed. Best practice seed storage guidelines and procedures should be adhered to, to maximise seed viability and germinability. A sensible goal would be to collect seeds from all natural populations, with an initial focus on large and outlying populations in order to most efficiently secure represenation of maximum genetic diversity.

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o Establish new populations in suitable habitat adjoining or near existing populations on secure land (reserves or covenanted properties), using the recommended translocation measures and genotypes deemed to be suitable for the area. Stakeholder Engagement

o Establish an ongoing incentive program for actively involved community groups to help support and improve site-based conservation management. o Provide information on the spiny rice-flower distribution, ecology and habitat to relevant land managers. o Establish responsibilities and protocols for ongoing update of spiny rice-flower records in the Victorian Biodiversity Atlas; disseminate the atlas to relevant landowners or managers to raise awareness and encourage reporting.

Survey and Monitoring priorities • Survey all known and potential habitat to better define the distribution, number, size and structure of populations. • Use the standard monitoring guidelines developed by the Pimelea spinescens Recovery Team across a range of representative sites, to determine long-term population trends (Reynolds 2014). • Monitor responses to recovery actions and the progress of recovery; assess the effectiveness of management actions and the need to adapt them if necessary.

Information and research priorities • Assess more precisely the ecological requirements relevant to the recruitment and persistence of the spiny rice-flower, by collecting floristic and environmental information that captures site history and describes community ecology, plant condition and function at known habitat. • Undertake a site prioritisation process (based on accurate and complete state-wide records) to identify key sites to target for on-ground management actions − this could include consideration of population size, area and viability; threat level; habitat condition; regional occurrence and connectivity; threatening processes and the potential for reservation or other management actions. • Determine the requirements for successful recruitment, including the mechanisms of dispersal, dormancy, soil seedbank dynamics, weather patterns and seed biology. • Evaluate current reproductive/regenerative status, seed bank status and longevity, fecundity and recruitment levels at key sites. • Undertake further analysis of genetic variability of seed from individuals across different sites, in order to quantify the level of outcrossing and to modify seed collection strategies for restoration and translocation if necessary. • Determine the breeding system and the effective contribution of functionally female and hermaphrodite individuals to standing seed crops. • Compare the genetic diversity of the soil seedbank with seed crops and reproductive individuals across populations.

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• Identify optimal fire regimes for reintroductions, regeneration (vegetative regrowth and/or seed germination), and response to other prevailing fire regimes.

References cited in the advice

Biosis (2014). Review of Spiny Rice-flower translocations in Victoria. Report for Pimelea spinescens Recovery Team. Authors: Westcott, V. & Mueck, S. Biosis Pty Ltd, Melbourne. Project no. 15814.

Carter, O. & Walsh, N. (2006). National Recovery Plan for the Spiny Rice-flower Pimelea spinescens subsp. spinescens . Department of Sustainability and Environment, Melbourne.

Cropper, S. (2003). The distribution of Pimelea spinescens ssp. spinescens (Spiny Rice-flower) on Lake Borrie Spit and a discussion on the appropriate management of the population. Report prepared for Melbourne Water by Botanicus Australia Pty Ltd., Sunshine.

Cropper, S. (2009). Monitoring of Pimelea spinescens ssp. spinescens (Spiny Rice-flower) on Lake Borrie Spit in 2008 and a discussion on the appropriate management of the population. Report prepared for Melbourne Water by Botanicus Australia Pty Ltd., Sunshine.

Department of the Environment and Heritage (DEH) (2000). Revision of the Interim Biogeographic Regionalisation of Australia (IBRA) and the Development of Version 5.1. - Summary Report . Canberra.

Entwisle T. J. (1996) . In: Flora of Victoria, Vol. 3: Dicotyledons Winteraceae to Myrtaceae (eds N. G. Walsh & T. J. Entwisle), pp. 912–930. Inkata Press, Melbourne.

Foreman, P. W. (2005). Habitat condition and demographic structure of 16 populations from the Victorian Riverina and Volcanic Plains, Department of Sustainability and Environment, East Melbourne.

Foreman, P. W. (2011). Assessment of the Spiny Rice-flower populations at 16 sites on Victoria's northern and volcanic plains in 2004 and 2009. Unpublished Report, Blue Devil Consulting, Castlemaine.

Foreman, P. W. (2012). National Recovery Plan for the Spiny Rice-flower Pimelea spinescens Rye. subsp. spinescens . 2012 to 2016. Report prepared by Blue Devil Consulting for the Department of Sustainability, Environment, Water, Population and Communities, Canberra.

Franklin, I. R. (1980). Evolutionary change in small populations. In: Conservation Biology: An Evolutionary-Ecological Perspective (eds E. Soulé & B. A. Wilcox), pp. 135-150. Sinauer, Sunderland, Massachusetts.

James, E. A. & Jordan, R. (2014). Limited structure and widespread diversity suggest potential buffers to genetic erosion in a threatened grassland shrub Pimelea spinescens (Thymelaeaceae). Conservation Genetics 15(2 ), 305-317.

Mueck, S. (2000). Translocation of Plains Rice-flower ( Pimelea spinescens subsp. spinescens ), Laverton, Victoria. Ecological Management & Restoration 1(2) , 111–116.

Reynolds, D. M. (2013). Factors affecting recruitment in populations of Spiny Rice-flower (Pimelea spinescens Rye subspecies spinescens ) in Victoria’s natural temperate grasslands: relationships with management practices, biological and ecological characteristics. PhD thesis, Victoria University. Available on the internet at: http://vuir.vu.edu.au/25922/ .

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Reynolds, D. (2014). Monitoring Protocol for Pimelea spinescens Version 1.2_01_2014. Prepared for the Pimelea spinescens Recovery Team, Trust for Nature, Melbourne. Available on the internet at: http://www.trustfornature.org.au/special-conservation- trusts/pimelea-conservation-trust-fund/ .

Shaffer, M. L. (1981). Minimum population sizes for species conservation. BioScience 31 , 131- 134.

Soulé, M. E. (1980). Thresholds for survival: maintaining fitness and evolutionary potential. In: Conservation Biology: An Evolutionary-Ecological Perspective (eds E. Soulé & B. A. Wilcox), pp. 151-170. Sinauer, Sunderland, Massachusetts.

Walsh, N.G. & Entwisle, T.J. (1996). Flora of Victoria Volume 3: Winteraceae to Myrtaceae . Inkata Press, Melbourne.

Other sources cited in the advice

DSE (2003). Flora and Fauna Guarantee Act (1988) Action Statement No. 132: Spiny Rice-flower (Pimelea spinescens subsp. spinescens ). Department of Sustainability and Environment, East Melbourne. Available on the internet at: http://www.dse.vic.gov.au/ .

Recovery Team (2016). Personal communication by email, 21 October 2016. Pimelea spinescens Recovery Team.

Trust for Nature (2014). Pimelea Conservation Trust Fund. Available on the internet at: http://www.trustfornature.org.au/special-conservation-trusts/pimelea-conservation-trust- fund/

TSSC (2008). Commonwealth Listing Advice on Natural Temperate Grassland of the Victorian Volcanic Plain. Threatened Species Scientific Committee, Department of the Environment, Water, Heritage and the Arts. Available on the internet at: http://www.environment.gov.au/sprat .

TSSC (2012). Commonwealth Conservation Advice on Natural Grasslands of the Murray Valley Plains.Threatened Species Scientific Committee, Department of the Environment, Water, Heritage and the Arts. Available on the internet at: http://www.environment.gov.au/sprat .

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