The Minister approved this conservation advice on 14 Oct 2015; and included this species in the Endangered category, effective from 22 Oct 2015.

Conservation Advice Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025)

A saltbush

Taxonomy Conventionally accepted as Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) Western Australian Herbarium (a saltbush).

Summary of assessment

Conservation status The highest category for which Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) is eligible to be listed is Endangered under Criterion 2 (B1, B2, (a) and (b)(i), (ii), (iv)). It is also eligible for listing as Vulnerable under Criterion 1 (A3 (c)). Species can be listed as threatened under state and territory legislation. For information on the listing status of this species under relevant state or territory legislation, see http://www.environment.gov.au/cgi-bin/sprat/public/sprat.pl

Reason for conservation assessment by the Threatened Species Scientific Committee This advice follows assessment of information originally provided by Western Australia as part of the process to systematically review species that are inconsistently listed under the EPBC Act and relevant state legislation.

Public Consultation Notice of the proposed amendment and a consultation document was made available for public comment for 37 business days between 24 November 2014 and 16 January 2015. Any comments received that were relevant to the survival of the species were considered by the Committee as part of the assessment process.

Species/Sub-species Information Description Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) is a subdioecious plant distinguished by its dome shaped habit and divaricate woody branches. Female plants have distinctive fan-like fruits (with or without appendages). The species is an erect, subdioecious (with separate female and male plants; however, many male plants also have scattered female flowers in the lower branches) perennial shrub 0.4–1 m high with divaricate woody branches. Branchlets scruffy with collapsed vesicular hairs, glabrescent. Leaves scattered along branches or in clusters; petiole absent or to 0.3 mm long; lamina broadly elliptic to ovate, 0.8–6.5 mm long, 0.9–3.2(–5.3) mm wide with a dense indumentum of collapsed vesicle hairs forming a fused uneven surface, margin entire or sinuate to shallowly dentate. Male flowers in small, terminal glomerules or short panicles 3–10 mm long, 2.9–4 mm wide; bracteoles (leaf-like structures) absent; perianth 5-lobed, lobes elliptic 1.5– 1.9 mm long, 0.6–0.9 mm wide, fused in the lower half, with a rounded apex; staminal filaments five, filaments 1–1.8 mm long, 0.2–0.3 mm wide, anthers oblong, 0.4 mm long, 0.45 mm wide, yellow, becoming reddish with age, pollen yellow. Female flowers solitary, borne in leaf axils; perianth absent; bracteoles 2, sessile or with a short stipe 0.8–0.9 mm long, valves obovate 1.5– 4.4 mm long, 0.9–3.7 mm wide, equal in length, fused for lower half to two-thirds, outer surface Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) (a saltbush) Conservation Advice Page 1 of 8 smooth or later developing finger-like appendages, apex sinuate to dentate; stigmas 2, filiform 0.6–1.5 mm long, minutely plumose. Fruiting bracteoles sessile or with a thickened base 0.9– 1.7 mm long, 0.7–1.8 mm mm long; valves broadly obovate to fan shaped 4.5–7 mm long, 4–7.4 mm wide, becoming hardened with a swollen, spongy outer layer; outer surface smooth or with finger-like appendages on both sides, apex broadly dentate. Seeds rounded to broadly ovate in outline, brown, unornamented 0.9–1.4 mm long, 1.0–1.4 mm wide. The two populations of Atriplex sp. (Yeelirrie Station) possess similar levels of genetic diversity, but exhibit a high level of genetic differentiation given their proximity (Clark et al. 2012; Shepherd et al., submitted).

Distribution During surveys for BHP Billiton’s Yeelirrie Uranium project, consultants from Western Botanical collected what was thought to be a new species of Atriplex. In September 2009 specimens were presented to the Western Australian Herbarium and Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) was recognised as being distinct. Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) has a highly restricted distribution limited to two populations on Yeelirrie Station, which is a pastoral lease located 72 km south of Wiluna in Western Australia. The larger of the two populations is situated near the boundary of Albion Downs Station (‘Area A’ in Clarke et al., 2012), while the smaller population is located c. 30 km to the northwest (‘Area B’ in Clarke et al., 2012). This species of saltbush is found only within a palaeovalley of the Yilgarn craton that contains significant near-surface uranium mineralisation that has potential for resource development (Clarke et al. 2012). The two populations – Area A and Area B show genetic differentiation and it is recommended they be managed as separate conservation units (Shepherd et al., submitted). In addition, although there is evidence of very limited gene flow between the two populations, the species appears to have limited dispersal potential because there is significant isolation-by-distance evident among subpopulations (separated by less than 5 km) of the Area A population (Clarke et al. 2012). In addition to the populations at Area A and Area B, a limited number of plants have naturally established on an old rehabilitation site on Yeelirrie Station. Western Botanical has undertaken regional surveys targeting six lake systems (Annean, Mason, Miranda, Nabberu, Noondie and Way) during late 2009 and early 2010 and undertook further surveys targeting seven lake systems in May 2010; however, no new populations of Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) were located. The regional surveys were focused on flora and vegetation communities of interest (including self-mulching clay depressions and clay flats within calcrete systems). Each lake system was assessed for species of conservation significance in areas that were first identified from a helicopter survey and then verified during on-ground vegetation mapping. Much of the area surveyed in each lake system was gypsum rather than calcrete and therefore did not support the same vegetation communities as Yeelirrie, even though pockets of the same species were observed. Although not specifically targeting Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025), a survey of calcrete vegetation within the Murchison endeavoured to investigate potential areas for the presence of the species. Eight calcrete areas were surveyed: Yeelirrie Station, Lake Way, Lake Mason, Lake Miranda, Lake Maitland, Lake Darlot, Cogla Downs / Yarrabubba / Pollele (this area contained calcrete between Lake Annean & Lake Mason) and Paroo Station (100 km west of Wiluna). No additional populations of Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) were found (Meissner, 2011).

Relevant Biology/Ecology Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) is a recently discovered species which has been recorded from only two locations on Yeelirrie Station. A total of approximately 275,000 individuals are estimated for the two locations, comprising approximately 190,700 individuals at Area A and approximately 84,500 individuals at Area B (Western Botanical, 2011) (note: estimates for the number of female and male plants within each population are not available). The number of individuals was estimated using 10x10 m quadrats and floristic mapping.

Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) (a saltbush) Conservation Advice Page 2 of 8 Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) is dioecious and the male and female reproductive organs are generally present on separate plants. As a consequence, population estimates must take into account the total number of female plants present, as this will impact the percentage of the population that may be able to produce seed. Atriplex, like other members of the family Chenopodiaceae, have small indistinct flowers and are wind pollinated. Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) also has separate male and female plants. These features strongly promote outcrossing, which would result in an increase in genetic diversity. However, the presence of some female fruits on male plants of Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) could indicate a level of self-fertilisation (i.e. inbreeding) is occurring. Many chenopods produce papery fruits and seeds that are often widely dispersed by wind or water. The fruits of Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) however, appear to be retained on old branches for long periods, possibly until branch death. Old grey fruits occur on the lower branches, while new fruits are maturing near the terminal branches. This is likely to limit the distance seeds are dispersed from maternal plants and in turn may limit gene flow across populations. Also, Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) appears to be restricted to a very specific habitat as it is apparently confined to self-mulching clays within one palaeo-channel. These old drainage channels are only approximately 30 km apart but it is unclear if the disjunct populations of Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) ever become interconnected during flood events. Overall the probability of gene dispersal between the two populations is likely to be low given the two populations show significant genetic differentiation based on both microsatellite (Clarke et al., 2012) and Amplified Fragment Length Polymorphisms (AFLPs) data (Shepherd et al., submitted). As Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) is predominantly dioecious it is likely both a male and female plant would be required to establish any new population. This coupled with the potential low seed dispersal and specific habitat requirements (having been recorded only associated with palaeo-channels on self-mulching clays over uranium deposits) may account for the limited number of recorded populations of this taxon. Many species within the family Chenopodiaceae are known to be polyploids (species with multiple sets of chromosomes). For example the widespread Atriplex nummularia is an octaploid, which has eight sets of chromosomes. Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) is a tetraploid (Shepherd et al., submitted). Like other polyploids it maintains high levels of intra-population genetic diversity, but the degree of genetic differentiation supports treatment of the two major Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) populations as distinct genetic entities and possibly subspecies (Clarke et al., 2012; Shepherd et al., submitted).

Threats Threat factor Threat Threat Evidence base Threat abatement type status Grazing by Suspected Current - Plants appear to have Destocking is proposed stock (Area A)/ been impacted by grazing and fencing around the past - however there is no Area A population has (Area B) referenced study to begun. demonstrate the impact, therefore monitoring of fenced and unfenced populations will be necessary. Weeds Potential Future Several weed species are present in the areas and there is concern that the weed Ruby Dock (Acetosa vesicaria) could be a competing weed source in the future.

Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) (a saltbush) Conservation Advice Page 3 of 8 Mining Expected/ Past/future Exploration drilling and Exploration potential mining was undertaken on Yeelirrie Station up to 1980 and site rehabilitation was completed in 2003.

Uranium mining is proposed with the mine impact potentially affecting all of Area B.

How judged by the Committee in relation to the EPBC Act Criteria and Regulations Criterion 1. Population size reduction (reduction in total numbers) Population reduction (measured over the longer of 10 years or 3 generations) based on any of A1 to A4 Critically Endangered Endangered Vulnerable Very severe reduction Severe reduction Substantial reduction A1 ≥ 90% ≥ 70% ≥ 50% A2, A3, A4 ≥ 80% ≥ 50% ≥ 30% A1 Population reduction observed, estimated, inferred or suspected in the past and the causes of the reduction (a) direct observation [except A3] are clearly reversible AND understood AND ceased. A2 Population reduction observed, estimated, inferred (b) an index of abundance appropriate to or suspected in the past where the causes of the the taxon reduction may not have ceased OR may not be based on understood OR may not be reversible. (c) a decline in area of occupancy, any of the extent of occurrence and/or quality of A3 Population reduction, projected or suspected to be following: habitat met in the future (up to a maximum of 100 years) [(a) cannot be used for A3] (d) actual or potential levels of A4 An observed, estimated, inferred, projected or exploitation suspected population reduction where the time period must include both the past and the future (up to a (e) the effects of introduced taxa, max. of 100 years in future), and where the causes of hybridization, pathogens, pollutants, reduction may not have ceased OR may not be competitors or parasites understood OR may not be reversible.

Evidence: Eligible under Criterion 1 A3 (c) for listing as Vulnerable. Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) is a recently discovered species which has been recorded from only two locations. A total of approximately 275,000 individuals are estimated for the two locations comprising approximately 190,700 individuals (‘Area A’) and approximately 84,500 individuals (‘Area B’). The number of female plants is unknown, therefore the number of seed bearing plants could be significantly less than the total population. The species was only recently recognised as being distinct (in 2009) and time series data on population size are not available to demonstrate whether the population size is declining, stable or increasing. Although grazing and weeds have been identified as potential threats, it is unclear whether these threats would lead to a substantial reduction in numbers. Grazing by stock is being managed through construction of fences and there are proposals for destocking. Although weeds are present in the area, and there is some concern that the presence of Ruby Dock (Acetosa vesicaria) in areas rehabilitated in 2003 after mining on Yeelirrie Station could act as a weed source in the future, there is no evidence that this (or other) weeds are currently impacting Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) populations.

Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) (a saltbush) Conservation Advice Page 4 of 8 Mining has also been identified as a potential threat, with the level of actual threat depending on the outcome of state and federal government environmental approvals processes that are currently in progress. The entire Area B population is situated above the Yeelirrie Uranium Project deposit and there is the potential for the population to be removed if this project is approved as currently proposed. The Area B population comprises one-third of the total population of the species and the overall mining impact of the current proposal is thus predicted to be 100% of the genetically distinct Area B population, or >30% of the total species abundance. The Committee considers that the species is projected to undergo a severe reduction in numbers, equivalent to at least 30 percent (and significant reduction in known genetic diversity) should the proposed mining action be approved following environmental assessment leading to a decline in area of occupancy, extent of occurrence and quality of habitat. Therefore, the species has been demonstrated to have met the relevant elements of Criterion 1 to make it eligible for listing as Vulnerable.

Criterion 2. Geographic distribution is precarious for either extent of occurrence AND/OR area of occupancy Critically Endangered Endangered Vulnerable Very restricted Restricted Limited B1. Extent of occurrence (EOO) < 100 km2 < 5,000 km2 < 20,000 km2 B2. Area of occupancy (AOO) < 10 km2 < 500 km2 < 2,000 km2 AND at least 2 of the following 3 conditions: (a) Severely fragmented OR Number of = 1 ≤ 5 ≤ 10 locations (b) Continuing decline observed, estimated, inferred or projected in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) area, extent and/or quality of habitat; (iv) number of locations or subpopulations; (v) number of mature individuals (c) Extreme fluctuations in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) number of locations or subpopulations; (number of mature individuals

Evidence: Eligible under Criterion 2 (B1, B2, (a) and (b)(i), (ii), (iv)) for listing as Endangered. The estimated extent of occurrence is less than 33 km2 and estimated area of occupancy is less than 10 km2. The extent of occurrence was calculated based on the two populations being approximately 30 km apart and the Area B population having a range of just over 4 km2. The species has been recorded at only two locations and there is a projected decline in the extent of occurrence, area of occupancy and number of subpopulations due to proposed mining. The Committee considers that the species’ extent of occurrence and area of occupancy are very restricted, and the geographic distribution is precarious for the survival of the species because its occurrence is limited and decline in extent of occurrence, area of occupancy, and number of locations may be projected. Therefore, the species has been demonstrated to have met the relevant elements of Criterion 2 to make it eligible for listing as Endangered.

Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) (a saltbush) Conservation Advice Page 5 of 8 Criterion 3. Small population size and decline

Critically Endangered Vulnerable Endangered Low Limited Very low Estimated number of mature individuals < 250 < 2,500 < 10,000 AND either (C1) or (C2) is true C1 An observed, estimated or projected Very high rate High rate Substantial rate continuing decline of at least (up to a 25% in 3 years or 1 20% in 5 years or 3 10% in 10 years or 3 max. of 100 years in future generation generations generations (whichever is longer) (whichever is (whichever is longer) longer) C2 An observed, estimated, projected or inferred continuing decline AND its geographic distribution is precarious for its survival based on at least 1 of the following 3 conditions: (i) Number of mature individuals in ≤ 50 ≤ 250 ≤ 1,000 each subpopulation (a) (ii) % of mature individuals in one 90 – 100% 95 – 100% 100% subpopulation = (b) Extreme fluctuations in the number of mature individuals

Evidence: Not eligible under Criterion 3. A total of approximately 275,000 individuals is estimated for the two locations. The number of female plants is unknown, therefore the number of seed bearing plants could be significantly less than the total population. However, it is unlikely that the total number of female plants is below the thresholds for any category under this criterion. The total number of mature individuals is approximately 275,000 so is not considered very low, low or limited. Therefore, the species has not been demonstrated to have met this required element of this criterion.

Criterion 4. Very small population

Critically Endangered Endangered Vulnerable Extremely low Very Low Low

Number of mature individuals < 50 < 250 < 1,000

Evidence: Not eligible under Criterion 4. A total of approximately 275,000 individuals are estimated for the two locations. The number of female plants is unknown, therefore the number of seed bearing plants could be significantly less than the total population. However, it is unlikely that the total number of female plants is below the thresholds for any category under this criterion The total number of mature individuals is approximately 275,000 which is not considered extremely low, very low or low. Therefore, the species has not been demonstrated to have met this required element of this criterion.

Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) (a saltbush) Conservation Advice Page 6 of 8 Criterion 5. Quantitative Analysis

Critically Endangered Endangered Vulnerable Immediate future Near future Medium-term future ≥ 50% in 10 years or 3 ≥ 20% in 20 years or Indicating the probability of extinction in generations, 5 generations, ≥ 10% in 100 years the wild to be: whichever is longer whichever is longer (100 years max.) (100 years max.)

Evidence: Insufficient data to determine eligibility under Criterion 5. Population viability analysis has not been undertaken.

Conservation Actions

Recovery Plan Recovery plan decision: No recovery plan - the approved conservation advice provides sufficient direction to implement priority actions and mitigate against key threats.

Primary Conservation Objectives 1. Maintain the number and size of wild populations by protecting habitat of extant populations. 2. Prevent the invasion or encroachment of weeds into the species’ habitat. 3. Prevent grazing by stock in the species’ habitat with ongoing monitoring of the effect of destocking on the health of fenced and unfenced populations.

Conservation and Management Actions • Manage sites to identify, control and reduce the spread of invasive species. • Manage the populations to maintain genetic diversity noting that the two populations are genetically divergent. • Identify, and where appropriate, recommend changes to development proposals that avoid impacts on the species and its habitat. • Ensure both populations A and B have adequate seed stored under ex situ conditions in at least two distinct locations (risk management) with seed stored sufficient to reinstate the populations in the event of a catastrophic decline in the species.

Monitoring and surveying priorities • Undertake survey work where potential habitat is identified to locate any additional populations/occurrences/remnants. • Monitor impacts of mining on adjacent subpopulations should mining proceed.

Information and research priorities • More precisely assess population size, distribution, ecological requirements and the relative impacts of threatening processes. • Establish additional viable populations.

Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) (a saltbush) Conservation Advice Page 7 of 8 Recommendations

(i) The Committee recommends that the list referred to in section 178 of the EPBC Act be amended by including in the list in the Endangered category: Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025)

(ii) The Committee recommends that there should not be a recovery plan for this species.

Threatened Species Scientific Committee

04/03/2015

References cited in the advice Clarke, L. J., Jardine, D. I., Byrne, M., Shepherd, K., & Lowe, A. J. (2012). Significant population genetic structure detected for a new and highly restricted species of Atriplex (Chenopodiaceae) from Western Australia, and implications for conservation management. Austalian Journal of Botany 60, 32–41.

Council of Heads of Australasian Herbaria (CHAH) (2007). Australian Plant Census. Available on the Internet at: http://www.anbg.gov.au/chah/apc/

Meissner, R. (2011). Flora and vegetation of calcrete palaeodrainage channels in the north eastern Goldfields. Draft report. Western Australia: Department of Environment and Conservation, Science Division. Available on the internet at: http://naturemap.dpaw.wa.gov.au/default.aspx (see Calcrete Survey)

Shepherd, K.A., Thiele, K.R., Sampson, J., Coates, D., & Byrne, M. (submitted). Recognition of a rare, new species of Atriplex (Chenopodiaceae) comprising two genetically distinct populations in arid Western Australia: implications for taxonomy and conservation. Submitted to the Botanical Journal of the Linnean Society.

Western Botanical. (2011). Yeelirrie Project Flora and Vegetation Survey Baseline Report February 2011, prepared for URS Australia Pty Ltd, Report Ref: WB653, for BHP Billiton Yeelirrie Development Company Pty Ltd.

Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) (a saltbush) Conservation Advice Page 8 of 8