Spiral flag Patersonia spirafolia interim recovery plan 2004-2009

Western Australian Threatened Species and Communities Unit (WATSCU) © The Western Australian, Department of Conservation and Land Management, 2004

1. Background

History

The first collection of Patersonia spirafolia was made in 1984 from the Badgingarra area by G.J. Keighery, and the taxonomic description was published in 1990. P. spirafolia was declared to be Rare Flora in November 1997 under the Wildlife Conservation Act 1950 after additional surveys confirmed the rarity of this species. Two additional populations on road reserves have been located since then. Population 4 was discovered in April 2001, and Population 5 in April 2003. All five populations occur within the Badgingarra area. Of the five populations, four contain fewer than twenty plants, and all but one are on road reserves.

Population 3, that contained six plants in 1996, was graded during road maintenance in 1997, before the species was declared as Rare Flora and before the shire was aware of this population. Regeneration monitoring recorded six plants there in 2003, suggesting all individuals successfully resprouted.

Populations 1 and 5 were burnt in a wildfire in December 2002. Since then, Population 5 has regenerated well in its relatively sandy habitat. Only one unburnt plant has since been seen at Population 1 since the fire, and there is concern that the plants rhizomes may have been killed during the fire by the heat from the massive laterite underneath this population. Monitoring will occur after the rains in winter 2004, and it is hoped that more plants may have regenerated after this second post-fire winter season.

Description

Patersonia spirafolia is a perennial herb to 50 cm tall, with a spreading woody rootstock producing a tussock to 40 cm across. The leaves are linear, up to 20 cm long and 5 mm wide, and spirally twisted. The brown leaf margins have fringes of soft hairs that point towards the centre of the leaf. The scape is up to 25 cm long, 1-2 mm wide and reddish-green. The spathe (a leaf-like structure enveloping the inflorescence) is brown, lanceolate in shape and up to 26 mm long with thin, almost transparent margins. The flowers have three broad spreading blue-violet sepals to 19 mm long and 14 mm wide, and three upright blue-violet petals about 1 mm long. The seed capsule is roughly egg-shaped and up to 3 cm long (Keighery 1990; Patrick and Brown 2001).

Patersonia spirafolia is grouped with other Western Australian species of Patersonia which form tussocks, namely P. inaequalis and P. drummondii. It differs from P. inaequalis in having purple flowers and brown spathes, and from P. drummondii in the short appressed hairs on the leaf margins and in the shorter spathes, which are brown when flowering occurs (Keighery 1990).

Distribution and habitat

Patersonia spirafolia is currently known over a range of less than 10 km south west of Badgingarra. A total of 465 plants are known from 5 populations. The largest of these (437 plants) is on a road reserve near a National Park. The population in National Park was burnt over a year ago and is yet to regenerate, while the others are on road reserves and are still in reasonably good condition. The species is found on lateritic ridges and slopes, or sand over laterite in low species-rich heath. Associated species include Allocasuarina humilis, Gastrolobium spinosum, Daviesia chapmanii, D. epiphyllum, Xanthorrhoea preissii, Mesomelaena stygia, M. tetragona and Patersonia occidentalis.

Biology and ecology

Patersonia spirafolia produces a rootstock that is a spreading woody rhizome, forming a tussock to 40 cm across. This has enabled the plant to regrow after being graded at Population 3, and after fire at Population 5. No germination of seed was noted after either event.

High levels of seed abortion and seed predation by insects have been observed. The causes of seed abortion are unknown. A germination trial conducted at CALMs Threatened Flora Seed Centre (TFSC) obtained 20% germination using a growth hormone (gibberellic acid), and noted that it took one month before any germination was observed, and another month for germination to be complete.

Threats

Patersonia spirafolia was declared as Rare Flora in November 1997 under the Wildlife Conservation Act 1950. P. spirafolia is also listed as Endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). It currently meets Red List (IUCN 2000) Category Endangered (EN) under criteria B1ab(iii,v)+2ab(iii,v) and C2a(ii)b as there are only five populations, with over 95% of plants in one population, the number of adult plants fluctuates widely, and there is continuing decline in the quality of habitat. Two new populations have been located and the total number of known mature plants has increased recently, but the species is still threatened because the plants are largely concentrated in one population on a road reserve, and there is likely to be a continuing decline in the quality of habitat as a consequence of dieback present at this largest population. The main threats are road, powerline and firebreak maintenance, disease, inappropriate fire regimes and poor recruitment.

  • Road, powerline or firebreak maintenance threaten all populations. Threats include grading, chemical spraying, construction of drainage channels and the mowing of roadside vegetation. Several of these actions also encourage weed invasion.
  • Disease could be a serious threat to Population 5. The presence of Phytophthora cinnamomi has been confirmed in the area. This plant pathogen (dieback) causes the roots to rot and can result in death from drought stress. The susceptibility of Patersonia spirafolia to this pathogen is unknown. The species may not be susceptible as it is thought to have the ability to grow new roots annually, which could replace those affected. However many of the components of the species-rich heath habitat that occurs at this site are characteristically susceptible to the disease and changes in the structure of the habitat caused by dieback may then impact on the P. spirafolia population. This may include impacts such as opening up the canopy, and altering levels of shade and humidity.
  • Inappropriate fire regimes may affect the viability of populations. P. spirafolia resprouts from a rhizome following fire or physical removal of above-ground parts. Although regeneration appears to be vigorous at Population 5, there is concern that the rhizome of plants at Population 1 may not have survived the intense fire that occurred in December 2002. The location of the rhizomes in rock crevices would have exposed them to high temperatures in addition to the burning of above-ground parts. The effect of fire on germination is unknown, but no germination was noted following the 2002 fire. Frequent fire is also likely to degrade the supporting ecological community, altering species composition as well as fostering weed invasion and erosion.
  • Poor recruitment is apparent at all populations with no juvenile plants recently observed. This may be due to low levels of viable seed production or may be related to an absence of germination triggers.

Summary of population information and threats

Pop. No. & Location Land Status Year/No. plants Condition Threats
1. SW of Badgingarra National Park 1996 200+
2003 1
Burnt 12.02 Firebreak maintenance, inappropriate fire regimes
2. SW of Badgingarra Main Roads WA (MRWA) road reserve 1996 2
2003 4
Healthy Road maintenance, inappropriate fire regimes
3. SW of Badgingarra Shire road reserve 1996 6
1997 0
2000 3
2001 7
2003 6
Moderate Road maintenance, inappropriate fire regimes
4. SW of Badgingarra MRWA road reserve 2003 17 Moderate Road and powerline maintenance, inappropriate fire regimes
5. SW of Badgingarra Shire road reserve 2003 20
2004 437
Healthy Road maintenance, dieback, inappropriate fire regimes

Guide for decision-makers

Section 1 provides details of current and possible future threats. Any on-ground works (clearing, firebreaks, roadworks etc) in the immediate vicinity of Patersonia spirafolia will require assessment. On-ground works should not be approved unless the proponents can demonstrate that they will not have an impact on the species, or on its habitat or potential habitat.

Critical habitat

Critical habitat is habitat identified as being critical to the survival of a listed threatened species or listed threatened ecological community. Habitat is defined as the biophysical medium or media occupied (continuously, periodically or occasionally) by an organism or group of organisms or once occupied (continuously, periodically or occasionally) by an organism, or group of organisms, and into which organisms of that kind have the potential to be reintroduced (EPBC Act).

Patersonia spirafolia is listed as Endangered, and it is therefore considered that all known habitat for wild and translocated populations is critical habitat. This includes:

  • the area of occupancy of populations;
  • areas of similar habitat within 200 metres of populations, i.e. sand over laterite in low species-rich heath (these provide potential habitat for natural range extension);
  • corridors of remnant vegetation that link populations (these are necessary to allow pollinators to move between populations and are usually road and rail verges); and
  • additional occurrences of similar habitat that do not currently contain the species but may have done so in the past (these represent possible translocation sites).

Benefits to other species or ecological communities

Daviesia chapmanii (Priority 4) and D. epiphyllum (Priority 3) are both associated with Patersonia spirafolia, and are listed on CALMs Priority Flora list (Atkins 2003). Recovery actions such as maintaining dieback hygiene at Patersonia spirafolia populations will also help to conserve the ecological community in which the populations are located.

International Obligations

This plan is fully consistent with the aims and recommendations of the Convention on Biological Diversity, ratified by Australia in June 1993, and will assist in implementing Australias responsibilities under that Convention. However, as Patersonia spirafolia is not specifically listed under any international agreement, the implementation of other international environmental responsibilities is not affected by this plan.

Role and interests of indigenous people

Indigenous communities interested or involved in the regions affected by this plan have not yet been identified. The Aboriginal Sites Register maintained by the Department of Indigenous Affairs does not list any significant sites in the vicinity of these populations. However, not all significant sites are listed on the Register. Input and involvement will be sought from any indigenous groups that have an active interest in the areas that are habitat for Patersonia spirafolia, and this is discussed in the recovery actions.

Social and economic impacts

The implementation of this plan is unlikely to cause significant adverse social or economic impact as populations exist in National Park and on road reserves. However, recovery actions will involve liaison and cooperation with all stakeholders.

Evaluation of the Plans Performance

CALM will evaluate the performance of this IRP in conjunction with the Moora District Threatened Flora and Communities Recovery Team. In addition to annual reporting on progress with listed actions and comparison against the criteria for success and failure, the plan is to be reviewed within five years of its implementation.