Granite featherflower Verticordia staminosa subsp. cylindracea var. cylindracea 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

Verticordias, or featherflowers as they are commonly known, are among the most attractive of our native plant species. Currently, 101 species are known and these can be found scattered throughout the south-west of Western Australia. Some even occur in the arid interior.

Although many are common and widespread some are confined to very specialized habitats and several of these are currently listed as threatened. One of the rarest is Verticordia staminosa, a species that is confined to granite outcrops in the Western Australian Wheatbelt.

Verticordia staminosa has two subspecies and one of these is further divided into two varieties. All are currently declared as rare flora with two of them (Verticordia staminosa subsp. staminosa (Wongan featherflower) and Verticordia staminosa subsp. cylindracea var. erecta (pine featherflower)) ranked as Critically Endangered (CR). The third taxon, Verticordia staminosa subsp. cylindracea var. cylindracea (granite featherflower), is currently ranked Vulnerable (VU) but like the others is confined to inland granite outcrops. Interestingly, pine featherflower grows with granite featherflower at one location and the two do not appear to hybridize

Verticordia staminosa subsp. cylindracea var. cylindracea was first collected near Pingaring by Alex George and Elizabeth Berndt on 23 October 1984. The variety is currently known from nine populations and a total of approximately 1000 mature plants on granite outcrops between Pingaring and east of Newdegate.

Description

Verticordia staminosa subsp. cylindracea var. cylindracea is a small, much branched shrub with very narrow, more or less stalkless leaves to 1.5 cm long. Its solitary yellow flowers have protruding stamens 6-7 mm long that are bright red with yellow tips. Below these are yellow, very feathery sepals 5-6 mm long and two bright red persistent bracts (Brown et al. 1998; Brown 2002).

Its distinctive low, spreading habit distinguishes it from Verticordia staminosa subsp. cylindracea var. erecta that has an upright habit and can grow to 1m tall. Both varieties share floral characters that distinguish them from Verticordia staminosa subsp. staminosa; namely, smaller flowers (sepals 5-6 mm rather than 7 mm), shorter stamens (6-7 mm long compared to 9-12 mm long) that are united for half their length instead of 2-3 mm, and staminode (infertile stamens) insertion between the stamens rather than outside the staminal tube (George 1991).

Distribution and habitat

Verticordia staminosa subsp. cylindracea var. cylindracea is currently known from nine localities between Pingaring and east of Newdegate. It grows in very shallow pockets of sandy soils and humus in crevices on and fissures in bare rock on exposed granite outcrops. Associated species include Borya sphaerocephala, B. constricta, Thryptomene australis, Dodonaea viscosa, Kunzea pulchella, Stypandra glauca subsp. angustifolia, Chamaescilla sp., Melaleuca elliptica, Spartochloa scirpoidea, Acacia lasiocalyx, Allocasuarina campestris, Leptospermum roei, Platysace sp., Spartochloa sp., Baeckea crispiflora, Lepidosperma sp., Thelymitra sp., Stackhousia sp., and Diuris sp.

Populations 1, 3, 4, 5, 6 and 9 occur in CALMs Katanning District, whilst Populations 2, 7 and 8 occur in CALMs Narrogin District.

Biology and ecology

Verticordias are generally considered to be fire sensitive with post-fire regeneration occurring mainly from seed. Hybridisation between some species of Verticordia has been noted after soil disturbance or fire, however the mechanisms are unknown (George Elizabeth A. George, Honorary Curator, WA Herbarium, personal communication). Verticordias grow relatively rapidly and are often at their most floriferous stage within five years (George 2002).

The floral morphology of Verticordia staminosa differs from most species in the subgenus Chrysoma in that its staminal filaments form a tube. This, combined with the showy red and yellow colouration and the presentation of flowers hanging beneath branchlets, suggest that the species is bird pollinated (Yates and Ladd in press).

Although they did not specifically study Verticordia staminosa subsp. cylindracea var. cylindracea Yates and Ladd did study the breeding system, pollinator activity, flowering rates, frequency of pollination, seed production, seedling demography, mature plant mortality and population structure of the closely related Verticordia staminosa subsp. staminosa over a period of three years and it is likely that Verticordia staminosa subsp. cylindracea var. cylindracea would share many of the same characteristics and that the results of their research could be applied to this variety (Dr. Colin Yates, Senior Research Scientist, CALMs Science Division, personal communication).

Yates and Ladd (2004) suggest that feral honeybees (Apis mellifera) have displaced birds as the dominant visitors of Verticordia staminosa subsp. staminosa, and although the honeybee does not harvest the oily pollen, it does deplete nectar resources, changing bird foraging behavior and, potentially, patterns of pollen dispersal. V. staminosa subsp. staminosa has been found to be hermaphroditic and capable of self-fertilisation. This means that although rates of intra-plant foraging and crossing between near neighbours may have increased, there is no reduction in the number of seeds produced (Yates and Ladd 2004). Verticordia species have highly variable seed set and viability within population over different years and between populations in the same year (Anne Cochrane, Manager, CALM's Threatened Flora Seed Centre , personal communication).

The fruits of Verticordia staminosa subsp. staminosa are passively dispersed each year, and may accumulate in organic matter at the base of plants or dispersed across the rock surface by wind and water flow. Germination and growth of seedlings occurred in each year of the study but the highest numbers were associated with the wettest years. Germination and initial growth occurred in moss mats or mineral soils, but recruitment was much more likely where individuals were found in rock fissures. Yates and Ladd (2004) noted that recruitment far exceeded mature plant mortality in the three year study period.

Yates and Ladd (2004) concluded that the constraints to population growth in Verticordia staminosa subsp. staminosa were climate and suitable establishment crevices rather than the breeding system, pollinator activity or vector, or seed production. They noted that increasingly dry winters and springs in south-western Australia (CSIRO 2001, cited in Yates and Ladd, 2004) and competition from annual weeds in the rock crevices are likely to be factors affecting the long-term survival of the taxon. This seems likely to also apply to V. staminosa subsp. cylindracea var. cylindracea.

Verticordia staminosa subsp. cylindracea var. cylindracea has demonstrated a capacity for some recovery from drought stress. A number of plants observed during monitoring in June 2002 would have been considered dead, as they were mostly leafless and sometimes had also collapsed. However, following rain they produced small, vigorous tufts of new growth on the tips of old branches.

Plants have grown well in cultivation in sand and gravelly and loamy soils when given good drainage and plenty of sunshine (George 2002). They are prone to foliar fungal attack, but rarely defoliate completely and usually recover without treatment. Tip pruning and the removal of dead wood usually keeps plants growing actively (George 2002). Propagation from tip cuttings that strike readily from new growth, have sometimes proved slow and difficult to grow in the garden (George 2002)

The response of Verticordia staminosa subsp. cylindracea var. cylindracea to fire is unknown, but the species is not at risk due to the large areas of exposed granite in its surrounding habitat.

Threats

Verticordia staminosa subsp. cylindracea var. cylindracea was declared as Rare Flora on 12 March 1982 and currently meets World Conservation Union (IUCN, 1994) Red List Category VU under criteria C2a due to their being less than 10,000 mature plants, a continuing decline in the number of mature individuals and no subpopulation containing more than 1000 mature individuals. The species now meets World Conservation Union (IUCN, 2000) Red List Category VU under criteria C2a(i). The species is also listed as Endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The main threats are grazing by rabbits, drought, weeds, limited habitat, recreation, water pipeline maintenance and insecurity of tenure.

  • Rabbits and kangaroos are present at Populations 2, 5 and 7 but do not appear to graze or disturb adult plants. However, rabbits do graze native plant seedlings, presumably including those of the Verticordia thus affecting recruitment. In areas where rabbits are present there appears to be little recruitment suggesting that rabbits may be grazing on young seedlings.
  • Poor rainfall between 2000-2003has resulted in a number of plants becoming stressed. However, at least some of these plants are likely to recover following seasons of better rainfall.
  • Weeds are evident in many of the soil pockets occupied by Verticordia staminosa subsp. cylindracea var. cylindracea and may be inhibiting recruitment. Weeds also encourage grazing.
  • Limited habitat Yates and Ladd (2004) concluded that the one of the main constraints to population expansion in Verticordia staminosa subsp. staminosa was a lack of suitable soil crevices on the granite outcrop habitat of the taxon. As V. staminosa subsp. cylindracea var. cylindracea is also confined to these small soil crevices it suffers the same constraints.
  • Recreation at Pingaring rock (Population 2) may be impacting on the population. Many smaller surface rocks have been turned over and may indicate a high level of recreational use (probably due to the proximity to the golf club). Trampling and soil disturbance may have a negative effect on seedling recruitment and survival.
  • Water pipeline maintenance may impact on Population 9 as the plant is located very close to a water pipeline.
  • Insecure tenure of private property populations may result in a change of land ownership and place populations at risk from inappropriate future management practices.
  • Fire is presumed to kill mature Verticordia staminosa subsp. cylindracea var. cylindracea plants but is only a potential threat as the large surrounding areas of exposed rock prevent it from reaching most plants. However, if there were a rise in quantity of grassy weeds the threat would become more significant.

Summary of population information and threats

Pop. No. & Location Land Status Year/No. plants Condition Threats
1 Purnta Rock Water Reserve 1988 207
2000 234 (25)
2003 206 (37)
Healthy, dry conditions but plants generally healthy Some weeds
2 Eastern side of Pingaring Rock. Water Reserve 1984 30+
2003 36
Moderate, many plants appear to be dying back Some introduced weeds, rabbits, recreation
3 Marchettis Rock. Water Reserve 1985 51
200288 (7)
2003129 (16)
Healthy nil
4 Dingo Rock. Water Reserve MWA 1985 300
2002 627 (52)
Moderate Recreational activities and weeds
5a Carnaby Rock. Private Property 1988 700*
2002 75*
Undisturbed. Fenced from stock. nil
5b Carnaby Rock. Private Property 1988 700*
2002 75*
Good condition. Fenced from stock Potential threats: rabbits.
5c Carnaby Rock. Private Property 1988 700*
2002 75*
Undisturbed. Fenced from stock. Potential threats: rabbits
5d Carnaby Rock. VCL 1988 700*
2002 75*
Good condition. Fenced from stock Undisturbed. Potential threats: rabbits.
6 SW of McGlinn NR. Private Property 1996 25 (12)
2002 73 (13)
Healthy nil
7 East of Pingaring Nature Reserve 1999 100
2003 205 (1)
Healthy. Some younger plants seen Some weeds and rabbits
8 Western side of Pingaring Rock Water Reserve 2003 1 Healthy Water pipeline maintenance
9 Vernon Valley road Nature Reserve 2003 41(2) Healthy nil
Numbers in brackets = number of seedlings. * = total for both subpopulations combined.

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. (Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)).

The critical habitat for Verticordia staminosa subsp. cylindracea var. cylindracea comprises:

  • the area of occupancy of known populations;
  • areas of similar habitat within 200 metres of known populations, i.e. shallow sandy soils on granite outcrops with Borya sp. and Dodonaea viscosa (these provide potential habitat for natural range extension);
  • additional occurrences of similar habitat on nearby granite outcrops that do not currently contain the taxon but may have done so in the past (these represent possible translocation sites).

Habitat critical to the survival of the species, and important populations

Given that this taxon is listed as Vulnerable it is considered that all known habitat for wild and translocated populations is habitat critical, and that all populations, including any resulting from translocations, are important to the survival of the species.

Benefits to other species/ecological communities

Two other Declared Rare Flora (DRF) species - Verticordia staminosa subsp. cylindracea var. erecta (Pine Featherflower) and Tribonanthes purpurea (Granite Pink) occur in the habitat of Verticordia staminosa subsp. cylindracea var. cylindracea. The variety erecta is ranked as Critically Endangered (CR) and Tribonanthes purpurea is ranked as Vulnerable (VU). Both taxa are ranked as Endangered under the EPBC Act. Daviesia lineata also occurs in this general area, and is listed as Priority 2 on CALMs Priority Flora list (Atkins 2003). Recovery actions implemented to improve the quality or security of the habitat of Verticordia staminosa subsp. cylindracea var. cylindracea such as weed control and habitat rehabilitation will benefit these taxa and the remnant bushland habitat in which they occur.

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. Although the taxon is listed under the United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC) Convention on International Trade in Endangered Species (CITES) this IRP does not affect Australias obligations under international agreements.

Role and interests of indigenous people

According to the Department of Indigenous Affairs Aboriginal Heritage Sites Register, no sites have been discovered near the Verticordia staminosa subsp. cylindracea var. cylindracea populations. Input and involvement will be sought from any indigenous groups that have an active interest in the areas that are habitat for V. staminosa subsp. cylindracea var. cylindracea, and this is discussed in the recovery actions.

Social and economic impacts

The implementation of this recovery plan has the potential to have some limited social and economic impact. The variety occurs on and around large granite outcrops some of which are on private property. However recovery actions refer to continued liaison between stakeholders and negotiations have ensured that the areas that directly support the species will be left uncleared.

Guide for decision-makers

Section 1 provides details of current and possible future threats. Developments in the immediate vicinity of populations or within the defined critical habitat of Verticordia staminosa subsp. cylindracea var. cylindracea require assessment. No developments should be approved unless the proponents can demonstrate that they will not have a deleterious impact on the species, or its habitat or potential habitat, or the local surface and ground water hydrology.

Evaluation of the Plans Performance

CALM in conjunction with the Narrogin and Katanning District Threatened Flora Recovery teams (NDTFRT and KDTFRT) will evaluate the performance of this IRP. In addition to annual reporting on progress and evaluation against the criteria for success and failure, the plan will be reviewed following five years of implementation.