Gingin Wax (Chamelaucium sp. Gingin) Interim Recovery Plan 2003-2008

Gillian Stack and Val English
Department of Conservation and Land Management, WA, 2003

1. Background

History

Chamelaucium sp. Gingin was known to local farmers and nurseries for many years prior to the official recognition of the species as distinctly different. It was first recognised as a new species when G. Lullfitz, an established nurseryman, brought the species to the attention of N. Marchant ¹. Between 1991 and 1994 various Departmental staff then extensively surveyed the area of the Darling Scarp near the original location. In 1995 D. Papenfus ² located an additional three populations after an intensive survey of the area. A fifth population was located on private property in 1997. To date there are only five known populations of this species. These are confined to a very limited geographical range and are highly fragmented.

An Interim Recovery Plan was developed for Chamelaucium sp. Gingin in 1999 (Evans and English 1999). This plan is based on that document, includes additional information compiled since 1999, and replaces that plan.

Description

Chamelaucium sp. Gingin is an open straggly shrub 1 to 2 m tall with many slender stiff branches that bear numerous 5 to 20 mm long axillary shoots. Its erect, glandular, bright green leaves are 5.4-11.5 mm long by 1.2-1.4 mm wide, and are scattered along the main branches, but are mostly crowded on numerous short axillary shoots. Leaves are attached to a 0.5-1.5 mm long petiole, which is frequently appressed to the stem. The inflorescence is composed of a small head on short axillary shoots or sometimes a larger flower head at the end of main branches. The 6.6 - 9.2 mm flowers occur in groups of two to nine in small heads on axillary shoots. Up to 20 flowers are held in clusters at the end of main branches. The flowers are pale pinkish-white, and the buds are tinged a deeper pink. The calyx lobes are erect, ovate, glandular, 2-2.8 mm long and have margins that are irregularly denticulate and ciliate. The erect corolla lobes are 4.6-6 mm long, and are covered with fine scattered glands. The corolla margins are irregularly denticulate and very sparsely but finely ciliate.

Distribution and habitat

Chamelaucium sp. Gingin is endemic to Western Australia and is apparently confined to the Gingin area. It is known from a range of only 3 km. The six known populations contain a total of approximately 4700 adult plants and 1800 juveniles. The species occurs on white/yellow sand supporting open low woodland over open scrub, with Eucalyptus todtiana, Banksia attenuata and Hibbertia sp. Chamelaucium sp. Gingin does not occur in the nearby Adenanthos cygnorum and Kunzea ericifolia thickets.

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 Chamelaucium sp. Gingin comprises:

  • the area of occupancy of known populations;
  • areas of similar habitat within 200 metres of known populations, i.e. white/yellow sand supporting open low woodland over open scrub (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).

Although a description of location and habitat requirements is provided, adequate spatial data/maps have not been included as these are not yet available. Recovery actions include reference to mapping of critical habitat.

Threats that apply to individual populations are listed in table 1, below.

¹ Dr. Neville Marchant, Group Manager, the Department's Western Australian Herbarium
² Diana Papenfus, previously consultant to the Department's Western Australian Threatened Species and Communities Unit

Habitat critical to the survival of the species, and important populations
Given that this species is endangered it is considered that all known habitat is habitat critical. In addition all populations are considered important to the survival of the species as genetic variation between populations and/or individual plants has not been determined. Recovery actions include survey for further populations that would lead to the identification of additional habitat critical.

Benefits to other species/ecological communities
Population 1a is also located within an occurrence of a Threatened Ecological Community (TEC) (English and Blyth 1997) listed as Endangered in Western Australia. Gibson et al. (1994) describe the community as 'Banksia attenuata woodland over species-rich dense shrublands'. Recovery actions implemented to improve the quality or security of the habitat of Chamelaucium sp. Gingin Population 1a are likely to improve the status of the TEC in which this population is located.

Biology and ecology

Chamelaucium sp. Gingin appears to be a reasonably long lived taxon, with plants in Population 1a known to be up to 16 years old prior to a fire in January 1995. Some adult plants survived due to protection provided by the landholder. The landholder also noted that the species tends to produce suckers after fire. The plants then take up to five years before flowers and seeds are produced. Due to the species' ability to sucker, it is possible that the genetic diversity within populations is low and this has implications for reproductive capacity.

European bees, native bees, native wasps, flies, and beetles have all been observed feeding on the nectar. A. Cochrane 3 has noted European bees and ‘small furry’ native bees pollinating the taxon, but has also noted a low seed set, with many seeds aborting or not being pollinated.

To date there has been no field observation of the natural seed dispersal mechanisms, however, germination of seedlings in new areas has been achieved through movement of sand from underneath mature plants (landholder personal communication) The landholder also noted that germination was enhanced following the fire in 1995, and that reducing the competition from species with dense habit, such as Adenanthos cygnorum and Kunzea ericifolia, helps the plants to thrive.

Most plants in one Population on private land were burnt and killed in an intense fire in January 1995. Some 30 plants survived where the fire was contained by the local bush fire brigade. As the plants take five years to reach maturity and produce seed, a fire frequency of five years or less would severely threaten this species.

Anecdotal evidence suggests that Chamelaucium sp. Gingin is frost resistant as mature plants on a landholder's property were observed to survive a very heavy frost in 1987, and winter frosts are common in the area (landholder, personal communication.).

Chamelaucium sp. Gingin appears to be a disturbance opportunist. It occurs only on disturbed road reserves, firebreaks, powerline maintenance tracks, and in burnt bushland. A landholder cleared around juveniles of this species occurring near thicket areas and recorded ‘superior survival’ of the taxon as a consequence of reduced competition (landholder, personal communication). In a number of areas firebreaks have been installed or maintained and a proliferation of juveniles has been observed. It seems likely that many of these are rootstocks regenerating after the disturbance. This has also been observed following fire (Harris, unpublished report).

A number of taxa in the genus Chamelaucium are susceptible to dieback caused by Phytophthora spp., however resistance to the disease varies between species (personal communication G. Keighery 4). Initial tests indicate that Chamelaucium sp. Gingin is highly susceptible to Phytophthora cinnamomi (personal communication B. Shearer 5)

There is little information about predation of flowers and fruit, or response to weed invasion and herbicide application.

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 Australia's responsibilities under that Convention. However, as Chamelaucium sp. Gingin is not listed under any international agreement, the implementation of other international environmental responsibilities is not affected by this plan.

Role and interests of indigenous people
There are no known indigenous communities involved in the management of areas affected by this plan. Therefore no role has been identified for indigenous communities in the recovery of this species.

Social and economic impacts
There are mineral leases over the area that contains population 1a of Chamelaucium sp. Gingin (refer Table 1), however, negotiations are in train with relevant State Agencies and lease holders with regard the future management of these areas. There are also populations located on private land. Recovery actions refer to continued negotiations between stakeholders with regard these areas.

Evaluation of the Plan's Performance
The Department of Conservation and Land Management, in conjunction with the Recovery Team will evaluate the performance of this IRP. 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.

3 Anne Cochrane, Manager, the Department's Threatened Flora Seed Centre
4 Greg Keighery, Principal Research Scientist, the Department's Science Division
5 Dr Bryan Shearer, Principal Research Scientist, the Department's Science Division

Threats

Chamelaucium sp. Gingin was declared as Rare Flora under the Western Australian Wildlife Conservation Act 1950 in September 1986 and ranked as Critically Endangered (CR) in November 1998. It is also listed as Endangered under the EPBC Act. It is now to be recommended for listing under World Conservation Union (IUCN, 2000) Red List category 'VU' because it meets criterion B1ab(iii)+2ab(iii) for Vulnerable (due to the severe fragmentation of populations and continuing decline in the quality of habitat) and no longer meets criteria for Endangered. The level of threat to the species has declined recently as a consequence of the acquisition of two properties that contain populations of the species for conservation, and other recovery actions.

The main remaining threats are road, track, firebreak and fence maintenance activities, road construction projects, mining, inappropriate fire regimes, grazing, weed invasion, chemical drift and potentially disease.

  • Road, track, firebreak and fence maintenance activities threaten all road reserve populations and most populations on private property. Threats include grading, chemical spraying, construction of drainage channels and the mowing of roadside vegetation. Several of these actions also encourage weed invasion.
  • Road construction may threaten Populations 1a and 1e. The proposed Perth-Darwin Highway Corridor goes through the area of Population 1e, and the Shire of Chittering advised the Department in February 2000 that a link road to the Highway may transect the north east corner of the proposed Nature Reserve that contains Population 1a.
  • Mining is a threat to Population 1a as a mining lease exists over the site, and the leaseholder was investigating the viability of this area for mining in September 2000. The pursuit of this goal is affecting the process of the site becoming an A Class Nature Reserve.
  • Inappropriate fire regimes may affect the viability of populations, as seeds of Chamelaucium sp. Gingin germinate following fire. The soil seed bank may rapidly be depleted if fires recurred before regenerating or juvenile plants reached maturity and replenished the soil seed bank. However, it is likely that occasional fires are needed for reproduction of this species. Field evidence suggests that it takes five years for plants to reach maturity and to flower and produce seed. It is thought that regeneration also occurs from root stock after fire, and this material may be able to flower and produce seed within a shorter period.
  • Grazing by rabbits (Oryctolagus cuniculus) has had a minor impact on all populations. In addition, disturbance of soil from rabbit warren construction, and the increased levels of nutrients and weeds from droppings is affecting the habitat of the species. Grazing may also limit natural recruitment through impacting the establishment of juvenile plants of Chamelaucium sp. Gingin.
  • Trampling by stock may be occurring in Population 1a, as cattle appear to come in from the south east corner of the Reserve, but do not seem to graze this species.
  • Weed invasion is a threat to isolated sections of some road reserve populations, although generally invasion is low. Weeds suppress early plant growth by competing for soil moisture, nutrients and light. They also exacerbate grazing pressure and increase the fire hazard due to the easy ignition of high fuel loads, which are produced annually by many grass weed species.
  • Chemical drift of herbicide and fertiliser applications may affect populations of Chamelaucium sp. Gingin close to farmland.
  • Disease is a potential threat, as dieback (caused by Phytophthora spp.) is thought to be spreading through the broader area. Chamelaucium sp. Gingin appears to be highly susceptible to this plant pathogen and the prevention of the spread of dieback into the habitat of the populations is therefore very important. Dieback can also have an indirect impact through degradation of habitat.
Table 1: Summary of population information and threats
Pop. No. & Location Land Status Departmental District Year/No. plants Condition Threats
1a. South of Gingin Proposed Nature Reserve Perth Hills 1995 78
2000 724 (269)
Healthy Firebreak maintenance activities, mining, road construction, cattle degrading habitat, inappropriate fire regimes
1b. South of Gingin Private property Swan Coastal 1995 1
2000 2
Healthy Firebreak maintenance activities, inappropriate fire regimes
1c. South of Gingin Road reserve Perth Hills and Swan Coastal 1996 290
2000 482 (185)
Healthy Road and fence maintenance activities, weed invasion, inappropriate fire regimes
1d. South of Gingin Private property Swan Coastal 1996 170
2000 482 (177)
Healthy Firebreak maintenance activities, inappropriate fire regimes
1e. South of Gingin Private property Perth Hills 1999 226 (367)
2000 241 (78)
Healthy Road, firebreak and powerline maintenance activities, road construction, inappropriate fire regimes
2a. South of Gingin Private property Swan Coastal 1996 2
1999 6 (4)
2000 8 (6)
Healthy Firebreak and fence maintenance activities, road realignment, inappropriate fire regimes, disease
2b. South of Gingin Road reserve Swan Coastal 2000 2 Healthy Road and fence maintenance activities, weed invasion, inappropriate fire regimes
3a. South of Gingin Road reserve Perth Hills and Swan Coastal 1995 300
2000 386 (186)
Healthy Road and firebreak maintenance activities, inappropriate fire regimes, disease
3b. South of Gingin Private property Swan Coastal 2000 128 (37) Healthy Firebreak maintenance activities, inappropriate fire regimes
4a. South of Gingin Private property Swan Coastal 2000 200+ (140+) Healthy Firebreak maintenance activities, inappropriate fire regimes
4b. South of Gingin Proposed Nature Reserve Swan Coastal 1995 200+2000 ca. 850 (ca 500) Healthy Firebreak and fence maintenance activities, inappropriate fire regimes
4c. South of Gingin Private property Swan Coastal Unknown (seen, but not surveyed)   Firebreak and fence maintenance activities, inappropriate fire regimes
5. South of Gingin Private property Swan Coastal 1997 ca. 5002000 ca. 600 Healthy Weed invasion, inappropriate fire regimes
6a. South of Gingin Private property Swan Coastal 2000 314 (136) Healthy Firebreak and fence maintenance activities, inappropriate fire regimes
6b. South of Gingin Private property
(Western Power powerline strip)
Swan Coastal 2000 367 (108) Healthy Firebreak and powerline maintenance activities, inappropriate fire regimes

Numbers in brackets = number of juveniles.

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 Chamelaucium sp. Gingin 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, its habitat or potential habitat.