The species Banksia ionthocarpa is listed Endangered under the EPBC Act and it is therefore considered that all known habitat for this species and its subspecies is habitat critical to its survival and all populations are important populations.
Benefits to other species/ecological communities: The reserves in which the species occur have high conservation value. They provide habitat for a number of other rare flora species, including Orthrosanthus muelleri (DRF), Stylidium diplectroglossum (P1), Verticordia huegelii var. tridens (P1), Chorizemacarinatum (P3), Hakea lasiocarpha (P3), Acrotriche parviflora (P3), Eucalyptus goniantha subsp. goniantha (P4), Pleurophascum occidentale (P4) and several flora species at the limits of their range.
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. Banksia ionthocarpa subsp. ionthocarpa is not specifically listed under any international treaty and therefore this plan does not affect Australia’s obligations under any other international agreements.
Role and interests of indigenous people: According to the Department of Indigenous Affairs Aboriginal Heritage Sites Register, Banksia ionthocarpa subsp. ionthocarpa Subpopulation 1A occurs at Kamballup Pool which is a registered site. Subpopulations 1A, 1B and the translocated Population 7T all occur within two kilometres of at least one of the following registered sites - Kamballup Pool, Kamballup Bridge, Kalgan Downs and Arizona Pool. The Department has welcomed all consultation seeking input and involvement from Indigenous groups that have an active interest in the areas that are habitat for B. ionthocarpa subsp. ionthocarpa. Indigenous involvement is included in the recovery actions.
Affected interests: Subpopulation 1A is on a Class C recreation reserve vested in the Shire of Plantagenet and Subpopulation 1B in an adjacent unvested Class C reserve for the purpose of public utility.
Social and economic impacts: The implementation of this plan may have some social and economic impact, as a population is located on Class C Reserves for the purposes of recreation and utility. However, the Shire of Plantagenet and the Department of Environment and Conservation (DEC) are currently considering the combination of the two reserves into one Nature Reserve. Recovery actions refer to continued negotiations between stakeholders with regard to these areas.
Evaluation of the Plan’s Performance: DEC, in conjunction with the Albany District Threatened Flora Recovery Team (ADTFRT) will evaluate the performance of this plan. 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.
Existing Recovery Actions: The following recovery actions have been or are currently being implemented in tandem to the development of this recovery plan.
All land managers have been notified of the location and threatened status of the species.
Volunteers and staff from the DEC’s Albany District regularly monitor populations.
Seed collections have been made by staff from DEC’s Threatened Flora Seed Centre (TFSC).
Seedlings are housed in the Botanic Gardens and Parks Authority (BGPA) nursery.
A Masters study has been conducted on the species’ biology and ecology.
DEC staff have investigated seedling recruitment and survival.
Soil and tissue samples have been tested for the presence of Phytophthora cinnamomi.
Access barriers have been installed to discourage entry under unfavourable soil conditions.
Fire management is implemented through the maintenance of firebreaks.
Weed management has been implemented through spraying the firebreak and the establishment of shelter bed.
A small population has been established by translocation.
A survey for new populations in similar habitat in the surrounding area has been conducted.
An information poster on the species has been developed and distributed.
The objective of this Recovery Plan is to abate identified threats and maintain or enhance in situ populations to ensure the long-term preservation of the species in the wild.
Criteria for success: The total number of mature individuals within the natural population is to remain stable or decrease by no more than 10% during the five year period of the plan.
Criteria for failure: The number of mature individuals within the natural population decreases by more than 10% during the five year period of the plan. Recovery actions
Coordinate recovery actions.
7. Conduct further surveys.
Promote awareness and encourage involvement.
Additional seed collection.
Liaise with land managers.
Map critical habitat.
Review the plan and assess the need for further recovery actions.
Obtain biological and ecological information.
History A member of the Proteaceae family, Banksia is found throughout south-west Western Australia with the highest species richness occurring around Eneabba and the Stirling Range. These areas of richness lie in the 400 to 600 mm annual rainfall zone where plants are closely associated with extensive areas of Kwongan or sclerophyllous shrublands (Kershaw et al. 1997). Banksia species are sclerophyllous, perennial shrubs, restricted to well-drained sandy or lateritic soils (Monks 1999).
Banksia ionthocarpa subsp. ionthocarpa was discovered near Kamballup by P. Luscombe who made the first collection of it in 1987. Considerable survey effort throughout the surrounding district has failed to find another population despite extensive searches of what appears to be suitable habitat.
Due to the low number of plants and the threats associated with existence as a single population in a highly specific habitat, Banksia ionthocarpa subsp. ionthocarpa was declared as Rare Flora in Western Australia in July 1989 (as Dryandra ionthocarpa) and ranked as Critically Endangered in September 1995 (Kershaw et al. 1997). In 1999 a new population of this species was located near Narrogin. In 2004, the species was divided into two subspecies - B. ionthocarpa subsp. ionthocarpa (Kamballup) and B. ionthocarpa subsp. chrysophoenix (Narrogin). Plants in the Narrogin population resprout from a lignotuber, in contrast to the Kamballup plants that are non-lignotuberous and are therefore killed by fire (Barrett and Cochrane 2004).
In 1999 and 2000, 283 seedlings were translocated to Kalgan Plains Nature Reserve, near Kamballup in an area of similar habitat to the natural population. Six of these individuals flowered for the first time in the 2003 flowering season. However, survival was poor and, by 2004, the population consisted of just 46 individuals. In 2005, an additional 566 plants were translocated into this area.
Banksia ionthocarpa subsp. ionthocarpa is a caespitose, tufted shrub with a very short stem and leaves up to 30 cm long. The leaf lobes are broadly triangular, up to 8 mm and cut within 1.5 mm of the midrib. It is a non-sprouter with pale yellow flowers borne close to the ground within the leaves. The subspecies has characteristic follicles, that are not woody, differing from those found in most Banksia species. Each follicle contains one seed, is about 5 mm in size and covered in 7 to 8 mm long erect hairs. The subspecies is also unusual in having floral bracts that do not elongate as the fruit develop. The robust pistils are prominently bowed before anthesis, then recurved very strongly afterwards. The species’ epithet is taken from the Greek ionthas (shaggy) and carpos (a fruit), in reference to the prominent tuft of hairs on the follicle (George 1996).
Distribution and habitat
Banksia ionthocarpa subsp. ionthocarpa is known from a single natural population comprising two subpopulations, in the Kamballup area. Its extent of occurrence is less than one kilometre and total area of occupancy is less than five hectares. The population supports 945 mature plants in total. Subpopulation 1A is on a Class C recreation reserve vested in the Shire of Plantagenet and Subpopulation 1B in an adjacent unvested Class C reserve for the purpose of public utility. The unvested reserve has in the past been subject to mining for spongolite stone and the mine is in close proximity to the plants. However, mining is not currently being undertaken and there are no current mining tenements approved or pending approval on this land (1D. Coffey, personal communication).
The subspecies occurs on clay-loam over spongolite, underlaid by the Late Eocene Plantagenet group geological formation (spongolite with minor siltstone and sandstone), in open shrub mallee habitat with Eucalyptus falcata, E. pleurocarpa and scrub of Melaleuca spp., Allocasuarina thuyoides, Beaufortia micrantha, Isopogon buxifolius, Verticordia sp. and Xanthorrhoea platyphylla. Vegetation surrounding Banksia ionthocarpa subsp. ionthocarpa is predominantly less than one metre high and consists entirely of small shrubs and herbaceous species (Monks 1999).
Banksia ionthocarpa subsp. ionthocarpa has been translocated to Kalgan Plains Nature Reserve, near Kamballup. The translocation is considered to be an ‘introduction’ as the subspecies is not known to have occurred naturally at this site in the past, however it is within the known range of the subspecies and in similar habitat. The site has similar climatic conditions, geology and vegetation.
Biology and ecology The seeds of Banksia ionthocarpa subsp. ionthocarpa are quite different to those of most other Banksia species in that they lack a wing; instead the follicles have a small tuft of hairs that appear to be designed to stick to fur (Kershaw et al. 1997). It is suggested that the subspecies is mammal pollinated due to the dull appearance, low positioning and strong smell of the inflorescences, as well as the large number of viable seeds produced (Monks 1999).
A study conducted by Leonie Monks, then of Curtin University, found that Banksia ionthocarpa subsp. ionthocarpa did not regenerate from rootstock following fire, however seedlings did recruit after fire. A large amount of viable seed is produced annually, which is mostly dispersed as the seed crop ripens. Seed that does not disperse may remain viable within the cones, naturally deteriorate or be predated. Favourable post-fire conditions, in particular following adequate rainfall, may be imperative as the majority of seedlings die from drought over summer (Monks 1999; Barrett and Cochrane 2004). A very small number of seedlings underneath live plants were observed in the absence of fire, however none survived over summer (Barrett and Cochrane 2004). The species was concluded to have the attributes of a nonsprouter with seedling recruitment confined to the post fire period.
Banksia ionthocarpa subsp. ionthocarpa is thought to be weakly serotinous with little significant seed bank stored in the canopy or soil (Monks 1999). Consequently, poorly timed fires, i.e. in spring or summer, could have a very detrimental effect on the population (Monks 1999). However, in a study by Barrett and Cochrane (2004), 76% of D. ionthocarpa subsp. ionthocarpa seed was found to remain intact in the soil for at least nine months. The ability for viable seed to persist in the soil was confirmed by seedling germination observed in spring 2004. Forty-nine seedlings germinated in the second spring post-fire, however survival has been poor to date, with only 10% surviving to mid-December after a dry spring. No seedlings germinated around control or smoke treated plants in 2004 (S. Barrett, unpublished data).
There are no reliable data on the longevity of Banksia ionthocarpa subsp. ionthocarpa and the juvenile period for naturally occurring plants is unknown (Monks 1999). However, six translocated plants in 1999 were recorded to have flowered for the first time in 2003 (Monks (1999) determined that there is a linear relationship between plant height, volume, diameter and number of cones. It is estimated that individuals begin to set fertile cones once a height of approximately 0.3 metres is reached (Monks 1999). Barrett and Cochrane (2004) found that D. ionthocarpa subsp. ionthocarpa cone load varied considerably between plants and was related to crown volume, while the magnitude of post-fire recruitment was related to the canopy seed bank.
Seed viability studies indicated the potential longevity of the species’ seed under a range of storage conditions (Barrett and Cochrane 2004). Greatest viability was obtained from fresh seed, with 78% germination achieved without treatment. Soil-stored seed ranged from 50% to 65% germination. Under laboratory conditions, 64% of seed stored for one year at –20OC and 62% of seed stored at ambient temperature for ten years germinated with no treatment (Barrett and Cochrane 2004).
In the same study, fire was undoubtedly the most significant stimulus for seedling emergence. Smoke treatment resulted in minimal germination of the soil-stored seed (five germinants). In laboratory studies germination of seed treated with smoke water was less successful than germination of seed with no treatment (63% compared to 78%). The few recruits observed around unburnt plants failed to survive through summer, supporting observations that inter-fire recruitment is unlikely to significantly augment population numbers (Barrett and Cochrane 2004).
Monks (1999) found the number of seedlings recruited per parent plant after the first summer was considerably lower than would be expected for a non-sprouter in southwestern Australia (1.4 seedlings per parent plant in Population 1A and 0.2 seedlings per parent plant in Population 1B). Barrett and Cochrane (2004) concluded that initial recruitment may vary considerably within and between subpopulations and from year to year. This variation may be due to the canopy-stored seed bank of individual plants as well as seed predation pre- and post-dispersal. Post-dispersal predation may be intensified when small experimental plots are burnt and predator satiation does not occur. It is possible that recruitment under a more extensive burn may have been higher (Barrett and Cochrane 2004). However, poor seedling survival after the first summer was the critical factor limiting successful recruitment.
Threats Banksia ionthocarpa subsp. ionthocarpa was declared as Rare Flora in July 1989 under the Western Australian Wildlife Conservation Act 1950). The subspecies is currently ranked as Critically Endangered against World Conservation Union Red List Criteria B1ab(v) and B2ab(v) (IUCN 2001) due to a decline in the number of mature individuals, a single known population and the limited area of occupancy and extent of occurrence. The species, Banskia ionthocarpa is listed as Endangered under the Commonwealth Environment and Biodiversity ProtectionAct 1999 and both subspecies are covered by this listing.
One natural population consisting of two subpopulations totalling 945 plants over less than five hectares is currently known. A translocated population supports another 612 individuals.
All habitat occupied by this taxon are currently affected by threats identified in this Recovery Plan. Threats include the following.
Inappropriate fire regime: Both natural subpopulations occur in long-unburnt habitat, estimated at around twenty-five years of age. While occasional fire is required for seedling recruitment, inappropriate timing, intensity and frequency of fire may be detrimental, as plants need to reach reproductive maturity to build up a seed bank. For species with a soil-stored seed bank, a conservative estimate for the minimum desirable fire interval may be determined by multiplying the primary juvenile period (time to first flower) by two and a half (Gill and Nichols 1989). The juvenile period for Banksia ionthocarpa subsp. ionthocarpa is unknown but is thought to be a least four years to first flowering.
Banksia ionthocarpa subsp. ionthocarpa seedling survival post-fire is poor and unpredictable. If conditions are not favourable for seedling recruitment and survival in the year mature plants are burnt, population decline is likely to be substantial.
It is considered that the rubbish dump to the south of the population is a potential fire hazard. In the past, neighbouring landholders have requested that the two reserves be burnt as they were considered a fire hazard to surrounding farmland. Subsequently, the Shire of Plantagenet constructed firebreaks around the reserve boundaries. A firebreak is also maintained between the two subpopulations as it is important to ensure that the two do not burn at the same time.
Drought: Drought is a threat to both subpopulations because of the skeletal soils and rocky substrate on which the subspecies grows. Drought may directly impact the subspecies by reducing flowering, seed set and population recruitment, and by increasing plant mortality (Barrett and Cochrane 2004).
Decline in the number and health of Banksia ionthocarpa subsp. ionthocarpa was observed from 1991. A survey of Population 1 in 1994 suggested that the species was suffering from drought. Phytophthora cinnamomi was ruled out as a possible cause through laboratory tests and field observations.
In 1995 and 1996, a study by Leonie Monks used the monitoring of the plants’ water potential (xylem tension) and changes in photosynthetic pigments to determine the level of water stress within the population. All plants were found to be under some level of water stress in the 1995/96 summer drought, although orange and intermediate coloured plants were under more stress than green coloured plants. The presence of orange foliage was considered a good indicator of water stress. Orange and intermediate coloured plants are thought to be more likely to recover over winter than die, however these plants became orange and intermediate again at the onset of the next period of summer drought. This indicated that either the plants had not fully recovered to pre-stress levels and would therefore succumb to the next summer drought, or plants with naturally lower chlorophyll levels are more prone to drought stress (Monks 1999).
Monks (1999) also monitored the recruitment and survival of seedlings post-fire. A significant loss of seedlings occurred following summer drought, with only 3.3% of the Subpopulation 1A seedlings and 8.3% of Subpopulation 2A seedlings surviving the first summer period (Monks 1999). Experimental watering of seedlings that appeared in 2003 was trialled (Barrett and Cochrane 2004), 52% of watered seedlings survived through to spring 2004 compared to the 5% survival of the seedlings that were not watered (S. Barrett, unpublished data). Hence, drought poses a considerable threat to the survival of recruited seedlings.
Weed invasion: Weeds that suppress early plant growth by competing for soil moisture, nutrients and light are often blown in from adjoining pasture (Panetta and Hopkins 1991). Weed invasion is a particular threat to subpopulation 1A as it is relatively exposed and therefore subject to influences from adjacent cleared farmland. Influences include the introduction of exotic species, farm chemicals, modified hydrology and altered disturbance regimes (Panetta and Hopkins 1991).
Despite spraying the firebreak with Roundup® and planting a shelterbelt of Eucalyptus spp., weeds have persisted in subpopulation 1A, primarily at the edge. Weeds include paddy melon (Cucumis myriocarpus), capeweed (Arctotheca calendula) and veldt grass (Ehrharta longiflora) (S. Barrett, personal observation.). Rust was introduced to the bridal creeper (Asparagusasparagoides) in 2002 as the weed has the potential to spread rapidly through the area. The rust appears to be having some affect (S. Barrett, personal communication).
Weeds were more abundant in experimental plots after fire and were removed by hand (S. Barrett, personal communication). Post-fire conditions can be advantageous for weed invasion and reciprocally, the presence of weeds can encourage fire through altering the nature and spatial array of the fuel load (Panetta and Hopkins 1991).
Disease: Phytophthora cinnamomi is an introduced soil-borne plant pathogen. Infection results in plant death in susceptible species through the destruction of root systems. The impact of the disease on plant communities is variable as it is dependent on temperature, soil type, nutrient status, water and species susceptibility. The greatest impact usually occurs where soils are infertile and drainage is poor. Banksia ionthocarpa subsp. ionthocarpa occurs in a winter-wet, poorly drained site, which is likely to favour P. cinnamomi infestation.
In general, Banksia species are highly susceptible to Phytophthora spp. and research has shown that Banksia ionthocarpa subsp. ionthocarpa is susceptible.. However, Phytophthora cinnamomi has not been identified with any deaths of D. ionthocarpa subsp. ionthocarpa and the population currently appears to be P. cinnamomi-free. Soils and tissues samples were collected from Population 1 in 1994. Both samples tested negative for P. cinnamomi. A sample was again taken in 2001, which also produced a negative result, indicating thatP. cinnamomi had not infected the population at that time, however due to the access tracks passing through the habitat, the threat of pathogen spread is high (2P. Collins, personal observation).
Aerial canker has in the past been observed on Banksia ionthocarpa subsp. ionthocarpa (Kershaw et al. 1997), However no further research has been done on the presence of this fungus. The effect of aerial canker on the population requires further investigation.
Altered hydrology: It has been predicted that altered hydrology will cause the loss of habitat in many reserves if present trends continue. One quarter of southwest landscapes and up to half of some landscapes in low catchment areas may become salt-affected over the next century (Monks 1999). While the reserve in which Banksia ionthocarpa subsp. ionthocarpa occurs is low in the catchment and adjacent to the salt-affected Kalgan River, the population occurs at a relatively high altitude in the landscape and may be less vulnerable to the impacts of altered hydrology (S. Barrett, personal communication).
The presence of adjacent farmland can lead to increased run-on, often vectoring surplus chemicals and nutrients (Panetta and Hopkins 1991). This may have a detrimental effect not only on Banksia ionthocarpa subsp. ionthocarpa, but also on the remainder of the reserve plant community.
Herbivory: Seed predation will reduce the number of viable seeds available for dispersal. In one year, insects destroyed 46% and 60% of follicles respectively in the two Banksia ionthocarpa subsp. ionthocarpa subpopulations. The insect attack seemed to occur very early in the inflorescence development. While some follicles remain intact even after invasion, studies have shown that the application of insecticide just after pollination increases the number of intact cones. (Monks 1999).
There have been no obvious grazing effects on mature plants, however seedlings are subject to grazing by invertebrates and possibly vertebrates. Of the seedlings recruited in 2003, 37% showed effects of grazing and a further 11% died, most likely as a result of grazing. Grazing affects seedling vigour and survival. Only 65% of 2003 seedlings that were grazed survived to Dec 2004 (Barrett and Cochrane, unpublished data).
Land tenure:Population 1 occurs in two Class C reserves, one for the purpose of public utility (spongolite mine) and the other for recreation (golf course). The Shire of Plantagenet and DEC are currently considering the combination of the two reserves into one Nature Reserve. Whilst there are no mining tenements currently approved or pending approval on this land (D. Coffey, personal communication), likely effects of mining or recreational use if approved in the future would include soil compaction, clearing and damage to vegetation, significant amounts of water and nutrients added to the soil and an increase in the likelihood of disease spread as a result of vehicle movement.
Climate change: Long-term climate change is likely to adversely affect the single known Banksia ionthocarpa subsp. ionthocarpa population given a predicted decrease in rainfall and an increase in temperature and evaporation. Current seedling survival is poor, primarily as a result of drought stress and any further adverse change in conditions due to climate change will be severely detrimental to recruitment. It is thought that groups likely to be most affected by climate change include geographically localised taxa such as B.ionthocarpa subsp. ionthocarpa, peripheral or disjunct populations, specialised species, poor seed dispersers, genetically impoverished species, and coastal communities.