As all Mesophellia sp. are ectomycorrhizal, the main threat to their populations is clearing (cutting down) of host plants. I (SN) have used this threat to estimate the geographically and ecologically distinct area that is relevant for a populations of M. brevispora as land clearing can be a single threatening event that can rapidly and significantly negatively impact the individuals present.
In south-western WA, 90% of the primary vegetation (original total 310,000 km2) had been cleared (Bradshaw 2012). Most of the clearing happened before the late 1980’s and in that decade between 300-600 km2 had been approved by the government for clearing. Based on this estimate, the total uncleared area is ~31,000 km2 (10% of 310,000 km2). Large areas were cleared from 1890’s onwards and most of this clearing happened in 1945-1982 (Bradshaw 2012), which is within 3 generations (50 years) estimated for ECM species (Dahlberg and Mueller 2011).
If the rate of clearing per decade was 300-600 km2, then over 50 years (3 generations) this area could potentially be 1500-3000 km2. However, within some areas the rate of clearing was higher; within the Biodiversity Hotspot of the south-western Western Australia (‘wheatbelt’), from the 1890’s until 1968 (7.8 decades or 4.68 generations), 130,000 km2 was cleared which could mean >83,000 km2 over 3 generations ((130,000/4.68)*3), or >55,000 km2 in 2 generations. If the total vegetated area before clearing was 310,000 km2 and the potential area lost as habitat for M. brevispora over 3 generations could range from 0.5-26.9% (between (1500/310,000)*100 = 0.48 and (83,333/310,000)*100 = 26.9) or over 2 generations range from 0.3-17.9%. That’s assuming that the total area was/is suitable habitat for M. brevispora and the area cleared represents a population decline.
To estimate the number of individuals, we need to have an estimate for the number of functional individuals (and unrecorded functional individuals) per location and the number of locations and unrecorded locations per subpopulation. I estimate that 10 functional individuals can be found per location with a possible 30 not found (total 40). M. brevispora has been found at 4 locations thus far. The total area left uncleared is ~31,000 km2 (10% of 310,000 km2). I used the rate of clearing per generation as an estimate of the area significant for M. brevispora populations (500 km2). I.e. if 50 years is 3 generations then 16.7 years is one generation. The lowest rate of clearing per decade stated by Bradshaw (2012) was 300 km2 per decade, or 501 km2/ECM generation (300*1.67). Based on this, the estimated number of uncleared for M. brevispora is up to 62 locations (31,000/500). M. brevispora has been recorded from 4 locations. Therefore, the number of potential unrecorded locations in 58 (62-4). The estimate of the total number of mature individuals is 40*62 = 2480.
At the higher rate of clearing, this places this species under Vulnerable (A1 and C1).
This species was described by Trappe et al. 1996. Below is a quote from their description:
“Mesophellia brevispora is the western analogue of the eastern M. clelandii. The latter species lacks the open pockets and veins in the glebal core that abound in M. brevispora.”
There are only 6 independent collections of this species from 4-5 locations that are within 500 km from each other. Based on existing records, the current estimated Extend of Occurrence is ~12,000 km2. Current threats include land clearing, loss of ectomycorhizal hosts and loss of mammalian dispersers. These threats have been well documented in this species range.
This species was erected in 1996 from two specimens collected in 1928 and 1975. It has since been recorded 4 times in locations < 500 km from the first two locations, with the most recent record in 2007.
South-west of Western Australia. There are 5 distinct locations from a single subpopulation (
<500 km); Bald Island Nature Reserve, Perup Nature Reserve, Walpole National Park, Boyicup and Applecross.
The population that the collection from Applecross represents (suburb near Perth, collected in 1928 by H. Perry) is likely to be extinct because this area is now heavily urbanised. It is highly likely that the host ectomycorrhizal trees have been cleared since 1928 and its main spore dispersers, mycophagous mammals, are locally extinct. Applecross only has a few degraded remnant vegetation patches on the nearby Wireless Hill. Mycologist, Neale Bougher, has sampled macrofungi (including truffles) in similar urban locations around Perth (Kings Park and Bold Park) for well over a decade and has not found any Mesophellia spp. in these locations. Therefore, it is likely this population no longer exists. If this is the case, 4 distinct locations are currently known. Attached is a map of these locations and the EOO and AOO calculated by
Mesophellia spores were found in mycophagous Potorous gilbertii scats at Two Peoples Bay Reserve, near Albany WA (Nguyen et al. 2005) however, the species was not identified. This is within 30 km from Bald Island where M. brevispora was collected in 2005 and 2007 and could represent another location within this subpopulation. Other rare, short range endemic hypogenous fungi have also been found at Two People Bay where a remnant population of the endangered truffle eating specialist (Potorous gilbertii) resides (May 2002).
I infer that this species’ populations are declining because at least one locality has potentially been lost since 1928 (Applecross) and its habitat is declining from land clearing (see Red List Justification) and threatened by Phytophthora dieback. Additionally, two mammal species which are probably the main dispersers of this species (and other truffle-like fungi in the region) have declined severely and are Critically Endangered (see Threats).
Other collections for M. brevispora were made in 1975 at Boyicup, in 1993 at Walpole NP, in 2000 at Perup Nature Reserve and in 2005 and 2007 at Bald Island. As this is a hypogeous species, it is most probably under surveyed compared to epigeous fungi. However, the south-western corner of WA is more densely surveyed for fungi than other parts of WA (May 2002), mainly due to research by mycologists Neale Bougher, Mark Brundrett and Richard Robinson and truffle surveys in the endangered mycophagous mammal habitat.
Population Trend: Decreasing
All members of Mesophelliaceae are thought to be ectomycorrhizal and incorporate ectomycorrhizae in their peridium. All Mesophellia sp. require animals for dispersal, mainly mammals. The mammals break open the crusty outer layers to reach a sterile edible core. In doing so the powdery spores are dispersed via either ingestion by the animal, carried on the outside of the animal or dispersed via wind or soil movement.
Recorded in Eucalyptus conferruminata and Taxandria sp. mallee woodland (Neale Bougher, https://mycorrhizas.info/ecmf.html#).
As this is an ectomycorrhizal species the main threat would be land clearing. This would be most prominent in areas affected by urban expansion (around Perth) and clearing for agriculture. Over 90% of native vegetation has been cleared since European settlement in the south-west of Western Australia where this species is found (Bradshaw 2012).
Jarrah forest, which is the habitat for this species, is heavily impacted by forest dieback caused by Phytophthora sp. This pathogen causes mortality in trees and can adversely affect the abundance and diversity of ectomycorrhizal fungi in affected forests (Anderson et al. 2010).
All Mesophellia sp. require animals to dig up and expose their spores for dispersal via the animals’ scats, wind or soil movement. Therefore, local extinction of mycophagous mammals can also pose as a threat to this species. Critically Endangered species’ the Gilbert’s Potoroo, Potorous gilbertii, and Woylie, Bettongia penicillata ogilbyi, have declined dramatically in the region where M. brevispora is found (Bougher and Friend 2009, Zosky et al. 2017). These species were most probably the main dispersers for truffle-like fungi in this region (Nuske et al. 2017) and now exist in remnant, fragmented populations. This Bettong species used to be very wide spread across Australia and now exists in ~1% of its former range (Department of Parks and Wildlife, Western Australia), including locations where M. brevispora is found. The Gilbert’s Potoroo used to be wide spread throughout the south-west of WA but now only exists in isolated populations at Two Peoples Bay and nearby islands where M. brevispora is found (Bald Island).
Other mycophagous mammals that exist in this area and could contribute to dispersal of M. brevispora are
- wallabies (Macropus eugenii, Least Concern; Macropus irma, Near Threatened in WA, Least Concern nationally),
- bandicoots (Isoodon obesulus, Least Concern nationally, I. o. fusciventer subspecies is endemic to south-west WA, listed as Least Concern but recent surveys show it is declining (WWF-Australia and Department of Parks and Wildlife 2012)),
- rodents (Rattus fuscipes, Least Concern; Pseudomys albocinereus, Least Concern; Rattus rattus, Introduced; Mus musculus, Introduced),
- possums (Pseudocheirus occidentalis, Critically Endangered; Pseudocheirus peregrinus, Least Concern nationally but less common in south-west WA), Trichosurus vulpecula, Least Concern nationally but subspecies endemic to south-west WA, T. v. vulpecula is Endangered and T. v. hypoleucus has declined and is Near Threatened),
- quokka (Setonix brachyurus; Vulnerable).
Further research is needed to determine whether these other mycophagous species can maintain the dispersal of populations of M. brevispora and other endemic truffles in south-west WA in the absence of specialist mycophagists (bettongs and potoroos).
Other threats could include inappropriate fire regimens, changes in precipitation and extremes in temperature associated with climate change and pollution and/or nutrient deposition and excessive fertilisation.
There are currently no conservation actions for this species.
- Sequencing of specimens to confirm species distinctiveness
- Targeted searches for this species around collection locations and elsewhere in similar habitat.
- Dispersal ecology of M. brevispora. Particularly the dispersal by a variety of mycophagous mammals (rats, bandicoots, wallabies, etc) and the role of Critically Endangered specialist mycophagous mammals (bettongs and potoroos)
- habitat characterisation and ecotomycorrhizal host range
- Identification of Mesophellia sp. collections in herbaria (note: there are 111 records of on the Australian Living Atlas recorded as Mesophellia sp.)
Advice to the Minister for the Environment, Heritage and the Arts from the Threatened Species Scientific Committee on Amendment to the list of Threatened Subspecies under the Environment Protection and Biodiversity Conservation Act 1999. 2008. . https://www.dpaw.wa.gov.au/images/documents/plants…/woylie_fauna_profile.pdf
Anderson, P., M. Brundrett, P. Grierson, and R. Robinson. 2010. Impact of severe forest dieback caused by Phytophthora cinnamomi on macrofungal diversity in the northern jarrah forest of Western Australia. Forest Ecology and Management 259:1033–1040.
Bradshaw, C. J. A. 2012. Little left to lose: Deforestation and forest degradation in Australia since European colonization. Journal of Plant Ecology 5:109–120.
Bougher, N. L., and J. A. Friend. 2009. Fungi consumed by translocated Gilbert’s potoroos (Potorous gilbertii) at two sites with contrasting vegetation, south coastal Western Australia. Australian Mammalogy 31:97–105.
Dahlberg, A., and G. M. Mueller. 2011. Applying IUCN red-listing criteria for assessing and reporting on the conservation status of fungal species. Fungal Ecology 4:147–162.
May, T. W. 2002. Where are the short-range endemics among Western Australian macrofungi? Australian Systematic Botany 15:501–511.
Nguyen, V. P., A. D. Needham, and J. A. Friend. 2005. A quantitative dietary study of the “Critically Endangered” Gilbert’s potoroo Potorous gilbertii. Australian Mammalogy 27:1–6.
Nuske, S. J., K. Vernes, T. W. May, A. W. Claridge, B. C. Congdon, A. Krockenberger, and S. E. Abell. 2017. Redundancy among mammalian fungal dispersers and the importance of declining specialists. Fungal Ecology 27:1–13.
Trappe, J. M., M. A. Castellano, and N. Malajczuk. 1996. Australasian Truffle-like Fungi. VII. Mesophellia (Basidiomycotina, Mesophelliaceae). Australian Systematic Botany 9:773–802.
WWF-Australia, ., and W. A. Department of Parks and Wildlife. 2012. Community Quenda Survey 2012 Report.
Zosky, K. L., A. F. Wayne, K. A. Bryant, M. C. Calver, and F. R. Scarff. 2017. Diet of the critically endangered woylie (Bettongia penicillata ogilbyi) in south-Western Australia. Australian Journal of Zoology 65:302–312.