Assessment Notes

Justification

Bondarzewia retipora is an Australian endemic only known from six collections from four sites representing three subpopulations separated by 400-1600 km. It is a large and distinctive bracket fungus fruiting on large, dead, standing tree trunks in wet sclerophyl forests. The population is undergoing continuing decline due to increased frequency of severe storms knocking down the required standing dead trees, an increase in frequency and intensity of bush fires, and continued disturbance by feral animals in parts of its range. Accounting for the likely number of unrecorded sites the estimated population size is 400-1600 mature individuals. It is likely that there are more than 250 mature individuals in the largest subpopulation, but fewer than 1000. The species is therefore assessed as Vulnerable C2a(i), D1.

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Geographic range

This is a large and distinctive Australian endemic bracket fungus which fruits on large, dead, standing tree trunks in wet sclerophyl forests. It is only currently known from six collections from four sites: three from Queensland and one from New South Wales. It has also been recorded in Victoria and Western Australia, but no collections have been made in these regions since 1933 and 1972 respectively so it is unknown if these two subpopulations are extant, and precautionarily assumed that they are not. The three known extant subpopulations (two in Queensland, as two of the Queensland sites are in close proximity, and one in New South Wales) are distant from each other with the closest pair of sites being separated by over 400 km and the most distant by 1600 km.

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Population and Trends

The species has rarely been reported despite the fact that it is large and distinctive. While there are only four confirmed sites, due to the relative abundance of the habitat it is estimated that there are up to 400 unrecorded sites each with 1-2 sporocarps, giving an estimated number total of 400-1600 mature individuals. These individuals are distributed among three subpopulations (two in Queensland and one in New South Wales) separated by between 400 and 1600 km. The populations are continuing to decline, due to the increasing frequency of significant storms knocking over standing dead trees plus increased frequency and intensity of bush fire.

Population Trend: decreasing

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Habitat and Ecology

Bondarzewia retipora is a wood inhabiting fungus that fruits on large, dead, standing tree trunks in wet sclerophyl forests. Due to the few known records, information on its ecology and habitat requirements are inadequate to explain its apparent rarity across its broad geographic range.

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Threats

The locations at which this fungus occurs are well protected in National Parks or Wildlife Reserves. The subtropical rainforest habitat in which the fungus is found has undergone substantial reduction since European settlement in the mid nineteenth century. In 2003 Coger et al. estimated that only 1/3 of these forest remained on the ranges of South East Queensland. Neldner et al. (2017) demonstrated that the rate of loss has continued in the next decade and losses are still occurring. The remaining forests have become fragmented by land clearing for agriculture and substantial development pressure for house building and the creation of lifestyle properties in South-eastern Queensland and Northern New South Wales has seen further forest losses.

Feral animals have a large effect on many Australian habitats with cattle, horses, camels, deer, pigs, dogs, cats, rabbits and toads amongst the many introduced animals that inhabit our forests. For fungi it is thought that wild pigs and cattle may have the most significant effects. Pigs impact fungi populations by digging large areas of soil and by consumption of fruit bodies, and cattle by trampling and increasing nitrogen levels. 

Climate change is also beginning to have an effect with increasing temperatures, more intense droughts and more intense rain events all causing discernible damage. Recent experience in Queensland has also suggested that subtropical rainforest is not immune to fire events.

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Conservation Actions

This fungus is considered to be of least concern in Queensland under current legislation, as this is the state's default position on fungi species. However, recognition of the species in the management plans for the three National Parks in which it has been found would secure additional safeguards.

Research is needed on the host association and biology of this fungus as this is not well understood.

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Use and Trade

This species is not utilised.

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Source and Citation

Leonard, P.L. 2019. Bondarzewia retipora. The IUCN Red List of Threatened Species 2019: e.T154430456A154430616. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T154430456A154430616.en .Accessed on 7 February 2024

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• Country occurrence