Entoloma ravinense is a small, pleurotoid, white agaric. There are several other species of similar macroscopic appearance in Entoloma, Crepidotus and Clitopilus, but E. ravinense is characterised from other genera by the angular spores. Within Entoloma, Entoloma ravinense is a species of subgenus Claudopus, section Claudopus. It differs from other white laterally attached (pleurotoid) species of Entoloma in its larger fruit bodies, close lamellae, and larger basidia, and DNA sequences do not match those of other species of the genus that have been sequenced.
There are only around 25 species in the subgenus worldwide. Noordeloos (2004) reported ten species from Europe, Horak (1980) reported five from Indomalaya and Australia and Claudopus byssisedus (Pers.:Fr.) Gillet (syn. Entoloma byssisedum (Pers.:Fr.) Donk) from New Zealand (Horak 1998). Previous to 2011, authentic Australian material existed only for Entoloma byssisedum (May & Wood 1997). Since then, three saxicolous species have been described (Claudopus rupestris Largent & Abell-Davis, C. viscosus Largent & Abell-Davis, C. minutoincanus Largent & Abell-Davis (Largent et al. 2011) and Entoloma pitereka from Tasmania, growing on the underside of rotten wood in wet eucalypt forest (Noordeloos & Gates 2012).
Entoloma ravinense was first collected in 2010, and formally described in 2016.
Entoloma ravinense is found in a specialised environment on very rotten, shed bark of Eucalyptus cladocalyx. In spite of intensive surveys in South Australia it has been found at only two sites at the western end of a small island, Kangaroo Island, off the coast of South Australia.
Entoloma ravinense has been found in a very narrow geographic range: two sites at the western end of Kangaroo Island, South Australia, Australia at a distance apart of approximately 30 km. One site is in the Ravine des Casoars Wilderness Protection Area, the other on the Rocky River Walking Trail in Flinders Chase National Park.
Populations of Eucalyptus cladocalyx occur in South Australia on Kangaroo Island, in the Flinders Ranges and Mount Remarkable National Parks and on the lower and middle Eyre Peninsula. Assuming that the one host of Entoloma ravinense is E. cladocalyx then all these areas have been surveyed by Pam and David Catcheside on a number of occasions, without finding Entoloma ravinense.
Fruit bodies of Entoloma ravinense were collected from 2010 to 2017 in the Ravine des Casoars Wilderness Protection Area, Kangaroo Island. All were in a small area of 5 m2 on the underside of shed bark of E. cladocalyx.
• 2010: a dozen fruit bodies found, scattered over bark measuring approximately 15 × 10 cm
• 2011 to 2013: no fruit bodies found
• 2014: three fruit bodies found
• 2015: seven fruit bodies
• 2016: three fruit bodies found
• 2017: eight fruit bodies found.
All collections were made at the end of June each year and in all years the surrounding area was searched thoroughly but no further fruit bodies were found.
In 2017 Entoloma ravinense was found approximately 30 km from the first at a second site which had been carefully surveyed since 2002: Rocky River Walking Trail in Flinders Chase National Park. Habitat was similar but only three fruit bodies were found.
From these data it is not possible to predict trends although we suspect that Entoloma ravinense may continue to fruit while Eucalyptus cladocalyx sheds its bark.
The pleurotoid Entolomas are often overlooked, in part due to their habitats in often cryptic places and their usually small size. Most are saprotrophic, growing on dead, often rotten wood and bark, on debris of grasses and sedges, on the ground or on mosses but occasionally parasitic on fungi such as species of Cantharellus. Species in the subgenus Claudopus are considered to be rare (Horak 1980; Noordeloos 2004)
Entoloma ravinense has been found only within a 30 km area and always on shed bark of Eucalyptus cladocalyx. Eucalyptus baxteri is another bark-shedding eucalypt which occurs in the area but, in spite of careful looking, we have not found Entoloma ravinense on its bark. Entoloma ravinense may be specific to Eucalyptus cladocalyx, possibly to the underside of shed bark and possibly from trees that have been burnt. We did not find the fungus prior to the bushfires in 2007, in spite of careful surveys.
The first area where Entoloma ravinense was found is the Ravine des Casoars Wilderness Protection Area, Kangaroo Island, South Australia, a steep sided valley vegetated by Eucalyptus cladocalyx F. Muell. and E. diversifolia Bonpl. sclerophyll forest. Fruit-bodies and an extensive mycelium were on the underside of shed, often rotting, bark of Eucalyptus cladocalyx on a north facing slope. (GPS readings: S35° 48′ 5″ to 8.7″; E136° 36′ 43″ to 50″ at an altitude of approximately 45 m.)
The second site, Rocky River Walking Trail in Flinders Chase National Park Kangaroo Island, South Australia is at a distance of approximately 30 km from the Ravine. It is Eucalyptus cladocalyx woodland with E. baxteri (Benth.) Maiden & Blakely ex J.M.Black and an understorey of Acacia paradoxa DC and Pultenaea daphnoides Wendl.. (GPS readings: S35° 57′ 4″; E136° 36′ 34″ at an altitude of approximately 10 m.)
Both areas were burnt during severe bushfires in December 2007. The vegetation is regenerating well.
Entoloma ravinense is a saprotrophic fungus, seemingly specific to the bark of Eucalyptus cladocalyx and to the underside of shed bark. The bark has often been well-rotted. The fungus was not found before the fires suggesting that it requires a burnt substrate. It is possible that the bark, shed as a result of tree death after the intense bushfires of December 2007, was in a sufficiently rotted state to provide a suitable habitat for Entoloma ravinense.
Eucalyptus cladocalyx is endemic to South Australia and is found naturally in three distinct populations, in the Flinders Ranges, Eyre Peninsula and on Kangaroo Island. It has become naturalised in Western Australia, in southern Victoria, and beyond its native range in some parts of south-eastern South Australia. It has also become naturalised in Africa, in California, Hawaii, Arizona, Israel, Chile, Greece, Portugal and Spain. Therefore there seems no threat to the ‘host’ tree of Entoloma ravinense if indeed it should prove that the fungus is specific to this host. However, because the fungus has been found so rarely, it would seem that conditions for growth may be more complex.
Lack of suitable fire regime. If it should be proven that Entoloma ravinense requires a burnt substrate then a suitable fire regime would seem necessary.
Possible clearance for track-widening to promote easier access for ecotourism.
Conservation of present habitats of Eucalyptus cladocalyx where Entoloma ravinense has been found.
Prevention of clearance of these habitats for track-widening.
Development of suitable fire regimes.
Further observations, throughout the fungal season. On Kangaroo Island this is usually from May to September. (David and Pam Catcheside have been collecting on the island since 2002 but have been unable to go to the island for more than one week each year at the end of June.) It may be possible to show Friends’ groups resident on the island what the fungus looks like and where to find it and for them to document locality, number of fruit bodies and so on.
Laboratory experiments may be possible e.g. mycelial growth on bark from different species of stringybark eucalypt; mycelial growth on unburnt to well-burnt Eucalyptus cladocalyx bark and on un-rotted to well-rotted bark.
Observations on the suitability of the substrate in relation to time since fire (is there a maximum time since fire when the substrate no longer supports the fungus).
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