Attention: Taxonomic position in GFRLI should be changed - in species fungorum and literature, the species is classified as Boletaceae, Boletales, not Hydnangiaceae
Note: For the map, I added centroid point in Borneo Malaysia. There is no specific information for the site where the species was found, and selecting the whole area in Borneo could give a wrong idea of its distribution.
Durianella echinulata is a gasteroid fungi found in Peninsular and Borneo Malaysia. It has only been documented from 3 sites in 1932, 2005 and 2006. Because of the inconspicuousness of this fungi it is likely that the species is more common than reported and the population size is estimated to be up to 30000 individuals. Though this species’ population size is difficult to estimate due to the absence of more current records, the levels of deforestation in the area suggest that it is likely in decline. Population size reduction due to habitat loss is expected to be above 30% for a 50 year period and therefore D. echinulata qualifies as Vulnerable A2c+4c.
Only member of the monotypic genus Durianella, created in 2008 using morphological and molecular data (Desjardin et al., 2008). The species was originally named Hydnangium echinulatum (Corner and Hawker, 1953).
Attention: Family on GFRLI differs from Species Fungorum. No longer part of Hydnangiaceae - now Boletaceae.
This species is known from Peninsular Malaysia (specifically Sungai Nipah in Kemaman, Trengganu, and the Hutan Lipur Sungai Congkak Forest Reserve in Selangor) and from one unspecified site in Malaysian Borneo. (Corner and Hawker, 1953 and Desjardin et al., 2008)
This species has only been documented in 3 sites in Malaysia, once in 1932, and then in 2005 and 2006. The authors of Desjardin et al. (2008) are not aware of any re-attempts at finding it since. For this reason, it is difficult to estimate whether this is a rare species, or if it is under documented.
Considering these 3 sites, and the inconspicuousness of this fungi, the population size is estimated at 30000 individuals (3 sites x 100 mature individuals x 1000 multiplier), using the guidelines in Dahlberg and Mueller (2011). However, this assumes that all sites have remained intact, with mature, fruiting individuals, including the one found in 1932 (Sungai Nipah).
Nevertheless, given the deforestation in Malaysia the population of Durianella echinulata is expected to be in decline. Data from Estoque et al. (2019) can be used to estimate a 33% decrease in forest cover in Malaysia from 2000 to 2050. This corresponds to a 50 year period needed to estimate population declines for mychorrhizal fungi (Dahlberg and Mueller, 2011). For the Borneo island specifically, a decrease in 33% of forest area between 1973 and 2015 is estimated using data from Gaveau et al. (2016). Consequently, population size of D. echinulata is expected to have decreased above 30% due to habitat loss.
Population Trend: Decreasing
D. echinulata is an epigeous gasteroid fungi that grows on soil, solitary or in small clusters. It was found in secondary forest and is thought to be ectomycorrhizal with Shorea spp. (Dipterocarpaceae). (Desjardin et al, 2008)
Southeast Asia is a major global deforestation hotspot. Both Peninsular Malaysia and Borneo Island have suffered significant deforestation and conversion of forest areas to oil palm and pulpwood industry plantations in the last decades. (Gaveau et al., 2016) This decline in areas of suitable habitat is likely causing a decline in population size for Durianella echinulata.
One of the locations where D. echinulata was found is part of the forest Hutan Lipur Sungai Congkak Forest Reserve. Nevertheless, this location should be monitored, along with the Trengganu site. It is also essential to protect dipterocarp forests that may constitute a habitat for this species in order to halt its population decline.
Known sites for D. echinulata need to be monitored to confirm the presence of fruiting individuals. Search efforts in areas of appropriate habitat and research into its ecology and habitat preferences are also needed to obtain better estimates of distribution and population size of D. echinulata.