Dioscorea acuminata

Dioscorea acuminata is only currently known to be extant at two botanical collecting localities, one 10 km east of Ambatofinandrahana where five adult plants were located in March 2014, and one at Talatan'Angavo, in Ankazobe. The small population sizes at these two locations makes the species susceptible to stochastic events such as wildfires.

Both sites do not currently receive any formal protection and there is a risk of damage to the Ambatofinandrahana site by marble extraction by local communities which already occurs on nearby marble outcrops. Expansion of agricultural land also presents a risk to the sites; however, the terrain is largely unsuitable for farming. There is also a risk of collection by local people for consumption.The Ambatofinandrahana site is subject to pine (Pinus sp.) encroachment changing the biotope and soil pH such that they may become unsuitable for D. acuminata.

The state of the three sites where D. acuminata has not been recorded in the 21^st century (30 km south-southeast of Antananarivo; near Ambohimanga; and west of Midongy) is unknown. Assuming D. acuminata is still extant at these sites, it is likely that the threats described above also apply to these sites. These sites urgently require surveying to comprehensively assess the threat status of D. acuminata.

Currently there are no conservation measures or any designated protected sites in place for this species. No ex situ collections are listed on GeneSys or held in any seed banks. We suggest the locality 10 km east of Ambatofinandrahana where pine encroachment presents a threat to the population to be considered a site that is a priority for conservation. Survey of all historical collection sites for this species is urgently needed as it is presently only known to be extant at two sites.