Arisaema heterophyllum

Due to forest clearing, the wet conditions required by this species are becoming rare, and in Japan it is considered a threatened species, where it has been listed in the national plant Red-Data Book (Muraoka et al. 1997). Conversion of forest to farmland is occurring throughout the region and this species is likely to have lost a significant extent of suitable habitat over the last few years, particularly in China. An example of this is given by changes within ecoregions where the species is found: for example the Jian Nan subtropical evergreen forests ecoregion, where mos native vegetation has been extirpated. Lowlands have been converted to rice paddy agriculture for centuries and some areas have been more recently converted to plantations of the native conifers Pinus massoniana and Cunninghamia lanceolata. Riverine habitats are also under significant threat, with pollution, damming and conversion of flooded areas to rice and fish farming being prevalent threats (Carpenter 2001). In the Changjiang Plain evergreen ecoregion, hundreds of miles of river have been contained between earthen banks and there are severe hydrological and ecological consequences to the Three Gorges Dam Project (Carpenter 2001).

There has been a recent increase in interest for cultivating Arisaema species (D. Roberts pers. comm. 2008) and it is used as a medicinal plant in China (efloras 2008), and harvesting from the wild may be a threat for this species.

This species is found in several "country parks" in Hong Kong and it is cultivated, with plants growing in several botanical institutions around the world, such as the Botanical Garden in Komaba, Japan; Juniper Level Botanic Garden, Raleigh, US (plants originally from Kaichen Nursery, China); and The Royal Botanic Gardens, Kew, UK (three plants derived from seed from South Korea). The seeds stored in the Millennium Seed Bank, UK, were collected from South Korea. It is also recorded from protected areas such as the Taeanhaean National Park in Korea, the Taroko National Park in Taiwan and the Baishui Jiang Nature reserve in China, although many herbarium records from China fall outside protected areas.

Oshima et al. (1997) concluded that active management of riparian forest in Japan is required to prevent invasion of bamboo into the forests, as this would prevent regeneration of species such as this, species which need the moderate light environment normally found in these forests understories.