|Scientific Name:||Arisaema heterophyllum|
Arisaema koreanum Engl.
Arisaema thunbergii Blume variety heterophyllum (Blume) Engl.
Heteroarisaema heterophyllum (Blume) Nakai
Heteroarisaema koreanum (Engl.) Nakai
Heteroarisaema manshuricum Nakai
|Taxonomic Notes:||In addition to its overall appearance, its riparian habitat relates Arisaema heterophyllum to the American A. dracontium.
Specimens close to A. heterophyllum have been found on Mt. Emei (China), near the Baguo Monastery. Gusman and Gusman (2006) consider this a geographical form of A. heterophyllum, whilst deciding whether it deserves a subspecies status.
|Red List Category & Criteria:||Least Concern ver 3.1|
Arisaema heterophyllum is a perennial herb found in central and southern China, Taiwan, Hong Kong, Japan and the Republic of Korea. It has a large estimated extent of occurrence (EOO) of more 2.5 million km2, This estimate is based on specimen data, some of which is old and some sub-populations may have been lost due to habitat conversion. However, the EOO is still inferred to exceed the threshold for a threatened category. It is often found in riparian forest and more open areas along watercourses and forest clearance, damming, pollution and conversion to rice and fish farming are all threats that are likely to directly affect this species. Its preference for riparian habitats may mean that the area of occupancy (AOO) is in decline due to the habitat changes currently occurring along many of the rivers in the region (although it was not possible to estimate actual values for present and future AOO). The species is considered threatened in Japan, where the majority of rivers have been stripped of their forest habitat (Oshima et al. 1997), and only a few patches remain. However, it is inferred that the area of occupancy (AOO) and population at present exceed the thresholds for a threatened category. In the Rare Plants Data Book of Korea it is listed as nationally Least Concern (Korea national Arboretum 2009). It is found within several protected areas and it is conserved ex situ in several botanical institutions around the world. It is assessed as Least Concern. Periodic monitoring is recommended to detect any declines as there are ongoing threats to habitat.
|Range Description:||This species extends from Japan to Central and Southern China, via Taiwan, Province of China, and Hong Kong to the west, and via the Republic of Korea to the east. Elevation range: 0-2700 m (efloras 2008).|
Native:China; Hong Kong; Japan; Korea, Republic of; Taiwan, Province of China
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There are no population data available for this species. Specimens have been collected consistently over the last 150 years, between 1863 and 2005.|
|Habitat and Ecology:||
This species is a perennial herb found in evergreen and deciduous riparian forest and deforested open sites, located in flood plains along rivers, often near sea level. In Japan it always seems to grow in areas where water deficiency hardly ever occurs and is often found among grasses. Muraoka et al. (1997) found that the most suitable habitat for this species is a forest edge or relatively well illuminated forest understory, where there is little or no water stress. It has been reported from forests, thickets and grasslands in China up to 2700 m a.s.l. (efloras 2008).
In addition to reproduction by seeds, the plants also reproduce vegetatively by cormlets formed around the maternal corm. The plant sheds its leaf in mid-summer and overwinters as corms.
|Use and Trade:||This species is an important ornamental, being much esteemed in Japan for its appearance as well as its ease of culture. It is used as a medicinal plant in China (eflors 2008). Agglutinin extracted from the species has shown promise as an effective candidate for the control of peach potato plant aphid.|
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.
|Citation:||Crook, V. 2013. Arisaema heterophyllum. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 26 October 2014.|
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