Trapa natans 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Myrtales Trapaceae

Scientific Name: Trapa natans L.
Regional Assessments:
Common Name(s):
English Water Caltrop, Water Chestnut
French Châtaigne d'Eau, Mâcre, Mâcre nageante
Trapa astrachanica (Flerow) N.A.Winter
Trapa carinthiaca (Beck) V.N.Vassil.
Trapa colchica Albov
Trapa conocarpa (F.Aresch.) Flerow
Trapa cruciata (Glück) V.N.Vassil.
Trapa europaea Flerow
Trapa hungarica Opiz
Trapa maeotica Woronow
Trapa muzzanensis (Jäggi) Szafer
Trapa rossica V.N.Vassil.
Trapa septentrionalis V.N.Vassil.
Trapa spryginii V.N.Vassil.
Taxonomic Notes: The taxonomy of the genus Trapa appears to be complex. The distribution of T. natans sensu stricto is obscured by variation in the degree to which other taxa are recognised. It is likely that the information employed here will include information on other taxa and will therefore present a more positive idea of the status of the species than is actually the case.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2017
Date Assessed: 2016-06-14
Assessor(s): Gupta, A.K. & Beentje, H.J.
Reviewer(s): Luke, W.R.Q.
Contributor(s): Allen, D.J.
Facilitator/Compiler(s): Maiz-Tome, L.
The species is widespread and although it is declining in Europe it is widespread across Asia and Africa and is not thought to be in risk of extinction on a global level.
Previously published Red List assessments:

Geographic Range [top]

Range Description:The species has a wide distribution through Europe, Africa and Asia. It has been reported as present in most of Europe, southern Sweden and into European Russia. It occurs throughout most of Asia, China, the Philippines and Malaysia. It has apparently been introduced into Australia and North America where it is now widespread and may be invasive (Arber 1920, Cuong et al. 1973, Crow and Hellquist 2000, Tzvelev 2005, Chen et al. 2005, USDA 2010).
Countries occurrence:
Afghanistan; Albania; Algeria; Angola; Austria; Bangladesh; Belarus; Botswana; Bulgaria; Cameroon; Central African Republic; Chad; China (Anhui, Fujian, Gansu, Guizhou, Hainan, Hebei, Heilongjiang, Henan, Hubei, Jiangsu, Jilin, Liaoning, Nei Mongol, Qinghai, Shaanxi, Shandong, Xinjiang, Yunnan, Zhejiang); Congo, The Democratic Republic of the; Croatia; Czech Republic; France (France (mainland)); Gabon; Germany; Ghana; Greece (Greece (mainland)); Guinea-Bissau; Hong Kong; Hungary; India; Indonesia; Italy (Italy (mainland)); Japan; Kazakhstan; Kenya; Kyrgyzstan; Lao People's Democratic Republic; Latvia; Liechtenstein; Malawi; Malaysia; Moldova; Mongolia; Montenegro; Mozambique; Myanmar (Myanmar (mainland)); Namibia (Caprivi Strip); Nepal; Nigeria; Pakistan; Philippines; Poland; Romania; Russian Federation (Central European Russia, East European Russia, European Russia, North European Russia, Northwest European Russia, South European Russia); Serbia (Kosovo, Serbia); Slovakia; Slovenia; South Africa; South Sudan; Spain (Baleares, Spain (mainland) - Regionally Extinct); Sudan; Sweden; Switzerland; Taiwan, Province of China; Tajikistan; Tanzania, United Republic of; Thailand; Tunisia; Turkey (Turkey-in-Europe); Uganda; Ukraine (Krym, Ukraine (main part)); Uzbekistan; Viet Nam; Zambia; Zimbabwe
Regionally extinct:
Australia; United States
Additional data:
Upper elevation limit (metres):1150
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:There is little information about population sizes or trends.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This plant is an annual floating-leaved plant that grows in stagnant waters, lakes, channels with weak currents, ponds and swamps. It primarily occurs in unpolluted nutrient-rich lowlands without too much calcium; it is important as a food source for birds and provides fish spawning habitat.
Continuing decline in area, extent and/or quality of habitat:No

Use and Trade [top]

Use and Trade: The fruits are important in continental Asia, Malaysia, India and especially in China. Several countries in southeast Asia and also Chinese communities in Europe and North America import the fruit directly from China. It is widely cultivated across the region. Fruits are used in the preparation of liniments to treat elephantiasis, pestilent fevers, rheumatism, sores, sunburn and skin complaints. Used also as food for pigs and other livestock in southeast Asia.

In India, the kernel of the plant is used as a laxative and is a good source of nutritious flour. The unripe kernels are also used as a vegetable or eaten raw. The flour of the dried kernel provides a good source of income for people across India and Nepal.

Threats [top]

Major Threat(s): In Europe the species is declining, however, the causes of the decline are not clear although they are usually attributed to loss and degradation of habitats. In Asia and Africa there seem to be no significant threats to the species although wetland loss and degradation are likely to become significant there too.

Conservation Actions [top]

Conservation Actions: The species is included in some regional and national red lists in Europe but no global conservation actions are required.

Citation: Gupta, A.K. & Beentje, H.J. 2017. Trapa natans. The IUCN Red List of Threatened Species 2017: e.T164153A84299204. . Downloaded on 19 September 2018.
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