Download Crinum thaianum, Onion Plant

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IUCN 2008: T201627A9154955
Crinum thaianum, Onion Plant
Assessment by: Soonthornnawaphat, S., Bambaradeniya, C. & Sukpong, P.
View on www.iucnredlist.org
Citation: Soonthornnawaphat, S., Bambaradeniya, C. & Sukpong, P. 2011. Crinum thaianum. The
IUCN Red List of Threatened Species 2011: e.T201627A9154955.
http://dx.doi.org/10.2305/IUCN.UK.2011-2.RLTS.T201627A9154955.en
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THE IUCN RED LIST OF THREATENED SPECIES™
Taxonomy
Kingdom
Phylum
Class
Order
Family
Plantae
Tracheophyta
Liliopsida
Liliales
Amaryllidaceae
Taxon Name: Crinum thaianum J.Schulze
Common Name(s):
• English:
Onion Plant, Thai Water Onion, Water Onion
Assessment Information
Red List Category & Criteria:
Endangered B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v) ver 3.1
Year Published:
2011
Date Assessed:
June 6, 2008
Justification:
The Water Onion has a very restricted range in southern Thailand, with an extent of occurrence of about
641 km² and an area of occupancy of about 48 km². The population is severely fragmented by habitat
loss (only 3-5% of the original habitat remains) and there has been rapid population declines in some
areas as a result (70% decline in the Nakha River during the period 2003-2008), and there has been local
extinction in some streams within its range. The threats to the habitats and the species (exploitation)
are all ongoing, hence there is continuing decline in a number of parameters. The species is therefore
listed as Endangered and it could well become Critically Endangered in the near future if these trends
continue.
IUCN staff in the region are trying to raise awareness about this species and have also been promoting
habitat restoration and reintroduction projects in an effort to conserve this species.
Geographic Range
Range Description:
Originally found on the coastal plain of southern Thailand (Leeratiwong and Jornead 2005), but is now
confined to isolated patches on a few rivers and streams in Phang Nga and Ranong provinces. Phang Nga
province: Khlong Khura Buri/ Nang Yon, Khlong Banglu, Khlong Tam Nung, Khlong Ban Krung, Khlong
Bang Pao Moo and Ranong province: Khlong Nakha; Khlong Kapoe, Khlong Bangpong, Khlong Suan Mai,
Khlong Ta Pud (http://www.dnp.go.th; IUCN survey). Occurs at low elevations below 150 m.
Country Occurrence:
Native: Thailand
© The IUCN Red List of Threatened Species: Crinum thaianum – published in 2011.
http://dx.doi.org/10.2305/IUCN.UK.2011-2.RLTS.T201627A9154955.en
1
Population
The population is very fragmented and declining.
Current Population Trend: Decreasing
Habitat and Ecology (see Appendix for additional information)
This geophytic plant grows in clear running fresh water, usually in wide and open streams and rivers a
few centimetres to two meters in depth depending on the seasonal water level. The soil is usually a
sandy loam or mixed gravel. Some streams are shaded, however, in all their sites Crinum receive sunlight
at least temporarily (http://www.amaryllidaceae.org). It prefers water temperatures of 22-30°C.
Mature bulbs reach 7 cm in diameter and about 15 cm high. The elongated (up to two metres long) float
in the direction of the current, or in stiller water are piled in loops. Flowering occurs mainly during the
monsoon season (August-October). The inflorescence comprises five to eight flowers. The plant also
reproduces vegetatively through the production of bulblets. The data on the phenology of water onion
and water depth in Nakha river, maintained by Mrs. Oy Onkhow (co-leader of a local community based
organization – ‘Pleun Prai Sri Naka’ - involved in conservation work in Ranong Province, highlights the
following: January (average water depth of 3-4 m): germination from seeds and leaf production from
bulbs starts
February - July (average water depth starts at 1-2 m in March and increases to 5-6 m by July): leaf
growth
August (average water depth 6-8 m): flowering is initiated
September (average water depth 8-9 m): peak flowering
October (average water depth 6-9 m): seed formation
November to December (average water depth drops from 6 m down to 4 m): seed is dispersed and laves
die back
Preliminary observations on the mid areas of the Nakha River, by a team of IUCN scientists on the 3rd of
June 2008 revealed the following: The speed of water flow in mid areas of Nakha River ranged from
0.25-3 m/s. The main population is restricted to a 600 m stretch (width – 30 m; depth 1-2.5 m), which
has a muddy substrate. The growth was very dense towards the edge of the river. The water flow in this
stretch was below 0.3 m/s. The area received ample sunlight. The length of the leaves ranged from 1-3
m, with each bulb having 20-40 leaves. Several fish were observed in this stretch, beneath the thick
growth of this plant, which provided an ideal refuge to them. A thin layer of sediment was clearly visible
on the leaf surface. Clumps of washed out Water Onion were observed on either side of the river bank,
these had been removed by the fast flow of the water.
The Water Onion is a very important aquatic plant that functions as a keystone species in its aquatic
habitats. It provides important habitat for native freshwater fish species such as the Soro Brook Carp
(Tor soro), which use it as a habitat to lay eggs. Other aquatic species such as water snails and frogs also
© The IUCN Red List of Threatened Species: Crinum thaianum – published in 2011.
http://dx.doi.org/10.2305/IUCN.UK.2011-2.RLTS.T201627A9154955.en
2
use it as breeding habitat. Other native fish eat the young leaves of Water Onion.
Systems: Freshwater
Use and Trade (see Appendix for additional information)
The species is popular with aquarists because it is easy to maintain, highly tolerant of temperature and
light variations. The bulb is also used to produce a cream for softening the skin.
Investigations carried out by IUCN revealed that a buyer in Kuraburi used to purchase about 10,000
bulbs/day from local communities about 10 years ago. However, this amount has declined sharply over
the past four years. At present (2008), he purchases at the rate of 1 Baht per bulb, and sells it to an
exporting company in Bangkok at 5 Baht/bulb. The export company sells each bulb for 2-5 US$, in
foreign destinations.
Threats (see Appendix for additional information)
A major threat to the habitat of this species is the dredging of rivers and streams for removal of
sediment and rock for construction and land reclamation purposes (this has also increased the speed of
water flow in habitats of the Water Onion, where entire subpopulations have been dislodged). Also
threatened by diversion of the rivers and streams for agricultural purposes. There is also extensive
changes in the ecology of the streams and rivers due to land use changes in the adjoining areas (e.g.,
clearing of forest for agriculture) and resultant land-based erosion and river bank erosion (the substrate
of the Nakha and Kuraburi rivers has changed drastically over the past 10 years, due to erosion. The
muddy substrate that facilitates the growth of Water Onion has been replaced by pebbles, rock and
gravel, in large areas of these rivers. Collection of bulbs from the wild for sale to the international trade
for home fish ponds and aquaria is also a threat which needs closer monitoring.
Conservation Actions (see Appendix for additional information)
The Office of National Environmental Policy and Planning in Thailand (ONEPP) has declared this species
as nationally endangered (http://www.onep.go.th/). Local conservation groups in the Ranong province
have also initiated the conservation of this species in its wild habitats (Youth group and Plern Prai Sri Na
Ca Conservation Group established by Klong Na Ca Wildlife Sanctuary). The youth group is involved in
awareness campaigns, ex situ propagation of Water Onion in nurseries, rescue of dislodged Water Onion
deposited on river banks and subsequent re-planting in the wild. The Pleun Prai Sri Na Kha Conservation
Group, together with the local authority organizes tourist visits (in dinghy paddle boats) along Na Kha
river to observe Crinum thaianum during its flowering period (October-December) every year. About
600 Thai tourists visited the area in 2007. A fee of 450 Thai Baht (ca. 15 US$) is charged to each visitor.
Credits
Assessor(s):
Soonthornnawaphat, S., Bambaradeniya, C. & Sukpong, P.
Reviewer(s):
Hilton-Taylor, C. & Lutz, M.L.
© The IUCN Red List of Threatened Species: Crinum thaianum – published in 2011.
http://dx.doi.org/10.2305/IUCN.UK.2011-2.RLTS.T201627A9154955.en
3
Bibliography
IUCN. 2011. IUCN Red List of Threatened Species (ver. 2011.2). Available at: http://www.iucnredlist.org.
(Accessed: 10 November 2011).
Leeratiwong, C. and Jornead, S. 2005. Species diversity of vascular plants in Si Phang-nga National Park,
Phangnga Province. J.Songklanakarin Journal of Science and Technology 27(4): 769-787.
Citation
Soonthornnawaphat, S., Bambaradeniya, C. & Sukpong, P. 2011. Crinum thaianum. The IUCN Red List of
Threatened Species 2011: e.T201627A9154955. http://dx.doi.org/10.2305/IUCN.UK.20112.RLTS.T201627A9154955.en
Disclaimer
To make use of this information, please check the Terms of Use.
External Resources
For Images and External Links to Additional Information, please see the Red List website.
© The IUCN Red List of Threatened Species: Crinum thaianum – published in 2011.
http://dx.doi.org/10.2305/IUCN.UK.2011-2.RLTS.T201627A9154955.en
4
Appendix
Habitats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Habitat
Season
Suitability
Major
Importance?
5. Wetlands (inland) -> 5.1. Wetlands (inland) - Permanent
Rivers/Streams/Creeks (includes waterfalls)
-
Suitable
Yes
5. Wetlands (inland) -> 5.2. Wetlands (inland) Seasonal/Intermittent/Irregular Rivers/Streams/Creeks
-
Marginal
-
Use and Trade
(http://www.iucnredlist.org/technical-documents/classification-schemes)
End Use
Local
National
International
Medicine - human & veterinary
Yes
Yes
No
Pets/display animals, horticulture
No
No
Yes
Establishing ex-situ production *
No
No
No
Threats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Threat
Timing
Scope
Severity
Impact Score
2. Agriculture & aquaculture -> 2.1. Annual &
perennial non-timber crops -> 2.1.3. Agro-industry
farming
Ongoing
-
-
-
Stresses:
1. Ecosystem stresses -> 1.1. Ecosystem conversion
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
-
Stresses:
1. Ecosystem stresses -> 1.1. Ecosystem conversion
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
-
Stresses:
1. Ecosystem stresses -> 1.1. Ecosystem conversion
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
-
Stresses:
1. Ecosystem stresses -> 1.1. Ecosystem conversion
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
-
Stresses:
2. Species Stresses -> 2.1. Species mortality
2. Agriculture & aquaculture -> 2.2. Wood & pulp
plantations -> 2.2.1. Small-holder plantations
2. Agriculture & aquaculture -> 2.2. Wood & pulp
plantations -> 2.2.2. Agro-industry plantations
3. Energy production & mining -> 3.2. Mining &
quarrying
5. Biological resource use -> 5.2. Gathering terrestrial
plants -> 5.2.1. Intentional use (species is the target)
© The IUCN Red List of Threatened Species: Crinum thaianum – published in 2011.
http://dx.doi.org/10.2305/IUCN.UK.2011-2.RLTS.T201627A9154955.en
-
-
-
-
-
-
-
-
5
7. Natural system modifications -> 7.2. Dams & water
management/use -> 7.2.3. Abstraction of surface
water (agricultural use)
7. Natural system modifications -> 7.2. Dams & water
management/use -> 7.2.9. Small dams
9. Pollution -> 9.3. Agricultural & forestry effluents ->
9.3.2. Soil erosion, sedimentation
11. Climate change & severe weather -> 11.4. Storms
& flooding
Ongoing
-
-
Stresses:
1. Ecosystem stresses -> 1.1. Ecosystem conversion
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
-
Stresses:
1. Ecosystem stresses -> 1.1. Ecosystem conversion
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
-
Stresses:
1. Ecosystem stresses -> 1.1. Ecosystem conversion
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
-
Stresses:
1. Ecosystem stresses -> 1.2. Ecosystem degradation
2. Species Stresses -> 2.1. Species mortality
2. Species Stresses -> 2.2. Species disturbance
-
-
-
-
-
-
-
Conservation Actions in Place
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Conservation Actions in Place
In-Place Land/Water Protection and Management
Occur in at least one PA: Yes
Conservation Actions Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Conservation Actions Needed
2. Land/water management -> 2.1. Site/area management
2. Land/water management -> 2.3. Habitat & natural process restoration
3. Species management -> 3.1. Species management -> 3.1.1. Harvest management
3. Species management -> 3.1. Species management -> 3.1.2. Trade management
3. Species management -> 3.3. Species re-introduction -> 3.3.1. Reintroduction
3. Species management -> 3.4. Ex-situ conservation -> 3.4.1. Captive breeding/artificial propagation
4. Education & awareness -> 4.2. Training
4. Education & awareness -> 4.3. Awareness & communications
Research Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
© The IUCN Red List of Threatened Species: Crinum thaianum – published in 2011.
http://dx.doi.org/10.2305/IUCN.UK.2011-2.RLTS.T201627A9154955.en
6
Research Needed
1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.5. Threats
3. Monitoring -> 3.1. Population trends
3. Monitoring -> 3.2. Harvest level trends
3. Monitoring -> 3.3. Trade trends
3. Monitoring -> 3.4. Habitat trends
Additional Data Fields
Distribution
Estimated area of occupancy (AOO) (km²): 48
Continuing decline in area of occupancy (AOO): Yes
Estimated extent of occurrence (EOO) (km²): 641
Continuing decline in number of locations: Yes
Lower elevation limit (m): 50
Upper elevation limit (m): 150
Population
Continuing decline of mature individuals: Yes
Population severely fragmented: Yes
Continuing decline in subpopulations: Yes
Habitats and Ecology
Continuing decline in area, extent and/or quality of habitat: Yes
© The IUCN Red List of Threatened Species: Crinum thaianum – published in 2011.
http://dx.doi.org/10.2305/IUCN.UK.2011-2.RLTS.T201627A9154955.en
7
The IUCN Red List Partnership
The IUCN Red List of Threatened Species™ is produced and managed by the IUCN Global Species
Programme, the IUCN Species Survival Commission (SSC) and The IUCN Red List Partnership. The IUCN
Red List Partners are: BirdLife International; Botanic Gardens Conservation International; Conservation
International; Microsoft; NatureServe; Royal Botanic Gardens, Kew; Sapienza University of Rome; Texas
A&M University; Wildscreen; and Zoological Society of London.
THE IUCN RED LIST OF THREATENED SPECIES™