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Phyllospadix iwatensis

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Taxonomy [top]

Kingdom Phylum Class Order Family
PLANTAE TRACHEOPHYTA LILIOPSIDA NAJADALES ZOSTERACEAE

Scientific Name: Phyllospadix iwatensis
Species Authority: Makino
Common Name(s):
English Surfgrass, Species code: Pi

Assessment Information [top]

Red List Category & Criteria: Vulnerable B1ab(ii,iii) ver 3.1
Year Published: 2010
Date Assessed: 2008-08-11
Assessor(s): Short, F.T. & Waycott, M.
Reviewer(s): Livingstone, S., Harwell, H. & Carpenter, K.E.
Justification:
Phyllospadix iwatensis has a limited distribution in Korea, China and Japan. This species is naturally fragmented due to a lack of suitable substrate. There have been declines recorded in Korea and Japan. Losses of unknown magnitude have occurred since the start of extensive kelp aquaculture in Northern China. Major threats to this species are coastal development and shoreline hardening, pollution, eutrophication and aquaculture. The recruitment rate of this species is low as it inhabits a high energy environment, where conditions need to be right for seeds to be successful. The extent of occurrence of P. iwatensis is less than 20,000 km². This species meets the threshold for criterion B1, with a continuing decline in area and quality of habitat, and with less than 10 known locations and a fragmented population. This species is listed as Vulnerable.

Geographic Range [top]

Range Description: Phyllospadix iwatensis is found in the northwestern Pacific in China, Korea, Japan and the Russian Federation. However, its distribution is not well known and is believed to be limited. The extent of occurrence of P. iwatensis is less than 20,000 km² and it is known form less than 10 known locations.
Countries:
Native:
China; Japan; Korea, Democratic People's Republic of; Korea, Republic of; Russian Federation
FAO Marine Fishing Areas:
Native:
Pacific – northwest
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Phyllospandix iwatensis is limited throughout most of its range, except in China where only remnant populations remain since the start of extensive kelp aquaculture. There is evidence that there have been declines in Korea (K-S. Lee pers. comm. 2008). This species is naturally fragmented due to a lack of suitable substrate.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: Phyllospadix iwatensis inhabits the intertidal and subtidal rocky bottoms of temperate regions of Japan. In South Korea it occurs mainly on rocky substrata along the east coast. Although observed in both sheltered and open shores, this species usually grows in high-energy environments. The optimum period for growth of P. iwatensis is in March (Yabe et al. 1996).

This species can grow in dense foliage with high shoot density of both intertidal and subtidal plants, which is likely to be an adaptation to heavy water movement. In choppy and swell sea, P. iwatensis did not seem to be adapted to growing in the subtidal zone, where there can be a shortage of light (Yabe et al. 1996).

Surfgrass recruitment has an obligate requirement for anchoring by turfy seaweeds in the surf zone. If the seaweed community changes to micro-algae, recruitment will most likely fail.

This species is found to depths of 4.5 m.
Systems: Marine

Threats [top]

Major Threat(s): This species is threatened by industrial developments in coastal regions, land reclamation (shoreline hardening). Loss of vegetation also results from water pollution, coastal eutrophication, disturbance of habitats by fish trawling, clamming and aquaculture.

The recruitment rate of this species is low as it inhabits a high energy environment, where conditions need to be right for seeds to be successful.

Conservation Actions [top]

Conservation Actions: The distribution of Phyllopadix iwatensis falls into protected areas in South Korea (Environmental Conservation Areas or Special Coastal Management Areas), and it is protected by 'The Marine Ecosystem Conservation and Management Act' in Korea.

Bibliography [top]

Green, E.P. and Short, F.T. 2003. World Atlas of Seagrasses. University of California Press, Berkeley.

IUCN. 2010. IUCN Red List of Threatened Species (ver. 2010.3). Available at: http://www.iucnredlist.org. (Accessed: 2 September 2010).

Kuo, J., Aioi, K. and IilzumiI, H. 1988. Comparative leaf structure and its functional significance in Phyllospadix iwatensis Makino and Phyllospadix japonicus Makino (Zosteraceae). Aquatic Botany 30(3): 169-187.

Yabe, T., Ikusima, I. and Tsuchiya, T. 1996. Production and population ecology of Phyllospadix iwatensis Makino. 2. Comparative studies on leaf characteristics, foliage structure and biomass change in an intertidal and subtidal zone. Ecological Research 11(3): 291-297.

Yabe, T., Ikusima, I. and Tsuchiya, T. 1996. Production and population ecology of Phyllospadix iwatensis Makino. I. Leaf growth and biomass in an intertidal zone. Ecological Research 10(3): 291-299.


Citation: Short, F.T. & Waycott, M. 2010. Phyllospadix iwatensis. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 27 December 2014.
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