Recovery of Natural Zostera Bed after Typhoon Attacks and Autonomous Restoration of Zostera Bed by Backfilling Old Navigation Channel at the Mouth of Imazu River in Hiroshima Bay

The objective of this study is to clarify the characteristics of natural Zostera bed recovery and verify autonomous Zostera restoration by backfilling depression (old navigation channel) after the disappearance of beds caused by typhoon attacks, on the coast of Iwakuni. After the disappearance, firs...

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Bibliographic Details
Published inJournal of Japan Society on Water Environment Vol. 39; no. 4; pp. 97 - 102
Main Authors HIRAOKA, Kiyonori, OMICHI, Yuhei, NAKAHARA, Shinya, KAWAMOTO, Yasunori, TERAWAKI, Toshinobu, OKADA, Mitsumasa
Format Journal Article
LanguageJapanese
Published Tokyo Japan Society on Water Environment 2016
Japan Science and Technology Agency
Subjects
Backfill
Flowering
Hurricanes
Light intensity
Luminous intensity
Navigation
Recolonization
Recovery
Restoration
Rivers
Seeding
Shoots
Tidal flats
Transplantation
Typhoon
Typhoons
Zostera bed
Zostera japonica
Zostera marina
Zostera restoration
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Summary:The objective of this study is to clarify the characteristics of natural Zostera bed recovery and verify autonomous Zostera restoration by backfilling depression (old navigation channel) after the disappearance of beds caused by typhoon attacks, on the coast of Iwakuni. After the disappearance, first, Zostera beds, which consisted of Zostera japonica Aschers. et Graebn., appeared in tidal flats at the mouth of Imazu River, and then Zostera beds recovered rapidly, with Zostera marina L. recolonization. The backfilled area had optimum light intensity, sand movement and sediment for Z. marina in three or four years. Not only vegetative shoots of Z. marina and Z. japonica, but also flowering shoots of Z. marina appeared at the backfilled area without transplanting or seeding. Z. marina and Z. japonica tend to increase in density and coverage, respectively, and Zostera distribution patterns of the backfilled area were almost the same as those of a natural habitat. These results suggested that the recovery of Zostera beds on the coast of Iwakuni began with the recolonization of Z. japonica in tidal flats at the mouth of Imazu River, followed by the rapid recovery of Zostera beds by Z. marina recolonization. In addition, it was considered possible to restore self-sustaining Zostera beds by backfilling depression.
ISSN:0916-8958
1881-3690
DOI:10.2965/jswe.39.97