The Effect of Shore Height on the Distribution of Upper Intertidal Seagrass in the Andaman Sea, Thailand.

Autor: Yaowaluk Monthum, Attawut Khantavong, Nuttiga Hempattarasuwan, Chainarong Roengthong, Pattama Tongkok, Jittraporn Chusrisom, Chatcharee Kaewsuralikhit
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Zdroj: Journal of Fisheries & Environment; May-Aug2023, Vol. 47 Issue 2, p73-84, 12p
Abstrakt: Shore height is one of the physical factors in marine ecology affecting marine organisms in the upper intertidal area. This study aimed to investigate the effect of shore height on the distribution of three dominant seagrass species in the upper intertidal area of the Andaman Sea in the provinces of Krabi and Trang, southern Thailand. Shore height data were collected from 155 stations in 2021 and 273 stations in 2022, using a theodolite (AP-8 Nikon) and a surveyors' rod. The measured height from the field was calculated relative to the height of water predicted above the lowest low water on a specific date and time, thus shore height is presented as the height above lowest low water (cm H_LLW). The total aboveground biomass of the three dominant seagrass species, namely, Enhalus acoroides, Thalassia hemprichii and Halophila ovalis, was observed through a modified Rapid Visual Estimation Technique. At different shore heights (0-100, 100-180, and above 180 cm H_LLW), the coverage of total seagrasses was highly significant (F = 9.08, p = 0.002); the biomass was also highly significant (F = 18.72, p<0.001). The highest total biomass (10.56±6.66 g dw·m-2 with 55.00±24.05% coverage) was found at 100-120 cm H_LLW. The shore height affected the presence of seagrass, with distinct shallow thresholds observed for E. acoroides, T. hemprichii and H. ovalis of 200, 200 and 220 cm H_LLW, respectively. The findings from this study hold significant implications for guiding decisionmaking processes related to seagrass restoration and transplantation efforts. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index