MEPS 174:247-256 (1998)  -  doi:10.3354/meps174247

Species composition and plant performance of mixed seagrass beds along a siltation gradient at Cape Bolinao, The Philippines

Steffen S. Bach1, Jens Borum1,*, Miquel D. Fortes2, Carlos M. Duarte3

1Freshwater Biological Laboratory, University of Copenhagen, Helsingørsgade 51, DK-3400 Hillerød, Denmark
2Marine Science Institute, College of Science, University of The Philippines, Diliman, 1101 Quezon City, The Philippines
3Centro de Estudios Avanzados de Blanes, CSIC, Camino de Santa Barbara, E-17300 Blanes, Girona, Spain
*Addressee for correspondence. E-mail:

ABSTRACT: The response of mixed Southeast Asian seagrass beds to siltation was analyzed based on field data, a transplantation experiment and experimental manipulation of light availability in seagrass populations along a silt gradient at Cape Bolinao, The Philippines. Seagrass species diversity, shoot density and depth penetration declined with increasing amounts of suspended material and increasing water column light attenuation along the silt gradient. The seagrass species could be ranked according to decreasing tolerance to siltation as: Enhalus acoroides > Cymodocea serrulata > Halodule uninervis > Thalassia hemprichii > Halophila ovalis > Cymodocea rotundata > Syringodium isoetifolium. A gradual decline in shoot density and depth penetration of the different species along the silt gradient suggested that changes in the vertical light attenuation coefficient in the water column, primarily caused by differences in suspended inorganic solids, was the most important factor affecting seagrass performance. However, inconsistency among the species in response to increasing water depth, artificial shading and transplantation indicated that other factors, such as siltation-derived changes in sediment conditions, contribute to the sequential loss of seagrass species along the silt gradient.


KEY WORDS: Seagrasses · Siltation · Eutrophication · Transplantation · Artificial shading


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