Investigation of the community structure of seagrasses in the coastal areas of Iligan City, Mindanao, Philippines

Investigation of the seagrass community structure was done in twelve coastal Barangays of Iligan City, Lanao del Norte namely: Barangay Buru-un, Maria Cristina, Tominobo, Tambacan, Saray, Canaway, Santiago, Hinaplanon, Sta. Filomena, Acmac, Kiwalan and Dalipuga. The seagrass community structure was assessed using the transect-quadrat method and several parameters were determined namely: species composition, number of species, abundance, occurrence and dominance of species. The distribution pattern of seagrasses in each sampling areas were also determined. Some environmental parameters were obtained such as water temperature, salinity, pH, Total Suspended Solids (TSS) and type of substratum. Among the twelve coastal barangays studied, eight were found to have seagrasses and three were devoid of seagrass growth. Barangay Dalipuga had the highest abundance of seagrasses followed by Samburon with fair seagrass habitat condition. There were five species of seagrass identified namely: Thalassia hemprichii, Halodule uninervis, Syringodium isoetifolium, Cymodocea serrulata and Halophila ovalis. T. hemprichii had the highest percent cover hence, the most abundant and dominant species followed by S. isoetifolium. Majority of the seagrass species showed an aggregated or clumped type of distribution. C. serrulata showed a close association with Total Suspended Solids (TSS) while T. hemprichii and H. uninervis showed a close association with temperature, salinity and pH. Moreover, H. ovalis and S. isoetifolium shows no association to any of the environmental parameters indicating that these species could tolerate to any changes in the environmental parameters measured.