Seagrass Community Structure of Kumbang Waters-Karimunjawa Islands

Seagrass is found in shallow waters that have an important role in marine life and is one of the most productive marine ecosystems. This study aims to determine the structure of seagrass communities in Kumbang Island, Karimunjawa. Data collected during observations in the field include species identification, number of individual/stand, percent cover of each species. Percent cover of seagrass was observed by using square transect with size of 1x1 m. Transect was divided into 25 pieces of smaller size i.e. 20 cm2. The stands of seagrass is a collection of several fused leaf base. The number of stands were directly counted. Sampling were done twice i.e. June and September 2012. The results showed that the seagrass community in the waters of Kumbang island, Karimunjawa, can be classified as mixed community consisting of 1-5 types of seagrass. In total, six species of seagrass were found in the area i.e. Thalassia hemprichii, Cymodocea rotundata, C. serrulata, Halodule pinifolia, Halodule ovali and Halophila uninervis. C. serrulata was only discovered during second sampling in September 2012. In the first sampling (June 2012), the density of seagrass (stand/m²) T. hemprichii was the highest (77.11), while the lowest was H. pinifolia (0.56). The results of second sampling showed that H. uninervis was found to be higher than T. hemprichii. Frequency of seagrass types in June and September 2012 showed the value from 0 to 15.67 and 0-16 with T. hemprichii was found more frequently than other types of seagrass during both sampling time. Percent coverage of seagrass species (%/m2) during June and September 2012 showed the value of 0,11-15.67 and 0-29.29, respectively. T. hemprichii and H. uninervis have the highest average percent cover in September and June 2012 sampling.