The objective of the present study was to examine the ecological indices and mapping the mangrove ecosystem in the coastal region of Maitara Island, North Moluccas Province. The study was conducted during 2015 at three stations. The results showed that 4 species of mangrove belong to 3 families were recorded during the study. The total density of stations was 215.78 tree/hectare, the frequency was 722.22 tree/hectare, the percent cover was 189.29% and the significant value was 300 in every station. Rhizopora apicullata, Avicennia alba, Sonneratia alba have the highest density and frequency, while the lowest density and frequency were Sonneratia caseolaris. Sonneratia alba, S. caseolaris, Avicennia alba have the highest percent cover. Overall, the diversity of mangroves is minor. The characterization of zonation showed that Rhizhopora sp. is a leading constituent of mangrove ecosystem from coast line to the hinterland of Maitara Island.

The existence of seagrass ecosystems in the coastal region of small islands has been playing an essential role as a habitat and the supplier of fish resources, as well as a shore and coastline protector of small islands. This study aimed to determine the distribution, composition, density, coverage, and associations of seagrass plant in the islands of Hiri, Ternate, Maitara, and Tidore. Data were collected by using line transect method and quadrate transect. Furthermore, data were analyzed by using MS Excel and XLstat software. The results showed that Tidore Island has the highest number of seagrass species namely eight from nine species of seagrasses found in all research sites. Three species of seagrasses, Enhalus acoroides, Thalassia hemprichii, and Cymodocea rotundata, were widespread in all four islands. The composition, density and coverage of seagrass species varied among research stations. Vegetation of seagrasses found in the study site in the form of mixed vegetation consisting of three to eight species. Enhalus acoroides found mostly in Mtr1 and Tte2 stations were not associated with other seagrass species, nor Cymodocea serrulata that found in Mtr2 Station and T. hemprichii at Tdr2 and Tdr3 stations. The associations of C. rotundata and Syringodium isoetifolium were observed at Tdr1 and Hr1 Stations. While Halophila ovalis and Halophila spinulosa showed no association with other seagrass species at the study area. Overall the condition of the marine environment on the four islands is still relatively good and able to support the life of the seagrass ecosystem. ABSTRAKKeberadaan ekosistem lamun di perairan pesisir pulau-pulau kecil berperan penting sebagai habitat dan penyedia sumber daya ikan, serta pelindung garis pantai dan daratan pulau-pulau kecil tersebut. Penelitian ini bertujuan untuk menganalisis sebaran, komposisi, kerapatan, penutupan dan asosiasi jenis lamun di perairan pulau-pulau kecil Hiri, Ternate, Maitara dan Tidore, Maluku Utara. Pengambilan data dengan menggunakan metode transek garis dan transek kuadrat. Selanjutnya data dianalisis dengan menggunakan bantuan perangkat lunak MS Excel dan XLstat. Hasil penelitian menunjukkan bahwa Pulau Tidore memiliki jumlah jenis lamun terbanyak yakni delapan jenis lamun dari sembilan jenis lamun yang ditemukan di seluruh lokasi penelitian. Tiga jenis lamun yaitu, Enhalus acoroides, Thalassia hemprichii dan Cymodocea rotundata, menyebar luas dan terdapat di keempat pulau tersebut. Komposisi, kerapatan dan penutupan jenis lamun bervariasi antar stasiun penelitian. Vegetasi lamun yang ditemukan di lokasi penelitian berupa vegetasi campuran yang terdiri dari tiga sampai delapan jenis lamun. E. acoroides banyak ditemukan di Stasiun Mtr1 dan Tte2 tidak berasosiasi dengan spesies lainnya, demikian juga dengan C. serrulata yang ditemukan di Stasiun Mtr2 dan T. hemprichii di Stasiun Tdr2 dan Tdr3. Asosiasi C. rotundata dan Syiringodium isoetifolium terlihat di stasiun Tdr1 dan Hr1, sementara Halophila ovalis dan H. spinulosa tidak menunjukkan asosiasi denga...

Authors. 2018. Morphometric characteristics of two seagrass species (Enhalus acoroides and Cymodocea rotundata) in four small islands in North Maluku, Indonesia. Biodiversitas 19: 2035-2043. Seagrass has an important ecological role as a protector of coastlines and small islands. It is known to be capable of forming phenotypic plasticity through morphometric variation as a response to its environmental conditions. This study aimed to determine the distribution and morphological differences between populations of two important seagrass species (Enhalus acoroides and Cymodocea rotundata) in the waters around four small islands in North Maluku. The study was conducted at two stations in each of Ternate Island and Maitara Islands, three stations at Tidore Island and one station at Hiri Island. A line transect method was used to collect seagrass samples. Morphometric characteristics included leaf sheath length, leaf length, leaf width, rhizome diameter, root length, root diameter, and internode length were measured. Discriminant analysis was performed to describe morphometric characteristics distinctive of the four islands. Leaf sheath length, leaf length, rhizome diameter, and root length of E. Acoroides differed significantly among the populations from the various islands except for leaf width. Meanwhile, leaf sheath length, leaf width, rhizome diameter, root length, and internode length differed significantly in C. rotundata among the populations from different islands except for leaf length.

This study is aimed at analyzing the molecular identification and the level of the genetic diversity of seagrass species as a basis information for the local genetic conservation. Sampling of both species, Enhalus acoroides and Cymodocea rotundata, was carried out at four small islands at North Maluku, namely Hiri, Ternate, Maitara, and Tidore Island. Locus used in genetic analysis is the chloroplast genome (rbcL and matK). The results of this work indicated that the rbcL genetic marker were able to identify species well but were low in discrimination and divergence of species, thus is not give the good results for genetic diversity level. Conversely, matK genetic marker, although a little weak in identifying species, have good results in the discrimination and divergence of species. matK genetic marker were able to provide a description of genetic diversity level. The results of this study found that the level of genetic diversity of E. acoroides (Hn: 13; Hd: 0.862; π: 0.273) and C. rotundata (Hn: 19; Hd: 0.975; π 0.119) were higher at Tidore Island compared to the three others. This indicated that the high genetic diversity at Tidore Island can be used as a basis for local genetic conservation and maintenance of biodiversity.

Seagrass ecosystems are located between mangrove ecosystems and coral reefs. Seagrass ecosystems are habitats and foraging area for many marine organisms. Eco-biological cycles in seagrass ecosystems are important for maintaining populations of many organisms. Seagrass at Hiri Island is distributed horizontally along the coast. This island is also a location where Dugong dugon is found North Maluku. Dugong dugon is a vurneable species that has been included in the IUCN and Appendix I Cites. This study aimed to identify species, density of seagrass and existence of Dugong dugong. The survey method used quadratic transect method to collect seagrass data. The Results found 6 species of seagrass at Hiri Island. Five species of those seagrass (Cymodocea serrulata, Cymodecea rotundata, Halodule uninervis, Halodule pinifolia, Halophila spinulosa) are known as food of Dugong dugon. The highest species density was shown by Halodule uninervis. The presence of Dugong dugon and its feeding trail was found during field survey. Information on seagrass species and Dugong dugon sightings location can be used for endangered species conservation policies. Management and conservation efforts need to be done to maintain seagrass ecosystem and Dugong dugon potential habitat at Hiri Island.