마이크로네시아 축에 형성된 해초지대의 구성과 형상

Abstract

Three seagrass species were record from this study. The seagrass bed is dense and mostly sandy on the area close to coastline from middle sites. Average seagrass cover at S1 is more than 70% and dominated by Cymodocea rotundata. Other species at this site include Enhalus acoroides. S2 and S3 are fishing ground and commonly collect sea cucumber and sea urchins for both subsistence and commercial purpose. The sites had an average seagrass cover comprising 95% of area and dominated by Cymodocea rotundata, Enhalus acoroides and Syringodium isoetifolium. At S4, the seagrass bed was sparse and the average seagrass cover sharply decreased. On the contrary the diverse and area cover of algal species were markedly increased. Halimeda spp. was most commonly encountered macro-algae and chlorophyta. A total of 14 species of macro-invertebrate were associated with all seagrass beds around study area. Holothuroideans such as Synaptula sp 1., Bohadschia mamorata, and Holothuria hilla were commonly occurred on S1 to S4. The species belong to echinoideans Echinothrix sp., Mespilia globules and Tripneustes gratilla that observed within meadows and after middle part of the study area. From the seagrass, algae and macro-invertebrate species composition and abundance at each sampling site, 4 type of habitats were recognized; dense seagrass type a (Cymondocea rotundata dominant) at S1 (Figure 3), dense seagrass type b (Cymondocea rotundata>Syringodium isoetifolium >Euhalus acoroides) at S2 and S3, mixed seagrass/algae/coral type (Halimeda spp. dominant) at S4.