Structure and relationship of crabs (Brachyura) with the environment at mangrove ecosystem Canal Areas, Karimunjawa National Park, Central Java

Abstract

Putriningtias A, Bengen DG, Moosa MK. 2014. Structure and relationship of crabs (Brachyura) with the environment at mangrove ecosystem Canal Areas, Karimunjawa National Park, Central Java. Bonorowo Wetlands 4: 82-93. The mangrove ecosystem of Karimunjawa National Park was relatively good and natural, used as ecotourism area. Karimunjawa National Park Authority provides some facilities such as mangrove tracking. The existence of mangrove tracking was predicted would give some influence to the ecological condition of crabs, so it is necessary to study on crabs and its baseline data for monitoring environmental condition purposes due to the ecotourism area establishment. Sampling was done during September-Oktober 2013 at mangrove ecosystem, Karimunjawa National Park. Sampling sites were determined by purposive sampling method. The sample was taken using qualitative method in 1m x 1m transect. Result of this study shows that there are four species from four families: Metopograpsus thukuhar (Grapsidae), Thalamita crenata (Portunidae), Macrophthalmus (Macrophthalmus) parvimanus (Macrophthalmidae), dan Uca vocans vocans (Ocypodidae). In the study, Uca vocans vocans was the species that have been found in the large number. The highest total crab abundance was found at station I (92 ind./100m2), and the lowest was at station III (32 ind./100m2). The Value of Diversity Index (H’) was in low-mid category and Uniformity Index was in mid-high category. There is no domination at station I, while at station II and III shows there's a domination pattern. Generally, the crabs were in an unstable condition because The Diversity Index showed low category. The abundance distribution pattern of species showed that crabs tended to follow the conditions of their environment and it was within their tolerable limits for life.