Community structure of echinoderms in seagrass ecosystem of Pandaratan Beach, Tapanuli Tengah Regency, North Sumatera

Abstract

This study aimed to determine the community structure of echinoderms and how it related to seagrass cover and water chemical and physical parameters in Pandaratan Beach, Tapanuli Tengah Regency. The research was conducted from Maret to April 2018. Data analysis included community structure analysis and Principal Component Analysis (PCA). The result showed that there were seven species of echinoderms from four classes in Pandaratan Beach. The station I had the highest composition of echinoderms, while the lowest noted at station II. The highest abundance of 77 ind/m2 was found at the station I and the lowest of 44 ind/m2 was at station III. The highest diversity index was recorded at the station I, while the highest evenness and dominance index was at station II. Water quality of the waters was still in capacity to support the life of echinoderms. Based on PCA analysis, it was obtained that the abundance of echinoderms was positively correlated with seagrass cover, DO, depth, and phosphate.

Holothurian assemblages before the harvest-boom era in inner reefs of Ishigaki Island, focusing on population dynamics of lollyfish <i>Holothuria atra</i> Jäger, 1833

“…We found that H. leucospilota preferred BR, often inserting their posterior end in the stable rocks as anchors, as reported by Bonham & Held (1963). This defensive behavior from predators seems to be the primary factor for the habitat selection of this species, although that they are also known to utilize SG habitats (Setyastuti et al 2018, Komala et al 2019, Susetya et al 2019.…”

Spatial models of suitable sandy substrates for brittle star community conservation in Sancang Coast, West Java, Indonesia

“…The selected sandy substrates in this study indicate that brittle stars prefer lower temperatures and avoid substrates with warm water. According to Angreni et al (2017) and Susetya (2019), Brittle star abundance was negatively correlated with temperature because high temperatures would cause high evaporation, increasing salinity. An increase of 3 in salinity would lead to flaking skin or even death in extreme conditions (Fang et al 2014).…”

“…Indonesian waters were also reported to have significant brittle star biodiversity within the Indo-Pacific region. In Pandaratan Beach of Sumatra Island, brittle stars accounted for 9.15%-14.71% of the echinodermata community registered for Ophiocoma erinaceus (Müller & Troschel, 1842) species (Susetya 2019). Even on Java Island (Pakpahan et al 2020), brittle stars are known to dominate the intertidal zones.…”

Species Composition, Relative Abundance and Distribution of Sea Cucumber in the Intertidal Zone of Cab-ilan Island, Dinagat, Dinagat Islands, Philippines

“…The low diversity observed at the station may be attributed to high pH levels. Arthaz et al (2015) and Susetya et al (2019) have highlighted the dangers associated with high pH levels, as they can disrupt the metabolic activities and respiration of echinoderms, including sea cucumbers, ultimately leading to death of the biota.…”