No abstract

Abstract. Setyadi G, Pribadi R, Wijayanti DP, Sugianto DN. 2021. Mangrove diversity and community structure of Mimika District, Papua, Indonesia. Biodiversitas 22: 3562-3571. Despite being one the largest mangrove forest in the world, there are few studies on mangrove diversity and community structure in Mimika, Papua Province. The study collected data from 4 estuaries of Mimika Region, i.e. Kamora, Tipuka, Ajkwa and Minajerwi. Mangrove species, tree diameter at breast height and canopy height data were collected in 10 m x 10 m plot with three replicates for distance, specifically 0, 250, and 500m perpendicular to the riverbank. This study found 66 mangroves species consisting of 20 major, 10 minor, and 36 associate mangrove species. Their density ranged from 577-1,345 trees ha-1 with diversity Shannon-Weiner diversity indices (H’) ranging from 0.62-1.19 and Evenness Index (J’) ranging from 0.09-0.18. The canopy height of the mangrove trees was ranged from 9-42.5 m. The highest density species was Rhizophora apiculata (333 ha-1) followed by Avicennia marina, Bruguiera gymnorrhiza, and Camptostemon schultzii, while B. parviflora, S. alba, and X. granatum were the least dominant. Regarding basal area, R. apiculata and B. gymnorrhiza were the highest with medians of 7,853 cm2 ha-1 and 5,201 cm2 ha-1 respectively. In the low tidal zone area, mangrove was dominated by A. marina, Sonneratia alba and R. mucronata. Medium low to medium high tidal zones were dominated by B. gymnorrhiza, R. apiculata, and B. parviflora. The high tidal zone was more dominated by Nypa fruticans.

Abstract. Munasik, Sabdono A, Assyfa AN, Wijayanti DP, Sugiyanto, Irwani, Pribadi R. 2020. Coral transplantation on a multilevel substrate of Artificial Patch Reefs: effect of fixing methods on the growth rate of two Acropora species. Biodiversitas 21: 1816-1822. Branching Acropora is generally used in coral transplantation to rehabilitate coral reefs. However, these corals are sensitive to environmental changes. Artificial Patch Reef  (APR) is an artificial structure that provides a multilevel hard substrate. The purpose of the study was to investigate the effectiveness of the APR structure to facilitate the growth and survival of Acropora branching. Two species Acropora aspera and Acropora copiosa were transplanted vertically and horizontally on a modular concrete block in different levels of APR situated in the shallow reef of Panjang Island, Central Java. The results showed that the coral growth rate varied from 96.7 to 346.9 cm3/month, while survival ranged from 30 to 100% after 8 months. Lower survival rate mostly was found in the upper level of APR. The statistical analyses showed that the growth rate of A. copiosa fragment was significantly higher than that of A. aspera  (p<0.05). Moreover, there were also significant differences in the treatments of transplantation method  (p<0.05) to enhance coral growth. However, multilevel substrates were not significantly influenced by coral growth. This study suggested that A. copiosa which has high-level complexity in branching pattern will be selected to apply in shallow reef rehabilitation with transplanted vertically.

Genetic diversity and population structure in the fiddler crab Austruca perplexa were investigated to acquire a better understanding of the evolutionary history of the species. Nucleotide sequence analysis was performed from a polymerase chain reaction-amplified fragment of the mitochondrial DNA control region. A 691 bp nucleotide sequence was obtained from 618 specimens collected from 13 sites across Japan, Taiwan, the Philippines, Indonesia and Australia. Haplotype diversity ranged from 0.8 to 0.99, and nucleotide diversity values were lower (range, 0.30–1.9%) than those reported previously for other crustacean taxa. Gene flow was evident within populations in Japan and western Indonesia, but absent among all other populations, including eastern Indonesia. This pattern conforms to the one observed in many other marine taxa across the major biogeographical region referred to as Wallacea. The population pairwise fixation index (FST) and FST  P-values were high and significant among many sites, implying that gene flow is restricted among most of the geographical regions sampled here. We hypothesize that physical oceanic barriers coupled with a short pelagic larval duration are responsible for creating the patterns we found. Strong evidence for population structure in a species that has relatively high dispersal potential, resulting in among-population differentiation, is a potential driver of evolutionary novelty. Our results provide a foundation for developing better conservation strategies for this widespread intertidal species.

No abstract

No abstract

Abstract. Indrayanti E, Zainuri M, Sabdono A, Wijayanti DP, Pranowo WS, Siagian HSR. 2019. Larval dispersal model of coral Acropora in the Karimunjawa Waters, Indonesia. Biodiversitas 20: 2068-2075. Identification of connectivity patterns through the larval dispersal dynamics is urgently needed to support the sustainable larval supply. Many studies on the larval coral distribution have been reported. However, no study of coral larval dispersal has been conducted in Karimunjawa. The purpose of this research was to build a model of coral larval dispersal in Karimunjawa waters. Modeling was carried out by using a 2-dimensional hydrodynamic current approach with a particle tracking module. The larval release was conducted during the full moon in the first transition period (April) and the second transition period (October). The larval source was assumed from around Sambangan waters. Modeling validation was done by comparing the model results to the direct of current measurements with Acoustic Doppler Current Profiler (ADCP). The results of larval dispersal model showed that both the transition seasons I and II were similar in the direction of movement towards the west. This result indicated that currents, tides, and winds influenced the larval dispersal process. Also, the model results showed that Sambangan, Tengah, Cilik, Sintok, the west site of Karimun, Menjangan Kecil, and Menjangan Besar Islands were identified as the location of the larval settlement.

Equatorial corals were previously thought not to spawn synchronously at the assemblage level. However, recent studies have reported multi-specific coral spawning events in equatorial regions. Here, we report the reproductive activity of 21 Acropora species in the Karimunjawa Archipelago over five consecutive years (2008-2012). We also infer the month of spawning for Acropora humilis, Acropora gomezi, and Acropora muricata from the presence of mature oocytes. We found that Acropora assemblages exhibit a high degree of inter-specific reproductive seasonality. The highest proportion of colonies with mature oocytes was observed in March 2011 (65%, n = 80). Oocytes likely developed during June-March, 6 to 10 months before spermatogenesis. Spermatocytes were observed in samples collected during March; however, the onset of spermatogenesis could not be precisely determined as samples were not collected in January and February. This was because of weather constraints and difficulty in detecting the early stages of spermatogenesis. Multi-specific spawning events were observed during the first transition period (March-April) and the second transition period (September-October) between monsoons. The number of species containing mature oocytes was higher during March-April (12 species) and September-October (8 species). Spawning patterns likely follow the lunar cycle. However, two distinct spawning events coincided with two periods of higher temperature (March-April and September-October). Daily temperature records indicate that spawning occurred on days where temperature dropped before the expected spawning time during the warming period. During the period of rising temperature, wind speeds were lower, which might serve as a signal leading to the multi-specific spawning of corals in the tropics, at least in the Karimunjawa Archipelago of Indonesia.