ABUNDANCE ANALYSIS OF Sesarma spp. AND THE ENVIRONMENTAL FACTORS IN TAMAN WISATA ALAM ANGKE KAPUK JAKARTA

• Main Author: Ayuningtyas Sahadatina, Saskia
• Format: Final Project
• Language: Indonesia
• Subjects: Ilmu hayati ; Biologi
• Online Access: https://digilib.itb.ac.id/gdl/view/39857
• Institution: Institut Teknologi Bandung

Crabs are macrofauna found in many mangrove ecosystems and plays an important role in the cycle of nutrients in it. One genus of mangrove crabs, Sesarma, was found to dominate Taman Wisata Alam Angke Kapuk (TWA), DKI Jakarta. Environmental factors greatly influence the survival of Sesarma spp. because Sesarma spp. is very sensitive to changes and disturbances that occur in their habitat. This study aims to determine the abundance of Sesarma spp., measure environmental factors in the habitat of Sesarma spp., and determine the relationship (correlation) of environmental factors with the abundance of Sesarma spp. in three stations in TWA Angke Kapuk that differ in terms of the environmental view and the crowds of visitors. Data collection was done on 8-11 March 2019. Station 1 is located near the lodging facilities (Villa Pondok Alam) with an open environmental view and bridges built for visitors. Station 2 is located near the water tourism area and birds observation area with environmental view tends to be open and crowded with visitors because it’s a place for planting mangroves. Station 3 is located close to the reclamation area with an environmental view that tends to be closed and visitors pass quite a lot. Data collection of crab abundance was done on two plots of 2×2m for each station by counting the crabs in the plot at 11.00-18.00 WIB, for four days. The crabs observed are marked with white paint on the carapace to avoid double counting. The crab that hides in the hole is dug directly or awaited until it comes out then captured by hand. Environmental factors data such as pH, temperature, substrate moisture, and organic matter content were taken in 2×2m plots, while water salinity data was taken in 10×10m plots. The correlation of environmental factors with the abundance of crabs was analyzed by Pearson correlation analysis. From the results of the study concluded, estimation of the highest abundance of Sesarma spp. is at Station 1 which is 77.500 ind/ha, probably because crab habitat is not directly disturbed by visitors because there are bridges over it. Abundance at Station 2 is 35.000 ind/ha may be related to the discovery of Javan pond heron (Blekok) known as the predator of Sesarma spp. Abundance at Station 3 is 31.250 ind/ha allegedly related to the amount of waste carried from the sea and the reclamation area. The results of the measurement of environmental factors for Station 1, 2, and 3 are as follows: the average temperature of the substrates are 27.4±0.5oC; 27.9±0.5oC; and 28.2±1.1oC; the average pH of the substrates are 6.65±0.30; 6.30±0.39; and 5.68±1.13; the average of substrate moistures are 82.5±8.4%; 96.3±4.4%, and 100.0±0.0%; salinities measurements are 4.14 ppt; 10.61 ppt; and 10.05 ppt; and organic matter content of substrates are 44.39%; 41.93%; and 43.93%. The abundance of Sesarma spp. has strong negative correlation with salinity (r = -0.991) and substrate moisture (r = -0.998), positively correlated with pH (r = 0.988) and organic matter content (r = 0.601), and moderate negative correlation with temperature (r = - 0.451).